Nontraumatic subarachnoid hemorrhage, unspecified

This code represents bleeding into the subarachnoid space, the area between the brain and the surrounding membranes, when the cause is not due to trauma. It signifies a spontaneous hemorrhage, often resulting from a ruptured aneurysm or arteriovenous malformation, without further specification of the etiology.

Use this code when documentation confirms a subarachnoid hemorrhage of nontraumatic origin, but the specific cause (e.g., ruptured aneurysm, AVM) is not identified or is pending investigation. It is appropriate for initial presentation or when the definitive etiology remains unknown after diagnostic workup.

• Avoid using this code if the specific cause of the nontraumatic subarachnoid hemorrhage is documented (e.g., ruptured cerebral aneurysm).
• Always review documentation for laterality and specific vessel involvement if available, as more specific codes may apply.
• Sequence this code as the principal diagnosis when it is the primary reason for the encounter, unless another condition clearly supersedes it.