Exhaled carbon monoxide in sarcoidosis.

BACKGROUND: Exhaled Carbon monoxide has been proposed as a non-invasive marker in several inflammatory diseases of the lung, but no data are available in patients with sarcoidosis. METHODS: We evaluated the levels of exhaled CO in 78 nonsmoker patients with sarcoidosis and we compared the results with 25 healthy non smoker controls, of 25 patients with a variety of interstitial lung diseases, and 77 smokers. RESULTS: Mean value of exhaled CO in sarcoidosis was 3.3 (2.9-3.8) ppm (GM with 95% CI in parenthesis), resulting significantly higher than both normal controls, 1.4 (1.2-1.7) ppm (p<0.001), and clinical controls, 2.1 (1.7-2.7) ppm (p<0.02). All these levels, however, were markedly lower than those observed in smokers, 14.6 (12.7-16.9) ppm. No correlation was found with radiological stage, steroid therapy, respiratory function, or serum ACE activity. Using an upper normal value of 4 ppm, an increased level of exhaled CO was found in 50% of patients with sarcoidosis, in 24% of clinical controls, and in 97% of smokers. CONCLUSIONS: Our data indicate that significant release of endogenous CO occurs in sarcoidosis. It is unlikely that the measurement of exhaled CO could be of diagnostic usefulness, due to its low specificity and to the possible influence by occasional or passive smoke.

Increased lung surfactant phosphatidylcholine in patients affected by lysosomal storage diseases.

Sandhoff disease, Gaucher disease type I and sialidosis type I are lysosomal storage disorders caused, respectively, by deficiency of activity of beta-hexosaminidase (storage of GM(2) and GA(2) ganglioside), glucosylceramidase (storage of glucosylceramide) and alpha-neuraminidase (storage of glucopeptides and/or oligosaccharides). Progressive clinical systemic and neurological dysfunctions are observed. In these pathologies, respiratory infections often lead to death. Elevation of the lung surfactant phosphatidylcholine (PC) has previously been reported in the Hexb mouse, a model of Sandhoff disease. We evaluated phospholipids in the lung surfactant of patients affected by the described lysosomal diseases, observing a statistically significant increase of total lipid phosphate in the patients as compared with controls. Moreover, higher levels of PC in patients affected by sialidosis (3.6-fold) and Gaucher (4-fold) disease, and of PC (4.15-fold) and phosphatidylethanolamine (2.3-fold) in a patient affected by Sandhoff disease were noted. The latter confirms the previous results in the Hexb mouse. We suggest that changes in phospholipid metabolism can be common in different lysosomal storage disorders and can increase the susceptibility to respiratory infections, usually present in these disorders.

Perception of dyspnea during exercise-induced bronchoconstriction.

UNLABELLED: After strenuous physical exercise, many subjects show a significant bronchoconstriction and report dyspnea. Despite this clinical condition being a commonly encountered situation during daily life, which may be responsible for substantial disability there is little information on the relationship between the perception of dyspnea and exercise-induced bronchoconstriction (EIB) after a standardized exercise challenge. For these reasons, we evaluated 200 consecutive outpatients (median age 13 years, ranging from 5 to 56 years) referred to our laboratory to perform an exercise test out of suspicion of EIB. On exercise challenge, perception of dyspnea was rated on a modified bipolar Borg scale immediately before each FEV1 measurement. Sixty-nine (35%) subjects had a positive exercise challenge, defined as a decrease of at least 20% in FEV1 from baseline. Both the onset and the decay of dyspnea preceded those of bronchoconstriction. Overall, the rating of dyspnea in the laboratory was well related with the reports of exercise-related symptoms. Similarly, 36 of 77 (47%) asthmatics with a history of exertional symptoms and 24 of 65 patients (40%) without a history had a positive challenge. Asthmatics reporting exertional symptoms perceived a greater magnitude of dyspnea after exercise independently from the degree of bronchoconstriction. Overall, dyspnea was significantly but loosely correlated to the magnitude of decrease in FEV1, being also influenced by age, gender and BMI. CONCLUSIONS: We conclude that dyspnea recorded in the laboratory after exercise test is related to exertional symptoms reported during real life, but not completely related to EIB. The rating of dyspnea is a well-suited model to study naturally occurring exercise-induced dyspnea and a useful tool to enlarge the results of an exercise challenge.