An unusual case of nephrocutaneous fistula

Abstract

An 86-year-old Caucasian woman presented with a 2-day history of a painful swelling in the left upper thigh anteriorly. She also gave a recent history of recurrent urinary tract infection associated with macroscopic haematuria, against a background of a long-term indwelling catheter for complete urinary incontinence. She denied any change in bowel habit and her weight had also been stable. Her past history included a hysterectomy, dynamic hip screw insertion for fractured right neck of femur and coronary artery disease. On examination she was apyrexial with no signs of anaemia, jaundice or lymphadenopathy. The left thigh swelling was confirmed to be an abscess. Abdominal and rectal examinations were unremarkable. The abscess was subsequently incised and drained. A substantial amount of pus was released. Culture of the pus yielded Proteus and Escherichia coli. Unfortunately the left thigh wound failed to heal up completely resulting in a constantly discharging sinus (Figure 1). A sonogram was then performed which revealed a fistulous track passing closely to the left greater trochanter and then superiorly projected over the left iliac wing. It then tracked medially towards the spine and particularly towards a small staghorn-like calculus on the left side. At no time was contrast seen to spill intra-abdominally (Figure 2). A subsequent computed tomography scan demonstrated that the fistulous track lay anterior to the neck of femur and passed superiorly in front of the hip joint before entering the iliacus muscle compartment retroperitoneally. The contrast then tracked superiorly until it reached the iliac crest. It continued superomedially and retroperitoneally towards the lower pole of the left kidney which contained a staghorn-like calculus. Contrast was also seen in the bladder (Figure 3). The patient did not have intravenous pyelography. A diethylene triamine pentaacetic acid (DTPA) renogram was carried out which confirmed that the patient had a non-functioning left kidney but good function of the right kidney. This woman subsequently underwent a left nephrectomy through a midline incision. The left kidney was shrunken and tethered retroperitoneally, and was associated with a well-defined fistulous track. The track was opened and curetted and an associated abscess cavity involving iliacus muscle drained. Histology of the kidney confirmed chronic pyelonephritis with scarring and presence of calculus in the dilated pelvicalyceal system. The patient made a straightforward postoperative recovery. At follow-up 3 months postoperatively, the thigh sinus had healed completely and the patient was asymptomatic.