Abdominal Muscle Fasciculations and Amyotrophic Lateral Sclerosis Diagnosis in a Patient Unable to Perform Sit-Ups.

While performing sit-ups, a 70-year-old man was unable to lift his upper body. The abdominal skin reflex was absent, and abdominal ultrasonography showed intermittent, irregular, and localized muscle twitches of the abdominal muscles. Further, electromyography (EMG) detected widespread fasciculations. Amyotrophic lateral sclerosis (ALS) was diagnosed. Muscle ultrasonography (MU) is useful in detecting fasciculations. This technique allows for repeated non-invasive imaging and the assessment of an expansive range of muscles in real-time. It also detects deep abdominal muscles, which are difficult to assess using EMG. MU is particularly beneficial to patients with atypical ALS who experience truncal muscle weakness.