The recent news about lead exposure from city water in Flint, Michigan, has renewed many people's concerns about an environmental cause of kidney disease. For years, extraordinary efforts have been made to eradicate environmental lead exposure by eliminating lead based gasoline, stopping the sale of lead based paints, removing lead based paint from older homes, and monitoring of blood lead levels in children and the public by local health departments. All of these activities have resulted in consistently fewer reports of lead-associated kidney disease. Environmental exposure from lead in water has only recently been recognized as a public health hazard.
Let's refresh our familiarity with lead-induced illness from long term exposure.
Lead toxicity is usually recognized in two populations: young children and populations prone to chronic kidney disease (CKD). Lead exposure in young children is most often a result of ingesting lead in paint dust or chips or inhaling it through the air from leaded gasoline and associated environmental air pollution. This acute lead poisoning leads to neurologic toxicity (especially in developing brains and nerves) and is often associated with anemia and intellectual deficits that will only be apparent years later. This type of toxicity comes from high levels of exposure that is rare in the United States today with the reduction in the usual sources of environmental exposures such as air pollution and lead paint.
Long term chronic exposure to lead is more insidious and leads to subtle changes that are more difficult to recognize, as in the case of lead-associated kidney disease. Populations that are already prone to chronic kidney disease (CKD) seem to have greater long term toxicity from lead exposure. Lead is taken into the body through the lungs and the gastrointestinal tract, and can be slowly released into the blood stream, resulting in long term, low level toxicity. Patients with diabetes and hypertension who are prone to develop CKD are more likely to accumulate lead because of the body's inability to eliminate it through the kidneys. This type of kidney disease progresses more rapidly than it otherwise would and is known as interstitial nephritis. The common findings in patients with lead associated kidney disease are gout, high blood pressure and chronic anemia, in addition to the more rapid deterioration in kidney disease.
The most important treatment goals for lead-associated kidney disease is to eliminate the source of excess lead exposure and effectively treat the diabetes, high blood pressure and gout that may complicate the underlying kidney disease. Using agents to bind up lead from the body (chelation) is not commonly performed due to lack of studies that show this practice to be universally effective.
If you have CKD and think you might have been exposed to lead, it's important to determine the levels of lead in the blood and seek proper treatment by someone who is familiar with chronic lead toxicity. Your local Health Department can help you seek proper referral. Avoiding further exposure is paramount in the treatment regimen. You can also get more information about CKD at the National Kidney Foundation website.