Which of the following is not a known complication of subarachnoid hemorrhage in the immediate several weeks following the initial bleed?

Hypernatremia is not typically considered a known complication of subarachnoid hemorrhage in the immediate weeks following the initial event. The immediate complications that are more commonly associated with subarachnoid hemorrhage include seizures, cerebral artery vasospasm, and rebleeding.

Seizures can occur due to the irritation of the cerebral cortex caused by blood in the subarachnoid space. Cerebral artery vasospasm is a significant concern because the presence of blood in the subarachnoid space can lead to narrowing of the cerebral arteries, potentially resulting in ischemia and delayed neurological deficits. Rebleeding is another major risk, especially in the first few weeks after the initial bleed, as integrity of the vascular structures may be compromised.

Hypernatremia, on the other hand, while it can occur in various clinical scenarios, is not specifically categorized as a complication of subarachnoid hemorrhage within the first several weeks. It may be seen in patients for other reasons, including dehydration or excessive sodium intake, but it does not correlate directly with the immediate management and complications of subarachnoid hemorrhage itself. This distinction highlights the focused nature of complications directly attributable to the hemorrhagic event and its acute sequelae.