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.

Geographic correlation between the occurrence of endemic nephropathy and urinary tract tumours in vratza district, Bulgaria.

Data on the occurrence of endemic nephropathy (EN) and urinary tract and other cancers in an endemic region of Vratza district, Bulgaria, for the years 1965-1974, are presented. In endemic villages a high incidence of urinary tract tumours, affecting in particular the renal pelvis and ureter, closely correlated with the EN incidence and mortality rates. In the villages with high and moderate EN incidences urinary tract tumours are the most common neoplasms. They account for 25% of all tumour sites in males and 30% in females. In hyperendemic villages age-adjusted incidences in EN and urinary tract tumours were 506/10(5) and 104/10(5) in females, and 315/10(5) and 89/10(5) in males respectively. EN mortality in these villages accounted for over 40% of all deaths in females and about 30% in males. Both diseases displayed peculiar geographic clustering. Females and middle-aged persons were most often affected. Urinary tract neoplasms were often multiple and nearly 90% of them originated in the uro-epithelium. In endemic and non-endemic villages of the region studied, the frequency and pattern of non-urinary tract cancers were rather similar, with statistical values close to those of the rural population of Vratza District and Bulgaria as a whole.