Brain Conditions Flashcards
A dog presents with a history of circling and falling over to the left side. On exam you see that the dog has nystagmus, with the slow phase toward the left. You also note miosis and enopthalmus of the left eye. No paresis or CP deficits are detected. What are the differentials for these signs?
(Peripheral Vestibular Dz)
DDx: Otitis media/interna
Canine idiopathic vestibular disease
Congenital (GSD, Beagle, Doberman, Siamese/Burmese @ 3m)
Although vestibular disease resolves with time, and there is no treatment, what medications can be used to alleviate vertigo and nausea?
Antihistamines
A dog presents to your clinic for sudden onset of circling and tilting his head to the right. You note hemiparesis on the right side, and the dog seems depressed. Vertical nystagmus is present and can be ilicited by head movement. Is this a peripheral or central problem?
Central Vestibular Dx
*Rotary/horizontal/vertical nystagmus. Hemi or tetraparesis. Eyes can move in different directions.
What are the MAIN causes of central vestibular disease?
Neoplasia
Encephalitis (distemper, FIP)
Infection with parvo virus in utero causes what pathology in cats and dogs?
Cerebellar hypoplasia
A 4 year old Maltese presents for tremors of the head and limbs that seem to come on when he gets excited, but never happen while he’s sleeping. What treatment is appropriate for this dog?
Prednisone @ 2mg/kg
*Inflammation in the cerebellum causes shaking/shivering in small breeds
A 10 month old Scottish Terrier presents with a history of getting stiff and falling over into a ball when someone comes to the front door. What medication is most appropriate for this patient?
Prozac
*Serotonin deficiency causing collapse with exercise or excitement. Prozac is a serotonin reuptake inhibitor. Non-progressive condition.
You are seeing a 6 month old Cavalier King Charles Spaniel who has been stiffening up after playing in the yard. The dog remains conscious, so the owner doesn’t think he’s having seizures. What medication might help this dog?
Clonazepam
*Hypertonicity syndrome that usually resolves over a couple years
What are teh 2 mechanisms that lead to hydrocephalus?
Decreased flow of CSF
Increased production of CSF
An 8 week old Chihuahua presents to your clinic with a history of incoordination and apparent blindness. You note a large, dome shaped head and strabismus. What is causing signs in this patient?
Hydrocephalus
*Congenital in toy breeds. Just inherently dumb puppies/dogs. Progressive. Can lead to seizures, blindness, deafness, tetraparesis.
*Can be aquired from FIP or toxoplasma
The owner of the Chihuahua would like to treat the hydrocephalus. What are the treatment options.
Shunts!
Dexamethasone can be used for temporary relief
A dog presents for seizures, confusion, and hemiparesis on the left side. The owners say it’s like he doesn’t even know them anymore. While examining the dog, you notice that he is walking slightly toward the left. You suggest a CT of the brain and find a mass in the cortex. What side is the mass on?
Right side.
*Cortical masses show contralateral locomotor signs
A dog presents with a recent history of left side paresis. Intellectually the dog seems normal, however, there are some cranial nerve deficits. You order a CT and find a mass in the brainstem. What side is the mass on?
Left
*Brain stem lesions will cause ipsilateral locomotor problems
While German Shepherds, Boxers, Miniature Schnauzers, and Golden Retrievers are predisposed to meningiomas, brachycephalics are predisposed to ______.
Gliomas
T/F: Cats diagnosed with malignant meningiomas have a better prognosis than dogs with the same tumor.
TRUE
*MST for cats is 1-3 years. MST in dogs is 4-6 months.
You have just diagnosed a glioma in a Boston Terrier. What treatment is not indicated for these tumors?
Surgery. Since these are not superficial tumors, resection would destroy too much of the brain.
*MST for gliomas is 4-12m
After removing a meningioma in a canine patient, you suggest radiation therapy. How much survival time does radiation offer, in addition to the year provided by surgery?
1-3 years
In patients with intracranial space occupying lesions, why are CSF taps and volatile gas anesthetics contraindicated?
Risk of brain herniation.
Intracranial pressure is already high. Volatile gas anesthetics and CSF taps increase ICP further, increasing the likelihood of herniation.
You begin a CSF tap on a dog with neurological signs such as strabismus, weak jaw tone, and lack of pupillary response. The dog suddenly goes into respiratory arrest. Based on the clinical signs and procedure, what treatment is indicated to hopefully alleviate the underlying cause, if the dog survives?
Dexamethasone
*This dog was showing signs of increased ICP, and the CSF tap likely induced a brain herniation, sending the dog into respiratory arrest. Dexamethasone reduces brain edema and may reverse the herniation.
CT on a cat with a history of trauma. The patient lost consciousness and has been exhibiting ataxia and CP deficits since the incident. On the scan you see areas of focal hemorrhage and edema. What is the diagnosis?
Contusion
You arrive in the treatment room to find a dog recumbant and unconscious, with its fore and hind legs extended and stiff. The dog’s head and neck are extended dorsally. What part of the cerebral cortex do you suspect is affected?
The whole thing is destroyed. (Decerebrate rigidity)
Dog A is depressed and has left sided hemiparesis. Lack of menace response and no reaction to nostril stimulation on the left side are noted, but the rest of the cranial nerve tests are normal.
Dog B is stuprous and has multiple cranial nerve deficits. He also has periods of tachypnea followed by apnea.
Where is the lesion in each of these dogs?
Dog A: lesion in the cortex (right side)
Dog B: lesion in the brainstem. (More pronounced stupor and multiple cranial nerve deficits. Cheyne-Strokes respiration indicates decreased PaCo2 responsiveness in the diencephalon.)
What IV fluids will you administer to a patient with a head injury and increased ICP?
Hetastarch (colloid)
*Will increase cerebral perfusion while decreasing edema (osmotic drag). Edema can be caused by the trauma itself or by administration of crystalloids.
Stabilization of a patient with a serious head wound includes IV Mannitol to decrease cerebral edema and ICP (secondary damage resulting from trauma). What is an important adverse effect of mannitol use?
Acture renal failure
Which inhalant anesthetic is indicated during the surgical treatment of a patient with a skull fracture and brain contusion?
Isoflurane
*Doesn’t increase ICP. Induce with short-acting barbiturates or propofol.
The coma scale gives the patient a number score based on 3 categories: Motor Activity, Brain Stem Reflexes, and Level of Consciousness.
What scores are given to normal animals, animals with good prognoses, and animals with a survival rate of less than 50%?
NL: 18
Good: 15-18
Less than 50% survival rate: less than 8
A Doberman presents with a history of sudden collapse while eating. The dog will become excited for meal times, begin eating, then fall over and sleep for up to 20 minutes before waking and continuing to eat. What gene is affected in this patient?
Mutation in the Orexin receptor gene
*Orexin prevents REM sleep and keeps animals awake.
An EEG is performed on the Doberman who keeps falling asleep while eating. During an episode, the test shows brain activity characteristic of sleep, confirming narcolepsy. What is the treatment plan?
Amphetamines (Ritalin) and/or antidepressants
Migration of what parasite can cause ischemic encephalopathy in cats?
Cuterebra
*behavior changes, seizures, unilateral blindness, circling, hemiparesis, head tilt.
A 7 year old Miniature Poodle presents with progressive neurological signs. CSF samples show a pleocytosis and elevated protein. MRI is pictured. What treatment will you suggest to the owner?
Cytosine arabinoside
Cyclosporin
Procarbazine ($$$)
* GME: MST one year
The owners of the Miniature Poodle decide to go with Prednisone to treat the neurological signs, because it’s much cheaper than the drugs you recommended. The dog presents for necropsy 2 weeks later. What do you expect to find on histo of the brain?
Perivascular infiltration of mononuclear cells in the white matter of the brain,
*Canine granulomatous meningoencephalomyelitis
What is the most common cause of feline encephalitis?
FIP (dry form)
Psychoseizures in cats are associated with what neurological disease?
Feline polioencephalomyelitis
(staggering disease)
Bacterial Meningitis and Steroid Responsive Meningitis-Arteritis can appear the same clinically. How can they be differentiated and how are the treatments different?
SRMA will have high IgA levels. If you see high IgA, treat with immunosuppressive doses of prednisone.
If not, treat with antibiotics (meningitis).
You are presented with a cat who hasn’t been eating for the past 2 days. On exam, you note that there is mucus buildup in the eyes. Bilateral mydriasis is noted and the nictitans is prominent. Heart rate is 100bpm and the cat is leaking urine onto the table. What infectious agent has been implicated in presentations such as this?
C. botulinum type C
*70% mortality in cats, 90% mortality in dogs
Congenital sensorineural (cochlear) deafness is most common in what breed of dog?
Dalmation
What type of epilepsy can be resolved by treating an underlying disease?
Secondary (symptomatic)
Secondary epilepsy is generally characterized by what kind of seizures?
Partial
Seizures in dogs younger than one year are typically attributed to what etiologies?
Toxic
Infectious
Congenital
Seizures in dogs older than 5 years are typically attributed to what etiologies?
Idiopathic (35%)
Neoplasia
Metabolic diseases
What is the most frequently observed seizure in veterinary medicine?
Generalized tonic-clonic
Abnormal findings during a neurological exam on a patient with a history of seizures suggests what type of epilepsy?
Secondary (symptomatic)
*Abnormalities indicate an underlying pathology
A Golden Retriever is prescribed phenobarbital after having one seizure a month for the past 3 months. You ask the owner to come back in 6 weeks to recheck labs. Results show increased ALT and ALP. Is switching medications indicated in this patient?
No. Phenobarb is an enzyme inducer, so ALT and ALP will be high. If bile acids and bilirubin are high, the medication is causing adverse liver effects.
HOWEVER, enzyme induction can decrease the concentration of PB in the blood, so it’s important to monitor PB levels to make sure they stay around 100-130 umol/L.
What type of seizures are most common in cats?
50% tonic-clonic
50% non convulsive
What is the DOC for epilepsy in cats?
Phenobarbital
(But Levitiracetam works better according to his notes?)
Bromides are contraindicated with what concurrent disease?
Renal insufficiency
Which drug is useful for refractory seizures, is a partial GABA agonist, is safe with few side effects, and requires no blood mointoring?
Imepitoin
Which drug is useful for pulse therapy, when given during the pre-ictal period at 3x normal dose?
Levetiracetam
You have a canine patient on phenobarbital, but his seizures are still not controlled. Which drug is most commonly added to the regimen first?
K-Bromide
A feline patient is not controlled well on phenobarbital alone. What drug can you add to the treatment regimen?
Levetiracetam
A dog presents to your clinic seizuring. You would like to give Diazepam but the seizure is too intense to administer it IV. What other routes of administration can you use?
Intranasal
Rectal
A dog is seizuring in your clinic but does not have an IV catheter in place. What drugs can you give IM to stop the seizure?
Midazolam
Lorazepam
A 10kg dog presents in status epilepticus and you give 5mg diazepam IV to stop the seizuring. You are about to administer an IV bolus of Phenobarbital as a loading dose. How much does this patient need?
200mg
*Phenobarb IV loading dose 15-20mg/kg
A 3 month old puppy presents for generalized tonic-clonic seizures. The patient is otherwise healthy and lab results are normal. What is your treatment plan?
Phenobarbital 5mg/kg (higher dose)
Wean if seizure free after 6 months
The phenobarbital dosage for cats is (higher/lower) than for dogs.
Lower
Do we expect to see liver enzyme induction in cats on phenobarbital?
NO
