Cluster headache, like migraine, is a primary headache. However, cluster headache is also very different from migraine. It affects more men than women – for migraines, it is the other way round. It manifests as relatively short (15 min to 3 hours) pain attacks always on the same side of the head. For comparison, migraine attacks last between 4 hours and 3 days.
The “suicide headache”
The most important difference is the severity of the attacks. Migraines can be severe, confining the patient to bed and making it impossible to perform tasks of the day. However, oftentimes, cluster headache attacks are not only severe, but excruciating. Therefore, cluster headaches are sometimes also described as “suicide headaches”. Many patients have the desire to bang their head against the wall during cluster headache attacks, and some will do so. In addition to this, patients can have several cluster headache attacks per day, and even worse, at night. We have been treating cluster headache patients for 15 years, and have always thought that they need our care and treatment even more than migraine patients do.
Too little research
However, cluster headaches are not as well-known as migraines. This is because they are much less prevalent, affecting about 0.1% of the population. Migraines affect about 10%.
Being affected by a rare disorder comes with a lot of disadvantages. Years may pass before finding a doctor who makes the correct diagnosis. There is less research, and consequently less knowledge on pathophysiology and effective treatments. There are also less tools for quantifying the disorder and its impact on the patients’ lives.
Number of attacks is only part of the picture
Assessing the impact of a disorder on the patients’ daily life is important for understanding the associated disability. In headache and pain disorders, we now know that assessing pain intensity, duration, frequency of attacks and intake of medication is only part of the picture. The other part is assessing the impact on patients’ lives.
There is a wealth of questionnaires to assess migraine-related disabilities. Two of them, the Headache Impact Test (HIT-6) and the MIDAS (Migraine Disability Assessment Score) are among the most used both in clinical routine and research, because they are short, self-rated, and easily performed and scored. Such a questionnaire has been lacking for cluster headaches.
Development of the Cluster Headache Impact Questionnaire (CHIQ)
This is a gap that we aimed to close with the development and validation of the Cluster Headache Impact Questionnaire (CHIQ) that has now been published in The Journal of Headache and Pain.
We developed an 8-item questionnaire, that poses not only general questions like “How much have your headaches limited your ability to work” but also includes cluster headache-specific problems like sleep deprivation due to nocturnal attacks and self-harming behaviour during attacks.
We asked 254 patients to fill the CHIQ and other, related questionnaires. We successfully performed the usual steps to assess reliability and validity of the CHIQ. We found a good correlation between CHIQ scores and number of attacks per week, but also patients currently in remission (attack-free) had CHIQ scores above 0, showing that the impact of cluster headaches does not end when the attacks stop. This makes sense because most cluster headache patients suffer from a relapsing-remitting form called, episodic cluster headache. Therefore, the fear of relapsing, significantly contributes to disability.
Correlations of CHIQ scores with depression, anxiety, and quality of life corroborate that the impact of cluster headaches relates to these aspects, too. Comparison with a generic headache impact questionnaire (HIT-6) showed that the CHIQ is superior for assessing cluster headache related disability.
Cluster headache patients urgently need more attention drawn to their disorder. We developed the CHIQ hoping that it will contribute to both, improving clinical care for cluster headache patients and promoting cluster headache research.
Dr. Ruth Ruscheweyh is a resident at the Department of Neurology of the Ludwig Maximilians University hospital in Munich, Germany. She is the head of the Headache Registry of the German Migraine and Headache Society. Her research interests are patient-reported outcomes and psychological factors in headache and pain on the one hand, and calcitonin gene-related peptide (CGRP) and descending pain inhibition on the other.
Dr. Katharina Kamm is a resident at the Department of Neurology of the LMU University Hospital and at the Upper Bavarian Headache Center of the LMU University Hospital Munich, Germany. Her research focuses on primary headache disorders. In this respect, she is especially interested in cluster headache as well as the role of calcitonin gene-related peptide in migraine and cluster headache.