A 45-year old man presents with a daily headache. He describes two attacks per day over the past 3 weeks. Each attack lasts about an hour and awakens the patient from sleep. The patient has noted associated tearing and reddening of his right eye as well as nasal stuffiness. The pain is deep, excruciating, and limited to the right side of the head. The neurologic examination is nonfocal. The most likely diagnosis of this patient’s headache is –

## **Core Concept**
The patient's symptoms suggest a type of headache disorder characterized by recurrent, severe, unilateral headaches, often accompanied by autonomic symptoms such as tearing, reddening of the eye, and nasal stuffiness. This presentation is classic for a specific primary headache disorder.

## **Why the Correct Answer is Right**
The correct answer, **Cluster Headache**, is a type of primary headache disorder that fits the patient's presentation. Cluster headaches are characterized by:
- Severe, unilateral orbital, supraorbital, or temporal pain lasting 15 to 180 minutes
- Recurrent attacks occurring in clusters or periods
- Associated autonomic symptoms such as conjunctival injection, lacrimation (tearing), nasal congestion, or rhinorrhea on the same side as the headache
- The headaches often occur at the same time each day and can awaken the patient from sleep

## **Why Each Wrong Option is Incorrect**
- **Option A: Migraine** - While migraines can be severe and unilateral, they typically last longer (hours to days) and are often accompanied by nausea, vomiting, and photophobia or phonophobia, which were not mentioned in the scenario.
- **Option B: Tension-Type Headache** - Tension-type headaches are usually bilateral, of mild to moderate intensity, and not associated with autonomic symptoms like tearing and nasal stuffiness.
- **Option D: Trigeminal Neuralgia** - Trigeminal neuralgia involves brief, shock-like or stabbing pain in one of the divisions of the trigeminal nerve, without the autonomic features described.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that cluster headaches are sometimes referred to as "suicide headaches" due to their extreme severity. They are also notable for their periodicity, with some patients experiencing remission for months or years between clusters. Treatment often involves acute therapies like oxygen therapy and preventive treatments to reduce cluster period frequency and headache frequency.

## **Correct Answer: C. Cluster Headache**

✓ Correct Answer: B. Cluster headache