20: Headache

Headache is one of the most common physical complaints. Because less than 1% of all headaches are life-threatening, the challenge is to reassure and appropriately treat patients with benign headaches while finding the rare, life-threatening headache without excessive evaluation.

Headaches are classified as primary or secondary. Primary headaches are syndromes unto themselves rather than signs of other diseases. Although potentially disabling, they are reliably not life-threatening. Secondary headaches are symptoms of other illnesses. Unlike primary headaches, secondary headaches are potentially dangerous.

The distinction of primary and secondary headaches is useful diagnostically. Primary headaches, such as tension headaches, are diagnosed clinically, sometimes using diagnostic criteria (the most commonly used are published by the International Headache Society, IHS). Traditional diagnostic studies (laboratory studies, radiology, pathology) cannot verify the diagnosis. Secondary headaches, such as headaches caused by central nervous system (CNS) tumors, often can be definitively diagnosed by identifying the underlying disease.

Clinically, primary and secondary headaches can be difficult to distinguish. The single most important question when developing a differential diagnosis for a headache is, “Is this headache new or old?” Chronic headaches tend to be primary, while new-onset headaches are usually secondary. This is the first and most important pivotal point in diagnosing headaches. This distinction is not perfect. There are some chronic headaches that are secondary headaches (headaches caused by cervical degenerative joint disease for example) and even classic, primary headaches (such as migraines) can present as a new headache. The differentiation of old versus new also depends on how rapidly a patient brings his or her symptoms to medical attention. This being said, the classification of headaches as primary vs secondary and new vs old provides not only a memorable framework for the differential diagnosis but also a clinically useful structure by which the differential can be organized by pivotal points. The differential diagnosis appears below. Figure 20-1 shows the potential diagnoses in a more algorithmic form as they are often considered clinically.

1. Old headaches

   1. Primary

      1. Tension headaches

      2. Migraine headaches

      3. Cluster headaches

   2. Secondary

      1. Cervical degenerative joint disease

      2. Temporomandibular joint syndrome

      3. Headaches associated with substances or their withdrawal

         • (1) Caffeine

         • (2) Nitrates

         • (3) Analgesics (often presenting as chronic daily headaches)

         • (4) Ergotamine

2. New headaches

   1. Primary

      1. Benign cough headache

      2. Benign exertional headache

      3. Headache associated with sexual activity

      4. Benign thunderclap headache

      5. Idiopathic intracranial hypertension (pseudotumor cerebri)

   2. Secondary

      1. Infectious

         • (1) Upper respiratory tract infection

         • (2) Sinusitis

         • (3) Meningitis

      2. Vascular

         • (1) Temporal arteritis

         • (2) Subarachnoid hemorrhage (SAH)

         • (3) Parenchymal hemorrhage

         • (4) Malignant hypertension

         • (5) Cavernous sinus thrombosis

      3. Space-occupying lesions

         • (1) Brain tumors

         • (2) Subdural hematoma

      4. Medical morning headaches

         • (1) Sleep disturbance

         • (2) Night-time hypoglycemia

The severity and chronicity of the headaches are pivotal points in this case that enable us to limit the differential. Although Mr. M’s headaches are severe, they have to be classified as old headaches since they have been occurring for years. This fact is reassuring, meaning that his headaches are most likely a primary headache syndrome. In a young healthy person with chronic headaches, migraine, tension, and cluster headaches are most likely. Given the severity of the headaches, migraines are more likely than tension headaches. Given the severe, throbbing nature of the headaches, a vascular cause should at least be considered. An intracranial aneurysm could cause similar symptoms, but the chronicity makes this less likely. Table 20-1 ranks the differential diagnosis considering the demographic information, risk factors, symptoms and signs available to us at this point.

Severity is less important than quality in distinguishing a new headache from an old headache. A severe headache that is identical in quality to chronic headaches is less worrisome than a mild headache that is dissimilar to any previous headache.

Leading Hypothesis: Migraine Headaches

Textbook Presentation

Migraines most often first present in women in their teens or 20s. The headaches are unilateral and throbbing and are severe enough to make it impossible to do work during an attack. They are occasionally preceded by about 20 minutes of flickering lights in a visual field (aura). Patients often find it necessary to lie in a dark, quiet room.

Disease Highlights

1. The description of migraine headaches adopted by the IHS is, “Recurring headache disorder manifesting in attacks lasting 4–72 hours. Typical characteristics of headache are unilateral location, pulsating quality, moderate or severe intensity, aggravation by routine physical activity and association with nausea, and/or photophobia and phonophobia.”

2. Migraine headaches are a chronic headache syndrome caused by a neurovascular disorder. Neural events lead to intracranial vasodilatation.

3. They may begin at any age but most commonly begin during adolescence.

4. They are more common (2–3 times) and more severe in women than men.

5. Auras frequently accompany migraines.

   1. Somewhere between 33% and 75% of patients with migraines have auras. Of all people with migraine,

      1. 18% always have auras

      2. 13% sometimes have auras

      3. 8% have auras without headaches.

   2. Auras are usually visual, precede the headache, and last for about 20 minutes.

   3. Descriptions of auras

      1. Frequently, patients will initially describe a blind spot.

      2. Auras usually involve 1 portion of the visual field.

      3. Auras may vary. The frequency of some types of aura is given in Table 20-2.

      4. Scintillating scotoma often occur. These are often described as flashing lights, spots of light, zigzag lines, or squiggles.

         Migraine auras are stereotypical. Listening closely to patients with migraines describe their aura will make it easy to recognize auras in other patients.

Evidence-Based Diagnosis

1. Migraine headaches are among the most severe of all the recurrent headache syndromes. (Cluster headache is the other primary headache that causes severe pain.)

   1. They should be considered in any patient with headaches severe enough to be the chief complaint at a doctor visit.

   2. Of initial visits for headaches in the primary care setting, 90% meet criteria for migraines.

      The diagnosis of migraine headache should be seriously considered in any patient who has recurrent headaches that cause disability.

2. As with other primary headaches, diagnosis is guided by the IHS’s diagnostic criteria rather than by diagnostic tests.

3. The criteria for migraines are divided into migraines with and without aura.

   1. Migraine without aura

      1. A patient must have at least 5 attacks that last 4–72 hours.

      2. The headache must have 2 of the following qualities:

         • (1) Unilateral pain

         • (2) Pulsating pain

         • (3) Moderate to severe (must limit activity)

         • (4) Aggravated by routine physical activity

      3. And have 1 of the following associated symptoms:

         • (1) Nausea and/or vomiting

         • (2) Photophobia or phonophobia

   2. Migraine with aura

      1. Definition: “Recurring disorder manifesting in attacks of reversible focal neurological symptoms that usually develop gradually over 5–20 minutes and lasting less than 60 minutes.” A migraine-type headache usually follows the aura symptoms. Less commonly, auras can be followed by a headache that lacks migrainous features or auras can occur with no subsequent headache.

      2. A patient must have at least 2 attacks.

4. It is important to remember that diagnostic criteria, although helpful, need to be used carefully when applied to an individual patient. A patient who clearly has the disease in question may not perfectly fit the criteria. Consider these data about some of classic migraine symptoms:

   1. 50% of patients with migraines have nonpulsatile headaches.

   2. 40% have bilateral headaches.

      Diagnostic criteria are more helpful for research than patient care. They should be used cautiously with individual patients.

5. There are other less common types of migraine.

   1. These include headaches with aura lasting longer than 60 minutes and migraine aura without a headache.

   2. These syndromes are difficult to diagnose and require exclusion of other diseases (such as cerebrovascular accident, transient ischemic attack, or retinal detachment) that could cause similar symptoms.

6. Besides the diagnostic criteria, there are many other aspects of the history that are suggestive of migraine headaches.

   1. A systematic review suggested the mnemonic POUNDing as a diagnostic test for migraines.

      1. Is the headache pulsatile?

      2. Does it last between 4 and 72 hours without medications?

      3. Is it unilateral?

      4. Is there nausea?

      5. Is it disabling?

   2. If 4 or 5 questions are answered with “Yes,” the LR+ is 24, which rules in the diagnosis of migraine headache.

   3. Another review provided test characteristics for various headache qualities in distinguishing migraines from tension headaches. Table 20-3 shows those characteristics that have at least a moderate effect on posttest probability.

   4. When differentiating migraines from tension headaches, nausea is an important clue to migraines.

   5. Interestingly, some commonly considered characteristics, such as headache duration and relationship of headache to stress, weather, menses, fatigue, and odors, were not helpful in differentiating migraines from tension headaches.

   6. Presence of a family history was helpful in making the diagnosis with a LR+ of 5.0.

   7. Patients with migraines are also more likely to have had vomiting attacks as children and to have suffered from motion sickness.

7. Given the severity of migraine, a common issue that comes up is whether a patient with a probable migraine undergos neuroimaging. The following are predictors of abnormal neuroimaging in patients with headaches and are generally agreed upon indications.

   1. Abnormal neurologic exam or symptoms that are atypical for aura, especially dizziness, lack of coordination, numbness or tingling, or worsening of headache with the Valsalva maneuver

   2. Increasing frequency of headaches or a change in headache quality or pattern

   3. Headaches that awaken patients from sleep

   4. New headaches in patients over 50

   5. First headache, worst headache, or abrupt-onset headache

   6. New headache in patients with cancer, immunosuppression, or pregnancy

   7. Headache associated with loss of consciousness

   8. Headache triggered by exertion

   9. Special consideration should be given to a person who is receiving warfarin therapy.

Treatment

1. Treatment of migraines is either abortive or prophylactic.

2. Abortive therapy

   1. Abortive therapy should be used at the very first sign of a migraine. Patients should be advised not to wait until they “are sure it is a migraine.”

   2. Effective drugs are outlined in Table 20-4 with the individual considerations mainly from the consensus comments from the US Headache Consortium.

3. Prophylactic therapy

   1. Prophylactic therapy is instituted when patient and doctor agree that the migraines are frequent enough, severe enough, or persistent enough to warrant regular medications.

   2. Prophylactic therapy does not need to be used every day. It can be used only around the times that migraines predictably occur (such as perimenstrually).

   3. There are many effective medications in multiple classes. Some of the most effective and commonly used are:

      1. Beta-blockers

         • (1) Propranolol

         • (2) Metopolol

         • (3) Timolol

      2. Antidepressants

         • (1) Amitriptyline

         • (2) Venlafaxine

      3. Anticonvulsants

         • (1) Valproic acid

         • (2) Topiramate

Mr. M’s headaches fulfill the criteria for migraine headaches. They are pulsatile, unilateral, disabling, and associated with nausea, thus fulfilling 4 of the POUNDing criteria. The history of motion sickness provides another clue. The increasing frequency and severity of the headaches is somewhat worrisome, and neurologic imaging would be reasonable but not entirely necessary given the high positive likelihood of the POUNDing criteria.

Alternative Diagnosis: Tension Headaches

Textbook Presentation

Tension headaches are the most common type of headache. They generally occur a few times each month and are described as bilateral and squeezing. They are usually relieved with over-the-counter analgesics and are seldom severe enough to cause real disability.

Disease Highlights

1. The IHS definition of episodic tension-type headache is, “Recurrent episodes of H/A lasting minutes to days. The pain is typically pressing/tightening in quality, of mild or moderate intensity, bilateral in location and does not worsen with routine physical activity. Nausea is absent, but photophobia or phonophobia may be present.”

2. Most common type of headache; the 1-year prevalence of tension headaches is 63% in men and 86% in women.

3. The IHS criteria divide tension headaches into multiple subtypes: episodic, chronic, with or without associated tenderness of pericranial muscles.

4. The pathophysiology of tension headaches is still a topic of debate.

   1. Episodic tension headaches are likely related to tenderness and spasm in the pericranial muscles while chronic tension headaches are related to changes in the CNS caused by the chronic pain of tension headaches.

   2. There is evidence to suggest that people who suffer from more frequent tension headaches have higher levels of perceived stress and lower pain thresholds than those without headaches.

5. Tension headaches can be troublesome but are seldom disabling.

Evidence-Based Diagnosis

1. Because tension headaches are the most common form of headaches, they are the default diagnosis in almost every patient with a mild to moderate headache syndrome.

2. A detailed history and physical exam is required to exclude other headache syndromes that require specific treatment.

3. Special attention should be given to excluding migraines.

4. The IHS diagnostic criteria for episodic tension headaches are:

   1. At least 10 previous headaches

   2. Duration of 30 minutes to 7 days

   3. 3 of the following:

      1. Pressing or tightening (nonpulsating) quality

      2. Mild to moderate in severity (inhibits but does not prevent activity)

      3. Bilateral

      4. Not aggravated by routine activity

   4. No nausea or vomiting

   5. Photophobia or phonophobia may be present, but not both

5. Chronic tension-type headaches often develop from the more common episodic headaches. These are similar in quality but occur at least 15 days of the month.

   1. Chronic tension-type headaches are commonly referred to chronic daily headaches.

   2. Chronic tension-type headaches may often be caused by overuse of analgesic drugs used to treat headaches.

Treatment

1. Episodic tension headaches

   1. Usually treated by patients without the input of a physician.

   2. Simple analgesics (acetaminophen or nonsteroidal antiinflammatory drugs [NSAIDs]) are the basis of most treatment.

   3. For more severe headaches, combinations that include caffeine or codeine can be used.

   4. In patients with frequent, but still episodic tension headaches, efforts at stress reduction are helpful.

2. Chronic tension headaches

   1. These are often quite difficult to treat especially if they have been caused by medication overuse.

   2. One of the first interventions in treating chronic tension headaches should almost always be “detoxification” from the patient’s regimen of pain medications.

      1. Long-term use of many headache medications has the potential to cause or exacerbate chronic tension headaches.

      2. The most common culprit medications are ergotamine, NSAIDs, caffeine, and opioids.

      3. Detoxification can be difficult and occasionally requires hospitalization.

   3. While all previous medications are being withdrawn, the addition of tricyclic antidepressants (TCAs) and stress management, either alone or in combination, are effective.

      1. TCAs work faster than stress management.

      2. Even a combination of both TCAs and stress management only reduce headache frequency and severity by about 50%.

Alternative Diagnosis: Cluster Headaches

Textbook Presentation

Cluster headaches are severe headaches that occur in young men, often beginning in their 20s. The headache is unilateral, usually occurring around the eye or temporal region and is associated with ipsilateral conjunctival injection, lacrimation, nasal congestion, or rhinorrhea. Sufferers are often restless during attacks.

Disease Highlights

1. The prevalence of cluster headaches is about 0.1%. They occur more commonly in men (4:1).

2. The headaches are unilateral, severe, and are associated with autonomic findings related to both parasympathetic overactivity and sympathetic underactivity.

3. Cluster headaches are generally brief, lasting from 15 minutes for 3 hours.

4. The headaches occur in clusters with frequent headaches occurring for 6–12 weeks before a headache-free period.

Evidence-Based Diagnosis

1. Classic cluster headaches present in a memorable, stereotypical way.

2. The IHS criteria for a cluster headache are:

   1. The patient must have at least 5 attacks.

   2. The headache must last 15–180 minutes; be severe; and be characterized by unilateral pain that is orbital, supraorbital, or temporal.

   3. The headache is accompanied by at least 1 of the following:

      1. Ipsilateral conjunctival injection and/or lacrimation

      2. Ipsilateral nasal congestion and/or rhinorrhea

      3. Ipsilateral eyelid edema

      4. Ipsilateral forehead and facial sweating

      5. Ipsilateral miosis and/or ptosis

      6. A sense of restlessness or agitation

   4. Attacks occur anywhere from every other day to 8/day during a cluster.

Treatment

1. Treatment for cluster headaches is similar to the treatment for migraines in that one may use either acute abortive therapies or prophylactic therapies.

2. Abortive therapy

   1. High-flow oxygen is the treatment with the least side effects and best evidence base.

   2. Triptans, similar to those used in the treatment of migraines, are also effective.

3. Prophylactic therapy

   1. Verapamil is usually considered the first-line therapy for preventing cluster headaches.

   2. Corticosteroids and topiramate have also been used successfully.

Alternative Diagnosis: Headache due to Unruptured CNS Aneurysm

Textbook Presentation

The classic presentation of a headache caused by a CNS aneurysm is a unilateral and throbbing headache that is new in a middle-aged patient.

Disease Highlights

1. CNS aneurysm may present in 3 ways.

   1. Asymptomatic detection: This commonly occurs when a patient has a ruptured aneurysm and another, nonruptured aneurysm is found during the evaluation.

   2. Acute rupture or expansion (discussed later in the chapter)

   3. Chronic headache

2. The studies of the chronic headaches caused by unruptured aneurysms are, by their nature, somewhat flawed since they must be retrospective.

Evidence-Based Diagnosis

1. The headaches of unruptured aneurysms are nonspecific.

   1. One study looked retrospectively at the symptoms of 111 patients referred for therapy of unruptured aneurysms; 54 of the patients had symptoms referable to the aneurysm at the time of diagnosis.

   2. Of the 54 patients with symptoms, 35 (65%) had chronic symptoms.

   3. In 18 of these 35 patients, the chronic symptom was headache without other neurologic signs.

   4. Patient’s headaches were divided equally between unilateral and bilateral.

2. Neuroimaging

   1. CT angiography and magnetic resonance angiography are very sensitive means of detecting CNS aneurysms.

      1. Sensitivity for aneurysms > 1 cm in diameter is probably 100%.

      2. Sensitivity for all aneurysms is lower (62% for CT and 45% for MRI).

         • (1) Aneurysms < 1 cm can, rarely, cause symptoms. These symptoms may include chronic headaches.

         • (2) Repair of aneurysms < 1 cm in a patient who has not had a previous rupture is generally not recommended since the rupture rates are so low.

   2. Traditional angiography

      1. Considered the gold standard for diagnosis

      2. Usually required prior to repair

      3. There are case reports of small aneurysms being missed on traditional angiography and being seen on CT and magnetic resonance angiography.

Treatment

1. The treatment of CNS aneurysms can be accomplished with neurosurgical or endovascular procedures.

2. Management decisions are difficult in a patient with a small aneurysm and a suspicious headache because there is no definitive way to know whether the aneurysm is causing the headache prior to surgery.

The decision to forgo imaging was difficult. Although the likelihood of finding another cause of headaches was small, the frequency of the patient’s headaches had changed. His complete response to migraine prophylaxis is diagnostic.

Mrs. L’s headaches are of concern because she is older and the headaches are new. Her age and the acuity of the headaches are pivotal features that limit the differential diagnosis. Both these features raise the likelihood that the headaches are secondary and, therefore, potentially dangerous. Morning headaches are classically associated with brain tumors. Edema forms around the CNS lesion while the patient is supine at night leading to headaches from increased intracranial pressure in the morning. Further history is needed, as brain tumors are most likely in patients with other types of cancer.

Morning headaches are also a fairly common symptom of many habits, diseases, and exposures. Headaches associated with substances or their withdrawals are a common cause of morning headaches. Alcohol, caffeine, and carbon monoxide are probably the most common. Morning headaches are frequently the symptoms of diseases that are active at night or that disturb sleep. Nighttime hypoglycemia and obstructive sleep apnea (OSA) are common causes of headaches in this category. Tension headaches should always be in the differential of headaches and may, on occasion, cause morning headaches.

The presence of a new, bitemporal headache in an older patient should raise the possibility of temporal arteritis. Although these headaches are not classically morning headaches, they should still be considered. Temporal arteritis will be discussed later in the chapter. Table 20-5 lists the differential diagnosis.

Even more than with most headaches, a careful history is necessary in a patient with morning headaches.

Many patients seeking care for a headache believe they have a brain tumor. It is important to recognize this—a little definitive reassurance can go a long way.

Leading Hypothesis: Intracranial Neoplasms

Textbook Presentation

Brain tumors classically present with progressive morning headaches associated with focal neurologic deficits.

Disease Highlights

1. Brain tumors are classified as metastatic, primary extra-axial, and primary intra-axial.

2. The relative frequency of types of tumors within each type are listed below:

   1. Metastatic

      1. Lung, 37%

      2. Breast, 19%

      3. Melanoma, 16%

   2. Primary extra-axial

      1. Meningioma, 80%

      2. Acoustic neuroma, 10%

      3. Pituitary adenoma, 7%

   3. Primary intra-axial

      1. Glioblastoma, 47%

      2. Astrocytoma, 39%

3. Metastatic tumors are about 7 times more common than primary tumors. Thus, a patient with known malignancy and new headaches should undergo imaging.

4. Intracranial neoplasms generally present with seizure, focal neurologic signs, or signs of increased intracranial pressure such as headache.

5. Although the presenting symptoms vary with type of tumor, the most common symptoms are:

   1. Headache (about 50% of the time)

   2. Seizure

   3. Hemiparesis

   4. Change in mental status

Evidence-Based Diagnosis

1. History

   1. The history of a patient’s headache is not particularly helpful in making a diagnosis of intracranial neoplasms.

   2. One very good report retrospectively studied 111 patients with brain tumors. The symptoms were nonspecific.

      1. Only 48% of patients had headaches.

      2. Only 17% had classic brain tumor headache (defined as severe, worse in the morning and associated with nausea and vomiting).

      3. 77% of patients met the criteria for tension headaches.

      4. 9% of patients had migraine-like headaches.

      5. The most common qualities were

         • (1) Intermittent, 62%

         • (2) Frontal, 68%

         • (3) Bilateral, 72%

           Brain tumor headaches are nonspecific. A patient with a new headache and a preexisting cancer that could potentially metastasize to the CNS should undergo imaging.

2. Neuroimaging

   1. Contrast-enhanced CT

      1. A reasonable choice for screening patients in whom there is a low suspicion.

      2. The sensitivity of a contrast-enhanced CT for intracranial neoplasm is around 90%.

   2. MRI with contrast is the procedure of choice for imaging brain tumors. The sensitivity of MRI is nearly 100%, and the detail provided often suggests a likely pathology.

Treatment

1. The treatment of brain tumors depends on the pathology.

2. Importantly, patients with signs of increased intracranial pressure or seizure should be hospitalized immediately enabling both rapid diagnosis and treatment.

Given that intracranial neoplasms are rare in patients without preexisting cancers and the presence of morning headaches is a nonspecific finding, it is unlikely that the patient has a brain tumor. The noncontrast head CT was probably a reasonable test to do. Although it is not as sensitive as a contrast-enhanced study, with the low pretest probability it effectively rules out a tumor and, given the patient’s concern, it was an effective method of calming her.

After the normal CT and unrevealing laboratory test results, attention must be turned to possible exposures or the “medical morning headaches.” The patient’s marked drop in her glycosylated Hgb and early morning hypoglycemia are suggestive of a diagnosis.

Alternative Diagnosis: Morning Headaches as Symptoms of Other Diseases

Textbook Presentation

Various diseases can cause headaches that occur predominantly in the morning. The headaches are generally worst upon awakening and then improve as the day progresses. Classically, the more common symptoms of the underlying disease (daytime hypoglycemia with overly controlled diabetes mellitus or daytime somnolence with OSA) are present.

Disease Highlights

1. The most rigorously defined morning headaches are those caused by disturbed sleep. The sleep disturbance can be of almost any etiology.

   1. Primary sleep disturbance

      1. OSA

      2. Periodic leg movement of sleep (PLMS)

   2. Abnormal sleep duration

      1. Excessive sleep

      2. Interrupted sleep

      3. Sleep deprivation

   3. Secondary to another disease

      1. Chronic pain

      2. Depression

2. Hypoglycemia that occurs while asleep or awake can cause headaches.

Evidence-Based Diagnosis

1. The attribution of morning headaches to another disease depends on recognition of the underlying disease, its treatment, and the response of the presenting headache.

2. Recognition of the OSA and nighttime hypoglycemia can be difficult since clinical clues are nonspecific.

   1. Nighttime hypoglycemia should be considered in any patient treated for diabetes with morning headaches. Abnormal nocturnal glucose readings and resolution of headaches with achievement of euglycemia are diagnostic.

   2. Clinical predictors of OSA are poor (See Chapter 18, Fatigue). Polysomnography is diagnostic and will also provide information about PLMS and, sometimes, insomnia related to chronic pain.

      A sleep study is a reasonable diagnostic test in a patient with morning headaches and no readily apparent cause.

Treatment

The treatment of medical morning headaches depends on the cause.

1. Nighttime hypoglycemia: improved management of diabetes mellitus

2. OSA: Continuous positive airway pressure

3. PLMS: Carbidopa and levodopa

4. Pain syndromes: Improved pain control

Alternative Diagnosis: Headaches Associated with Substances or Their Withdrawal

Textbook Presentation

These are headaches that occur in close temporal relation to substance exposure or substance withdrawal. They resolve when the culprit substance is no longer used.

Disease Highlights

1. Many substances can cause headaches acutely, with long-term use, or after their withdrawal.

   1. Acute exposure

      1. Nitrites (“hot dog headache”)

      2. MSG (“Chinese restaurant syndrome”)

      3. Carbon monoxide

   2. Long-term exposure (analgesics)

   3. Withdrawal from acute exposure (alcohol)

   4. Withdrawal from chronic exposure

      1. Caffeine

      2. Opioids

      3. Multiple other medications including estrogen, corticosteroids, TCAs, selective serotonin reuptake inhibitors, and NSAIDs.

2. Of these headaches, caffeine withdrawal, hangovers, and carbon monoxide poisoning are probably the most common or important causes of morning headaches.

Evidence-Based Diagnosis

1. Caffeine withdrawal headaches

   1. The IHS criteria require that:

      1. Patients have a headache that is bilateral or pulsating or both.

      2. Patients drink ≥ 200 mg of caffeine daily for > 2 weeks.

      3. The headaches occur within 24 hours of the last caffeine intake and are relieved within 1 hour by 100 mg of caffeine.

      4. That the headache resolves within 7 days of total caffeine withdrawal.

   2. An average cup of coffee contains about 100 mg of caffeine.

   3. Premium coffees may contain significantly more. A 12-oz coffee at Starbucks contains 260 mg of caffeine.

   4. The average adult American ingests approximately 280 mg of caffeine each day.

   5. Caffeine withdrawal should be suspected if headaches seem to occur when coffee intake changes, such as on weekends and during vacations.

      Caffeine withdrawal should be considered when headaches occur when patients sleep later than usual or occur mainly on weekends or vacations.

2. Carbon monoxide poisoning

   1. Presentation runs the spectrum from mild headache to headache with nausea, vomiting, and anxiety to coma and cardiovascular collapse.

   2. Historical features that increase the suspicion of this diagnosis.

      1. A patient’s headache only occurs in a single location and resolves when the patient is removed from this setting.

      2. Multiple family members or roommates have similar symptoms.

      3. Carbon monoxide poisoning is most common in the winter.

   3. An elevated carboxyhemoglobin level makes the diagnosis. Routine arterial blood gas measurements and pulse oximetry do not detect carbon monoxide poisoning.

      Because carbon monoxide poisoning is potentially life-threatening, the diagnosis should be considered whenever a patient has a potentially consistent history.

Treatment

1. Treatment of headaches associated with substances or their withdrawal depends on the substance.

2. Patients with headaches from carbon monoxide poisoning should be removed from their house while the source is repaired.

3. Patients with caffeine withdrawal headaches should either be weaned off caffeine or counseled on the need to continue regular use (an option generally preferred by medical students).

Adverse effects of medications are common. Although most commonly intrinsic to the medication, they can also be related to inappropriate prescribing or incorrect dispensing.

Both the acuity and severity of this headache are worrisome and pivotal. The onset during exercise is also concerning. This type of headache, one that begins at its peak intensity, is referred to as a thunderclap headache.

Limiting the differential based on the pivotal points of the headache being new and of hyperacute onset, SAH is the leading hypothesis and must not miss diagnosis. His designation of the headache as the “worst headache of his life” is classic for SAH, although the resolution of the pain is not typical. Other headaches can present in similar fashion. Benign thunderclap headache is a rare headache syndrome that is clinically indistinguishable from SAH. Headaches due to cough, exertion, and sexual activity are primary headache syndromes that may mimic SAH. A parenchymal hemorrhage is possible but unlikely given the patient’s age and absence of a history of hypertension.

There are some rare diseases that can occasionally present with a thunderclap headache; these include cerebral venous sinus thrombosis, pituitary apoplexy, carotid dissection, and spontaneous intracranial hypotension from cerebrospinal fluid (CSF) leaks. Table 20-6 lists the differential diagnosis.

A headache that starts abruptly and is reaches its maximal severity within seconds (a thunderclap headache) should be assumed to be caused by a SAH until proven otherwise.

Leading Hypothesis: SAH

Textbook Presentation

A middle-aged patient experiences “the worst headache of his life.” Soon after the headache begins, the patient vomits and develops neck pain and stiffness. Patients may also lose consciousness. If the patient is alert at the time of medical assessment, focal neurologic signs and meningismus may be present on the physical exam.

Disease Highlights

1. SAH is primarily caused by rupture of a saccular aneurysm in or near the circle of Willis (≈ 85%).

2. Aneurysms are present in about 7% of the population.

3. Large aneurysms (> 1 cm) rupture at a rate of about 0.5%/year.

4. The vast majority of ruptures occur in persons 40–65 years old.

5. SAH carries a mortality of about 50%.

6. It is generally accepted that anywhere from 10% to 50% of patients will have a warning or sentinel headache in the weeks preceding the SAH.

   1. Likely caused by the expansion of, or a small leak from, an aneurysm.

   2. This headache is usually the same sort of abrupt onset (thunderclap) headache as SAH but resolves within 24 hours.

   3. About 50% of patients with warning headaches actually seek medical care at the time of the headache.

Evidence-Based Diagnosis

1. Pretest probability

   1. SAH accounts for 1–4% of headaches presenting to the emergency department.

   2. Among headaches presenting to the emergency department, SAH accounts for

      1. 12% of patients with the “worst headache of my life”

      2. 25% of patients with the “worst headache of my life” and neurologic findings

   3. The following findings are common in patients in whom SAH is ultimately diagnosed. (Prevalence figures are estimates from 2 large studies.)

      1. Headache, 90%

      2. In patients presenting with headache, 82.4% report a thunderclap headache, and 99.2% reported the worst headache of their life.

      3. Stiff neck, 75%

      4. Change in mental status, 60%

      5. Stupor or coma, 27%

2. Diagnostic tests

   1. The initial diagnostic test is a noncontrast head CT. The sensitivity of this test varies with the time since the onset of symptoms.

      1. First 12 hours, 97%

      2. 12–24 hours, 93%

      3. Falls to as low as 80% after 2 weeks.

   2. Next to angiography, CSF examination for RBCs and xanthochromia (the result of first oxyhemoglobin and later bilirubin from deteriorating RBCs) is the most accurate diagnostic method.

      1. RBCs are seen immediately in the CSF in 100% of patients. The specificity, however, can be limited by traumatic lumbar punctures.

      2. Sensitivity of RBCs begins to fall after about 24 hours.

      3. Spectrophotometric detection of xanthochromia is 100% specific for SAH.

      4. Most experts suggest delaying the lumbar puncture for 6–12 hours after the onset of a headache (if clinically safe) in a patient with a suspicious headache and normal CT scan since it takes 12–24 hours for the sensitivity to reach nearly 100%.

      5. The sensitivity of xanthochromia remains at 100% for over 1 week.

   3. In all patients with documented SAH, angiography is performed to assist in surgical planning. Angiography might also be done for patients in whom the diagnosis is unclear even after lumbar puncture.

   4. There is less data for the use of MRI in the diagnosis of SAH. MRI maybe as sensitive as CT early in the course of disease and probably remains sensitive for longer.

   5. A recently derived decision rule suggests that SAH may be excluded in patients who arrive at the emergency department with acute nontraumatic headache that reached maximal intensity within 1 hour and who had normal neurologic exam findings if they lack the following findings:

      1. Age over 40 years

      2. Neck pain or stiffness or limited neck flexion on exam

      3. Witnessed loss of consciousness

      4. Onset during exercise

      5. Thunderclap headache

3. Importance of correct diagnosis

   1. About 25% of patients with SAH are initially misdiagnosed.

   2. Patients with less severe clinical presentations are most commonly misdiagnosed.

   3. Patients who are initially misdiagnosed are only about half as likely to have a good or excellent outcome.

      All patients in whom SAH is suspected should undergo a noncontrast head CT. If the CT is normal, a lumbar puncture should be performed in any patient with more than a minimal pretest probability.

Treatment

1. Prevention of rebleeding

   1. The primary treatment of a SAH is to occlude the culprit aneurysm to prevent rebleeding.

   2. This is usually accomplished by deploying platinum coils via arterial catheters within the aneurysm to cause occlusion.

   3. Neurosurgical clipping of aneurysms is now second-line therapy.

2. Prevention of cerebral vasospasm and resulting ischemia

   1. The cause of cerebral vasospasm is poorly understood but is predicted by size of the hemorrhage and loss of consciousness at the time of hemorrhage.

   2. Calcium antagonists, primarily nimodipine, decrease the risk of vasospasm.

3. Management of hydrocephalus

The patient had a thunderclap headache that he describes as the worst headache of his life, which mandates urgent evaluation.

Alternative Diagnoses: Primary Cough Headache, Primary Exertional Headache, & Headache Associated with Sexual Activity

Textbook Presentation

These headaches are primary headaches precipitated by cough, exertion (usually involving the Valsalva maneuver), and sexual activity. They may mimic SAH.

Disease Highlights

1. Cough headaches

   1. Most common in men (≈ 3:1)

   2. More common in older patients (mean age, 67)

   3. Last < 1 minute

2. Exertional headaches

   1. Most common in men (≈ 90%)

   2. Occurs in young people (mean age, 24)

   3. Often bilateral and throbbing

   4. Sometimes related to migraines (some patients may induce migraines with physical activity)

   5. Lasts from 5 minutes to 24 hours

3. Sexual headaches

   1. Also most common in men (≈ 85%)

   2. Mean age, 41

   3. Lasts < 3 hours

   4. Can occur as 3 types

      1. Dull type: dull headache worsening with sexual excitement

      2. Explosive type: SAH-like headache occurring at orgasm

      3. Postural type: postural headache developing after coitus

Evidence-Based Diagnosis

1. Although these headaches may be indistinguishable from more concerning headaches, the clinical presentation can sometimes help identify the diagnosis.

2. They should be considered when the headache starts with cough, sexual activity, or exercise.

3. One review suggested other distinguishing features.

   1. Cough headaches

      1. Either represented the primary headache syndrome or symptoms of an Arnold-Chiari type I malformation in which the cerebellar tonsils protrude out of the base of the skull

      2. Those headaches lasting > 30 minutes were usually secondary to a Chiari type I malformation.

      3. Patients with Chiari type I malformations were younger than those with primary cough headaches (mean age, 39 vs 67).

   2. Sexual headaches

      1. Almost always (93%) benign

      2. In this study, only 1 sexual headache was found to symptomatic of another disease. This headache was caused by a SAH.

      3. Patients with benign sexual headaches tended to have multiple episodes of the headache.

   3. Exertional headaches

      1. Represent either the primary headache syndrome or secondary headaches (causes included SAH and brain tumor).

      2. The primary and secondary headaches were generally indistinguishable.

         Because exertional headaches are clinically indistinguishable from SAH, a patient presenting with such a headache must be carefully evaluated to rule out the latter.

Treatment

1. Cough headaches are effectively treated with cough suppression and NSAIDs.

2. Exertional headaches are treated by avoiding strenuous activity (especially in hot weather or at high altitudes) or by using preexertion ergotamine, beta-blockers, or NSAIDs.

3. Sexual headaches are effectively treated with prophylactic beta-blockers.

Alternative Diagnosis: Benign Thunderclap Headache

Textbook Presentation

The presentation of benign thunderclap headaches is indistinguishable from SAH. The diagnosis is made after normal results are obtained on CT scan and lumbar puncture. These headaches occasionally recur in an unpredictable way.

Disease Highlights

1. Primary headache syndrome

2. Clinically indistinguishable from SAH but lacks any associated neurologic symptoms or signs.

3. Headaches frequently recur over 1–2 weeks and then intermittently over years.

4. In the best study of these headaches:

   1. SAH developed in none of the 71 patients studied.

   2. Headaches generally lasted from 8 to 72 hours.

   3. 51 (72%) of the patients had their headaches unrelated to cough, sexual activity, or exertion.

   4. 17% of the patients had recurrent, similar headaches.

Evidence-Based Diagnosis

1. Benign thunderclap headaches are diagnosed when there is a suspicious clinical presentation and SAH is ruled out.

2. Given the poor prognosis of SAH, CT scan and lumbar puncture should be performed in all patients prior to making this diagnosis.

   Because benign thunderclap headaches are clinically indistinguishable from SAH, they can only be diagnosed after SAH has been ruled out.

Treatment

1. Treatment is challenging because these headaches are short-lived and very intermittent.

2. As-needed analgesics are probably the only reasonable therapy.

Alternative Diagnosis: Intracerebral Hemorrhage

Textbook Presentation

Intracerebral hemorrhage (hemorrhagic stroke) generally presents in older, hypertensive patients with acute-onset headache and focal neurologic symptoms and signs.

Disease Highlights

1. Intracerebral hemorrhage accounts for about 10% of strokes, being less common than embolic and thrombotic strokes.

2. Hypertension is the most common cause, followed by amyloid angiopathy, saccular aneurysm rupture, and arteriovenous malformation rupture.

3. Among patients with hypertension, Asians and blacks have the highest risk of hemorrhagic cerebrovascular accidents.

4. The incidence of hypertension-related intracerebral hemorrhage has declined over the last 3 decades with better control of hypertension.

5. In young patients without hypertension, diseases such as arteriovenous malformation, aneurysm rupture, and drug use should be considered.

6. Arteriovenous malformations are present in 0.01% to 0.05% of the population and usually present in persons between the ages of 20 and 40 years.

   1. Presentation may be with hemorrhage, seizure, or headache.

   2. About 50% of patients with arteriovenous malformation present with a hemorrhagic event. Patients with hypertension or a previous hemorrhage have the highest rate of bleeding.

Evidence-Based Diagnosis

1. Patients with intracerebral hemorrhage usually have headache and focal neurologic signs.

2. A thunderclap-type headache is the presenting sign in nearly 60% of patients.

3. Vomiting is present in about 50% of patients, and seizures are present in about 10%.

4. Noncontrast CT and MRI are equally accurate in making this diagnosis with sensitivities of nearly 100%. MRI may be better at detecting hemorrhagic transformation of ischemic strokes.

Treatment

See the Treatment section under Cerebellar Hemorrhage in Chapter 14, Dizziness.

This patient received the appropriate evaluation. Although he was feeling well at the time of the visit, the test threshold for SAH needs to be very low given the severity of disease. SAH tends to be misdiagnosed in patients with the mildest symptoms. This is because the physician’s suspicion is lowest in these patients and probably because the CT scan may be less sensitive in people with presumably small hemorrhages. Accurate diagnosis of these patients is highly desirable as they potentially have the best outcomes.

With a normal CT scan and lumbar puncture, the diagnosis becomes either benign thunderclap headache or benign exertional headache. The difference is likely semantic, but the headache’s onset and recurrence during exercise makes benign exertional headache the diagnosis. Intracerebral bleed from an arteriovenous malformation was a possibility but was ruled out with the normal CT scan.

This presentation is of concern because the patient is elderly, she has a new headache, and she has experienced weight loss. The differential diagnosis must take into account these pivotal points of age, subacute onset, and constitutional symptoms. The persistence of the headache probably excludes diagnoses such as intracerebral hemorrhage or infections. As we explore the limited differential diagnosis for this patient, the patient’s gender and obesity are important.

Temporal arteritis and malignancy are both possible given the patient’s age and subacute presentation. The throbbing nature of the pain and weight loss could certainly be consistent with either of these types of headache. The history of a breast mass has to make metastatic disease a real consideration. Subdural hematoma is possible, but the lack of a history of head trauma or use of anticoagulation medications makes this less likely. Although a diagnosis of tension headaches should be given with extreme caution in an elderly person with new headaches, the persistent band-like description raises this possibility. A new headache in a woman with obesity also raises the possibility of idiopathic intracranial hypertension. This disease is more commonly seen in young women. Table 20-7 lists the differential diagnosis.

Leading Hypothesis: Temporal Arteritis

Textbook Presentation

Temporal arteritis classically presents in white women over age 50 as a bilateral, throbbing headache. Jaw pain and fatigue with chewing (jaw claudication) may be present. There may be a history of polymyalgia rheumatica or consistent symptoms (shoulder and hip girdle pain) and the physical exam can reveal beading and tenderness of the temporal arteries. The erythrocyte sedimentation rate (ESR) is usually elevated.

Disease Highlights

1. Temporal (or giant cell) arteritis is a corticosteroid-responsive vasculitis of large arteries.

2. Primarily involves the vessels of the aortic arch, particularly the external carotid.

3. Affects people over age 50, women more commonly than men.

4. D. Although the most common presentation is a new headache, temporal arteritis can present with nonspecific manifestations of a chronic inflammatory disorder.

   1. Fever

   2. Anemia

   3. Fatigue

   4. Weight loss

   5. Elevated ESR or C-reactive protein

      Temporal arteritis is in the differential diagnosisfor older people presenting with nonspecific inflammatory conditions.

5. It can also present with specific complications of the disease.

   1. Jaw claudication

   2. Blindness (secondary to ophthalmic artery vasculitis)

6. Related to polymyalgia rheumatica

   1. 15% of patients with polymyalgia rheumatica have temporal arteritis.

   2. As many as 40% of patients with temporal arteritis have polymyalgia rheumatica.

7. Rapid diagnosis and treatment are critical to prevent vasculitis-associated thrombosis in the effected vessels.

Evidence-Based Diagnosis

1. Clinical findings

   1. The clinical signs and symptoms of temporal arteritis are not highly predictive.

   2. Two systematic reviews presented test characteristics for many of the commonly cited findings. These are outlined in Table 20-8.

   3. A few combinations of signs and symptoms have been found to have very high positive LRs.

      1. Headache and jaw claudication: LR+ 8.0

      2. Scalp tenderness and jaw claudication: LR+ 17.0

   4. Reflecting the poor performance of clinical predictors, only 30–40% of patients referred for temporal artery biopsy have the disease.

      Because the clinical signs and symptoms of temporal arteritis are not highly predictive, temporal artery biopsy should be used in any patient in whom the clinical suspicion is even moderate.

2. B. ESR has been used to “rule out” temporal arteritis.

   1. The sensitivity of an abnormal ESR is 96–99%.

   2. The test characteristics of the ESR at various cut points are shown below. (A normal ESR is usually considered to be < age/2 in men and (age + 10)/2 in women.)

      1. Abnormal: LR+, 1.1–1.2; LR–, 0.025–0.2

      2. ESR > 50 mm/h: LR+, 1.2; LR–, 0.35

      3. ESR > 100 mm/h: LR+, 1.9; LR–, 0.8

3. Temporal artery ultrasound

   1. Ultrasound has been used as a diagnostic tool.

   2. Inflamed arteries have a hypoechoic halo around the lumen.

   3. Most studies have found this finding to be insensitive and not specific enough to avoid biopsy.

4. Temporal artery biopsy

   1. Considered the gold standard for diagnosing temporal arteritis.

   2. Given the difficulty of clinically diagnosing temporal arteritis and the common side effects of the treatment, temporal artery biopsy is always recommended to establish the diagnosis of temporal arteritis.

   3. Although biopsy should be done as quickly as possible once the disease is suspected, a short delay after beginning treatment (≈ 7 days) probably does not affect the results.

      Treatment of temporal arteritis should not be delayed to perform a biopsy in a patient in whom temporal arteritis is suspected.

   4. Biopsy of a palpably abnormal artery is the most accurate. If the artery is palpably normal, longer and bilateral biopsies are useful.

   5. There are cases of biopsy-negative temporal arteritis. One much quoted study gave the following test characteristics for temporal artery biopsy:

      1. Sensitivity, 85%; specificity, 100%

      2. LR+, ∞ LR–, 0.15

         Even in the setting of a negative temporal artery biopsy, a patient with very high suspicion for temporal arteritis should be monitored closely or treated.

Treatment

1. The treatment of temporal arteritis is corticosteroids.

   1. Should be started immediately in a patient in whom temporal arteritis is suspected.

   2. Can be tapered slowly once there has been clinical remission as long as the inflammatory markers (ESR, C-reactive protein) remain depressed.

2. Methotrexate might be an option in patients who have recurrent disease upon withdrawal of corticosteroids.

Temporal arteritis certainly remains high on the differential diagnosis. Her headache and physical exam are both suspicious. Assuming a pretest probability of 40% (the usual percentage of positive biopsies among people in whom temporal arteritis is suspected), the prominence of her temporal arteries (LR+ = 2) increases the likelihood of the diagnosis to 57%.

Alternative Diagnosis: Subdural Hematoma

Textbook Presentation

Subdural hematoma is usually seen in older patients with a history of falls and neurologic deterioration. The classic triad of symptoms of chronic subdural hematoma is headache, somnolence, and change in mental status.

Disease Highlights

1. Subdural hematomas may be acute (within 24 hours of injury), subacute (1–14 days after injury), or chronic.

2. Acute and subacute subdural hematomas generally pose little diagnostic problem. They usually produce evolving, focal neurologic deficits.

3. Chronic subdural hematomas can present with subtle symptoms, weeks to months after trauma and can pose a real diagnostic challenge.

4. Chronic subdural hematoma is a disease seen in the elderly and others with cerebral atrophy. Cerebral atrophy allows accommodation of a slowly expanding collection of blood in the subdural space.

5. Risk factors for subdural hematomas are frequent falls, alcoholic dependence, and use of anticoagulant medications such as warfarin or aspirin.

Evidence-Based Diagnosis

1. History and physical exam

   1. Diagnosis requires a high index of suspicion because the presenting symptoms are often subtle.

   2. The mean age at diagnosis is around 70 years in most studies.

   3. The most common presenting symptoms are falls and progressive neurologic deficit.

   4. Head trauma, transient neurologic deficit, seizure, and headache are not uncommon modes of presentation.

   5. The absence of a trauma history should not be particularly reassuring as this history is often hard to establish.

      The most common presenting symptom of chronic subdural hematoma is a history of falls. A high index of suspicion should be present for subdural hematoma in any elderly patient with a history of falls and subacute neurologic deficits.

2. Neuroimaging

   1. CT scan and MRI are both effective means of diagnosing chronic subdural hematoma.

   2. Caution should be used with noncontrast head CT scan because the blood in a chronic subdural hematoma can sometimes be isodense with cortical tissue.

Treatment

Chronic subdural hematomas are treated with surgical drainage unless they are small and asymptomatic.

Alternative Diagnosis: Idiopathic Intracranial Hypertension

Textbook Presentation

Patients tend to be young women who are obese. Headaches caused by idiopathic intracranial hypertension are severe, occur daily, and may awaken the patient from sleep. These types of headaches are associated with transient visual disturbances.

Disease Highlights

1. Idiopathic intracranial hypertension is frequently referred to as pseudotumor cerebri.

2. The characteristics of idiopathic intracranial hypertension were well described from a series of patients in the early 1990s.

   1. The disease tends to effect young (mean age around 30) woman (> 90%)

   2. Sufferers are overwhelmingly obese (94%).

   3. The headaches are usually severe, pulsatile, and often awaken people from sleep.

   4. Visual disturbances (usually lasting only seconds) and pulsatile tinnitus are also common.

3. The presence of papilledema is a very important finding in idiopathic intracranial hypertension. It is present in the overwhelming majority of cases.

4. Idiopathic intracranial hypertension carries the risk of permanent visual loss and must be diagnosed and treated.

Evidence-Based Diagnosis

1. The diagnosis of idiopathic intracranial hypertension is based on recognition of the headache syndrome, diagnosis of increased intracranial pressure, and exclusion of other causes of increased pressure.

2. The headache in idiopathic intracranial hypertension must occur daily, be diffuse and/or constant, or be aggravated by coughing.

3. Intracranial hypertension

   1. Generally first detected on a physical exam by the presence of papilledema, an enlarged blind spot, a visual field defect, or a sixth cranial nerve palsy.

   2. To make the diagnosed, intracranial hypertension must be demonstrated on lumbar puncture (> 200 mm H₂O in nonobese patients, > 250 mm H₂O in obese patients).

   3. Other causes of intracranial hypertension must be excluded.

      1. Neuroimaging (usually an MRI) must be done before the lumbar puncture.

      2. CSF studies must be normal.

      3. Other diseases that can cause intracranial hypertension with a normal MRI need to be excluded (use of growth hormone, tetracyclines, or hypervitaminosis A).

4. The headache must improve after lumbar puncture (with a postprocedure pressure of 120–170 mm H₂O) and resolve after treatment of idiopathic intracranial hypertension.

Treatment

1. Weight loss and carbonic anhydrase inhibitors, which reduce the rate of CSF production) are the mainstay of therapy.

2. Loop diuretics may be use as an adjunctive therapy.

3. Surgical procedures (CSF shunting procedures and optic nerve sheath fenestration) are rarely used for people with refractory disease.

The elevated ESR made the diagnosis of temporal arteritis likely but by no means certain. Taking the pretest probability of 57%, as it stood after the physical exam, an ESR > 100 mm/h raises the probability to 72%. This is probably not high enough to accept the side effects of long-term prednisone therapy without a more definitive diagnosis.

Meningitis

Textbook Presentation

Classically, meningitis presents with the acute onset of the triad of headache, fever, and a stiff neck. Meningitis may occur in the setting of a cluster of cases.

Disease Highlights

1. A. The presentation of fever and headache is common and can be worrisome, potentially caused by anything from influenza to meningitis. The differential includes:

   1. Viral infections and almost any other febrile illness

   2. Meningitis (bacterial, fungal, viral, or parasitic)

   3. Encephalitis

   4. Sinusitis

   5. CNS abscess

   6. Septic cavernous sinus thrombosis

2. Although certainly not the most common cause of fever and headache, meningitis is a relatively common, potentially life-threatening illness.

3. Viral causes are 3–4 times more common than bacterial causes and have a generally favorable prognosis.

4. Bacterial meningitis must be treated as a medical emergency.

5. Mortality rates vary by organism but community-acquired bacterial meningitis has a mortality rate of about 25%.

6. Mortality rates are higher for hospital-acquired infections.

7. The most common organisms are listed in Table 20-9.

Evidence-Based Diagnosis

1. A review studied patients in Holland in whom community-acquired bacterial meningitis was diagnosed over a 3 1/2 year time period; the prevalence of various exam features follow:

   1. 95% of patients had at least 2 of the findings of headache, fever, stiff neck, or mental status changes

      1. 87% had a headache

      2. 83% had stiff neck

      3. 77% had temperature > 38.0°C

      4. 69% had a change in mental status

   2. 33% had focal neurologic findings

   3. 34% of those who had imaging done had an abnormal CT scan

2. Patients with suppressed immune systems and the elderly are less likely to have a stiff neck.

   1. Two of the most commonly used meningeal signs are Kernig (the inability to extend the knee with a flexed hip) and Brudzinski (the demonstration of flexion of both the knees and hips upon forced flexion of the neck).

   2. These signs are present in only about 60% of patients with meningitis.

3. Lumbar puncture

   1. Lumbar puncture is the only means of making a definitive diagnosis.

   2. The CSF in acute bacterial meningitis will demonstrate WBCs with neutrophil predominance, low glucose, and high protein.

4. Patients with contraindications to lumbar puncture

   1. Frequently, the question of contraindication to lumbar puncture is raised.

   2. Performing a lumbar puncture in a patient with a CNS mass, elevated intracranial pressure, or a bleeding diathesis places the patient at risk for complications such as herniation, paraspinal hemorrhage, and death.

   3. CNS imaging should be performed before lumbar puncture in any patient in whom there is a suspicion of increased intracranial pressure.

   4. Findings associated with mass effect on CT scan are

      1. Age > 60 years

      2. Immunocompromise

      3. Preexisting CNS disease

      4. Seizure within the previous week

      5. Abnormal level of consciousness

      6. Inability to answer 2 consecutive questions or follow 2 consecutive commands correctly

      7. Gaze palsy, abnormal visual fields, facial palsy, arm or leg drift, aphasia

         Patients with an abnormal neurologic exam should undergo CNS imaging prior to lumbar puncture.

   5. If CNS imaging is required, a patient with suspected meningitis should have blood cultures drawn and then receive empiric antibiotics immediately, undergo a CT scan, and then have the lumbar puncture.

Treatment

1. As with all infectious diseases, the specific treatment depends on the pathogen.

2. Because of the severity of meningeal infections, empiric therapy is recommended while waiting for Gram stain and culture results.

3. Antibiotic treatment should be ordered when the diagnosis of meningitis is suspected and given immediately after CSF begins to be collected.

4. In adult patients with suspected community-acquired meningitis, the current recommendations are to treat empirically with a third-generation cephalosporin and vancomycin.

5. If Listeria monocytogenes is suspected, ampicillin is also added.

6. Corticosteroids should be added to the regimen in patients with a Glasgow coma scale ≥ 8. (Table 20-10).

Headaches Associated with Head Trauma

Textbook Presentation

A common presentation of a posttraumatic headache would be a middle-aged person who recently suffered head trauma, usually without detectable cranial or neurologic injury, with a headache similar in quality to tension headaches. The headaches are often associated with symptoms such as irritability or anxiety.

Disease Highlights

1. Head trauma can cause serious cranial or neurologic injury including subdural, epidural or parenchymal hematoma, SAH, cerebral contusion, or depressed skull fracture.

2. More commonly, head trauma can cause new headaches or worsen preexisting headache syndromes.

3. Trauma-related headaches might occur after minor or major trauma. The IHS requires 2 of the following to qualify as major trauma:

   1. Loss of consciousness > 30 minutes

   2. 45 minutes of posttraumatic amnesia

   3. Objective measures of cranial or neurologic trauma

4. There appears to be a significant amount of psychiatric distress and disability associated with posttraumatic headaches.

Evidence-Based Diagnosis

1. Acute evaluation of head trauma

   1. In a patient with head trauma or a headache seemingly associated with head trauma, the first goal is to identify important and potentially treatable injury.

   2. The initial test is usually a head CT scan. A difficult question is who can be clinically cleared without a CT scan.

      1. Two clinical decision rules (The Canadian Head CT Rule and the Nexus II).

      2. Nexus II says that if none of the following signs are present, the patient does not need a head CT: Evidence of significant skull fracture, scalp hematoma, neurologic deficit, altered level of alertness, abnormal behavior, coagulopathy, persistent vomiting, age > 65.

      3. The Canadian Head CT Rule is referenced at the end of the chapter.

      4. Both rules have nearly 100% sensitivity for clinically important brain injuries and injuries requiring neurosurgical intervention.

2. Diagnosis of posttraumatic headaches

   1. The next step is to diagnose ongoing headaches as posttraumatic.

   2. The IHS classifies these headaches into headaches following minor or major trauma (see above) and into acute (occurs within 7 days of the injury and resolves within 3 months) or chronic (occurs within 7 days of the injury and does not resolve within 3 months).

   3. Headache develops in about 25% of patients following minor trauma.

      1. These headaches are most likely to be chronic.

      2. They are also most likely to meet criteria for tension-type headaches.

Treatment

1. The treatment of posttraumatic headaches is generally similar to the treatment of clinically similar headaches.

2. It does appear that associated psychological treatment, such as biofeedback and treatment of associated posttraumatic stress syndrome, might be beneficial.