A 48-year-old man presents with intermittent fever for one week. The fever was low-grade initially, but became high-grade yesterday. He has had a dull ache in the left upper abdomen for the same duration. No other symptoms are present.

His medical history is significant for type 2 diabetes mellitus for eight years, with poor control, limited dietary compliance, and only occasional follow-up. Whether he has any complications of diabetes is undocumented. He experienced an episode of cystitis one month ago; this was the first urinary tract infection in his life. This resolved with antibiotic therapy. He defaulted on follow-up; and has not been evaluated for abnormalities of the urinary tract.

He is currently on Metformin 850 mg daily and Gliclazide 30 mg daily. He has no allergies. He drinks socially and does not smoke. There is no history of recreational drug abuse. Basic investigations show a leukocyte count of 16,500/mm3 (normal: 4,600-11,000), with 90% neutrophils; a capillary blood sugar of 225 mg/dL (12.5 mmol/L); and normal blood urea and serum creatinine levels.