**Question:** An attack of cluster headache can be aborted by

A. oxygen therapy
B. ergotamine-containing medications
C. corticosteroids
D. sumatriptan

**Core Concept:** Cluster headache is a severe primary headache disorder characterized by recurrent, short-lasting attacks of severe pain around the eye or temple. These attacks often occur in clusters or cycles, and can be triggered by various factors.

**Why the Correct Answer is Right:** Among the given options, oxygen therapy (Option A) is the most effective intervention for aborting a cluster headache attack. Oxygen therapy is thought to provide relief by increasing the availability of nitric oxide, which in turn dilates blood vessels and reduces the severity of the headache.

**Why Each Wrong Option is Incorrect:**

B. Ergotamine-containing medications (Option B) are primarily used for prevention of cluster headache attacks, not for aborting active attacks. They work by constricting blood vessels and reducing migraine triggers.

C. Corticosteroids (Option C) are used for the prevention of cluster headache attacks but are generally not effective for aborting an ongoing attack. They help to reduce inflammation and prevent headache onset.

D. Sumatriptan (Option D) is a triptan drug used for aborting migraine attacks, not cluster headache attacks. Triptans work by selectively binding to serotonin receptors in the brain, constricting blood vessels and reducing migraine pain.

**Clinical Pearl:** Cluster headache patients often experience significant relief with oxygen therapy, which should be considered as a first-line treatment for aborting an active attack. However, prevention strategies, including medications like lithium, verapamil, and corticosteroids, are essential for managing cluster headache over the long term.

**Correct Answer:** A. Oxygen therapy

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Cluster headaches are severe primary headaches that can significantly impact patients' quality of life. Oxygen therapy is a well-established treatment for aborting an active cluster headache attack. Understanding the underlying pathophysiology of cluster headaches can help to appreciate the mechanisms of action of the correct answer, oxygen therapy. In cluster headaches, the increased availability of nitric oxide is believed to contribute to the severe pain experienced during an attack. Oxygen therapy increases the availability of nitric oxide, thereby dilating blood vessels and reducing headache severity. In contrast, ergotamine-containing medications, corticosteroids, and sumatriptan are used for prevention and treatment of migraines, not cluster headaches. These medications work through different mechanisms, such as constricting blood vessels and reducing inflammation, which do not apply to cluster headaches.