Neurology Flashcards
Introduction, review of NEU1, neurological examination, head tilt
What signs would be seen in the limbs of an animal with a cranial lesion CNS?
Forelimbs and hindlimbs UMN signs, i.e. spastic paralysis
What signs would be seen in the limbs of an animal with a lesion at the level of C1-C5?
Forelimbs and hindlimbs UMN i.e. spastic paralysis
What signs would be seen in the limbs of an animal with a lesion at the level of C6-T2?
Forelimbs LMN (flaccid paralysis), hindlimbs UMN (spastic paralysis)
What signs would be seen in the limbs of an animals with a lesion at the level of T3-L3?
Forelimbs normal, hindlimbs UMN (spastic paralysis)
What signs would be seen in the limbs of an animal with a lesion at the level of L4-S3?
Forelimbs normal, hindlimbs LMN (flaccid paralysis)
What are the roles of the forebrain?
- Mentation
- visual/auditory processing
- Motor initiation
- Sensory perception
Describe the signs of forebrain syndrome
- Altered mental state
- Central blindness/deafness
- Inatention
- Normal to paretic gait (large circles towards side of lesion)
- Abnormal postural reactions (contralateral)
- Abnormal movement/postures (head pressing)
- Seizures
- +/- papilledema
What is papilledema?
Swelling of the optic nerve head, may be seen with forebrain swelling
Describe the signs of cerebellar lesions
- Ataxia
- Wide based stance
- Dysmetria (normal strength)
- intention tremor (generalised and eyes)
- Extensor hypertonus
- May have absent menace, opisthotonus, vestibular signs
What is opisthotonus?
Muscle spasm leading to backwards arching of the head, neck and spine
Describe the signs of a diencephalic lesion
- UMN signs in all 4 limbs or contralateral
- Mental depression
- Optic nerve deficit
- Endocrine autonomic deficits
- Inappetance
Describe the signs of a midbrain lesion
- UMN signs in all 4 limbs or contralateral
- Mental depression
- Ipsilateral oculomotor (III) signs
- May have hhperventilation and head pressing
Describe the signs of a pontomedullary lesion
- UMN signs in all 4 limbs (ipsi or contralateral)
- Postural reaction deficits
- Cranial nerve IV-VII deficits
- Altered mental state
Compare the signs of a central and a peripheral vestibular lesion
- In both: head tilt, asymmetric ataxia, nystagmus
- Only in central: positional nystagmus (+/- other central nerve deficits, decreased proprioception, paresis)
- +/- in either: Horner’s, facial paralysis
Outline how the sign/time graph
- Trauma and infection initially get worse, then get better with time (signs increase, then decrease with time)
- Neoplastic and degenerative signs worsen with time
- Anomalous diseases do not change over time so signs are constant
What is the main difference between botulism and tetanus?
Botulism is flaccid paralysis, tetanus is spastic paralysis
How does tetanus develop?
Entrance of bacteria through broken skin and colonise wound, but tentus will not develop in every would colonised by C. tetani - requires an anaerobic environment
where does the tetanus toxin have its effect?
Effect in the spinal cord, affecting the interneurons
Describe the treatment of tetanus
- Vaccination
- Flush wound in order to make it aerobic (more effective than antibiotics, need to get rid of the wound)
- Antibiotics, antitoxin, antibodies
How does botulism develop?
Ingestion of the toxin, commonly from bad tinned food or spoiled hay
How does botulism has its effect?
Action in the lower motor neurons, affecting the neuromuscular junction
Describe the treatment of botulism
- Antibiotics no effect as only the toxin is ingested
- Need to consider source of ingestion and remove
How is botulism different in horses/foals compared to other animals?
Clostridium botulinum bacteria can be ingested and can colonise the intestinal system, so not just toxins causing disease
What is the main value of assessing proprioception in an animal presented with lameness?
Identify as fracture or neurological
What lesions would lead to proprioceptive deficits?
Damage to cerebellum, forebrain, brainstem, spinal cord
What are the main signs that would distinguish a forebrain lesion from another brain region?
With forebrain, would expect seizures, circling, head turn, behavioural changes
Compare the outflow of the parasymathetic and sympathic nervous system
- Para out via cranial nerves mostly
- Sympathetic out via thoracolumbar and back up via vagosympathetic trunk through middle ear
What tests would you perform in an animal presented with asymmetry of the face and why?
- Suggests cranial nerve VII affected
- Test with palpebral response
- Schirmer tear test (VII) controls lacrimation
What does a unilaterally constricted pupil suggest?
Loss of sympathetic innervation to that eye
Explain the use and appearance of contrast medium on MRI
- Gadalinium, not iodine
- IV administration
- Usually will not cross BBB
- Shows up white on T1 weighted images
Which tests are used to assess CNII?
(Optic)
- Conscious vision (tracking)
- Menace (also VII)
- Visual placing
How is CNIII function assessed?
(Oculomotor)
- PLR (also tests II): direct and indirect
- Anisocoria
- Fixating response (also II)
- Strabismus
How is CNV function assessed?
- Palpebral reflex
- Corneal reflex
- Skin sensation
- Temporal/masseter muscle mass
What is the function of cranial nerve VI?
Abducens nerve, eye movement (motor)
How is CNVII function assessed?
(Facial)
- Facial muscle symmetry
- Lacrimal gland function
- Nasal gland function
How is CNVIII function assessed?
(Vestibulocochlear)
Hearing
- Nystagmus (also III, IV, VI, VIII)
How is CNIX function assessed?
(Glossopharyngeal)
Swallowing (gag)
How is CNX function assessed?
(Vagus)
- Laryngeal function (bark)
- Gastrointestinal function
How is CNXI function assessed?
(Accessory)
Neck position/tone
How is CNXII function assessed?
(Hypoglossal)
- Tongue position and tone
Describe a normal mental status
Alert, with normal response to environmental stimuli
Describe a confused and disorientated mental status
Responding to environmental stimuli in an appropriate manner
Describe a depressed mental status
Drowsiness, inattention and less responsive to environmental stimuli
Describe a stuporous mental status
State of unconsciousness with reduced responses to external stimuli, but can be roused by a painful stimulus
Describe a comatose mental status
state of unconsciousness with absence of response to any environmental stimuli including pain
What is indicated by a head tilt vs a head turn?
- Head tilt indicates vestibular
- Head turn indicates forebrain
- Both present with circling towards the side of the lesion
What is the function of cranial nerve I?
Olfactory, smell, sensory
What is the function of cranial nerve II?
Optic, vision, sensory
What is the function of cranial nerve III?
Oculomotor, eye movement, motor
What is the function of cranial nerve IV?
Trochlear, eye movement, motor
What is the function of cranial nerve V?
Trigeminal, 3 branches, facial sensation and integrity of masticatory muscles, sensory and motor
What is the function of cranial nerve VI?
Abducend, eye movement, motor
What is the function of cranial nerve VII?
Facial, facial expression, taste, functionality of rostral 2/3rd of tongue, lacrimation and salivation, sensory and motor
What is the function of cranial nerve VIII?
Auditory/vestibulocochlear, hearing and vestibular function, sensory
What is the function of cranial nerve IX?
Glossopharyngeal, pharyngeal sensory and muscular action, sensory and motor
What is the function of cranial nerve X?
Vagus, purely parasympathetic, laryngeal sensation and motor control, sensory and motor
What is the function of cranial nerve XI?
Accessory, controls neck muscles, motor
What is the function of cranial nerve XII?
Hypoglossal, controls intrinsic tongue muscles, motor
What is the afferent and efferent supplies that facilitate the palpebral response?
Afferent: trigeminal
Efferent: facial
What are the afferent and efferent supplies for the PLR?
Afferent: optic nerve
Efferent: oculomotor nerve
What are the afferent and efferent supplies for the menace response?
Afferent: optic nerve
Efferent: facial nerve
What brain regions are involved in the menace response?
Conscious visual pathways, contralateral visual cortex, contralateral motor cortex, ipsilateral cerebellar hemisphere
Describe the pathways of conscious vision
- Light into eye, singal conducted by optic nerve to optic chiasm
- Fibres cross and one travels to ipsipateral and one to contralateral lateral geniculate nucleus via optic tract
- Optic radiation into visual cortex from the LGN
Define strabismus and what nerves are involved?
Abnormal static position of the eye
Generated by lesions affecting CN III, IV, and VI
What does a “dolls eye” movement suggest?
Physiological nystagmus
Describe the signs of Horner’s syndrome in the small animal, horse and cow
- Ptosis, meiosis, enophthalmus in most
- Horse: ptosis and ipsilateral facial sweating
- Cow: ipselateral dry nose
What is assessed in the neurological examination of the trunk?
- Spinal pain
- Perineal reflex
- Bladder function
- Muscle tone/atrophy
- Tail carriage
- Aim to identify focal regions of pain or dysfunction
Where should the panniculus reflex be demonstrable in the dog?
From the scapula to the pelvis
What is assessed in the neurological examination of the limbs?
- Proprioception
- Sensation
- Segmental reflexes
- Muscle mass and tone
Describe the assessment (method, nerve assessed) of the myotatic reflexes of the extensor carpi radialis (ECR)
- Percuss muscle belly of ECR
- Reflex extension of the carpus
- Tests radial nerve
Describe the assessment of the myotatic reflexes (method, nerve assessed) of the biceps
- Percuss finger/thumb pressing into tendon of insertion of the biceps muscle
- Reflex contraction of muscle generates flexion of elbow, more common felt as increased tension in tendon of insertion
- Movement of skin over muscle belly/visible contraction
- Tests musculocutaneous nerve
Describe the assessment of the myotatic reflexes (method, nerve assessed) of the triceps muscle
- Percuss finger/thumb which are pressing onto tendon of insertion of triceps
- Reflex contraction of trips generates reflex extension of elbow, increased tension intendon of insertion, movemet of skin over muscle belly/visible contraction
- tests radial nerve
Describe the assessment of the myotatic reflexes (method, nerve assessed) of the patella
- Percuss straight patellar tendon, resulting in reflex extension of stifle
- Tests the femoral nerve
Describe the assessment of the myotatic reflexes (method, nerve assessed) of the cranial tibial muscle
- Percuss muscle belly of cranial tibial muscle
- Reflex flexion of hock
- Tests sciatic nerve
How is the lumbosacral spinal cord assessed?
- Perineal reflex (stimulation of perineal region should elicit winking or constriction of anal sphincter)
- Anal sphincter should exhibit good tone
- Good tail tone and function with no reduction in tail carriage
Compare the appearance of upper and lower motor neuron lesions
- UMN: increased/normal reflexes, high tone, slow muscle atrophy
- LMN: rapid muscle atrophy, reduced reflexes, low tone
Compare the neurological examination of dogs and cats
- Cats same as dogs in terms of tests that can be performed and interpretation of tests
- Cats often do not tolerate restraint and manipulation required
- Cats will often tolerate 3 tests, so choose 3 that are most likely to confirm suspicions re. lesion localisation and severity
List the differentials for a cat with sudden onset left sided head tilt with no history of trauma or previous related clinical problems, and no other clinical signs
- Most likely peripheral, central would show other cranial nerve deficits
- Otitis media/interna
- Idiopathic vestibular disease
- Pharyngeal polyps
- Oral neroplasia
- Toxicity
- Inflammatory or traumatic brainstem lesion
- Ear mites
- Hypothyroidism
List the differential diagnoses for a cat presented with central vestibular disease
- Vascular lesions
- Brainstem neoplasia
- FIP (dry form)
- Toxoplasmosis
- GME
- Thymine deficiency
- Forebrain lesion
Outline the diagnosis of a peripheral vestibular problem in cats
- Full neuroexam
- Aural exam, esp. for OM, ear parasites
- Advanced imaging for OI, neoplasia, thymine deficiency, vascular disease
- Pharyngeal examination for polyps
- CSF or serology for toxoplasmosis, but common infection that does not commonly cause problems
- CSF for GME
- Idiopathic vestibular diagnosis by exclusion
- Leave and watch for improvement/worsening
List the degenerative causes of central vestibular disease in dogs
- Lysosomal storage disorders
- Neurodegenerative diseases
List the anomalous causes of peripheral and central vestibular disease in dogs
- Central: Chiari-like malformation
- Congenital vestibular disease
List the metabolic causes of vestibular disease in dogs
Hypothyroidism (peripheral vestibular)
List the nutritional causes of vestibular disease in dogs
Thiamine deficiency (central vestibular)
List the inflammatory causes of peripheral and central vestibular disease in dogs
- Central: meningoencephalitis
- Peripheral: otitis media/interna, nasopharyngeal polps
List the idiopathic causes of peripheral and central vestibular disease in dogs
- Central: arachnoid cysts
- Peripheral: idiopathic vestibular disease
List the toxic causes of peripheral and central vestibular disease in dogs
- Central: metronidazole
- Peripheral: aminoglycosides, topical iodophors, chlorhexidine and others
List the traumatic causes of peripheral and central vestibular disease in dogs
- Central: head trauma
- Peripheral: trauma to middle or inner ear
List the vascular causes of vestibular disease in dogs
Cerebrovascular disease (central), lungworm most common cause of vascular disease
List the differential diagnoses for a dog presented with progressive left sided head tilt, which has progresseed over preceding month
- Vascular (lungowrm most common cause)
- Brain neoplasia
- Otitis media
- Hypothyroidism
- Autoimmne
- Lysosomal storage disorders
- Neurodegenerative diseases
- Toxins
- Ear parasites
- Neospora caninum
- Polyps (rare in dogs)
- GME (common)
Outline a diagnostic plan for a dog with progressive left sided head tilt, which has progresseed over preceding month
- Thorough history
- Observation, full general and full neuro exam
- Otoscopy
- CSF, MRI for neoplasia with inflammation or infectious with inflammation
- Serology (lungowrm)
- CBC, urinalysis, thyroid panel: primary bleeding disorder (also haemorrhages elsewhere), metabolic disease
- Radiography of tympanic bullae for OI
- Refer for CT, MRI
- Trial clindamycin for Toxo/Neospora
List the differential diagnoses for a rabbit presented with central vestibular dysfunction
- Bacterial infection
- Listeriosis
- Herpesvirus encephalitis
- Visceral larval migrans
- Encephalotozoon
- Toxoplasmosis
- Neoplasia
- cerebrovascular accident
- Degenerative changes
- Trauma
- Rabies (not UK)
- Toxins
List the differential diagnoses for a rabbit presented with peripheral vestibular dysfunction
- Bacterial otitis interma/media e.g. Pasteurella multocida, Bordatella bronchiseptica, Pseudomonas aeruginosa, Staphylococcus aureus
- Toxins e.g. aminoglycosides
- Idiopathic vestibular syndrome
List the differential diagnoses for paresis/paralysis in rabbis
- Vertebral fracture/luxation
- Spondylosis
- osteoarthritis
- Intervertbral disc disease
- encephalitozoonosis
- Toxoplasmosis
- Splay leg
- Hypovitaminosis A
- Neoplasia
- Ulcerative pododermatitis
Outline the approach to the diagnosis of a rabbit presented with sudden onset left sided head tilt
- Swab and culture for infection of ear canal
- Once stabilised, sedate and x-ray of base of skull for inner ear and vestibular canal
- Blood test for E. cuniculi infection (IgG and IgM antibodies)
- CT scan
Outline the treatment of a rabbit with sudden onset left sided head tilt
- Stabilise, ensure eating and drinking, treat gut stasis
- Anti-inflammatory and antibiotics
- E. cuniculi treat with 28 day course of fenbendazole, but will not reverse neurological signs
Outline the advice that should be given to an owner with a rabbit with E cuniculi
- isolate negative rabbits from positive
- Can be zoonotic
- Can infect cats and cause neurological and ophthalmic disease
- Treat all rabbits prophylactically with fenbendazole in feed, implement good hygiene and routine disinfection, raise food bowls and bottles
What is the main cause of head tilt in sheep and cattle?
Listerial encephalitis due to Listeria monocytogenes
What are the differentials for head tilt in sheep and cattle
- Sheep: polioencephalomalacia, coenurosis (Gid), vestibular disease (OM/OI)
- Cattle: coenurosis, vestibular disease due to OM/OI
List the common clinical signs of listeriosis in cattle and sheep
- Anterior uveitis (more important in cows)
- Placentitis, abortion (more important in sheep)
- Pneumonia
- Neonatal septicaemia ( more important in sheep)
- Meningeal encephalitis (more important in cows)
- Nystagmus
- Head tilt
- Loss of menace response
