A Clinical Review of Acute Respiratory Distress Syndrome (ARDS) Due to Miliary Tuberculosis

Ahn, Young Soo; Lee, Sang Moo

Abstract

BACKGROUND: The detection and early elimination of the causes for acute respiratory distress syndrome (ARDS) at the initial stage can result in a more favorable prognosis. Miliary tuberculosis as a cause of the ARDS is quite rare. A diagnosis of miliary tuberculosis is difficult due to the diversity of radiological patterns and non-specific clinical findings, and low sensitivity of sputum examinations for acid-fast bacilli(AFBs). An analysis of the clinical data is the first step in diagnosing these unusual, rare cases. METHODS: In this study the clinical features, laboratory data, radiological findings and diagnostic methods were analyzed in 9 cases with an initial presentation of ARDS due to miliary tuberculosis. The ARDS was defined by the definition of the American-Europian Consensus Conference 1992. RESULTS: The mean age of the patients was 67+/-18 years (F:M=7:2). The chief complaints were dyspnea (5/9), coughing (3/9) and fever(5/9). On a physical examination, fine or coarse crackles were noted(6/9). The ARDS developed on average 6.7 days after the initial respiratory symptoms. The mean PaO2/FiO2 of the patients was 133.5+/-53.4, the number of cases with a WBC <5000/mm3 was 4 out of 9 cases. A platelet count <70,000/mm3 was observed in 2 out of 9 cases, and the serum albumin level was 2.6+/-0.6 g/dL. The initial simple chest PA showed ground glass appearances and consolidation in all cases, However, the miliary nodular densities were observed in only 4 out of the 9 cases. HRCT revealed alveolar densities and a consolidation in 5 out of 6 cases, and miliary nodules in 5 out of 6 cases, The diagnosis of tuberculosis was made by a liver biopsy (4/4, 100% sensitivity), a bone marrow biopsy (1/2, 50% sensitivity), and an open lung biopsy (1/1), the sputum AFB was positive in only 2 out of 9 cases. The patient was treated with INH, RFP, EMB, PZA, and steroids. The survival rate was 55.5%. CONCLUSION: Miliary tuberculosis should be considered as one of the causes for ARDS in areas where there is a high prevalence of tuberculosis. The chief complaints of the patients on admission are dyspnea, fever and coughing without any specific riskfactors. A liver biopsy is particularly useful in ARDS patients with mechanical ventilation to determine the causes of the ARDS if miliary tuberculosis is suspected as being the underlying disease.