A 37-year-old woman presents with headaches for 6 months. She has been taking analgesics regularly. The headache recently increased in severity for 3 days but was reduced in stopping the analgesic. What is the likely diagnosis?

Explanation

## Correct Answer: A. Medication overuse headache Medication overuse headache (MOH) is a secondary headache disorder triggered by regular, excessive use of analgesics, triptans, ergots, or combination analgesics. The diagnostic hallmark is the **temporal relationship between drug overuse and headache escalation**, combined with **improvement upon drug withdrawal**. This patient presents the classic triad: (1) chronic headache for ≥6 months, (2) regular analgesic use, and (3) **acute worsening that resolves within 72 hours of stopping the medication**. According to ICHD-3 criteria, MOH is diagnosed when headache occurs on ≥15 days/month in a patient taking acute medication ≥10–15 days/month (depending on drug class) for >3 months, with improvement after withdrawal. The pathophysiology involves central sensitization and altered pain modulation from chronic medication exposure. In Indian clinical practice, MOH is increasingly common due to over-the-counter availability of analgesics and combination drugs (paracetamol + aspirin + caffeine). The key discriminator here is the **rapid improvement upon cessation**—this is pathognomonic for MOH and distinguishes it from primary headache disorders, which persist regardless of medication changes. ## Why the other options are wrong **B. Cluster headache** — Cluster headache presents with **unilateral orbital pain, autonomic features (lacrimation, nasal congestion, ptosis), and episodic patterns (weeks to months of daily attacks followed by remission)**. It does NOT respond to simple analgesics and is NOT triggered by medication overuse. The patient's 6-month continuous course and analgesic responsiveness rule out cluster headache entirely. **C. Tension headache** — Tension headache is **bilateral, pressing, non-pulsatile, and typically mild-to-moderate in severity**. Critically, it does NOT improve with analgesic withdrawal—in fact, patients with chronic tension headache often require ongoing medication management. The **acute worsening followed by rapid improvement upon stopping medication** is incompatible with primary tension headache pathophysiology. **D. Chronic migraine** — Chronic migraine involves ≥15 headache days/month for ≥3 months with migraine features (unilateral, pulsatile, nausea, photophobia). However, chronic migraine **persists despite medication withdrawal** and often requires preventive therapy (propranolol, amitriptyline). The **resolution of headache within days of stopping analgesics** is inconsistent with chronic migraine, which would continue or worsen without proper prophylaxis. ## High-Yield Facts - **MOH diagnostic threshold**: ≥15 headache days/month + acute medication use ≥10–15 days/month for >3 months (ICHD-3). - **Medication classes implicated**: Simple analgesics (paracetamol, aspirin), NSAIDs, triptans, ergots, and combination analgesics—all carry equal risk in India. - **Withdrawal headache**: Typically peaks 24–48 hours after stopping medication, then resolves within 7 days; this temporal pattern is diagnostic. - **Rebound vs. MOH**: Rebound is acute worsening during overuse; MOH is the chronic state that improves only after prolonged withdrawal. - **Indian context**: Over-the-counter fixed-dose combinations (paracetamol + aspirin + caffeine) are major culprits; patient education on safe analgesic use is critical. ## Mnemonics **MOH = Medication + Overuse + Headache (temporal triad)** **M**edication overuse (≥10–15 days/month) → **O**veruse headache (≥15 days/month) → **H**eadache improves on **W**ithdrawal. Use this to remember: the diagnosis requires BOTH chronic overuse AND improvement with cessation. **ICHD-3 MOH Rule: 3-10-15** **3** months of overuse, **10–15** days/month of acute medication (varies by class), **15** headache days/month. Rapid recall for exam: if all three numbers align, think MOH. ## NBE Trap NBE often pairs MOH with chronic migraine or tension headache to test whether students recognize that **primary headaches persist despite medication changes**, whereas MOH uniquely improves upon withdrawal. The trap is selecting "chronic migraine" if the student forgets that migraine requires preventive therapy and does not resolve by simply stopping analgesics. ## Clinical Pearl In Indian outpatient practice, MOH is frequently missed because patients self-medicate with over-the-counter analgesics and never report the medication history unless directly asked. A simple rule: **any patient with chronic daily headache + regular analgesic use should be counseled on medication withdrawal first, before escalating to imaging or preventive therapy**. This approach saves cost and often resolves the headache within a week. _Reference: Harrison Ch. 424 (Headache); ICHD-3 Diagnostic Criteria for Medication Overuse Headache_