1 Department of Renal Medicine 2 Department of Radiology 3 Scottish Liver Transplant and Renal Transplant Unit Lothian University Hospitals NHS Trust UK
Case
A 47-year-old renal allograft recipient presented 14 months post-transplant with anuria, of sudden onset. He had autosomal dominant polycystic kidney disease (ADPKD) and had been on hospital haemodialysis for 3 years prior to transplantation, when he received a live unrelated renal allograft from his partner. The graft was a 1,2,2 mismatch and his immunosuppression was tacrolimus (5 mg/day) led triple therapy with azathioprine (75 mg/day) and prednisolone. His immediate post-transplant function was good (Table 1), but at day 21 he had a deterioration in function and required a diagnostic renal transplant biopsy. Two samples were taken from the medial pole under real-time ultrasound guidance and histological examination revealed acute cellular rejection (Banff grade 1). He had no haematuria or drop in haemoglobin post-biopsy. The deterioration in renal function reversed after treatment with methyl prednisolone. Following this episode graft function remained stable, with a blood urea of 8.8 mmol/l and creatinine of 139 µmol/l and normal blood pressure on a single anti-hypertensive agent (betablocker) at routine review, 13 months post-transplant, just prior to his current presentation.
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On presentation he was very anxious regarding his graft function. He was hypertensive at 150/110 mmHg and had no increase in temperature. His graft in the left iliac fossa was enlarged and tender, his plasma creatinine had risen to 311 µmol/l (Table 1) and his bladder was empty. Emergency investigations were undertaken.
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Ultrasound with a Doppler examination and CT scan (Figure 1a, b
and c
) demonstrated a dense perinephric collection, suggestive of haematoma over the lateral aspect of the transplant kidney with displacement of the hilum anteriorly and medially. The vascular supply to the kidney was preserved but compressed. Given these findings, he was prepared for theatre and consented exploration of the graft and possible graft nephrectomy.
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Discussion
This case demonstrates an acute bleed which occurred within the fibrous pseudocapsule and caused renal dysfunction in a renal allograft of 14 months, with full reversal of function on evacuation of the haematoma. This haematoma occurred in the absence of any definite history of injury. However, our patient had carried out heavy strenuous exercise in the days preceding the bleed. It seems likely that this resulted in the spontaneous pseudocapsular bleed. Renal allografts are superficially placed in the iliac fossa and all patients are cautioned regarding contact sports. Despite this, there are very few case reports describing non-biopsy related renal allograft injury, indeed any injury reported seems to follow blunt trauma to the anterior abdominal wall.
Spontaneous renal rupture was frequently described in the early years of transplantation, it is nearly always associated with severe early rejection and is now rarely seen [1,2]. There is one report of a lymphocoele occurring in an established renal allograft, following a squash ball induced blunt injury [3]. A further two case reports have described seat belt compression injuries presenting late with hypertension and a rise in creatinine. One of these cases documents a lower pole infarct [4] and the other resulted in a lymphocoele of the transplant [5]. A case of anuria in a renal allograft following blunt trauma to the abdomen demonstrated an extensive subcapsular haematoma, with recovery of renal function following evacuation [6]. In 1939, Page described an experimental model of wrapping cellophane around the renal capsule resulting in a tight fibrous sheath around the kidney, leading to hypertension and impairment of function due to increases in intrarenal pressure [7]. This has been described in native kidneys following blunt trauma and is known as Page kidney [8].
In a renal allograft, there is a risk of spontaneous subcapsular bleeding which may be brought on by strenuous exercise. Renal allografts are particularly prone to this phenomenon due to the formation of a tight fibrous pseudocapsule which seems to occur universally following graft insertion, and seems to be a similar mechanism to the fibrous encasement of a foreign body. This case illustrates that in a patient with stable graft function who presents with oligo/anuria for which no obvious cause is apparent, the possibility of subcapsular haematoma should be considered with urgent evacuation of the capsule if renal function is to be restored.
Notes
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References