A patient with limited systemic sclerosis for the past 10 years complaints of shoness of breath for the past one year. His pulmonary function tests are as follows - PFT OBSERVED PREDICTED FVC 2.63 2.82 FEV 1 88% 80% DLCO 5.2 16.3 Which among the following is the probable diagnosis

Pulmonary aery hypeension The forced vital capacity (FVC) is not decreased in this case. The forced vital capacity in the question is FVC 93% is normal. - (Any pulmonary. function test which is 80-100% of the predicted value is considered normal) The FEV I is also mentioned as normal. So, the only pulmonary function abnormality is decrease in DLCO. This strongly suggests pulmonary aery hypeension. - Systemic sclerosis is associated with both pulmonary aery hypeension and interstitial lung disease. - They are quite difficult to distinguish clinically because pulmonary, function test are almost similar. - Both presents with restrictive pattern of disease and decrease in DLCO. Features of pulmonary function test which ours pulmonary aery hypeension are : -- Decrease in DLCO in the absence of any other abnormality on pulmonary. test i.e., isolated decrease in DLCO. - Decrease in DLCO is out of propoion to the decrease in FVC. If FVC/DLCO ratio > 1.5 ---> Pulmonary aery hypeension < 1.5 --> Interstitial lung disease. The definitive diagnosis of : ? Pulmonary aery hypeension --> Pulmonary aery catheterization. Interstitial lung disease --> Helical CT scan In the question the patient shows decrease in DLCO in the absence of any other abnormality. This strongly suggests pulmonary aery hypeension.