Malignant Hyperthermia

By, Prof. Pirro Prifti

Abstract
Malignant Hyperthermia (MH), is a rare emergency that happened during General Anesthesia. In Albania, during five last years have three cases diagnosed with Malignant Hyperthermia (MH), and two of them have been fatal finishing with death of two patients. Only one is saved. Malignant hyperthermia (MH), is disease passed down through families that causes a fast rise in body temperature (fever) and severe muscle contractions when the affected person gets general Anesthesia. Malignant hyperthermia’s inheritance is Autosomal dominant. The defect is typically located on the long arm of chromosome 19 (19q13.1) involving the ryanodine receptor. More than 25 different mutations in this gene are linked with malignant hyperthermia. In this article I shall represents problems happened when during General Anesthesia, unexpected has e Malignant Hyperthermia. Malignant hyperthermia (MH), occurs in 1 in 5,000 to 50,000 instances (mainly in young people), in which people are given anesthetic gases. The most common triggering agents are volatile anesthetic gases, such as: Halothane, Sevoflurane, Desflurane, Isoflurane, Enflurane, Cyclopropane, Methoxyflurane; The depolarizing muscle relaxants suxamethonium and decamethonium, used primarily in general anesthesia. Other drugs that have been suspected of causing MH include catecholamines, phenothiazines, and monoamine oxidase inhibitors, caffeine. More frequent after ENT (ORL), squint or dental operation due to related with short anaesthetic procedures. Researchers have described at least six forms of malignant hyperthermia susceptibility, which are caused by mutations in different genes. Variations of the CACNA1S and RYR1 genes increase the risk of developing malignant hyperthermia. Tests about discovering of MH are North American Protocol: Suspicous clinical history for MH, or The standard procedure is the “caffeine-halothane contracture test”, CHCT. Is an invasive test. The fresh biopsy (under local anesthesia), is bathed in solutions containing caffeine or halothane and observed for contraction; under good conditions, the sensitivity is 97%, and the specificity 78%; the use of the “calcium-induced calcium release” test -in addition to the CHCT to make the test more specific. Genetic testing is being performed in a limited fashion to determine susceptibility to MH. In people with a family history of MH, analysis for RYR1 mutations may be useful. Signs and symptoms are:Tachycardia : one of the earliest but a non specific sign,Tachypnea : in spontaneously ventilating patients. Increased sweating, During fulminant acute MH, body temperature may increase at a rate of 1.8–3.6°F (1–2°C) every 5 minutes, Cyanosis, flushing or blanching of skin, Cola coloured urine• masseter spasm or generalised muscle rigidity or both, Capnogram – Gradually increasing EtCO2 not related to other possible causes.. Biochemical parameters: Respiratory with or without metabolic acidosis, Hypercarbia, Hyperkalemia, Hyper calcemia, Hyper phosphatemia, Lacticacidemia, Myoglobinuria, Increase in creatinine kinase: neither a constant feature nor signifies increase muscle metabolism in intra operative period, Abnormal coagulation tests. Diagnostic Criteria are: Muscle rigidity (generalized rigidity including severe masseter muscle rigidity); Muscle breakdown (CK >20,000/L units, cola colored urine or excess myoglobin in urine or serum, potassium above 6 mmol/l); Temperature increase (rapidly increasing temperature, T >38.8°C); Other (rapid reversal of MH signs with dantrolene, elevated resting serum CK levels); Family history (autosomal dominant pattern). Differential Diagnosis ccan be made with: Pheochromocytoma,, Thyrotoxicosis (thyroid storm), Sepsis, Transfusion reactions (acute haemolytic and non haemolytic), Allergic reactions, Central nervous system dysfunction (pontine hge, hypoxic ischemic encephalopathy etc.), Neuroleptic malignant syndrome, Alcohol withdrawal,Drug interactions (MAOI and meperidine), some sort of cronic myopathy. For susceptible patients to MH, must be an special anesthetic procedures and must be ready with use of Dandrolene. Some anesthetic drugs are considered safe.These include local anesthetics (lidocaine, bupivacaine, mepivacaine), opiates (morphine, fentanyl), ketamine, barbiturates, propofol , etomidate, benzodiazepines. The nondepolarizing muscle relaxants pancuronium, cisatracurium, atracurium, mivacurium, vecuronium and rocuronium also do not cause MH. There is mounting evidence that some individuals with malignant hyperthermia susceptibility may develop MH with exercise and/or on exposure to hot environments, Local anaesthetics, Droperidol . Acute Management of MH crisis include:Stop exposure of triggering agents and give 100% O2, notify surgical team to abort intervention, administer 2.5mg/kg Dandrolene ( or Azumolene) in repeated doses and 3 gr Mannitol, place the catheter Foley, monitor core temperatre, O2, CO2, urine output, Astrupograme, correct HperKalemi or other biochimic abnormality, correct cardiac problems. Conplications are plenty after Therapy as: Kidney failure rhabdomyolisis, KID, Respiratory failure, muscular dystrophy. Mortality was greater than 80% when do not put the right diagnosis, but with correct and fast diagnosis and the current management, however, mortality is now less than 5%.

https://doi.org/10.58944/nojq6188