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.
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 :
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:
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.
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.
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:
Important additional questions to ask are:
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:
SNOOP: Red flags for dangerous underlying conditions
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:
Conversely, if patients have high-risk features or a history and physical not compatible with primary headache, the etiology of secondary headache must be investigated. As is often the case in clinical medicine, pattern recognition is useful. The following are several of the most important critical diagnoses of secondary headaches to consider and their key clinical features:
Evaluation of headache in the emergency department should begin with a thorough history and physical exam when permitted. Most headaches can be attributed to primary benign headache subtypes deduced through the primary survey; however, sometimes, further evaluation will be warranted. There is no single algorithm or clinical decision rule that applies to all emergency department patients with headache. Thus, determining necessary evaluation requires a sophisticated clinical approach that is evidence-based and hypothesis-driven.
Routine laboratory testing is typically not helpful in headache diagnosis. However, if a life-threatening cause of headache is suspected, certain tests may be useful. Female patients with headaches and elevated blood pressure should be screened for pregnancy. Patients with headache and altered mental status or focal neurologic deficits require a serum glucose level. A carboxyhemoglobin level should be obtained if there is suspicion of carbon monoxide poisoning.
If there is suspicion for giant cell arteritis (GCA), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) should be obtained, however, if normal and suspicion remains high patients should be treated for GCA pending temporal artery biopsy results.
In patients with suspected cerebral venous thrombosis (CVT), coagulation studies may be abnormal. D-dimer may be useful to exclude CVT in low-risk patients (defined as patients with a normal neurologic exam, normal head CT, and absence of risk factors such as current or recent pregnancy), but high-risk patients should proceed to MRV regardless of level.
Abnormalities in white blood cell (WBC) levels are associated with infective or inflammatory etiologies but are non-specific.
The 2019 ACEP clinical policy on headache recommends neuro-imaging in patients with headache and any new neurologic deficits, new and sudden-onset severe headache, HIV-positive patients with a new type of headache, and patients greater than 50 with a new headache. This policy is helpful but does not include every scenario where imaging is warranted. Generally, the positive predictive value of pathology on neuroimaging increases with :
Typically in the subset of patients suspected of an emergent headache, non-contrast head CT is the screening test of choice. However, alternative and/or additional imaging choice should be directed toward the specific emergent diagnosis in question. For example, cerebral CT angiography (CTA) can be useful in identifying nontraumatic subarachnoid hemorrhage, arterial dissections, dural sinus thrombosis, and posterior circulation pathologies. Although dural sinus thrombosis may be seen on non-contrast CT and CTA, the test of choice is MRI and MR venography (MRV), or CT with CT venography if MRI is unavailable.
Lumbar puncture (LP) and cerebrospinal fluid studies should be considered in some patients with headache. Indications include fever with altered mental status, meningeal signs, focal neurological deficits, and history of HIV or another immunocompromised state. Additionally, LP is indicated in a patient whose history and physical exam is suspicious for idiopathic intracranial hypertension, as elevated opening pressure would be diagnostic. Of note, CT is estimated to be negative in up to 5% of patients with subarachnoid hemorrhage; thus, CSF examination for red blood cells or xanthochromia can be useful if the index of suspicion for hemorrhage is high. More recent studies have suggested that in patients who arrive within 6 hours of headache onset, CT (without LP) is sufficient to rule out subarachnoid hemorrhage. In the setting of suspected increased intracranial pressure, LP should not be performed before CT imaging to rule out asymmetric space-occupying lesions, as reduction of pressure from LP can result in fatal herniation. LP should also not delay antibiotics if suspicious of an infectious process.
Often clinicians will pursue these modalities to avoid missing potentially fatal or debilitating conditions. It is not uncommon for these exams to reveal no abnormalities. Clinicians should use these modalities as tools, along with clinical judgment, to decide if the patient should be further observed and examined or if the next step is to follow up with primary care for possible primary headache syndromes.
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:
Opiates should be avoided, as they increase ED visit frequency, decrease the efficacy of other medications, and carry a high addiction burden. If a patient specifically requests opiates, abuse and dependence may be a consideration. These patients should have access to counseling and interventions aimed to address opiate abuse and addiction.
Another treatment modality increasingly utilized in the ED is the administration of a noninvasive intranasal sphenopalatine ganglion nerve block, in which topical local anesthetic is applied intranasally via a long cotton-tipped applicator. In a 2015 trial by Schaffer et al., it was found that patients with an acute headache not attributable to secondary pathology reported at least a 50% reduction in headache severity with the administration of 0.3 mL 0.5% bupivacaine solution compared with placebo. In another trial by Binfalah et al., it was found that 70.9% of patients receiving 2 mL 2% lidocaine solution reported being headache-free after 15 minutes. The emergence of the sphenopalatine nerve block method of analgesia is still somewhat new and controversial, yet appears to be a relatively safe and effective treatment for primary headache conditions as well as facial pain syndromes such as trigeminal neuralgia.
Treatment of a secondary headache depends on identifying and treating the underlying pathology.
The differential diagnosis for headache is broad. Additional conditions that can be accompanied by headache not yet discussed include:
The prognosis of primary headache is variable and depends on the sub-type. Primary headaches are often recurrent and thus create a heavy medical burden on both emergency medicine and primary care. Prognosis is favorable, as primary headaches do not cause death or permanent disability. Recurrent headaches, however, may be distressing enough to cause temporary disability for some sufferers. A specialist should medically manage such headaches. Remission from chronic headache is possible, and predictors often include withdrawal from analgesic medications, compliance with preventative medications, physical exercise, and stress reduction.
The prognosis of secondary headaches depends on the underlying pathology. Many causes of secondary headaches are chronic conditions that demand ongoing medical management for the reduction of symptoms. Some causes of secondary headaches are severely debilitating or even fatal. Medical management in these cases should be aimed at rapid resuscitation, minimizing systemic effects, and maximizing patient comfort to achieve the best outcomes.
Complications of primary headaches are most often secondary to the temporary loss of normal functionality that they pose, and can include loss of workdays and productivity. One complication of treating chronic primary headaches is medication overuse headache, also known as a rebound headache. This phenomenon occurs when tolerance develops to headache analgesia. In this instance, headache is no longer responsive to treatment and worsens precipitously when the analgesic is abruptly stopped.
Complications of secondary headache range from mild, temporary disability, and discomfort to severe neurologic disability and even death. It is critical for a physician to consider secondary causes of headache through a comprehensive primary and secondary survey to ensure that the underlying pathology of a patient’s headache is correctly managed, minimizing complications of late treatment.
For primary headaches, patients should be educated about the benign nature of their condition. Knowing that despite the discomfort, their headache poses no long term sequelae is often enough to mitigate some of the debilitating effects of the headache. Patients should also be urged to follow up with a specialist if they suffer from recurrent headaches. Such follow up can offer appropriate preventative or abortive medication options. Further, patients should be encouraged to keep track of their headaches and be mindful of potential triggers, as avoidance of those triggers can ultimately reduce headache burden and improve the quality of life. For some patients, simple lifestyle interventions such as getting adequate sleep and avoiding excessive caffeine may improve chronic headaches. Patients should also be educated on rebound medication overuse headaches, how they occur, how to avoid them, and how to otherwise manage their headache burden.
Patients with secondary headaches should be educated about the underlying pathology and how to optimize management so as to minimize their symptom burden. Further, if a headache is secondary to medical intervention or trauma, patients should know which activities to avoid and for how long, as well as possible "red flags" which should prompt them to seek immediate medical care.
Headache is a common chief complaint in the emergency room, and though the vast majority of cases will require only analgesia and reassurance, the emergency medical team must always be vigilant about identifying the more serious cases. Managing these critical secondary causes of headache requires an interdisciplinary team of doctors, nurses, and ancillary staff. Professionals involved will vary depending on the underlying pathology, but most commonly, medical teams will include emergency physicians, neurologists, radiologists, pharmacists, critical care specialists, and neurosurgeons. Communication between nurses and physicians is critical; in order to monitor response to treatment and immediately note any clinical deterioration. Often, the management of these patients does not end in the emergency department. Effective communication during the handoff between emergency and inpatient teams is essential. Planning and coordination between teams of professionals involved in the care of the patient are important for favorable healthcare outcomes. [Level 1]
This research was supported in part by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities.
|||Burch R,Rizzoli P,Loder E, The Prevalence and Impact of Migraine and Severe Headache in the United States: Figures and Trends From Government Health Studies. Headache. 2018 Apr [PubMed PMID: 29527677]|
|||Tabatabai RR,Swadron SP, Headache in the Emergency Department: Avoiding Misdiagnosis of Dangerous Secondary Causes. Emergency medicine clinics of North America. 2016 Nov [PubMed PMID: 27741984]|
|||Potter R,Probyn K,Bernstein C,Pincus T,Underwood M,Matharu M, Diagnostic and classification tools for chronic headache disorders: A systematic review. Cephalalgia : an international journal of headache. 2019 May [PubMed PMID: 30335472]|
|||Headache Classification Committee of the International Headache Society (IHS) The International Classification of Headache Disorders, 3rd edition. Cephalalgia : an international journal of headache. 2018 Jan [PubMed PMID: 29368949]|
|||Robbins MS,Lipton RB, The epidemiology of primary headache disorders. Seminars in neurology. 2010 Apr [PubMed PMID: 20352581]|
|||Rasmussen BK,Jensen R,Schroll M,Olesen J, Epidemiology of headache in a general population--a prevalence study. Journal of clinical epidemiology. 1991 [PubMed PMID: 1941010]|
|||[PubMed PMID: 18339350]|
|||[PubMed PMID: 28329901]|
|||[PubMed PMID: 31543134]|
|||[PubMed PMID: 11782746]|
|||[PubMed PMID: 23939446]|
|||[PubMed PMID: 17406159]|
|||[PubMed PMID: 30879843]|
|||[PubMed PMID: 27306497]|
|||[PubMed PMID: 30743289]|
|||[PubMed PMID: 15858188]|
|||[PubMed PMID: 20530782]|
|||[PubMed PMID: 31741184]|
|||[PubMed PMID: 24847166]|
|||[PubMed PMID: 26226865]|
|||[PubMed PMID: 26422648]|
|||[PubMed PMID: 12893694]|
|||[PubMed PMID: 16884778]|
|||[PubMed PMID: 22119103]|
|||[PubMed PMID: 26215857]|
|||[PubMed PMID: 29784833]|
|||[PubMed PMID: 21293023]|
|||[PubMed PMID: 25862794]|
|||[PubMed PMID: 29395690]|
|||[PubMed PMID: 26595867]|
|||[PubMed PMID: 22404708]|
|||[PubMed PMID: 17942818]|
|||[PubMed PMID: 30449536]|
|||[PubMed PMID: 28967120]|
|||[PubMed PMID: 25577713]|
|||[PubMed PMID: 29862074]|
|||[PubMed PMID: 25952071]|
|||[PubMed PMID: 28886861]|
|||[PubMed PMID: 31849829]|
|||[PubMed PMID: 30906963]|
|||[PubMed PMID: 30637489]|
|||[PubMed PMID: 27820426]|