Dyspnoea exaggerated in the supine position and during exertion--diagnostic challenge.

The case of dyspnoea, exaggerated when in the supine position and during exertion, as a result of severe weakness of the diaphragm is reported. The aim of the study was to present a rare case of idiopathic bilateral diaphragmatic paresis (BDP) and to describe all the diagnostic procedures necessary to perform differential diagnostics. In order to establish the final diagnosis, chest radiography, haemodynamic evaluation of the circulatory system, ultrasonography, ultrasonocardiography, measurement of transdiaphragmatic pressures, scintiscanning of the lungs, spirometry, analysis of arterial blood gases, computed tomography of the thorax and external stimulation of the phrenic nerve were performed. The measurement of transdiaphragmatic pressure was crucial to establish and confirm the diagnosis of BDP, as only a small difference in gastric and oesophageal pressures during tidal breathing and inspiratory efforts was recorded. As no cause of diaphragmatic paresis was found, the case was classified as idiopathic. The final diagnosis of non-trauma related bilateral diaphragmatic weakness was generally delayed. In the case of the described patient, dyspnoea, the main symptom he was suffering from, was supposed to result from his congenital heart defect. We recommend that the suspicion of idiopathic diaphragmatic paresis should always be raised in patients suffering from respiratory failure of unknown origin. It is, however, necessary to perform extensive diagnostics to exclude the other causes of phrenic-diaphragmatic impairment. It's also necessary to consider all infections, injuries and surgical procedures within the thorax as possible causes of diaphragmatic paresis.