Phrenic nerve involvement in Charcot-Marie-Tooth disease.

Diaphragmatic weakness in Charcot-Marie-Tooth (CMT) disease may be more common than generally acknowledged. Recognizing diaphragmatic weakness in a patient with CMT is important since recognition of this process may help explain the symptoms of breathlessness and orthopnea, as well as the development of hypercarbia. Although most patients with CMT have a normal lifespan, the subset of patients with diaphragmatic weakness may be at a higher risk of pulmonary morbidity and early mortality. Elevation of one or both hemidiaphragms on chest roentgenogram should raise the suspicion of diaphragmatic dysfunction and prompt further investigation.