Where Ingested Lead Initially Makes Contact in the Body
Ingested lead first makes contact with the gastrointestinal tract, beginning in the stomach and then moving through the small intestine where absorption primarily occurs. 1, 2
Initial Contact and Absorption Sites
Gastrointestinal Tract Entry
- Lead enters through the mouth and travels to the stomach as the first major site of contact 1, 3
- The stomach contains the ingested lead material initially, as documented by abdominal radiographs showing lead objects in the gastric region 1
- From the stomach, lead moves into the small intestine (jejunum) where it continues transit through the GI tract 3
Absorption Characteristics
- Pediatric patients absorb lead from the GI tract more quickly than adults, making children particularly vulnerable to rapid blood lead level elevations 2
- Acute elevations of blood lead concentrations can occur within hours of ingestion—blood lead levels can rise from baseline to 57 μg/dL within 13 hours and peak at 79 μg/dL by 36 hours after ingestion of lead shot 1
- The speed of absorption depends on the acid solubility of the lead compound and gastrointestinal transit time 4
Clinical Implications of GI Contact
Risk Factors for Increased Absorption
- Prolonged GI transit time increases lead absorption from ingested foreign bodies 4, 1
- Presence of gastrointestinal pathology enhances absorption risk 4
- Small diameter lead objects (like lead shot or pellets) have greater surface area exposure to gastric acid, facilitating more rapid absorption 1, 2
Common Pitfall
A critical error is assuming that elemental lead foreign bodies pose low absorption risk—multiple small lead objects can cause rapid, clinically significant blood lead elevations requiring urgent intervention, even in previously healthy children 1, 2
Systemic Distribution After GI Absorption
- Once absorbed from the GI tract, lead enters the bloodstream (measured as blood lead level) 5, 6
- Lead then distributes to bone, brain, kidney, and other tissues where it exerts toxic effects 7, 4
- Lead can be mobilized from maternal bone during pregnancy and lactation, representing an internal source of exposure 7