ANSWER:
The final diagnosis was pulmonary alveolar proteinosis.
DISCUSSION:
Introduction:
Immunocompromised children with pulmonary infiltrates are a difficult clinical challenge for several reasons. They often have high morbidity and mortality rates with an approximate 50% mortality in BMT (Bone marrow transplant) patients who develop bilateral pulmonary infiltrates. Difficulties can arise in the identification of the etiology of the process and empiric therapy does not always result in clinical improvement.
Initial investigations are often non-invasive and include radiography (Chest xrays, CT Scans), sputum cultures (including induced sputums), nasal washings for viral cultures, antigen and antibody detection and pulmonary function tests. When a diagnosis is not reached, more invasive investigations are required. These include gastric aspirates, bronchoscopy and bronchoalveolar lavage (BAL), transbronchial biopsies (although its role has been largely limited to lung transplant patients in pediatrics), transthoracic needle aspiration biopsies (which may have a high complication rate without CT or fluoroscopy guidance) and open lung biopsies (OLB).
Open lung biopsies have been considered the "Gold Standard" for the diagnosis of pulmonary disease in immunocompromised patients. However its exact role and clinical benefit is debated. To date there only retrospective non-controlled case series looking at open lung biopsies in immunocompromised children. The diagnosis and therapeutic benefits vary based on the population selection. The optimum timing of the procedure is not clear and there is often reluctance in proceeding due to the concerns regarding the risk versus benefit.
Since 1980, there have been about 16i published retrospective case series of open lung biopsies in immunocompromised patients. The number of patients in each series ranged from 12 to 56 for a total of 554 patients. A "definitive diagnosis" was reported in 36% - 94% of cases. Treatment change occurred in 55% - 90% of cases and an estimated benefit was reported in 10% - 46% of cases. Complication rates were reported in 4% - 52%. There was a wide variety of definitions used for the definitive diagnosis with clinical benefits and complications making direct comparisons difficult. For example, the definitions of benefit varied from clinical improvement after a change in therapy to avoidance of mortality after a change in therapy.
The diagnosis obtained depended on the underlying disease of patient and the years the study was performed. The initial case series (1980-1986) were on patients with malignancies and PCP was the most common diagnosis (a diagnosis was obtained 40-78% of the time). In more recent case series, the majority of the diagnoses were non-infectious. The most common infectious etiologies were Aspergillus, CMV and PCP.
Next page / / References