Diagnostic Approach

The diagnosis of headache disorders is based primarily on the clinical presentation and physical exam. Diagnostic criteria have been established to guide diagnosis and classification.

The key priorities in diagnosing acute headache are:

• Identify red flag symptoms that can indicate dangerous secondary headache disorders through focused history and physical exam. Red flags include:
  • New onset or thunderclap headache
  • Fever
  • Neurological deficits
  • Impaired consciousness
  • Nuchal rigidity
  • Hypertension
  • Papilledema
  • Head trauma

• Perform targeted diagnostic testing based on concerning symptoms and history:
  • Neuroimaging:
    • CT head without contrast to assess for hemorrhage or mass effect
    • CT or MR angiography to assess for vascular abnormalities
    • MRI brain with and without contrast for detailed structural evaluation
    • LP if concerned for subarachnoid hemorrhage and CT nondiagnostic
  • Infectious workup:
    • CBC, peripheral blood culture
    • LP with opening pressure, cell count, culture
    • Consider viral PCR, fungal tests
  • Inflammatory/autoimmune labs:
    • ESR, CRP
    • Rheumatologic serologic tests
  • Toxicology screen if concerned for substance use

• Characterize headache profile to distinguish among primary headache types:
  • Migraine – moderate/severe intensity, unilateral, pulsating quality, nausea
  • Tension – mild/moderate intensity, bilateral tight band sensation
  • Cluster – severe, unilateral, periocular, restlessness

• Inquire about similar past headache episodes and response to prior treatments
• Carefully review medications that could cause secondary headache
• Address psychosocial factors that could contribute to headache disorders

Accurate diagnosis guides both appropriate symptom control and identification of secondary headaches requiring emergency management. A high index of suspicion along with judicious use of diagnostic testing is key.