American Board of Internal Medicine (ABIM) Certification Practice Exam

Which treatment is considered most effective for acute cluster headaches?

1. Subcutaneous sumatriptan

2. Oxygen therapy

3. Ibuprofen

4. Topiramate

The correct answer is: Oxygen therapy

Oxygen therapy is recognized as one of the most effective treatments for acute cluster headaches. The mechanism involves the administration of 100% oxygen at a flow rate of 7-15 liters per minute for about 15-20 minutes, which has been shown to alleviate the severe pain associated with acute attacks. It helps by inducing vasoconstriction of the dilated cerebral vessels and possibly reducing inflammation. Cluster headaches are characterized by their sudden onset and intense, throbbing pain, often around one eye, and they typically occur in cyclical patterns or "clusters." Because of their unique nature, traditional pain relievers like ibuprofen are not nearly as effective in treating these types of headaches. Preventive medications such as topiramate might be useful in reducing the frequency of attacks but do not offer immediate relief during acute episodes, making them less suitable for the acute phase of a cluster headache. Subcutaneous sumatriptan is another effective treatment for acute cluster headaches, providing relief for some patients; however, studies and clinical practice have shown that oxygen therapy is generally faster and more effective in treating an active attack. For individuals who cannot tolerate, or prefer not to use, pharmaceutical treatments, oxygen therapy provides an excellent alternative option.