Feline Neuro Flashcards
Postural reactions in cat (3)
hopping, wheelbarrowing, extensor postural thrust
How to test cutaneous trunci in cat?
fluff hair up & gently pull a single strand
Which cranial nerve test is unreliable in the cat?
Menace due to their whiskers (CN 2&7)
- (can come from behind but 20% still don’t respond even if healthy)
Feline Hyperesthesia Syndrome
1. Clinical signs
2. Age of onset
3. Tx
- Tail-swishing, head-shaking, “hallucinations” (lick/bite at base of tail)
- ~1 years old
- Gabapentin (2/3 respond); clomipramine
Feline Hyperesthesia Syndrome - possible pathophysiology
Vacuolar myopathy or seizure
Feline Idiopathic Epilepsy
1. Characteristics
2. Age of onset
3. Side effects of phenobarb vs keppra
- Rapid running around, normal interictal states, seizure during “resting” conditions
- Onset < 7y/o
- Phenobarb: sedation, polyphagia, ataxia, elevated ALP (concern)
Keppra: sedation, anorexia, hypersalivation from drug formula
Why should KBr NEVER be used in cats?
Risk of developing life-threatening pneumonitis
Why should Diazepam NEVER be used in cats?
Causes hepatic failure (accumulation of bile acids in hepatocytes- cats cannot break them down properly)
Audiogenic Reflex Seizures
1. Stimulus
2. Common signalment
3. Tx
- Consistently triggered by high-pitched sounds (crinkling of foil, plastic bag, tapping of glass)
- 15 y/o Birmans (10-19 y/o)
- Tx = eliminiating/avoiding the noise works in 75% of cases; keppra
Hippocampal Necrosis (Feline Temporal Lobe Epilepsy)
1. How is it dx
2. Signalment/Clinical Signs
3. Tx
- MRI T2 Flair - hippocampus
- Young cat with focal-generalized seizures ; hyper-salivation, lip-smacking, aggressive episodes, vocalization
- Phenobarb; refractory to conventional ASDs
A cat has a hx of uncontrollable diabetes mellitus. What is a possible cause unique to cats?
A tumor of the anterior pituitary gland that is secreting excessive growth hormone (Feline Acromegaly)
Why can 1º neuro disease manifest as ophthalmic disease?
The optic nerve is not a true nerve. It is an extension of brain tissue.
Feline Infectious Peritonitis - Neuro form (dry)
1. Pathophysiology of CNS Dz
2. Dx
3. Tx
- Viremia causes severe vasculitis (brain is highly vascularized) -> dementia, seizures, cerebellar-vestibular signs
- Pathognomic dx = MRI showing lateral ventricular dilation (pus-filled) + periventricular hyperintensity
- Tx = antiviral adenosine nucleoside analogue; invariably fatal w/out tx
pyogranulomatous perivascular inflammation
Toxoplasmosis
1. Pathophysiology of CNS Dz
2. What two ways can it manifest as CNS dz
3. Tx
- Reactivation of latent infection in immunocompromised cat: the latent bradyzoites reactivate into tachyzoites, which then rapidly multiply in CNS tissue
- Brain (encephalitis, granulomatous inflammation) or Spinal Cord (segmental myelitis)
- Clindamycin for ≥1 or ≤6 months
Cryptococcus
1. Pathophysiology of CNS Dz
2. Clinical signs
3. Dx
4. Tx
- Inhalation of spores from environment -> nasal (URI) cryptococcosis extends into CNS via cribiform plate
- Roman nose, seizures, gait abnormalities, abnormal cranial nerve exam; severe = obtunded
- Fungal culture (narrow-based budding); serology, CSF
- Fluconazole + amphotericin B + flucystosine
How does Feline Leukemia Virus (FeLV) affect the CNS?
Meningomyelitis (progressive ataxia, paraparesis -> paralysis)
How does Feline Immunodeficiency Virus (FIV) affect the CNS?
Meningoencephalitis or encephalitis w/ seizures + behavioral changes –> perivascular lymphocytic cuffing on histo
How does Feline Panleukopenia (FPV) manifest as CNS Dz?
Trans-placental transmission - cerebellar hypoplasia (uncoordinated movements, hypermetria/goose-stepping, head tremors, intention tremors). Predisposition to lymphoma.
https://www.vet.cornell.edu/departments/cornell-feline-health-center/health-information/feline-health-topics/lymphoma
True or False: a cat with cerebellar hypoplasia 2º to FPV has a guarded prognosis and therefore should be euthanized.
FALSE - it is a non-progressive disorder and they can live a good quality of life as long as they are kept in a safe environment.
- indoor, non-slip flooring, large/easy-access litter boxes, raise food/water bowls)
Feline Ischemic Encephalopathy:
1. Presentation
2. Cause
3. Time of year
- Acute blindness
- Cuterebra larvae
- August > July/Sept (cuterebra migration season)
Cuterebra larvae; Cuterebra is a large fly, which lays eggs in the ground at the opening of rodent burrows; the eggs hatch and the larvae attach to the hair and skin of a host (such as a rabbit); they enter the nose and penetrate the moist lining, from which they migrate and eventually reach a location under the skin, where they continue to develop; the cat may become a host as it hunts or moves in the area where the larvae are located—in most cases, the larvae migrate to locations under the skin (especially around the head) of the cat, but if they follow an abnormal migration pattern in the cat’s body, they may end up in the brain
Global Cerebral Ischemia
1. Pathophysiology
2. Clinical signs
3. Prognosis
- Maxillary artery becomes occluded during dentals when spring-loaded mouth gag is used -> cerebral hypoxia -> ischemia
- Upon recovering from anesthsia: acute blindness, obtunded, seizures
- Guarded to poor (does not respond well to tx)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5661754/
While in some species (dogs, humans) the main cerebral blood supply arises from both the internal carotid and basilar arteries, cats rely solely on the maxillary branch of the external carotid artery (MB-ECA) to feed the cerebral vascular circle.2–5 This branch lies in immediate proximity to the caudal aspect of the jaw, and is compressed between the bony tympanic bulla and angular process of the mandible when the mouth is opened to maximal extent 3,4,6,7 In addition, the medial and lateral pterygoid muscles and temporalis muscle border the vasculature and exert pressure when the mouth is placed in full extension, compromising flow.1,2,3,7 Occlusion of the MB-ECA can cause cerebral hypoxia, resulting in global cerebral ischemia.1–7 Further compounding ischemia, the use of anesthesia may cause a reduction in perfusion to vital structures.1,2,3,4,6 Areas of the brain most vulnerable to ischemic damage are the cerebral cortex, hippocampus, caudal colliculi and thalamic nuclei.1
Cervical Ventral Flexion
1. Most common ddx
2. What anatomical feature of cats may also be a cause?
- Top ddx = Hypokalemia!! (poss. ddx = NH4Cl toxicity)
- Cats lack a dorsal nuchal ligament
Recall: HypoK+ = FASTER cell REpolarization
NH4Cl = ammonium chloride; can be found in disinfectants
Role of thiamine (B1) in body and what can predispose a cat to becoming deficient in it
Thiamine/VitB1 is essential for CHO metabolism. Consumption of raw fish (that contain thiaminase), cooked food in which thiamine has been destroyed, or meats preserved with sulfites (cleaves thiamine)
Clinical signs of thiamine deficiency
Vestibular signs, vision loss, mydriasis w/out PLRs, ataxia, seizures
Myasthenia Gravis
1. Pathophysiology
2. Clinical signs
3. Important r/ow prior to dx
4. Prognosis
- Autoantibodies block ACh receptor -> no cellular depolarization = no muscle contraction
- Severe weakness; decreased esophageal motility; decreased anal tone
- R/o craniomediastinal mass/thymoma!
- NO mass = good (adult onset), YES mass = guarded/poor
Thymoma associated with MG & cause paraneoplastic syndrome
Paraneoplastic syndrome = immune system reacts to the tumor (i.e., in MG, immune system responds by producing the autoantibodies that block ACh receptor)
What is the top primary brain tumor in cats?
Meningioma
Survival time of a cat dx w/ meningioma with and w/out SX:
With SX = 37 months MST
W/out SX = 18 days MST
What is the most common neoplasm affecting the spinal cord? How likely is it to be 1º CNS tumor?
Lymphoma. Rare to be 1º, most likely metastasized from elsewhere (esp. renal or bone marrow lymphoma)
Renal lymphoma, unfortunately, carries a poor prognosis. Average survival with this type of lymphoma is only 3-6 months, though there are isolated reports of cats surviving far longer. Renal lymphoma tends to spread to the brain and central nervous system; this occurs in approximately 40% of renal lymphoma cases and worsens the prognosis for this disease.
https://vcahospitals.com/know-your-pet/lymphoma-in-cats
