Melamine-tainted milk product (MTMP) renal stone outbreak in humans.

The ‘outbreak’ of renal stones associated with consumption of melamine-tainted milk products (MTMP) in infants and young children in China, is truly a disaster. By mid October 2008, 47 000 individuals were reported hospitalised with kidney problems related to MTMP-contaminated infant formula consumption, at least four of whom died.1 The outbreak occurred in many regions, but mainly in Ganzu, Henan, Ningxia, Hubei, Hunan, Anhui, Jiangsu, Jiangxi, Shaanxi, and Shandong provinces. Many of the stones were rather ‘loose’ and ‘soft’; and after copious water drinking, they could be passed out as sand and sediments, which made the urine slightly turbid and cloudy.1,2 The stones were radiolucent and could be detected by ultrasound. Seriously affected patients had urinary obstruction with acute renal failure, but many individuals with smaller stones were virtually asymptomatic and only picked up after ultrasound of the kidneys. Apparently the severity of the affliction was dose-related; the great majority being associated with the consumption of ‘Sanlu’ (三鹿) milk, which had very high melamine concentration (up to >2.5 g/kg). Large-scale ultrasound screening in China has resulted in the detection of thousands of stones of varying sizes, and resulted in variably severe to mild effects on the health of the respective infants and young children.