Subacute Onset Headache

CLINICAL DIAGNOSTIC MANUAL

Cause	Main Characteristics	Symptoms and Signs	Diagnostic Confirmation Tests
Elevated Intracranial Pressure	Throbbing headache, worsened by supine position.	Nausea, vomiting, blurred vision, papilledema (optic disc swelling).	Computed tomography (CT) or magnetic resonance imaging (MRI) of the head.
Encephalitis	Fever, altered mental status, behavioural changes.	Neck stiffness, seizures, neurological deficits.	Cerebrospinal fluid (CSF) analysis, electroencephalogram (EEG), brain MRI.
Temporal Arteritis	Headache in the temples, jaw pain while chewing, vision loss.	Jaw claudication, vision loss, fatigue, fever.	Temporal artery biopsy, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP).