Myotonic Dystrophy Type 1 Presenting With Ventilatory Failure

Abstract

To report a series of patients with adult onset myotonic dystrophy type 1 (DM1) in whom the presenting symptom was ventilatory failure. Ventilatory failure is a common complication of DM1 and may be a presenting symptom in the setting of anesthesia or surgery, but it is not known to be a heralding manifestation. Case series. Three adults developed dyspnea leading to ventilatory failure, with no cardiac or pulmonary causes identified. Case 1 required intubation for ventilator support and was sedated with propofol. There was no clinical myotonia, and electromyography (EMG) demonstrated brief runs of myotonic discharges. Examination 3 weeks later off propofol revealed percussion myotonia, and EMG evidence of long runs of myotonic discharges. Genetic testing confirmed the diagnosis of DM1. Case 2 had cataracts and ptosis but no known diagnosis of DM and no previous neurological impairments. Case 3 was previously neurologically asymptomatic but her son had congenital DM1. The diagnosis was confirmed by EMG in cases 2 and 3, and both patients were managed with bilevel ventilation (BIPAP). Myotonic dystrophy type 1 should be considered in the differential diagnosis of acute ventilatory failure in adults.