MIGRAINE HEADACHE: ESSENTIALS OF DIAGNOSIS AND CLINICAL PRESENTATION

Migraine headache is a common disorder that affects approximately 6% of men and 17% of women, usually at the peak of their productivity.¹ According to the American Migraine Study, most patients with migraine do not seek medical care for their headaches.² Still, a significant number of them present to physician’s offices, particularly in the primary care setting. An accurate diagnosis of migraine should lead to an effective therapeutic strategy, reduce disability, and improve productivity in these patients. This newsletter provides a practical yet comprehensive approach that should help clinicians correctly recognize and identify migraine headaches.

PATIENT HISTORY

Information from the clinical history is the cornerstone of formulating a differential diagnosis, and migraine is not an exception. Most individuals seeking medical care for their headaches suffer from migraine.³ This initial evaluation should serve to promptly and reliably identify the salient features of migraine while, at the same time, detect the red flags of a secondary headache. These red flags are often called the SNOOP features. The author has adapted them as follows:

Systemic symptoms (eg, fever, weight loss)

Neurologic symptoms or abnormal signs (eg, confusion, impaired alertness)

Onset (ie, sudden, abrupt, or split-second)

Older (ie, new onset of progressive headache in patients >50 y [eg, giant cell arteritis])

Previous headache history (ie, first headache or new or different headache; change in attack frequency, severity, or clinical features)

Secondary risk factors (eg, HIV infection, systemic cancer)

In the author’s own clinical practice, patients are required to complete a headache questionnaire prior to their clinic encounter. The questionnaire is designed to characterize and rule in the salient features of a migraine headache and can include questions about the duration of the headache syndrome, individual attacks, frequency of attacks, quality and location of the pain, associated symptoms, triggering factors, relieving factors, pharmacological history (including frequency of use of individual abortive agents and prior use of prophylactic agents), family history, and comorbidities (eg, insomnia, anxiety, depression). By reviewing such a questionnaire prior to the actual patient encounter, the clinician can have a well-formed idea of the salient features of that patient’s headache disorder. Outlier responses in this questionnaire help to identify the red flags of secondary headaches or unusual primary headache syndromes, such as cluster headache or the paroxysmal hemicranias. The actual patient interview may serve to clarify or elaborate on the answers on the questionnaire.

Prodromal symptoms and aura

The migraine prodrome comprises the symptoms (eg, yawning; food cravings; changes in sleep, appetite, or mood) that precede the headache phase by hours or days. Aura precedes the headache phase by minutes and it may or may not persist during it. Aura is more often visual (eg, scotomata or positive visual phenomena such as teichopsia, photopsia, or dysmorphopsia). Sensory aura is less common; it is characterized by paresthesias in the upper extremity and perioral area (ie, cheiro-oral paresthesias). Motor and language deficits are less common. The migraine prodrome does not occur in all patients, and a history of aura is present in only about 20% of cases.⁴

Frequency, quality, location, and duration of the headache

The questionnaire inquires about total number of days with any degree of headache per month (headache days) as well as number of days with an incapacitating headache. Migraine pain is typically pulsatile or throbbing in quality and unilateral or bilateral in location. It is typically temporal, but it may be perceived as frontal, parietal, or occipital. The headache phase may last anywhere from 3-72 hours. Patients with chronic (also called transformed) migraine may report a dull, more diffuse and persistent headache in between attacks of more typical migraine pain.

Other features of the headache

Migraine headache is often accompanied by nausea, sometimes with emesis. Sensitivity to light and sound are common symptoms. Patients often seek rest, and the headache is made worse by physical activity or head movement. Allodynia or skin hypersensitivity in cranial or extracranial areas is a commonly reported symptom of prolonged headache attacks.⁵

Trigger factors

A fraction of migraine patients are able to identify environmental, dietary, or intrinsic factors, such as hormonal fluctuations or disruption of sleep habits, as triggers for an attack of migraine headache.

Family history

Migraine is often a familial disorder. A positive family history of recurrent disabling headache serves as additional evidence in favor of migraine when formulating the differential diagnosis.

HIGHLIGHTS OF THE PHYSICAL AND NEUROLOGICAL EXAMINATIONS

The physical examination of the headache patient should be comprehensive yet focus on relevant systems and organs. Palpation of the skull, scalp, and temporomandibular joints (TMJ) for localized tenderness, crepitus, or vascular induration and tenderness should be performed initially. The physician should assess the range of motion of the cervical spine and palpate for spasm of the paracervical musculature.⁶ In some situations, such as in acute sinusitis or periodontal disease, examination of the nasal and oral cavities must be undertaken.

A thorough funduscopic examination should be performed on all patients reporting headache. This examination should not be limited to visualization of the optic disk margins and should include determination of retinal venous pulsations, arteriovenous crossings, and the presence of hemorrhages. A general physical examination may elicit pertinent findings in some cases. For example, a midsystolic click on cardiac auscultation of female patients with migraine and mitral valve prolapse is a commonly found comorbidity in this group of patients.⁶

Finally, a thorough neurological examination must be performed to screen for structural etiologies for the headache. The physician should concentrate on the detection of signs of cognitive dysfunction; reduced visual acuity or field defects; or asymmetries in the motor, sensory, coordination, and reflex examinations. Rarely, structural lesions may present with localized low-grade headache and a paucity of abnormal findings in the neurological examination. Fortunately, in most cases, a thorough history and careful physical and neurological examinations are sufficient to rule out or rule in organic etiologies for the headache, thus reducing the need for costly neuroimaging studies.⁷

SCREENING INSTRUMENTS: THE ID MIGRAINE QUESTIONNAIRE

In addition to provider-specific questionnaires as described previously in this newsletter, several widely available and validated short screening tools can also be useful in the identification of migraine headache in the primary care setting. The ID Migraine screening questionnaire (developed by Pfizer, Inc.) is a self-administered test that may be completed by patients while they are sitting in the waiting room.⁸ The questions on the ID Migraine screening questionnaire are as follows:

1. Has a headache limited your activities for at least 1 day in the last 3 months?

2 .Are you nauseated or sick to your stomach when you have a headache?

3. Does light bother you when you have a headache?

Patients who have an affirmative answer to 2 or more of the questions have a high probability (93.3%) of having migraine. This questionnaire has a sensitivity of 81% and a specificity of 75%. This simple instrument can be easily incorporated into the interview or into information management systems.⁸

REFERENCES

1. Lipton RB, Stewart WF. Migraine in the United States: a review of epidemiology and health care use. Neurology. 1993;43(Suppl 3):S6-10.

2. Lipton RB, Stewart WF, Simon D. Medical consultation for migraine: results from the American Migraine Study. Headache. 1998;38:87-96.

3. Mendizabal JE. A practical approach to migraine headache. Compr Ther. 2000;26(4):263-8.

4. Silberstein SD, Young WB. Migraine aura and prodrome. Semin Neurol. 1995;15:175-82.

5. Yarnitsky D, Goor-Aryeh I, Bajwa ZH, et al. 2003 Wolff Award: Possible parasympathetic contributions to peripheral and central sensitization during migraine. Headache. 2004;44(5):447.

6. Mendizabal JE. Interviewing and examining the headache patient. Int Med. 1999;20:12-19.

7. Ramirez-Lassepas M, Espinosa CE, Cicero JJ, et al. Predictors of intracranial pathologic findings in patients who seek emergency care because of headache. Arch Neurol. 1997;54(12):1506-9.

8. Lipton RB, Dodick D, Sadovsky R, et al. A self-administered screener for migraine in primary care: the ID Migraine validation study. Neurology. 2003;61:375-82.