About Malignant Hyperthermia

Overview

Malignant hyperthermia (MH) is a severe reaction that can occur in certain individuals who have a genetic predisposition when exposed to certain anesthesia drugs used during surgery. It is characterized by a rapid increase in heart rate and body temperature, abnormally fast breathing, muscle rigidity, breakdown of muscle fibers, and increased acid levels in the blood. If not promptly treated, MH can lead to organ dysfunction, including cardiac arrest and renal failure, and can be life-threatening. MH is triggered by specific anesthetic gases and muscle relaxants used during surgical procedures. It is important to take this risk seriously and be aware of any personal or family history of MH when undergoing surgery. If you have concerns about MH, it is best to consult with your healthcare professional before any surgical procedure.

Causes and Risk Factors

Malignant hyperthermia is a severe reaction to certain anesthesia drugs. MH is often associated with genetic changes, particularly in the RYR1 gene. Other genes like CACNA1S and STAC3 can also be involved. Inheritance of the gene for MH susceptibility (MHS) plays a role, but it can also occur due to random genetic changes. If a person has a family member with MHS, they have a 50% chance of inheriting it.

Certain factors that may increase the risk of developing MH include:

• Environmental triggers: Exposure to specific anesthesia drugs or previous episodes of MH
• Age: Although not fully understood, some studies suggest that younger individuals may have a higher risk of developing MH.

It's important to note that these risk factors are not definitive and individual susceptibility to MH can vary. If you have concerns about your risk for MH, it's best to discuss them with your healthcare professional.

Symptoms

The most common early symptoms of malignant hyperthermia include:

• Increased heart rate
• Increased carbon dioxide production
• Muscle rigidity
• Rapid increase in body temperature

Other common symptoms that may occur with later stages, progression, or higher severity of malignant hyperthermia include:

• Rigid muscles or muscular spasms
• Bleeding
• Dark or brown urine
• Fast heart rate
• Cardiac arrest
• Difficulty breathing
• High body temperature
• Rapid breathing
• Unusual skin coloration
• High levels of potassium in the blood

The presence and severity of symptoms can vary depending on factors such as genetic predisposition, the dose of triggering agents, and the duration of exposure. If you experience any symptoms or suspect malignant hyperthermia, seek immediate medical attention.

Diagnosis

To diagnose MH, the following examinations, tests, and procedures are commonly performed:

• Physical exam: During this routine procedure, the healthcare provider looks for physical signs of a medical problem like pain, swelling, or masses in the body.
• Lab tests: These may include blood draws to check for specific markers associated with malignant hyperthermia, such as elevated creatine kinase levels after exercise or metabolic acidosis.
• Imaging studies: X-rays or MRI scans may be recommended to assess the condition further.

To determine the stage or severity of malignant hyperthermia, additional examinations, tests, and procedures may be performed include:

• Clinical procedures: These can vary depending on the body system being evaluated and may involve hearing tests or other specialized assessments.
• Referral for out-patient procedures: In some cases, more specialized clinical procedures may be required.
• Additional lab tests: These tests may include assessing certain enzyme levels and concentrations.

It's important to follow up with your healthcare provider if your symptoms worsen or change after any of these exams. They can provide further guidance based on your individual situation.

Treatment Options

The goals of treatment for MH are to provide immediate relief, prevent complications, and ensure patient safety. Here are the recommended treatment options and how they work to achieve these goals:

• Stopping Triggering Drugs: The first step is to discontinue the use of the medications to prevent further progression of symptoms.
• Medication: Dantrolene is a direct-acting skeletal muscle relaxant that is specifically used to treat MH. It prevents or reduces the excessive calcium release that occurs during an MH reaction.
• Addressing Complications and Symptoms: Medical staff will address any complications or symptoms that arise from MH, such as extremely high body temperatures, trouble breathing, or irregular heart rhythms. Treatment may include using cold intravenous fluids and ice packs to cool the body, providing additional oxygen through a tube or mask, and offering medications to treat an irregular heartbeat.
• Supportive Care: Patients with MH are typically taken to the intensive care unit (ICU) for monitoring after stabilization. Additional tests may be run in the ICU.

It's important to note that these treatment options should be administered by medical professionals in a controlled setting.

Medication dosing may be affected by many factors. Check with your health care professional about dosing for your individual situation. Other side effects can occur. Check with your health care professional or read the information provided with your medication for additional side effect information.