Red flags in headache diagnosis

Sudden-onset (“thunderclap”)

Consider:

• Subarachnoid hemorrhage
• Arterial dissection
• Aneurysm thrombosis or expansion
• Venous sinus thrombosis
• Hypertensive crisis
• Reversible cerebral vasoconstriction syndrome
• Retroclival hematoma
• Pituitary apoplexy
• Spontaneous intracranial hypotension
• Colloid cyst of the 3rd ventricle
• Meningitis
• Sinusitis
• Primary headache syndromes:
  • Cough, sexual or exertional headache
  • Primary (idiopathic) thunderclap headache

Worsening pattern

Consider:

• Subdural hematoma
• Medication-induced
• Mass lesion

Focal neurologic signs

Consider:

• Mass lesion
• AVM
• Collagen vascular disorder

Papilledema

Consider:

• Mass lesion
• Meningitis
• Encephalitis
• Idiopathic intracranial hypertension
• Venous sinus thrombosis

HIV, cancer or other systemic illness

Consider:

• Meningitis
• Encephalitis
• Systemic infection
• Lyme disease
• Vasculitis
• Collagen vascular disease

Triggering by Valsalva, exertion or cough

Consider:

• Mass lesion
• Subarachnoid hemorrhage
• Posterior fossa pathology

Pregnancy or postpartum state

Consider:

• Venous sinus thrombosis
• Arterial dissection
• Pituitary apoplexy