A 48-year-old male refugee from the Middle East complains of slowly worsening fatigue, sluggishness, and a lack of concentration over a period of three to four years. Careful questioning reveals a history of intermittent vague lower back pain for the same duration. He has experienced recurrent episodes of urinary frequency and dysuria since childhood. He says that these were 'only treated with pills', and it appears that they were not investigated further, due to his socioeconomic status. He does not drink but has smoked heavily, to a total of 10 pack years. A complete blood count is significant for a hemoglobin of 9.6 g/dL, with a subsequent blood film demonstrating normocytic normochromic anemia. A tuberculin skin test is found to be negative.
The ultrasound scan reveals a small right kidney, measuring 6x3x2 cm (normal: 11x7x3 cm), with an irregular echotexture, cortical scarring, and an echogenic parenchyma. A staghorn calculus is visualized in the right pelvis, with hydronephrosis. The left kidney appears normal. There are no perirenal fluid collections or obvious anatomic abnormalities of the genitourinary system.
RBC: 2-3/hpf (2-3) Pus cells: 50-60/hpf (0-4) WBC casts: present Nitrates: negative Proteins: 1+ Cultures: positive for Proteus spp., sensitive to ampicillin and cephalosporins.
BUN: 16 mg/dL (7 - 20) Serum creatinine: 1.0 mg/dL (0.6 - 1.2) Estimated GFR: 92 mL/min/1.73 m2 (90 - 120) Na+: 136 mEq/L (135 - 145) K+: 4.5 mEq/L (3.5 - 5.3)
A small right kidney with a unilateral staghorn calculus is visualized. No other abnormalities are seen.