A Relative Had a Bad Reaction to Anesthesia

It depends what kind of reaction. Feeling sick, groggy, or having a sore throat afterward is very common and not inherited. But a severe, life-threatening reaction — a dangerously high temperature, rigid muscles, or an unexplained death during or soon after a general anesthetic — can be a sign of malignant hyperthermia (MH), which runs in families. If that describes a blood relative, tell your anesthetist; they can take simple precautions.

Malignant hyperthermia is a rare inherited reaction to certain anesthetic drugs (specific gases and one muscle relaxant). In susceptible people these drugs trigger a dangerous rise in body temperature, muscle rigidity and a racing heart. It's serious, but it's well understood and entirely avoidable: if you're known or suspected to be at risk, the anesthetist simply uses different, non-triggering drugs.

Yes. People with known or suspected MH have surgery safely all the time. The anesthetist uses a 'trigger-free' anesthetic — avoiding the gases and the muscle relaxant that cause it, and using a specially prepared machine. The key is that they know in advance, which is why telling them matters so much.

Tell them if any blood relative had a severe reaction, very high fever, or unexpected death under general anesthesia; if anyone has been diagnosed with malignant hyperthermia; if you had an unexplained high fever or muscle stiffness during a past anesthetic; or if a muscle disease runs in the family. Bring any details or records you can find — even rough information helps them plan.

No — they're completely different. Nausea, drowsiness, shivering and a sore throat after anesthesia are common, harmless and not inherited. Malignant hyperthermia is a rare, specific, life-threatening reaction during anesthesia. A relative simply feeling unwell afterward is not a sign of it.