ACUTE HEADACHE

Leeran Baraness; Annalee M. Baker

Introduction

Headache, or pain located in any part of the head, is a nearly universal ailment. Headaches comprise
3% of emergency department chief complaints. While most headaches are benign (96%), recognition
of less common, emergent causes of headache is critical, as a timely intervention may be life-
saving. The primary role of the emergency physician (EP) is to carefully analyze specific aspects of the
history and physical exam to determine which patients are at risk for serious underlying pathology.
The emergency physician must decide which patients require immediate further testing, such as
laboratory studies and imaging, to confirm the diagnosis and direct management. In addition to
diagnosing and managing life-threatening causes of headache, the EP must be well versed in the
treatment of common primary headache disorders, as proper management of the natural course of the
disease may improve patient outcomes.

Etiology

Headaches are broadly classified as primary or secondary. Primary headaches are those with no
identifiable underlying cause. Secondary headaches are the result of other underlying pathology.

The International Classification of Headache Disorders (ICHD-III) classifies headaches as either:

 Primary headache, including tension, migraine, and cluster

 Secondary headache, including potentially life-threatening etiologies such as traumatic brain

injury and vascular disorders

 Cranial neuropathies, such as trigeminal neuralgia

Headache can be a symptom of many underlying pathologies, some of which can lead to severe
disability and mortality. The emergency clinician should be especially familiar with the following
conditions:

 Hypertensive emergencies

 Idiopathic intracranial hypertension

 Carotid or vertebrobasilar dissection

 Space occupying lesions (tumors, abscesses, cysts)

 Acute hydrocephalus

 Dural sinus thrombosis

 Intracranial hemorrhage
  Giant cell (temporal) arteritis

 Cerebrovascular accident or stroke

 Meningitis and encephalitis

 Carbon monoxide poisoning

 Toxin exposure or withdrawal

 Acute angle-closure glaucoma

 Medication overuse headache

Epidemiology

The burden of headache is considered to be underestimated and undertreated by the medical

community. Unlike most chronic diseases, much of the morbidity associated with headache disorders
is focused in otherwise young, healthy people. The prevalence of headache tends to peak between the
ages of 25 to 40 and decreases with age in both sexes. In the United States, the prevalence of having
experienced a headache of any type in one's lifetime is estimated to be 96%. Women tend to suffer
more than men from active headache disorders. For example, the prevalence of severe headaches or
migraines is 20.7% in women and 9.7% in men. It remains unclear whether regional differences in
headache prevalence exist. Differences in international methods of data collection, diagnostic criteria,
and cultural characterization of headaches can impact this data.

Pathophysiology

The brain parenchyma does not have nociceptors, and thus, headache is typically the result of pain
originating in surrounding structures, such as blood vessels, meninges, muscle fibers, facial structures,
and cranial or spinal nerves. Stretching, dilatation, constriction, or any nociceptor stimulation within
these structures can result in the perception of headache. However, primary headache
pathophysiology is not fully understood. There have been many studies attempting to correlate
certain anatomical and physiological derangements to specific types of primary headaches, but it is
unlikely that a single mechanism underlies all primary headaches. The pathophysiology of secondary
headache depends on the underlying process.

History and Physical

Very often in patients with headache, the diagnosis can be established by careful history taking and
physical examination. Primary headaches are not life-threatening and do not require imaging in the
emergency department. Many types of secondary headache (e.g., TMJ, uncomplicated otitis media,
hangover headache) are similarly benign and require little or no additional workup beyond a
thorough history and physical. Certain more serious etiologies of secondary headache, though less
common, must be considered before establishing a diagnosis of primary headache.

History should be geared toward obtaining a detailed account of the current headache, a full review
of systems, and a description of any prior headache disorder or headache history. Specific questions
relating to any possible life-threatening causes of secondary headache should be asked, as the answers,
along with any examination findings, will direct additional testing or emergent therapy.

As with any chief complaint of pain, the history should begin with the following questions:

 Where is the pain located?

 When did the pain begin?

 What was the patient doing when the pain began?

 How has the pain progressed? Is it improving, worsening, or constant?

 What is the quality of the pain?

 What is the severity of the pain?

 Does anything make the pain better or worse?

 Does the pain radiate?

 Has the patient experienced pain like this in the past?

Important additional questions to ask are:

 What is the patient's medical history?

 Does the patient take new medications, or have they recently made changes to their
medications?

 Does the patient take "blood thinners"?

 Is this the worst headache the patient has ever experienced?

 Was the pain maximal at the onset?

 Has the patient had any difficulty moving or speaking normally?

 Did the patient have nausea or vomiting?

 Does the patient have a fever?

 Does the patient have any changes in vision or hearing?

 Does the patient have eye pain?

 Does the patient have any neck or facial pain?

 Did the patient have a seizure?

 Does the patient have dizziness?

 Does the patient have any sensitivity to light?

 Does the patient feel generally weak?

  Is there a weakness in a specific area of their body?

 Has the patient traveled recently?

 Has the patient been around sick contacts?

 Is the patient less than 6 weeks postpartum?

 Does the patient have a history of immunosuppression or take immunosuppressive

medication?

A thorough physical examination is important in all patients presenting with headache. Although the
neurologic exam is the most obvious imperative, it is also crucial to perform a complete HEENT exam,
which may uncover findings suggestive of either benign (sinusitis, otitis, odontogenic headache) or
serious conditions (e.g., papilledema suggesting intracranial pressure, temporal artery tenderness
suggesting giant cell arteritis).

Certain clinical features suggest that a patient is very unlikely to have a serious etiology of
headaches. Conversely, screening mnemonics such as SNOOP (see below) can be useful to elicit
clinical clues of life-threatening diagnoses. If a patient has all of the low-risk features and none of the
red flags, further history and exam can be directed toward determining the type of primary headache,
or the benign secondary cause. If high-risk features are present additional workup is mandated, and
patients typically require emergent neurological imaging.

Low-risk features include:

 Age under 50 years

 Features typical of primary headaches

 History of similar headache

 Normal neurologic exam

 No change in the usual headache pattern

 No high-risk comorbidities

 No new or concerning findings on history or physical

SNOOP: Red flags for dangerous underlying conditions

 S: Systemic illness (fever, cancer, pregnancy, HIV)

 N: Neurologic signs or symptoms (confusion, focal neurologic signs, seizures, papilledema)

 O: Onset is new or sudden (especially if age over 50)

 O: Other associated features (head trauma, drugs or toxins, headache awakens from sleep or
worse with Valsalva, precipitated by coughing or exertion)

 P: Previous headache history with progression or change in characteristics

History and physical are usually sufficient to diagnose primary headaches, provided no high-risk
features are present. For primary headaches, physicians must be able to differentiate the type of
primary headache to initiate proper therapy.

Clinical features of primary headache subtypes:

 Migraine headache

o Typically unilateral in adults, bilateral in children

o Gradual onset, crescendo pattern, pulsating, moderate or severe, aggravated by

routine activity

o Duration 4 to 72 hours

o Patient most comfortable resting in a dark, quiet room

o May have associated nausea, vomiting, photophobia, phonophobia, aura (most often
visual)

 Tension headache

o Typically, bilateral

o Pressure or tightness, waxing and waning intensity

o Duration 30 minutes to 7 days

o The patient may be active or desirous of rest

o Usually no associated symptoms

 Cluster headache

o Always unilateral, usually beginning near the temple or eye

o Pain begins quickly, reaching maximal intensity in minutes, quality is deep, constant,
excruciating or explosive

o Duration 15 minutes to 3 hours

o Patient remains active

o Associated symptoms include ipsilateral lacrimation and redness to the eye, nasal
congestion or rhinorrhea, pallor, diaphoresis, horner syndrome, restlessness

Treatment / Management

Treatment of primary headache in the emergency department should be focused on reducing

symptoms and providing supportive care. Often, primary headaches are recurrent, and follow up
with a neurologist or primary care physician should be recommended for preventive and abortive
management options. The goal of medical management of headache centers on achieving fast and
long-lasting analgesia with little to no side effects. Headaches are frequently associated with nausea
and vomiting, so medications should be administered parenterally when possible. Treatment should
also include managing patient expectations. Headache recurrence is common, and patients
should understand both what to do for a headache that recurs at home, and when to return to the
emergency department.

Medication options with favorable outcomes include:

 Fluid rehydration

o IV fluids themselves have not been shown to provide pain relief; however, rehydration
is important in patients with nausea and vomiting who may not be tolerating oral
intake.

 Antidopaminergic agents such as prochlorperazine, chlorpromazine, promethazine, and

metoclopramide

o These medications provide both analgesic and antiemetic effects. Extrapyramidal

symptoms are a possible side effect of these medications; this can be treated
with diphenhydramine, which is often given contemporaneously to metoclopramide.

 Acetaminophen

o This medication has been shown to provide good short term relief, but recurrence rates
remain high.

 NSAIDs such as ibuprofen, ketorolac, naproxen, and diclofenac

o Excellent analgesic effect. Generally well-tolerated, but caution should be used in

patients at risk of bleeding. These agents inhibit cyclooxygenase, thus reducing
platelet function, which could exacerbate bleeding. Side effects of these medications
include GI irritation and nephrotoxicity when used over time.

 Triptans such as sumatriptan

o These medications have been shown to provide good long term relief and are often
used to prevent and abort migraine headaches, but their side effect profile causes them
to be prescribed primarily in the outpatient setting where follow-up is more easily
facilitated. Side effects of triptans are primarily vascular, including chest pain,
shortness of breath, and flushing. Triptans have poor bioavailability when
administered enterally; hence IV or subcutaneous administration is preferred.

 Corticosteroids such as dexamethasone

o Steroids have been shown to decrease headache recurrence, in particular for

migraines, which have lasted greater than 72 hours. Steroids may also give some
adjunctive analgesia when given with metoclopramide, though they are inadequate
when given alone.