Malignant hyperthermia: reviewing important aspects

Abstract

A hipertermia maligna (HM) é uma doença farmacogenética rara, de caráter autossômico dominante, de baixa incidência, porém potencialmente fatal, desencadeada por exposição a agentes anestésicos inalatórios halogenados e/ou succinilcolina. Caracteriza-se por um quadro de hipermetabolismo do músculo estriado esquelético, por hipercalcemia intracelular, com destruição completa deste, associado ao aumento do consumo de oxigênio, hipertermia, alterações cardiovasculares, rigidez muscular, acidose metabólica, falência renal e morte, caso não seja realizado o tratamento específico com o dantrolene. O reconhecimento da crise é baseado nos sinais clínicos que autorizam o início do tratamento e o diagnóstico definitivo é realizado a partir do teste de contratura halotano/cafeína realizado no paciente e em seus familiares com o intuito de descobrir os suscetíveis e protegê-los de possíveis crises.

Malignant Hyperthermia in Bariatric Surgery: A Case Study With Clinical, Pathophysiological, Biochemical and Biophysical Correlations

“…Muscle relaxation occurs when stimulation of the motor nerve stops and the intracellular adenosine triphosphate (ATP)-dependent Ca 2+ pump transports intracytoplasmic Ca 2+ into the sarcoplasmic reticulum lumen [ 5 , 7 , 13 , 14 ]. MH is a calcium channelopathy of skeletal muscle [ 15 ] in which a constant increase of intracytoplasmic Ca 2+ concentration occurs causing a change in cellular metabolism [ 5 , 7 - 9 , 13 ]. A hypermetabolic state develops when susceptible patients are exposed to halogenated volatile inhalational anesthetic agents (halothane, isoflurane, enflurane, sevoflurane, desflurane and methoxyflurane), depolarizing muscle relaxants (e.g., succinylcholine), and/or extreme physical activity in hot environments [ 3 , 7 , 8 , 16 - 18 ].…”

“…A hypermetabolic state develops when susceptible patients are exposed to halogenated volatile inhalational anesthetic agents (halothane, isoflurane, enflurane, sevoflurane, desflurane and methoxyflurane), depolarizing muscle relaxants (e.g., succinylcholine), and/or extreme physical activity in hot environments [ 3 , 7 , 8 , 16 - 18 ]. The MH clinical incidence is estimated to be from 1 in 10,000 - 30,000 to 1 in 100,000 - 250,000 in patients undergoing anesthesia, depending on geographic localization and age [ 6 , 9 ]. Nevertheless, the prevalence of genetic variants or mutations of an individual susceptible to MH is estimated to be 1 in 2,000 - 3,000 [ 5 , 6 , 10 ].…”

“…In addition, protocols must be established to control or prevent complications associated with the clinical condition of the disease. These include external (if necessary, internal) cooling of the patient’s body, hyperventilation with 100% oxygen, correction of metabolic acidosis, adjustment of cardiac arrhythmias, dialysis to remove anesthetic residues and aid in blood filtration to revert metabolites to normal levels [ 3 , 6 , 8 , 9 ].…”