Uncontrollable high-frequency tachypnea in a case of unilateral medial medullary infarct.

Background: Medullary infarcts can be associated with breathing disorders that usually consist in central hypoventilation.

Patient: We describe the case of a 54-year-old man, fully conscious, presenting with an uncontrollable high frequency and shallow tachypnea (95/min) at the onset of a unilateral medial medullary infarct. This disorder disappeared under inspiratory pressure support mechanical ventilation.

Measurements And Results: Respiratory drive (respiratory rate, occlusion pressure, and mean inspiratory flow), efferent pathway (transcranial and cervical magnetic stimulation), and afferent pathway (response to CO(2) and to lung inflation) were investigated. The respiratory drive was increased. The phrenic nerve conduction time was normal. The sensitivity of the central pattern generator to lung inflation and to CO(2) was preserved. The territory of the infarct was supplied by the spinal anterior artery.

Conclusions: An extremely rapid and shallow tachypnea due to the increase in respiratory drive can be associated with unilateral medullary infarction.