Brain Conditions Flashcards
What are the two types of vestibular disease?
Peripheral VD
Central VD
What are the common clinical signs of Vestibular disease
head tilt
circling
falling to the affected side
Nystagmus (slow phase to the affected side)
What are the clinical signs of peripheral VD?
NO CP deficits or paresis
No depression
Facial nerve paralysis and Horner’s maybe
Horizontal/rotary nystagmus
What is the cause of peripheral VD?
ear infection
What are the clinical signs of central VD?
Tetra or hemiparesis
Depression
other cranial nerves affected
Nystagmus - horizontal rotary and vertical can be elicited by head movement and eyes can move in different directions
What is the cause of central VD?
Neoplasia Encephalitis hypothyroidism metronidazole aminoglycoside toxicity RMSF ehrlichia cryptococcus blastomyces toxoplasma neosporum thiamine deficiency GME thromboembolism septic emboli
Feline Idiopathic vestibular disease
unknown etiology associated with circling and falling with spontaneous remission after 3-4 weeks
Canine geriatric vestibular disease
middle aged to older dogs with a permanent head tilt. There is no treatment
Congenital peripheral vestibular disease
delayed development of the sensory receptors sometimes causing deafness
Seen in GSD, beagles, Doberman, Siamese, and Burmese
Paradoxical Central Vestibular Syndrome
lesions of the cerebellum causing lack of inhibition of the vestibular nucleus on the side of the lesion causing head tilt, circling, and falling to the OPPOSITE side
Where would the proprioceptive deficits be located with Paradoxical Central Vestibular Syndrome
on the same side as the cerebellar lesion
Cerebellum
coordinates motor activity and help maintain equilibrium and control posture
Clinical signs of cerebellar disease
wide based stance
truncal ataxia
intention tremor
dysmetria
Dysmetria
condition of improper measuring of distance during movement
Hypermetria
over-reaching
hypometria
under-reaching
decerebellate rigidity
severe lesions of the cerebellum lead to extensor rigidity of neck muscles resulting in dorsiflexion of the neck with extension of the thoracic limbs and flexion of the pelvic limbs
Decerebrate rigidity
midbrain lesions that cause opisthotonus with extension of all 4 limbs
Shiff Sherrington Syndrome
rigid extension of the thoracic limbs with severe spinal cord injuries between T2 and L6/7 due to the damage of the nerve connecting the pelvic and thoracic limbs
What causes cerebellar hypoplasia in cats?
intrauterine infections with panleukopenia parvovirus
Clinical signs of cerebellar hypoplasia in cats
truncal ataxia
tremor
dysmetria
What is the treatment for cerebellar hypoplasia in cats
NO TREATMENT
What is responsible for cerebellar hypoplasia in dogs?
Parvovirus
Cerebellar abiotrophy
premature death of neurons due to disruption of the metabolic processes int he cells
What viruses cause cerebellar infections?
Distemper
Canine herpes
FIP
What are the two types of cerebellum neoplasia?
Primary
Secondary
Common name for Corticosteroid responsive tremor syndrome
Shaker Dog Disease
Clinical signs of Corticosteroid responsive tremor syndrome (Shaker Dog Disease)
Tremors in all 4 limbs and head that get worse with exercise or excitement and resolve when the animal sleeps
Treatment of Corticosteroid responsive tremor syndrome (Shaker Dog Disease)
Glucocorticoids
What are other causes of tremors?
Fear
Hypomyelination
tremerogens (mycotoxins from old dairy food)
Other toxins
Orthostatic tremor : shivering while bearing weight
head bobbing
old dog hind limb tremors
Scotty Cramp (episodic muscle hypertonicity)
deficiency of serotonin inhibitory neurotransmitter and a prostaglandin abnormality
Clinical signs of Scotty Cramp (episodic muscle hypertonicity)
abduction of the thoracic limbs and then pelvic stiffness after exercise
Treatment of Scotty Cramp (episodic muscle hypertonicity)
Fluoxetine (“Prozac”)
What breed has Episodic falling?
Cavalier King Charles Spaniels
Clinical signs of Episodic falling
pelvic and thoracic limb hypertonicity
Treatment of Episodic falling
Clonazepam
Depression
decreased responsiveness
Stupor
unresponsive and arousable with painful stimuli
Coma
unresponsive and unarousable
Hydrocephalus
dilation of the ventricular system in the brain due to impeded flow of CSF due to neoplasia, subarachoid hemorrhage or meningitis or excessive excretion of CSF
What breed have hydrocephalus?
Toy, small, and brachycephalic breeds
Clinical signs of hydrocephalus
altered mental status slow learners seizures ventrolateral strabismus domed skull open fontanels
Diagnosis of hydrocephalus
Ultrasound
CT/MRI imaging
CSF COLLECTION RESULTS IN HERNIATION!
Treatment of Hydrocephalus
Shunts
What are two important neoplasia of the brain?
Meningiomas
Gliomas
What are the most common primary tumors of the brain?
Lymphomas
Gliomas
Clinical signs of a brain tumor
Changes in behavior
circling
seizures
Diagnosis of brain tumors
CT
MRI
Treatment of benign superficial tumors
Surgical removal
How do you treat a meningioma in a dog?
Surgical removal
Radiation after surgery
What is the treatment for solitary meningioma in a cat?
surgery
What drug can be used to give a good quality of life to an animal with a tumor?
Mannitol
What is the prognosis for a meningioma in a dog?
Poor
What is the prognosis for a meningioma in a cat?
If encapsulated can be a good prognosis
Clinical signs of brain herniation
Increased ICP depressed non-responsive or slowly responsive pupillary light reflex breathing pattern irregularities Tetraparesis respiratory arrest
Treatment of brain herniation
Dexamethasone
Mannitol
Clinical signs of Cranial trauma
transient loss of consciousness residual confusion ataxia changes in mental attitude contralateral hemiparesis Intracerebral hemorrhages stupor coma cranial nerve deficits
A decreasing level of consciousness suggests what area of the brain?
brainstem
cortical
Asymmetry in the menace response or limb proprioception without cranial nerve deficits indicates….
lesions in the contralateral cerebral hemisphere
Stuporous patients with multiple cranial nerve deficits and respiratory pattern irregularity have a lesion where?
brainstem
Extensor rigidity with all 4 limbs extended and opisthotonus and stupor/coma is suggestive of what?
involvement of both hemispheres
Decerebrate rigidity
What is suspected when pupillary light reflex is not normal?
increased intracranial pressure
Mydriasis suggests a lesion where?
progressive lesion in the brainstem
Unilateral mydriasis suggests…
unilateral cerebellar herniation or unilateral hemorrhage into the brain stem
What is the first signs to treat with cranial trauma?
Shock and other life threatening
What fluids are administered to patients with cranial trauma?
hypertonic saline
Hetastarch
What do Hypercapnia and Hypoxia cause?
cause vasodilation and increased intra-cranial pressure
What kind of prognosis do animals in a coma over 2 days have?
poor
What are the characteristics used to develop the coma scale?
Motor activity
Brain Stem Reflexes
Level of Consciousness
Narcolepsy
sudden recurring attacks of sleep
Clinical signs of Narcolepsy
cataplexy loss or reduction of muscle tone and signs of weakness head drop or collapse for seconds to minutes suddenly falling asleep
Diagnosis of Narcolepsy
EEG
What is the cause of Narcolepsy?
mutation in the orexin receptor gene
Treatment of Narcolepsy
Amphetamines
Antidepressants
Feline Ischemic Encephalopathy
Ischemic necrosis in the cerebrum caused by Cuterebra migrating through the cribiform plate inducing vasospasms of brain arteries
What causes Feline Ischemic Encephalopathy?
Cuterebra
Clinical signs of Feline Ischemic Encephalopathy?
Respiratory signs seizures abnormal behavior circling hemiparesis unilateral blindness anisocoria head tilt
Treatment of Feline Ischemic Encephalopthy
Ivermectin to kill the parasite with concurrent use of prednisone and antihistamines
Canine granulomatous meningioencephalomyelitis
Inflammatory condition in middle aged dogs that is associated with perivascular infiltration of mononuclear cells in the white matter of the brain and cervical spinal cord
Two forms of Canine granulomatous meningioencephalomyelitis
focal form
disseminated form
Clinical signs of the dissmeinated form of Canine granulomatous meningioencephalomyelitis
ataxia paresis/paralysis seizures behavioral changes circling vestibular signs facial or trigeminal nerve paralysis cervical pain
Treatment of Canine granulomatous meningioencephalomyelitis
cytosine arabinoside
cyclosporin
procarbazine
What form of FIP causes neurological signs
the dry form
Neurological Clinical signs of FIP
Nystagmus
Anterior uveitis
Chorioretinitis
What does Feline Leukemia virus cause?
degenerative myelopathy
What is the cause of bacterial meningitis?
S. Intermedius
How is bacterial meningitis spread?
Hematogenously
Clinical signs of bacterial meningitis
Cervical pain
rigidity
seizures
Steroid responsive meningitis-arteritis
arteritis in the meninges
Subarachnoid hemorrhage
Diagnosis of Steroid responsive meningitis-arteritis
peripheral neutrophilia and the CSF usually has increased protein and neutrophilic pleocytosis
Treatment of Steroid responsive meningitis-arteritis
Prednisone
Immunosuppressive drugs such as azathioprine in combination with steroids
What is the treatment of algal encephalitis?
NO TREATMENT! FATAL!
Dysautonomia
degeneration of neurons in sympathetic and parasympathetic ganglia and dysfunction of the autonomic nervous system
What is the cause of Dysautonomia?
Clostridium botulinum type C
Clinical signs of Dysautonomia in cats?
mydriasis prolapsed third eyelids reduced lacrimal secretions regurgitation constipation
Clinical signs of Dysautonomia in dogs?
dysuria dilated bladder mydriasis dry mucous membranes decreased tear production vomitation/regurgitation reduced anal reflex lethargy depression weight loss 3rd eyelid prolapse
Treatment of Dysautonomia
supportive therapy
What are the three types of deafness
Conductive
Central
Sensorineural
Conductive deafness
chronic otitis externa/media which prevent sound being transmitted to the inner ear
Central deafness
damage to central auditory pathways and is generally associated with brain stem signs
Sensorineural deafness
congenital or acquired abnormalities of the cochlear
In what breed does congenital deafness occur?
Dalmations
What is sensorineural deafness associated with?
pigment-associated with white, merle and piebald dogs at greater risk
What is recommended for bilaterally deaf puppies?
Recommended to destroy them and not breed them
What agents are ototoxic?
Aminoglycosides
ototoxic antibiotics
antiseptic solutions
ceruminolytic agents
Epilepsy
disease condition characterized by recurrent partial or generalized seizures
Primary or idiopathic epilepsy
seizures of unknown cause
Secondary or symptomatic epilespy
seizures because of discernible intra-cranial or extra-cranial disease
Seizure
begin in a ‘focus’ in the cerebral cortex where neurons suddenly fire in extremely rapid and frequent bursts. Restricted to the focus causing ‘partial’ or ‘focal’ seizures or it spreads to involve both cerebral cortices and cause ‘generalized seizures’
What causes partial or focal seizures?
post-traumatic lesions, space occupying lesions, cortical developmental disorders
Partial motor seizure
lesion in the motor cortex resulting in brief episodes of abnormal movement in the contralateral body part
Clinical signs of partial motor seizures
chewing gum fits
flexing to one side of the body
head turning
head bobbing
Clinical signs of Partial seizures causing abnormal behavior
excessive salivation licking chewing sudden voracious consumption of food or water vocalizing trembling
Clinical signs of partial sensory seizures
“fly-biting”
“tail chasing”
Types of Generalized seizures
Generalized tonic-clonic seizure tonic seizures clonic seizures atonic seizures absence seizures incomplete
What are the three phases of seizures
Pre-Ictal
Ictal
Post-Ictal
Clinical signs of the Pre-Ictal Phase
subtle behavioral changes
seeking out the owner
restlessness or anxiety
Clinical signs of the Ictal Phase
10-30 seconds of widespread sustained muscle contractions - the limbs are extended rigidly, opisthotonos with apnea and cyanosis
Ictal Phase
sudden loss of consciousness and simultaneously the animal falls to the ground
Clonic clinical signs
alternating contraction and relaxation of the body musculature Running paddling chewing gum jaw movements pupillary dilation salivation defecation urination
Post-Ictal Phase
marked by gradual return to consciousness with varying degrees of depression, fatigue, fright, daze appearance, aimless pacing, thirst, hunger
Clusters of seizures
serial seizures separated by minutes or hours
Status epilepticus
Continuous seizure lasts for longer than 5 mins or where there are serial seizures between which there is not a full return to consciousness
How do you differentiate between REM-behavior disorder and sleep seizures?
owners should attempt to wake the animal during an episode
How do you differentiate primary/idiopathic from secondary/symptomatic epilepsy?
Idiopathic epilepsy is treated with anticonvulsant drugs
Symptomatic epilepsy - the underlying disease must be treated
What is the most important cause of seizures?
toxicity
What kind of patients is idiopathic epilepsy seen in?
1-5 years old
What are some possible precipitating factors of seizures?
Hypoglycemia High protein meals head trauma visits to the vet lawnmower engines
What can be used to differentiate between generalized and partial seizures?
EEG
What is the decision to institute anticonvulsant therapy based on?
frequency and severity of seizures
When should an animal be started on anti-convulsant therapy?
seizures more frequently than once every 6-8 weeks
clusters of seizures
present in status epilepticus
What are the goals of anti-convulsant therapy?
reduce the frequency, duration, or severity of seizures without tolerable side effects
What receptors does Phenobarbital act on?
GABA receptors
What is a contraindication for phenobarbital?
Liver disease
What are the side effects of phenobarbital use?
Polyuria
Polyphagia
polydipsia
Mild to moderate increases in ALT and ALP
How does phenobarbital enhance its own metabolism?
inducing cytochrome P450 system
How does Bromide work?
by moving through the chloride channels and hyperpolarizing membranes
What is Bromide used for?
Add-on drug for epilepsy refractory to or poorly controlled with phenobarbital
What kind of diet is contraindicated with the use of Bromide?
High salt diet
What are the adverse effects of Bromide?
polyphagia polydipsia polyuria irritability attention seeking aimless pacing
What is a major contraindication with Bromide?
renal insufficency
What are some reasons for therapeutic failure?
Owner compliance Incorrect dosage due to weight gain Genetic factors Incorrect diagnosis New concurrent disease Hepatic enzyme induction
What are some therapeutic options besides phenobarbital?
surgery: separation of the corpus callosum Vagal nerve stimulation Acupuncture Ketogenic diets Hypoallergenic diets
Juvenile epilepsy
Generalized tonic-clonic seizures in normal puppies up to 4 months of age
What kind of epilepsy are seen in cats 1-5 years of age?
Idiopathic epilepsy
Feline audiogenic reflex seizures
seizures in response to high-pitched sounds such as crinkling of tin foil, metal spoon dropping, clinking or tapping
What is the drug of choice for seizures in cats?
Phenobarbital
What are the contraindications of Bromide in cats?
Feline asthma
renal insufficiency
What are the 5 important things to stabilize in a patient?
Airway Fluids to maintain BP Temperature Glucose ECG
What do you do if you cannot control the seizures with phenobarbital or diazepam?
Induce general anesthesia with pentobarbital
