Treatment of Infection Due to Pneumocystis carinii

The therapy of infection due to Pneumocystis carinii has evolved in two areas over the past 20 years.First, improvements in the diagnosis of Pneumocystis infection have facilitated early diagnosis; treatment can often be initiated before marked deterioration in pulmonary function is observed.Second, the prolonged survival of immunocompromised patients has altered the presentation of Pneumocystis pneumonia, with there being an increased incidence of patients presenting with, in addition to P. carinii, multiple opportunistic infections often with some degree of resistance to common antimicrobial agents; the development of atypical (e.g., extrapulmonary) presentations of disease; and a growing number of patients requiring alternative prophylactic regimens due to drug toxicity (19a).Because Pneumocystis infection can be rapidly progressive and the success of therapy is related to the severity of disease at the time of the initiation of therapy, early therapy is essential.The short-term use of treatment (48 h) will not impair the histopathologic diagnosis of infection if, for example, bronchoscopic or laboratory support services are temporarily unavailable.The risk of opportunistic infection may be reduced by decreasing the level of immune suppression in patients receiving exogenous immune suppression for autoimmune diseases or following organ transplantation or by decreasing the viral load in patients infected with human immunodeficiency virus (HIV).Treatment of Pneumocystis should be successful if a 14-to 21-day course of therapy is tolerated. CLINICAL PRESENTATIONA number of atypical clinical features may alter the choice of therapy for Pneumocystis infection.Multiple infections are often present simultaneously with Pneumocystis infection.Multiple infections are often present simultaneously with Pneumocystis infection.Thus, failure to respond to appropriate anti-Pneumocystis therapy may reflect the progression of another process which may require treatment before clinical improvement is observed.Response to appropriate therapy may be slow.Response to appropriate therapy may be slow, especially in those with severe respiratory compromise or concurrent underlying lung disease.Radiologic appearance lags behind clinical deterioration or improvement.Radiologic appearance lags behind clinical deterioration or improvement, most commonly in the patient with altered pulmonary parenchyma due to radiation therapy, chemotherapy, or prior surgery; or in the patient receiving corticosteroid therapy; or in the patient with neutropenia.Empiric therapy is generally avoided in the immunocompromised host without AIDS.Empiric therapy is generally avoided