Laugh-Induced Headache: Clinical Features and Literature Review

BACKGROUND

Laughing is a rare precipitating factor for headaches, and the pathogenesis underlying laugh-induced headache (LH) remains unclear.

METHODS

Two cases of headache triggered predominantly by laughing were presented in this article. We also reviewed the published English literature regarding LH, summarized the clinical characteristics of LH, and discussed the probable pathophysiological mechanisms.

RESULTS

In the first patient, magnetic resonance imaging of the brain revealed cerebellar tonsillar herniation through the foramen magnum. In the second patient, we did not find any evidence of intracranial disease. The literature review showed that LH is a mild to severe, non-pulsating headache. In most cases, the duration of each attack was limited to a few minutes. The headache usually bursts after laughing and reaches its peak almost immediately. In some cases, the headache can only be induced by mirthful laughing rather than by fake laughing.

CONCLUSION

LH can be categorized as primary LH and secondary LH. Changes in the spatial structure in the posterior cranial fossa and cerebrospinal fluid circulation may contribute to the development of secondary LH. Primary LH, primary cough headache, and primary exercise headache may share some common pathogenesis. And we speculate that the regions of the brain associated with the expression of mirth might be associated with LH.

The Frequent Unusual Headache Syndromes: A Proposed Classification Based on Lifetime Prevalence

BACKGROUND

There is no agreement on a single cutoff point or prevalence for regarding a given disease as rare. The concept of what is a rare headache disorder is even less clear and the spectrum from a very frequent, frequent, occasional to rare headache syndrome is yet to be established.

OBJECTIVE

An attempt has been made to estimate the lifetime prevalence of each of the headache subtypes classified in the ICHD-II.

METHOD

Using the ICHD-II, 199 different headache subtypes were identified. The following classification was made according to the estimated lifetime prevalence of each headache disorder: very frequent (prevalence >10%); frequent (between 1 and 10%); occasional (between 0.07 and 1%); and unusual or rare (<0.07%).

RESULTS

One hundred and fifty-four of 199 (77%) were categorized as unusual headache disorders, 7/199 (4%) as very frequent, 9/199 (5%) as frequent, and 29/199 (15%) as occasional forms of headache disorder.

CONCLUSION

The unusual headache syndromes do not appear to be as infrequent in clinical practice as has been generally believed. About three-fourths of the classified headache disorders found in the ICHD-II can be considered as rare. This narrative review article may be regarded as an introduction to the concept of unusual headaches and a proposed classification of all headaches (at least those listed in the ICHD-II).