Between Strength and Stillness: The Tale of Myotonia in an Adult Warrior: A Case Report

Myotonic Dystrophy type 1 (DM1) is an autosomal dominant multisystem disorder characterized by progressive muscle weakness, myotonia, and involvement of multiple organ systems, with variable clinical presentations. We present the case of a 39-year-old male soldier who initially sought evaluation for non-anginal chest pain and was subsequently found to have distal upper limb weakness and difficulty making a fist over a two-year period. Neurological examination revealed subtle bilateral lower motor neuron facial palsy, neck flexor weakness, muscle wasting in the left deltoid and supraspinatus, along with percussion and hand grip myotonia. Electromyography showed typical myotonic discharges, and genetic testing confirmed an expanded CTG trinucleotide repeat in the DMPK gene, establishing the diagnosis of DM1. Comprehensive systemic and cardiac evaluation showed no abnormalities. This case highlights the diagnostic challenges posed by the heterogenous manifestations of DM1 and underscores the need for heightened clinical suspicion when encountering patients with subtle neuromuscular symptoms and myotonia. Early identification is essential for appropriate multidisciplinary management that addresses potential complications such as cardiac conduction defects and ultimately improves patient outcomes. Additionally, this report adds valuable insight into the phenotypic spectrum of DM1 in adult patients, emphasizing the importance of detailed clinical and electrophysiological assessment supported by genetic confirmation. Raising awareness about this rare but impactful condition can facilitate timely diagnosis and personalized care.