Neuro Flashcards
What defect do cats with complex partial seizures have?
ABs against voltage gated potassium channels (alter excitability neural membrane) - NG hippocampal necrosis
Dogs juvenile epilepsy mutation of voltage gated K channel
Threshold for voltage gated sodium channels?
- 55
Membrane usually - 70
Mechanism of phenobarbital and diazepam?
GABA receptor agonist - increase time chloride channel open when GABA binds, make cell more neg
Glutamate - what is it and what does it do?
Major excitatory neurotransmitter.
AMPA and NMDA receptors.
AMPA depolarises membrane, release Mg ion, block NMDA. Bind NMDA allow sodium conduction and increase excitatory effect. NMDA channel also allow calcium in - more prolonged synaptic effects.
Can cause cell death from too much calcium if too much NMDA agonism.
Coton de Tulear motor learning/cerebellar dysfunction?
mGluR1 mutation (GRM1) - which is conc on purkinje cells cerebellum
Segments for patellar reflex?
L4 - L7
How to manage different kinds of brain oedema?
Cytotoxic/interstitial - underlying cause
Vasogenic - steroid/osmotics
What lactate most likely to produce encephalopathy?
D-lactate, not usually measured - bacteria in GI tract?
L-2-hydroxyglutaric aciduria?
Staffie and Yorkie, around 4y, grey matter hyperintensity
Measure in urine.
L2HGDH mutation.
First signs of lysosomal storage disease?
Cerebellar
Brain tumour characteristics that predict seizures?
Frontal lobe, contract enhancement, subfalcine/subtentorial herniation.
When should brain neoplasia be considered as a differential for seizures?
> 4y
Prognostic indicators for brain tumours?
Pos - meningioma, esp cat, supratentorial, surgery + RT
Neg - glioma, metastatic infratentorial
Idiopathic epilepsy dogs/cats?
Cats only 22 % idiopathic vs majority dogs
Dog male > female
Idiopathic epilepsy in cats later onset cf familial
Idiopathic more likely dog if > 4w between first and second seizure
Genetic evidence IE?
Pure breed
Offspring (more chance and earlier age)
Genetic up to 33 % incidence
Lagoto Romagnolo - LGI2
Belgian shephard - ADAM23
Both voltage gated potassium channel
Tier dx idiopathic epilepsy?
I 2 + seizure > 24h apart 6m-6y no exam abnormalities no min bloods abnormalities
II plus BAST MRI and CSF
III EEG
When is MRI/CSF recommended?
After exclusion reactive seeizures Age < 6m > 6y Intracranial neuro abnormaltiies Status/cluster Drug resistance single AED highest dose
MRI changes idiopathic epilepsy?
Might have vasogenic/cytotoxic oedema with recent seizure, resolve 10 - 16w
Piriform, temporal, hippocampus, cerebral cortex
When to give AED?
Structural sTATUS 2 + IN 6m Bad interictal Increasing frequency or severity over 4 seizures (three interictal periods)
What AED to use first?
Phenobarbital > bromide
Phenobarbital similar efficacy imepitoin (latter less SEs)
30 % IE need > 1
50 % need SEs to be seizure free
Goal of tx IE?
Seizure freedom = extend inter seizure interval to 3 x pretx after min 3m tx.
Partial = prevent status/cluster, decrease frequency/severity
Negative px control IE?
Male, entire, young, cluster, border collie, GSD, Staffie
Euthanasia - young, high initial frequency, poor control, status
Criteria for CVA?
> 24h clin signs (otherwise is transient ischaemic attack)
Ischaemic (non-hemorrhagic > haemorrhagic ischaemic) more common than haemorrhagic
Territorial infarct = large vessel - cerebellum/cerebrum
Places - cerebellum, cerebrum, thalamus/midbrain, often ischaemic stroke does middle cerebral artery in dogs
Ischaemic stroke?
No cause found 50 %
Greyhounds more than all other breeds combined - hypertension? - non haemorrhagic ischaemic
Territorial cerebellar CKCS, rostral cerebellar artery
Lacunar thalamic/midbrain large breed
Hyperlip and mini schnauz?
Haemorrhagic ischamic - venous thrombosis/vascular damage with leakage during repercussion - eg HSA
Cats - feline ischaemic encephalopathy middle cerebral artery.
Global ischaemia?
Peracute neuro dysfunction after GA/CPR
Mouth gag cat - maxillary arteries - cerebral ischaemia vision hearing
Ketamine, brachycephalic
Prognosis with CVA?
Good if survive > 30 d.
Ischaemic stroke cause = neg
Intracranial haemorrhage (non traumatic) - 60 % good/excellent, cerebellum neg , hypertension neg
A vasorum good outcome
GME tx?
Procarbazine, cytarabine (both cross BBB)
Ciclosporin - might cross in GME? Trapped endothelial cells?
Female predip
NME/NLE?
NME cerebrum with meningeal, loss demarcation white/grey matter - pug/maltese - lymph
NLE cerebrum and brainstem with less meninges/cerebral cortex - yorkie - lymph/mono
Procarbazine not as effective
What AB cross BBB?
TMPS
Most common fungal meningoencephalitis?
Crypto (neoformans) both cats and dogs
Crypto more likely to be in CSF also
Antigens Crypto, coccidioides, blastomyces
NOT aspergillus/histoplasma
Culture hazardous to humans - blasto, coccidiosis, histo - these might be assoc with pulm lesions
What antifungals cross BBB?
Fluconazole, flucytosine (NB drug resistance latter)
NOT itraconazole
CSF FIP?
Neutrophilic then lymph/macro
Metronidazole tox?
Maybe GABA - treat with diazepam
Vestibular dog forebrain cat
SRMA CSF?
Increased IgA, B:T cell ratio (blood too), IL6 and IL 8
CD11a expression - neutrophils to subarachnoid space
MMP2
Serum and CSF IgA v sens less spec
Clinical presentation SRMA?
Can have deficits if chronic, may be due to subarachnoid bleeding
Half of IMPA BMD/Boxer/Akita have concurrent meningitis
SRMA remission?
80 %
IgA might still be increased
CRP predicts relapse
Discospondylitis bacteria?
Staph, strep, e coli
Aspergillus in young GSD female
Young basset systemic TB
Brucella
Discospondylitis sites?
L2-4 for migrating plant material (diaphragmatic crus insertion)
L7 - S1,. caudal cervical, mid-thoracic, thoracolumbar
May be assoc empyema
Discospondylitis presentation?
Spinal pain
30 % fever/systemically unwell
Blood/urine culture pos 75 %
Imaging discospondylitis?
XR may be N 1st 2-4w
XR - narrow disc space, irregular end plate, lysis/osseous proliferation
XR change lags behind clin imp
Discospondylitis neg px?
Fungal, fracture/subluxation, endocarditis
Hypothyroid neuropathy?
GAG/glycogen accum in Schwann cells causes dysfunction and demyelination.
Microtubule assembly and axonal transport req T4
NaKATPase dysfunction and impaired axonal transport
Mucinous deposits compress cranial nerves?
Neuro in hypothyroidism?
Single/several limbs
Trigeminal, facial, vestibular, often unilateral often multiple
Axonal degeneration/demyelination
Polyradiculoneuritis?
Racoon, vax, infection
Guilian Barre syndrome - shared antigen inciting stim with peripheral nerves
anti-GM2 ganglioside ABs
Ventral nerve roots inflamm
Ddx MG tick paral botulism
Steroids not helpful. IVIG might be
Tick paralysis?
Dermacentor/Ixodes
Neurotoxin female ticks prevents ACh release
5-9d post tick attachment
Cats resistant
AUS - cats too, plus ANS/cardiac dysfunction, get worse after tick removal
Botulism?
Neurotoxin type C (BoNTC), v rare cats
SNARE cleaved by toxin, no Ach release
Aminoglycoside and ampicillin potentiate NM blockade
Myaesthenia gravis pathophys?
AutoAB cf nicotinic AChR, complement mediated destruction
MG signalment?
<4 or >9
Akita, GSD, GRet
Abyssinian, Somali
Clinical presentation?
Mesaoesophagus less common in cats
Cervical ventroflexion more common cats
Spinal reflexes usually there generalised diminished fulminant. fulminant not better with rest.
Fulminant - around 15 % dog and cat, u retention poss, assoc with thymoma
Focal - ocular, facial, oesophagus, pharyngeal, laryngeal
Concurrent dz MG?
Thymoma, hT4, hAC, polymyositis, masticatory myositis
AChR AB titre?
Species specific.
98 % generalised.
May be neg early, affected by steroids.
Edrophonium test?
Inhibits anti cholinesterase
Isn’t perfectly specific and not all MG improve
Cholinergic crisis - weakness salivation tremors vomiting bradycardia bronchoconstriction resp distress
Atropine and intubation req
MG tx?
Pyridostigmine/neostigmine
Bradycardia hyper salivation diarrhoea vomiting muscle cramping weakness
Mycophenolate, ciclosporin, azathioprine spare innate target adaptive immune - MMF no diff survival
Spontaneous remission 88 %
Congenital MG?
JRT, springer, mini dachs - AChR deficiency
Other breeds probably the same, samoyed/smooth fox terrier
Auto recessive GDH JART SFT
6 - 9 W
Gammel Dansk Honsehund 4m and not responsive to anticholinesterase - presynaptic?
Need to quantify AChR in muscle bx
Spontaneous resolution mini dachs, GDH stable and mild
Labrador EIC?
DNM1 auto rec
Enzymes maintain synaptic vesicle function in sustained neurotransmission
< 2y
Los patellar reflex
Pyruvate/lactate normal
Feline panleukopenia?
FPV in last 3w gestation/1st 3w life, destruction germinal layer, cerebellar hypoplasia
Hydrancephaly
Vac mod live FPV in pregnancy
FIP?
33 % neuro, most common in non-effusive, cerebellum/pons/medulla oblongata
Eyes 53 %
Seizures 1/3 = poor px
37 % normal MRI
RTPCR in CSF, serology unhelpful
