Systemic thickening of capillary endothelial basement membrane underlies the chronic complications of human diabetic microangiopathy. Since 99mTc-DTPA aerosol scintigraphy is a sensitive, non-invasive test of membrane permeability, we decided to study the effect of diabetes on the permeability of lung epithelium in diabetic patients using this test. Fifty (NIDDM) patients, aged 40-70 years, with or without complications, and who were non-smokers, were subjected to evaluation using 99mTc-DTPA aerosol. At the same time, pulmonary function tests, including carbon monoxide diffusion capacity, were done. Normal non-smoking subjects with no history of cardio-respiratory disease, who underwent 99mTc-DTPA and pulmonary function tests, served as controls. The risk factors which included age, sex, degree of control and presence of complications were noted. Twenty-nine (58%) of the patients had abnormal 99mTc-DTPA clearance. Thirty-four percent of the patients with complications and 24% of those without complications had abnormal clearance. Complications recorded included retinopathy, neuropathy and nephropathy. Fifty-five percent of patients with abnormal 99mTc-DTPA had suffered from diabetes for longer than 10 years. Sixty-two percent of patients with poor glycaemic control had abnormal 99mTc-DTPA. Diffusion capacity was not significantly affected in patients with complicated diabetes. Our preliminary results suggest that 99mTc-DTPA is a potentially sensitive test in assessing the degree of lung affection in diabetic patients. No significant correlation exists between diffusion capacity and 99mTc-DTPA. The risk factors did not affect the 99mTc-DTPA clearance, probably due to the small sample size.

Background: Many non-pulmonary physicians in hospital and family care practice base the diagnosis of pulmonary disorders on clinical impressions made from the history and physical examination. Experience has shown that relying on these parameters alone is not adequate, since this may result in missing a significant number of diseases, or in the unnecessary treatment of others. This study set out to compare the sensitivity, specificity and positive predictive value of the clinical assessment (provisional clinical diagnosis or PCD) with the combined clinical assessment and other investigations, including pulmonary function test (PFT). Patients and Methods: One thousand and fifteen (1015) patients referred for PFT to the pulmonary function laboratory of a teaching hospital were involved in the study. The referring physicians were asked to fill a specially prepared form giving details of the patients' history and clinical assessment. The PFT was performed using an ErichJager Master Lab. Results: Analysis of the final diagnosis revealed that only 51% of patients with a pre-evaluation diagnosis of asthma were actually confirmed to have asthma after further tests. Similar findings of 59% and 52% of patients with chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis were observed, respectively. The positive predictive value of PÇD for asthma and lung fibrosis was 64.1% and 61.9%, respectively, while that for COPD was 74.2%. Conclusion: This study showed conclusively that the predictive value of provisional clinical diagnosis in the evaluation of pulmonary disorders is usually inadequate, and needs to be augmented with additional simple investigations such as PFT, in order to establish a more accurate diagnosis. Ann Saudi Med 1999;19(2):93-96.