Intranasal lidocaine, somatostatin by infusion, and subcutaneous octreotide are considered second-line treatment choices for patients who are resistant to first-line therapies or who cannot tolerate them.14,35,43,44
Cluster Headache Prophylaxis
A CH period can last for weeks to months. Prophylactic modalities, which are intended to shorten this period and to reduce the frequency and severity of headache attacks, are categorized into transitional and maintenance prophylaxis treatments.14,35
Transitional prophylaxis, a shorter course of treatment, is often started with maintenance prophylaxis (which is used throughout each cluster period) to hasten the response to the maintenance treatment. Corticosteroids are commonly used as a transitional treatment modality. In prednisone use, a starting dose of at least 40 mg/d by mouth is often required to provide benefit.14 The peak dose is usually given for three to 10 days, then gradually tapered over the succeeding 10 to 30 days. Headache recurrence is common during the prednisone taper. Ergotamine tartrate and DHE are also used as transitional prophylaxis treatment for CH.14
Verapamil is considered the maintenance prophylaxis drug of choice due to its efficacy and safety.14,35,45 The dosage required for adequate response ranges from 200 mg to 960 mg/d, in divided doses or in extended-release formulation. Most patients respond to daily doses between 200 mg and 480 mg.14,46,47 Constipation is the most common adverse effect. Slow titration and frequent ECG monitoring, particularly when dosing is increased, are necessary to avoid heart block, bradycardia, hypotension, and peripheral edema.13
Lithium is often used as second-line therapy for maintenance prophylaxis, possibly in combination with verapamil or topiramate, to improve pain control.35 Lithium carbonate, given at a dosage of 600 to 900 mg/d to maintain a serum level of 0.4 to 0.8 mEq/L, and topiramate, at dosages ranging from 50 to 200 mg/d, may be needed to achieve an adequate response.14
In at least one small study, melatonin (10 mg/d) has been associated with CH remission in 50% of treated patients.14,48 It may be used in combination with other prophylactic medications.14
Among numerous other agents that have been used for CH prophylaxis, neither sodium valproate, sumatriptan, cimetidine/chlorpheniramine, misoprostol, nor oxygen is recommended for prevention of CH.35
Narcotics
Because of its excruciating pain, CH has been referred to as “suicide headache.”2,6,7,10,13 Acute and prophylactic treatments for CH will likely reduce the number of headache attacks; however, with CH attacks as frequent as eight times per day, these treatments may not be adequate.24,49
The use of any narcotic is not ideal due to its potential for addiction, and it may cause medication-overuse headache. Furthermore, in oral form, a narcotic may not relieve CH pain quickly enough. Low-dose levomethadone is an opioid that has been used prophylactically with some success in patients with chronic CH.24,49 However, the primary care provider whose CH patient finds pain control inadequate should refer to a neurologist or a pain management specialist for evaluation—and possibly for treatment with an invasive procedure.
Invasive Procedures
Greater occipital nerve block has shown promise in the treatment of CH.50,51 In a small, double-blind study, patients with episodic or chronic CH were randomized to receive a suboccipital injection, of either combined long- and rapid-acting betamethasone or saline (placebo), in the area of the greater occipital nerve.50 Eighty-five percent of treated patients were free of headache attacks within 72 hours, compared with none in the control group. Use of lidocaine with triamcinolone was found somewhat less effective.51
Occipital nerve stimulation has also shown promise for patients with chronic CH who become resistant or are unresponsive to conventional treatments, or who cannot tolerate them.14,24 It appears to induce gradual neuromodulation, with gradual benefits (after six to 30 months). Deep brain stimulation (ie, of the posterior hypothalamus), delivered via implanted electrodes, and other procedures have produced results ranging from “excellent” to “transient remission,” reducing the use of ablative surgeries.14,52 Because invasive modalities carry a risk for serious adverse effects,14 their use should be reserved for a select patient population.
PATIENT/FAMILY EDUCATION
Patients with CH need to be educated regarding the nature, signs and symptoms, and triggers of CH. The indications for acute and prophylactic treatments and the adverse effects associated with each therapy must also be reviewed. Clear follow-up instructions are essential, including what conditions warrant further evaluation: worsening of the condition, changes in symptoms (impaired alertness, vision, movement, or sensation; onset of seizures), or treatment failure.
CONCLUSION
Cluster headache, a relatively uncommon primary headache that can cause excruciating and debilitating pain, is often misdiagnosed and inappropriately treated, with serious physical, social, and economic ramifications. This headache type is unilateral, associated with autonomic symptoms, and characterized by clustering of headache/remission periods in a circannual and/or circadian pattern. Diagnosis is made through the health history and physical exam, based on criteria from the ICHD-II. Neuroimaging may not be necessary, but given the evidence that CH and TAC are often associated with serious underlying pathology, MRI with contrast should be considered, and consultation with a neurologist at initial diagnosis is recommended.