Headache

Red Flags

	Red Flag	Clinical Features	Etiologies to Exclude
S	Systemic signs, symptoms, or disease	fever, weight loss, HIV, immunosuppression, malignancy, pregnancy, or postpartum	metastatic disease, CNS infection, CVST, RCVS, IIH
N	Neurologic signs or symptoms	neurologic deficits or atypical or prolonged neurologic symptoms, or both	neoplastic, inflammatory, infectious, or vascular CNS disease
O	Onset (late)	headache onset after age 50 years	neoplastic, inflammatory, or infectious CNS disease, giant cell arteritis
O	Onset (sudden)	thunderclap headache with onset to maximum intensity in less than 60 seconds	subarachnoid hemorrhage, CVST, RCVS, arterial dissection
P	Papilledema	optic disc swelling, with or without pulsatile tinnitus, diplopia, transient visual obscuration, and weight gain	increased intracranial pressure (mass lesion, hemorrhage, edema, CVST, IIH)
P	Postural aggravation	headache triggered or worsened by standing up or lying down	intracranial hypotension or intracranial hypertension
P	Precipitated by valsalva	headache triggered by valsalva (coughing, exercise, intercourse)	Chiari malformation, mass lesion in posterior fossa
P	Pattern changing, or progressive	change in previously stable pattern of headache, or progressively worsening	any secondary cause