Understanding Anesthesia Allergies: Causes, Risk Detection, and Prevention Methods

Exploring the origins of "14 surnames linked to anesthesia allergies" and their risk for Malignant Hyperthermia (MH), a sudden high fever during surgery that can be life-threatening, along with preparation steps before anesthesia.

The topic of 14 surnames linked to anesthesia allergies stems from past medical research identifying certain Thai families with genetic defects. When exposed to inhaled anesthetics, these groups exhibit unusually severe reactions. These surnames have been compiled into a database for anesthesiologists to monitor patients with heightened caution.

What is anesthesia allergy and what causes it?

Generally, what people call "anesthesia allergy" includes two main categories: common side effects like nausea, vomiting, or dizziness after waking up, and true allergic reactions to anesthesia, which are further divided into:

• Anaphylaxis: A severe, acute allergy to anesthetics or muscle relaxants where the immune system overreacts, causing a drop in blood pressure and difficulty breathing.
• Malignant Hyperthermia (MH): A rare but extremely serious genetic complication where the body temperature rises rapidly and muscles stiffen upon exposure to certain inhaled anesthetics.

How can we know if we are "allergic to anesthesia"?

This presents a medical challenge because "there is no general skin allergy test for anesthetics" like there is for antibiotics—except if the patient has a suspected prior allergy. Doctors assess risk by:

• Family history: If a close relative died or experienced coma during anesthesia, notify the doctor immediately, as MH is genetically inherited.
• History of allergies to drugs or chemicals: For example, allergies to seafood, latex, or past skin rashes from certain medications.
• Specialized testing: If necessary, doctors may order blood tests or muscle biopsies when MH is strongly suspected.

What anesthesia allergy symptoms indicate a life-threatening condition?

Allergic reactions can occur from the start of anesthesia through surgery, with warning signs including:

• Skin system: Red rash, hives, or swelling of the face and eyes.
• Respiratory system: Bronchospasm causing wheezing and difficulty breathing.
• Cardiac system: Rapid blood pressure drop (shock), irregular heartbeat, or cardiac arrest.
• MH condition: Sudden high fever (sometimes over 40°C), dark-colored urine resembling soda due to muscle breakdown.

How to prevent and prepare safely against anesthesia allergy risks.

The best prevention is providing complete information to the anesthesiologist before surgery, including:

• Fasting as instructed: To prevent lung aspiration during anesthesia.
• Disclose all drug allergies: Including herbs and dietary supplements currently taken.
• Report past surgeries: Especially if abnormal reactions occurred after anesthesia, such as severe nausea.
• Consult about heredity: Check with relatives whether anyone has had problems with anesthesia.

Regarding genetic screening for Malignant Hyperthermia (MH), commonly referred to as "anesthesia allergy," medical technology has advanced enough to test before any surgical incident occurs.

Steps for genetic screening to assess anesthesia allergy risk.

This testing focuses on detecting abnormalities in the RYR1 and CACNA1S genes, which are primary causes of MH, following these steps:

1. Genetic Counseling and Evaluation.

Before testing, doctors take a detailed history, especially regarding:

• Any immediate family member who died or had a critical event during anesthesia.
• Family history involving the "14 high-risk surnames" or known drug allergy cases.
• Whether the patient has muscle weakness or other genetic disorders.

2. Sample Collection.

Currently preferred and least invasive methods include:

• Blood test: To extract DNA from white blood cells.
• Buccal swab: Using a cotton swab to gently collect cheek cells, often used for children or when blood draws are inconvenient.

3. Laboratory Analysis.

Labs use Next-Generation Sequencing (NGS) to detect gene mutations linked to MH. If abnormalities matching risk databases are found, doctors diagnose "MH Susceptible" (high-risk group).

In Thailand, facilities capable of MH risk testing via DNA and muscle biopsy are mainly centralized at university hospitals and large genetics centers, such as Siriraj Hospital, Chulalongkorn Hospital (Thai Red Cross), Ramathibodi Hospital, and leading private hospitals like Bumrungrad and Bangkok Hospital.

Those with government health insurance or social security can access testing if medically indicated, such as having a close relative who died from anesthesia allergy. The process begins at the designated hospital to obtain a referral to a university hospital. DNA testing costs typically range from 5,000 to 15,000 baht depending on gene number and hospital.

DNA testing is safe and about 60-80% accurate. A positive result grants the patient an "MH risk identification card" to present to anesthesiologists before surgery, ensuring 100% accurate life-saving precautions.

Sources:Mayo Clinic,MHAUS