Malignant Hyperthermia and Idiopathic HyperCKemia

Abstract

Malignant hyperthermia (MH) is a rare but life-threatening condition that is more frequently encountered and discussed within the anesthesia literature. Here we through a case specifically discuss the susceptibility of individuals and/or families with asymptomatic unexplained elevations of creatine kinase (CK), also frequently referred to as hyperCKemia or idiopathic hyperCKemia (IHCK) in recent reports. The clinical implications would be to underscore the importance of this as a susceptibility to developing MH and highlight the importance of genetic susceptibility testing in such cases. Anesthesiologists and critical care intensivists as well as primary care physicians should keep this in mind when seeing patients with asymptomatic hyperCKemia and potentially inform them about the possibility of developing MH if exposed to triggering agents. Genetic susceptibility testing should be considered if available and family members should also receive nontriggering agents when undergoing anesthesia and wear Medic Alert tags.

Idiopathic hyperCKemia and malignant hyperthermia susceptibility

“…This suggests that patients with idiopathic hyperCKemia may have an RYR1-associated myopathy, and it emphasizes the need for extensive investigation before establishing the diagnosis of idiopathic hyperCKemia. 32 The presence of dysmorphisms detected during a physical examination in most of the MHS patients in this study could be another factor raising the possibility of MH in the investigation of idiopathic hyperCKemia. This is further supported by the presence of dysmorphisms in some diseases associated with MH, such as the King-Denborough syndrome and Native American myopathy.…”

“…14,19,30 In our study, the death of relatives during surgery or physical activity was an indicator of subsequent MH susceptibility, and it is clinical information that could guide research early on towards MH. In this regard, Sunohara et al 31 reported a patient with idiopathic hyperCKemia whose sister presented with MH, and Kasi 32 emphasizes that families with idiopathic hyperCKemia should receive guidance and be investigated for MH, even if family members were asymptomatic. Kasi reported a family with idiopathic hyperCKemia where a member developed anesthetic-induced MH and was found to have a causative RYR1 mutation.…”

Muscular body build and male sex are independently associated with malignant hyperthermia susceptibility

“…13 Twenty-five percent of severe MH episodes have occurred in elite athletes. 12 There have also been other reports of athletes suffering MH episodes both with 14,15 and without exposure to anesthesia. [16][17][18] It was previously noted that three of 25 Danish individuals who experienced MH episodes were elite athletes competing at the international and Olympic levels.…”

The Changing Face of Malignant Hyperthermia: Less Fulminant, More Insidious

“…Although asymptomatic increased CK levels have, for years, been considered not to be a reliable predictor of MH susceptibility, leading to the abandonment of the serum CK level as a screening test for MH 29 , in our opinion a watchful eye is still advised. Indeed, RYR1 mutations such as c.1021G>C (Gly341Arg) and c.487C>T (Arg163Cys) can be a specific cause of chronically elevated CK activity in patients with strictly normal histological findings 30,31 . Postoperative rhabdomyolysis, certainly if CK is more than 10,000 U/l without, and more than 20,000 U/l with, the use of succinylcholine, is very suspect and either points at an underlying myopathy or MH susceptibility.…”