Malignant hyperthermia during a prolonged anesthetic for reattachment of a limb

Malignant hyperthermia in the early days of pediatric anesthesia: an interview with anesthesiology pioneer, Dr. John F. Ryan

Dr. John F. Ryan (1935 - ), Associate Professor of Anaesthesia at the Harvard Medical School, influenced the careers of hundreds of residents and fellows-in-training while instilling in them his core values of resilience, hard work, and integrity. His authoritative textbook, A Practice of Anesthesia for Infants and Children, remains as influential today as it did when first published decades ago. Although he had had many accomplishments, he identified his experiences caring for patients with malignant hyperthermia and characterizing the early discovery of this condition as his defining contribution to medicine. Based on a series of interviews with Dr. Ryan, this article reviews a remarkable career that coincides with the dawn of modern pediatric anesthetic practice.

Orthotopic liver transplantation in a malignant hyperthermia susceptible patient

We present a patient with hepatitis C and D and hepatocellular carcinoma who underwent preoperative evaluation for orthotopic liver transplantation. In his past medical history, he reported a life-threatening event during tonsillectomy in 1975. Intubation was impossible due to extreme jaw muscle tension, followed by excessive elevation in body temperature, tachycardia, and coma for a few days. We evaluated him for malignant hyperthermia, according to the European Malignant Hyperthermia Group Protocol, and found him highly positive in both the halothane and caffeine test, respectively. Three months later, we performed an orthotopic liver transplantation. During retransplantation 4 years later, due to ischemic-type biliary lesions, he suffered massive intraoperative bleeding. Blood products, as well as coagulation factors and aprotinin, were well tolerated. Anesthesia was performed in a trigger-free total intravenous technique without dantrolene prophylaxis, but dantrolene was readily available in sufficient quantities in the operating room. The patient did not encounter a malignant hyperthermia crisis in either perioperative period.

Delayed onset of malignant hyperthermia in desflurane anesthesia

IMPLICATIONS

Animal-experimental studies demonstrate desflurane's trigger effect for malignant hyperthermia (MH). In contrast to other anesthetics, the time interval from exposure to the occurrence of symptoms is much longer with desflurane. This case report focuses on MH induced by desflurane alone.

Malignant hyperthermia and neuromuscular disease

Malignant hyperthermia (MH) is a rare clinical syndrome characterized by hypermetabolism and triggered by specific anesthetic agents. The mechanism of this abnormal reaction is due to uncontrolled calcium flux in the skeletal muscles resulting in a variable clinical syndrome of muscle rigidity, respiratory and metabolic acidosis, and elevation of temperature. The specific genetic defect underlying this condition has not been identified in humans, though in susceptible swine a mutation of the gene for the ryanodine receptor, a large protein which comprises the calcium channel in the sarcoplasmic reticulum, has been identified recently. Inheritance in humans appears to be autosomal dominant with variable penetrance. Patients with MH rarely have physical or laboratory signs of muscle disease. However, scattered case reports and investigations of individuals with known myopathies and other muscle related problems, such as acute rhabdomyolysis or idiopathic persistently elevated creatine kinase, suggest a possible association of MH with a variety of neuromuscular diseases and stress syndromes. This association is very strong in the case of central core disease (CCD) where it is supported by clinical and laboratory evidence, including the proximity of the CCD gene to the ryanodine receptor gene on chromosome 19. A variety of other diseases have been implicated and can be classified as possibly associated (King-Denborough syndrome, Duchenne muscular dystrophy) or unlikely to be associated (myotonia congenita, sudden infant death syndrome, limb girdle dystrophy, neuroleptic malignant syndrome, etc.).(ABSTRACT TRUNCATED AT 250 WORDS)

Dantrolene. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic use in malignant hyperthermia, the neuroleptic malignant syndrome and an update of its use in muscle spasticity

Dantrolene sodium acts primarily by affecting calcium flux across the sarcoplasmic reticulum of skeletal muscle. Recently, dantrolene has been used very successfully in the treatment of several rare hypercatabolic syndromes which have previously been associated with high mortality rates. In malignant hyperthermia, where early diagnosis and treatment usually with intravenous dantrolene in association with other supportive measures (and often subsequent dantrolene therapy) is performed, recovery is seen in virtually 100% of patients. There is a rapid resolution of hyperthermia, dysrhythmias, muscle rigidity, tachycardia, hypercapnia, mottled or cyanotic skin, and metabolic acidosis, and a slower normalisation of myoglobinuria and elevated serum creatine phosphokinase levels. In patients with family history or previous episodes of malignant hyperthermia, prophylactic treatment with dantrolene prior to anaesthesia prevents the syndrome occurring in most cases. Where malignant hyperthermia has developed patients have been successfully treated with further dantrolene therapy. Dantrolene has also been used successfully in the treatment of a few cases of heat stroke and the neuroleptic malignant syndrome--both of which have many similarities to malignant hyperthermia. Dantrolene is well established in the treatment of patients with muscle spasticity where it generally improves at least some of the components of spasticity (i.e. hyper/hypotonia, clonus, muscle cramps and spasms, resistance to stretch and flexor reflexes, articular movement, neurological and motor functions and urinary control). However, in some patients, particularly those with multiple sclerosis, dantrolene may not be effective, and in many cases muscular strength may diminish. Long term dantrolene therapy has been associated with hepatic toxicity and may cause problems in patients treated for disorders of muscle spasticity. Thus, dantrolene offers a unique advance in the therapy available for the treatment of hypercatabolic disorders and is also useful in the treatment of muscle spasticity of various aetiology.