What's the Diagnosis? By Lesley Walinchus-Foster
A 50 yo M presents to the ED w/ sudden onset severe headache. Symptom onset was 20 hours ago while hunting. His neuro exam in non-focal. CT head without contrast is done. What's the diagnosis? (scroll down for answer)
Answer: Subarachnoid Hemorrhage
- 75% caused by ruptured cerebral aneurysm
- Sensitivty of noncontrast CT for diagnosis of SAH is highest shortly after symptom onset and is estimated to be 98% within 6 hours- decreases to 91-93% at 24 hours
- CT followed by CTA can exclude SAH with 99% posttest probability
- Consider LP if clinical suspicion high and above imaging negative
- Patients can decompensate quickly due to respiratory depression, hypercapnia- intubate early if lethargic, altered MS, focal neuro deficit
- Remember pain management and sedation post intubation to prevent increased ICP
- General recommendation is SBP < 160 using titratable IV antihypertensive (labetolol, nicardipine)
- Start nimodipine even if patients normotensive- 60mg PO or via NG
- Seizure prophylaxis remains controverisal, discuss w/ NSG
References:
Hackman JL, Nelson AM, Ma O. Spontaneous Subarachnoid and Intracerebral Hemorrhage. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e New York, NY: McGraw-Hill; 2016.
McCormack RF, Hutson A. Can computed tomograph angiography of the brain replace lumbar puncture in the evaluation of acute-onset headache after a negative noncontrast cranial computed tomography scan? Academic Emergency Medicine. 2010 April 17. (4) : 444-451.