Die Deutsche Maligne Hyperthermie Hotline – Retrospektive Analyse der Anfragen im Zeitraum 2011–2020

Background: Malignant hyperthermia (MH) is a rare pharmacogenetic muscular disorder. Exposure to triggering agents may result in life-threatening metabolic crises in affected individuals. Due to varying and unspecific clinical symptoms, diagnosis of an acute MH crisis is challenging, particularly because abortive or mild courses are more frequently observed. Due to the rarity of an acute MH crisis, the MH Hotline was established in Germany in 1985. It ensures continuous availability of an MH expert for consultation in case of an acute crisis, but also regarding strategic planning of necessary anaesthesiological procedures or diagnostics. Objectives: From 2011 to 2020, all incoming enquiries to the German MH-Hotline were evaluated. Particularly the frequency of consultation as well as the topics of the addressed questions were analysed. The potential patient benefit was assessed based on the urgency of the inquiry,. Materials and methods: All telephone enquiries to the German MH Hotline since 2011 were anonymously recorded using a standardised questionnaire. The questions raised during the consultation were categorised in single questions and subsequently reassigned to thematic complexes for further analysis. On suspicion of an acute MH crisis, the clinical grading scale (CGS) was calculated to predict MH susceptibility. The acute cases were compared to the prevalence of the ICD-10 code T88.3 in the German hospital diagnosis statistics in order to evaluate the relevance of the MH Hotline during treatment of these patients. Results: In total, 683 calls and 1,211 single questions to the hotline were recorded. During the observation period, the hotline received 62.5 (interquartile range 59 – 78.5) enquiries per year. Of these, 20 calls per year were related to acute cases of suspected MH (interquartile range 16 – 24,25). Median CGS was at 18 points (interquartile range 15 – 30) pursuant to an MH-rank of 3 (“somewhat less than likely“), while 47 cases corresponded to the MH-Rank 4 (“somewhat greater than likely”), 18 cases to MH-rank 5 (“very likely”) and 8 cases to MH-Rank 6 (“almost certain”). Prevalence of ICD-10 code T88.3 was recorded 4.7 times in the same period (interquartile range 3.5 – 5). Conclusions: An acute MH crisis is a potentially lethal complication of general anaesthesia. Early therapy is essential for the patient’s prognosis. In particular, the substantial variance of clinical symptoms challenges diagnosis and frequently requires professional expertise. For analysing trends relating to the variance of clinical symptoms, the site of occurrence and the incidence, we recommend submitting suspected cases to the European MH register and using ICD-10 code T88.3 in medical records. This enables the identification of possible targets to further optimise patient safety.