Bath-Related Headache: A Case Report

Introduction

Negoro et al. (1) reported a distinctive headache disorder ‘benign hot bath-related headache’ that had never been described before, showing some characteristics: it is induced immediately after starting a hot bath or a hot shower; each headache attack reaches its peak soon after onset; the duration is 10 min to 4 h; it appears as a cluster of headache attacks in a few weeks, disappearing spontaneously; no organic changes are detectable; patients are usually middle-aged women; and its aetiology is not known. After their report of three patients, 10 typical patients (2, 3) and some with variant forms (4) were reported mainly from the Orient. However, there has been no clue to the pathophysiological basis for this type of headache so far. Recently, we saw a woman with benign hot bath-related headache (1) or bath-related headache (BRH) (3). It is interesting that her BRH began in temporal relation with treatment with leuprorelin acetate, a gonadotropin-releasing hormone (Gn-RH) analogue, although the relationship between her BRH and medical oophorectomy was not evident. We describe the patient and discuss possible pathoetiology of BRH.

Case report

A 37-year-old Japanese woman visited us to have a neurological examination because of severe headache attacks. She had no past history of migraine or menstrual headache but had experienced carsickness repeatedly since her childhood. Her mother was a menstrual migraineur. Otherwise, there was no family history of menstrual or hormone-related headaches.

The patient started having monthly injections of leuprorelin acetate (1.88 mg) for 6 months to treat endometriosis. The treatment was successfully finished. During therapy, she had no menstruation. About 1 month after the final injection, she experienced unexpected intense throbbing headache with nausea and vomiting immediately after pouring hot water over the neck to wash her hair. The headache was so severe that her family brought her to an emergency hospital by ambulance. Neurological examination showed no abnormal findings and brain CT was normal. About 4 h from the onset, the headache subsided spontaneously.

Two days later, she felt a sense of discomfort in her neck and shoulders with a foreboding that the severe headache would recur. As soon as she started washing her hair with pouring hot water on her neck, throbbing and tearing headache with nausea appeared. She visited a neurosurgical hospital. Her vital signs were normal with normal blood pressure. Neurological examination was normal without meningeal signs. Lumbar puncture and brain CT revealed no abnormalities. Diclofenac sodium (37.5 mg) was orally administrated. She was not aware that the medication shortened the headache duration or reduced its intensity. Duration of this headache was also about 4 h.

She refrained from washing her hair with hot or cold water after the last episode. Ten days after the first attack, she experienced discomfort just as she had before the second attack of headache. In the evening, however, she began to wash her hair in the way she usually did. Immediately after pouring hot water, the severe headache started and lasted for about 4 h with nausea. The headache subsided with no medication. On the day following the final attack of headache, she was referred to us to have neurological evaluation.

Her body height and weight were 160 cm and 48.5 kg. Physical examination revealed no abnormality with normal blood pressure. Neurological state was also normal. Laboratory findings were normal, including urinalysis, complete blood cell count, screening blood chemistries, serological tests and autoantibodies. Brain MRI revealed her normal brain and a fluid collection in the right maxillary sinus that did not appear to be responsible for her headache on the basis of the otolaryngological examination.

She was told not to have a hot bath or a hot shower when she felt any foreboding symptoms. On the next day, she felt the discomfort and did not have a shower or a bath. Afterwards, there were neither such foreboding feelings nor headache attack. One month after the visit to us, her menstruation resumed. She has been in good health with no recurrence of endometriosis or headache attack.

Discussion

Our patient experienced intense and throbbing headache that was triggered by washing her hair with hot water. The pain built up rapidly to maximum intensity at its onset. Each attack subsided in about 4 h spontaneously. It was repeated three times in 10 days. Thereafter, the headache has never recurred. She had normal neurological examinations, laboratory surveys and brain MR imagings. She had no history of migranous headache although she experienced carsickness and her mother was a migrainuer. All these clinical features are consistent with BRH (1, 3) and our patient was diagnosed as having BRH.

Mak et al. (3) summarized 17 reported cases with bath-related headache (BRH) and divided them into two types: thunderclap headache with hyperacute onset simultaneous with exposure to precipitating factors (type 1 BRH); and moderate or severe headache with gradual onset and after finishing bathing (type 2 BRH). Type 1 BRH presents periodically and remits spontaneously while type 2 BRH is chronic headache and presents recurrently and does not remit spontaneously but can be treated prophylactically. Ravishankar (5) emphasized the difference between the two types of BRH and suggested limiting the usage of the term BRH to just the thunderclap variety. We agree with him because type 2 BRH usually shows chronic migrainous features and in fact has a history of migraine or chronic headache. The clinical picture of our patient indicates that she had an acute thunderclap variant (type 1 BRH). At the same time, she had the carsickness and family history of migraine suggestive of a migrainous variant (type 2 BRH). In addition, she felt a sense of discomfort in her neck and shoulders a few hours before the onset of her headache with a foreboding that the severe headache would recur. It was hard for her to explain this vague feeling precisely. There is a certain similarity to one of the premonitory symptoms that some migraineurs complain of. Our patient suggests possible presence of some overlap between the two types of BRH. The nature of type 1 BRH is sometimes described as throbbing or pulsatile (2, 3) that is suggestive of vascular origin. This could be another example of the overlap. The mechanism of the feeling that our patient presented with needs to be clarified along with the premonitory symptoms observed in some migraineurs. Even though she had a slight inherited predisposition mentioned above and a sign resembling a premonitory symptom in migraine, her headache should be classified into type 1 BRH according to the overall clinical picture.

A distinctive feature of the present patient is that the onset was 1 month after the final injection of the Gn-RH analogue used to treat endometriosis. Gn-RH analogue drives out oestrogen from the ovary and depletes the hormone in it. This phenomenon is called medical oophorectomy. Four weeks after the final injection, serum Gn-RH levels start to decrease with serum oestrogen levels increasing and fluctuating (6, 7). Around this period when our patient was recovering from the medical oophorectomy, she began to have the headache attacks. Unfortunately, we had no substantial clinical data for this patient to show changes in the serum oestrogen level or other hormonal changes other than the 1-month interval between the onset of headache and the final injection of Gn-RH. Gn-RH analogue is reported to be effective in the treatment of menstrual migraine by means of minimizing fluctuations in ovarian hormones (8). It could be speculated that there were rises or fluctuations in oestrogen or progesterone when BRH in our patient started, suggesting a physiological similarity between menstrual migraine and BRH in our case. Although oestrogen withdrawal is the most plausible explanation for the pathophysiology of menstrual migraine, the predominance of evidence indicates that ovarian hormones are similar between menstrual and non-menstrual migraineurs. This would suggest that menstrual migraine is likely to be the result of an abnormal response of the central nervous system to normal fluctuations in ovarian steroids (9). Collecting more pieces of substantial evidence of a similarity or a difference between BRH and menstrual migraine, would give us a better understanding of the mechanisms of the two disorders.

All patients with typical BRH (type 1) are women and the mean age is 51 years (32–67 years) (1–3). The patient with medical oophorectomy might be already in middle age with respect to her hormonal environment although she is the second youngest in the reported cases. Mak et al. (3) reported a 58-year-old woman whose BRH started 3 months after menopause. Other than this and our patients, there was no clear description of such a relationship between BRH and menopause (or menstruation). Although the link may be just coincidental, it is advisable to pay better attention to regression of the pituitary-gonadal axis caused by ageing or medical oophorectomy. Interestingly, all reported cases are from Asia (Japan, Taiwan and Hong Kong). Some ethnic factors also play an important role in the pathogenesis of BRH.