Headache

Headache is a commonly presenting complaint in everyday clinical practice, and, according to the WHO, one of the ten most common causes of functional disability. It may be primary (e.g., tension-type headaches, migraine) or secondary (e.g., following head trauma or infections) in nature. Headache may occur as acute episodes or persist chronically. Chronic headaches, which are associated with a decline in quality of life, have a significant socioeconomic impact. Therefore, chronic headaches should be diagnosed and treated early. Although most episodes of headache are fleeting and harmless, one must always consider potentially life-threatening causes (e.g., subarachnoid hemorrhage, meningitis). Identifying the cause of headaches is often difficult, and requires a detailed clinical history as well as a thorough physical examination. Additional investigation, such as cranial imaging, is only indicated if headache persists despite treatment or when specific clinical features are present that are signs of an underlying disease. This learning card gives an overview of the most common types of headache and serves as a guide to diagnosing different headache disorders.

• Distribution: Headache is a global health problem that affects people of all ages, ethnicities, and regions.
• Worldwide prevalence: 60%
  • Probability of experiencing at least one episode of headache during one's lifetime: > 90%
  • 4% of people experience headaches 15 or more days per month.
• Most common forms of headache
  • Tension-type headache: 60–80% of cases
  • Migraine: 12–14% of cases

References:^[1][2]

Epidemiological data refers to the US, unless otherwise specified.

Type of headache		Common causes
Primary headache		Migraine Tension-type headache Trigeminal autonomic cephalalgias: cluster headaches, paroxysmal hemicrania, hemicrania continua Other primary headaches
Secondary headache	Head and/or cervical trauma	Post-traumatic intracerebral hemorrhage Epidural hemorrhage Subdural hemorrhage
	Vascular disorders in the head and neck region	Temporal arteritis Subarachnoid hemorrhage Cerebral venous thrombosis Pituitary apoplexy Stroke, TIA Aneurysms Carotid/vertebral artery dissection
	Non-vascular intracranial disorders	Raised intracranial pressure Low intracranial pressure (e.g., post-lumbar puncture headache) Brain tumors Aseptic meningitis Post-ictal headache
	Introduction or withdrawal of a substance	Alcohol Food additives (e.g., MSG) Vasopressors (e.g., nicotine) Medication overuse headache Caffeine withdrawal Opioid withdrawal
	Infections	Intracranial infections Meningitis Encephalitis Brain abscess Subdural empyema Systemic infections (e.g., influenza, dengue)
	Disorders of homeostasis	Hypoxia and/or hypercapnia (e.g., high altitude headache) Hypertension Hypoglycemia Hypothyroidism
	Disorders of the eyes, teeth, nasal cavity, neck, and/or paranasal sinuses	Glaucoma Iridocyclitis Refractive errors Rhinosinusitis Cervicogenic headache (e.g., cervical disc disease) Temporomandibular joint disorders
	Psychiatric disorders	Somatization disorder Psychotic disorder
Cranial nerve neuralgias and facial pain		Trigeminal neuralgia, Post-herpetic neuralgia Optic neuritis
Headaches that do not fit any of the patterns above or have an unknown cause are referred to as “unclassified headache disorders.”

References:^[3]

Clinical history
Time	Duration of a single episode Frequency (number of episodes per month) Clinical course (e.g., chronic , acute)
Nature of headache	Localization (e.g., unilateral, bilateral, orbital) Character (e.g., pulsating, stabbing) Intensity (rated on a pain scale ranging from 0 to 10)
Triggers and exacerbating factors	Altered sleep-wake cycle Physical exertion Stress Certain types of food, alcohol Fluctuations in hormone levels: oral contraceptives, menstruation Lying down or standing up
Concomitant symptoms	Nausea Horner syndrome Aura Photopsia
Other relevant aspects	Family history (e.g., familial headache syndromes) Medication history Alcohol consumption Smoking Allergies Hypertension Hypothyroidism
Physical examination
Blood pressure measurement to rule out hypertension and/or a hypertensive crisis Focal neurological deficits are typically present in stroke, intracranial hemorrhage, meningoencephalitis, intracranial space-occupying lesions, and/or cerebral venous sinus thrombosis. Fever usually indicates an infectious cause of headache. Tenderness of pericranial muscles may indicate a tension-type headache. The superficial temporal artery is tender and palpably thickened in the case of temporal arteritis. Trigger points along the course of the trigeminal nerve may be present in the case of trigeminal neuralgia. Painful jaw movement may indicate temporal arteritis or disorders of the temporomandibular joint. Examination of the teeth and oral cavity may reveal dental or maxillary disease. Eyeball tenderness and/or painful ocular movement may indicate raised intra-ocular pressure. Restricted cervical spine mobility may be present in the case of cervicogenic headache. Tenderness over the sinuses is present in the case of sinusitis.

A detailed clinical history helps to identify the underlying cause of headache, especially when neurological examination is normal (e.g., primary headaches)!

A thorough physical examination is important to identify the cause of secondary headache!

References:^[1]

Additional diagnostic tests should be undertaken if any of the following red flags are present:
Severe unrelenting headache Fever Focal neurological deficits Seizures Impaired consciousness Signs of increased intracranial pressure (e.g., loss of consciousness, vomiting, bradycardia) Signs of meningism: neck rigidity, photophobia Psychiatric symptoms Eye pain
Imaging	Additional tests
Cranial CT: to diagnose intracranial hemorrhage Cranial MRI: to diagnose parenchymal lesions Digital subtraction angiography: to diagnose small aneurysms Neck ultrasound: to diagnose arterial dissection Cervical spine x-ray: to rule out degenerative cervical spine pathology X-ray of the paranasal sinuses: to rule out sinusitis	CBC: to identify infections ESR: to diagnose temporal arteritis Fundoscopy: to identify papilledema (possibly due to raised intracranial pressure) Lumbar puncture: to rule out meningitis Thyroid function tests: to rule out hypothyroidism Tonometry: to identify increased intra-ocular pressure EEG: to identify changes in cortical activity

Diagnostic tests are usually not indicated in most cases (especially primary headaches). They are used primarily to evaluate secondary headaches and severe, acute headaches, which may be life-threatening (e.g., subarachnoid hemorrhage, trauma)!

The investigation of choice is determined by the clinical presentation!

Primary headaches

	Sex	Duration	Frequency	Localization	Character	Intensity	Additional symptoms	Triggers/exacerbating factors	Therapy
Tension headache	♂ < ♀	Episodic or chronic	Occasionally to daily	Holocephalic or bifrontal	Compressive, non-pulsating dull pain (band-like)	Mild to moderate	No additional autonomic symptoms	Stress Lack of sleep, fatigue	NSAIDs Tricyclic antidepressants (e.g., amitriptyline)
Migraine	♂ < ♀	4–72 hours	Occasionally to several times a month	60% are unilateral	Pulsating, boring/hammering pain	Moderate to severe	Nausea, vomiting Hyperacusis Photophobia Preceding aura	Stress Fluctuation in hormone levels: oral contraceptives, menstruation Certain types of food (e.g., those containing tyramines or nitrates such as processed meat, chocolate, cheese) Physical exertion	Abortive therapy: NSAIDs, sumatriptan, and/or ergot preparations Antiemetics to control vomiting Migraine prophylaxis Beta blockers (e.g., propanolol) Tricyclic antidepressants (e.g., amitriptyline)
Cluster headache	♂ > ♀ (3:1)	30–180 min	1–3 episodes/24 h	Mostly unilateral	Severe headache that is localized to the periorbital region	Severe	Ipsilateral conjunctival injection and/or epiphora (excessive lacrimation) Rhinorrhea and swelling of nasal mucous membranes Partial horner syndrome (ptosis, miosis) Ipsilateral forehead or facial sweating	Alcohol	Abortive therapy 100% oxygen Ergot preparations and/or sumatriptan Prophylaxis Induction: prednisone Maintenance: verapamil, methysergide, lithium, valproic acid, or topiramate

Secondary headache

The following table deals with secondary causes of headaches, some of which are life-threatening but treatable and should therefore be diagnosed as early as possible.

Causes	Diagnosis	Type of headache	Additional clinical features
Infections	Meningitis	Dull, diffuse (holocephalic) headache that worsens over hours/days	Fever Meningism (neck rigidity, photophobia) Vomiting Other features specific to a certain pathogen (e.g., in the case of viral meningitis: herpangina, parotitis)
	Encephalitis	Acute, diffuse headache that worsens over time	Fever Mild meningism Impaired consciousness Delirium Seizures Focal neurological deficits
Vascular causes	Intracranial hemorrhage	Intracerebral hemorrhage: acute, intense headache that worsens over time	Vomiting Rapidly worsening neurological status Focal neurological deficits Seizures Horizontal gaze palsy Spasmodic torticollis (with the head turned towards the side of the lesion)
		Subarachnoid hemorrhage: hyperacute onset of a thunderclap headache	Rapidly worsening neurological status Meningism (neck rigidity, photophobia)
		Epidural and/or subdural hemorrhage: diffuse headache which worsens over time (the pain is worst on the side of intracranial hemorrhage)	Impaired consciousness Signs of increased intracranial pressure Ipsilateral mydriasis Possibly focal neurological deficits Epidural hemorrhage: initial loss of consciousness → symptomless lucid interval during which the patient regains consciousness → loss of consciousness for the second time Chronic subdural hemorrhage Psychomotor impairment Memory loss
	Cerebral venous sinus thrombosis	Mostly nonspecific complaints: subacute onset; a dull, diffuse headache that increases in intensity over hours/days	Sex: ♀ > ♂ Possibly focal neurological deficits Possibly signs of increased intracranial pressure Possibly impaired consciousness Risk factors: pregnancy, prothrombotic states, vasculitis, smoking, use of oral contraceptives
	Temporal arteritis	Boring, temporal headache that is synchronous with the arterial pulse	Prominent, tender temporal artery Jaw pain If temporal arteritis is associated with polymyalgia rheumatica: shoulder/pelvic pain, depression, tiredness, fever, weight loss
	Hypertensive crisis/ hypertensive emergency	Diffuse (sometimes bifrontal), pulsating headache that is exacerbated by physical activity	Syncope Possibly epistaxis Signs of end-organ damage (intracranial hemorrhage, acute heart failure, acute coronary syndrome)
	Stroke	25% of all cases present with acute headache (most commonly tension-type, less frequently migrainous or a mixed type)	Focal neurological deficits Possibly impaired consciousness
Tumors	Intracranial space-occupying lesion (e.g., brain tumors)	A dull headache that is usually bifrontal and worsens over weeks/months	Signs of increased intracranial pressure Impaired consciousness Possibly focal neurological deficits
Trauma	Traumatic brain injury	Headache of variable intensity	Possibly loss of consciousness Possibly focal neurological deficits
Other causes	Glaucoma	Severe, unilateral headache	Impaired vision Eye pain Nausea, vomiting A stony hard eyeball that is tender to touch
	Medication-overuse headache	Dull, long-lasting headache	History of analgesic overuse

Consider secondary life-threatening causes if red flags are present!

References:^{[1][2][4][5][3]}

The differential diagnoses listed here are not exhaustive.