Leptospirosis, American Samoa

To the Editor: Leptospirosis is common in the Pacifi c Islands (66.4 cases/100,000 population/ year compared with 5 cases/100,000 population/year globally) (1) and is often misdiagnosed as dengue because of overlapping clinical features, poor awareness, and inadequate diagnostic facilities (2,3). Clinical manifestations range from asymptomatic to severe disease with pulmonary hemorrhage and renal and hepatic failure. Global emergence of leptospirosis has been associated with environmental factors including rainfall, fl ooding, poverty, urbanization, and ecotourism (1–4), to which the Pacifi c Islands are vulnerable. Seroprevalence of leptospirosis in American Samoa is 15.5% (5), and recent reports confi rm its emergence in the Pacifi c region (6). We report a case of severe leptospirosis in American Samoa (one of the world's wettest inhabited places) and illustrate diagnostic challenges and the need to improve laboratory capacity. In January 2011 (wet season), a 15-year-old previously healthy Polynesian boy was examined for a 3-day history of fever, myalgia, fatigue, headache, sore throat, pleuritic chest pain, and vomiting. He spent much time outdoors, occasionally slept in the rainforest, and had recently waded through water. Examination revealed lethargy, injected conjunctivae, mild periumbilical tenderness, fever (38.6°C), tachycardia (133 beats/ minute), and hypotension (96/50 mm Hg). Lung sounds were clear, respiratory rate was 22 breaths/minute, and oxygen saturation was 99%. No rash or jaundice was noted. Laboratory investigations showed leukocytosis (9.35 × 10 9 cells/L), neutrophilia (85%), mild normocytic anemia (12.0 g/dL), and thrombocytopenia (42 ×10 9 platelets/L); chest radiographs showed mild infi ltrate in the left lung. Differential diagnosis included dengue, infl uenza, pneumonia, and leptospirosis. The patient was hospitalized for supportive treatment, but the next day he experienced shoulder pain, increased abdominal and chest pain, worsened thrombocytopenia, hypokalemia, hyperbilirubinemia, proteinuria, hematuria, and fecal occult blood. No abnormalities were found for the following: transaminase, alkaline phosphatase, blood urea nitrogen, and creatinine levels; blood culture; serologic test results for hepatitis; and abdominal ultrasonogram. Intravenous penicillin was given for possible leptospirosis and/or pneumonia. Within 1 hour, the patient's condition deteriorated: temperature increased (40.2°C); and rigors, severe headache, and myalgia developed. Jarisch-Herxheimer reaction was considered (7), and intravenous penicillin was replaced with ceftriaxone. The patient deteriorated further and exhibited hypotension, tachycardia, tachypnea, jaundice, confusion, mucosal bleeding, and required intensive care treatment, including intravenous dopamine for shock. Repeat chest radiograph showed deterioration with bilateral infi ltrates. The Figure shows progression of kidney and liver function and thrombocytopenia. Serum collected on hospitalization day …