Definition and Overview
Cluster headaches are the most common and severe form of trigeminal autonomic cephalalgias (TACs). Severe pain around one eye, behind the eye socket, temporal area, or forehead lasts for 15 minutes to 3 hours, and is accompanied by one or more autonomic symptoms on the ipsilateral side, such as lacrimation, conjunctival injection, nasal congestion or runny nose, ptosis, miosis, eyelid edema, and forehead sweat.
Because the pain intensity is so extreme, it is also called a “suicide headache.” The prevalence rate is about 1 per 1,000 people, which is not uncommon, and is about 3 times more common in men than in women.
Classification
Cluster headaches are classified according to the pattern of cluster periods and remission periods as follows.
- Episodic cluster headache: Cluster periods lasting 7 days to 1 year followed by remission periods of 3 months or more. It accounts for approximately 85-90% of all patients.
- Chronic cluster headache: Attacks last for more than a year without relief for more than three months. It is about 10-15% of the total.
Causes and Mechanisms
Trigeminal nerve-autonomic reflexes
The core mechanism of cluster headache is trigeminal nerve activation and the resulting parasympathetic nerve reflex. When the trigeminal nerve is activated, neuropeptides such as CGRP (calcitonin gene-related peptide) and vasoactive intestinal peptide (VIP) are released from meningeal blood vessels, causing vasodilation and inflammation.
Hypothalamic involvement
Functional MRI studies show activation of the posterior hypothalamic gray matter during attacks. This explains the temporal periodicity (circadian pattern, seasonality) of headaches and is a target for deep brain stimulation (DBS).
symptoms
headache attack
- Attack duration: 15 minutes to 3 hours (average 45 to 90 minutes)
- Attack frequency: 1 to 8 times per day, repeated during cluster periods.
- Pain pattern: extreme stabbing pain, burning pain
- When it occurs: Commonly occurs 1 to 2 hours after nighttime sleep; Seasonally, cluster periods often begin in spring and fall.
- Agitation during an attack: Unlike a migraine, the person cannot remain still during the attack and paces or shakes the body.
Autonomic symptoms (ipsilateral)
Excessive lacrimation, conjunctival injection, nasal congestion or runny nose, ptosis, miosis, and forehead or facial sweating may occur ipsilaterally during the attack.
diagnosis
The diagnosis of cluster headache is a clinical diagnosis according to the International Headache Society (IHS) classification criteria (ICHD-3). Assess headache location, duration, accompanying autonomic symptoms, and cluster pattern.
It is recommended to perform brain MRI and cerebrovascular MRA examination early in the diagnosis to rule out secondary causes (brain aneurysm, brain tumor).
treatment
acute care
Because the duration of cluster headache attacks is short, oral medications have limited effectiveness, and the following treatments are prioritized.
- High-flow oxygen inhalation: Most often mask inhalation of 7 to 12 liters of oxygen per minute for 15 minutes. Studies have shown that approximately 78% of patients reported improvement in pain within 15 minutes.
- Sumatriptan subcutaneous injection (6mg): It is a fast-acting and proven acute treatment.
- Sumatriptan nasal spray and zolmitriptan nasal spray are also used.
preventive care
During the cluster period, preventive treatment is administered to reduce the frequency of attacks.
- Verapamil: The most well-evidenced preventive drug. Use under electrocardiogram monitoring.
- Short-term prevention: Rapidly suppresses attacks with a short course of prednisolone in the early stages of an attack.
- Lithium: Useful for chronic cluster headaches
- Galcanezumab (anti-CGRP antibody injection): reported to be effective in preventing episodic cluster headaches
neuromodulation treatment
Non-invasive vagus nerve stimulation is used as an adjunct to acute and preventive treatment. A case in which hypothalamic deep brain stimulation (DBS) was performed for intractable chronic cluster headache has been reported.