The Rainy Season Abscess

A 51-year-old man from rural northeastern Thailand presents to a provincial hospital in September with 3 weeks of intermittent fevers, drenching night sweats, diffuse myalgias, and a progressively enlarging painful swelling on his left flank. He works as a rice farmer and spends long hours barefoot in flooded paddies during the monsoon season. He was diagnosed with type 2 diabetes mellitus 6 years ago but has been inconsistently adherent to metformin and has not seen a physician in over a year.

One week prior to presentation, the flank lesion was incised and drained at a local clinic. He was prescribed dicloxacillin 500 mg four times daily. Despite this, he has continued to worsen, with new-onset rigors, productive cough, and significant malaise over the past 3 days prompting hospital referral.

On examination he appears acutely ill. Temperature is 39.8°C, heart rate 128 bpm, blood pressure 108/62 mmHg, respiratory rate 28 breaths per minute, and oxygen saturation 93% on room air. He is pale and mildly jaundiced. The left flank has a 5 × 3 cm area of erythema and fluctuance with purulent drainage from a central wound. There is no regional lymphadenopathy. Chest auscultation reveals bilateral basilar crackles with reduced breath sounds on the right. The abdomen is soft without palpable organomegaly.

Laboratory studies show WBC 18.4 × 10⁹/L with 89% neutrophils, hemoglobin 11.8 g/dL, platelets 98 × 10⁹/L, random glucose 22.3 mmol/L, AST 148 U/L, ALT 96 U/L, total bilirubin 89 μmol/L, and creatinine 72 μmol/L. Blood cultures and a deep wound swab are sent. Chest radiograph shows bilateral pleural effusions with patchy airspace opacities in the right lower lobe.