tension headache

**Definition/Epidemiology**: Most common primary headache (lifetime prevalence ~30-78%). Subtypes (ICHD-3): infrequent episodic (<1 day/month), frequent episodic (1-14 days/month), and chronic (≥15 days/month for >3 months). Slight female predominance; onset typically in teens-20s-40s.

**Pathophysiology**: Incompletely understood. Peripheral mechanisms (myofascial/pericranial muscle tenderness, increased sensitivity of nociceptors) likely drive episodic TTH. Central sensitization (impaired descending pain inhibition, sensitization of second-order trigeminal neurons) is thought to underlie chronic TTH. Triggers: stress, sleep deprivation, fatigue, skipped meals, poor posture, eye strain. Note: "muscle contraction/tension" is no longer thought to be the sole cause.

**Clinical features (ICHD-3)**: Duration 30 minutes to 7 days. At least 2 of: bilateral location; pressing/tightening (non-pulsating) quality; mild-to-moderate intensity; NOT aggravated by routine physical activity. Both: no nausea/vomiting (mild nausea allowed in chronic TTH), and no more than one of photophobia or phonophobia. Classically described as a "band-like" or "vise-like" pressure around the head; often with pericranial tenderness. Neurologic exam is normal; no aura.

**Differential/High-yield comparisons**: - Migraine: unilateral, pulsatile, moderate-severe, 4-72 hr, worsened by activity, nausea/vomiting, photophobia AND phonophobia, ± aura. - Cluster headache: severe unilateral periorbital pain, 15-180 min, with autonomic features (lacrimation, rhinorrhea, Horner-like ptosis/miosis), restlessness; male predominance; treat with 100% O2 and sumatriptan; prophylaxis with verapamil. - Medication-overuse headache: chronic daily headache from frequent analgesic/triptan use (≥10-15 days/month). - Red flags (SNOOP): Systemic symptoms (fever, weight loss), Neurologic deficits, Onset sudden (thunderclap → SAH) or after age 50 (giant cell arteritis), Occipital/positional features, Pattern change/Progressive, Papilledema → warrant imaging/workup.

**Diagnosis**: Clinical. Neuroimaging not needed in the absence of red flags.

**Management**: - Acute: NSAIDs (ibuprofen, naproxen, aspirin) or acetaminophen first-line; caffeine combinations can help. Limit use to <2-3 days/week to avoid medication-overuse headache. Triptans are generally ineffective unless coexisting migraine. Avoid opioids and butalbital. - Prophylaxis (frequent/chronic TTH): amitriptyline (TCA) is first-line; alternatives include mirtazapine and venlafaxine. - Non-pharmacologic: stress management, cognitive-behavioral therapy, biofeedback, relaxation, physical therapy, regular sleep/exercise, acupuncture.

**Board pearls**: "Band-like, bilateral, non-pulsatile, no N/V, not worse with activity" = tension headache. Contrast with migraine (worse with activity). Chronic TTH prophylaxis = amitriptyline (whereas migraine prophylaxis = propranolol, topiramate, amitriptyline, CGRP antagonists; cluster = verapamil).