Headache is pain in any part of the head, including the scalp, face (including the orbitotemporal area), and interior of the head. Headache is one of the most common reasons patients seek medical attention.
Pathophysiology of Headache
Headache is due to activation of pain-sensitive structures in or around the brain, skull, face, sinuses, or teeth.
Etiology of Headache
Headache may occur as a primary disorder or be secondary to another disorder.
Primary headache disorders include the following:
Trigeminal autonomic cephalgias (including cluster headache, chronic paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing Short-Lasting Unilateral Neuralgiform Headache With Conjunctival Injection and Tearing (SUNCT) Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a rare headache disorder characterized by extremely frequent attacks of unilateral head pain... read more [SUNCT])
Overall, the most common causes of headache are
Some causes of headache are common; others are important to recognize because they are dangerous, require specific treatment, or both (see table Some Characteristics of Headache Disorders by Cause Some Characteristics of Headache Disorders by Cause ).
Evaluation of Headache
Evaluation of headache focuses on
Determining whether a secondary headache is present
Checking for symptoms that suggest a serious cause
If no cause or serious symptoms are identified, evaluation focuses on diagnosing primary headache disorders.
History of present illness includes questions about the headache's characteristics:
Onset (eg, sudden, gradual)
Quality (eg, throbbing, constant, intermittent, pressure-like)
Exacerbating and remitting factors (eg, head position, time of day, sleep, light, sounds, physical activity, odors, chewing) are noted. If the patient has had previous or recurrent headaches, the previous diagnosis (if any) needs to be identified, and whether the current headache is similar or different needs to be determined. For recurrent headaches, the following are noted:
Age at onset
Frequency of episodes
Temporal pattern (including any relationship to phase of menstrual cycle)
Response to treatments (including over-the-counter treatments)
Review of systems should seek symptoms suggesting a cause, including
Fever: Infection (eg, encephalitis Encephalitis Encephalitis is inflammation of the parenchyma of the brain, resulting from direct viral invasion or occurring as a postinfectious immunologic complication caused by a hypersensitivity reaction... read more , meningitis Acute Bacterial Meningitis Acute bacterial meningitis is rapidly progressive bacterial infection of the meninges and subarachnoid space. Findings typically include headache, fever, and nuchal rigidity. Diagnosis is by... read more , sinusitis Sinusitis Sinusitis is inflammation of the paranasal sinuses due to viral, bacterial, or fungal infections or allergic reactions. Symptoms include nasal obstruction and congestion, purulent rhinorrhea... read more )
Red eye and/or visual symptoms (halos, blurring): Acute angle-closure glaucoma Angle-Closure Glaucoma Angle-closure glaucoma is glaucoma associated with a physically obstructed anterior chamber angle, which may be chronic or, rarely, acute. Symptoms of acute angle closure are severe ocular pain... read more
Visual field deficits, diplopia, or blurring vision: Ocular migraine, brain mass lesion, or idiopathic intracranial hypertension Idiopathic Intracranial Hypertension Idiopathic intracranial hypertension causes increased intracranial pressure without a mass lesion or hydrocephalus, probably by obstructing venous drainage; cerebrospinal fluid composition is... read more
Pulsatile tinnitus: Idiopathic intracranial hypertension
Preceding aura: Migraine
Focal neurologic deficit: Encephalitis, meningitis, intracerebral hemorrhage Intracerebral Hemorrhage Intracerebral hemorrhage is focal bleeding from a blood vessel in the brain parenchyma. The cause is usually hypertension. Typical symptoms include focal neurologic deficits, often with abrupt... read more , subdural hematoma Hematomas , tumor Overview of Intracranial Tumors Intracranial tumors may involve the brain or other structures (eg, cranial nerves, meninges). The tumors usually develop during early or middle adulthood but may develop at any age; they are... read more , or other mass lesion
Seizures: Encephalitis, tumor, or other mass lesion
Myalgias and/or vision changes (in people > 55 years): Giant cell arteritis Giant Cell Arteritis Giant cell arteritis involves predominantly the thoracic aorta, large arteries emerging from the aorta in the neck, and extracranial branches of the carotid arteries. Symptoms of polymyalgia... read more
Past medical history should identify risk factors for headache, including exposure to drugs, substances (particularly caffeine), and toxins (see table Disorders Causing Secondary Headache Disorders Causing Secondary Headache ); recent lumbar puncture; immunosuppressive disorders or IV drug use (risk of infection); hypertension (risk of brain hemorrhage); cancer (risk of brain metastases); and dementia, trauma, coagulopathy, or use of anticoagulants or ethanol (risk of subdural hematoma).
Family and social history should include any family history of headaches, particularly because migraine headache may be undiagnosed in family members.
To streamline data collection, clinicians can ask patients to fill out a headache questionnaire that covers most of the relevant medical history pertinent to diagnosis of headache. Patients may complete the questionnaire before their visit and bring the results with them.
Vital signs, including temperature, are measured. General appearance (eg, whether restless or calm in a dark room) is noted. A general examination, with a focus on the head and neck, and a full neurologic examination Introduction to the Neurologic Examination The neurologic examination begins with careful observation of the patient entering the examination area and continues during history taking. The patient should be assisted as little as possible... read more are done.
The scalp is examined for areas of swelling and tenderness. The ipsilateral temporal artery is palpated, and both temporomandibular joints are palpated for tenderness and crepitance while the patient opens and closes the jaw.
The eyes and periorbital area are inspected for lacrimation, flushing, and conjunctival injection. Pupillary size and light responses, extraocular movements, and visual fields are assessed. The fundi are checked for spontaneous retinal venous pulsations and papilledema Papilledema Papilledema is swelling of the optic disk due to increased intracranial pressure. Optic disk swelling resulting from causes that do not involve increased intracranial pressure (eg, malignant... read more . If patients have vision-related symptoms or eye abnormalities, visual acuity is measured. If the conjunctiva is red, the anterior chamber and cornea are examined with a slit lamp if possible, and intraocular pressure is measured.
The nares are inspected for purulence. The oropharynx is inspected for swellings, and the teeth are percussed for tenderness.
Neck is flexed to detect discomfort, stiffness, or both, indicating meningismus. The cervical spine is palpated for tenderness.
The following findings are of particular concern:
Neurologic symptoms or signs (eg, altered mental status, weakness, diplopia, papilledema, focal neurologic deficits)
Immunosuppression or cancer
Onset of headache after age 50
Thunderclap headache (severe headache that peaks within a few seconds)
Symptoms of giant cell arteritis (eg, visual disturbances, jaw claudication, fever, weight loss, temporal artery tenderness, proximal myalgias)
Systemic symptoms (eg, fever, weight loss)
Progressively worsening headache
Red eye and halos around lights
Interpretation of findings
If similar headaches recur in patients who appear well and have a normal examination, the cause is rarely ominous. Headaches that have recurred since childhood or young adulthood suggest a primary headache disorder. If headache type or pattern clearly changes in patients with a known primary headache disorder, secondary headache should be considered.
Most single symptoms of primary headache disorders other than aura are nonspecific. A combination of symptoms and signs is more characteristic (see table Some Characteristics of Headache Disorders by Cause Some Characteristics of Headache Disorders by Cause ).
Red flag findings suggest a cause (see table Matching Red Flag Findings With a Cause for Headache Matching Red Flag Findings With a Cause for Headache ).
Most patients can be diagnosed without testing. However, some serious disorders may require urgent or immediate testing. Some patients require tests as soon as possible.
MRI (and perhaps magnetic resonance angiography [MRA]) should be done as soon as possible in patients with any of the following findings:
Altered mental status
Acute focal neurologic deficit
Severe hypertension (eg, systolic > 220 mm Hg or diastolic > 120 mm Hg on consecutive readings)
If MRI is not immediately available, CT can be used.
Also, neuroimaging, usually MRI, should be done if patients have any of the following:
Focal neurologic deficit of subacute or uncertain onset
Age > 50 years
HIV infection or AIDS
Change in an established headache pattern
In addition, if meningitis Overview of Meningitis Meningitis is inflammation of the meninges and subarachnoid space. It may result from infections, other disorders, or reactions to drugs. Severity and acuity vary. Findings typically include... read more , subarachnoid hemorrhage Subarachnoid Hemorrhage (SAH) Subarachnoid hemorrhage is sudden bleeding into the subarachnoid space. The most common cause of spontaneous bleeding is a ruptured aneurysm. Symptoms include sudden, severe headache, usually... read more , encephalitis, or any cause of meningismus Encephalitis Encephalitis is inflammation of the parenchyma of the brain, resulting from direct viral invasion or occurring as a postinfectious immunologic complication caused by a hypersensitivity reaction... read more is being considered, lumbar puncture Lumbar Puncture (Spinal Tap) Lumbar puncture is used to do the following: Evaluate intracranial pressure and cerebrospinal fluid (CSF) composition (see table Cerebrospinal Fluid Abnormalities in Various Disorders) Therapeutically... read more and cerebrospinal fluid (CSF) analysis should be done, if not contraindicated by imaging results. Patients with a thunderclap headache require CSF analysis even if imaging and examination findings are normal as long as lumbar puncture is not contraindicated by imaging results. CSF analysis is also indicated if patients with headache are immunosuppressed.
Tonometry Tonometry The eye can be examined with routine equipment, including a standard ophthalmoscope; thorough examination requires special equipment and evaluation by an ophthalmologist. History includes location... read more should be done if findings suggest acute narrow-angle glaucoma Angle-Closure Glaucoma Angle-closure glaucoma is glaucoma associated with a physically obstructed anterior chamber angle, which may be chronic or, rarely, acute. Symptoms of acute angle closure are severe ocular pain... read more (eg, visual halos, nausea, corneal edema, shallow anterior chamber).
Other testing should be done within hours or days, depending on the acuity and seriousness of findings and suspected causes.
Erythrocyte sedimentation rate (ESR) should be determined if patients have visual symptoms, jaw or tongue claudication, temporal artery signs, or other findings suggesting giant cell arteritis.
CT of the paranasal sinuses is done to rule out complicated sinusitis Sinusitis Sinusitis is inflammation of the paranasal sinuses due to viral, bacterial, or fungal infections or allergic reactions. Symptoms include nasal obstruction and congestion, purulent rhinorrhea... read more if patients have a moderately severe systemic illness (eg, high fever, dehydration, prostration, tachycardia) and findings suggesting sinusitis (eg, frontal, positional headache; epistaxis; purulent rhinorrhea).
Lumbar puncture and CSF analysis are done if headache is progressive and findings suggest idiopathic intracranial hypertension Idiopathic Intracranial Hypertension Idiopathic intracranial hypertension causes increased intracranial pressure without a mass lesion or hydrocephalus, probably by obstructing venous drainage; cerebrospinal fluid composition is... read more (eg, transient obscuration of vision, diplopia, pulsatile intracranial tinnitus) or chronic meningitis Subacute and Chronic Meningitis Subacute meningitis develops over days to a few weeks. Chronic meningitis lasts ≥ 4 weeks. Possible causes include fungi, Mycobacterium tuberculosis, rickettsiae, spirochetes, Toxoplasma... read more (eg, persistent low-grade fever, cranial neuropathies, cognitive impairment, lethargy, vomiting).
Treatment of Headache
Treatment of headache is directed at the cause.
New-onset headache after age 50 should be considered a secondary disorder until proven otherwise.
Recurrent headaches that began at a young age in patients with a normal examination are usually benign.
Neuroimaging is recommended as soon as possible for patients with altered mental status, seizures, papilledema, focal neurologic deficits, or thunderclap headache.
CSF analysis is required for patients with meningismus and usually for immunosuppressed patients after neuroimaging.
Patients with thunderclap headache require CSF analysis even if neuroimaging and examination findings are normal as long as lumbar puncture is not contraindicated by imaging results.