A 38-year-old female was referred to the outpatient clinic for recurrent severe abdominal pain. This was not associated with any vomiting or diarrhoea. She had been unwell for two years and had been seen in several gastroenterology clinics with unexplained abdominal pain and anaemia. She did not have any drug allergy. She was a married housewife with children. Clinical examination was unremarkable.
The patient had exhaustive gastrointestinal investigations including gastroscopy, colonoscopy, barium follow through and CT scan of the abdomen which were all normal. Urinary porphyrins were measured to investigate possible porphyria as the cause of abdominal pain. The urinary porphyrin results raised the possibility of lead poisoning and this was confirmed by two separate blood samples taken for serum lead level.
Her haemoglobin was 8.3 g/dl (12–16 g/dl), MCV 91 fl (82–100 fl). Her white cell count and platelet count were both normal. Thyroid function tests were normal as well. Serum iron was 14 μmol/l (6.6–30 μmol/l), TIBC 68 μmol/l (45–72 μmol/l), ferritin was 109 ng/l (4.6–204 ng/l). Haemoglobin electrophoresis showed normal haemoglobin electrophoretic pattern.
Her ESR was 28 mm/h and C-reactive protein was <7.0 mg/l (normal <10 mg/l). Liver function tests were normal. Gut hormone profile was within normal limits. Serum immunoglobulin levels were normal. 24 h urinary catecholamines were normal. Tumour markers including CEA, Ca 125 and Ca 19-9 were normal.
Blood porphyrins showed elevated erythrocyte zinc protoporphyrin at 1,731 nmol/l and erythrocyte free protoporphyrin at 748 nmol/l. Urinary porphyrin showed raised total coproporphyrin I and II level at 20,415 nmol/l (<115 nmol/l). Coproporphyrin-I level was 19,940 nmol/l. Erythrocyte 5-nucleotidase level was 5.6 IU/l (0–9 IU/l).
Her serum lead level was 779 μg/l (normal <100 μg/l) and on repeat testing was found to be raised at 707 μg/l. Serum folate and B12 levels were normal. Review of blood film confirmed basophilic stippling in red cells.
A blood sample was taken for the measurement of hepcidin prohormone by ELISA method (DRG Diagnostics, Immunodiagnostic Systems Ltd, Bolton Tyne and Wear, UK). The sample was stored at −80°C and allowed to return to room temperature before analysis and the result was 2,489 ng/ml. In healthy volunteers, prohepcidin levels have previously been reported to be less than 450 ng/ml [9
The source of lead poisoning was not identified. She had chelation therapy with penicillamine and her lead levels returned to normal.