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Chief Complaint


Organ System


Modified Fisher Grading Scale for Subarachnoid Hemorrhage (SAH)

States severity of SAH based on amount and type of blood on CT with associated vasospasm risk.

This scale only applies to aneurysmal subarachnoid hemorrhage (aSAH).

  • Thin SAH is classified as < 1mm in depth.
  • Thick SAH is classified as ≥ 1mm in depth.

Clinician must be able to identify subarachnoid hemorrhage (SAH) and major neuroanatomical landmarks on head CT.


  • Neurological and neurosurgical consultation should be obtained for patients with evidence of any SAH on imaging or lumbar puncture, whether the SAH is likely to be aneurysmal or non-aneurysmal in nature.
  • Computed tomographic angiography (CTA) of the head is helpful to determine the presence of a lesion suitable for surgical or endovascular intervention.
  • Consider discussing need for cerebrovascular imaging, such as CTA of the head or catheter angiography, with neurological or neurosurgical consultant before ordering.
  • Similarly, consider deferring the decision to start medications that have been shown to alter outcomes in aSAH (such as nimodipine and/or aminocaproic acid) to the neurological or neurosurgical consultant.
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