Introduction:

Acute respiratory distress syndrome (ARDS) is characterized by the acute onset of illness, bilateral chest radiographic infiltrates consistent with pulmonary edema, and poor systemic oxygenation. ARDS has severe morbidity and mortality. The most common risk factor for the development of community-acquired ARDS is severe sepsis with a pulmonary source of infection. The first step in the therapy of ARDS is identification and treatment of the underlying disease. Here, we report two cases of ARDS associated with Legionnaires disease.

Case 1:

A 54-year-old male tourist with diabetes mellitus apply to our institution with diarrhea and high fever. At the time of admission, the patient had a temperature of 39.5°C, a blood pressure of 140/70 mmHg, a heart rate of 102 beats/min and a respiratory rate of 24 breaths/min. His oxygen saturation was 93% while breathing room air. Chest examination revealed rales and the chest x-ray showed right-lower zone infiltrates. Legionella urinary antigen was positive on admission day. Treatment with levofloxacin (1000 mg/day) was started in the first 4 hours of admission after taking cultures. The patient had progressive dyspnea and cyanosis was developed. Analysis of arterial blood gas revealed a pH of 7.29, CO₂ pressure of 30 mmHg, O₂ pressure of 37 mmHg and oxygen saturation of 62%. Roentgenogram of the chest worsened and showed bilateral infiltration, indicating ARDS. Thirty-two hours after admission, the patient was admitted to intensive care unit for ventilator support. The patient’s clinical status continued to deteriorate. He was hypotensive and required dopamine infusions for blood pressure support. Legionella pneumophila serogroup 1 was isolated on sputum culture. Five days after hospitalization, chlarithromycin (1000 mg/day) and ciprofloxacin (1200 mg/day) were substituted for the initial antibiotics. The patient had nosocomial pneumonia caused by methicilline resistant Staphylococcus aureus during subsequent days. Vancomycine 2 gr/days was added to treatment. Clinical status improved and the body temperature fell below 37.5°C on the eleventh day. On the patient’s relatives’ request, he was flown back to his country by air ambulance. One year later, the patient came back again as a tourist and had fully recovered from the illness.

Case 2:

A 82-year-old female with diabetes mellitus applied to our institution with high fever, dyspnea and mental change. She had been treated for pulmonary edema without any response to this therapy in a private hospital. She had been hospitalized in another hospital due to gastrointestinal bleeding approximately two weeks prior to her application. Chest examination revealed diffuse rales and the chest x-ray showed bilateral infiltrates. Analysis of arterial blood gas revealed pH of 7.31, CO₂ pressure of 41.7 mm Hg, O₂ pressure of 21.9 mmHg and oxygen saturation of 33.6%. The patient was admitted to intensive care unit for ventilator support. Legionella urinary antigen was positive on admission day. Treatment with ciprofloxacin (1200 mg/day) and chlarithromycin (1000 mg/day) was started on admission after taking cultures. Legionella pneumophila serogroup 1 was isolated on endotracheal aspirate culture. The patient died on the 7^th day.

Conclusions:

The clinicians should be aware of Legionnaires disease in etiology of ARDS. Early diagnosis and treatment are important factors in determining prognosis.

Keywords: Legionnaires disease, Legionella pneumophila, pneumonia, respiratory distress syndrome