What is status epilepticus?
Electrical Seziure activity at least 30 mins duration
What are cluster seizures?
Recurrent generalized epileptic seizure activity within 24 hours
What should you worry about in patients with status epilepticus?
7 yrs = Predisposing underlying brain dz
Which spp can have more rapid onset of cytotoxicity in status epilepticus?
Cats
What are the 2 main causes of neuronal death in status epilepticus?
Direct cytotoxicity of seizure (hypoxemia, ischemia, excitotoxicty)
Excitotoxicity - Excessive acitvation of glutamate receptors (excitatory) = Prolonged influx of Ca2+ into cell = Disruption of cellular metabolism
Which vitamin is a cofactor for cerebral aerobic glycolytic metabolism?
Thiamine
Why is bromide not recommended in cats?
High prevalence of adverse respiratory problems
What is the name of keppra and what is the MOA?
Levetiracetam - Binds to SV2A = synaptic vesicle protein
What is the MOA of gabapentin?
Structural analog to GABA
Inhibits voltage-gates Ca2+ channels in brain
What has been shown with gabapentin and seizures?
Mixed results = No benefit or slight benefit in reducing seizures
What is pregabalin?
Gabapentin analog - Increased affinity to subunit of voltage-gates Ca2+ channel
What is felbamate’s MOA?
Dicarbamate drug = Blocking NMDA-mediated neuronal excitation; potentiation of GABA mediated neurnal Na+ and Ca2+ channels; may be protective against hypoxic and ischemic neuronal damage
Name 2 possible adverse events with felbamate.
Potential hepatotoxicity (esp with pheno) May increased pheno levels, may cause KCS
Why is felbamate not used in cats?
Hepatotoxicity and blood dyscrasias (dcoumented in humans and dogs)
Which antionvulsant appears to have no appreciable hepatic metabolism?
Keppra (levetiracetam)
What is the MOA Of zonisamide?
Blockage of T-type Ca2+ and V-gated Na+ channels in brain
Faciliates dopaminergeric and serotonergic neurotransmission in CNS
Scavenging of free radicals
Enhancing action of GABA in brain
Inhibitiion of glutamate-mediated neronal excitation in brain
Inhibition of carbonic anhydrase activity
What potential adverse event has occurred with zonisamide?
Hepatotoxicity (rare) - metabolized by hepatic microsomal enzymes
Name viral causes of meningoencephalomyelitides.
Canine Distemper FIP Rabies CHV WNC Parvovirus Post-vaccine (rabies)
Name 3 dog breeds that get necrotizing mengingoencephalomyelitis?
Pugs
Maltese
Yorkies
What should you consider when you have a dog with multifocal neurologic signs?
Multifocal disease
What should you consider if involuntary, rhythmic jerking?
Distemper (also see extranural signs = foot pad and nose hyperkeratosis, rapid cachexia)
What should you consider if cervical rigidity/neck pain, acute fever, enutrophilia, massive pleocytosis?
Steroid0responsive meningitis arteritis (SRMA)
What should you consider in a pug with focal or generalized seizures?
Pug ME
What should you consider in a yorkie with brainstem signs = abnomral mentation, CN deficits, gait abnormalities?
Yorkie ME
What should you consider if you have a puppy 2-6 months old, acute onset, skull enlargement , forebrain signs (behavior change, blindness)?
Hydrocephalus with periventricular encephalitis
In with ME is fever most likley?
Bacterial infections and SRMA
What should be considered if your CSF reveals lymphoplasmacytic pleocytosis?
Vrial infections, chronic phase of SRMA, GME, and breed specific necrotizing encephalitis
What should be considered if your CSF reveals neutrophilic pleocytosis?
Bacterial infections and acute phase of SRMA
What should be considered if your CSF reveals mixed cell population?
Protozoal dz, FIP, chronic bacterial infection, necrotic lesions of GME
What should be considered if your CSF reveals eosinophils?
Rare eosinophilic encephalitis of unknown origin, protozoal, parasitic, mycotic infections, occasonally in GME and FIP
What is the classic finding on MRI of ME?
Hyperintense lesions in T2-weighted image (multifocal), contrast enhancing (not specific, other lesions can look this way too)
What can be seen if bacterial ME is suspected?
CSF often helpful (neutrophilic pleocytosis), clinical course rapid!, extranural lesions (sinusitis, otitis media)
What can be seen if viral encephalitis?
Mononuclear pleocytosis - Do antigen detection (PCR or IHC)
What is the ideal treatment for Toxoplasmosis and Neosporosis?
If muscle involvement = clindamycin
If CNS = TMS
Need at last 4-8 wks of treatment
What is the prognosis and treatment options for mycotic encephalitis?
POOR prognosis; long tx (9 months)
Cryptococcosis (cats and dogs) - Amphotericin B and fluconazole
What are the 2 most common events that result in cererovascular disease?
- Ischemia/infaraction
2. Hemorrhage
What is a cerebrovascular accident?
Stroke = Sudden onset of nonprogressive focla brain signs secondary to cerebrovascular disease
What is the penumbra in an ischemic stroke?
Tissue that has potential for recovery = target of interventional tx
Name possible underlyign diseases that can be seen in patients with ischemic stroke.
About 50% of cases dx based on MRI had other underlygin diseases
30% systemic hypertension = secondary to CKD or HAC
Name 2 dog breeds that are over-represented in ischemic strokes.
CKCS and Greyhounds
What percentage of ischemic strokes are cryptogenic?
about 50% - No underlyign cause = Brain infarct of unknown origin
What is a hemorrhagic stroke?
Blood leaks from vessel directly into brain = hematoma in parenchyma or subarachnoid space = mass causes physical disruption and pressur eon brain = Increased ICP and decreased CSF
How common is primary hemorrhagic stroke in dogs?
Rare in dogs
Name several secondary causes of hemorrhagic stroke in dogs.
Congenital vascular anomaly, brain tumors, inflamamtory dz of vessels, IV LSA, brain infarction, impaired coagulation
What is the classic presentation for an animal with cerebrovascular accident?
Usually abrupt onset of neurologic signs followed by arrest and then regression of deficits
What is the Monroe Kellie Doctrine?
Change in volume of one intracranial component (tissue, blood, etc) balanced by compensatory change in another = Exhaustion of this can result in herination
How is hyperventilation helpful in hemorrhagic stroke?
yperventilation is used to decreased ICP by causing hypocapneic vasconstriction (Need to monitor PCO2 closely, bc if excessively = decreased CBF)
What is the prognosis for cerebovacular events?
Variable - many revolve in weeks with only supportive care
No evidence that region of brain affects or type of infarction affects prognosis
Worse prognosis in dogs that had systemic disease, more likley to have recurrent infarcts/events
Name several primary intracranial tumors.
Meningiomas Glial tumors Neuroepithelial tumors Nasal tumors Pituiatry gland tumors Pinela gland tumors Germ cell tumors
What are 3 secondary effects of brain tumors?
- Peritumoral edema
- Hemorrhage
- Intracranial hypertension
In which brain tumor did surgical removal (cats and dogs) show longer survival than irradiation alone?
Menigiomas - Excision can be curative
In which spp are menigiomas hard to excise?
Dogs (more invasive, need radiation and chemo
In cats - complete excision is possible
What is known to affect prognosis in menigiomas?
Histologic subtyping affects prognosis - Meningothelial better than fibroblastic, anaplasti, and psammomatous)
What is a glioma?
Invasive tumor located deep and very vascular
What is a potential treatment for hydrocephalus?
Ventriculoperitoneal shunt
When is radiation the treatment of choice for brain tumors?
Brainstem tumors
What potential side effects can occur with the brain and radiation?
Late responding tissue to radiation, thus may not see acute injury but instead SE within weeks to months = Demyelination
Name 3 chemotherapy options that can penetrate the BBB?
Lomustine (highly lipophilic to cross BBB) - used to treat glioma and meningioma
Hydroxyura - No evidence in dogs for meningioma
Cytosine arabinoside - Intrathecal for CNS lymphoma
How can you treat peritumoral edema in the brain?
Anti-inflammatory dose of steroids
What is an AA subluxation?
Instability and subluxation of C2 (axis) relative to C1 (atlas) = Cervical pain and/or myelopathy in toy and miniature breeds (rarely in large breeds and cats)
What are the 3 main ligments that hold the axis in position?
Apical and alar ligaments
Transverse atlantal ligament
Dorsal AA membrane
What is the most common abnormality associated with AA-subluxation?
Dens abnormality (agensis or hypoplasia, dorsal angulation, fracture/avulsion, changes in ligaments)
What dog breeds get AA-subluxations?
Chihuahua, Yorkies, toy poodles, Poms, Japanese chins, Maltese
What is the classic localization of AA- subluxation?
C1-C5 myelopathy - cervical pain to tetraparesis
What is the treatment of choice in animals with neuro signs and AA-subluxation?
Surgery = Ventral fixation of AA joint (79-92% success, no specific technique favored)
Which breeds are affected by canine cervical spondylomyelopathy?
Great Dane and Dobermans
What is another common name of canine cervical spondylomyelopathy?
Wobbler Syndrome
What are the 2 types of compressive lesions in canine cervical spondylomyelopathy?
- Osseus compression (bony stenosis) - Young, immature dogs (static or dynamic)
- Soft tissue compression - Dorsal, lateral, ventral
What type of compression in Wobbler’s is more common in young dogs?
Soft tissue compression (dorsal)
What type of compression in Wobbler’s is more common in older adult dogs (esp Dobermans)?
Ventral soft tiss ue compression
When is surgical therapy preferred in Wobbler’s disease?
In patients with severe neurologic signs, patients that fail medical tx, or progressive dz
What surgical technique is best for Wobbler’s disease?
lesions
What is the post-op recurrence rate in Wobbler’s disease?
10-40% - Progression of initial lesions vs “domino
What is degenerative lumbosacral stenosis?
Degenerative condition of LS joint (L7-S1) causing pain and radiculopathy
What CS are common regardless of if an animal has peripheral vs central vestibular?
Head tilt, nystagmus, and ataxia
In vestibular disease, the head tilt is _______ the lesion.
Toward unless lesion in caudal cerebellar peduncle - then AWAY from lesion (also see ipsilateral hemiparesis)
With nystagmus the slow phase is______ the lesion.
Toward the lesion
If a patient has bilateral vestibular disease what is lost?
Normal oculovestibular reflex is lost
When an animal with vesitbular disease is falling or rolling they prefer to lie on which side?
They prefer to lie on the side of the lesion
If circuling is present in a vestibular disease, it is _____ the lesion.
Toward the lesion
Positional vertical nystagmus and limb paraesis are most consistent with which type of vesibular disease?
Central vestibular disease
If there is CN deficits more than CN VII, what type of vestibular disease should be considered?
Central vestibular disease
What is the signalment of dog and cat with idipathic vestibular disease?
Dog = Older
Cat = Young to middle age
Dramatically improve in 1-2 wks, recurrence is possible
Name 3 dog breeds and 2 cat breed with congential peripheral vestibular disease. What can it be associated with?
GSD, Doberman, English Cocker
Siamese and Burmese
Associated with lymphocytic labyrinthritis
Which antibiotic can lead to peripheral vestibular disease and deafness?
Aminoglycosides
What deficiency (Esp in cats) can have vestibular ataxia as an early sign?
Thiamine
What is Chiari-like malformation and syringmyelia?
CM - Mismatch of cadual fossa (skull) and volume of contents (cerbellum and brainstem)
Neurally structures are pushed caudally into oramen magnum obstructin flow of CSF = Syringomyelia
What is another name for Chiari malformation?
COMS - Caudal occipital malformation syndrome
What is the most common breed with Chiari malformation?
CKCS!!! 95% thought of CM; 50% though to have CM and syringomyelia
What percentage of dogs will have CS of syringomyelia?
About 35% - CS within 1-4 yrs
What can be predictive of CS for syringomyelia in CKCS?
BAER anormalities
Name 3 drugs that can be used to reduce CSF production.
Furosemide, cimetidine, omeprazole
What is the most common neuromuscular disorder in dogs?
Myasthenia gravis
What type of medications are used to treat Myasthenia gravis in dogs?
Cholinesterase inhibitors = Pyridostigmine and neostigmine
What type of chest mass can be related to myasthenia gravis?
Thymoma
In a patient that has acute fulminating myasthesia gravis what should be considered?
In people they are treated with Ig therapy and plasma exchange!!
What is masticatory muscle myositis?
Most common in dogs - acute forms muscle swelling and trismus are noted (severe form linked to CKCS), in chronic stage marked atrophy is noted. Very steroid responsive in acute phase and moderately so in the chronic stage
Which breed can get a severe form of masticatory muscle myositis?
CKCS
How is masticatory muscle myositis diagnosed?
2M Antibody titer and muscle bx to assess for severity (fibrosis)
What is the treatment of masticatory muscle myositis?
Immunosuppressive steroids with taper over 4-6 months
When a boxer presents with stilited gait, muscle atrophy, and regurgitation, what should you consider?
Polymyositis - In boxer screen for neoplasia
What is extraocular muscle myositis?
mmune mediated inflammatory myositis limited to extraocular muscles.
What is dermatomyositis?
familial, immune mediated, inflammatory disease of striated muscle, skin and microvasculature of young Collies, Shetlands and Collie-mixes. Usually occurs in the first six months of life. Treatment includes immunosuppression with corticosteroids, treatment of secondary infections, Vitamin E.
Name several inflammatory myopathies secondary to infectious disease?
Neospora caninum (clindamycin + TMS) Toxoplasmosis gondi (cats, CNS, resp, GI, cysts in muscle bx, IgG and IgM titers, clindamycin) Hepatozoan americanum Lesihmania infantum Trypanosoma cruzi Viral: FeLV and FIV
What should you consider in a patient with rigid pelvic limb hyperextension, msucle atrophy, and concurrent polyradiculoneuritis?
Neospora caninum (clindamycin + TMS)
Name several non-inflammatory myopathies?
Hypothyroid myopathy
Hyperthyroid myopathy
Cushing’s myopathy (atrophy of type 2 fibers)
Steroid Myopathy
Which medication can result in acquire myasthensia gravis in cats?
Methimazole
What two antibiotics can result in peripheral neuropathies with chronic use?
Metronidazole and nitrofurantoin
What disease affects middle age to older large breed dogs that can result in progressive para or tetraparesis +/- laryngeal paralysis?
Chronic axonal degeneration = Idiopathic
If pain is elicited on flexion of shoulder, what should be considered?
Superaspinatus tendonopathy
What dogs are more commonly affected with supraspinatus tendinosis?
Mid to large breed dogs with active lifestyles
Diagnosis based on MRI
Where do steroids inhibit the arachidonic acid casacade?
Tissue injury = Phospholipids = Arachidonic acid = COX1/COX2 (prostaglandins, trhomboxanes, prostacyclin) or Lipoxygenase (LOX - Leukotriene formation) = Inflammation
Blocks as phospholipase inhibitors
What is aspirin?
COX1 and COX2 inhibitor
What can block LOX?
Ketoprofen and tepoxalin
How does hypokalemia affect the cell membrane in regards to electrical activity?
Hyperpolarization of membrane - Making cell insensitive to electrical stimulation
What is the most important reason for hypokalemia in cats?
Renal loss
What are the classical CS of hypokalemia?
generalized muscle weakness and ventroflexion of the neck; tremoring, fatigue and attack.
Which cat breed can have episodic signs of hypokalemia?
Burmese cats
What pre-op tx is recommended for Conn’s syndrome?
Spironolactone and amlodipine (hypokalemia and hypertension)
In what breed can hypokalemia be considered idipathic?
Burmese cats