Neurology Flashcards
what is the max amount of CSF fluid you can remove for a sample?
1ml/kg
what is the site of sampling for CSF
cerebellomedullary cistern- easier more risk
lumbar cistern - more difficult less risk
contraindications for CSF sample?
increased ICP
coagulopathy
cerebellomedullary cistern contraindicated in some conditions eg cervical trauma
are the following evaluation of MRI or myelography in spinal diagnostics?
more soft tissue detail
more likely to be diagnostic
more expensive/ equipment
takes 1 hour
expertise necessary for interpretation
MRI
are the following evaluation of MRI or myelography in spinal diagnostics?
risk of seizure, neuro degen, dysrthmia, resp arrest, infection, death
cervical or lumbar punctures challenging
intra-axial lesions not shown
standard x-ray eqiupment only or CT
quicker
myelography
what spinal condition does AChR ab in blood indicate
acquired myasthenia gravis
what spinal condition does 2M Ab in blood indicate
masticatory myositis
what is the neostigmine response test used for?
test for junctionopathies eg myasthenia gravis
prolongs action of acetylcholine- see if improves condition
what are electrodiagnostics used for?
identify denervated muscles- extent and severity
what does electromyography test for
if spontaneous activity, is abnormal muscle nervation
what is motor neuron conduction velocity used to test
assess conduction along a nerve (minimum 2 sites)
what is F wave electrodiagnostics used for
assess nerve roots, help identify conditions such as polyradiculoneuritis
what is repetitive nerve stimulation used to test?
assess neuromuscular junction for myosethenia gravis
repeatedly stimulate nerve 3-5 times
what neurological condition is this?
Px: sympathetic denervation
Cx: miosis, ptosis of upper eyelid, protrusion 3rd eyelid, enophthalmus, conjunctival hyperaemia
Dx: +/- radiographs (neck, chest, bullae), MRI (brain, c-spine, brachial plexus),CSF
- 1% Phenylephrine topical administration to the cornea
o 1 st order – dilation in 60-90 minutes
o 2 nd order – dilation in 20-45minutes
o 3 rd order – dilation in
horners syndrome
seisures are due to dysfunction of what area of the brain
forebrain
paresis of all or ipsilateral limbs, decerebate rigidity, depression stumpour and coma, cranial nerve deficits and possible vestibular signs
indicate dysfunction of which area of the brain?
brainstem
intention tremors, abnormal menace with normal vision and PLR, delayed initial then hypermetric postural responses indicate lesion in which part of brain
indicate dysfunction of which area of the brain?
cerebellum
disorientation with contralateral blindness, normal gait and circling with decrease postural responses in contralateral limbs
indicate dysfunction of which area of the brain?
forebrain
how is intracranial pressure calculated? (ICP)
vestibular eye movements/ nystagmus good early indicator of increased ICP as swelling blocks front and back of brain so eyes dont follow head movement
clinical signs of increased ICP?
mental status changes: depression, stupor, coma bradycardia and hypertension altered PLR vestibular eye movements/ nystagmus abnormal postures
What brain condition is this:
fine tremor – rapid, low amplitude, worse with stress/excitement,
+/- other deficits: head tilt, reduced menace response, ataxia
Dx: CSF – very mildly inflammatory, +/- MRI to rule out other problems
how would you treat
idiopathyic tremor syndrome Tx: - corticosteroids for 4-6m - +/- other immunosuppressive drugs - diazepam initially
Pgx: fair to good prognosis but possibility of relapse
What brain condition is this
how would you treat
infection:
Cx: usually acute CNS signs (obtundation and CN deficits most common), neck pain , pyrexia
CSF: increased protein concentration and pleocytosis; phagocytosed organisms in CSF rare
CSF/blood culture (positive sometimes) inside abscess or in small amounts
bacterial meningitis
intoxication with
Organophosphates, pyrethrin and pyrethroids, lead, ivermectin, metaldehyde, tremorgenic mycotoxins, medications (antidepressants, amphetamines, metronidazole, etc)
often leads to which clinical signs?
brain condition
reactive seisures
acute (<24h) onset, often GI, cardiovascular or respiratory signs before or at same time
§muscle tremors and fasciculations often seen
how would you assess severity of head trauma in a patient?
modified glasgow coma scale (higher score= better prognosis)
this is a serial neurological assessment
how would you treat severe head trauma?
Fluid therapy: restore intravascular volume to ensure adequate CPP (resuscitation then maintenance)
Isotonic or hypertonic crystalloids, colloids and blood products
o Avoid glucose containing fluids: as hyperglycaemia is associated with a poorer outcome
o 7,5% saline: reverses shock, decreases ICP, increases CBF and oxygen delivery
Reduce raised ICP
o Mannitol: ↓ blood viscosity, ↑ CBF and oxygen delivery, free radical scavenger, osmotic effect follow with crystalloid therapy to prevent dehydration contraindicated in hypovolemia
o Hypertonic saline
hyperosmotic agent, free radical scavenger:
Contraindicated: hyponatraemia, cardiac or respiratory disease
how to calculate CPP (cerebral perfusion pressure)
CPP= MABP- ICP
can you give steroids in head trauma cases?
NEVER
asc with hyperglycaemia and lactic acid production (inc infection risk)
Hydrocephalus
abnormal dilation of ventricular system within cranium
Sx: toy breeds, young age
Cx: domed shaped head, persistent fontanelle, abnormal behaviour, cognitive dysfunction, obtundation, circling/pacing, seizures, vestibular sig
Hydranencephaly + Porencephaly
communicating with subarachnoid space and/or lateral ventricles
Cx: signs in 1st few months (circling, abnormal behaviour) or up to years few years (seizures)
Hepatic encephalopathy
any aetiology of acute or chronic liver failure - most commonly portosystemic shunt (PSS)
reversible neurological manifestations secondary.
Cx:
- Vague signs - failure to thrive; weight loss; PU/PD; GI sign
- Forebrain signs: behaviour changes; pacing; blindness; seizures
- Rare brainstem or cerebellar signs reported in older dogs
Dx: relies on bile acid stimulation test, fasting ammonia, ultrasound or CT angiography
Tx: normal hepatic treatment but also neurological seizure control WITHOUT HEPATIC METABOLISM
levetiracetam, KBr, PB, propofol
Hypoglycaemia
aet: insulinoma, liver disease, insulin overdose, juvenile hypoglycaemia
Cx:
- Lethargy, ravenous appetite and anxiety
- weakness and tremors
- Reduced vision and seizures
Dx: low glucose levels (typically less than 3 mmol/l) – check insulin at same time
BRAIN USES MORE GLUCOSE THAN ANY OTHER ORGAN
what element derangement would cause
altered mentation, blindness, seizures, coma and death
why be careful when correcting?
sodium
rapid replacement will cause swelling
Storage disease
brain condition- defect of a lysosomal hydrolase enzyme
early onset, diffuse neurological dysfunction, progressive course, leading to death
Px: accumulation and storage of substrate(s) within the cytoplasm of neurons, as well as in cells in other organs
changes in behaviour, memory, and learning ability: disturbances in sleeping, staring into space, getting stuck in corners, loss of housetraining ability, pacing, or vocalizing at night, newly developed behaviour problems
cause by: accumulation of beta-amyloid, with senile plaque formation and neurofibrillary tangles
what is this condition?
how treated?
Cognitive dysfunction= pathological deterioration of the brain
Tx: Selegiline, nutritional supplementation with antioxidants and other brain protective compounds and behaviour modification/environmental enrichment
cerebrovascular disease MUOs+ FIP metronidazole toxicity hypothyroidism and thiamine deficiency brain tumours
peripheral or central vestibular disease?
central
otitis media/ interna
idiopathic vestibular disease
facial nerve paralysis
central or peripheral vestibular disease?
peripheral vestibular disease
which breeds are predisposed to congenital deafness?
dog+ cat breeds with white pigmentation and blue eye colour
what are 2 hearing tests used in veterinary
BAER= brainstem auditory evoke response OAEs= otoacoustic emissions
