Neuro Flashcards
Name the 6 main types of peripheral nerve damage
Demyelination (eg Guillan-Barre syndrome)
Axonal degeneration (eg toxic neuropathies)
Wallerian degeneration (both axon and myelin sheath degenerates)
Compression (entrapment neuropathies, eg carpal tunnel)
Infarction (microinfarction of vasa nervorum occurs in diabetes and arteritis)
Infiltration (infiltration of peripheral nerves by inflammatory cells - leprosy, granulomas, mets)
Name common risk factors for stroke /TIA
Hypertension, smoking, DM, heart disease, PVD, post-TIA, carotid artery occlusion, excess alcohol, clotting disorders, hyperlipidaemia
How does nerve regeneration occur?
Limited
Remyelination and axonal growth (~1mm/day)
Pathology of epilepsy?
Patients’ “seizure threshold” is lowered, meaning that the level of excitability at which cells will discharge uncontrollably is lower.
Neurons are HYPEREXCITABLE
Common things that push neuron excitability past the seizure threshold in epilepsy?
Sleep deprivation, alcohol, drugs, physical exhaustion, flickering lights, infection/metabolic disturbance,
Etc
Most common causes of peripheral neuropathy?
Diabetes Alcoholism Vitamin deficiency (B12) Infected / inherited (guillan-barre, Charcot-Marie-tooth) Drugs - eg isoniazid
What happens in a simple partial seizure?
Patient remains conscious
Focal motor seizure - jerking usually begins at corner of mouth/in one hand and sometimes spreads to involve entire side.
What happens in a complex partial seizure?
TEMPORAL LOBE SEIZURE
Impaired consciousness
Deja vu, jamais vu, vertigo, visual/auditory hallucinations, lip smacking/other motor disturbances, tachycardia, emotional disturbance, automatism (patient literally goes on autopilot and can wander off somewhere)
Drowsiness and confusion after attack
Difference between absence seizure and temporal lobe/complex partial seizure?
Absence = quicker recovery after the attack
Absence generally lasts 30s
What is status epilepticus?
A seizure that lasts >30 minutes
OR
Multiple seizures in between which consciousness is not recovered, lasting >30 minutes
MEDICAL EMERGENCY
How is status epilepticus treated?
Benzodiazepines (IV or IM)
2nd line - phenobarbital
3rd line - phenytoin
(+RRAPID)
Mechanism of carbamazepine? (Anti-epileptic)
Inhibits sodium channels
➡️reducing action potential propagation of neurons
Phenytoin has the same mechanism!
Mechanism of sodium valproate?
Increases GABA concentration
Inhibits sodium channels
Inhibits glutamate decarboxylase
First line for absence & generalised seizures, second line for partial
Triad of symptoms for meningitis?
Headache
Neck stiffness
Fever
Pretechial/non blanching rash - medical emergency!! Beware of septicaemic shock
Other symptoms/signs for meningitis, besides the triad?
(Triad = headache, stiff neck, fever)
Pretechial/non blanching rash - medical emergency!! Beware of septicaemic shock
Photophobia
Vomiting
Malaise, rigors
Positive Kernigs sign
Conscious but delirious in high fever
Focal signs may be present eg papilloedema, Diplopia.
Viral may be less prominent signs
