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Malignant hyperthermia susceptibility in adult patients with masseter muscle rigidity
1Department of Anesthesiology, Hahnemann University, Philadelphia, Pennsylvania 19102-1192.
Abstract:
We sought to determine the incidence of malignant hyperthermia (MH) susceptibility in adult patients with a previous episode of masseter muscle rigidity (MMR). The medical records and in vitro contracture test results of all patients over 15 years of age tested for MH because of previous MMR from 1985 to 1988 were reviewed. The number of children (age less than 16 yr) tested for MH because of previous MMR was also determined for the same four-year period, for comparison of coincidence rates. Six of 24 adult patients (25 per cent) were proved MH-susceptible by in vitro contracture testing. No clinical sign associated with the episode of MMR was predictive of MH-susceptibility. Two of six MH-susceptible patients developed acute MH following MMR. In the same four-year period, 75 children were tested for MH-susceptibility because of previous MMR; 44 (59 per cent) had a positive in vitro contracture test. We conclude that the coincidence of MMR and MH-susceptibility is lower in adults than children. Episodes of acute MH do occur after MMR, but the onset of MH may be delayed. Conservative management of MMR in adult patients is recommended.
Insights
Malignant hyperthermia (MH) susceptibility is less common in adults with masseter muscle rigidity (MMR) than in children. While acute MH can occur after MMR, its onset may be delayed, warranting conservative management in adults.
Area of Science:
- Anesthesiology
- Medical Genetics
- Pharmacology
Background:
- Masseter muscle rigidity (MMR) is a potential indicator of malignant hyperthermia (MH) susceptibility.
- Previous studies have indicated a higher incidence of MH susceptibility in pediatric patients experiencing MMR.
Purpose of the Study:
- To determine the incidence of MH susceptibility in adult patients with a history of MMR.
- To compare the coincidence rates of MMR and MH susceptibility between adult and pediatric populations.
- To identify predictive clinical signs of MH susceptibility associated with MMR episodes.
Main Methods:
- Retrospective review of medical records and in vitro contracture test results for adult patients (≥16 years) tested for MH due to prior MMR (1985-1988).
- Determination of the number of pediatric patients (<16 years) tested for MH due to prior MMR during the same period.
- Analysis of in vitro contracture test outcomes to confirm MH susceptibility.
Main Results:
- Six out of 24 adult patients (25%) with a history of MMR were confirmed to be MH susceptible.
- No clinical signs during the MMR episode predicted MH susceptibility in adults.
- Two MH-susceptible adults developed acute MH following MMR, with potentially delayed onset.
- In contrast, 44 out of 75 pediatric patients (59%) tested for MMR were found to be MH susceptible.
Conclusions:
- The coincidence of MMR and MH susceptibility is significantly lower in adults compared to children.
- Adult patients with MMR have a lower risk of MH susceptibility, but the risk is not negligible.
- Conservative management of MMR in adult patients is recommended due to the potential for delayed MH onset.