A KIDNEY BIOPSY IS CLEARLY MANDATORY TO CONFIRM THE INDICATION OF PLASMA EXCHANGES IN ADULT HEMOLYTIC-UREMIC SYNDROME

In case of haemolytic uraemic syndrome, it is not always possible to i dentify on a pure clinical basis the different kidney lesions responsi ble for the syndrome. We report a series of six cases without thrombot ic microangiopathy, which emphasizes the need to perform a kidney biop sy as early as possible, so as to confirm the actual usefulness of pla sma exchanges (PE) commonly carried out in emergency in every case of adult haemolytic uraemic syndrome. Patients and methods. - Files of pa tients who were treated for haemolytic uraemic syndrome over the past 14 years were reviewed. Patients in whom thrombotic microangiopathy ha d been excluded by renal histology data were studied. Every patient wa s promptly treated with hypotensive drugs, so as to obtain blood press ure levels not exceeding 160-90 mmHg. Dialysis was performed in two pa tients. Daily PE with fresh frozen plasma were carried out in three pa tients as early as the first 24 hours after admission, and discontinue d immediately after thrombotic microangiopathy could be excluded. Resu lts. - All the patients met the usual criteria for diagnosis of haemol ytic uraemic syndrome. Elevated liver enzymes were also found in the f our cases of preeclampsia, consisting with diagnosis of severe HELLP s yndrome. One case was associated with oestrogen therapy. Glomerular le sions were seen in four patients: slight endotheliosis in three cases of preeclampsia; marked lesions of IgA mesangial deposits in the patie nt who had been treated by contraceptive pill. Three patients had acut e tubular necrosis and three had intense lesions of nephrosclerosis. C omplete remission was obtained in every case of preeclampsia. Renal fa ilure persisted in two cases (IgA glomerulopathy and one case of nephr osclerosis). Discussion. - The histological heterogeneity of haemolyti c uraemic syndrome has been already well demonstrated. Typical lesions of thrombotic microangiopathy are usually classified into predominant glomerular lesions, pure arteriolar and mixed lesions. In other cases , thrombotic microangiopathy is not found: kidney lesions may be glome rular (endotheliosis, various subtypes of glomerulonephritis), tubular (acute tubular necrosis) or vascular (nephroangiosclerosis). In every aetiological circumstance, several different lesions may be found tog ether. The usefulness of PE has been proved in thrombotic thrombocytop enic purpura, has been suggested in haemolytic uraemic syndrome and to a lesser extent in persistently severe HELLP syndrome. Unfortunately, none of these reports gave any information about kidney lesions respo nsible of acute renal failure. Conclusion. - The haemolytic uraemic sy ndrome is a syndrome: thrombotic microangiopathy has to be proven when treatment by PE is planned, except in some severe clinical circumstan ces.