Flashcards in OHCM - Subarachnoid Hemorrhage Deck (35):
SAH - Typical age:
SAH - Etiology:
1. Rupture of saccular aneurysms (80%).
2. AV malformations (AVM; 15%).
SAH - No cause is found in ...?
SAH - Risk factors:
4. Bleeding disorders.
5. Mycotic aneurysms (SBE).
6. Perhaps post-menopausal decreased ESTROGEN (Female:Male=3:2 if >45yr).
SAH - Close relatives have ...?
3-5-fold increased risk of SAH.
Berry aneurysms - Common locations:
1. Junction of the posterior communicating with the IC.
2. Junction of the anterior communicating with the anterior cerebral artery.
3. Bifurcation of the MCA.
Berry aneurysms - ...% are multiple.
Berry aneurysms - Associations:
1. Sudden (usually, but NOT ALWAYS, within seconds), devastating typically occipital headache.
5. Coma often follow.
Coma/drowsiness may last for ...?
1. Neck stiffness.
2. Kernig (takes 6h to develop).
3. Retinal, subhyaloid and vitreous bleeds (=Terson's syndrome).
4. Focal neurology at presentation may suggest site of aneurysm (eg pupil changes indicating a CN III palsy with a Pcom artery aneurysm) or intracerebral hematoma.
5. Later deficits may suggest complications.
Retinal + Subhyaloid + Vitreous bleeds = Carries worse prognosis: mortality increases x5).
1. In primary care, only 25% of those with severe, sudden "thunderclap" headache have SAH.
2. In 50-60%, no cause is found.
3. The remainder have:
c. Intracerebral bleeds.
d. Cortical vein thrombosis.
SAH - Sentinel headache:
SAH patients may earlier have experienced a sentinel headache, perhaps due to a small warning leak from the offending aneurysm (6%), but recall-bias clouds the picture.
--> As surgery is more successful in the least symptomatic, be suspicious of any SUDDEN headache especially with neck or back pain.
Tests - CT:
Detects >90% of SAH within the 1st 48h.
Tests - LP:
LP if CT is -ve --> No contraindication >12h after headache onset.
Tests - CSF:
Uniformly bloody early on --> Becomes xanthocromic after several hours due to Hb breakdown products (bilirubin).
Finding xanthocromia confirms SAH?
Yes - Because it shows that the LP was not a "bloody tap" (don't rely on finding fewer CSF RBCs in each successive bottle).
Refer all proven SAH to ...?
Management - Re-examine:
1. CNS often.
2. Chart BP.
3. Pupils and GCS.
4. Repeat CT if deteriorating.
Management - Maintain ...?
Cerebral perfusion by keeping well-hydrated, and aim for SBP>160mmHg.
Treat increased BP only if very severe.
Management - Nimodipine:
60mg/4h PO for 3weeks, or 1mg/h IVI.
--> CCB that reduces vasospasm and consequent morbidity from cerebral ischemia.
Endovascular coiling is preferred to ...?
Surgical clipping where possible (7% increase in independent survival over 7yrs follow-up, but incr. risk of rebleeding).
Endovascular coiling - Do what before?
Catheter or CT angio to identify single vs multiple aneurysms BEFORE intervening.
Intracranial stents and balloon remodelling ...?
Enable treating wide-necked aneurysms.
1. Rebleeding (MCC of death).
2. Cerebral ischemia.
MCC of death - Occurs in 20% often in the 1st few days.
Due to vasospasm may cause a permanent CNS deficit --> MCC of MORBIDITY.
--> If this happens, surgery is NOT helpful at the time but may be so later.
Due to blockage of arachnoid granulations, requires a ventricular or lumbar drain.
COMMON - Should NOT be managed with fluid restriction.
Mortality in SAH - Grade I-V:
I - No signs --> 0%.
II - Neck stiffness and CN palsies --> 11%.
III - Drowsiness --> 37%.
IV - Drowsy with hemiplegia --> 71%.
V - Prolonged coma --> 100%.
Almost all the mortality occurs in the ...?
1st month - Of those who survive the 1st month, 90% surviva a year or more.
Data from the 2003 International Study of Unruptured Intracranial Aneurysms (ISUIA) show that ...?
RR of rupture for an aneurysm:
7-12mm across is 3.3 compared with aneurysms 12mm the RR is 17.
Patients with previous SAH have increased risk ...?
For new aneurysm formation and enlargement of untreated aneurysms.
--> Screening these patients might be beneficial, eg if multiple aneurysms, HTN, or a history of smoking.