Residency · Residency · Family Medicine

Headache: Red Flags, Diagnosis, and Acute Management

Overview

Headache is one of the most frequent complaints encountered in primary care. Over 90% of headaches are primary in nature, encompassing migraine, tension-type headache, and cluster headache, but timely recognition of secondary headache red flags is critical because the consequences of missing a dangerous diagnosis can be catastrophic. Effective management requires accurate classification of the headache type and deployment of targeted therapy matched to attack severity.

Primary Headache Classification

Migraine

Migraine affects approximately 12% of the general population and is three times more common in women than men. Migraine without aura accounts for about 75% of cases and presents with unilateral, pulsating pain of moderate to severe intensity lasting 4 to 72 hours. Migraine with aura, making up the remaining 25%, is preceded or accompanied by visual phenomena such as scintillating scotomata and fortification spectra, or by sensory or language disturbance lasting 5 to 60 minutes. Associated features include nausea, vomiting, photophobia, phonophobia, and worsening with physical activity. The ICHD-3 diagnostic criteria require at least five attacks meeting these characteristics.

Tension-Type Headache (TTH)

Tension-type headache is the most common primary headache disorder. It produces bilateral, pressing or tightening pain of mild to moderate intensity, lasting anywhere from 30 minutes to 7 days. Unlike migraine, tension-type headache does not cause nausea or vomiting, and at most one of photophobia or phonophobia may be present, but not both. The headache is not aggravated by routine physical activity. Tension-type headache is classified as episodic when occurring fewer than 15 days per month and chronic when reaching 15 or more days per month.

Cluster Headache

Cluster headache predominantly affects men, with a 3-to-1 male predominance and typical onset between ages 20 and 40. Attacks are strictly unilateral, centered around the periorbital and temporal region, and extraordinarily severe, lasting 15 to 180 minutes. Accompanying ipsilateral autonomic features include lacrimation, conjunctival injection, nasal congestion or rhinorrhea, ptosis, miosis, eyelid edema, and forehead or facial sweating. A distinguishing behavioral feature is marked restlessness and agitation during attacks, in contrast to migraine patients who prefer quiet and stillness. Cluster periods typically last 2 to 12 weeks with one to eight daily attacks, followed by periods of remission.

Other Trigeminal Autonomic Cephalalgias

Paroxysmal hemicrania presents with shorter attacks lasting 2 to 30 minutes occurring more frequently, and it demonstrates an absolute response to indomethacin. SUNCT and SUNA produce very brief attacks lasting 1 to 600 seconds at very high frequency. Hemicrania continua causes continuous unilateral headache and, like paroxysmal hemicrania, is characteristically responsive to indomethacin.

Red Flags (SNOOP10 Mnemonic)

The SNOOP10 mnemonic provides a systematic framework for identifying dangerous secondary headaches. "S" stands for systemic symptoms such as fever and weight loss, or systemic disease such as HIV or malignancy. "N" indicates neurologic symptoms or abnormal signs including focal deficits, altered consciousness, or seizures. The first "O" refers to sudden onset, specifically thunderclap headache reaching peak intensity within seconds, which is subarachnoid hemorrhage until proven otherwise. The second "O" denotes older age, with new headache onset after age 50 raising concern for giant cell arteritis or malignancy. The remaining letters, all "P," cover prior headache history change with a significant shift in pattern, frequency, or severity; positional component where pain worsening on standing suggests low CSF pressure and worsening when supine suggests raised intracranial pressure; precipitation by Valsalva, cough, or exertion suggesting Chiari malformation or posterior fossa lesion; papilledema indicating raised intracranial pressure; progressive headache over weeks suggesting a mass lesion or chronic subdural hematoma; pregnancy or postpartum raising concern for preeclampsia, cerebral venous thrombosis, or posterior reversible encephalopathy syndrome; and painful eye with autonomic features requiring exclusion of acute angle-closure glaucoma.

Secondary Headache Evaluation

Thunderclap Headache

Thunderclap headache reaches peak intensity within seconds to one minute and demands urgent evaluation. CT of the head without contrast is approximately 98% sensitive for subarachnoid hemorrhage within 6 hours. If CT is negative but clinical suspicion remains, lumbar puncture should be performed to look for xanthochromia and elevated red blood cells, or CT angiography may be pursued. The differential also includes reversible cerebral vasoconstriction syndrome, cervical artery dissection, and pituitary apoplexy.

Giant Cell Arteritis (Temporal Arteritis)

Giant cell arteritis should be suspected in any patient over 50 presenting with new headache, scalp tenderness, jaw claudication, or visual disturbance. Laboratory findings include ESR above 50 mm/hr, elevated CRP, and thrombocytosis. Temporal artery biopsy remains the gold standard for diagnosis, though ultrasound demonstrating the halo sign is increasingly used. High-dose prednisone at 60 mg daily must be started immediately to prevent irreversible vision loss, and treatment should never be delayed to await biopsy results, as steroids do not significantly alter biopsy findings for 2 to 4 weeks.

Idiopathic Intracranial Hypertension (IIH)

Idiopathic intracranial hypertension classically affects young obese women and presents with headache, visual obscurations, pulsatile tinnitus, and papilledema. MRI findings include empty sella, flattened posterior globes, and dilated optic nerve sheaths. Lumbar puncture demonstrates elevated opening pressure above 25 cm H2O with normal CSF composition. Treatment centers on weight loss and acetazolamide, with serial visual field monitoring to track optic nerve function. Refractory cases may require optic nerve sheath fenestration or CSF shunting.

Neuroimaging Indications

Neuroimaging is warranted when any red flag feature is present, when new headache develops after age 50, in thunderclap headache, with focal neurologic deficits, or with a significant change in an established headache pattern. MRI is preferred over CT for most non-emergent evaluations because of its superior sensitivity for posterior fossa pathology, white matter lesions, and pituitary abnormalities. CT is reserved for acute emergencies when subarachnoid hemorrhage, intracranial hemorrhage, or fracture is suspected.

Acute Migraine Treatment

Stepped Care vs. Stratified Care

Stratified care, in which treatment intensity is matched to attack severity from the outset, has been shown to be superior to the traditional stepped approach of starting with simple analgesics and escalating only when they fail. For mild attacks, simple analgesics are appropriate, but moderate to severe attacks should receive migraine-specific therapy as first-line treatment.

NSAIDs and Acetaminophen

Ibuprofen at 400 to 800 mg, naproxen at 500 to 750 mg, and acetaminophen at 1000 mg are effective for mild to moderate migraine, particularly when taken early in the attack. The combination of acetaminophen, aspirin, and caffeine (marketed as Excedrin Migraine) is effective for mild to moderate attacks as well.

Triptans

Triptans are first-line therapy for moderate to severe migraine, with seven agents available in the class. Sumatriptan at 50 to 100 mg orally is the most commonly prescribed, with the 6 mg subcutaneous formulation and nasal spray offering the fastest onset. Rizatriptan at 10 mg is available as an orally disintegrating tablet, and eletriptan at 40 mg offers the highest consistency of response. Triptans act as 5-HT1B/1D agonists, producing vasoconstriction and trigeminal inhibition. They are most effective when taken early in the attack and can be repeated once after 2 hours. Contraindications include uncontrolled hypertension, coronary artery disease, prior stroke, hemiplegic migraine, and basilar migraine. The number needed to treat is approximately 3 to 4 for 2-hour pain freedom.

Gepants (CGRP Receptor Antagonists)

Ubrogepant at 50 to 100 mg and rimegepant at 75 mg represent a major advance in acute migraine treatment. These oral CGRP receptor antagonists have no vasoconstrictive effects, making them safe in patients with cardiovascular disease who cannot use triptans. The number needed to treat is approximately 5 to 6 for 2-hour pain freedom. Rimegepant has the additional advantage of being approved for migraine prevention when dosed every other day.

Ditans

Lasmiditan at 50 to 200 mg is a 5-HT1F agonist with no vasoconstrictive properties, providing another alternative for patients with cardiovascular contraindications to triptans. Common side effects include sedation and dizziness, and it is classified as Schedule V due to driving impairment, with an 8-hour post-dose driving restriction.

Anti-Emetics

Metoclopramide at 10 mg and prochlorperazine at 10 mg provide dual benefit for both nausea and headache in migraine attacks. Ondansetron addresses nausea effectively but does not have independent antimigrainous benefit.

Status Migrainosus

Status migrainosus refers to migraine lasting more than 72 hours despite treatment. Management includes IV fluid, ketorolac 30 mg IV or IM, prochlorperazine 10 mg IV, dexamethasone 10 mg IV (which reduces recurrence risk), and magnesium 2 g IV. Opioids should be avoided, as they demonstrate inferior efficacy and increase the risk of migraine chronification.

Tension-Type Headache Treatment

Simple analgesics are the mainstay of acute treatment, including ibuprofen at 400 mg, acetaminophen at 1000 mg, and aspirin at 650 to 1000 mg. Opioids and butalbital-containing compounds should be avoided. For chronic tension-type headache, amitriptyline at 10 to 75 mg at bedtime is the preferred preventive agent, complemented by stress management and physical therapy.

Cluster Headache Treatment

Acute treatment of cluster headache relies on high-flow oxygen at 12 to 15 L/min via non-rebreather mask for 15 minutes, with a number needed to treat of approximately 3, and sumatriptan 6 mg subcutaneously for the fastest relief. Transitional preventive therapy includes a prednisone taper and greater occipital nerve block. Maintenance prevention centers on verapamil at 240 to 960 mg daily, which is first-line though requires ECG monitoring for heart block. Lithium is an alternative, and galcanezumab, an anti-CGRP monoclonal antibody, is FDA-approved for episodic cluster headache.

Medication Overuse Headache (MOH)

Medication overuse headache develops when headache occurs 15 or more days per month in the setting of regular overuse of acute medications for more than 3 months. The threshold for overuse varies by medication class: triptans, ergots, opioids, and combination analgesics at 10 or more days per month, and simple analgesics at 15 or more days per month. Treatment involves education, withdrawal of the offending medication, bridge therapy with naproxen, nerve block, or a short steroid course, and initiation of preventive therapy. Prevention requires limiting acute medication use to fewer than 10 days per month.

<image>A visual decision tree for headache evaluation beginning with red flag assessment (SNOOP10), branching into secondary headache workup (imaging, labs, LP) versus primary headache classification. For primary headaches, show the distinguishing features of migraine, tension-type, and cluster headache in parallel columns with key differentiating characteristics, duration, associated features, and first-line acute treatments.</image>

<image>An infographic comparing acute migraine treatment options across three classes: triptans, gepants, and ditans. For each class show mechanism of action, onset of action, NNT for 2-hour pain freedom, cardiovascular safety profile, common side effects, and ideal patient population. Include a visual representation of the serotonin receptor subtypes targeted by each class.</image>

<image>A red flag recognition poster showing the SNOOP10 mnemonic with an icon for each warning feature, the associated dangerous secondary headache diagnosis, and the recommended urgent investigation for each red flag. Highlight thunderclap headache and giant cell arteritis as the two most time-sensitive diagnoses requiring immediate action.</image>

Clinical Pearls

Thunderclap headache is subarachnoid hemorrhage until proven otherwise; CT within 6 hours is approximately 98% sensitive, but lumbar puncture is required if CT is negative and clinical suspicion remains. Giant cell arteritis requires immediate steroids, and treatment should not be delayed to obtain biopsy, as steroids do not significantly alter biopsy results for 2 to 4 weeks. Triptans are most effective when taken early during a migraine attack, and delayed dosing substantially reduces efficacy. Gepants are a major advance for patients with cardiovascular disease who cannot use triptans, and they also have preventive utility. Opioids and butalbital compounds should generally be avoided for headache, as they increase chronification risk and medication overuse headache. Any patient using acute headache medications more than 10 days per month is at risk for medication overuse headache, which is the most common cause of chronic daily headache. Cluster headache patients are restless and agitated during attacks, pacing or rocking, while migraine patients prefer quiet and stillness, and this behavioral difference is a valuable diagnostic clue. If indomethacin completely resolves a unilateral headache, paroxysmal hemicrania or hemicrania continua should be considered, as these are the classic indomethacin-responsive headaches.

References

• Headache Classification Committee of the IHS. ICHD-3. Cephalalgia. 2018
• AHS Consensus Statement: Acute Treatment of Migraine in Adults. Headache. 2021
• Dodick DW. Ubrogepant for Acute Migraine (ACHIEVE I/II). JAMA. 2019
• May A et al. Cluster Headache. Nat Rev Dis Primers. 2018
• Lipton RB et al. Rimegepant for Acute Treatment and Prevention of Migraine. NEJM. 2021
• Robbins MS et al. AHS Position Statement: Neuroimaging for Headache. Headache. 2020
• Do TP et al. Red and Orange Flags for Secondary Headaches in Clinical Practice. Neurology. 2019

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