Headache Study Guide

📖 Core Concepts Headache (cephalalgia) – pain in the face, head, or neck. Primary vs. Secondary – Primary: benign, not caused by another disease (migraine, tension‑type, cluster). Secondary: result of another disorder (infection, trauma, vascular, tumor, medication‑overuse). Red‑flag symptoms – clinical clues that a headache may be secondary and warrant urgent work‑up (sudden “thunderclap”, onset > 40 yr, first/worst/changed pattern, systemic or neurologic signs). Pain‑sensitive structures – extracranial arteries, meninges, cranial/spinal nerves, muscles, venous sinuses; the brain parenchyma itself lacks pain receptors. Migraine aura – visual or sensory disturbance occurring 30–60 min before headache, caused by cortical spreading depression. --- 📌 Must Remember Prevalence – 64–77 % of adults experience a headache; 1 %–5 % of ED headaches have a serious cause. POUND mnemonic (Migraine vs. Tension‑Type) Pulsatile quality One‑day duration (4–72 h) Unilateral location Nausea/vomiting Disabling intensity SSNOOP red‑flag mnemonic Systemic symptoms/disease Significant neurologic signs New onset or change in pattern Onset sudden (“thunderclap”) Onset after age 40 (or 50 in some guidelines) Previous history (first, worst, or different) Imaging hierarchy – Non‑contrast CT first for acute severe headache; MRI for tumors, posterior fossa, subtle lesions. Acute migraine treatment – NSAIDs/acetaminophen for mild‑moderate; triptans (5‑HT₁B/₁D agonists) for moderate‑severe; add antiemetic if vomiting. Preventive migraine – ≥4 attacks/month, >12 h attacks, or disabling attacks → beta‑blocker, antidepressant, anticonvulsant, or CGRP monoclonal antibody. Cluster headache acute abort – sub‑cutaneous sumatriptan or high‑flow oxygen (12–15 L/min, 15 min). Chronic tension‑type – amitriptyline (tricyclic) is first‑line preventive. --- 🔄 Key Processes Evaluating a New/Changed Headache Take detailed history (pattern, triggers, associated symptoms). Apply SSNOOP to screen for red flags. Perform focused neurologic exam (cranial nerves, strength, sensation, papilledema). If any red flag → urgent neuroimaging (CT → MRI if needed). Migraine Pathophysiology Trigger → cortical spreading depression → aura. Activation of trigeminovascular system → release of CGRP, substance P → vasodilation & inflammation → headache pain. Triptans block 5‑HT₁B/₁D receptors → vasoconstriction & inhibition of neuropeptide release. Cluster Headache Cycle Hypothalamic circadian rhythm → periodic attacks at the same time each day. Trigeminal autonomic activation → unilateral periorbital pain + tearing, nasal congestion. Acute abort → oxygen or sumatriptan; preventive → verapamil. --- 🔍 Key Comparisons Migraine vs. Tension‑Type Pulsatile vs. band‑like pressure Unilateral vs. bilateral Nausea/photophobia vs. absent nausea/photophobia Primary vs. Secondary Headache Benign, no underlying disease vs. symptom of infection, trauma, vascular event, tumor, medication‑overuse CT vs. MRI CT: rapid, best for acute bleed, bone detail. MRI: superior for tumors, posterior fossa, subtle parenchymal lesions. --- ⚠️ Common Misunderstandings “All severe headaches are dangerous.” → Only thunderclap or those with red flags need emergent work‑up; many severe migraines are primary. “If imaging is normal, headache is benign.” → Normal imaging rules out structural lesions but does not confirm a primary headache; diagnosis relies on history and exam. “Triptans are contraindicated in all vascular disease.” → Absolute contraindication only with uncontrolled coronary disease or certain vasculopathies; many patients with migraine and stable hypertension can use them safely. --- 🧠 Mental Models / Intuition “Red‑flag = alarm bell” – Treat any SSNOOP item as a trigger to order imaging, regardless of how typical the headache sounds. “Migraine = nerve‑vascular cascade” – Imagine a wave (cortical spreading depression) that flips a switch, turning on the trigeminovascular system → headache. “Cluster = clockwork pain” – Picture a clock; attacks strike at the same hour each day, hinting at hypothalamic timing. --- 🚩 Exceptions & Edge Cases Primary thunderclap headache – sudden severe headache without secondary cause; still requires imaging to exclude bleed before labeling primary. Medication‑overuse headache – paradoxical worsening despite frequent analgesic use; stopping overused meds is essential. Pregnant migraine – acetaminophen preferred; triptans used only when benefits outweigh risks. --- 📍 When to Use Which Imaging: Use CT first if acute, sudden severe headache or suspicion of bleed; switch to MRI for suspected tumor, posterior fossa, or when CT is negative but suspicion remains. Acute migraine meds: NSAID/acetaminophen for mild‑moderate; triptan (oral or parenteral) for moderate‑severe or when nausea limits oral intake. Preventive therapy: Choose beta‑blocker if comorbid hypertension; amitriptyline if insomnia or depressive symptoms; CGRP monoclonal antibody if ≥4 attacks/month and other preventives fail. Cluster abort: High‑flow oxygen first; if inadequate, add sub‑Q sumatriptan. --- 👀 Patterns to Recognize Unilateral, pulsating, nausea + photophobia → classic migraine (apply POUND). Bilateral, constant “band” pressure, no nausea → tension‑type. Short (15–180 min), periorbital pain with tearing/nasal congestion → cluster headache. Sudden peak in seconds (“thunderclap”) → consider subarachnoid hemorrhage or primary thunderclap; image emergently. --- 🗂️ Exam Traps “Any headache with photophobia is migraine.” – Tension‑type can occasionally have mild photophobia; rely on the full POUND pattern. “Normal CT rules out secondary headache.” – CT may miss early ischemia, small tumors, or CSF leaks; consider MRI if suspicion persists. “All patients with cluster headache need chronic oxygen therapy.” – Oxygen is for acute abort; preventive therapy is verapamil or lithium. “Medication‑overuse headache is treated with more analgesics.” – The correct approach is to withdraw the overused medication, not add more. ---