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CHAPTER 165: Headache 1107 Headache Alex Koyfman Brit Long INTRODUCTION AND EPIDEMIOLOGY Headache is the fourth most common symptom presenting to the ED in the United States, accounting for close to 3% of total ED visits.1 Overall, headaches affect people across all ethnic, geographic, and economic levels, with an estimated global prevalence of 47% in adults. In the ED, the approach to headache focuses on identifying patients at risk for rapid deterioration, morbidity, and mortality; rapidly identifying high-risk headache syndromes; and providing appropriate headache therapy. PATHOPHYSIOLOGY The brain parenchyma has no pain sensors. 3 Early theories postulating vasoconstriction and rebound vasodilatation as the cause of migraine have been refuted. 4 Numerous physiologic mechanisms play a role in the development of the various clinical headache syndromes. For example, occipital nerve irritation may lead to the development of occipital neu ralgia. 5 Similarly, headaches associated with disturbances in intracranial pressure (high and low) are related to compression of, or traction on, pressure-sensitive structures in the meninges. 6 The pathophysiologic mechanisms of other headache syndromes, such as migraine headaches, cluster headaches, and toxic and metabolic headaches, are less clear. Discussion of these mechanisms is beyond the scope of this chapter. CLINICAL FEATURES Although headaches are typically classified as primary headaches when there is no underlying cause (such as migraine, tension, or cluster headaches) and secondary headaches if associated with an underlying cause (such as tumor, meningitis, or subarachnoid hemorrhage), this distinc tion is not clinically useful in the ED setting. Rather, the emergency physician should focus on evaluating for and ruling out secondary causes of headache. Most patients with headache have conditions that are painful but benign in etiology. Identifying those at high risk for a secondary headache is the first step in management ( Table 165-1). A high-risk cause for headache accounts for only 4% of all headaches but 10% to 14% of acute-onset (“thunderclap”) headaches. 7,8 Improvement of the patient’s pain with treatment does not predict benign cause of headache. HISTORY Features associated with high-risk headaches are as follows: Patient Age Patients >50 years of age, with a new or worsening head ache, represent a high-risk group. 9 The incidence of migraine, cluster, and tension headaches decreases with age, raising the likelihood of ominous pathology for older patients.10 Close to 15% of patients over age 65 will have a dangerous secondary headache on neuroimaging,11 and those over 50 have four times the rate of pathology.7 Onset of Symptoms The abrupt onset of severe headache, or “thunderclap” headache, requires immediate and thorough evaluation. 12 A thunderclap headache is defined by pain that reaches 7 out of 10 in less than 1 minute. 13 Thunderclap headache associated with intracerebral aneurysmal leak (“sentinel hemorrhage” or “herald bleed”) may precede catastrophic aneurysmal rupture by days to weeks. Associated symp toms may include neck stiffness, nausea, vomiting, loss of conscious ness, neurologic deficit, or altered mentation. 14 Onset of thunderclap headache during periods of exertion raises suspicion for subarachnoid hemorrhage or arterial dissection of the carotid or vertebrobasilar circulation.
ys to weeks. Associated symp toms may include neck stiffness, nausea, vomiting, loss of conscious ness, neurologic deficit, or altered mentation. 14 Onset of thunderclap headache during periods of exertion raises suspicion for subarachnoid hemorrhage or arterial dissection of the carotid or vertebrobasilar circulation. A headache with seizure, altered mental status, visual dis turbance, or focal neurologic deficit may be due to posterior reversible encephalopathy syndrome 15 or reversible cerebral vasoconstriction syndrome.16 Headaches associated with the Valsalva maneuver may herald an intracranial abnormality. 17 Rarely, spontaneous intracranial hypotension and acute hydrocephalus associated with third ventricular colloid cyst may present with thunderclap headache. 18 Other causes for thunderclap headache are listed in Table 165-2. Headache Quality A change in pattern, frequency, quality, or intensity of a preexisting headache syndrome needs the same evaluation as a newonset headache syndrome. Fever Fever raises concern for CNS infection, such as meningitis, encephalitis, or brain abscess. However, the absence of fever does not exclude a CNS infection, especially in patients at the extremes of age and with immunocompromised states, such as human immunodeficiency virus. Headaches in patients with human immunodeficiency virus and CD4 count less than 200 cells/μL have a higher risk of intracranial pathology. 19,20 CHAPTER TABLE 165-1 High-Risk Features for Headache: Clinical “Red Flags” Onset Sudden Trauma Exertion Symptoms Altered mental status Seizure Fever Neurologic symptoms Visual changes Medications Anticoagulants/antiplatelets Recent antibiotic use Immunosuppressants Past history No prior headache Change in headache quality, or progressive headache worsening over weeks/months Associated conditions Pregnancy or postpregnancy status Systemic lupus erythematosus Behçet’s disease Vasculitis Sarcoidosis Cancer Physical examination Altered mental status Fever Neck stiffness Papilledema Focal neurologic signs TABLE 165-2 Causes of Thunderclap Headache Hemorrhage Intracranial hemorrhage “Sentinel” aneurysmal hemorrhage Spontaneous intracerebral hemorrhage Vascular Carotid or vertebrobasilar dissection Reversible cerebral vasoconstriction syndrome (RCVS) Cerebral venous thrombosis Posterior reversible encephalopathy syndrome (PRES) Other causes Coital headache Valsalva-associated headache Spontaneous intracranial hypotension Acute hydrocephalus (e.g., colloid cyst obstructing third ventricle) Pituitary apoplexy Acute angle-closure glaucoma Tintinalli_Sec14_p1101-1186.indd 1107 8/2/19 12:08 PM
is Posterior reversible encephalopathy syndrome (PRES) Other causes Coital headache Valsalva-associated headache Spontaneous intracranial hypotension Acute hydrocephalus (e.g., colloid cyst obstructing third ventricle) Pituitary apoplexy Acute angle-closure glaucoma Tintinalli_Sec14_p1101-1186.indd 1107 8/2/19 12:08 PM 1108 SECTION 14: Neurology TABLE 165-3 Clinical Features Suggestive of Migraine Prior history of migraine Younger age Multiple prior episodes Aura and prodrome Familiar triggers Family history History of motion sickness Moderate/severe intensity Unilateral Throbbing Nausea/vomiting Photophobia/phonophobia Lasts hours TABLE 165-4 Clinical Features Suggestive of Cluster Headache At least 5 attacks that meet the following criteria: • Severe • Unilateral • Lasts 15–180 min (untreated) • Circadian/circannual pattern Associated ipsilateral symptoms (at least one): • Lacrimation • Conjunctival injection • Nasal congestion or rhinorrhea • Ptosis and/or miosis • Edema of the eyelid and/or face • Sweating of the forehead and/or face Past Medical History The past medical history is essential in deter mining risk of secondary etiology for headache. A history of immu nocompromised state (including human immunodeficiency virus, vasculitis, diabetes, among others) may prompt need for further evalu ation. History of malignancy, trauma, current pregnancy, and recent pregnancy are suggestive of a secondary cause of headache. Medication History Inquire about over-the-counter medications, anticoagulants, antiplatelet agents, chronic steroids, immunomodula tory agents, or antibiotics (prescribed or not) to identify patients at high risk for infection (e.g., eculizumab and its elevated risk for meningococcal infection). Chronic use of analgesic and anti-inflammatory agents may result in rebound or withdrawal headaches . Medication overuse is defined as use >10 times a month and is notable for ergots, triptans, and opioids. 17 Anticoagulants and antiplatelet agents increase the risk for hemorrhage, both spontaneous and traumatic. 21 The recent use of antibiotics may present with a falsely reassuring clinical appearance due to partial treatment of a potentially dangerous CNS infection. Prior Headache History A prior history suggestive of migraine, ten sion, or cluster-type headaches and response to specific therapy may obviate the need for extensive ED evaluation (Tables 165-3 and 165-4). Substance Use History Use of adrenergic agents such as cocaine, amphetamine, or derivative compounds such as methamphetamine increases risk of intracranial hemorrhage or the less common entity of reversible cerebral vasoconstriction syndrome. 22 Patients with a history of alcohol abuse are at increased risk of intracranial bleeding due to falls, interpersonal violence, and the potential for liver dysfunction associated with prolonged coagulation times and thrombocytopenia. Family History Known aneurysm or sudden death in first-degree relatives raises the suspicion for intracranial aneurysm. 23 The inci dence of aneurysm in patients with a family history is three to five times higher than in those without a family history. A personal or family history of autosomal dominant polycystic kidney disease also increases the risk for intracranial aneurysm. In patients with autoso mal dominant polycystic kidney disease, aneurysmal rupture is more likely to occur at a younger age. The presence of migraine in a firstdegree relative is associated with a two- to fourfold increased risk of developing migraine. PHYSICAL EXAMINATION Vital Signs Headache is a common symptom associated with fever, as headache is seen in up to 60% of patients with upper respiratory tract infection symptoms.
ounger age. The presence of migraine in a firstdegree relative is associated with a two- to fourfold increased risk of developing migraine. PHYSICAL EXAMINATION Vital Signs Headache is a common symptom associated with fever, as headache is seen in up to 60% of patients with upper respiratory tract infection symptoms. 7,25 The persistence of headache in the presence of a normalized temperature suggests consideration for further evaluation of a possible CNS infection. The presence of fever in association with neck stiffness and altered mental status represents the classic triad of menin gitis. Close to 95% of patients with bacterial meningitis present with at least two of the four findings (classic triad plus headache). Severe hypertension can be associated with headache and the devel opment of acute changes in mental status and neurologic function. Consider posterior reversible encephalopathy syndrome 27 and hypertensive emergency in such patients (see “Posterior Reversible Encephalopathy Syndrome” section). Examination of the Head and Neck Meningismus is an important clinical clue to the presence of infection or hemorrhage. 26 Examine the ears, nose, and throat to identify otitis media and sinusitis, both of which may cause headache and contribute to the extension of infection to the CNS. Palpate for scalp tenderness and tenderness over the temporal arteries to assess for possible temporal arteritis. Examination of the Eye Headache can occur with acute angle-closure glaucoma, scleritis, and endophthalmitis. Visual complaints require consideration of secondary etiology. Consider acute angle-closure glaucoma even when there is no focal ocular complaint, as the pain can be so severe the patient may fail to localize pain to the eye. Measure intraocular pressure to exclude glaucoma. Check visual acuity and visual fields and examine the pupils and eyelids, checking for signs of Horner’s syndrome. Funduscopic Examination Papilledema can be seen in the presence of raised intracranial pressure. However, there is typically a delay in the onset of papilledema once intracranial pressure begins to elevate, and papilledema can persist once intracranial pressure returns to normal. The ability to recognize papilledema by routine direct ophthalmoscopy alone (particularly with nondilated pupils) is limited, but a panoptic ophthalmoscope provides a more reliable view of the retina. 29 Bedside US of the optic nerve sheath can also assess for papilledema. 30,31 The presence of papilledema requires CT imaging before lumbar puncture.32 Neurologic Examination A baseline neurologic assessment includes the following: mental status assessment; cranial nerve examination, including pupillary examination (for asymmetry or ptosis, which may suggest third nerve compression by posterior communicating artery aneurysms); assessment for other cranial neuropathies (which may raise suspicion for carcinomatous meningitis); motor examination to detect extremity weakness (particularly subtle weakness with pronator drift); reflex examination for subtle asymmetry or a Babinski reflex; and gait and coordination testing (which may be impaired in cerebellar lesions). Any neurologic deficit, including altered mental status, possesses the highest predictive value for CNS pathology. DIAGNOSIS There are many causes of headache, each of which is diagnosed and managed differently. LABORATORY TESTING Routine blood testing is of limited utility in the diagnosis of acute headache and should be guided by the patient’s age, history, relevant comorbidities, and medication history. The laboratory evaluation of patients with high-risk headaches may include basic metabolic profile, CBC, coagulation panel, erythrocyte sedimentation rate, C-reactive protein, and blood cultures for possible infection.
e and should be guided by the patient’s age, history, relevant comorbidities, and medication history. The laboratory evaluation of patients with high-risk headaches may include basic metabolic profile, CBC, coagulation panel, erythrocyte sedimentation rate, C-reactive protein, and blood cultures for possible infection. IMAGING Selecting an appropriate imaging study depends on the history, physi cal examination findings, and differential diagnosis of headache, 34-36 as well as the resources available to the emergency provider. Table 165-5 summarizes some of the American College of Radiology and American College of Emergency Physicians recommendations for appropri ate imaging. When MRI is immediately unavailable and diagnostic Tintinalli_Sec14_p1101-1186.indd 1108 8/2/19 12:08 PM
6 as well as the resources available to the emergency provider. Table 165-5 summarizes some of the American College of Radiology and American College of Emergency Physicians recommendations for appropri ate imaging. When MRI is immediately unavailable and diagnostic Tintinalli_Sec14_p1101-1186.indd 1108 8/2/19 12:08 PM CHAPTER 165: Headache 1109 uncertainty regarding the possibility of an underlying lesion prevails, further imaging may be necessary, the timing of which will depend on the clinical circumstances and likelihood of the patient being able to follow up in a reliable fashion. If the patient presents with a typical history of headache that responds to typical measures and a normal neurologic examination, avoid neuroimaging to reduce radiation exposure. When appropriate, a noncontrast head CT is the fastest and most appropriate initial imaging study, as well as the most sensitive for detecting acute intracranial hemorrhage. 36,37 Gadolinium-based magnetic resonance contrast agents are contrain dicated for patients with renal insufficiency due to risk of nephrogenic systemic fibrosis, and intravenous contrast for CT should be carefully considered in patients with renal insufficiency, although literature sug gests no association of contrast with renal injury. 38,39 Gadolinium is relatively contraindicated in pregnancy and breastfeeding women. MRI can be limited by claustrophobia. A discussion with the radiologist and/ or radiology technical staff can clarify the safety of MRI in patients with devices or foreign bodies. Magnetic resonance angiography is useful in detecting arterial disease (stenosis, congenital anomalies, dissection, CNS vasculitis) and should be considered in any case where there may be arterial pathology underlying the patient’s symptoms. Discuss concerns for dissection with the radiologist to determine the most appropriate MRI method. If MRI is unavailable or not clinically feasible, consult radiology regarding other appropriate imaging modalities. LUMBAR PUNCTURE After the clinical assessment, blood work, and imaging, the next step is to determine whether to perform a lumbar puncture (LP) and, if so, the timing of LP . LP can serve as both a diagnostic tool (as in men ingitis, subarachnoid hemorrhage, intracranial hypotension, carcino matous meningitis) and therapeutic tool (as in idiopathic intracranial hypertension). Ideally, perform the LP with the patient in the lateral decubitus position to allow for the accurate measurement of opening pressure. Seated LP does not allow for accurate assessment of opening pressure. Opening pressure provides critical information about the patient’s intracranial pressure and should be considered a routine procedure when perform ing LP . The possibility of herniation in association with LP is a frequent concern of emergency providers. There is no randomized controlled trial assessing the question of when it is safe to perform an LP . The cumulative evidence suggests that in patients with normal sensorium, no focal neurologic deficit, and without a history of immunosup pression, it is safe to proceed with LP without imaging prior to the procedure. 40,41 In the evaluation of patients with suspected acute bacterial menin gitis, clinical signs of “impending” herniation are the best predictors of when to delay an LP because of the risk of precipitating herniation. Risk of an abnormal CT scan is elevated in patients with any of the following clinical features: a deteriorating or altered level of consciousness (particularly a Glasgow Coma Scale score of ≤11), brainstem signs (including pupillary changes, posturing, or irregular respirations), focal neurologic deficit, history of recent seizure, history of a preexisting neurologic disorder, or history of immunocompromised state.
deteriorating or altered level of consciousness (particularly a Glasgow Coma Scale score of ≤11), brainstem signs (including pupillary changes, posturing, or irregular respirations), focal neurologic deficit, history of recent seizure, history of a preexisting neurologic disorder, or history of immunocompromised state. In patients with these clinical features, imaging prior to LP is appropriate, but never delay antibiotic administration while imaging is obtained. In patients without such findings, it is usually safe to perform LP without obtaining a CT scan in cases of suspected bacterial meningitis. DISPOSITION AND FOLLOW-UP Most patients with headache can be treated and released from the ED with an appropriate follow-up plan. Identification of potential barriers to follow-up is an important step in ensuring that proper follow-up will be available to all patients, particularly for patients with limited resources or other barriers to accessing medical care. For some patients, inpatient care or observation may be warranted until symptoms improve or until testing is completed. A follow-up plan is important for patients with high-risk conditions, such as temporal arteritis or idiopathic intracranial hypertension. Follow-up is similarly important for patients with chronic headaches, given the potential for substance abuse, overutilization of resources, and repeated unnecessary imaging with potentially harmful radiation. SPECIFIC CAUSES OF HEADACHE MENINGITIS/ENCEPHALITIS Consider meningitis and encephalitis in patients with headache and the classic triad of fever, altered mentation, and neck stiffness. 26 Meningitis is due to the meningeal infection and inflammation, while encephalitis results from infection and inflammation of the underlying neural tissue. The combination of headache, fever, and neck stiffness is present in 44% of cases of meningitis, although 99% of patients will have at least one of these symptoms. 26 The source of infection in meningitis can be viral, bacterial, and less commonly, fungal or parasitic, with similar etiologies in encephalitis, although viral causes are most common. Have a high index of suspicion for meningitis in those with immunosuppression (particularly acquired immunodeficiency syndrome, human immu nodeficiency virus, cancer history, chemotherapy, chronic steroids), which may be associated with more insidious types of meningitis such as Cryptococcus. An LP is indicated for suspected meningitis. If the LP is delayed (e.g., CT, coagulopathy, thrombocytopenia, agitation) and meningitis is strongly suspected, administer antibiotics without TABLE 165-5 Choice of Imaging Modality American College of Radiology Noncontrast Head CT MRI of Brain With and Without Contrast • Trauma • Thunderclap headache • New headache plus focal neurologic deficit or papilledema • Chronic headache plus change in clinical features • New-onset headache plus focal neurologic deficit/papilledema • Possible encephalitis • Possible vertebral/carotid dissection • Horner’s syndrome • Valsalva or coital headache • Immunocompromised individual • Patient with cancer history/current cancer • Suspected temporal arteritis • Intracranial hypotension (low-pressure headache) • Headache with suspected intracranial complication of sinusitis/mastoiditis/ oromaxillofacial origin • New-onset headache in pregnant woman (without contrast) • Headache of trigeminal autonomic origin • Chronic headache with new feature or focal deficit (CT can be first step) American College of Emergency Physicians 2008 Clinical Policy: Which patients with headache require neuroimaging in the ED?
ofacial origin • New-onset headache in pregnant woman (without contrast) • Headache of trigeminal autonomic origin • Chronic headache with new feature or focal deficit (CT can be first step) American College of Emergency Physicians 2008 Clinical Policy: Which patients with headache require neuroimaging in the ED? Patient Presentation Recommendation Headache and new abnormal findings in neurologic examination (focal deficit, altered mental status, altered cognitive function) Level B (emergent noncontrast head CT) New sudden-onset severe headache Level B (emergent noncontrast head CT) HIV-positive patients with a new type of headache Level B (emergent noncontrast head CT) Age >50 with new headache but with normal neurologic examination Level C (urgent noncontrast head CT) Tintinalli_Sec14_p1101-1186.indd 1109 8/2/19 12:08 PM
CT) New sudden-onset severe headache Level B (emergent noncontrast head CT) HIV-positive patients with a new type of headache Level B (emergent noncontrast head CT) Age >50 with new headache but with normal neurologic examination Level C (urgent noncontrast head CT) Tintinalli_Sec14_p1101-1186.indd 1109 8/2/19 12:08 PM 1110 SECTION 14: Neurology delay.32,43 For many patients who are awake and alert without evidence of papilledema or focal neurologic deficit and who have no history to suggest immunocompromised state or new-onset seizure, the head CT can be delayed until after the LP . SUBARACHNOID HEMORRHAGE Subarachnoid hemorrhage resulting from rupture of an intracranial aneurysm carries only a 50% 30-day survival rate. 44,45 Approximately half of survivors have some degree of neurologic impairment. Early detection and appropriate management lead to improved clinical outcome. Only 1% of patients presenting to the ED with headache have subarachnoid hemorrhage. However, 10% to 14% of those complaining of the “worst headache of their life” have subarachnoid hemorrhage. 7,8 Acute onset of a severe headache is subarachnoid hemorrhage until proven otherwise.12,14 Neck pain on history and stiffness on exam are suggestive. 46 Inquire about a family history as outlined above.23 Obtain a noncontrast head CT as the first step in evaluation.47 With third-generation CT equipment, CT scan done within 6 hours of headache onset is reported to have a sensitivity approaching over 99% and specificity over 99%, with a negative predic tive value of 99.4% and positive predictive value of 100%. 46,48 If head CT is negative for blood but suspicion for subarachnoid hemorrhage is strong, or if the patient presents beyond 6 hours of headache onset, the next step is LP to detect blood or xanthochromia in the cerebrospinal fluid. 49 For further discussion, see Chapter 166, “Spontaneous Subarachnoid and Intracerebral Hemorrhage. ” Consultation with a neurologist or neurosurgeon may be appropriate if the history is highly sugges tive of subarachnoid hemorrhage, because both the CT and LP can be normal. 50-52 CT angiogram, magnetic resonance angiogram, MRI with fluid-attenuated inversion recovery/susceptibility-weighted images, 53,54 or four-vessel cerebral angiogram may be reasonable.34 SUBDURAL HEMATOMA AND INTRACEREBRAL HEMORRHAGE Intracranial hemorrhage may occur with or without a history of trauma, in the context of new or progressive headache, and with or without associated neurologic deficit. This is particularly important in the elderly, those with chronic alcohol and substance abuse, and patients using antiplatelet and anticoagulant agents. The antiplatelet agent clopido grel increases the risk of acute intracranial bleeding immediately after trauma, so patients receiving antiplatelet agents and anticoagulants should be screened using head CT, regardless of symptoms. In a pro spective trial of patients with blunt head trauma, 12% of those taking clopidogrel and 5.1% of those taking warfarin had acute intracranial hemorrhage noted on their initial CT scan. The risk of delayed intra cranial hemorrhage was small in both groups (0 of 296 patients taking clopidogrel and 4 of 687 patients taking warfarin). Acute headache with associated vestibular symptoms (vertigo or ataxia) should be considered a cerebellar hemorrhage until proven oth erwise. Cerebellar hemorrhages make up approximately 10% of all intracerebral hemorrhages and may require prompt surgical evacuation of the hematoma to prevent rapid progression to severe disability or death. BRAIN TUMOR Headache in the setting of brain tumor is caused, at least in part, by cerebrospinal fluid flow obstruction and intracranial hypertension.
proximately 10% of all intracerebral hemorrhages and may require prompt surgical evacuation of the hematoma to prevent rapid progression to severe disability or death. BRAIN TUMOR Headache in the setting of brain tumor is caused, at least in part, by cerebrospinal fluid flow obstruction and intracranial hypertension. Headache alone is a rare presentation of brain tumor.57 Clinical signs and symptoms suggesting brain tumor include abnormal neurologic examination, headache worsened by Valsalva maneuver, headache causing awakening from sleep, seizures, recent cancer diagnosis, or mental status change. The absence of these features does not exclude the pos sibility of a brain tumor. In adults, nausea, vomiting, and neurologic deficit are more common than morning or nocturnal headache. 58,59 MRI with and without gadolinium is the study of choice for detecting brain tumors, but cost and limited access make it unfeasible in many settings. A noncontrast CT will identify large masses and edema associated with large masses, but may fail to identify smaller masses. However, noncontrast CT can diagnose hemorrhage secondary to malignancy, account ing for up to 11% of intracerebral hemorrhages. 60 Evaluate for potential barriers to access of medical care in clinical decision making, because additional imaging may be needed at follow-up. CEREBRAL VENOUS THROMBOSIS Cerebral venous thrombosis is a rare, but dangerous, cause of headache, with mean age of 39 years. Consider the diagnosis in patients present ing with new headache symptoms, especially in the presence of certain risk factors. Cerebral venous thrombosis is more common in women, especially in the peripartum period, and in patients with a recent surgi cal history. It is associated with hypercoagulable states such as use of oral contraceptives, hematologic disorders, factor V Leiden homozygous mutation, protein S or protein C deficiency, and anti–thrombin III deficiency. 61 The presentation can vary widely, from a progressive headache developing over days to weeks to, in some instances, a “thunderclap” headache. Similarly, the patient’s clinical appearance can be quite benign, especially early in the course of the illness, or in more severe cases, patients may present with signs of elevated intracranial pressure, seizures (40%), stroke symptoms, and even coma (14%). 62,63 Approximately one third will develop intracerebral hemorrhage.64 In the presence of abnormal imaging (CT, MRI), focal neurologic deficit, or altered mental status, the diagnosis is made definitively with magnetic resonance venography. Given the rare nature of this diagnosis, patients suffering from cerebral venous thrombosis may be undergoing evaluation for other causes of severe headache. An elevated LP opening pressure should raise suspicion of cerebral venous thrombosis in the appropriate clinical setting and prompt further imaging with magnetic resonance venography or consultation with a neurologist. 65,66 LP can safely be performed in patients with cerebral venous thrombosis. POSTERIOR REVERSIBLE ENCEPHALOPATHY SYNDROME Patients with posterior reversible encephalopathy syndrome can present with severe headache, visual changes, seizures, and encephalopathy in the setting of marked blood pressure elevation (usually rapidly developing). It is most common in patients undergoing active treatment with immunesuppressing or -modulating medications or chemotherapeutic agents, as well as in patients with end-stage renal disease. Imaging with MRI typically shows evidence of symmetrical vasogenic edema in the occipital area of the brain, although other areas of the brain can be involved. Treatment involves blood pressure control and supportive care.
ting medications or chemotherapeutic agents, as well as in patients with end-stage renal disease. Imaging with MRI typically shows evidence of symmetrical vasogenic edema in the occipital area of the brain, although other areas of the brain can be involved. Treatment involves blood pressure control and supportive care. REVERSIBLE CEREBRAL VASOCONSTRICTION SYNDROME This condition can mimic subarachnoid hemorrhage (see Table 165-2). Characterized by the occurrence of one or more “thunderclap” head aches, the diagnosis should be considered only when the evaluation for subarachnoid hemorrhage has proven negative. The underlying pathophysiology of the syndrome is poorly understood, but it appears to coexist with a number of other cerebral angiopathies (including posterior reversible encephalopathy syndrome) that are characterized by diffuse cerebral vasospasm. The incidence is greater in women, and the peak age of onset is in the early 40s. Most patients will have more than one thunderclap headache over the course of a few weeks. Severe headache may be the only presenting feature, although some patients can present with seizure or focal neurologic deficit. The key diagnostic feature (multiple areas of cerebral vasoconstriction on cerebral angiog raphy) is most commonly found on follow-up angiography between 2 and 3 weeks after symptom onset. 22 In three published series, the rate of permanent neurologic disability was between 6% and 20%. Reversible cerebral vasoconstriction syndrome, although not widely known among nonneurologists, does not appear to be that rare. One prospective case series included 67 patients diagnosed at a single hospital over a 3-year period of data collection. Initial neuroimaging in these patients may show evidence of nonaneurysmal subarachnoid hemorrhage, ischemic stroke, or intracranial hemorrhage. However, head CT is most commonly normal in these patients. Ultimately, there will be magnetic resonance angiography evidence of cerebral vasoconstriction in all patients, but this may be delayed in appearance. As such, the clinical presentation of thunderclap headache Tintinalli_Sec14_p1101-1186.indd 1110 8/2/19 12:08 PM
ever, head CT is most commonly normal in these patients. Ultimately, there will be magnetic resonance angiography evidence of cerebral vasoconstriction in all patients, but this may be delayed in appearance. As such, the clinical presentation of thunderclap headache Tintinalli_Sec14_p1101-1186.indd 1110 8/2/19 12:08 PM CHAPTER 165: Headache 1111 without evidence of subarachnoid hemorrhage should be the main prompt to making this diagnosis or consulting with a neurologist. TEMPORAL ARTERITIS Temporal arteritis, also known as giant cell arteritis, is an inflammatory condition affecting the small and medium-sized intracranial and extra cranial vessels. Primarily a disease of those >50 years old, its incidence increases with age. In addition to headache (over 80% of patients), associated symptoms may include fatigue, fever, proximal muscle weakness, jaw claudication, or transient ischemic attack symptoms, especially transient visual loss. Sedimentation rate may be elevated, as may C-reactive protein. Check intraocular pressure to exclude glaucoma. Diagnosis is made by the presence of three of the five criteria listed in Table 165-6, with sensitivity of 93.5% and specificity of 91.2%. 69 Begin treatment with prednisone, 60 milligrams PO daily, to minimize morbidity from visual impairment and stroke. Consult with an ophthalmologist to determine optic nerve function and a rheumatologist. It is important to ensure rapid and appropriate follow-up for patients discharged from the ED, ideally with their primary care provider. MIGRAINE The most common non–life-threatening headache in the ED is migraine (see Table 165 -3). Migraine is defined as a headache of moderate to severe intensity that lasts hours (4 to 72 hours on average) and is usually unilateral, pulsatile in quality, typically associated with both photophobia and phonophobia, and generally made worse with physical activity. The POUND mnemonic (see Table 165-3) can be beneficial, as a patient who meets four of five criteria possesses a positive likelihood ratio of 24 for diagnosis of migraine. 70 Migraine can be episodic or chronic and can occur with or without aura. The characteristics of migraine aura vary widely. Among the most common aura symptoms are lightheadedness and visual changes (scotoma and scintillations). Migraines usually start in childhood and peak around age 40 years, with gradual decline thereafter. Prevalence is approximately 5% for males and 15% to 17% for females. Chronic migraine is defined as 5 or more migraine headache days per month over the past 3 months. Migraine sufferers who present to the ED are more likely to be chronic headache sufferers. 71,72 There are many effective treatment options for management of migraine headache, based on randomized controlled trials. Triptans are considered first-line abortive therapy for migraine at home. However, in the ED setting, most patients have failed abortive therapy and require rescue therapy. ED Treatment of Migraine Initial treatment includes IV treatment with dopamine receptor antagonist (droperidol, metoclopramide, pro chlorperazine)73 and NSAIDs ( Table 165-7). Many combinations are effective. Combination with antihistamine (usually diphenhydramine 25 to 50 milligrams IV) is helpful to treat akathisias from antiemetics, although data suggest antihistamines alone are not helpful.74,75 Steroids may be useful to reduce the risk for headache recurrence after ED discharge.76,77 Opiates and barbiturate-containing compounds should not be used routinely for abortive migraine therapy unless other standard treatments fail. Not recommended for routine use are ergotamine and codeine- and tramadol-containing medications, as well as butorphanol and butalbitalcontaining medications.
ED discharge.76,77 Opiates and barbiturate-containing compounds should not be used routinely for abortive migraine therapy unless other standard treatments fail. Not recommended for routine use are ergotamine and codeine- and tramadol-containing medications, as well as butorphanol and butalbitalcontaining medications. 78,79 In pregnancy, there are scant data on treatment of migraine. In general, triptans are contraindicated; acetaminophen, opioids, or corti costeroids can be used. Metoclopramide (U.S. Food and Drug Admin istration category B) may be used. NSAIDs may be also used until the third trimester. Ergotamines and combination agents with caffeine and isometheptene are absolutely contraindicated in pregnant women. Upon discharge from the ED, more than half of patients will have some residual headache, and there is an increased rate of recurrence of headache within the first 3 days after discharge. 76,77,80 A prescription for abortive medications should form part of the discharge plan for patients discharged from the ED with a diagnosis of migraine. Providers should be familiar with one or two fast-acting triptans (such as sumatriptan, sold as Imitrex in the United States, and rizatriptan, sold as Maxalt in the United States), as well as combinations of triptans, such as sumatriptan/naproxen (sold as Treximet in the United States), or combination drugs, such as Midrin (acetaminophen, 325 milligrams/ dichloralphenazone, 100 milligrams/isometheptene, 65 milligrams). OCCIPITAL NEURALGIA Occipital neuralgia is characterized by paroxysms of lancinating pain at the back of the head, in the distribution of the greater and/or lesser occipital nerve. Patients describe the pain as stabbing or electric shock– like in quality, with hypersensitivity in the distribution of the affected nerve. Most cases are attributed to chronic neck tension or unknown causes. However, the condition can be associated with osteoarthritis or degenerative disease of the upper cervical spine. Occipital nerve block typically results in marked improvement of symptoms, and the results can persist for weeks after the injection. The procedure is both diagnostic and therapeutic. The procedure can be performed with ease in any setting and requires minimal expertise. IDIOPATHIC INTRACRANIAL HYPERTENSION (PSEUDOTUMOR CEREBRI SYNDROME) Idiopathic intracranial hypertension, also known as pseudotumor cere bri, is most common in obese women. The incidence is 19.3 per 100,000 obese women between the ages of 20 and 44 years and has increased with the obesity epidemic. The most prominent symptoms include headache (84%), transient visual obscurations (68%), back pain (53%), and pulsatile tinnitus (52%). Only 32% of patients report visual loss. Untreated, idiopathic intracranial hypertension can lead to permanent visual impairment if not recognized and treated appropriately. The diagnostic criteria include papilledema with an otherwise normal neurologic examination and elevated opening pressure on LP (>25 cm 2O in adults and >28 cm H 2O in children), in the setting of normal cerebrospinal fluid composition and normal imaging (having excluded other causes of raised intracranial pressure). Treatment is focused on preservation of vision. A variant of pseudotumor has been identified that does not present with papilledema but may present with the other clinical features of pseudotumor cerebri, along with abducens nerve palsy (unilateral or bilateral).
excluded other causes of raised intracranial pressure). Treatment is focused on preservation of vision. A variant of pseudotumor has been identified that does not present with papilledema but may present with the other clinical features of pseudotumor cerebri, along with abducens nerve palsy (unilateral or bilateral). In the absence of either papilledema or abducens nerve palsy, the diagnosis of pseudotumor without papill edema can be made if at least three of the following neuroimaging findings are present: empty sella, flattening of the posterior aspect of the globe, distention of the perioptic subarachnoid space with or without a tortuous optic nerve, and transverse venous sinus stenosis. LP is necessary to make the diagnosis of idiopathic intracranial hypertension, and concomitant removal of a volume of cerebrospinal fluid can provide temporary relief of symptoms. However, subjective improvement of symptoms after LP is not reliable in establishing the diagnosis. 82 Perform the LP with the patient in the lateral decubitus position, without sedation (which may cause mild hypercapnia and, subsequently, an elevated cerebrospinal fluid pressure measurement). The knees should be extended for measurement of cerebrospinal fluid TABLE 165-6 American College of Rheumatology Criteria for Diagnosis of Temporal Arteritis Clinical Features Comments Age at disease onset ≥50 years New headache Onset or type Temporal artery abnormality Tenderness to palpation of temporal arteries Decreased pulsation of temporal arteries Erythrocyte sedimentation rate ≥50 mm/h Westergren method Abnormal artery biopsy (can be done after initiating steroids) Vasculitis Predominance of mononuclear cell infiltration or granulomatous inflammation Multinucleated giant cells Tintinalli_Sec14_p1101-1186.indd 1111 8/2/19 12:08 PM
pulsation of temporal arteries Erythrocyte sedimentation rate ≥50 mm/h Westergren method Abnormal artery biopsy (can be done after initiating steroids) Vasculitis Predominance of mononuclear cell infiltration or granulomatous inflammation Multinucleated giant cells Tintinalli_Sec14_p1101-1186.indd 1111 8/2/19 12:08 PM 1112 SECTION 14: Neurology pressure, and the base of the manometer should be level with the right atrium. Elevated cerebrospinal fluid pressures can occur in the setting of the Valsalva maneuver, such as breath holding and crying, and if the pressure is measured in the sitting position. Cerebrospinal fluid can be removed in multiple aliquots, measuring cerebrospinal fluid pressure after each removal, until a target pressure of 15 to 20 cm H 2O is achieved. Determine the opening pressure. In general, removal of 1 mL of cere brospinal fluid will lower the cerebrospinal fluid pressure by about 1 cm H2O.83 To avoid lowering the pressure excessively, first remove 1 mL for every 1 cm H2O reduction desired, and then remeasure cerebrospinal fluid pressure. Excess cerebrospinal fluid removal can result in intra cranial hypotension and a “low-pressure headache, ” which may require epidural blood patch for relief. Ultrasound assessment of the optic nerve sheath is helpful when considering the diagnosis of idiopathic intracranial hypertension as a cause of headache. Literature suggests US is sensitive for detection of increased ICP , with sensitivity over 90% and specificity ranging from 67% to 85%. A disadvantage is the lack of a uniform cut-off level for the diagnosis of increased ICP . Optic nerve sheath diameter < 5 mm diameter is considered normal and > 6 mm abnormal, but the significance of measure ments between 5-6 mm are controversial. However, a normal sheath diameter does not exclude a life-threatening disease, and US should be used in conjunction with other clinical assessments. Oral acetazolamide can be effective in lowering intracranial pres sure and decreasing symptoms of idiopathic intracranial hypertension. Treatment is typically started at 250 to 500 milligrams twice a day. The dose can be increased to as much as 4 grams/d, but dose escalation is associated with significant side effects (paresthesias, fatigue, decreased libido, metallic taste) and should be done under the supervision of a neurologist or ophthalmologist for ongoing monitoring of papilledema and visual field testing to minimize the risk of visual loss. 85 Long-term interventional management may include cerebrospinal fluid shunting and optic nerve sheath fenestration for failing vision. For obese patients, weight loss is recommended. INTRACRANIAL HYPOTENSION The headache of intracranial hypotension (low-pressure headache) is most commonly associated with recent dural penetration, either during LP , epidural anesthesia, or any operative procedure that involves opening the dura. Using a noncutting needle reduces the risk of post-LP headache. 86 Rarely, intracranial hypotension can occur spontaneously or in association with head or spine trauma. 87-89 Clinical features include headache that increases in severity with upright posture but improves or resolves in the supine position. Associated symptoms, such as alterations in hearing or vision, nausea, vomiting, diplopia, and visual changes, may occur. MRI, with and without contrast, confirms the diagnosis by showing diffuse enhancement of the meninges. The LP , if performed, should have an opening pressure <6 cm 2O. Most patients experience spontaneous resolution of their symptoms. Evidence to support treatments such as IV fluid resuscitation and IV caffeine is limited. The most effective therapy for low-pressure headache is an epidural blood patch, typically performed by anesthesiologists.
hould have an opening pressure <6 cm 2O. Most patients experience spontaneous resolution of their symptoms. Evidence to support treatments such as IV fluid resuscitation and IV caffeine is limited. The most effective therapy for low-pressure headache is an epidural blood patch, typically performed by anesthesiologists. 87,90 TABLE 165-7 Treatment Options for Migraine Headache Drug Dosing Contraindications Precautions and Pregnancy Category Notes Ketorolac 10–30 milligrams IV or IM History of peptic ulcer disease (especially in elderly) Pregnancy category B Avoid in third trimester 10, 15, and 30 milligrams are equivalent in pain relief Prochlorperazine 5–10 milligrams IV or PR Pregnancy category C Drowsiness Dystonic reactions Antiemetic Concurrent: diphenhydramine Metoclopramide 10 milligrams IV Pregnancy category B Drowsiness Dystonic reactions Antiemetic Concurrent: diphenhydramine Droperidol 2.5 milligrams IV slow, or 2.5 milligrams IM Pregnancy category C QT interval prolongation and/or torsades de pointes Concurrent: diphenhydramine Chlorpromazine 7.5 milligrams IV Pregnancy not classified Hypotension Drowsiness Dystonic reactions Antiemetic Pretreat with: normal saline bolus to minimize hypotension Concurrent: diphenhydramine Magnesium sulfate 2 grams IV over 30 min Pregnancy category D but effective in preeclampsia and eclampsia Nonvalidated Methylprednisolone 125 milligrams IV or IM Rescue therapy Nonvalidated Dexamethasone 6–10 milligrams IV Rescue therapy Adjunctive therapy to reduce recurrence Sumatriptan 6 milligrams SC Ischemic heart disease Uncontrolled hypertension Basilar or hemiplegic migraine Pregnancy category C Dihydroergotamine (DHE) 1 milligram IV over 3 min Pregnancy Uncontrolled hypertension Ischemic heart disease Recent sumatriptan use (within 24 h) Basilar or hemiplegic migraine Pregnancy category X Nausea Vomiting Diarrhea Abdominal pain Pretreat with antiemetic Valproate 500 milligrams IV Pregnancy Pregnancy category X Nonvalidated Ketamine 0.1–0.3 milligram/kg IV Hypertension, tachycardia Emergence reaction Pregnancy category B May be used in patients with head trauma, as it does not increase intracra nial pressure Tintinalli_Sec14_p1101-1186.indd 1112 8/2/19 12:08 PM
etic Valproate 500 milligrams IV Pregnancy Pregnancy category X Nonvalidated Ketamine 0.1–0.3 milligram/kg IV Hypertension, tachycardia Emergence reaction Pregnancy category B May be used in patients with head trauma, as it does not increase intracra nial pressure Tintinalli_Sec14_p1101-1186.indd 1112 8/2/19 12:08 PM CHAPTER 165: Headache 1113 CARCINOMATOUS MENINGITIS About 5% to 10% of patients with cancer develop leptomeningeal metastases. In addition to headache, cranial nerve abnormalities (typi cally more than one) and other neurologic findings may be present. Risk factors for carcinomatous meningitis include aggressive lymphoma subtypes and uncontrolled systemic disease. In suspected patients, the appropriate testing would include MRI with and without contrast (to evaluate for meningeal enhancement). Obtain MRI before LP , as MRI evidence of meningeal enhancement is common after LP and may confound the diagnosis. LP may reveal an elevated opening pressure (>20 cm H 2O). Cerebrospinal fluid analysis should include cytology (solid tumors) or flow cytometry (hematologic tumors). Malignant cells degrade quickly, so timely review of cerebrospinal fluid is important. CLUSTER HEADACHE Cluster headaches (Table 165-4) occur in about 0.4% of the general population and can mimic dental pain. More common in men, cluster headaches typically start in adulthood and tend to occur in “clusters, ” with a circadian and circannual pattern, recurring daily for more than a week and remitting for at least 4 weeks. Episodes are typically unilat eral and excruciating, but brief and self-limited. Up to 10% of patients will experience a more chronic form, with fewer episodes of remission. Associated ipsilateral symptoms are common (Table 165-4), and a distinguishing feature of this headache is the need for the patient to “pace, ” in contrast to the patient with migraine, who prefers to lie still in a quiet and dark room. Treatment consists of 100% oxygen administered at 12 L/min for 15 minutes through a nonrebreathing facemask. 92,93 Sumatriptan, 6 milligrams SC, can also be used, as can single-dose intranasal lidocaine 10% solution (effective in over one third of patients). HYPERTENSIVE HEADACHE There is no compelling evidence linking mild to moderate hypertension with headache. Several studies using ambulatory blood pressure monitoring have found no association between mild to moderate high blood pressure (systolic blood pressure <180 mm Hg and/or diastolic blood pressure <120 mm Hg) and patient self-reported headache. Uncontrolled hypertension can be associated with headache, especially in conditions where there is a rapid and marked rise in blood pressure, such as pheochromocytoma, posterior reversible encephalopathy syndrome, hypertensive crisis, preeclampsia, and eclampsia.95 METABOLIC CAUSES OF HEADACHE Metabolic headaches are hallmarked by deterioration in the setting of a disorder of homeostasis and typically improve after resolution of the disorder of homeostasis (Table 165-8). CAROTID AND VERTEBRAL ARTERY DISSECTION Cervical artery dissection, including both the carotid and vertebral arteries, is an important diagnosis, although it can be difficult to make in the ED. Cervical artery dissection accounts for 2% of all strokes and up to one quarter of strokes in young adults. 96,97 Cervical trauma, including coughing, sneezing, and physical activity, is associated in close to 40% of cases. Headache is the predominant symptom, although some patients may present with neck or facial pain. Delayed onset of neurologic symptoms by several days is common. 98-100 Internal carotid dissection will present with anterior circulation symptoms, while vertebral artery dissection more commonly presents with posterior circulation symptoms.
dominant symptom, although some patients may present with neck or facial pain. Delayed onset of neurologic symptoms by several days is common. 98-100 Internal carotid dissection will present with anterior circulation symptoms, while vertebral artery dissection more commonly presents with posterior circulation symptoms. Other symptoms include cranial nerve palsies, vision changes, Horner’s syndrome, and pulsatile tinnitus. Diagnosis requires CT with IV contrast or MRI/magnetic resonance angiography. 101-103 CARBON MONOXIDE TOXICITY Carbon monoxide toxicity is a dangerous etiology of headache. Smoke inhalation, heating sources with inadequate ventilation, and engine exhaust exposure are the most common etiologies. Symptoms include headache, myalgias, nausea/vomiting, and dizziness, although confu sion, loss of consciousness, focal neurologic deficit, and death can result from severe exposure. Carbon monoxide toxicity should be suspected in the setting of multiple household members and pets with similar symptoms including headache and concerning exposure. 104,105 Pulse oximetry should not be relied on for screening or diagnosis, and co-oximetry is required. 106 Treatment includes oxygen supplementation, although hyperbaric oxygen therapy may be required in specific circumstances.107 PITUITARY APOPLEXY Pituitary tumor apoplexy is a rare clinical diagnosis that is usually due to spontaneous hemorrhage or infarction of a preexisting pituitary adenoma. 108 Pregnancy, head trauma, pituitary radiation, and dopamine agonist therapy are other risk factors.108-110 The earliest symptom is sudden, severe headache. The headache location tends to be retro-orbital, bifrontal, or suboccipital. Between 63% and 100% of patients will experience headache. 108 Associated symptoms may include ophthalmoplegia, reduced visual acuity, visual field defects (up to 75% of patients), altered consciousness, meningismus, and nausea and vomiting. CT (noncontrast) and MRI may show a sellar mass and hemorrhage. In the first 1 to 2 hours, the hyperacute hemorrhage may be easier to see on CT than MRI. MRI should be pursued after negative CT. Pituitary adeno mas and cerebral aneurysms have a co-occurrence rate of 7.4%. 108 Pituitary tumor apoplexy requires immediate treatment with corticosteroids and urgent neurosurgical consultation. The treatment usually requires consultations from endocrinology, ophthalmology, and neurology with intensive care monitoring. THIRD VENTRICLE COLLOID CYSTS Colloid cysts of the third ventricle are a rare cause of acute neurologic deterioration and sudden death. The colloid cyst is usually congenital, slow growing, and benign, accounting for about 0.2% to 2% of all intra cranial tumors, but it is the most common tumor of the third ventricle. The usual clinical presentation is a history of severe paroxysmal and episodic attacks of (typically frontal) headache associated with nausea TABLE 165-8 Metabolic Causes of Headache History Examples Treatment Hypoxia/hypercapnia High altitude Acetaminophen/ibuprofen Acetazolamide 125–250 milligrams twice a day Steroids (dexamethasone) Prophylaxis: acetylsalicylic acid, 320 milligrams at 4-h intervals, starting 1 h prior to ascent; repeat 3 times Air travel Nonsteroidal anti-inflammatory drugs (NSAIDs), pseudoephedrine, and nasal decongestants Pulmonary disease Congestive heart failure Sleep apnea
5–250 milligrams twice a day Steroids (dexamethasone) Prophylaxis: acetylsalicylic acid, 320 milligrams at 4-h intervals, starting 1 h prior to ascent; repeat 3 times Air travel Nonsteroidal anti-inflammatory drugs (NSAIDs), pseudoephedrine, and nasal decongestants Pulmonary disease Congestive heart failure Sleep apnea Dialysis Analgesics during dialysis Autonomic dysreflexia (typical in quadriplegia) Seated position Remove/loosen clothing Scrutinize for bladder distention/ bowel impaction Other Hypothyroidism Fasting Cardiac cephalgia (associated with myocardial ischemia) Tintinalli_Sec14_p1101-1186.indd 1113 8/2/19 12:08 PM