Lead poisoning by self-administration in an exposed worker

Lead poisoning is still a problem in the 21st century. Most cases involve children, but some result from environmental or occupational exposure. Chronic lead poisoning in the workplace is mainly due to inhalation of lead fumes or ingestion of lead compounds (during painting, lead smelting, pottery glazing, storage battery manufacture, etc.) [1, 2]. The case described here appears to be the first report of lead poisoning by a malingerer. A 51-year-old man admitted to hospital for lead poisoning had been exposed while working in a tin firm for 28 years. He complained of asthenia, weight loss (4 kg), headaches and constipation, but not abdominal colic. Physical examination was normal, particularly for deep tendon and plantar reflexes, and there was no sensory deficit. Biological studies found no anaemia or renal insufficiency. Blood lead concentration was initially 2.6 µmol l−1 (normal 0.25–1.25 µmol l−1), and urine lead concentration after an edetate calcium disodium (CaNa2EDTA) challenge test was 70 µmol 24 h−1. Erythrocyte protoporphyrin concentration was 2 µg g−1 Hb, and delta aminolevulinate concentration was elevated at 80 µmol l−1. Radiographs of the spine, humerus and femur were normal. The lead poisoning was initially considered to be of occupational origin. All family members had a normal blood lead concentration, and no other non-occupational sources of lead exposure were found. No abnormal lead concentration was detected in the water. The patient was treated three times with oral 2,3-dimercaptosuccinic acid (DMSA) and intravenous CaNa2EDTA, and twice with oral DMSA alone. However, the blood lead concentrations were maintained (4.5, 3.7, 4.5, 5.2, 2.8, 4.2 and 4.9 µmol l−1), indicating that poisoning was unlikely to be of occupational origin in a patient who had stopped working 6 months before. Abdominal radiography showed multiple radiopaque foreign bodies in the large intestine, ranging from 0.5 to 15 mm in size (Figure 1). X-ray analysis of some collected stools allowed the extraction of two radiopaque foreign bodies (Figure 1). Analysis of these extracted foreign bodies by electrothermal atomic absorption spectrometry found that they contained 301 mg of lead per gram. This indicated that the patient had induced poisoning by deliberate ingestion of lead compounds. Following psychiatric care and social management, his self-poisoning activity ceased. Abdominal radiography became normal, and blood lead concentrations returned to the reference range after further chelation treatments. Figure 1 Multiple radioopaque foreign bodies in the large intestine in abdominal radiography (Inset: X-ray of two radioopaque foreign bodies). Factitious disorders, characterized by the deliberate inducement of symptoms for no apparent purpose, are extremely rare causes of lead poisoning [3]. There are only five cases reported in the literature [4–8]. Our case differs from a factitious disorder, as the patient wished to be regarded as having an occupational illness. This case appears to be the first report of malingering [9] related to lead poisoning.