What vascular neurological event causes fever?

Subarachnoid Hemorrhage Causes Fever in Vascular Neurological Events

Subarachnoid hemorrhage (SAH) is the vascular neurological event most strongly associated with fever development. 1

Relationship Between Fever and Vascular Neurological Events

• Fever following acute ischemic stroke is associated with poor neurological outcomes, increased risk of morbidity and mortality, possibly due to increased metabolic demands, enhanced neurotransmitter release, and increased free radical production 1
• The source of fever in stroke patients should be thoroughly investigated, as it may be secondary to the cause of stroke (such as infective endocarditis) or may represent a complication like pneumonia 1
• Fever is a common finding in subarachnoid hemorrhage and is associated with worse outcomes 1

Mechanisms of Fever in Subarachnoid Hemorrhage

• Blood in the subarachnoid space triggers an inflammatory response that can lead to fever development 1
• The presence of blood products in the cerebrospinal fluid can directly stimulate temperature regulation centers in the hypothalamus 1
• Vasospasm following SAH can cause ischemia in temperature-regulating centers of the brain 1

Other Vascular Neurological Events Associated with Fever

• CNS vasculitis can present with fever, particularly when it has an infectious etiology 2, 3
• Primary CNS vasculitis typically presents with headache, followed by encephalopathy and behavioral changes, with fever occurring in some cases 2
• Cerebral vasculitis secondary to infections (viral, bacterial, parasitic, and fungal) may present with fever as part of the inflammatory response 4, 5

Diagnostic Approach for Fever in Vascular Neurological Events

• When fever occurs after a vascular neurological event, the source should be identified through appropriate investigations 1
• MRI is the preferred imaging modality for evaluating suspected CNS vasculitis with fever, with abnormal findings in >90% of cases 2, 6
• Multiple infarcts of variable ages identified on MRI occur in up to 50% of patients with CNS vasculitis 2
• For suspected infectious causes of cerebral vasculitis with fever, specific antibody testing in blood and CSF, CSF culture and microscopy may be necessary 4

Management of Fever in Vascular Neurological Events

• Although treating fever after stroke makes intuitive sense, there are limited data demonstrating that the use of medications to lower body temperature improves neurological outcomes 1
• Small clinical trials have tested antipyretic medications (aspirin, ibuprofen, acetaminophen) in lowering body temperature after stroke, with modest success in achieving normothermia 1
• For CNS vasculitis with fever, a combination of steroids and pulse cyclophosphamide is generally recommended for induction treatment 7
• In cases of infectious cerebral vasculitis with fever, targeted antimicrobial therapy is essential 4, 5

Pitfalls and Caveats

• Fever in the setting of stroke may be misattributed to the vascular event itself when it could indicate an underlying infection requiring specific treatment 1
• Not all individuals with cerebral vasculitis have clinical or laboratory signs of inflammation, making diagnosis challenging 2
• Cerebral angiography has low specificity for vasculitis given significant overlap of findings with other cerebrovascular diseases 2
• Delaying treatment in cases of infectious causes of cerebral vasculitis can lead to poor outcomes 8

Remember that fever following a vascular neurological event should always prompt a thorough search for its cause, as appropriate management depends on accurate identification of the underlying etiology.