Myotonic dystrophy type 1 presenting with ventilatory failure

A case report of malignant hyperthermia in a patient with myotonic dystrophy type I: A CARE-compliant article

RATIONALE

Several hereditary myopathies that can predispose to malignant hyperthermia (MH) are reported. However, the risk of MH in myotonic dystrophy type I (DM1) has been suggested equal to general population, although the evidence is limited to only a few case reports.

PATIENT CONCERNS

We encountered a rare case of MH during anesthesia induction with sevoflurane in a male adolescent with previously undiagnosed DM1.

DIAGNOSES

After the event, genetic testing revealed the presence of a previously unknown heterozygous missense mutation in ryanodine receptor 1 (RYR1) associated with MH (c.6898T > C; p.ser2300Pro). Concomitantly, the patient was diagnosed with DM1 with abnormal cytosine-thymine-guanine triplet expansion in the DMPK gene.

INTERVENTIONS

Dantrolene was administered to treat the hypermetabolic manifestations in 20 minutes after the identification of MH.

OUTCOMES

The patient was successfully treated and discharged without any complications. Laboratory abnormalities were recovered to baseline at postoperative 4 days.

LESSONS

The authors suggest that possible MH susceptibility in DM1 patients may be refocused. Genetic testing can be a screening tool for MH susceptibility in these population, prior to receiving general anesthesia.

Bilevel positive airway pressure therapy in a patient with myotonic dystrophy and postoperative respiratory failure: A case report

Respiratory failure is a common complication in patients with myotonic dystrophy (MD) and might be a presenting symptom in the perioperative setting. We report the case of a 59-year-old woman with MD who underwent open cholecystectomy and developed postoperative respiratory failure. Without reintubation, the patient was successfully managed with bilevel positive airway pressure (BiPAP) and was discharged uneventfully. BiPAP may be considered as an alternative for postoperative respiratory failure in patients with MD. Careful observation of patients' postoperative condition and an earlier application of BiPAP are instrumental in avoiding retracheal intubation, which may cause further serious problems in patients with MD.

Pulmonary thromboembolism in a patient with myotonic dystrophy type 1

Thromboembolism is a rare complication in patients with myotonic dystrophy. While immobilization of patients with advanced disease predisposes to high risk for venous thromboembolism, hypercoagulability could account for venous thromboembolism in patients without impaired mobilization. We report a patient with myotonic dystrophy type 1 who developed pulmonary thromboembolism unrelated to immobilization.

Lesson of the month (1). Myotonic dystrophy and out-of-hospital arrest

Myotonic dystrophy (MD) is an autosomal dominant disorder which affects both smooth and skeletal muscles. The incidence is approximately 1 in 8,000 births. It is the most common muscular dystrophy to manifest in adulthood, and the second most common skeletal muscle disorder after Duchenne MD. Cardiac rhythm disturbances are a common cause of death in these patients. This lesson describes a case in which a previously undiagnosed case of MD presented with an episode of ventricular fibrillation.