SEARCH RESULTS FOR: Malignant-Hyperthermia

Malignant Hyperthermia

Malignant Hyperthermia: Pathogenesis & clinical findings Authors: Haotian Wang, Jen Guo Reviewers: Julena Foglia, Priyanka Grewal, Luiza Radu Kevin Gregg* * MD at time of publication Depolarizing muscle relaxant (e.g., succinylcholine) & volatile anesthetic (e.g., sevoflurane, desflurane, isoflurane, halothane, NOT nitrous oxide) Autosomal dominant mutation in ryanodine receptor (RyR1; RyR1 transports calcium out of the sarcoplasmic reticulum during muscle depolarization) LowerthresholdforactivationofRyR1 state Prolonged opening of RyR1 ↑ Ca2+ in myocyte cytoplasm Capacity of the reuptake protein to carry Ca2+ is overwhelmed Sustained muscle contraction à hypermetabolic state Malignant Hyperthermia Vigorous exercise & heat (rare) Rare life-threatening clinical syndrome that occurs in genetically susceptible patients upon exposure to a triggering agent Skeletal muscle rigidity (i.e., masseter muscle spasm) Sustained muscle contraction Myocytes (muscle cells) deplete available ATP Hypermetabolic state ↑ O2 consumption ↑ Heart rate to meet O2 demand ↑ CO2 production Unexplained ↑ end tidal CO2 (early sign) ↑ Temperature Hyperthermia (late sign) ↓ O2 supply ↑ Anaerobic metabolism ↑ Lactic acid production Metabolic acidosis Cell death Leakage of muscle contents into circulation ↑ Serum creatinine kinase Development of rhabdomyolysis (rapid breakdown of muscle tissue) Myoglobinuria (presence of excess myoglobin in urine) Acute kidney injury** Hyperkalemia Electrolyte imbalances (i.e., hyperkalemia) Abnormal myocyte contraction Cardiac dysfunction Dysrhythmias Cardiovascular collapse Release of thromboplastin (converts prothrombinàthrombin) & other prothrombotic substances (promotes clot formation) Imbalance between thrombotic & antithrombotic pathway ↑ Clot formation from activation of the extrinsic & common pathways Disseminated intravascular coagulation** Tachypnea (in absence of prominent mechanical ventilation) Tachycardia (early sign) Cardiovascular collapse Vital organ failure Coma **See corresponding Calgary Guide slide(s) Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published Oct 25, 2015; updated Oct 2, 2024 on www.thecalgaryguide.com

Hyperthermie maligne

Hyperthermie maligne: pathogenèse et résultats cliniques