Conclusion
This case highlights the risks and clinical manifestations of lead toxicity from Ayurvedic medicines and the importance of collaboration between clinicians and public health authorities to control the health risk from lead in consumer products. When consumer products may be contaminated with lead, or when lead exposure is linked to sources in the community, involving public health can facilitate broader actions to reduce and prevent exposures to other people at risk.
The section Cases presents brief case reports that convey clear, practical lessons. Preference is given to common presentations of important rare conditions, and important unusual presentations of common problems. Articles start with a case presentation (500 words maximum), and a discussion of the underlying condition follows (1000 words maximum). Visual elements (e.g., tables of the differential diagnosis, clinical features or diagnostic approach) are encouraged. Consent from patients for publication of their story is a necessity. See information for authors at www.cmaj.ca .
Discussion
Given that lead toxicity is uncommon and its presentation non-specific, patients are often seen by many health care providers before the diagnosis is made. A careful exposure history is essential to suggest the diagnosis. Lead toxicity should be considered in patients with abdominal pain and microcytic anemia, particularly if basophilic stippling is present. It should also be considered in patients with abdominal pain, headache, fatigue, new or worsening cognitive impairment and a suspicious exposure history. Making the diagnosis with a blood lead level can avoid extensive investigations for abdominal pain and anemia. Hair lead and urine lead levels, including from chelation-provoked urine analysis, are not clinically meaningful. 2
Ayurveda is a traditional Indian system of medicine that can include the use of herbal medications. 3 A nationally representative survey in the United States found that 1 in 1000 people had used Ayurvedic medicines in the previous year. 4 A random sample of Ayurvedic pills bought on the Internet from manufacturers based in the United States and India showed that 21% contained lead, mercury or arsenic. 5 Heavy metals are sometimes intentionally added for their perceived healing properties. 3 A recent systematic review of case reports on lead poisoning found traditional or herbal medications to be a common cause. 6 People can obtain Ayurvedic medicines by importing them privately; this circumvents regulated pathways that may flag products with toxic substances.
Lead exposure has decreased over the past 40 years given increasingly strict regulations on leaded gasoline and consumer products. Exposures to lead include contaminated food, drinking water, household dust, consumer products, air and soil, but these would not typically be expected to cause toxicity. 7 Lead toxicity in Canada is uncommon. 8 In 2018–2019, the geometric mean blood lead level in people in Canada aged 3–79 years was 0.81 μg/dL; the 95th percentile was 2.3 μg/dL. 7 Clinical symptoms become apparent at lead levels around 40–79 μg/dL. 2 In the toxic range, exposure is often from occupational or recreational sources ( Table 1 ).
Sources of lead that may lead to elevations in blood lead levels
Lead and nonferrous smelting and manufacturing 6 , 9 , 10
Battery manufacturing, repair and recycling 6 , 9 , 10
Welding 9
Automotive manufacturing and repair 6 , 9 , 10
Copper, nickel, lead, zinc and coal mining 6 , 10
Some types of construction (e.g., bridge construction) 9 , 10
Plumbing, heating and air-conditioning contracting 10
Making crystal glass 9
Polyvinyl chloride plastic manufacturing 9
Shooting guns with leaded munitions 6 , 9
Ceramic crafting 6 , 9
Furniture refinishing 9
Home refinishing 9
Painting (fine artist’s pigments) 6 , 9
Repair of automobiles or boats 6 , 9
Making stained glass 6 , 9
Retained bullets or pellets 6
Contaminated substances of abuse 6 , 9
Paint chips 6
Folk, traditional or herbal remedies 6
Clinical symptoms of lead toxicity occur in a dose-dependent manner, with interindividual variability. 2 The most common initial symptoms are abdominal pain (lead colic) and other gastrointestinal symptoms (e.g., nausea, vomiting, constipation, diarrhea). Other affected systems include the central nervous (e.g., fatigue, malaise, impaired cognition, tinnitus, headaches, mood changes), peripheral nervous (e.g., peripheral neuropathy), hematologic (e.g., anemia with basophilic stippling), musculoskeletal (e.g., arthralgias, myalgias, saturnine gout), renal (e.g., impaired estimated glomerular filtration rate) and reproductive (e.g., decreased sperm count, decreased libido) systems. 2 Lead toxicity causes enzyme inhibition in the heme synthesis pathway, which can result in elevation of protoporphyrin levels. 11 Elevated lead levels are associated with adverse pregnancy outcomes including preterm birth, small-forgestational-age infants and pre-eclampsia. 12 Prenatal lead exposure is associated with impaired cognitive development in children. 13
Removing the exposure to lead is the most important part of management. Ongoing lead exposure is generally a contraindication to chelation. 12 The threshold for chelation of symptomatic patients is a blood lead level greater than 70–100 μg/dL, with lower thresholds for children and pregnant people. 12 The quality of the evidence for the effectiveness of chelation is not strong; thus, the decision should be made on an individualized basis in consultation with an expert. 2 With prolonged lead exposure, most lead is distributed to bone, with a smaller proportion to soft tissues, causing end-organ damage. The biological half-life of lead can be decades long in cortical bone. 12 Chelation reduces blood lead levels, but little evidence indicates that it can access lead in bone. A rebound of blood lead levels can occur after chelation but usually not to the pre-chelation level. 9