A Multicystic Dysplastic Kidney (MCDK) is a congenital, renal, cystic transformation usually diagnosed perinatally with 1:1000 to 4,000 incidence1. The natural history of MCDK is disputed with involution1, enlargement and development of hypertension2, infection and malignant transformation reported in the literature. We describe the case of a 25-year-old chef in whom an occult MCDK was incidentally detected. He presented with a four month history of intermittent diarrhoeal episodes and left flank discomfort. He had been aware of a sensation of fullness in the flank for a number of years but had not sought medical investigation. He had noticed an increase in size and discomfort with the onset of diarrhoeal episodes. Medical history included Type I Diabetes Mellitus for thirteen years but had not attended a diabetic clinic for four years. Medications included Novorapid 8iu/10iu/8iu, glargine 22iu nocte and lisinopril 2 mg daily. Examination revealed elevated blood pressure (160/103 mmHg), and bilateral pre-proliferative retinopathy with neovascularisation. Abdominal palpation revealed a large left flank mass, confirmed on CT Abdomen and a DMSA scan demonstrated a non-functioning left kidney. Laboratory studies revealed striking polycythaemia (Hb 21 g/dL), elevated erythropoietin level 36 mIU/ml (normal range 625), HbA1c 12.2%, diabetic proteinuria (0.16 grams/24 hours) and glomerular hyperfiltration GFR 130 mls/min/1.73 m2. Preoperatively laser treatment and repeated venesection was required to manage worsening diabetic retinopathy and secondary polycythaemia. Following nephrectomy, stabilisation of retinopathy, normalization of haemoglobin and an improvement in hypertension control was observed. This case strengthens the arguement2 for removal of all MCDKs in childhood to prevent complications in adulthood.
1 Rabelo EAS et al. Conservative management of multicystic dysplastic kidney: clinical course and ultrasound outcome. Jornal de Pediatria 2005 81 (5) 400404.
2 Webb NJA et al. Unilateral multicystic dysplastic kidney: the case for nephrectomy. Archives of Diseases of Childhood 1997 76 3134.