It is normal for patients with subarachnoid hemorrhage to develop a fever, but this must be assessed in conjunction with the patient’s body temperature and overall condition.

Sometimes, the amount of bleeding in the subarachnoid space is small and may cause mild fever, mainly due to the irritation of the nerves by bloody cerebrospinal fluid. In other cases, when there is a lot of bleeding, it may cause high fever, possibly central fever, which requires specific measures to reduce the body temperature, such as pharmacotherapy, applying ice packs, or using hypothermia therapy devices.

Additionally, some patients develop a fever three to five days after the subarachnoid hemorrhage, which might indicate a secondary infection, such as lung or urinary tract infections, necessitating anti-infection treatment.