Hemicrania continua

Hemicrania continua is a primary headache disorder which typically affects the side of the head and is continuous. This condition falls under the category of trigeminal autonomic cephalalgias (TACs), a group of headaches that all present unilaterally (on one side only) and which have a mixture of autonomic symptoms distributed along the trigeminal nerve pathway.

The symptoms of hemicrania continua are often non-specific. They mimic other, more common conditions such as migraine (almost 70% of patients present with symptoms that meet the migraine criteria), making diagnosis difficult.

Additionally, other categories of hemicrania continua do not fit in neatly with the diagnostic criteria, notably the remitting subtype.

Symptoms

• Background headache at all times (unlike other TACs, which are episodic)
• There may be exacerbations to this headache sometimes, which can be the presenting symptom
• Pain is usually orbital or retroorbital and can also be frontal, temporal or in another area.

Criteria for diagnosis

• Continuous headache present for >3 months
• Autonomic symptoms, e.g. nasal congestion, eyelid oedema, forehead and facial swelling, miosis, etc., or aggravation of pain by movement or restlessness.
• Responds to indomethacin
• Does not fit the criteria for other headache types.

Differential diagnosis

When seen by a doctor, they may consider alternative diagnoses such as migraine, cluster headache, sinusitis, or other common conditions which can cause headaches. They may order further testing, such as blood tests or imaging. Frequently, however, the diagnosis is made clinically.

Treatment

Hemicrania continua is unique because it can be treated with long-term indomethacin, unlike migraine and cluster headaches.

Prognosis

Hemicrania continua usually responds well to indomethacin treatment. However, indomethacin has gastrointestinal side effects, which can mean some patients do not tolerate it well. Alternative medications may be prescribed if this is the case, and some types of surgery may be a viable option in rare cases.

References

Prakash S, Patel P. Hemicrania continua: clinical review, diagnosis and management. J Pain Res. 2017;10:1493-1509. Published 2017 Jun 29. doi:10.2147/JPR.S128472

The International Classification of Headache Disorders, 3rd edition