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Severe Masseter Muscle Rigidity Following Succinylcholine Administration in a Patient with Inconclusive Pharmacogenetic Results for Susceptibility to Malignant Hyperthermia: A Case Report |
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| รหัสดีโอไอ | |
| Creator | Chanapat Charoensuk |
| Title | Severe Masseter Muscle Rigidity Following Succinylcholine Administration in a Patient with Inconclusive Pharmacogenetic Results for Susceptibility to Malignant Hyperthermia: A Case Report |
| Contributor | Jedniphat Intrapongpan, Naruemon Vattanasiriporn, Thitinuch Ruenhunsa, Saranyoo Nonphiaraj, Sarinya Chanthawong |
| Publisher | Faculty of Medicine, Srinakharinwirot University |
| Publication Year | 2569 |
| Journal Title | Journal of Medicine and Health Sciences |
| Journal Vol. | 33 |
| Journal No. | 1 |
| Page no. | 74-78 |
| Keyword | masseter muscle rigidity, succinylcholine, malignant hyperthermia, RYR1 protein, CACNA1S protein, anesthesia |
| URL Website | https://he01.tci-thaijo.org/index.php/jmhs |
| Website title | TCI ThaiJO |
| ISSN | 2651-2084 |
| Abstract | Masseter muscle rigidity following succinylcholine is traditionally viewed as a potential early indicator of malignant hyperthermia (MH), although most adult cases remain isolated without systemic progression. We report a 50-year-old woman who developed immediate, severe bilateral masseter rigidity after succinylcholine during induction of general anesthesia. Despite profound limitation in mouth opening of approximately 1.5 cm, videolaryngoscopic intubation was achieved on the first attempt, and mask ventilation remained uncomplicated. The rigidity persisted even after administration of cisatracurium, yet the patient demonstrated no systemic signs of MH, with normal hemodynamics, end-tidal CO2, temperature, and laboratory values. Surgery was cancelled, and the rigidity gradually resolved during recovery in the intensive care unit. Targeted genetic testing for RYR1 and CACNA1S variants did not identify pathogenic mutations. However, given the limited scope of the tested variants, the result was considered inconclusive for determining MH susceptibility. This case illustrates that marked succinylcholine-induced masseter rigidity can occur without progression to systemic MH. It also highlights that nondiagnostic targeted genetic testing reflects current limitations in variant detection and should not be interpreted as definitively excluding susceptibility. In patients presenting with significant isolated masseter rigidity, continued MH preparedness remains warranted despite the absence of systemic manifestations during the initial event. |
