Spontaneous rupture of an infected renal cyst and external drainage through a lumbar surgical scar in a male patient with cervical spinal cord injury: a case report

INTRODUCTION The spontaneous rupture of an infected renal cyst is a rare event. Spontaneous rupture with drainage to the exterior through a surgical scar has not been reported previously. CASE PRESENTATION A 49-year-old male with tetraplegia had undergone extended right pyelolithotomy in 1999. Deroofing and marsupialisation of a cyst in the upper pole of the right kidney was performed in 2003. Subsequently there was recurrence of a thick-walled cystic space-occupying lesion in the upper pole of the right kidney. Thick pus was aspirated from the renal cyst on six occasions between September 2003 and November 2004. In March 2006, ultrasound examination revealed a cyst measuring 6.2 cm in diameter in the upper pole of the right kidney. Aspiration was planned when the renal cyst reached 7.5 cm in diameter. However, 11 months later, the cyst ruptured spontaneously and drained through the previous surgical scar in the flank, while the patient was recovering from a severe chest infection in the spinal unit. Ultrasound examination showed a fistulous tract running between the renal cyst and the abdominal wall. Repeated minor trauma sustained during turning, hoisting and chest physiotherapy all may have contributed to the rupture of the infected renal cyst and drainage through a weak spot in the abdominal wall. CONCLUSION In hindsight, we might have prevented rupture of the renal cyst had we considered aspiration of the renal cyst before it reached 7.5 cm in diameter, although this 7.5 cm diameter, as the threshold for percutaneous aspiration, is an arbitrary setting. This patient could have been advised to wear an abdominal corset to protect the right flank from pressure applied unintentionally during turning, hoisting or assisted coughing.