encephalopathy and seizures Flashcards
encephalopathy
- syndrome of brain dysfuction
- usually forebrain signs
- non-specific
primary CNS causes of encephalopathy
- neoplasia
- epilepsy
- inflammatory/infectious
- increased ICP
- trauma
- hemorrhage
- vascular
- degenerative
metabolic causes of encephalopathy
- hepatic
- hypertensive
- toxic
- renal/uremic
diagnostics for hepatic encephalopathy
- CBC, serum chem panel, UA
- fasted pre- and post-prandial bile acids, ammonia
- AUS, portal/rectal scintigraphy
hepatic encephalopathy treatment
- low-protein diet
- ion-trapping (lactulose PO or enema)
- antibiotics (metronidazole, neomycin)
congenital vs acquired hydrocephalus
- congenital
- malformation of ventricular system
- can sometimes prevent deterioration
- cannot reverse damage
- acquired
- secondary
- neoplasia, obstruction, reduced drainage
- choroid plexus tumors
- FIP
- potential to return to normal with treatment
- secondary
hydrocephalus treatment
- reduce CSF production
- prednisone
- omeprazole
- furosemide, acetazolamide
- crisis: mannitol, hypertonic saline
- establish drainage
- ventriculoperitoneal shunt
seizures
- forebrain: cerebrum and diencephalon
- etiology
- primary CNS disturbance
- neurologic manifestation of systemic disease
classification of seizures
- generalized (grand mal, tonic-clonic)
- partial (focal motor seizures, Jacksonian march)
- psychomotor (fly biting, running fits, rage)
generalized seizures “petit mal”
- mild generalized seizures
- brief loss of muscle tone
- may remain sternal or ambulatory, but ataxic
- episodic weakness, disorientation
- +/- drooling, vomiting, urination, defecation
partial seizures
- head turning, tonus of one limb, altered behavior, licking, fly biting…
- seizure focus
- localized to one area of the cortex
- does not spread across entire cerebrum, can generalize at any time
psychomotor seizures
- complex partial seizures, behavioral seizures
- running fits, fly biting, episodic rage, hissing, drooling
- sensory and motor components
- may have autonomic manifestations
- often from the temporal lobe and limbic system
cluster seizures
- >2 seizures in 24 hours
- period of normalcy in between episodes
- reliable pattern of multiple seizures at each event
- does not matter if generalized or partial seizures
- usually require > 2 meds for adequate control
status epilepticus
- rapidly recurring seizures with incomplete recovery between episodes
- more likely in large breed dogs
- toxins
- metabolic
- sudden drug withdrawal; ineffective drugs
- progressive disease
ddx for possible seizures in dogs
- hypotensive episodes (HSA bleeds)
- cardiogenic events (PH, arrhythmias)
- respiratory (BUAS, collapsing trachea)
- hypertensive episodes (pheochromocytoma, PLN)
ddx for possible seizures in cats
- hypertensive episodes
- 3rd degree AV block
- behavioral
- movement disorder
cat seizures
- keep checking body temp
- idiopathic cats often require multiple drugs at the onset
signalment and history
- age: 1-5 yrs
- breed:
- small, terrier type vs large, dolichocephalic
- cat
- chronicity & progression
- acute onset vs long-standing
- seizures along vs other neuro deficits
- concurrent diseases
extracranial seizure differentials-metabolic
- BG
- PSS
- Ca
- increased PCV
extracranial seizure differentials-toxic
- EG
- strychnine
- metaldehyde
- Pb
- OPs
- tetanus
- Bufos
extracranial seizure ddx-vascular
- arrythmia
- ischemic and hemorrhagic events
extracranial seizure ddx-nutritional
- thiamine deficiency
concurrent disease to consider
- pulmonary hypertension
- PLN/PLE
- hepatic disease
- known neoplasia
PSS
- typically young dogs with global signs
- BUT
- wax and wane
- older dogs
- asymmetrical signs
- resting ammonia
- useful to know if the current episode is due to HE, so you need a sample when animal is abnormal
- when in doubt, run fasted pre- and post-prandial bile acids
shunt breed predisposition
- pug
- yorkie
- pom
vascular breed predisposition
- CKCS
- greyhound
- cats
thiamine deficiency
- cats fed coldwater fish-thiaminase
- non-traditional home-cooked diets
intracranial ddx-inflammatory
- GME
- NME
- NLE
- …
intracranial ddx-neoplasia
- primary
- meningioma, glioma
- secondary
- metastasis, nasal, pituitary
intracranial ddx-vascular
- ischemic vs hemorrhagic infarction
- thromboembolus
- hemorrhage
intracranial ddx-infectious
- crypto, rabies
- distemper
- toxo, FIP
intracranial ddx-anomalous
- hydrocephalus
- lissencephaly
intracranial ddx-traumatic
- acute (immediate)
- chronic (weeks to years)
intracranial ddx-degenerative
- storage disorders
stereotypes for idiopathy epilepsy
- lab
- germand shepherd
- australian shepherd
- poodle
stereotypes for inflammatory disease
- pug
- yorkie
- poodle
- maltese
- chihuahua
- pomeranian
- dachshund
- frenchie
- boston
stereotypes for primary neoplasia
- dolichocephalic breeds with meningioma
- brachycephalic breeds with glial tumors
- boxers with anything
ddx for dog <1 yr
- extracranial: PSS, BG, toxin
- intracranial: malformation, storage disease, infectious (distemper vs sepsis), IE
ddx for dog 1-5 yrs
- IE, inflammatory, infectious, neoplasia
ddx for dogs >5 yrs
- neoplasia, inflammatory, IE, vascular
ddx for cat
- infectious (crypto, toxoplasma, FIP, cuterebra)
- suspect idiopathic epilepsy
- neoplasia (meningioma, lymphoma)
- vascular
emergency management
- triage
- body temp
- hydration status
- BP mgmt
- BG, iCa, PCV/TS
- caution with bolusing fluids if structural IC disease or disrupted BBB
stopping the seizure
- diazepam
- PR or IN
- 20-30 min effect
- phenobarb
- loading dose
- keppra (levetiracetam)
- may need higher dose if on PB
- sodium bromide
indications for anticonvulsants
- absolute
- cluster seizures
- status epilepticus
- neuro deficits or suspicion of structural dz
- aggression pre- or post-ictal
mannitol or hypertonic saline
- high suspicion of structural dz and vasogenic edema
- they’re dying
- not going to help with active seizures
- mannitol can worsen hemorrhage
- hypertonic saline has been shown to be more effective than mannitol for herniation
corticosteroids
- known history of brain tumor or inflammatory disease
- they’re dying
- not going to help with active seizures
- will reduce vasogenic edema and decrease ICP
- don’t give if we don’t have a dx as it may hide nay inflam dz