U5 O1 - Neurological and Ophthalmic Emergencies

Question 1

What is ataxia?

Answer 1

Incoordination of the limbs that can cause swaying,

abnormal carriage of limb(s) etc

Question 2

What is blepharospasm?

Answer 2

Rapid blinking of the eyelids often in response to ocular pain or irritation.

Question 3

What is clonus?

Answer 3

Involuntary, regular rhythmic contractions and relaxation of muscles

Question 4

What is hemiparesis?

Answer 4

Weakness of 2 limbs on the same side.

Question 5

What is horners syndrome?

Answer 5

Drooping of the eyelid (ptosis), constriction of the pupil

myosis/miosis) and retraction of the eyeball into the socket (enophthalmos

Question 6

What is Hyphaemia?

Answer 6

Blood in the anterior chamber of the eye

Question 7

What is Hypopyon?

Answer 7

Pus in the anterior chamber of the eye

Question 8

What is nystagmus?

Answer 8

Abnormal movement of the eyes in synchrony. There is
usually a slow phase in one direction; and then a fast phase as the eyes flick back to their origin. It may be horizontal, vertical or rotational and it may only occur when the head position is altered (positional nystagmus).

Question 9

What is Opisthotonus?

Answer 9

Strong contraction of the extensor muscles of the neck and back. This results in arching of the back; and
hyperextension (backward arching) of the head and neck - often with extension of the fore limbs.

Question 10

What is paralysis?

Answer 10

Loss of motor (muscle) function. Generally used in

reference to a limb but could also be e.g. facial paralysis

Question 11

What is paresis?

Answer 11

Partial loss of motor (muscle) function. Usually used in

reference to a limb but can also be used in relation to other parts of the body such as the eye

Question 12

What is proprioception?

Answer 12

The sensory function which allows the animal to be aware of and adopt the normal limb positioning

Question 13

What is Schiff-Sherrington posture ?

Answer 13

Increased forelimb extensor tone secondary to a serious injury from T3-L3

Question 14

What is Spasticity?

Answer 14

An increase in the tone/activity of the extensor muscles of limb(s) leading to rigid paralysis: hypertonia

Question 15

What is a spinal reflex?

Answer 15

Automatic response to a particular stimulus which involves spinal cord nerve pathways. Examples include the patellar reflex, cutaneous trunci reflex and perineal reflex.

Question 16

What is strabismus?

Answer 16

A squint where both or one eye deviates from the normal position: usually ventrally and medially.

Question 17

What is syncope?

Answer 17

A collapse/faint

Question 18

What is tetraparesis?

Answer 18

Partial loss of motor (muscle) function in all 4 limbs.

Question 19

What is tonus?

Answer 19

Increased extensor tone of muscles

Question 20

The initial emergency neurological assessment involves assessing what three basic features?

Answer 20

The initial emergency neurological assessment involves assessing three basic features to try and quickly identify the severity and location of the neurological problem. It does not replace a full neurological assessment but can provide valuable
early information to allow emergency treatment to be provided without wasting valuable time. The three features to assess are:
1) Mental status
2) Ambulation
3) Cranial and spinal nerve function

An initial hands- off assessment is important. Visual assessment of level of consciousness and abnormalities is important e.g. nystagmus, miosis, balance issues etc. It is Important to remember that mental status is also affected by cerebral
perfusion so anything that interferes with this could affect the patient’s mental status.

Question 21

How do you assess the mental status in an initial neurological assessment?

Answer 21

Mental status
This is an assessment of the patient’s level of alertness and can be tested in a number of ways. Hands off observation of the patient is very important - initially a
clinical assessment of the degree of consciousness of the patient should be made i.e. is it alert/awake. This can progress on to an assessment of the response to
external stimuli: such as a loud noise; or light; or the response to touch/noxious stimuli. Response to touch around the head, especially around the nose, medial
canthus of the eye and the ears, is particularly important to assess mental status,

Question 22

How do you assess the ambulation in an initial neurological assessment?

Answer 22

Ambulation
This is the assessment of the animal’s ability to walk and move normally. If affected, an assessment of the degree of ataxia should be made. If limb function is reduced or impaired, is this localised to one limb, one side, or does it involve all four limbs?

In addition, some postural reactions, including basic proprioception tests, can be performed by knuckling over the paws in turn to see if the patient immediately
replaces the foot to its normal position. Any delay or failure to reposition the foot indicates a loss of sensory and / or motor nerve function to that limb.

Noxious stimuli are useful to test pain pathways and deep nerve function. These are classically performed by applying haemostats across the nail bed of the patient. The response should be vocalisation and / or movement of the head around to the side affected. Lack of response or reduced response suggests reduced function or lack of deep pain sensation which has a poor prognosis. This assessment should not be
performed if a patient has normal limb motor function. Due to the potential to cause pain, deep pain assessment should only be performed on veterinary direction.

Question 23

How do you assess the mental status in an initial neurological assessment?

Answer 23

Cranial nerves
A full cranial nerve assessment is unlikely to be performed as part of the initial assessment – however an initial brief assessment of cranial nerve abnormalities can be helpful e.g. balance issues might indicate an issue with CN VIII, the vestibulocochlear nerve, or the cerebellum.

The following cranial nerves can be tested to help locate the source of a neurological
problem involving the head and neck:
 Cranial nerve II optic nerve
 Cranial nerve III oculomotor nerve
 Cranial nerve IV trochlear nerve
 Cranial nerve VI abducens nerve
 Cranial nerve VII facial nerve
 Cranial nerve VIII vestibulocochlear nerve
 Cranial nerve IX glossopharyngeal nerve
 Cranial nerve X vagus nerve
 Cranial nerve XII hypoglossal nerve
Cranial nerve II and cranial nerve VII can be tested by assessing the menace response reflex i.e. does the patient blink when an object is moved rapidly towards them? Cranial nerve II travels directly from the back of the globe, through the calvarium and to the vision centre in the forebrain, close to the midbrain. On the
ventral brain there is some crossing over of the left and right optic nerves at the optic chiasma: so part of the left optic nerve crosses over to the right side of the brain and vice versa. The sensory nervous impulses are analysed in the vision centre: resulting in motor nerve impulses being transmitted in cranial nerve VII to the eyelids to cause blinking. An abnormal response can indicate damage or disease of the retina, cranial
nerve II, the vision centre of the forebrain or cranial nerve VII.

Question 24

What following cranial nerves can be tested to help locate the source of a neurological problem involving the head and neck?

Answer 24

The following cranial nerves can be tested to help locate the source of a neurological problem involving the head and neck:
 Cranial nerve II optic nerve
 Cranial nerve III oculomotor nerve
 Cranial nerve IV trochlear nerve
 Cranial nerve VI abducens nerve
 Cranial nerve VII facial nerve
 Cranial nerve VIII vestibulocochlear nerve
 Cranial nerve IX glossopharyngeal nerve
 Cranial nerve X vagus nerve
 Cranial nerve XII hypoglossal nerve

Question 25

What is the Cranial nerve II?

Answer 25

Cranial nerve II optic nerve

Question 26

What is the Cranial nerve III?

Answer 26

Cranial nerve III oculomotor nerve

Question 27

What is the Cranial nerve IV?

Answer 27

Cranial nerve IV trochlear nerve

Question 28

What is the Cranial nerve VI?

Answer 28

Cranial nerve VI abducens nerve

Question 29

What is the Cranial nerve VII?

Answer 29

Cranial nerve VII facial nerve

Question 30

What is the Cranial nerve VIII?

Answer 30

Cranial nerve VIII vestibulocochlear nerve

Question 31

What is the Cranial nerve IX?

Answer 31

Cranial nerve IX glossopharyngeal nerve

Question 32

What is the Cranial nerve X?

Answer 32

Cranial nerve X vagus nerve

Question 33

What is the Cranial nerve XII?

Answer 33

Cranial nerve XII hypoglossal nerve

Question 34

How do you test Cranial nerve II and cranial nerve VII?

Answer 34

Cranial nerve II and cranial nerve VII can be tested by assessing the menace response reflex i.e. does the patient blink when an object is moved rapidly towards them? Cranial nerve II travels directly from the back of the globe, through the calvarium and to the vision centre in the forebrain, close to the midbrain. On the
ventral brain there is some crossing over of the left and right optic nerves at the optic chiasma: so part of the left optic nerve crosses over to the right side of the brain and vice versa. The sensory nervous impulses are analysed in the vision centre: resulting in motor nerve impulses being transmitted in cranial nerve VII to the eyelids to cause blinking. An abnormal response can indicate damage or disease of the retina, cranial
nerve II, the vision centre of the forebrain or cranial nerve VII.

Question 35

How do you test Cranial nerve III?

Answer 35

Cranial nerve III can be assessed by observing the pupil and noting its response to light stimuli: as this nerve is involved in controlling the iris. An initial assessment
should be made of:
 Pupil size: normal, abnormally constricted (miosis) or dilated (mydriasis)
 Pupils symmetry: asymmetry may suggest a unilateral problem (anisocoria)
 Pupil response to light
The pupillary light/motor reflex (PLR/PMR) assesses the function of cranial nerve II, the vison centre and cranial nerve III. If there is damage to this pathway, reduced or
absent pupillary light reflex responses will be evident: i.e. when a bright light is shone into the eye the pupil does not constrict or shows a reduced/sluggish response. Due to the crossing over of fibres of cranial nerves II and III (decussation),there should be a consensual light reflex as well as a direct response: i.e. when light is shone into one eye, the opposite pupil should constrict (consensual response) as well as the
pupil into which the light is shone (direct response). In addition, cranial nerve III (along with cranial nerves IV and VI innervates) innervates the extraocular muscles:
these cause movement of the eyeball/globe in the orbit. Damage to these nerves can interfere with movement or cause a squint: strabismus. As cranial nerve III arises
from the rostral midbrain, damage to this area could affect its function.

Question 36

What disease simultaneously affects Cranial nerves IV, VI and VIII?

Answer 36

Cranial nerves IV, VI and VIII are often simultaneously affected if a patient has vestibular disease. Loss of function of the trochlear nerve (IV) results in a dorsolateral strabismus; loss of function of the abducens nerve (VI) results in medial strabismus; and loss of the vestibulocochlear nerve (VIII) function results a head tilt, circling, abnormal posture and balance. Vomiting may occur and there may be unilateral loss of hearing: although this is hard to assess. Nystagmus (abnormal horizontal or vertical eye movements) may also be present if cranial VIII is not functioning:

Question 37

What can damage to cranial nerves IX, X and XII result in?

Answer 37

Damage to cranial nerves IX, X and XII may all result in dysphagia and altered/absent gag reflex (i.e. when something is placed into the back of the patient’s
throat, a gag or swallow reflex should result).
As cranial nerve X (the vagus) has so many functions, damage to it could be associated with various clinical signs e.g. altered heart rate, blood pressure or
phonation.

Question 38

What are the different spinal reflexes that may be assessed?

Answer 38

Assessment of other nerves
Assessment of spinal reflexes may provide information about the spinal cord function and help to localise lesions. There are a large number of spinal reflexes which may be assessed including:
 Patella reflex
 Cranial tibial reflex
 Gastrocnemius reflex
 Triceps reflex
 Perineal reflex
 Withdrawal reflex

Question 39

What are the many causes of seizures?

Answer 39

There are many causes of seizures: both intra-cranial and extra-cranial e.g. trauma, metabolic disease, toxicity, neoplasia, porto-systemic shunt. The commonest cause of seizures is idiopathic epilepsy

Question 40

What is a seizure?

Answer 40

Seizures (Fitting)
A seizure is an abnormal event which arises from excessive neuronal activity in the cerebral cortex. It is not a disease process but a sign of an underlying condition.

The pathophysiology of seizures is complex. The condition occurs as a consequence of rapid, uncontrolled firing of nerve cells (neurons) within parts of the brain.

Question 41

What two types of seizures may an animal present with?

Answer 41

The clinical presentation of an animal having a seizure depends on whether the seizure activity is generalised or partial/localised.

Question 42

What type of seizures are dogs most likely to demonstrate?

Answer 42

Depending on the underlying cause, dogs are more likely to demonstrate generalised seizure activity:

Question 43

What type of seizures are cats most likely to demonstrate?

Answer 43

cats more likely to exhibit partial seizure activity

Question 44

What parts of the brain are involved in generalised seizures and how do generalised seizures affect the patient?

Answer 44

Generalised seizures involve both cerebral hemispheres: the animal is likely to be unconscious with seizure activity affecting both sides of the body. Abnormal neuronal activity on both sides of the brain usually presents as bilaterally symmetrical trunk and limb movements.
Generalised seizures are often associated with tonic/clonic activity

Question 45

What are partial seizures caused by?

Answer 45

Partial seizures are caused by abnormal neuronal activity that is localised to an area of the forebrain/cerebrum.

Question 46

What are the two types of partial seizures?

Answer 46

Partial motor:

Psychomotor

Question 47

What is a partial motor seizure?

Answer 47

Partial seizures are caused by abnormal neuronal activity that is localised to an area
of the forebrain/cerebrum.
These may be:
 Partial motor: a partial seizure with signs such as tonus or clonus of one or more limbs or twitching of the face.

Question 48

What is a partial psychomotor seizure?

Answer 48

Partial seizures are caused by abnormal neuronal activity that is localised to an area
of the forebrain/cerebrum. These may be:

 Psychomotor: partial seizures which lead to various behavioural changes such as vocalisation, tail-chasing, aggression etc.

Question 49

What is status epilepticus?

Answer 49

Status epilepticus is an emergency which requires prompt veterinary attention.
Status epilepticus (S.E.) is usually considered to be continuous seizure activity lasting five minutes or longer; or cluster seizures where the patient does not regain consciousness between seizures.

Question 50

What two categories can the causes of seizures be divided in to ?

Answer 50

Seizures are caused by extra-cranial or intra-cranial causes

Question 51

What are the possible causes of extracranial seizures?

Answer 51

Extra-cranial causes:
There are many possible causes:
 metabolic disorders such as hypoglycaemia or hypocalcaemia
 organ disease e.g. cirrhosis of the liver; porto-systemic shunt or kidney failure
 toxicity e.g. ethylene glycol
Neurons are very sensitive to toxins (neuro-toxins) and this can cause seizure activity

Question 52

What are the possible causes of intracranial seizures?

Answer 52

Intracranial causes:
There are also many possible causes:
 trauma
 infection
 congenital defects
 acquired conditions e.g. hydrocephalus
 neoplasia
 inflammatory conditions e.g. granulomatous meningo-encephalitis (GME)
 idiopathic epilepsy which is often inherited

Question 53

If the seizures are caused by uraemia what other clinical signs may have been seen?

Answer 53

if the seizures are caused by uraemia, secondary to chronic renal failure, the patient may have a history of polyuria and polydipsia, weight loss and vomiting. Clinical findings may include uraemic halitosis
and oral ulceration; dehydration and emaciation

Question 54

How can idiopathic epilepsy be confirmed?

Answer 54

If the animal has idiopathic epilepsy (this can only be confirmed by ruling out all other potential causes), it is usually young, of a certain breed and was normal prior to the seizure.

Question 55

What is important at identifying the potential cause of a seizure when carrying out a consultation?

Answer 55

Clinical presentation
As mentioned above, the patient presentation varies depending on the cause of the seizure. The history is very important in attempting to identify an underlying cause: potential access to toxins; recent trauma; previous seizure activity; normal or abnormal before seizures started.

Question 56

What are the 4 basic stages of a seizure?

Answer 56

There are 4 basic stages to a seizure: 1) the prodromal stage, 2) the aura or pre-ictal stage, 3) the ictal or seizure stage, and 4) the post-ictal stage

Question 57

Describe the prodromal stage of a seizure?

Answer 57

Depending on the cause, the prodromal stage may precede the actual seizure by hours or days. It may be characterised by a change in mood or behaviour. Humans with epilepsy can experience mood changes, headaches, insomnia or feelings about the impending seizure: ‘seizure alert’ dogs can be trained to recognise impending seizure activity in their owners. Some owners can recognise when their pet is going to have a seizure due to behaviour changes.

Question 58

Describe the aura stage of a seizure?

Answer 58

The aura stage signals the start of the seizure. Signs are usually localised and can include restlessness, nervousness, whining, trembling, salivation, affection,
wandering, hiding, hysterical running, and apprehension.

Question 59

Describe the ictal stage of a seizure?

Answer 59

The ictal stage is the actual seizure- if generalised, there is likely to be a sudden increase in muscle tone; loss of consciousness; and stimulation of the autonomic
nervous system, often with hypersalivation, defaecation and urination. The ictus (seizure or fit) is either tonic (rigid) or tonic-clonic (rigidity interspersed with jerking
muscle activity): generally lasting up to 1-3 minutes.

Question 60

Describe the post-ictal stage of a seizure?

Answer 60

The post-ictal stage may be the only sign of a seizure that the owner sees particularly since many seizures occur at night or early in the morning. For minutes
to days after the seizure, the dog may be confused, disoriented, restless, or unresponsive, or may wander or suffer from transient blindness. At this stage the
animal is conscious but does not behave in their usual manner. They may display signs of exhaustion, altered temperament, polyphagia and/or polydipsia

Question 61

What telephone advice should be given to an owner who’s pet has been seizuring?

Answer 61

Telephone guidance is often required for these cases. Most animals with idiopathic epilepsy will have seizures which start when resting and stop spontaneously,
especially if external stimuli are controlled e.g. noise, light etc. Telephone advice should be aimed at limiting patient and owner injury- the animal should not be
handled unless its position means it is in danger; if possible, any furniture that may pose a threat should be moved; lights should be dimmed and the time should be noted. It can be helpful to suggest filming their animal’s behaviour.
It is, however, crucial to identify those cases where immediate veterinary attention is
required e.g.
 possible status epilepticus
 hypoglycaemia
 hypocalcaemia
 intra or extra-cranial trauma

Question 62

When is immediate veterinary attention required in a patient that is seizuring?

Answer 62

It is, however, crucial to identify those cases where immediate veterinary attention is required e.g.
 possible status epilepticus
 hypoglycaemia
 hypocalcaemia
 intra or extra-cranial trauma.

The history is very important e.g. the patient with diabetes mellitus who has had a recent increase in insulin dose requires an emergency source of glucose prior to veterinary attention; the Yorkshire terrier which has recently had puppies need immediate veterinary attention for treatment of hypocalcaemia. If in doubt veterinary guidance should be sought. Appropriate guidance on the safe transport of patients will be required. Secondary complications such as hyperthermia have to be considered.

Question 63

How do you carry out an initial quick neurological assessment?

Answer 63

Patient Assessment
The patient will need to be assessed on presentation. An initial quick neurological assessment can be made by hands-off observation e.g. conscious, ambulatory,
ataxic, and alert; stuporous; obtunded; unconscious; seizuring etc.
An assessment of respiration and perfusion parameters e.g. pulse rate and quality; mucous membrane colour and CRT should be made. Emergency oxygen should be available.

Question 64

What sample collection and testing is usually carried out on a patient with seizures and when should sample collection be carried out?

Answer 64

Sample collection and testing
In general, and where possible, blood samples should be obtained prior to treatment.
Any seizuring or unconscious patient should have blood glucose levels assessed immediately to rule out hypoglycaemia or hyperglycaemia. A full haematological and biochemical profile can be helpful in identifying the underlying cause and appropriate
emergency treatment. Ideally this should include blood gas analysis, PCV, blood smear examination and ionised calcium assessment. N.B. cerebral hypoxia can
cause seizures
Samples may additionally be required for toxicology or assessment of serum insulin, thyroid hormones or anticonvulsant levels. Further dynamic testing of liver function e.g. bile acid stimulation test may be required.
It is useful to store and freeze spun down and separated serum, for analysis of anticonvulsant drug levels, should the patient already be on medication for epilepsy.
In addition serum can be used to test for antibodies to viruses such as distemper.

Question 65

When is medication required in a patient that’s seizuring?

Answer 65

Initial medication
If the seizure is mild and lasts less than a couple of minutes, there may be no need to medicate the animal.
Emergency treatment is required for status epilepticus. There are various definitions of status epilepticus- it is either prolonged seizure activity or two or more seizures without full recovery of consciousness during the inter-ictal period. Any patient that has been seizuring continually, for five minutes or more, needs to be seen as an emergency.

Treatment (although not usually emergency treatment) may also be required for patients that have had two or more seizures within a 24 hour period (known as
cluster seizures). It is important to ascertain whether the patient is currently receiving any medication, including anticonvulsant therapy. Advising owners to bring anticonvulsant medication that has been prescribed to an emergency appointment can be helpful.

Question 66

What treatment is required for a patient seizuring due to a hypoglycaemic episode?

Answer 66

If the patient is hypoglycaemic on presentation this should be addressed by IV administration of 0.5–1.0 mL/kg of 50% dextrose. As this hyperosmolar solution can cause phlebitis, dextrose can be added to intravenous fluids to make a 2.5% or 5% solution

Question 67

What are the important considerations when placing an intravenous catheter in a patient that has presented with seizures?

Answer 67

Where possible, intravenous (IV) access, should be obtained initially. For speed of action and to allow titration to effect, most emergency anticonvulsant therapy is administered by the intravenous route- some medications are irritant if injected perivascularly (e.g. diazepam and phenobarbital).

Place a long line that has been flushed.

Question 68

What emergency drugs are usually administered as an emergency treatment for an animal that is seizuring?

Answer 68

Emergency treatment should be selected by the veterinary surgeon but could include the following options:
 Benzodiazepines (diazepam, midazolam)
 Phenobarbital, alone or following diazepam/midazolam
Levetiracetam

Question 69

What are the important considerations when administering benzodiazepines in a seizuring patient?

Answer 69

Benzodiazepines (diazepam, midazolam) are often the first line of treatment in the emergency patient- they can be effective in many patients at a low dose
(Charalambous, 2018). If IV access is not possible, they can be administered by rectal, intramuscular (IM), buccal or sublingual routes – N.B. diazepam should not be injected by the IM route due to the potential for tissue damage.
In addition to IV bolus therapy, diazepam MAY be administered as a CRI (but with extreme caution in cats).

Question 70

What are the important considerations when administering phenobarbital in a seizuring patient?

Answer 70

Phenobarbital, alone or following diazepam/midazolam, can be administered as a slow IV bolus. This may be repeated as required BUT care should be
taken to leave at least 30 minutes between doses as this drug takes 20-30 minutes to reach full effect. It is also important to ascertain whether the patient is already receiving oral phenobarbitone medication. If so blood should be obtained to assess serum phenobarbitone level and the amount of intravenous phenobarbitone should be calculated with this in mind

Question 71

What nerve is recognised as having anti-convulsive effects?

Answer 71

Vagal nerve stimulation is also recognised as having anti-convulsive effects

Question 72

What drugs can be administered if IV access is not possible in a seizuring patient?

Answer 72

If IV access is not possible, diazepam may be administered per rectum at 0.5- 1mg/kg- this can be repeated every ten minutes up to a maximum of three times in a 24-hour period (BSAVA, 2014). The response to this can be quite variable with the response being quite poor in some patients. Recent work has
demonstrated the effectiveness of intranasal administration of midazolam in the emergency management of the seizuring patient. It is also reported to cause less CNS and respiratory depression than diazepam

Question 73

If seizuring continues despite the administration of initial medication, what is it necessary to do?

Answer 73

If seizuring continues despite the above initial medication it will be necessary to move on to another course of therapy.
1) Propofol may be administered as a series of IV boluses to effect (up to a maximum of 6mg/kg); it is then continued as a lower dose constant rate infusion.
2) Ketamine can be administered as a bolus and continued as a CRI
3) Fosphenytoin can also be used as an IV bolus.
If this is not successful, inhalant anaesthesia with isoflurane can be performed.

Question 74

What monitoring and post seizure care is required for a patient that has presented with seizures?

Answer 74

Careful patient monitoring is required- this includes ensuring the patient has a patent airway; is breathing adequately; is cardiovascularly stable and is normothermic (the patient may initially be hyperthermic but may then develop hypothermia). The mean arterial blood pressure should be maintained at 80-100 mmHg to ensure adequate cerebral perfusion. It is essential to avoid hypotension - cerebral perfusion (CPP) depends on mean systemic arterial pressure (MAP) and intracranial pressure (ICP) – (CPP = MAP – ICP). Either increased ICP or decreased MAP can decrease cerebral perfusion. If the patient is hypoventilating or has lost its swallow/gag reflex, an endotracheal tube should be placed and ventilation provided. If the patient is breathing well, additional oxygen could be provided via a facemask ( or the means most tolerated). As with traumatic brain injury, the patient should be placed on a board that is raised 15-30 degrees and be turned every 2-4 hours. Appropriate ocular and oral care should be provided e.g. sterile ocular lubricant. Ideally an indwelling urinary catheter should be placed to ensure adequate urine output of 1-2 ml/kg/hr, assess specific gravity and to note urine colour: Myoglobinuria may occur secondary to the muscle damage caused by seizure activity.
Ongoing aseptic management of the intravenous catheter is essential to ensure patency for maintenance of drug and IV fluid administration. Warmed IV fluids should be delivered at the rate indicated by the patient’s hydration and circulation status: both over-infusion and under-infusion must be avoided. 0.9% sodium chloride infusion would not be appropriate for a dog already being medicated with potassium
bromide.
A neurological assessment should be regularly performed and recorded within the medical record: the patient should be monitored carefully for signs of increased intracranial pressure.
Mentation and cranial nerve reflexes should be assessed:
1) PLRs
2) Pupil asymmetry (anisocoria)
3) Pupil size
4) Gag reflex
5) Facial sensation
6) Strabismus
7) Nystagmus
Blood samples should be regularly assessed for glucose, electrolytes, PCV, TP, urea and creatinine levels. Arterial blood gases, SpO2 and blood pressure should be monitored too.

Question 75

What type of fluids would not be appropriate for a dog already being medicated with potassium bromide?

Answer 75

0.9% sodium chloride infusion would not be appropriate for a dog already being medicated with potassium bromide

Question 76

What cranial nerve reflexes should be assessed and monitored in a patient post seizure?

Answer 76

Mentation and cranial nerve reflexes should be assessed:

1) PLRs
2) Pupil asymmetry (anisocoria)
3) Pupil size
4) Gag reflex
5) Facial sensation
6) Strabismus
7) Nystagmus

Question 77

What further investigation (after initial emergency treatment) is required for the diagnosis and treatment of a brain tumour or idiopathic epilepsy?

Answer 77

Further investigation, including MRI/CT, will often be required to reach a diagnosis.
If the patient is diagnosed with a brain tumour or idiopathic epilepsy (IE), ongoing anticonvulsant therapy is likely to be required. For dogs not having cluster seizures, either imepitoin or phenobarbitone is the initial medication of choice for IE.
Depending on response to treatment other medications such as potassium bromide may be added in. Phenobarbitone is used for cats with IE. Serum levels of any anticonvulsant should be regularly checked. A full discussion of IE is beyond the
scope of these course notes.

Question 78

What might traumatic spinal cord injuries arise due to?

Answer 78

Traumatic spinal cord injuries may arise due to:

1) vertebral trauma
2) intervertebral disc(s) protrusion or prolapse
3) ischaemic myelopathy due to fibro-cartilaginous embolism

Question 79

What vertebral injuries can occur as a result of trauma?

Answer 79

Vertebral injuries (e.g. fall, RTA) can result in complicated (spinal cord injury) fractures or luxations/subluxations (displacement) of vertebrae.

Question 80

What breeds do Hansen type I disc extrusions occur relatively frequently in and what is this secondary to?

Answer 80

Hansen type I disc extrusions occur relatively frequently in chondrodystrophic breeds (e.g. Bassett Hound, Dachshund) secondary to chondroid degeneration of the nucleus pulposus in the intervertebral disc

Question 81

What happens with Hansen type I disc extrusions and how dog usually acquire it?

Answer 81

This, usually inherited tendency, leads to mineralisation and calcification of the affected discs with loss of shock-absorbing ability. The degenerating disc(s) may put gradual pressure on the spinal cord, causing clinical signs but often the extrusion occurs suddenly leading to spinal cord compression. More significantly, dorsal rupture of the annulus fibrosis may occur suddenly resulting the nucleus pulposus and other disc material moving into the spinal canal, causing spinal cord compression and affecting function.

Question 82

What is Hansen type !! disc protrusion and what is it secondary to?

Answer 82

Hansen type II disc protrusion is secondary to fibroid disc degeneration- a bulging, intact annulus fibrosis or a partially ruptured annulus fibrosis causes spinal cord
compression. In this case, however, the nucleus pulposus remains within the disc. Fibroid disc degeneration can occur in any breed of dog, but is more common in older, large breed dogs. Calcification of the disc is rare and the clinical signs are often more insidious and chronic.

Question 83

What areas do disc extrusion and protrusion most commonly affect?

Answer 83

Disc extrusion or protrusion is most likely to arise in the cervical, caudal thoracic or
lumbar areas. It is less common between T1 and T11 due to the presence of strong
intercapital ligaments between T2 and T10.

Question 84

What does the severity of disc extrusion/protrusion depend on?

Answer 84

The severity of the clinical signs depend on:
 The force with which the disc extrudes
 The degree of damage to the spinal cord caused by the extruded disc material
 The extent of the local haemorrhage, inflammatory response and cord
swelling
 The degree of spinal cord compression and the progression.

Question 85

What are Fibrocartilaginous emboli? What clinical signs does it cause? What breeds does it affect most commonly and where does it arise?

Answer 85

Fibrocartilaginous emboli (FCE) are damaged disc fragments (usually from the nucleus pulposus) which can block the local arteries supplying the spinal cord,
cutting off the blood supply. The infarction causes a generally painless, nonprogressive ischaemic myelopathy in affected animals. FCE usually occur in
younger, medium to large breed dogs ( although all dogs and cats may be affected) with no prior warning They most commonly arise in the lumbar region, interrupting transmission of ascending and descending nerve impulses, thus causing hind limb paresis or paralysis which may be uni or bilateral.

Question 86

What may be the cause of chronic, non-traumatic spinal cord disease?

Answer 86

Additional, usually more chronic, non-traumatic causes of spinal cord disease
include:
1) Neoplasia
2) Spinal cord or canal haemorrhage (producing a compressive lesion of the spinal cord)
3) Discospondylitis (infection of the vertebrae and disc)
Neoplasms can arise from any structure within the spinal column (or vertebral column) and so can occur at any point.

Question 87

What is discospondylitis, where does it usually occur and what are the clinical signs?

Answer 87

Discospondylitis (infection of the vertebrae and disc)

Discospondylitis typically occurs around the L7/S1 area and is often associated with haematogenous spread of bacteria, often from urinary tract infections, to the
vertebrae. Affected animals are often systemically unwell with localised pain e.g. pyrexia and anorexia in addition to having neurological clinical signs

Question 88

How should a patient with a possible or actual spinal injury be moved?

Answer 88

It is very important that any animal with possible or actual spinal cord injury is moved carefully so that no further damage is done. The use of a spinal board and /or stretchers - with rolled towels placed along the animal’s flanks, to prevent rolling and excessive movement, is advised. Lifting of the patient should be performed by two or more people with the aim of minimising movement of the spinal column.

Question 89

How should you initially manage and assess a patient with a possible or actual spinal cord injury?

Answer 89

It is very important that any animal with possible or actual spinal cord injury is moved carefully so that no further damage is done. The use of a spinal board and /or stretchers - with rolled towels placed along the animal’s flanks, to prevent rolling and excessive movement, is advised. Lifting of the patient should be performed by two or more people with the aim of minimising movement of the spinal column.
The patient should be triaged with airway, breathing and circulation assessed; hypotension, hypovolaemia and hypoxaemia should be managed if necessary. Pain
levels should also be assessed.
Following, initial triage, a detailed history and examination is required which will assist in both localising and gauging the severity of the problem. The assessment of cranial nerve and spinal cord reflex actions can assist in localisation of the lesion;
monitor patient progress.
Clinical signs will depend on the cause and severity of the injury. There may be contusion, laceration, compression, decreased blood supply and vertebral instability.
Vertebral instability can lead to repeated spinal cord trauma. Animals with spinal cord injuries are likely to have normal mentation: although they may be subdued.
Their cranial nerve reflex actions will be unaffected.

Question 90

How do you localise spinal cord injuries of C1-C5, what signs may be seen?

Answer 90

Spinal segment lesion C1-C5
Depending on the severity of the injury, these cases will have tetraparesis or tetraplegia. Spinal reflexes are likely to be present in all four limbs- they may be
normal or exaggerated
Severe injury could cause paresis or paralysis of the muscles of respiration which could lead to a rapid deterioration in the patient’s condition or sudden death.

Question 91

How do you localise spinal cord injuries of C6-T2, what signs may be seen?

Answer 91

Spinal segment lesion C6-T2
Depending on the severity of the injury, these cases will have tetraparesis or tetraplegia. Spinal reflexes are likely to be present in the hind limbs where they may
be normal or exaggerated; spinal reflexes will be reduced or absent in the forelimbs.
Breathing may also be affected as the intercostal muscles may be paretic or paralysed: leaving only the diaphragm as the muscle of respiration. Unilateral lesions in the area of T1-T3 often produce an ipsilateral Horner’s syndrome.

Question 92

How do you localise spinal cord injuries of T3-L3, what signs may be seen?

Answer 92

Spinal segment lesion T3-L3
This is a common site for spinal cord lesions especially from T10-L3. The forelimbs are normal. Depending on the severity of the injury, these cases will have paraparesis or paraplegia. Spinal reflexes are likely to be present in all four limbs they may be normal or exaggerated in the hind limbs.

Schiff-Sherrington posture may be seen in cases of serious of spinal cord injury of this region- there is markedly increased forelimb muscle tone with extensor rigidity: the hind limb reflexes may be normal to decreased.
Whilst this occurs with serious injury it is NOT now considered to be a prognostic indicator for recovery - it indicates the area of spinal cord affected by injury. A better prognostic indicator is presence or absence of deep pain sensation; and the rate at
which this returns.

Question 93

How do you localise spinal cord injuries of L4-S3, what signs may be seen?

Answer 93

Spinal segment lesion L4-S3
Depending on the severity of the injury, these cases will have paraparesis or paraplegia. Spinal reflexes will be normal in the forelimbs but absent or reduced in
the hind limbs.
In addition, for the more caudally situated lesions, lack of anal tone and urinary sphincter tone may be apparent, with urinary or faecal incontinence, and an easily expressed, flaccid bladder.

Question 94

What diagnostic imagine is required for spinal injuries?

Answer 94

Diagnostic Imaging
Advanced diagnostic imaging (MRI/CT) will generally be required for diagnosis and treatment planning. Radiography, if performed with care, can be helpful in the initial assessment of the emergency spinal cord case e.g. survey lateral radiographs may indicate the presence of a vertebral fracture or luxation. It is very important that any further patient movement is minimised if a fracture or luxation is confirmed

Question 95

What may radiography reveal in a patient with disco-spondylitis? What other signs will be seen?

Answer 95

A patient with disco-spondylitis may have radiographic evidence of lysis of vertebrae in the lumbo-sacral region- the patient may be pyrexic with localised pain and an accompanying urinary tract infection

Question 96

What are the prognostic indicators that can give an indication of the severity and progression of the spinal cord injury?

Answer 96

Prognostic indicators:
The prognosis for full recovery for animals with serious spinal cord injuries is guarded. Initial and ongoing assessment of the voluntary motor deficit, urinary
function and presence of deep pain sensation give an indication of the severity and progression of the spinal cord injury.

Question 97

What grading system can be applied to give an indication of the severity and progression of the spinal cord injury?

Answer 97

The following grading system can be applied (Bush, 2014):
Grade 1 - Pain only. Ambulatory with no other deficits noted.
Grade 2 - Tetra or paraparesis. Ambulatory with loss of proprioceptive function, weakness and ataxia.
Grade 3 - Tetra or paraparesis. Non-ambulatory, but evidence of voluntary movement in the limbs.
Grade 4 - Tetra or paraplegia. Non-ambulatory, with no evidence of voluntary movement in the limbs, deep pain sensation present. +/- Urinary function.
Grade 5 - Paraplegia. As above, with no evidence of deep pain sensation.

Question 98

How can spinal cord injuries affect the urinary bladder?

Answer 98

Depending on the nature and location of the spinal cord injury, animals may have altered urinary function: there may be reflex urination, urinary incontinence or urinary retention and overflow. Early assessment and appropriate management of urinary function is essential. The bladder of animals with reflex urination and urinary retention and overflow, may be harder to express than normal. Animals with disco-spondylitis may also have a urinary tract infection (UTI): UTI’s can also develop as a complication of spinal cord injury and associated recumbency.

Question 99

How do you handle, provide initial management and treat spinal cord injuries?

Answer 99

Handling of the patient
It is vital that the patient’s movement is restricted during hospitalisation.

Initial management
Following a full clinical examination +/- diagnostic imaging, a treatment plan will be made. The severity of the injury, poor prognosis or prolonged hospitalisation required may mean that euthanasia is required.

Treatment will be surgical or conservative (medical).
Surgical intervention may be necessary for stabilisation or decompression with fractures, luxations or intervertebral disc disease. Initial medical management usually consists of NSAID and opioid administration
combined with strict cage rest. Benzodiazepines may be used for muscle relaxation. The use of glucocorticoids/steroids is not recommended for spinal cord injuries but may be required for inflammatory conditions.
Animals with disco-spondylitis will require antibiotic therapy based on culture and sensitivity for a period of at least 6-8 weeks.

Question 100

What neurological function assessment should be carried out on a patient with a spinal injury following ongoing care? How often should this be carried out?

Answer 100

An assessment of neurological function should be made 1-2 x daily. This should include an assessment of the spinal reflexes (including the panniculus reflex),
proprioception and voluntary motor function. Deep pain sensation should be assessed, as appropriate, following consultation with a veterinary surgeon. A
validated pain scoring system should be used to monitor the patient’s progress.

Question 101

What body systems should be monitored if lesions are high up in the cervical area and why?

Answer 101

As lesions high up in the cervical area, may affect cardiac and respiratory function, it is important to be vigilant in monitoring of respiratory and cardiac function.

Question 102

How do you manage a recumbent patient’s urinary output?

Answer 102

Any recumbent patient (comatose, stuporous, spinal injury) may require an indwelling urinary catheter with a closed collection system - this requires appropriate
aseptic management. In all recumbent patients, the bladder should be regularly palpated to ensure it is not becoming over-full. The patient should be assessed for
any evidence of urine scald. For more information on urinary catheterisation

Question 103

What physiotherapy is required in a recumbent patient?

Answer 103

Patient will need to be turned with care every 2-4 hours to prevent decubitus ulceration and hypostatic pneumonia. Appropriate postural, passive and active
physiotherapy, under veterinary direction, will be beneficial at various stages throughout the patient’s recuperation e.g. coupage. Initial passive physiotherapy will encourage blood flow to the limbs helping to maintain muscle tone. Physiotherapy should be avoided where patients are at risk of seizuring and where unstable spinal trauma is present.

It is important to be aware of the challenges and potential complications associated
with nursing neurological patients- these can include depression, hypostatic
pneumonia, decubitus ulcers and urine scald.

Question 104

How can you manage a recumbent patients faecal output?

Answer 104

Faecal output may need to be managed- diarrhoea, faecal incontinence or constipation may occur. Enemas may be required.

Question 105

What can be the cause of brain injury or disease?

Answer 105

There are many causes of brain injury and disease. Clinical signs associated with brain disease may develop suddenly in spite of the underlying cause having been present for a longer period e.g. blindness secondary to an expanding brain tumour.
These include
1) Trauma
2) Inflammation (of the brain [encephalitis] or the meninges [meningitis] or both [meningoencephalitis]). This may be sterile or infectious in origin.
3) Congenital defects (e.g. cerebella hypoplasia)
4) Cerebral oedema
5) Vascular infarcts (‘stroke’)
6) Age related degeneration
7) Tumour
8) Epilepsy

Question 106

What two categories can head trauma be divided into?

Answer 106

Head trauma can be split into primary and secondary injury

Question 107

How does primary head injury occur and what does it result in?

Answer 107

Primary injury occurs through direct concussive forces e.g. road traffic collision, kick or fall. This results in
haemorrhage and direct neuron damage

Question 108

How does secondary head injury occur and what does it result in?

Answer 108

Secondary injury occurs in response to, and is a serious complication of, the initial insult. Inflammation with release of inflammatory mediators, including excitatory amino acids, leads to cerebral oedema,
decreased cerebral perfusion and cerebral hypoxia. This leads to brain swelling, increased intracranial pressure and further neuronal damage.

Question 109

What assessments should be carried out when triaging a patient with head trauma?

Answer 109

As will all emergency patients a brief, rapid history should be obtained with an initial assessment of the three major body systems (cardiovascular, respiratory, and neurological) any immediately life-threatening problems managed accordingly.
Further neurological assessment involves assessing mental status, brainstem reflexes and gait. The Modified Glasgow Coma Score (MGCS) can be used for
objective assessment

Question 110

What mental alertness would be considered an emergency?

Answer 110

Stupor and coma are considered to be emergencies

Question 111

Define the term alert?

Answer 111

Alert: aware of surroundings and responsive

Question 112

Define the term obtunded?

Answer 112

Obtunded: decreased awareness but reacts to stimuli

Question 113

Define the term stupor?

Answer 113

Stupor: decreased consciousness, difficult to rouse but responsive to strong stimuli

Question 114

Define the term coma?

Answer 114

Coma: unresponsive to any stimuli

Question 115

Define the term Opisthotonus?

Answer 115

Opisthotonus: Extreme hyperextended posture with increased extensor tone of the limbs and the neck

Question 116

Define the term Decerebrate rigidity?

Answer 116

Decerebrate rigidity:
opisthotonus with extensor rigidity of fore and hind limbs.
Animal is comatose; absent PLRs; pinpoint or dilated pupils. Poor prognosis: cerebral lesion

Opisthotonus: Extreme hyperextended posture with increased extensor tone of the limbs and the neck

Question 117

Define the term Decerebellate rigidity?

Answer 117

Decerebellate rigidity: opisthotonus with extensor rigidity of fore limbs. Animal usually conscious; PLR’s present. Cerebellar lesion.
Opisthotonus: Extreme hyperextended posture with increased extensor tone of the limbs and the neck

Question 118

What is a cushing reflex?

Answer 118

Cushing’s reflex: this is caused by increased intracranial pressure. Systemic hypertension arises in an attempt to maintain cerebral perfusion: this is accompanied by a reflex bradycardia.

Question 119

What is a significant alteration in consciousness likely to be associated with?

Answer 119

Significant alteration in consciousness (e.g. coma) is likely to be associated with brainstem disease

Question 120

What could any sudden alteration in a patients mentation be due to?

Answer 120

Any sudden alteration in a patient’s condition could be due to brain herniation, arising secondary to increased intracranial pressure, and is a very serious complication which should be anticipated in animals presenting with brain injuries

Question 121

What is Transtentorial herniation of the forebrain? and what can this lead to?

Answer 121

Transtentorial herniation of the forebrain compresses the midbrain, leading to altered consciousness; loss of the pupillary light reflexes; meiosis followed by
mydriasis; decerebrate rigidity and hyperventilation. Prompt recognition of these signs is required if the patient is to have any chance of survival.

Question 122

What can Herniation through the foramen magnum cause and what is the prognosis?

Answer 122

Herniation through the foramen magnum causes central vestibular signs, coma, altered respiratory rate and pattern and altered heart rate, rhythm and blood
pressure. This is a very serious condition that is unlikely to be reversible.

Question 123

What are the clinical signs of a traumatic brain injury?

Answer 123

1) Altered mentation
2) Seizuring
3) Nystagmus
4) Miosis/mydriasis
5) Anisocoria
6) Absent PLRs
7) Tetraparesis/plegia; hemiparesis/plegia; decerebrate rigidity; opisthotonus; altered muscle tone
8) Photophobia

Question 124

What type of diagnostic imaging should a patient with suspected or confirmed traumatic injury ideally have?

Answer 124

Any animal with suspected or confirmed traumatic brain injury, with compatible signs, should ideally have advanced prompt diagnostic imaging (CT/ MRI) to allow
for accurate diagnosis and treatment planning.

Question 125

What are many of the clinical signs with traumatic brain injury associated with?

Answer 125

Many of the clinical signs described are associated with an increase in intracranial pressure (ICP). Raised ICP is life-threatening (irreversible neuron damage) with brain herniation being a serious consequence - consequently it requires to be recognised promptly

Question 126

What clinical findings can intracranial pressure provisionally be diagnosed?

Answer 126

Raised ICP can be provisionally diagnosed by patient
assessment, based on several clinical findings, (oedema of the optic disc; pulsating retinal vessels; elevated blood pressure and bradycardia). Noting bradycardia in any patient that has a brain injury/ disease is significant. It is not possible to accurately measure intracranial pressure in veterinary patients but it can be estimated using transcranial Doppler measurements.

Question 127

What is the normal intracranial pressure in dogs and cats?

Answer 127

Normal ICP in cats and dogs is 5 – 10mmHg

Question 128

What predominant factor controls blood flow to the brain and what is this dependent on?

Answer 128

When dealing with head trauma patients it is important to maintain an adequate blood supply to the brain. Cerebral perfusion pressure (CPP) is the predominant
factor which controls blood flow to the brain and is dependent on mean arterial pressure (MAP) and intracranial pressure (ICP) as shown in the following equation:
CPP = MAP – ICP

Question 129

What can an increased blood pressure suggest in a patient with traumatic brain injury?

Answer 129

Normally cerebral blood flow is maintained within narrow limits. However, in a brain trauma patient these control factors are lost and cerebral blood flow becomes directly proportional to systemic blood pressure. Most cases of head trauma present
with increased blood pressure, suggesting corresponding increased intracranial pressure. Associated with increased ICP is bradycardia which is an important clinical parameter to note. This combination of high blood pressure and low heart rate is termed the Cushing’s reflex.
However, there are also cases where hypotension can be present resulting in decreased cerebral perfusion, ischaemia and cerebral oedema.
Regular monitoring, noting any trends, of blood pressure and heart rate is important in the clinical work up of these patients

Question 130

Why is important to measure blood gas in patient with traumatic brain injury?

Answer 130

Respiration rates may become depressed therefore measurement of blood gases is important in monitoring the patient’s progress.

Question 131

Why is oxygen therapy often necessary in patients with head trauma?

Answer 131

As with all trauma patients, oxygen therapy is often necessary- ventilation may be reduced due to direct head trauma or damage to nerves supplying the respiratory muscles .The patient must not be stressed by oxygen administration as this may further increase ICP. Methods that may cause sneezing or coughing should be e.g. nasal prongs

Question 132

How can hyperventilation assist with decreasing intracranial pressure?

Answer 132

Hyperventilation has previously been considered a means of decreasing ICP as the reduced PaCO2, caused by mechanical hyperventilation, results in cerebral vasoconstriction thus aiding reduction of ICP. This, however, will result in cerebral hypoxia which is associated with decreased chance of survival in human patients. Hyperventilation should only be used as a short-term measure if there is imminent risk of brain herniation. Instead the aim should be adequate oxygenation with maintenance of the PaCO2 within the normal range (35-40 mmHg).

Question 133

How can patient positioning assist with decreasing intracranial pressure?

Answer 133

Another procedure aimed at reducing ICP is patient positioning. Raising the patient’s head by 15-30 degrees above the pelvis, aids venous drainage from the brain, thus reducing ICP. The patient’s neck should not be flexed as this will decrease drainage.
The whole patient should be elevated using a tilting table or a rigid board. The jugular vein should not be used for blood sampling.

Question 134

Shoud fluid therapy in a patient with intra cranial pressure be restricted to reduce cerebral oedema?

Answer 134

Mean arterial pressure should be maintained between 70 and 110 mmHg - fluid therapy is generally indicated accompanied with blood pressure monitoring. Fluid
therapy should never be restricted for fear of causing cerebral oedema. There is more likelihood of problems arising with cerebral hypoxia (secondary to decreased
perfusion) than with IVFT. It is, however, essential to avoid both over and under perfusion and to monitor the patient carefully to maintain euvolaemia. Isotonic fluids
are generally appropriate for circulatory support- hypotonic fluids are contraindicated as they increase the likelihood of cerebral oedema.

Question 135

How does hypertonic saline assist in a patient intracranial pressure from a trauma?

Answer 135

Hypertonic saline may be used in the management of both hypovolaemia and ICP.
Hypertonic saline is a concentrated solution of sodium chloride (7.5%) that also draws fluid from the interstitium and intracellular space into the intravascular space.
This results in an abrupt increase in intravascular volume (correcting any hypotension) and reduces the intracranial pressure.

Question 136

How does mannitol assist in a patient intracranial pressure from a trauma?

Answer 136

Mannitol may also be used in the management of increased ICP. Mannitol is an osmotic diuretic and draws fluid out of oedematous cells within the body, including the brain. Mannitol may be used at 0.5-2g/kg, as a 15-25% solution given over 20-30 minutes - it should only be used in patients that are cardiovascularly stable.

Question 137

What is the dose of mannitol?

Answer 137

Mannitol may be used at 0.5-2g/kg, as a 15-25% solution given over 20-30 minutes

Question 138

Are corticosteroids indicated in patients with a traumatic brain injury?

Answer 138

The use of corticosteroids is not recommended in animals with traumatic brain injury

Question 139

What will analgesia choice in a patient with a traumatic brain injury be affected by?

Answer 139

Opiates are the drug of choice for analgesia- the choice of opiate will be affected by several factors e.g. the potential risk of increased ICP associated with vomiting following morphine administration

Question 140

What patient parameters should be monitored in a patient with a traumatic brain injury?

Answer 140

It is important that continuous monitoring is provided, noting any trends, to allow rapid instigation of emergency procedures as required.
In addition to monitoring TPR, blood pressure, perfusion parameters, demeanour and pain levels, specific neurological assessment should be performed. Respiratory rate and pattern should be carefully assessed as any alteration in these could be
associated with patient deterioration.
Patient mentation should be assessed as1) Normal (alert)
2) Depressed
3) Obtunded
4) Stuporous
5) Comatose

Question 141

How can the cranial nerves be assessed and monitored in a patient with a traumatic brain injury?

Answer 141

The patient posture should be assessed noting any abnormal positions e.g. opisthotonus.
The presence of nystagmus, pupillary light reflexes (PLRs), oculo-cephalic reflexes, pupil size and eye position should be noted. Many head trauma patients will have unequal pupil size (anisocoria). Widely dilated pupils that are unresponsive to light (fixed and dilated pupils) are an extremely poor prognostic indicator and suggesting significant brainstem damage. The progression from constricted to dilated pupils can
therefore indicate a worsening of the condition, suggestive of brainstem herniation.
Initially ICP, can stimulate the oculomotor nerve (CNIII) leading to pupillary constriction. With increasing ICP, the brain is displaced caudally. The hind brain and
brain stem are telescoped into the proximal spinal column putting further pressure on the oculomotor nerve and stopping it from working (normally causes miosis).
Consequently, the pupils become dilated and unresponsive. Further herniation of the brain, through the foramen magnum, places further pressure on nerves in the spinal cord leading to limb abnormalities e.g. decerebrate rigidity. As previously discussed,
with decerebrate rigidity, the patient will show opisthotonus, fore and hind limb extensor rigidity and respiratory depression.

Question 142

How can oxygenation be assessed in a patient with a traumatic brain injury and in which situation would this be especially important?

Answer 142

Oxygenation should be assessed, ideally using blood gases, or by pulse oximetry if blood gas analysis is not possible- especially if the patient is comatose and
mechanical ventilation is required. It is important to also ensure PaCO2 levels are maintained within a range of 35-40mmHg. Hyperventilation due to mechanical ventilation leads to reflex cerebral vasoconstriction which would cause cerebral hypoxia. This situation should be avoided unless the emergency prevention of brain herniation is being attempted.
It is vital to remember that as ICP increases, blood pressure tends to increase and the heart tends to decrease.

Question 143

What signs are usually seen in patients with meningitis and/or meningoencephalitis?

Answer 143

Patients with meningitis and/or meningoencephalitis may present with neck pain, photophobia and pyrexia, with varying levels of neurological dysfunction. Patients
are commonly depressed and disorientated

Question 144

What test is used to diagnose meningitis/ meningoencephalitis? What is the contraindication to performing this test?

Answer 144

Cerebro-spinal fluid (CSF) collection and analysis may be indicated in the diagnosis of meningitis/ meningoencephalitis.
There is a significant risk of brain herniation if CSF collection is attempted in patients with increased ICP, therefore this should be recognised and managed prior to CSF sampling

Question 145

Describe the technique for cerebrospinal fluid collection?

Answer 145

Technique for CSF collection
This is an act of veterinary surgery which cannot be legally delegated to a veterinary
nurse.
The patient will need to be anaesthetised and placed in lateral or sternal recumbency with the muzzle elevated. A ~ 5 cm square area of skin is clipped using the midline, occipital protuberance at the base of the skull and the wings of the atlas as landmarks.
During collection, the head is flexed so that the nose is at right-angles to the neck and parallel to the table top. It is important to ensure the ET tube is not kinked or
obstructed. Monitoring of the heart rate, pulse quality and blood pressure is also important during CSF collection. Because of the risk of hypoventilation due to patient position, oxygenation should be monitored closely. The site for insertion of the spinal needle (1.5 to 3 inch/ 3.8-6.4cm/ 20-22 gauge) is mid-way between the

Question 146

What is vestibular disease?

Answer 146

Vestibular disease is the name given to any condition which affects the balance centres. There are two main areas which deal with balance- a central brain site (medulla and cerebellum); and the peripheral semi-circular canals and the vestibule of the inner ear. Disease in either area, or the nerve which
transmits impulses from the inner ear to the cerebellum (the vestibulocochlear nerve/cranial nerve VIII), can result in balance disorders.

Question 147

What are the causes of vestibular disease?

Answer 147

Causes of vestibular disease include
1) Inner/middle ear disease
2) Cerebellar disease
3) Infection (e.g. viral [distemper, FIP], parasitic [Toxoplasma], fungal
[Cryptococcus neoformans])
4) Infarction (‘strokes’)
5) Toxins (e.g. metronidazole toxicity affecting the cerebellum/medulla)
6) Metabolic
7) Neoplasia
8) Idiopathic (unknown cause typical in older dogs and cats) -this is the commonest cause of vestibular disease in dogs.

Question 148

What are the clinical signs of vestibular disease?

Answer 148

Clinical signs
Vestibular disease is often rapid in onset.
Clinical signs can include
1) Nystagmus
2) Head tilt
3) Rolling
4) Circling
5) Ventral strabismus (may not be noted until head is elevated)
6) Inability to stand
7) Wide-based stance or altered gait: hypermetria or dysmetria.
8) Vomiting and nausea
Inner ear disease may be an extension of middle ear disease- associated clinical signs may be present e.g. Horner’s syndrome and dysfunction of cranial nerve VII
(facial nerve). Horner’s syndrome would be very unlikely to occur in central vestibular disease.

Question 149

What can horners syndrome arise due to and what are the signs?

Answer 149

Horner’s syndrome arises due to interruption of the sympathetic nervous supply to the eye. Signs of Horner’s syndrome include miosis, enophthalmos, protrusion of the third eyelid and ptosis of the upper eyelid. As a result of facial nerve dysfunction,
the patient may also have keratoconjunctivitis sicca (KCS/ dry eye). If nystagmus is present it tends to be horizontal or rotational with the slow phase towards the side of the head with the lesion. Additionally, the direction of the nystagmus does not
change when the head is tilted.

Question 150

How do you diagnose vestibular disease and what can aid the differentiation between central from peripheral vestibular disease?

Answer 150

Neurological examination can aid differentiation of central from peripheral vestibular disease, thus helping to establish a cause and prognosis. The prognosis for central vestibular disease is poorer than for peripheral vestibular disease. Establishing a cause of central vestibular disease will need further investigation e.g. MRI With diseases of the inner and middle ear, there may be Horner’s syndrome and damage to the facial nerve.

Question 151

What is suggestive of vestibular disease affecting the medulla and cerebellum?

Answer 151

With diseases of the medulla and cerebellum there may be other signs suggestive of brain disease such as altered mentation and seizures- often the patient has a widebased stance and sways from side to side. Nystagmus will often change when the head is tilted and can be in any direction. Cranial nerve damage may be present on the same side as the lesion and may affect any cranial nerve from V-XII.

Question 152

What diagnostic imaging can confirm middle and inner ear disease causing vestibular signs?

Answer 152

With middle and inner ear disease, radiography, CT or MRI of the tympanic bullae may show abnormalities

Question 153

What type of treatment is required for peripheral and central vestibular disease?

Answer 153

For peripheral vestibular disease the treatment is usually symptomatic and supportive. Treatment for central peripheral disease depends on the cause

Question 154

What initial medication may be required for patients with vestibular signs?

Answer 154

Initial medication
If seizuring has occurred / is occurring then anti-convulsant therapy may be required (e.g. diazepam or phenobarbital) as discussed previously. The patient should be kept in a quiet environment with dimmed lighting.
Many patients may also be vomiting/feeling nauseous (motion sickness) and so may benefit from the administration of anti-nausea or anti-emetic medications e.g. metoclopramide or maropitant. Middle/ inner ear infections will require appropriate treatment e.g. systemic broad spectrum antibiotics.
Middle ear polyps may require surgery.

Question 155

What important considerations are there when managing a patient with vestibular signs?

Answer 155

Initial management
Most patients will need strict cage rest, minimal excitement and may need to be kept in a kennel which is padded to reduce trauma.
Care should also be taken to ensure the patient can feed properly. Many cannot position themselves to do this and so may require assisted feeding.

Question 156

What ongoing medication is usually required for a patient with inner ear disease displaying vestibular signs?

Answer 156

Antibiotics may need to be continued for a period of 4-6 weeks in cases of inner ear disease.

Question 157

Why are telephone triage of ocular problems difficult?

Answer 157

Telephone triage of ocular problems is very difficult as the eyes have limited responses to insult: a red eye, increased lacrimation and blepharospasm could be
due to conjunctivitis, a penetrating foreign body or anterior uveitis. Ideally all patients should be seen as soon as possible. Rapid recognition of the cause and appropriate management is needed to minimise patient discomfort and prevent irreversible eye damage. If an owner reports that their animal may have a foreign body, they should be advised to come immediately to the veterinary practice and must NOT attempt to remove this themselves. Advice should be given on how to transport the patient so that it does no further harm to itself.

Question 158

Why should patients with ocular problems be handled carefully and what should part of the triage process include?

Answer 158

Patients should be handled carefully and any procedure which may increase intraocular pressure should be avoided - if the patient is stressed by handling, sedation may be the preferred option. Most ocular emergencies are very painful and there is a risk of the condition worsening due to self-trauma- an Elizabethan Collar should usually be applied. The patient should be in a quiet environment, in dimmed light and will need to be observed continually. As part of the triage assessment, a rapid, visual examination of the eye(s) should be performed, noting any abnormalities, especially those that may require rapid veterinary intervention e.g. prolapse, ruptured globe. First aid measures may be required at this stage.

Question 159

What does an ophthalmological examination involved and what equipment is needed?

Answer 159

Once the patient’s condition permits it, the veterinary surgeon will require to perform a thorough examination of the eye, including beneath the third eyelid where foreign bodies e.g. grass seeds may be located. Eye examinations are best performed in
dimmed but not entirely dark rooms.
Clinical assessment involves visual examination aided by equipment such as a pen torch, an indirect ophthalmoscope, a direct ophthalmoscope, a tonometer and ultrasound.
Additional equipment that will often be required for ophthalmic examinations includes:
1) Fluorescein pipettes or paper strips
2) Schirmer Tear Test strips
3) Topical local anaesthetic pipettes (proxymetacaine and amethocaine) - these should be stored in the fridge
4) Tropicamide ‘Mydriacyl®’: this is used to dilate the pupil for ocular examinations

Any products in pipettes are intended for single use only, as they contain no preservative. Prolonged or repeated application of local anaesthetic can cause
corneal damage.

Question 160

What is a corneal ulcer?

Answer 160

A corneal ulcer is present when an area of cornea has lost its outer epithelium and some of the underlying stroma. Corneal ulcers are a result of damage to the
transparent cornea- they are common and can vary significantly in severity. The deeper the ulcer is the more serious it is; especially if it occupies a large area. As the cornea forms part of the outer wall of the eye, damage affects the integrity of the eye- rupture of the globe is a very serious possible complication of corneal
ulceration. Corneal ulcers can be simple or complicated- some heal well and others have delayed healing. During the initial emergency presentation, the healing potential of the ulcer is generally unknown, unless the patient has a history of corneal ulceration. As with all wounds, however, the initial management can have an impact on subsequent healing so it is important to have a good understanding of corneal anatomy and physiology.

Question 161

What can corneal ulcers occur due to?

Answer 161

Corneal ulcers can occur due to

1) Trauma: abrasion/laceration/surface or foreign bodies
2) Conformation/ inherited tendency e.g. brachycephalic animals
3) Infection e.g. FHV or Chlamydophila in cats; Pseudomonas
4) Decreased tear production keratoconjunctivitis sicca (dry eye)
5) Entropion (inward rolling of the eyelid allowing hairs to rub on the corneal surface)
6) Chemical splashes

Identifying the cause, where possible, ensures appropriate treatment can be
provided

Question 162

What are some signs of ocular discomfort?

Answer 162

Signs of ocular discomfort could include

1) Blepharospasm
2) Increased lacrimation
3) Enophthalmos
4) Protrusion of the third eyelid
5) Photophobia
6) Reluctance to be handled

Question 163

What are some signs of a corneal ulcer?

Answer 163

There are numerous pain receptors (nociceptors) within the cornea which are stimulated by corneal injury. Corneal ulceration is a very painful, particularly with
shallow ulcers as there are more nociceptors closer to the surface.
Signs of ocular discomfort could include
1) Blepharospasm
2) Increased lacrimation
3) Enophthalmos
4) Protrusion of the third eyelid
5) Photophobia
6) Reluctance to be handled
Additionally, oedema may be seen around the ulcer as a blue/grey opacity as fluid penetrates the normally dehydrated stroma. In some cases, blood vessels may be seen growing across the, normally avascular, surface of the cornea (corneal neovascularisation). Clinical signs of an associated reflex, anterior uveitis may be
present, in addition, with miosis and pain secondary to ciliary muscle spasm

Question 164

How can you prevent self trauma in a patient with ocular discomfort?

Answer 164

It is important to prevent the patient doing more damage by self-trauma- an Elizabethan Collar should usually be applied. The patient should be nursed in a quiet environment, in dimmed light and will need to be observed continually.

Question 165

How do you diagnose a corneal ulcer?

Answer 165

Confirmation of the presence, size, depth of the ulcer and presence of underrun tissue requires administration of fluorescein (new pipette or impregnated paper strip).
An open pipette should not be used as bacteria can grow in fluorescein. Most information about fluorescein uptake by the ulcer can be gained by examination with
a blue light source.
N.B. Descemet’s membrane (the inner endothelial layer of the cornea) does not stain with fluorescein. A non- staining central area in a deep ulcer is a significant finding and veterinary attention should be sought immediately as the eye may be close to rupture.

Question 166

What initial medication is usually required in a patient with a corneal ulcer?

Answer 166

The medication that may be used will depend on the cause, size and depth of the ulcer.
Analgesia will be required- NSAIDs and/ or opiates. Opiates may be required if there is an accompanying anterior uveitis.
As with all wounds, a moist environment promotes wound healing - artificial tears +/- ocular lubricants will often be used. Other topically applied products, however, may interfere with the healing process due to being foreign material or causing corneal
irritation.
As infection delays healing, topical antibiotic preparations may be indicated.

Question 167

What medications/products should be avoided in a patient with a corneal ulcer?

Answer 167

Certain products should NOT be used as they are damaging to the cornea or delay healing. Topical corticosteroids should be avoided as they will delay healing; suppress the immune system thus predisposing to bacterial infection; and enhance
collagenase activity which may predispose to the development of a ‘melting ulcer’.
Topical local anaesthetics should not be used for analgesia as they damage the cornea.

Question 168

How do you treat superficial corneal ulcers?

Answer 168

Superficial ulcers
Most superficial ulcers can be managed symptomatically and should heal within a few days. Occasionally some of these ulcers will not heal due to lifting of the edge of the cornea away from its basement membrane. This can be seen using
fluorescein- the dye can be seen to under-run the edges of the ulcer. In these cases, debridement of the underrun tissue will be required. Additional procedures to stimulate wound healing e.g. grid/ punctate keratotomy may be performed under general anaesthetic to stimulate healing.

Question 169

Why are deep corneal ulcers serious?

Answer 169

Deep ulcers
These are more serious as there is a greater risk of the globe perforating. Secondary infection is very serious especially with Gram negative bacteria such as
Pseudomonas spp. which produce collagenase enzymes. Collagenase enzymes breakdown the stroma of the cornea, predisposing to melting ulcers which rapidly destroy the cornea increasing the size and the depth of the ulcer

Question 170

How do you treat deep corneal ulcers?

Answer 170

Deep ulcers
These are more serious as there is a greater risk of the globe perforating. Secondary infection is very serious especially with Gram negative bacteria such as
Pseudomonas spp. which produce collagenase enzymes. Collagenase enzymes breakdown the stroma of the cornea, predisposing to melting ulcers which rapidly destroy the cornea increasing the size and the depth of the ulcer. Appropriate antibiotic therapy will be required in these cases- this should be based on identification of the bacteria, culture and sensitivity (e.g. gentamycin for Pseudomonas).
Anti-collagenases will also be indicated- these help to counteract the collagenase activity as well as promoting corneal repair. Acetylcysteine (5%) is an option but usually autologous (the patient’s own) serum or plasma is used.

In addition to analgesia, a mydriatic e.g. atropine 0.5-1% may be required to overcome iris spasm if anterior uveitis is also present.

Question 171

How do you get plasma/serum to use in a patient with a deep corneal ulcer?

Answer 171

Blood is obtained from the patient and put into an EDTA, heparin or serum gel tube.
After centrifugation, the serum/plasma is separated and put into a sterile container and refrigerated. It can then be applied very frequently (every 30 minutes to 2 hours) as indicated. The serum/plasma should be handled carefully to prevent microbial
contamination.
Some clinicians use acetyl cysteine in the management of deep/ melting ulcers.

Question 172

What are the surgical options for a corneal ulcer?

Answer 172

Surgical options may include application of veterinary contact lenses or conjunctival flaps/grafts or, less frequently now, eyelid flap surgical techniques
This is especially likely if a descemetocoele forms

Question 173

What is A descemetocoele?

Answer 173

A descemetocoele is a sign of impending globe rupture- when the ulcer has eroded through the outer cornea down to the corneal endothelium (Descemet’s membrane), which then protrudes through
the ulcer. As descemet’s membrane does NOT stain with fluorescein, it is very significant to have a very deep ulcer with a central non-staining area especially if a membrane looks to be protruding through the ulcer.

Surgical options may include application of veterinary contact lenses or conjunctival flaps/grafts or, less frequently now, eyelid flap surgical techniques
This is especially likely if a descemetocoele forms

If a descemetocoele is suspected, the veterinary surgeon should be alerted IMMEDIATELY and the animal should not be handled to avoid causing rupture of the globe.

A sudden increase in discomfort and aqueous discharge from the eye of a patient with a deep ulcer could suggest that the eye has ruptured. This requires immediate veterinary attention.

Question 174

What can chemical burns of the cornea be caused by? What are the potential complications? and what treatment is initially required?

Answer 174

Chemical burns
These can be caused by both acid and alkaline substances - alkali causes more damage to the cornea. Corneal ulceration, sloughing and perforation
are possible complications. Continuous lavage, using warmed sterile saline over 30 minutes, is recommended with the aim of returning the corneal
surface to neutral pH. The pH can be checked using urine dipsticks. Pain management is also essential as is prevention of self-trauma.

Question 175

What advice could be given to an owner with a pet that has a ocular foreign body? What treatment when arriving in an emergency could be given?

Answer 175

Foreign bodies
These may be periocular, free or embedded. They will cause much discomfort with the patient often trying to rub frantically at the area, potentially causing more harm.
An Elizabethan collar should be applied promptly- the owner could be advised to wrap their pet carefully in a large towel to travel to the surgery.
If the foreign body (FB) is still present but not penetrating, it may be dislodged by flushing with sterile 0.9% saline via a syringe attached to an IV catheter. Some FBs can be securely lodged in or on the cornea- removal should not be attempted until the patient can be safely anaesthetised.
If the foreign body has not penetrated through the full thickness of the cornea, management should be as for a deep corneal ulcer, once removed.
Under GA, leakage of aqueous humour may occur as the FB is removed- this indicates full thickness corneal penetration which requires surgical management as
for a deep corneal ulcer/descemetocoele e.g. conjunctival flap.
Additional analgesia, infection control and management of associate anterior uveitis will be required

Question 176

What ongoing medication and management should be given a patient with ocular trauma following initial treatment?

Answer 176

Ongoing medication and management
In all cases, ongoing analgesia should be started as ulcers are painful. In addition, an Elizabethan collar is essential to prevent the patient from rubbing the eye which can worsen the condition or precipitate rupture of the globe. Over-zealous restraint can also result in rupture of the globe, where deep ulcers are present, therefore the handling of such patients should be careful.
If the cornea does rupture this may be clearly obvious or may be highlighted by application of fluorescein dye which will form rivulets of stain from the hole (the
Seidel test). Where a conjunctival flap/graft surgery has been performed, regular ongoing assessment of the eye should be performed: wound issues, excessive
discharge or signs of pain should be assessed

Question 177

What is anterior uveitis?

Answer 177

This is inflammation of the anterior structures of the globe i.e. the iris and ciliary body

Due to iris and ciliary muscle spasm, anterior uveitis is painful and there is usually marked constriction of the pupil.

Question 178

What can anterior uveitis be caused by?

Answer 178

1) Infection, either local or systemic
2) Trauma ( including ocular surgery)
3) Displaced/ruptured lens/cataract
4) Neoplasia
5) Reflex secondary to e.g. corneal ulceration
6) Immune-mediated
7) Idiopathic (unknown cause).

Question 179

What are the common causes of anterior uveitis in cats?

Answer 179

It may be a single episode or there may be recurrent episodes, especially in cats.
Infectious causes are common in cats e.g. feline infectious peritonitis (FIP), feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) infections.

Question 180

What are the common causes of anterior uveitis in dogs?

Answer 180

It may be a single episode or there may be recurrent episodes, especially in cats.
In dogs it is generally secondary to other causes e.g. trauma, corneal ulceration or lens luxation.

Question 181

What are the clinical signs of anterior uveitis?

Answer 181

Clinical signs
These are often inflammatory and pain-related e.g. blepharospasm, increased lacrimation, miosis and episcleral congestion. The iris may appear abnormal in
colour and shape (especially if the uveitis is chronic); there may be corneal oedema, hypopyon or hyphaemia

Question 182

How do you diagnose anterior uveitis?

Answer 182

This is generally based on the clinical signs especially miosis and pain.
Anterior uveitis may be secondary to other eye problems- it is good practice to assess tear production (Schirmer Tear Test) and exclude corneal ulceration
(fluorescein)
Both tonometry and gonioscopy are useful to rule out glaucoma, another cause of a red painful eye. Glaucoma may arise secondary to anterior uveitis- constriction of the pupil interferes with the flow of aqueous humour, decreasing drainage.
In anterior uveitis, the intra-ocular pressure (IOP) is often less than normal- unless there is secondary glaucoma in which case the IOP will be increased.
Tonometry results may show IOP less than 10 mmHg (normal range 15-25mmHg).
Gonioscopy involves the use of a small diffracting lens placed onto the corneal surface. This allows the clinician to examine the anterior chamber and the drainage angle to try to identify an underlying cause. The eye must be pre-treated with ophthalmic local anaesthetic first.
Finally, anterior uveitis may not be the only clinical sign the patient may be demonstrating, as many of the diseases which lead to anterior uveitis affect the
animal systemically. Careful examination of the rest of the patient may aid diagnosis; combined with haematology, biochemistry, serology, and virology e.g. FIP/FeLV and FIV.

Question 183

What is the range of intraocular pressure of a patient with anterior uveitis?

Answer 183

In anterior uveitis, the intra-ocular pressure (IOP) is often less than normal- unless there is secondary glaucoma in which case the IOP will be increased.
Tonometry results may show IOP less than 10 mmHg (normal range 15-25mmHg).

Question 184

What serious complication can occur secondary with anterior uveitis?

Answer 184

A serious complication of anterior uveitis is that secondary to inflammation and inflammatory chemicals, the iris becomes ‘sticky’- this could lead to iris adherence either to the lens behind it (forming posterior synechiae) or to the cornea in front of it
(forming anterior synechiae). The latter is more serious as it can block the drainage angle of the eye and so result in glaucoma.

Question 185

What initial medication is required for anterior uveitis?

Answer 185

Initial medication
A serious complication of anterior uveitis is that secondary to inflammation and inflammatory chemicals, the iris becomes ‘sticky’- this could lead to iris adherence either to the lens behind it (forming posterior synechiae) or to the cornea in front of it (forming anterior synechiae). The latter is more serious as it can block the drainage angle of the eye and so result in glaucoma. Therefore, the use of a mydriatic (a drug which dilates the pupil) is necessary. Atropine drops are generally used topically 2-3 times daily: to aid pain management by overcoming ciliary spasm; and to maintain dilation of the pupil to prevent glaucoma. If, however, glaucoma is already present atropine is contra-indicated; it should be used with caution in patients with KCS as it will decreased tear production further (Hartley, 2013). Alternatively, tropicamide or adrenaline (1% solution) can be instilled onto the cornea 3 times daily.
If an underlying cause is identified, this should be the focus for treatment. Otherwise, controlling the inflammation and pain is the priority: NSAIDs, analgesics, corticosteroids and immunosuppressants, may all be used in the management depending on the situation. Corticosteroids would be contraindicated if the anterior uveitis was secondary to corneal ulceration.

Question 186

What ongoing care is required for anterior uveitis?

Answer 186

Where there is an underlying cause such as a viral disease or lens luxation the prognosis is more guarded. Currently the viral conditions are not curable and lens
removal is a specialist operation.
Possible complications of anterior uveitis, as discussed, include pain, adhesions (synechiae) both anterior and posterior, corneal neovascularisation and glaucoma.
Regular assessment for any of these should be included in patient monitoring.

Question 187

What is uaully the cause of Proptosis/prolapse and rupture of the globe?

Answer 187

Typically this occurs due to trauma such as road traffic accidents- there is also a breed predisposition with brachycephalic breeds being more commonly affected

Question 188

What is it important to consider when a patient presents with Proptosis/prolapse and rupture of the globe in an emergency?

Answer 188

If the animal has had a traumatic event e.g. RTA, it is important not to be diverted by the prolapsed eye and overlook other potentially life-threatening problems. There may be an associated traumatic brain injury which would be of far greater clinical significance.
Following prolapse there may be irreversible eye or optic nerve damage, meaning that enucleation will be required. PLR and menace reflexes can be tested- lack of response carries a poor prognosis for recovery of vision.

Question 189

What is the initial management of a patient with Proptosis/prolapse and rupture of the globe in an emergency?

Answer 189

Initial management
The aim of emergency treatment is to protect the eye from any further damage, limit swelling, minimise desiccation, prevent self-trauma and control pain. The prognosis for the eye is improved if it is replaced as soon as possible- so the patient should not be fed and veterinary attention should be sought. The prolapsed/proptosed eye should be kept moist and clean. Debris can be gently washed out of the eye using sterile 0.9% saline- as long as tolerated by the patient.
Handling should be kept to a minimum; and self-trauma prevented by careful application of an Elizabethan collar. Thereafter the eye must be kept moist using an
ocular lubricant e.g. Lacrilube® or K-Y jelly ® to prevent desiccation.
Replacement of the globe in the orbit should NOT be attempted in a conscious patient- the owner should be informed of this. Full assessment and cleaning of the
globe will be required under anaesthesia, once the patient’s general condition is suitably stable. Drugs which may increase IOP e.g. ketamine should be avoided. Pain assessment and analgesia will be required.

Question 190

How do you prepare a patient for ocular surgery and globe replacement?

Answer 190

Preparation for surgery
For either globe replacement or enucleation careful preparation around the eye should be performed.
Both eyes needs to be protected with sterile ocular lubricant; minimal clipping should be performed to prevent small hair fragments adhering to the globe
The area should be cleaned with sterile 0.9% saline, diluted povidine-iodine (0.2%) or diluted chlorhexidine gluconate (0.05%). Chlorohexidine diacetate should not be used for preoperative ocular preparations due to the high degree of tissue toxicity.
Globe replacement
A lateral canthotomy may be required to replace the globe followed by suturing together of the eyelids for 7-10 days. A small gap between the lids allows topical
medication to be applied to the globe e.g. lubricant and antibiotics.

Question 191

What post-operative care does a patient with Proptosis/prolapse and rupture of the globe require?

Answer 191

The patient will need to be closely observed for pain, infection and swelling. An Elizabethan collar will be needed to prevent self-trauma.
Careful cleaning of the periocular area is necessary to remove tissue fluids or discharge.

Question 192

What are the causes of conjunctivitis?

Answer 192

Causes of conjunctivitis include:
1) Infection (particularly Chlamydophila spp. and Herpes virus in cats and
Distemper virus in dogs)
2) Trauma
3) Allergies e.g. atopy
4) Corneal ulceration
5) Contact (chemical) irritants
6) Environmental irritants e.g. wind, grass
7) Foreign bodies
8) Secondary bacterial infection due to keratoconjunctivitis sicca
9) Immune-mediated

Question 193

What is conjunctivitis?

Answer 193

Conjunctivitis is inflammation of the conjunctiva- the double – layered mucous membrane, epithelial layer that lines the eyelids and attaches at scleral/corneal
junction. Conjunctivitis is not a diagnosis but a sign of some conjunctival trauma/irritation. It may occur alone; or as part of another ocular or systemic problem

Question 194

What are the clinical signs of conjunctivitis?

Answer 194

Clinical signs
These include conjunctival hyperaemia, blepharospasm, pain, inflammation, increased tear production / ocular discharge and chemosis.

Question 195

How do you diagnose conjunctivitis?

Answer 195

Diagnosis
Clinical signs may be suggestive of conjunctivitis although the causative agent may not be obvious. Conjunctivitis is not usually very serious but it is important to ensure there is not a more serious associated condition e.g. uveitis, glaucoma, corneal
ulceration. In all cases, a full ophthalmic examination, Schirmer tear test and fluorescein administration will be required for complete assessment e.g. bacteriology
and cytology may be required from conjunctival swabs and smears. In cats, conjunctival swabs may be submitted in appropriate transport medium for
Chlamydophila ssp.; oropharyngeal swabs, also in viral transport medium, may be used for Calicivirus and Herpes virus identification.

Question 196

What is the initial management and treatment for conjunctivitis?

Answer 196

Initial management
Cleansing and lubrication of the conjunctivae, with sterile 0.9% saline flush and ocular lubricants, will limit further damage and provide protection. Full examination and cleansing, may require sedation/general anaesthesia. An Elizabethan collar should be used in more severe cases to prevent further self-inflicted damage.
Treatment is symptomatic and dependant on the cause e.g. artificial tears and immunosuppressant for KCS; corticosteroids for allergic conjunctivitis.

Question 197

What is glaucoma?

Answer 197

Glaucoma is a condition that leads to rapid onset retinal degeneration and blindness, as well as being very painful. In cats and dogs this is secondary to increased intraocular pressure (IOP) (Oliver, 2014). Glaucoma is more often recognised in dogs than cats- cats eyes are relatively more resistant to glaucomatous changes.
Increased IOP results from decreased drainage of aqueous humour from the anterior chamber at the drainage angle. Aqueous humour is produced continually at the ciliary body, which supports the lens, and drains at the ciliary cleft, the area created
by the junction of the cornea and iris. Glaucoma is caused by failure of drainage of aqueous humour- resulting in an increase in the volume within the globe. This causes increased intraocular pressure, which can be intensely painful and leads to blindness due to rapid, irreversible damage of the delicate intraocular structures e.g. retina
Glaucoma can be primary or secondary:

Question 198

What produces aqueous humour and what does it do?

Answer 198

Aqueous humour is produced continually at the ciliary body, which supports the lens, and drains at the ciliary cleft, the area created by the junction of the cornea and iris

Question 199

What is primary glaucoma due to in dogs?

Answer 199

In dogs, primary glaucoma is due to an inherited, bilateral malformation of the drainage angle at the ciliary cleft- goniodysgenesis. There are two that may occur in primary glaucoma- open angle and closed angle. With both, inadequate drainage of aqueous humour may occur. Whilst the malformation is
congenital, decreased aqueous drainage does not usually start to occur till later in life. Breeds recognised to be affected by primary glaucoma are listed in, and can be assessed under, the BVA, The Kennel Club (KC) and the International Sheep Dog Society (ISDS) eye scheme. malformations

Question 200

What species does primary glaucoma tend to affect most?

Answer 200

Dogs

Question 201

What are the two types of malformations in primary glaucoma in dogs?

Answer 201

There are two that may occur in primary glaucoma- open angle and closed angle. With both, inadequate drainage of aqueous humour may occur. Whilst the malformation is congenital, decreased aqueous drainage does not usually start to occur till later in life

Question 202

What breed of cats are most likely affected by primary glaucoma?

Answer 202

Rarely, primary glaucoma will occur in cat- certain breeds e.g. Burmese and Siamese can be affected

Question 203

What can be the causes of secondary glaucoma?

Answer 203

Secondary glaucoma arises when another ocular condition leads to blockage of the drainage angle. Secondary causes of glaucoma include:

1) Anterior uveitis
2) Neoplasia
3) Lens luxation
4) Hyphaema
5) Intraocular surgery
6) Pigmentation

Question 204

What does Glaucoma in cats secondary to anterior uveitis, generally arise due to?

Answer 204

Glaucoma, in cats, secondary to anterior uveitis, generally arises as a result of infection with FIP, FeLV, FIV or toxoplasma. There are other causes of glaucoma in cats

Question 205

At what intraocular pressure measurement will clinical signs usually be seen?

Answer 205

Clinical signs will usually be seen when the IOP is > 25 mmHg in dogs and > 30 mmHg in cats.

Question 206

What are the clinical signs of acute glaucoma?

Answer 206

In acute glaucoma, there may not be as many clinical findings as with chronic glaucoma. Usually only one eye is affected with glaucoma initially, even if there is a
bilateral congenital abnormality.
All the signs of a sore, possibly, blind eye are likely to be present- blepharospasm, increased lacrimation and a ‘red eye’. The pupil will usually be fixed and dilated with absent or decreased PLR and menace reflex. The cornea may have a ground-glass/ hazy appearance and there is often marked epi-scleral congestion. The affected eye will sometimes feel more tense/rigid than the unaffected eye, due to increased IOP, although this is not very sensitive means of assessment.
There are various factors, including age, that affect the ability of the eye to be distended. Glaucoma may be acute or chronic depending on the timecourse and underlying cause. If it is slowly progressive, there may be few obvious clinical signs until the condition is advanced. The clinical findings will depend on
how long the condition has been present and whether there is an underlying cause.
Pain is a consistent feature especially in acute cases or end- stage, enlarged, congested eyes.

Question 207

What are the signs of chronic glaucoma?

Answer 207

There are various factors, including age, that affect the ability of the eye to be distended. Glaucoma may be acute or chronic depending on the timecourse and underlying cause. If it is slowly progressive, there may be few obvious clinical signs until the condition is advanced. The clinical findings will depend on
how long the condition has been present and whether there is an underlying cause.
Pain is a consistent feature especially in acute cases or end-stage, enlarged, congested eyes.
With chronic glaucoma, additional signs may be present due to the gradual stretching of the globe by the increased volume of aqueous humour. There may also
be buphthalmos, protrusion of the third eyelid, linear opacification of the cornea due to endothelial tears (Haab’s striae) and caudal displacement of the lens. There may be central corneal ulceration secondary to poor tear distribution.
Additional findings may be present if the glaucoma is secondary e.g. lens luxation, cataract, intraocular haemorrhage, evidence of neoplasia etc.
An end-stage, chronically glaucomatous eye may have gradually degenerated and be decreased in size- phthisis bulbi.

Question 208

How do you diagnose Glaucoma?

Answer 208

This is based upon clinical signs and measurement of the intraocular pressure (IOP).
A tonometer is used to measure IOP- different types are available using different physics principles. An applanation/ indentation tonometer- Tono-pen™/Schiotz can be used; or a rebound tonometer- Tonovet™.
With an applanation/ indentation tonometer measurement of intraocular pressure requires the tonometer to be placed onto the corneal surface therefore a topical local anaesthetic needs to be applied to the eyes a few minutes prior to testing. For
Schiotz tonometry, the animal needs to be positioned so that the footplate of the vertically held, tonometer can sit horizontally across the surface of the cornea. The digital tonometer does not require this level of restraint, and is therefore easier to use.
The rebound tonometer does not required the application of local anaesthesia to the
surface of the eye.
It is important to adopt a good technique for recording IOP- the reliability of the readings can be affected by various factors. Correct maintenance and use of the
equipment is important. If the patient struggles or is agitated the readings may be falsely elevated. Occlusion of the jugular vein when restraining will lead to falsely elevated readings.
Normal IOP readings are around 15-25 mmHg although there are various factors that can affect this (e.g. age, time of day) - readings in excess of 35mmHg require
emergency treatment.
As severe, irreversible damage to the retina and optic nerve occurs quickly, acute glaucoma is a true emergency requiring prompt attention.
Gonioscopy can be used to visualise the drainage angle and assess the structures of the anterior chamber. This involves placing a small diffracting lens onto the patient’s cornea, following administration of local anaesthetic.
Ultrasound may be used to image the interior of the eye and show evidence of neoplasia or lens luxation.

Question 209

What is the aim of emergency treatment in a patient with glaucoma?

Answer 209

In acute cases, the aim of emergency treatment is to decrease IOP, before there are irreversible ocular changes, and manage the pain (Oliver, 2014). Prompt
identification of a potential underlying cause is also important.
In chronic cases, where vision is already likely to be affected, pain management is the priority

Question 210

What is the management of acute glaucoma?

Answer 210

A rapid decrease in IOP is required, especially if the IOP is > 35 mmHg- this may be achieved by using an osmotic diuretic such as mannitol- although increasingly prostaglandin analogues may be used, as they are very effective, easy to administer and there is less risk of side-effects.
Latanoprost and travatan are prostaglandin analogues that increase the drainage of aqueous humour- they cause profound miosis. These drugs are increasingly used, where available, instead of or, in conjunction, with mannitol for management of acute glaucoma as they are considered to be superior to other treatments. They are contraindicated if there is anterior uveitis or complete lens luxation, although may be used in the management of lens subluxation. Latanaprost
should not be used in cats and there is no current information on the use of travatan in cats.
An intravenous infusion of 1-2 g/Kg of mannitol is administered over a period of 20-30 minutes- an improvement should be seen after one hour. Water should be withheld immediately following administration before being gradually reintroduced.
The dose may be repeated, if the IOP has not decreased to < 30 mmHG, once or twice after 4-8 hours, as long as the patient is not dehydrated and serum electrolytes can be measured.
Extreme care must be taken with mannitol NOT to cause volume overload; fluid and electrolyte abnormalities may arise secondary to treatment.
Side effects from mannitol can include dehydration- it should be used with extreme caution or be avoided in dehydrated, renally or cardiovascularly compromised
patients. Oral glycerol is an alternative if mannitol is not available.
Carbonic anhydrase inhibitors, (brizolamide and dorzolamide) reduce the rate of aqueous humour production thus IOP. They are generally used in dogs and cats in the long–term medical management of glaucoma but can also be used in the acute management stage Miotics e.g. 1-2% pilocarpine drops may be used to decrease IOP by stimulating contraction of the ciliary body (although other preparations are now preferred): pulling the iris away from the drainage angle so encouraging drainage of aqueous humour. Pilocarpine is less likely to be used since the increased use of prostaglandin analogues and carbonic anhydrase inhibitors. It should not be used if a patient has
anterior uveitis or lens luxation and is not recommended in cats.
Pilocarpine is a parasympathomimetic drug- it can cause bradycardia, hypersalivation, vomiting and diarrhoea.
Analgesia is important as glaucoma is intensely painful. The choice of analgesic will depend on the animal’s clinical presentation and severity of the patient’s pain. Dual therapy analgesia (e.g. opioid plus systemic NSAID) may be used (Oliver, 2014).
NSAIDs should be avoided, as ever, if the patient has received corticosteroids, has renal disease/ GI disease or is dehydrated.
In addition it is important to avoid the use of ketamine or any other drug that could increase IOP.
Atropine is also contraindicated due to its pupillary effects.

Question 211

What is the management of chronic glaucoma?

Answer 211

Chronic management
Carbonic anhydrase inhibitors reduce the rate of aqueous humour production thus IOP- they are generally used in dogs and cats in the long–term medical management of glaucoma. Topical CAIs (brizolamide and dorzolamide) are preferred to oral
preparations (dichlorphenamide) as there is less likelihood of side effects such as vomiting, anorexia and sedation.
Beta-blockers (e.g. timolol maleate) decrease aqueous production and can be used in the management of canine and feline glaucoma. As they cause miosis, they
should not be used in anterior uveitis or lens luxation.
Treatment of the underlying cause is required in patients with secondary glaucoma e.g. uveitis, lens luxation or neoplasia. Surgery may be indicated for some conditions e.g. lens luxation. Enucleation may be required in an end-stage, painful eye. Other surgical options exist for decreasing aqueous production or increasing aqueous drainage. These are not, however, emergency procedures so are not discussed
here.
Ongoing assessments of IOP and pain is required- initially hourly until IOP reduces below 30mmHg and thence once every 3-4 hours until the patient is stabilised.
There are additionally several surgical options although these are not likely to be performed in the emergency setting

Question 212

Define the following:

Hemiparesis

Clonus

..
Blepharospasm

Syncope

Tonus

Opisthotonus

Tetraparesis

Schiff-Scherrington posture

Answer 212

The correct answer is: Hemiparesis → Weakness in two limbs on one side of the body,
Clonus → Involuntary, regular, rhythmic muscle contractions,
Blepharospasm → Rapid blinking of the eyelids often in response to ocular pain or irritation; or spasm of the muscles making it hard to open the eyelids,
Syncope → A collapse / faint, Tonus → Increased extensor tone of muscles,
Opisthotonus → Strong contraction of the extensor muscles of the neck and back - results in arching of the back and hyperextension (backward arching) of the head and neck - often with extension of the fore limbs., Tetraparesis → Weakness in all four limbs,
Schiff-Scherrington posture → Increased forelimb extensor tone secondary to a serious injury from T3-L3

Question 213

Which cranial nerve is the vagus?

Select one:

a. IV
b. VII
c. I
d. X

Answer 213

The correct answer is: X

Question 214

What is a serious clinical finding in a patient at risk of increased intra-cranial pressure?

Select one:

a. Pulse deficit
b. Sinus rhythm
c. Bradycardia
d. Tachycardia

Answer 214

The correct answer is: Bradycardia

Question 215

An animal with increased intra-cranial pressure should be positioned in

Select one:

a. Ventral recumbancy with the entire body and head raised by 30 degrees
b. Ventral recumbancy with the head raised 30 degrees to the body
c. Dorsal recumbancy with the entire body and head raised by 30 degrees
d. Lateral recumbancy with the head raised 30 degrees to the body

Answer 215

The correct answer is: Ventral recumbancy with the entire body and head raised by 30 degrees

Question 216

Which terms are used in the assessment of patient mentation?

Select one:

a. Sleepy, dull, obtunded, lethargic and normal
b. Comatose, dull, depressed, timid and normal
c. Sleepy, stuporous, depressed, obtunded and normal
d. Comatose, stuporous, obtunded, depressed and normal

Answer 216

The correct answer is: Comatose, stuporous, obtunded, depressed and normal

Question 217

Anisocoria means

Select one:

a. Pupils are of different sizes
b. Both pupils are of equal size
c. Both pupils are constricted
d. Both pupils are dilated

Answer 217

The correct answer is: Pupils are of different sizes

Question 218

Fluoroscein can be used to:

Select one:

a. Dilate the pupil
b. Measure aqueous humour volume
c. Anaesthetise the cornea
d. Demonstrate corneal ulceration

Answer 218

The correct answer is: Demonstrate corneal ulceration

Question 219

Uveitis is inflammation of the:

Select one:

a. Retina and tapetum lucidum
b. Iris, choroid and ciliary body
c. Cornea and sclera
d. Lens and ciliary body

Answer 219

The correct answer is: Iris, choroid and ciliary body

Question 220

A tonometer assesses

Select one:

a. Dilation of the pupil
b. The drainage angle
c. Size of the optic disc
d. Intra-ocular pressure

Answer 220

The correct answer is: Intra-ocular pressure

Question 221

Normal intra-ocular pressure for the dog is:

Select one:

a. 5-15mmHg
b. 35-45mmHg
c. 25-35mmHg
d. 15-25mmHg

Answer 221

The correct answer is: 15-25mmHg

Question 222

Signs of vestibular disease can be caused by which of the following?

Select one:

a. Disease of the medulla
b. Disease of the cerebellum
c. Disease of the semi-circular canals
d. All of the above

Answer 222

The correct answer is: All of the above

Question 223

All of the following are signs of Horner’s syndrome, except:

Select one:

a. Ptosis
b. Nystagmus
c. Miosis
d. Enophthalmos

Answer 223

The correct answer is: Nystagmus

Question 224

Which of the following stages of seizure would most likely be the longest lasting?

Select one:

a. Pre-ictal stage
b. Post-ictal stage
c. Prodromal stage
d. Ictal stage

Answer 224

The correct answer is: Post-ictal stage

Question 225

The menace response reflex assesses cranial nerves:

Select one:

a. VII and IX
b. IV and II
c. II and VII
d. III and VIII

Answer 225

The correct answer is: II and VII

Question 226

Of the following, which is the recommended concentration of dextrose to administer to a patient intravenously to avoid phlebitis?

Select one:

a. 10%
b. 25%
c. 50%
d. 2.5%

Answer 226

The correct answer is: 2.5%

Question 227

The formulae for calculating cerebral perfusion (CP) is:

Select one:

a. Intracranial pressure x Mean arterial pressure
b. Mean arterial pressure – Intracranial pressure
c. Mean arterial pressure ÷ Intracranial pressure
d. Intracranial pressure + Mean arterial pressure

Answer 227

The correct answer is: Mean arterial pressure – Intracranial pressure

Question 228

Using a spinal cord injury grading system, a non-ambulatory patient with tetra or paraparesis in addition to some voluntary movement, would be graded as a:

Select one:

a. 4
b. 3
c. 5
d. 2
e. 1

Answer 228

The correct answer is: 3

Question 229

The stage of a seizure best described as a subtle change in mood or behaviour would be called:

Select one:

a. Prodromal stage
b. Pre-ictal stage
c. Ictal stage
d. Post-ictal stage

Answer 229

The correct answer is: Prodromal stage

Question 230

Breathing difficulties could be present in a patient with a with a spinal cord lesion between:

Select one:

a. T3-T7
b. L3-L7
c. T8-L3
d. C1-T2

Answer 230

The correct answer is: C1-T2

Question 231

A 6.8 kg dog is placed on a propofol 10mg/ml CRI for status epilepticus. The dose is 3mg/kg/hr for four hours. Calculate the dose required.

Answer 231

The correct answer is: 8.16 ml