Melatonin in hemicrania continua and paroxysmal hemicrania.

BACKGROUND: Hemicrania continua (HC) and paroxysmal hemicrania (PH) belong to a group of primary headache disorders called trigeminal autonomic cephalalgias. One of the diagnostic criteria for both HC and PH is the absolute response to the therapeutic dose of indomethacin. However, indomethacin is discontinued in many patients as a result of intolerance to its side effects. Melatonin, a pineal hormone, which shares similar chemical structure to indomethacin, has been reported to have some efficacy for HC in previous case reports and series. To our knowledge, there is no literature regarding the use of melatonin in PH. We aimed to describe the clinical use of melatonin in the preventive management of HC and PH. METHODS: Patient level data were extracted as an audit from routinely collected clinical records in consecutive patients seen in outpatient neurology clinic at King's College Hospital, London, UK, from September 2014 to April 2023. Our cohort of patients were identified through a search using the keywords: hemicrania continua, paroxysmal hemicrania, melatonin and indomethacin. Descriptive statistics including absolute and relative frequencies, mean ± SD, median and interquartile range (IQR) were used. RESULTS: Fifty-six HC patients were included with a mean ± SD age of 52 ± 16 years; 43 of 56 (77%) patients were female. Melatonin was taken by 23 (41%) patients. Of these 23 patients, 19 (83%) stopped indomethacin because of different side effects. The doses of melatonin used ranged from 0.5 mg to 21 mg, with a median dose of 10 mg (IQR = 6-13 mg). Fourteen (61%) patients reported positive relief for headache, whereas the remaining nine (39%) patients reported no headache preventive effect. None of the patients reported that they were completely pain free. Two patients continued indomethacin and melatonin concurrently for better symptom relief. Eight patients continued melatonin as the single preventive treatment. Side effects from melatonin were rare. Twenty-two PH patients were included with mean ± SD age of 50 ± 17 years; 17 of 22 (77%) patients were female. Melatonin was given to six (27%) patients. The median dose of melatonin used was 8 mg (IQR = 6-10 mg). Three (50%) patients responded to melatonin treatment. One of them used melatonin as adjunctive treatment with indomethacin. CONCLUSIONS: Melatonin showed some efficacy in the treatment of HC and PH with a well-tolerated side effect profile. It does not have the same absolute responsiveness as indomethacin, at the doses used, although it does offer a well-tolerated option that can have significant ameliorating effects in a substantial cohort of patients.

Mitochondrial diseases in Hong Kong: prevalence, clinical characteristics and genetic landscape.

OBJECTIVE: To determine the prevalence of mitochondrial diseases (MD) in Hong Kong (HK) and to evaluate the clinical characteristics and genetic landscape of MD patients in the region. METHODS: This study retrospectively reviewed the phenotypic and molecular characteristics of MD patients from participating public hospitals in HK between January 1985 to October 2020. Molecularly and/or enzymatically confirmed MD cases of any age were recruited via the Clinical Analysis and Reporting System (CDARS) using relevant keywords and/or International Classification of Disease (ICD) codes under the HK Hospital Authority or through the personal recollection of treating clinicians among the investigators. RESULTS: A total of 119 MD patients were recruited and analyzed in the study. The point prevalence of MD in HK was 1.02 in 100,000 people (95% confidence interval 0.81-1.28 in 100,000). 110 patients had molecularly proven MD and the other nine were diagnosed by OXPHOS enzymology analysis or mitochondrial DNA depletion analysis with unknown molecular basis. Pathogenic variants in the mitochondrial genome (72 patients) were more prevalent than those in the nuclear genome (38 patients) in our cohort. The most commonly involved organ system at disease onset was the neurological system, in which developmental delay, seizures or epilepsy, and stroke-like episodes were the most frequently reported presentations. The mortality rate in our cohort was 37%. CONCLUSION: This study is a territory-wide overview of the clinical and genetic characteristics of MD patients in a Chinese population, providing the first available prevalence rate of MD in Hong Kong. The findings of this study aim to facilitate future in-depth evaluation of MD and lay the foundation to establish a local MD registry.