Aortic Root Surgery with Hypothermic Circulatory Arrest in a Patient with Malignant Hyperthermia and Osteogenesis Imperfecta: A Bridge Too Far

Malignant hyperthermia (MH) is a rare and life-threatening disorder of skeletal muscle most often triggered by volatile anaesthetic gases and succinylcholine that can lead to a dramatic increase in body temperature with possible fatal outcomes. It especially presents following succinylcholine administration but has also been reported in patients undergoing surgeries involving cardiopulmonary bypass (CPB) with only 30 cases described so far in the current literature. Osteogenesis imperfecta (OI), also known as “brittle bone disease” is a rare disorder of connective tissue characterized by fragile bones that can easily break, often from little or no apparent trauma. While musculoskeletal abnormalities are well described in osteogenesis imperfecta, cardiovascular involvement is rare. When the heart is involved, osteogenesis imperfecta (OI) preferentially affects the left-sided heart valves, for unclear reasons, leading to aortic and mitral regurgitation. However, aortic root dilation is the most common cardiovascular manifestation. Here we present a patient with confirmed malignant hyperthermia (MH), osteogenesis imperfecta (OI), a bicuspid aortic valve and associated aortic aneurysm, who underwent cardiac surgery with hypothermic circulatory arrest (HCA). Despite avoidance of known triggering agents, recommended peri-operative management and subsequently, active cooling, intravenous dantrolene administration and multiorgan support, the patient succumbed from complications most likely associated with the combination of malignant hyperthermia (MH) and osteogenesis imperfecta (OI).