30.1 Pathophysiology

• Sustained muscle contraction (tension headache)

• NO production or ischemia—causative of muscle contraction?

• Vasodilation of intracranial arteries—stimulates V n pathways → release vasoactive peptides that increase pain response

• 5-HT receptor subtypes in vascular walls responsible for vasodilation

• If neuropeptides released (e.g., substance P) → mucosal inflammation

• Direct nerve pressure may induce nociceptor activity

• Agents that can trigger vasodilation:

Hypoxia

CO

Caffeine withdrawal

Acute alcohol withdrawal

Oral contraceptive pill

Hypoglycemia

Antihypertensives

Chinese food ingredients, e.g., nitroglycerin, monosodium glutamate

• Defective release of endogenous opiates (migraine)

• Lowered cortical pain thresholds (chronic tension headaches)

30.2 Epidemiology

• Headache affects ~40% of the population at some point in their life

• Migraine occurs in 15% of adult population; 3 female: 1 male ratio

• 100,000 absentees from work due to migraine

• Tension headache affects up to 80% of people at some time

• 3% have chronic tension headache for >15 days/month

• Medication overuse headache affects 2% of adults

30.3 Primary Headaches

30.3.1 Migraine-Type Headaches

• Prevalence = 18% women, 6% men

• Peak age of onset = 2nd to 3rd decades

• Severe unilateral throbbing; 40% bilateral

• Sudden onset; last 4 to 72 h

• Often after waking in the morning; or due to stress

• Routine activities exacerbate symptoms

• Coexisting symptoms:

N&V

Photophobia

Phonophobia

• Common family history

30.4 Types of Migraine

30.4.1 Migraine without Aura

• At least 5 attacks fulfilling following criteria and not attributed to another disorder:

Headache attacks lasting 4 to 72 h (untreated or unsuccessfully treated)

Headache has at least 2 of the following characteristics:

– Unilateral location

– Pulsating quality

– Moderate or severe pain intensity

– Aggravation by or causing avoidance of routine physical activity (e.g., walking or climbing stairs)

During headache at least 1 of the following:

– Nausea and/or vomiting

– Photophobia and phonophobia

30.5 Migraine with Aura

• Aura lasts <1 h and immediately precedes cephalalgia

• May be precipitated by changes in female sex hormones, certain foods, or bright lights

• At least two attacks

• Typical aura with migraine headache

Aura consisting of at least 1 of the following, but no motor weakness:

– Fully reversible visual symptoms including positive features (e.g., flickering lights, spots or lines) and/or negative features (i.e., loss of vision)

– Fully reversible sensory symptoms including positive features (i.e., pins and needles) and/or negative features (i.e., numbness)

At least two of the followings:

– Homonymous visual symptoms and/or unilateral sensory symptoms

– At least one aura symptom develops gradually over ≥5 min and/or different aura symptoms occur in succession over ≥5 min

– Each symptom lasts ≥5 and ≤60 min

Headache fulfilling same criteria migraine without aura begins during the aura or follows aura within 60 min

• Typical aura with non-migraine headache

• Typical aura without headache

Headache does not occur during aura nor follow aura within 60 min

Aura otherwise as above with/without speech disturbance