Woman With Short-Lasting, Strictly Unilateral Headaches

THE CASE:

A 47-year-old woman complains of severe headaches that involve only the right orbital, temporal, and occipital areas. She describes the pain as sharp and stabbing, and she rates its severity as 9 or 10 on a 10-point visual analog scale. The headaches last an average of 15 to 30 minutes and usually occur daily. She may have as many as 6 attacks a day; occasionally they also occur at night, waking her. The longer and more severe attacks can be disabling; however, between attacks, she is usually headache-free and functions normally.

The headaches are associated with right-sided lacrimation, nasal congestion, and conjunctival injection. The patient thinks she may also have some associated hypersensitivity to bright light, but she does not have nausea. Except for the unilateral autonomic features of her headache attacks, results of a physical and neurological examination are normal. An MRI scan of the brain, performed 2 weeks earlier, was also normal.

The patient has tried various pain medications, including over-the-counter agents, such as ibuprofen; highly potent prescription painkillers, such as butalbital, codeine, propoxyphene, and hydrocodone; a variety of triptans (sumatriptan, zolmitriptan, frovatriptan, eletriptan, and naratriptan); and most recently, dihydroergotamine mesylate (DHE) nasal spray. She has been hospitalized 3 times in the past 2 years; during each hospitalization, she was treated with intravenous DHE every 8 hours (9 doses total) in combination with various NSAIDs. None of these agents have produced significant and stable positive results.

This patient began having headaches 7 years earlier. At first they occurred on an irregular, infrequent basis, then they gradually worsened. Migraine was diagnosed in the patient's mother when the mother was in her late 20s; the attacks resolved with menopause.

►What is the differential diagnosis of unilateral severe headache with ipsilateral autonomic features?

►Which clinical features are most helpful in pinpointing the diagnosis?

►Is there any effective treatment for this patient's headaches?

THE DIALOGUE:

Primary care doctor: This patient's presentation involves a number of unusual features. Which clinical features suggest a diagnosis?

Headache specialist: The strictly unilateral location of the pain, the autonomic symptoms, and the comparatively brief duration of the pain are the key features here. Although it is usually preferable to look at the entire headache picture, the presence of several unique features prompts consideration of less common headache types that have similar features.¹

Primary care doctor: Which types of headache would you include in the differential diagnosis?

Headache specialist: The following major types of headache are characterized by short duration, strictly unilateral location, and associated autonomic features:

• Cluster headache (and cluster headache variant²).
• Short-lasting unilateral neuralgiform headaches with conjunctival injection and tearing (SUNCT syndrome).
• Chronic or episodic paroxysmal hemicrania.
• Hemicrania continua.

The associated autonomic features can include ipsilateral lacrimation, nasal congestion, ptosis, rhinorrhea, and eyelid edema. Although it is rare to see a patient who presents with all of these autonomic features, at least 1 or 2 should be present in any of the headache types I mentioned.³

Primary care doctor: How can I distinguish among these headache types?

Headache specialist: It is difficult to distinguish one from another because all these disorders share similar autonomic features and all are typically strictly unilateral. (We should note that there is evidence in the literature and from our own clinical experience that occasionally the pain in some of these headache disorders [cluster headaches, paroxysmal hemicrania] can switch sides.⁴The key to the diagnosis is the duration of the acute headache attacks. Although attacks in all of these disorders are comparatively short-lived, the average duration is slightly different in each.Hemicrania continua lasts the longest. Affected patients usually complain of moderate to severe unilateral headache that is almost constant but has fluctuations in severity. Spikes of severe pain may last up to 60 minutes. Patients with this headache type do not consider themselves headache-free between severe episodes, and the headaches persist unless they are responsive to treatment.An acute cluster headache attack can last between 15 minutes and 3 hours. In clinical practice, however, pain typically lasts between 45 minutes and 2 hours. In patients with paroxysmal hemicrania, the head- aches may last from 2 to 30 minutes. In patients with SUNCT syndrome, the headaches last only from 5 seconds to a little over 3 minutes. Typically, in any of these disorders, headaches can occur several times in the same day. In cluster headache, attacks may occur up to 8 times per day; in paroxysmal hemicrania, up to 40 times per day; and in SUNCT syndrome, up to 100 times per day. Except in hemicrania continua, patients are usually headache-free between attacks.

Primary care doctor: My patient's headaches last between 15 and 30 minutes and can occur multiple times per day. Thus, her symptoms most closely approximate those of paroxysmal hemicrania. How common is this disorder?

Headache specialist: Paroxysmal hemicrania is considered rare: only a few more than 100 cases have been described in the literature.

Primary care doctor: If it is so rare, why is it important to be able to identify this particular headache disorder?

Headache specialist: First, I strongly believe that the prevalence of paroxysmal hemicrania is underestimated; I suspect this disorder is often misdiagnosed as cluster headache or even migraine. Second, even though it is much rarer than migraine, tension-type headache, or cluster headache, paroxysmal hemicrania usually involves multiple attacks per day and thus causes the patient significant disability. Finally, its diagnosis points to a specific and usually effective treatment strategy, thereby obviating the need to try other ineffective medications.⁵ In fact, the treatment of paroxysmal hemicrania is quite simple and produces a powerful response that significantly reduces patient disability.

Primary care doctor: Perhaps lack of a correct diagnosis explains why this patient has tried multiple medications and treatment strategies, including inpatient treatment, without success? Headache specialist: Yes, this case clearly illustrates how difficulty in arriving at the correct diagnosis can waste time, prolong a patient's disability, and frustrate patient and clinician alike. All standard treatment modalities had been tried in this woman, including highly potent triptans and ergots. Unfortunately, none of these medications has demonstrated efficacy in the management of paroxysmal hemicrania.Indomethacin is the single medication that has proved effective in this setting.⁶ The response to this medication is uniformly dramatic. As such, experts have suggested that a positive response to indomethacin be included in the diagnostic criteria for paroxysmal hemicrania. If a patient with possible paroxysmal hemicrania does not respond to indomethacin, this diagnosis should be reconsidered.

Primary care doctor: What dosage of indomethacin is recommended in patients with paroxysmal hemicrania, and what is the duration of treatment?

Headache specialist: Start with 25 mg tid. At the end of 1 week, the dosage may be increased to 50 mg tid. Anticipate a positive response by the second or third day of treatment. Once an adequate response has been achieved, you may switch to a maintenance dosage of between 25 and 100 mg/d.The goal of indomethacin therapy is long-lasting remission. Once this goal is reached, consider gradually tapering the dosage. Exercise caution when chronic indomethacin treatment is required; GI side effects may develop, and these must be addressed promptly and appropriately.