Neuro 2 Flashcards
What is normal ICP in an adult in supine position?
7-15 mmHg
Calculation for cerebral perfusion pressure?
CPP = MAP - ICP
What is Cushing’s triad and what does it indicate / when is it seen?
Bradycardia
Widened pulse pressure
Irregular breathing
Late stage raised ICP
First stage of Cushing reflex, hypertension and tachycardia to overcome raised ICP and allow for brain perfusion but only as long as the ICP is not too high to overcome.
Second stage = bradycardia, ? due to increased BP triggering baroreceptors in the aortic arch, triggering parasympathetic activation
See notion for more
5 causes of raised ICP:
Traumatic head injury
SOL e.g. tumour
Hydrocephalus
IIH
Infection e.g. meningitis
5 signs / symptoms of raised ICP:
Headache worse on lying down
Papilloedema
Confusion, altered mental status, reduced conscious
Nausea and vomiting
Cushing’s triad
3 general management strategies in raised ICP:
IV mannitol
Raise head to 30 degrees
Controlled hyperventilation to try reduce pCO2
Management of IIH:
Weight loss
Topiramate - helps with weight loss and is also carbonic anhydrase inhibitor.
Acetazolamide
Management of hydrocephalus:
LP can be used for diagnosis in some cases and also bring relief.
EVD in right lateral ventricle
VP shunt
2 types of hydrocephalus:
Obstructive
Non-obstructive
Cause of obstructive hydrocephalus:
Structural prevention of drainage of CSF - dilation of ventricular system superior to the blockage.
E.g. tumour, acute haemorrhage or congenital anomalies.
Cause of non-obstructive hydrocephlus:
Imbalance of production and resorption of CSF.
Increased production VERY RARE choroid plexus tumour.
Reduced resorption at arachnoid granulations e.g. post haemorrhagic e.g. SAH, meningitis.
Risk factors (4) for IIH
Female
Obesity
Pregnancy
Drug causes; retinoids, steroids, OCP, tetracyclines, lithium
Most common cause of neuropathy?
DIABETES
Polyneuropathy vs mononeuritis multiplex?
Polyneuropathies are symmetrical and progressive at same time, compared to single nerves being picked off sequentially.
Causes of length-dependent polyneuropathy:
Diabetes
B12 deficiency
Alcohol
Immune e.g. paraproteins
Drugs; amiodarone, cisplatin and isoniazid
HIV
Paraneoplastic
Which infection classically triggers GBS?
Campylobacter
Reflexes in GBS:
Reduced / absent
What would be seen on an LP in GBS?
Increased protein
Normal wcc
Everything else normal
?Pathophysiology of GBS:
Molecular mimicry: B cells produce antibodies to infective antigens but these are molecularly similar to peripheral nerve e.g. myelin sheath.
What could be seen on nerve conduction studies in GBS?
Decreased motor conduction velocity due to e.g. demyelination
Peripheral neuropathies can be split into causes that predominantly present with motor OR sensory symptoms. Give some MOTOR causes:
MOTOR peripheral neuropathy:
GBS
Charcot Marie Tooth (CMT), HSMN
Lead poisoning
CIDP
Diptheria
Porphyria
Peripheral neuropathies can be split into causes that predominantly present with motor OR sensory symptoms. Give some SENSORY causes:
Diabetes
Alcohol
B12 deficiency
Uraemia
Leprosy
Which tracts are involved in SCDSC, and give corresponding symptoms.
Dorsal column - proprioception and vibration loss.
Lateral corticospinal - muscle weakness, hyperreflexia, spasticity, UMN signs in legs over arms.
Spinocerebellar - sensory ataxia, positive Romberg’s sign.
Classic triad of symptoms for normal pressure hydrocephalus, and ?cause:
Dementia
Incontinence
Gait disturbance
Large ventricles but normal ICP.
Most common congenital cause of hydrocephalus;
Aqueductal stenosis: blockage of drainage from third to fourth ventricle.
Most common form of MS:
Relapsing-remitting
