Study objectives: We used invasive and noninvasive procedures to determine the causes of pneumonia in renal transplant recipients.
Subjects and methods: We retrospectively surveyed 565 renal transplant recipients (transplants received March 1984 to August 2001) to find those with pneumonia. Noninvasive diagnostic methods included serologic testing, and blood and sputum cultures with stains. Invasive procedures included fiberoptic bronchoscopy and percutaneous transthoracic procedures.
Results: A total of 92 patients were enrolled. Of these, 71 patients had a definite etiologic diagnosis of pneumonia. The major infectious pathogens were bacterial (n = 21) and mixed bacterial infection (n = 10), Mycobacterium tuberculosis (TB) [n = 18], and fungi (n = 8). Noninvasive and invasive procedures led to the diagnosis of pneumonia in 31.5% (n = 29) and 45.6% (n = 42) of patients, respectively. Bronchoscopy was used in 64 patients, with a diagnostic yield of 38 cases (59.3%). Patients were 3.62 times more likely to contract pneumonia within 12 months of renal transplantation than they were ≥ 12 months thereafter (95% confidence interval, 1.33 to 9.84). Twenty-seven of the 92 patients (29.3%) died. The pneumonia mortality rate has dropped significantly since 1996 (41.8% vs 10.8%, p = 0.002).
Conclusion: Both invasive and noninvasive procedures are useful in the diagnosis of pneumonia, with declining mortality, in renal transplant recipients. Bacterial and mixed bacterial infection, TB, and fungal infection are the most common pathogens; cases are most likely to occur within 1 year after renal transplantation.