Our Water in Crisis: Assessing and Treating Lead Poisoning

This article was collaboratively written by Florence Emeka, PharmD, and Ayesha M. Khan, PharmD, BCPS. Dr. Emeka received her Doctor of Pharmacy degree from Chicago State University College of Pharmacy in 2016.

Lead contamination in drinking water extends far beyond the city of Flint, Michigan, which declared a health emergency over a year ago after discovering elevated concentrations of lead in its water source.

A recent analysis from the US Environmental Protection Agency revealed that between 2012 and 2015, approximately 350 school and daycare centers failed lead tests a total of about 470 times. There have been tremendous efforts across the nation to uncover and rectify this issue, but it’s also important for health care providers to address the possible physiological effects and treatment options for overexposure to lead.

Lead toxicity is related to the uptake of lead into the major soft tissue organs. Because of physiological differences between adults and children, the rate of lead absorption varies 40% to 50% and 10% to 15%, respectively. Since pediatric populations can absorb up to 5 times more water-soluble lead than adults, they’re most susceptible to toxic blood lead level (BLL) exposure.^1,2

The CDC recommends public health action for children aged 1 to 5 years with BLLs >5 μg/dL. Currently, about half a million children in the United States met these criteria.³

Lead Poisoning Symptoms

Signs and symptoms of lead poisoning are variable and highly dependent upon duration of exposure.

Acute exposure is classified as lead poisoning that isn’t immediately recognized and presents with common symptoms like abdominal pain, constipation, joint pain, and headache. These “classic” symptoms make it easy to misdiagnose lead poisoning for other more common diagnoses.⁴

Chronic exposure is classified as a BLL range of 30 μg/dL to 70 μg/dL, which could be caused by chronic or recurrent lead exposures. This type of exposure is associated with symptoms such as myalgia, fatigue, irritability, insomnia, anorexia, impaired short-term memory, and difficulty concentrating.⁴

Any patient with lead toxicity can experience neurologic, hematologic, renal, gastrointestinal, and endocrine system damage. Even with these potential complications, however, many patients remain asymptomatic. Therefore, attaining a BLL is recommended for an accurate diagnosis in suspected patients.

Lead Poisoning Diagnosis

It’s important to diagnose lead poisoning as early as possible because most of the detrimental physiological effects are irreversible. If a BLL can’t be determined immediately, the following objective findings can be used to support a diagnosis of lead poisoning²:

• Lead flecks in abdominal radiographs
• Lead lines on long-bone radiographs

Lead Poisoning Treatment

The reversibility of lead poisoning depends upon the lead blood concentration and duration of lead exposure. Before treating a patient, a toxicologist or clinician experienced with chelation therapies should be consulted.

If your institution doesn’t have an identified provider, various government agencies are available for assistance, including:

• State health department lead programs
• Pediatric environmental health specialty units
• Local poison control centers (1-800-222-1222)

Chelation therapy is recommended for moderate to severe intoxication (BLL >45 mcg/dL).

In severe intoxication (BLL >70 mcg/dL), chelation therapy can be life-saving, especially in children. At this level, dimercaprol, a deep intramuscular injection, is recommended for treatment. The injection must first be dissolved in peanut oil because of its lack of stability in water.⁵

In children with severe intoxication, dimercaprol is recommended in combination with calcium disodium due to potential increased lead concentration in the central nervous system and increased intracranial pressure.⁵ It can be administered intramuscularly or intravenously.

For children with moderate intoxication (BLL 45 mcg/dL to 69 mcg/dL), the oral agent succimer (Chemet) is the recommended option, as it has a rapid absorption and is more tolerable than other agents. In cases of mild intoxication (BLL <44 mcg/dL), supportive care measures are recommended over chelation therapy.

In all suspected cases, the following actions are recommended⁵:

• Confirm the result with a BLL within 1 to 4 weeks
• Inform appropriate health authorities
• Examine the patient by performing a history and physical
• Establish any other exposure risks
• Measure complete blood count, serum iron, ferritin, and C-reactive protein to assess iron deficiency
• Perform a plain radiograph of the abdomen in children with pica or mouthing behaviors to assess for lead flecks or foreign bodies containing lead
• Provide gut decontamination for patients that qualify
• Provide parents with education
• Monitor BLL with a pediatric lead poisoning specialist

Pharmacist Preparedness

The Flint Water Crisis is ongoing. To date, the city’s water supply has been returned to the Great Lakes from the Flint River. Still, all damaged pipes haven’t been replaced, resulting in a continuous filtration of lead into the tap water in some areas.

The effects of this crisis can remain in the community for an extended period of time. The importance of pharmacist preparedness in an emergent situation such as this is paramount for our communities. Understanding the assessment, diagnosis, and treatment plans for affected patients will allow pharmacists to optimize patient outcomes.

In times like these, health care professionals are particularly at the forefront and will be sought out for consultation on both acute and chronic intoxications.

References

• Calello DP, Henretig FM. Lead. In: Hoffman RS, Howland M, Lewin NA, Nelson LS, Goldfrank LR. eds. Goldfrank's Toxicologic Emergencies, 10e. New York, NY: McGraw-Hill; 2015.
• Hanna-Attisha M, LaChance J, Salder RC, Schnepp AC. Elevated blood lead levels in children associated with the flint drinking water crisis: a spatial analysis of risk and public health response. Am J Public Health. 2016;106(2): 283-290.
• CDC. Lead. cdc.gov/nceh/lead/. Accessed February 26, 2016.
• Goldman R, Hu Howard. Adult lead poisoning. In: UpToDate. Elmore J (Ed). UpToDate. Waltham, MA. 2015.
• Hurwitz R, Dean L. Childhood lead poisoning: management. In: UpToDate. Mahoney M (Ed), Burns M (Ed), Drutz J (Ed). UpToDate. Waltham, MA. 2016.