Contralateral diaphragmatic palsy after subcortical middle cerebral artery infarction without capsular involvement

Diaphragmatic palsy after acute stroke is a novel clinical entity and may result in a high incidence of respiratory dysfunction and pneumonia, which especially cause greater morbidity and mortality. Generally, internal capsule and complete middle cerebral artery (MCA) infarctions are major risk-factors for developing diaphragmatic palsy. Herein, we present a case with contralateral diaphragmatic palsy after a subcortical MCA infarction without capsular involvement. Dyspnea occurred after stroke, while a chest X-ray and CT study disclosed an elevated right hemidiaphragm without significant infiltration or patch of pneumonia. A phrenic nerve conduction study showed bilateral mild prolonged onset-latency without any significant right-left difference. This suggested a lesion causing diaphragmatic palsy was not in the phrenic nerve itself, but could possibly originate from an above central location (subcortical MCA infarction). We also discussed the role of transcranial magnetic stimulation study in the survey of central pathway and demonstrated diaphragmatic palsy-related orthopnea.