The first clinical description of Balkan endemic nephropathy (1956) and its validity 35 years later.

A high prevalence of renal disease in Vratza, a district in north-west Bulgaria, was studied in 1950-54 by Tanchev at the district hospital. A particular unknown renal condition was described at local meetings in 1953 and was referred to as 'endemic Vratza nephritis' in 1955. The first clinical description of this new nosological entity, published by Tanchev and colleagues in 1956, was based on 664 patients hospitalized for renal disease. Of 296 with chronic nephritis, 17 died in hospital and 103 died a few days later at home, all with uraemia, to give a total of 40.5%. Peasants formed the majority of the patients (85.7%), and 4-43 came from only 16 villages and 1-3 from 36 villages; none came from the remaining 21 villages in the district. Clusters of patients were thus noted in villages, families and even houses. The patients had the following common characteristics: from endemic areas; other renal ailments in the family; copper-yellow skin and orange palms and soles; normochromic anaemia; absence of acute onset, considerable albuminuria, hypertension and oedema; no compensatory polyuria; azotaemia progressing insidiously to fatal uraemia; 83.5% died within one year of the appearance of symptoms. After similar ailments were described in Yugoslavia in 1957 and Romania in 1961, the condition became known as Balkan endemic nephropathy. The etiology of this disease remains unknown, and no treatment is available, although haemodialysis and kidney transplants have prolonged patients' survival.