Overview

• Most common primary headache disorder; lifetime prevalence ~30–78%
• Often underdiagnosed — many patients self-treat and never present to a physician
• Pathophysiology is incompletely understood — peripheral myofascial mechanisms in episodic form; central sensitization in chronic form

ICHD-3 Diagnostic Criteria

• At least 10 episodes fulfilling below criteria
• Duration: 30 minutes to 7 days
• At least 2 of the following 4 characteristics:
  • Bilateral location
  • Pressing or tightening (non-pulsating) quality
  • Mild or moderate intensity
  • Not aggravated by routine physical activity (walking, climbing stairs)
• Both of the following:
  • No nausea or vomiting
  • No more than one of photophobia or phonophobia (not both)

Subtypes

• Infrequent episodic TTH: <1 day/month (<12 days/year)
• Frequent episodic TTH: 1–14 days/month for ≥3 months (12–180 days/year)
• Chronic TTH: ≥15 days/month for >3 months (>180 days/year)
• Each subtype further specified ± pericranial tenderness

Examination Findings

• Pericranial tenderness on manual palpation — most significant abnormal finding
• Increased tenderness in temporalis, masseter, sternocleidomastoid, trapezius, and suboccipital muscles
• Neurologic exam is normal — any focal findings mandate workup for secondary causes

Treatment

Acute Treatment

• Simple analgesics: NSAIDs (ibuprofen 400–800 mg, naproxen 500 mg), acetaminophen 1000 mg
• Aspirin 500–1000 mg is also effective
• Limit use to <15 days/month to avoid medication overuse headache
• Triptans are not indicated for pure TTH

Preventive Treatment (for Chronic TTH)

• Amitriptyline 25–75 mg at bedtime — best-studied preventive; first-line
• Other TCAs: nortriptyline (less sedating)
• Mirtazapine, venlafaxine — second-line options
• Non-pharmacologic: physical therapy, stress management, biofeedback, cognitive behavioral therapy

TTH vs. Migraine

Definition & Key Features

• Daily and unremitting headache from onset (or becoming unremitting within 24 hours of onset)
• The patient can clearly recall the exact date the headache started — this is the hallmark diagnostic feature
• Present for >3 months
• The headache phenotype itself is non-specific — it may resemble either chronic migraine or chronic TTH

ICHD-3 Criteria

• Persistent headache fulfilling criteria B and C
• B: Distinct and clearly remembered onset, with pain becoming continuous and unremitting within 24 hours
• C: Present for >3 months
• Not better accounted for by another ICHD-3 diagnosis

Triggers & Associations

• Viral illness (most common reported trigger — ~30%); often an upper respiratory infection or flu-like illness
• Extracranial surgery
• Stressful life event
• May occur without identifiable precipitant
• Proposed mechanisms: persistent CNS inflammation, glial activation post-infection

Clinical Subtypes

• Self-limiting subtype: resolves spontaneously within months to years without treatment
• Refractory subtype: resistant to aggressive treatment — unfortunately more common

Workup & Differential

• NDPH is a diagnosis of exclusion — must rule out secondary causes of daily headache
• MRI brain with gadolinium: exclude mass, SIH (pachymeningeal enhancement, brain sag), CVT
• MRV: if suspicion for CVT
• LP with opening pressure: exclude elevated ICP (IIH) or low-pressure headache (SIH)
• Medication overuse headache: must exclude — screen for analgesic use ≥10–15 days/month
• Labs: ESR/CRP (giant cell arteritis if ≥50 years old), CBC, metabolic panel

Treatment

• No proven specific therapy; often highly refractory
• Empiric migraine preventives: topiramate, amitriptyline, gabapentin, venlafaxine
• OnabotulinumtoxinA if migraine-like phenotype
• Nerve blocks (greater occipital nerve) — may provide temporary relief
• Doxycycline has been tried based on neuroinflammatory hypothesis

Clinical Features

• Brought on by Valsalva maneuvers: coughing, straining, sneezing, laughing, bending, lifting
• Bilateral, often posterior, sudden onset
• Duration: seconds to 30 minutes (may linger up to 2 hours)
• Typically affects patients >40 years old
• No associated autonomic features

Mandatory Workup

• MRI brain (with craniocervical junction views) is mandatory — must exclude Chiari type I malformation
• Secondary cough headache (due to Chiari) is more common than primary cough headache
• Other secondary causes: posterior fossa tumor, CSF leak, platybasia, basilar impression
• Chiari I: cerebellar tonsils ≥5 mm below the foramen magnum

Treatment

• Indomethacin 25–50 mg TID — often effective
• Acetazolamide, topiramate, and lumbar puncture (therapeutic) have been reported helpful
• If secondary to Chiari → posterior fossa decompression is definitive treatment

Clinical Features

• Brought on by sustained strenuous physical exercise (running, weightlifting, rowing)
• Pulsating quality
• Duration: 5 minutes to 48 hours
• Occurs only during or after exercise
• More common in hot weather or at high altitude

Workup

• First presentation: must exclude SAH (CT ± LP) and arterial dissection (CTA/MRA head and neck)
• Cardiac evaluation if exertional — exclude cardiac cephalgia (rare; headache as anginal equivalent)
• Consider pheochromocytoma if associated with hypertension and diaphoresis

Treatment

• Indomethacin 25–50 mg taken 30–60 minutes before exercise — first-line prophylaxis
• Adequate warm-up before strenuous activity
• Avoid exercising in extreme heat
• Usually self-limited; many patients improve over months to years

Subtypes

• Type 1 — Preorgasmic headache:
  • Dull, bilateral, aching head/neck pain that builds gradually with increasing sexual arousal
  • Associated with contraction of head and neck muscles
• Type 2 — Orgasmic headache:
  • Explosive, thunderclap-type headache occurring at or just before orgasm
  • Severe intensity, often occipital
  • Duration: minutes to hours (up to 72 hours)

Critical Workup

• Type 2 (orgasmic/thunderclap) on first episode: must exclude SAH, arterial dissection, and RCVS
• CT head → LP if CT negative → CTA/MRA
• RCVS can present with recurrent thunderclap headaches triggered by sexual activity
• Once secondary causes are excluded and a pattern of recurrent episodes is established → primary diagnosis can be made

Treatment

• Indomethacin 25–50 mg taken 30–60 minutes before sexual activity
• Propranolol 40–80 mg as an alternative (taken 1 hour before activity or as daily prophylaxis)
• Triptans taken before activity may be effective in some patients
• Benign and self-limited in most cases

Definition

• Severe headache reaching maximum intensity within 60 seconds (“worst headache of my life”)
• Duration: ≥5 minutes
• Primary thunderclap headache is a diagnosis of exclusion — secondary causes must be ruled out first

Secondary Causes to Exclude

• SAH — most critical to rule out
• RCVS (reversible cerebral vasoconstriction syndrome) — recurrent thunderclap headaches over days to weeks
• Cerebral venous thrombosis
• Cervical artery dissection (carotid or vertebral)
• Pituitary apoplexy — hemorrhage into pituitary adenoma; headache + visual field defect + ophthalmoplegia
• Hypertensive crisis / posterior reversible encephalopathy syndrome (PRES)
• Spontaneous intracranial hypotension — if positional component
• Colloid cyst of the third ventricle — positional thunderclap HA with acute hydrocephalus

Workup Algorithm

• Step 1: Non-contrast CT head (sensitivity ~95% within 6 hours of SAH, drops to ~50% at 1 week)
• Step 2: If CT is negative → LP (looking for xanthochromia, elevated RBC count that does not clear)
• Step 3: CTA or MRA — evaluate for aneurysm, dissection, RCVS (multifocal segmental vasoconstriction)
• MRI brain: look for PRES, CVT, pituitary apoplexy, hemorrhagic lesions
• MRV: if CVT suspected

Clinical Features

• “Alarm clock headache” — wakes the patient from sleep at a consistent time each night
• Age of onset: >50 years (mean ~60 years)
• Frequency: ≥10 episodes per month (often nightly)
• Duration: 15 minutes to 4 hours after waking
• Usually bilateral, dull, mild-to-moderate intensity
• No autonomic features (no lacrimation, rhinorrhea, conjunctival injection, ptosis)
• Not side-locked (unlike cluster headache)

Hypnic Headache vs. Cluster Headache

Treatment

• Lithium carbonate 150–300 mg at bedtime — first-line treatment
• Caffeine (cup of coffee or 40–60 mg caffeine tablet at bedtime) — simple and often effective
• Melatonin 3–5 mg at bedtime — may help some patients
• Indomethacin — less consistently effective than for other primary headaches
• Flunarizine has also been used

Clinical Features

• “Ice-pick headache” — spontaneous, ultrabrief stabbing pains
• Duration: seconds (typically ≤3 seconds per stab; single or in series)
• Location: orbito-temporal region (V1 distribution), but can occur anywhere on the head
• May be multifocal and shift locations
• No associated autonomic features
• Often occurs in patients with a history of migraine (~40%)
• Irregular frequency — once to many times per day

Treatment

• Indomethacin 25–50 mg TID — treatment of choice
• COX-2 inhibitors (celecoxib) as an alternative
• Melatonin may be tried in patients who cannot tolerate indomethacin
• Often self-limited; may not require treatment if infrequent

Clinical Features

• Pain localized to a fixed, coin-shaped area of the scalp
• Diameter: typically 2–6 cm, round or elliptical
• May be continuous or intermittent
• Intensity: mild-to-moderate, sometimes with superimposed exacerbations of sharp or stabbing pain
• Trophic changes in the affected area may occur — allodynia, paresthesias, hypoesthesia, or hair loss
• Most commonly affects the parietal region
• The area of pain can be outlined by the patient with precision

Workup

• Consider neuroimaging to exclude underlying skull lesion (metastasis, meningioma, Paget disease) if atypical features present
• Skull radiograph or CT of the skull may reveal bony pathology
• Skin biopsy if dermatologic pathology is suspected

Treatment

• Gabapentin 300–1200 mg/day — first-line
• Topiramate 50–100 mg/day
• Local treatments: lidocaine patches, capsaicin cream, botulinum toxin injection over the affected area
• Tricyclic antidepressants (amitriptyline) may help
• Indomethacin is less reliably effective than for other primary headaches