Neuro 2 Flashcards
Where is CSF produced? How much/day
From arterial blood in the choroid plexus of the lateral and 4th ventricles
Diffusion, pinocytosis and active transport
600ml/day
How much CSF do we have?
140ml
Where does the CSF go?
Absorbed by the arachnoid villi/granulations into the venous system
7 functions of CSF
Buoyancy Intracranial volume adjustment Miconutrient and protein transfer Buffer resevoir Immune via cervical lymphatics Neurotransmitter transfer Drug delivery
Normal CSF characteristics
Clear
60% glucose of plasma
opening pressure 80-180mmH2O
Protein <= 500mg/dl
Name the most common reason for communicating hydrocephalus
Subarachnoid haemorrhage
Due to blockage of arachnoid villi with blood
When does idiopathic intracranial hypertension usually occur?
Overweight young females with headache and visual loss
Or after taking vit A, tetracyclines or withdrawal of steroids
Treatment: repeated LPs, CAi (acetazolamide), shunt surgery
What is the meaning of elevated rbcs found in the csf?
Traumatic tap or subarachnoid haemorrhage
Xanthachoromia (if bilirubin present then subarachnoid)
!!This is reliant on waiting 12 hrs after the headache began!!
Indications for LP
- Infections of the Central nervous System: Meningitis or Encephalitis secondary to other pathogens
- Subarachnoid Haemorrhage (SAH).
- Inflammatory/Demyelinating CNS diseases: MS
- Inflammatory Neuropathies: Guillain-Barré Syndrome,
- Idiopathic Intracranial Hypertension.
- Unexplained Pyrexia with neurological symptoms (particularly in children).
- Infiltration of the meninges: Leukaemia, Met. Melanoma.
What is dangerous about LP in meningitis?
Brain imaging is indicated before LP in patients with who have symptoms (e.g. reduced level of
consciousness) or signs (e.g. optic disc swelling), suggestive of significantly raised ICP, or focal neurology
Due to raised ICP->coning
When are LPs contraindicated?
Raised ICP Soft tissue infection of lumbar spine area Coagulopathy (high INR/low platelets) Focal neurological signs Hx of seizures in last week
How does the brain compensate for increased intracranial pressure?
Reducing CSF volume
Reducing blood volume (venous then arterial)
Reducing brain extracellular fluid
Why might intracranial pressure increase?
Expanding mass (haematoma, tumour, abscess) Increased CSF (hydrocephalus), blood (outflow obstruction) or brain (oedema)
How is cerebral vascular resistance altered?
Autoregulation (arterial contraction)
Chemoregulation (pCO2)
What is wrong with trying to blow off CO2 to reduce ICP?
Means that cerebral blood flow will reduce-> hypoxia
Signs of increased ICP
N+V (mornings, when lying flat, coughing or stooping)
Papilloedema
Reduced GCS
Cushing’s response (increase BP, decrease HR, late response)
Treatment of raised ICP
Head up Sedation (reduce metabolic activity of brain) Mannitol CSF ventricular drainage Decompression craniectomy
Features of migraine
Typically benign and recurring syndrome with female predominance
Onset in teens
Throbbing
Unilateral (60%)
N&V, photophobia and phonophobia
Associated visual, sensory, motor or speech disturbance
Name some triggers of migraine
Alcohol, chocolate, cheese, menses, hunger, missing a meal, lack of sleep, stress, period after stress,
anxiety, worry, depression, OC pills, HRT, perfumes, glare, flashes of light, physical exertion, head trauma
What is the classical visual aura in migraine?
Scintillating scotoma (zig zags)
Treatment of migraine
Acute attack: Triptans
Prophylaxis: Beta blockers, tricyclic antidepressants, antiepileptics
Treatments of cluster headaches
Treatment: - O2 inhalation 8L/minute, Triptans, Prednisolone
Prophylaxis: - Verapamil, Lithium, Prednisolone, Sodium valproate
Treatment of tension headaches
NSAIDs and TCAs (amitriptyline)
What GCS is treated as coma?
8 or less
This is the threshold for intubation