What is MH?13

Malignant hyperthermia (MH) is a pharmacogenetic disease that causes hypermetabolism, a fast rise in body temperature and severe muscle contractions when an affected person receives general anesthesia using volatile anesthetics or the paralytic succinylcholine.13

The disorder is due to an acceleration of the metabolism in skeletal muscle. The signs and symptoms of MH include hypercarbia, muscle rigidity, fast-rising body temperature, tachycardia, myolysis, increased ETCO2, hyperkalemia, and acidosis. Immediate treatment with the drug dantrolene sodium usually reverses the signs of MH. The underlying defect is abnormally increased levels of cellular calcium in the skeletal muscle.10

Time to treatment is critical2,3

An initial 20-minute delay in administration of dantrolene sodium raises the risk of complications to 30%2

Watch as Henry Rosenberg, MD, President of the Malignant Hyperthermia Association of the United States (MHAUS), provides insight into the importance of timely treatment during an MH crisis.

How prevalent is MH?

Incidences of MH during anesthesia procedures are estimated at 1 in 10,000 children compared with 1 in 50,000 for adults.10

Early signs of MH

There are multiple signs that may prompt a diagnosis of MH by anesthesia practitioners.

  • Hypercarbia is often the first clinical sign of MH. Other early signs include sinus tachycardia and masseter spasm14

How response time may affect MH treatment outcomes

Stopping the triggering agents and administering dantrolene sodium to the patient as quickly as possible are the greatest priorities in an MH crisis. The time and human resources needed to prepare and administer low-concentration formulations of dantrolene sodium may cause treatment delays.2,14

  • Every delay in treatment increases the risk of further complication during an MH crisis2
  • The risk of complications may increase to 30% with a 20-minute delay in treating MH from its first symptom2

High fluid volumes

With low-concentration, high-volume MH treatment, the MHAUS recommendation of 2.5 mg/kg loading dose of dantrolene sodium requires considerable volumes of sterile water for injection for the majority of patients (eg, 750 mL for a 100 kg patient).1,5-7

There are several potential complications which may arise from administering high fluid volumes. These complications may include pulmonary edema, acute respiratory distress syndrome (ARDS), increased alveolar to arterial oxygen gradient, hyponatremia, phlebitis, and cellulitis.15

Know more about MH

The Malignant Hyperthermia Association of the United States (MHAUS) is a nonprofit organization dedicated to promoting optimum care and scientific understanding of MH and related disorders. MHAUS provides guidelines for the treatment of MH.

View the MHAUS treatment guidelines.

For more MH information and education for healthcare professionals and patients, visit www.MHAUS.org.

Call the MHAUS hotline

If you are experiencing an MH emergency, please contact the toll-free hotline at 800.MH.HYPER (800.644.9737).

Indication and Important Safety Information