Clinical features:
(1) signs and symptoms of lead poisoning, which vary if the intoxication is acute or chronic:
(1a) acute intoxication may result in abdominal pain, hepatitis, acute renal injury, seizures, acute CNS symptoms and hypertension
(1b) chronic intoxication may result in nephropathy, neuropathy and chronic neurologic damage
(2) lead line on the gums
(3) in childhood exposures lead lines may be seen in X-rays of long bones due to lead deposition in the metaphysis
The patient develops a Coombs (direct antiglobulin) negative hemolytic anemia that may range from mild to severe.
Additional laboratory findings:
(1) red cells are normochromic or hypochromic (if there is reduced heme synthesis)
(2) reticulocytosis
(3) coarse basophilic stippling in peripheral red blood cells
(4) decreased serum haptoglobin
(5) elevated free erythrocyte protoporphyrin
(6) elevated urinary aminolevulinic acid (ALA) and elevated coproporphyrins
(7) elevated lead levels in serum or urine
where:
• Delta-aminodevulinic acid dehydrogenase is completely inhibited at a lead level of 70-90 µg/dL.
• Ferrochetolase in mitochondria is inhibited at lead levels over 15-30 µg/dL. Inhibition of this enzyme results in accumulation of erythrocyte protoporphyrins.
Differential diagnosis:
(1) other causes of hemolytic anemia
(2) other causes of anemia
