Neurology Flashcards
Brain death examination -cranial nerves
pupil response to light: II III (optic oculomotor) corneal reflex: V VII (trigeminal facial) (reflex response to central pain- tests same nerves) vestibulo-ocular reflex: III, IV, VI, VIII (oculomotor, trochlear, abducens, vestibulocochlear) gag reflex: IX X (glossopharyngeal, vagus) cough X (vagus)
Causes of aseptic meningitis
no bacteria isolated on CSF: infective: viral; funga; mycobactertium non infective: lymphoma; leukemia; sarcoid; SLE; vasculitides; Medications (NSAIDS; bactrim)
Causes of seizures
structural lesions: infarct; hemmorhage; tumour; trauma non structural lesions: Drug OD (antipsychotic; antidepressants; opiods; isoniazid) EtOH use/withdrawal infection- systemic or CNS hypoxia electrolyte disturbances metabolic encephalopathies (hepatic, renal, glucose abnormality) anti epileptic dose decrease Idiopathic
Compare features of critical illness myopathy with critical illness neuropathy
Myopathy: proximal; sensation preserved; relfexes preserved until late; nil fasciculations; myocardial dysfunction possible; contractures present NCS: decreased CMAP; SNAP usually normal (risk factors: status asthmatics; steroid use; NMBD use; severe sepsis; MOF) Neuropathy: distal; sensation involved; reflexes decreased/absent; fasciculations present; no myocardial invovlement; no contractures NCS: decreased SNAP and CMAP (conduction velocities normal) (risk factors: Severe sepsis; MOF; prolonged stay)
DDx of weakness in ICU
cortical: stroke; mass occupying lesion; metabolic encephalopathy brainstem: stroke; hemmorhage; tumour spinal: ischemia; compression; hemmorage; tumour; MS; transverse myelitis peripheral neuropathy: GBS; critical illness myopathy; NMJ: Myasthenia gravis; botulism; delayed NMBD reversal; pesticide poisoning; muscle contraction: electrolyte disturbances (low K; high Mg; High Ca); critical illness myopathy
Define delerium
disturbance of consciousness, attention, cogniition and perception which develops over a short period of time and fluctuates during the course of the day
Define NCSE (non convuslive status epilepticus0
change in behaviour or mental processes associated with continuous eplieptiform EEG changes but without major motor signs
Grading of SAH
Clinical Grade 1: GCS 15 Grade 2: GCS 13-14 Grade 3: GCS 13-14 with motor involvement Grade 4: GCS 7-12 Grade 5: GCS 3-6
ICP wavekorm peaks
P1: percurssion avw from arterial pulsation P2: itidal wave represents intracranail compliance P3: dicrotic wave represents av closure
Indicatins for ICP monitor
Servere closed head injury: GCS 40yrs, SBP<90mmHg, motor posturing,
consider for hydocephalus, cerebral edema, stroke, hepatic encephalopathy
indications for surgery in SDH
evidence of neurological deterioration or midline shift>5mm or clot thickness> 10 mm
Management strategies of ICP>20
Tier1: head up 30 degrees; Analgesia; Sedation ; Drain EVD; Drain NG Tier 2: Osmoetherapy 3%NSaline- 3mLs/kg over 10 mins; Mannitol: 0.5-1g/kg over 30 mins Tier 3: Decompressive craniotomy; Mild hypothermia; Barbiturate coma;
NCS axonal versus demyelination injury
Axonal: decreased amplitude of CMAP; no temporal dispersion; no increased distal latency; no decreased conduction velocity; no conduction block; F waves latency normal; Demyelination: F wave latency prolonged (early sign); prolonged distal latency; Decreasd CMAP if conduciton block and temporal dispersion; decreased conduction velocity (typically a late feature); (not all features need to be present )
Nexus c spine rules
imaging required if any of: midline tenderness; distraction injury; altered GCs; intoxicated; focal neurologic deficit;
Preconditions for determining brain death clinically
normothermia
normotensive
intact neuromuscular function
exlcusion of effects of sedative drugs
absence of severe electrolyte deficiency
ability to examine brain stem function - one ear one eye
ability to perform apena testing- may be precluded by resp failure or c spine injury
