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  • Subarachnoid Hemorrhage
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(warning) Immediate neurosurgery consult. In general, SAH patients should be admitted to neurosurgery. (warning)

Causes

  • Trauma
  • Aneurysm (saccular)
  • AVM
  • ICH with extravasation
  • Venous occlusion


Diagnosis

  • CT scan is 90-95% sensitive within 24 hours, and decreases to ~ 80% at 72 hours.
  • If CT is negative, but history is concerning, do an LP.
    • LP results (rule of ½):
      • RBCs appear at ½ hour
      • Xanthochromia appears at ½ day
      • RBCs disappear at ½ week
      • Xanthochromia disappears at ½ month
    • Xanthochromia
      • To check for xanthochromia:
        1. Find the centrifuge in the soiled holding room off dialysis on 7A
        2. Put some CSF into one tube (and mark it so it can be distinguished from the counterbalancing tube of water)
        3. Spin the CSF and the counterbalancing tube of water in the centrifuge
        4. Hold the two tubesup against a white piece of paper:
          • If you can tell the difference, the darker one is xanthochromic CSF.
          • If they look the same, there's no xanthochromia.
      • Alternatively, you can hand carry the CSF to the lab and make sure the lab uses the method above. Some people make check for xanthochromia by holding a single tube of CSF up to a light. It's not sensitive, and you don't need a lab to do that.
  • If the CT or LP is positive, urgent 4-vessel cerebral angiogram to look for aneurysm, possible clipping or coiling.
  • MRA usually detects aneurysm of 4mm or greater size.


Complications

  • Rebleeding ¿ usually within first 24 hours.
  • Hydrocephalus.
  • Seizures.
  • Vasospasm ¿ usually delayed about 5 days, but highest risk ~ day 4-11.
  • Hyponatremia from SIADH or cerebral salt wasting. Note that cerebral salt wasting looks just like SIADH based on serum and urine lytes, so be sure you know how to tell the difference as the treatment is vastly different.
    • For cerebral salt wasting:
      • check urine osms (normal is 285)
      • 0.9% NS has osm of 308, 1.8% with 616, 3% with >900
      • If urine osms >308, then NS is not enough, consider 1.8% or 3%
      • Do not run 3% through a peripheral line
  • Other systemic complications:
    • Pulmonary edema
    • Arrhythmia


Treatment

  • Bed rest with HOB ¿30 degrees
  • Triple H therapy may be considered for vasospasm¿ use 0.9% Normal Saline
    • Hypervolemia
    • Hemodilution
    • Hypertension
  • Blood pressure management ¿ keep MAP around 120.
  • Nimodipine 60mg po q4h for 21 days to reduce the risk of vasospasm.
  • Pain management

Guidelines

  • Most recent AHA guidelines for SAH are here .  



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