Diaphragmatic paralysis: a clinical imitator of cardiorespiratory diseases.

Diaphragmatic paralysis has a predictable effect on lung function. However, the symptoms depend on the preexisting heart-lung diseases and may mimic various cardiorespiratory processes. We describe the presentation in six patients. In a fit man, unilateral diaphragmatic paralysis caused dyspnea only at strenuous exercise. In a patient with emphysema it caused dyspnea mainly when carrying light weights. In another patient with emphysema it caused life-threatening hypoxemia simulating parenchymal lung disease. A patient with mild chronic obstructive lung disease and nocturnal wheezing following the onset of ULDP was believed for 15 years to have asthma. A patient with bilateral diaphragmatic weakness had severe choking sensation only in the supine position, simulating upper airway obstruction or heart failure. Afemale patient suffered nocturnal sweating due to ULDP. The clinical manifestations of diaphragmatic paralysis vary and can mimic a wide range of cardiorespiratory diseases.