Diagnostic Algorithms for Primary Headaches: A Step-by-Step Flowchart

Evaluating headache complaints systematically prevents diagnostic oversight and over-investigation. When evaluating a suspected primary headache, follow this clinical decision tree:

1. Assess Attack Frequency: Determine if the headache presents on $>15\text{ days per month}$ (high frequency/chronic) or $<15\text{ days per month}$ (low to moderate frequency).

2. Evaluate Attack Duration:

   • If duration is $>4\text{ hours}$ per day in high-frequency patterns, classify among Chronic Tension-Type Headache (CTTH), Chronic Migraine (CM), Hemicrania Continua (HC), or New Daily Persistent Headache (NDPH).

   • If duration is $<4\text{ hours}$, proceed to trigger assessment.

3. Identify Physical Triggers:

   • Triggered by cough, exercise, or Valsalva maneuvers: Evaluate for short-duration primary triggered headaches (e.g., primary cough headache, primary exercise headache, hypnic headache, or primary sexual headache).

   • Non-triggered short-duration attacks: Evaluate for Trigeminal Autonomic Cephalalgias, including Cluster Headache (CCH/ECH), Paroxysmal Hemicrania (CPH/EPH), SUNCT, episodic TTH, or episodic migraine.

Using structured diagnostic flowcharts streamlines history-taking in high-volume clinical settings.