Idiopathic retroperitoneal fibrosis: a rare onset of the illness caused by haemorrhagic fever with renal syndrome.

Sir, Idiopathic retroperitoneal fibrosis (IRF) is a collagen vascular disease of unknown aetiology. It is characterized by chronic, non-specific retroperitoneal inflammation, which may cause ureteric obstruction. Many authors believe that it is a type of immune disorder [1]. Bosnia and Herzegovina is known as a region where Hanta virus infection has been endemic for >50 years [2]. A case of IRF associated with haemorrhagic fever with renal syndrome (HFRS) has not been reported up to now. A 44-year-old, previously healthy man was hospitalized with acute renal failure. He was febrile 2 days before admission, had dull abdominal pain, decreased urine output, shortness of breath, diarrhoea and arterial hypertension (190/120mmHg). Blood tests showed metabolic acidosis (HCO3: 15.9mmol/l) and increased C-reactive protein (11.26mg/l), potassium (7.9mmol/l), serum creatinine (884 mmol/l), blood urea nitrogen (17.6mmol/l) and globulins (49.1 g/l) and decreased haemoglobin (7.4mmol/l). Urinanalysis showed proteinuria and leukocyturia. Urine culture was negative. Indirect immunofluorescene tests for Hanta viruses were positive for Pummala virus. Ultrasound showed acute renal parenchymal lesions with bilateral hydronephrosis, grades I–II, and widening of the wall of the abdominal aorta. The presence of a great number of rodents in the forest where the patient was working has been reported by the epidemiology service. After supportive, antihypertensive and diuretic therapy, the patient’s renal function stabilized, with serum creatinine at 187 mmol/l and potassium at 4.5mmol/l. Intravenous urography showed a functioning left kidney, with a suspected retrocaval ureter on the right side and dilation of the channels of the right kidney. A computed tomography contrast scan showed a solid retroperitoneal mass, in the form of thick plate of high density, extending from the level of the renal hilum down caudally to the bifurcation of the aorta (compatible with retroperitoneal fibrosis). A double-J stent was applied and steroids and androgens were administered (pronison 60mg plus tamoxifen 20mg 2). After 3 months, the stents were removed and medications were continued. After 6 months, the patient’s total DTPA clearance was 61.1ml/min (11.8ml/min in the left kidney and 49.3ml/min in the right kidney), measured by technetium marked by diethylaminoacid. Steroids and androgens were withdrawn after 12 months. The patient has normal blood pressure and stable renal function, with serum creatinine at 125mmol/l. It remains a mystery whether HFRS triggered an immune abnormality and acceleration of the symptoms of a latent IRF or whether the two diseases merely coincided. Adequate treatment of HFRS was certainly the reason that renal function recovered and the progression of the disorder caused by the chronic disease, IRF, was hampered.