Letters to the Editor

CASE REPORT

Lead Poisoning Presents a Difficult Diagnosis



FREE PREVIEW Log in or buy this issue to read the full article. AAFP members and paid subscribers get free access to all articles. Subscribe now.


FREE PREVIEW Subscribe or buy this issue. AAFP members and paid subscribers get free access to all articles.

Am Fam Physician. 2002 Nov 15;66(10):1839-1841.

to the editor: Occult lead poisoning is a difficult diagnosis to make in a primary care setting because the symptoms of plumbism are non-specific. We would like to report a case in which unsuspected lead toxicity resulted in a delayed diagnosis and inconclusive hospital work-up.

A healthy 57-year-old man developed abdominal pain and lower back pain over the course of several days. He had no significant medical history, took no medications, and had no known allergies. He denied having any antecedent trauma and reported no other symptoms. His vital signs were normal and physical examination was unremarkable. Rapid office tests revealed a hemoglobin level of 9.7 g per dL (97 g per L) and blood on urine dipstick. The patient was admitted to the hospital for nephrolithiasis work-up and treatment. Despite an extensive three-day hospital evaluation, work-up was inconclusive.

At follow-up after discharge, the patient continued to have the same symptoms; he then revealed that he was a welder exposed to lead fumes. A whole blood lead level obtained at that time was greater than 100 mcg per dL (4.83 μmol per L), and he was re-admitted to the hospital for chelation therapy with dimer-caprol (or BAL) and edetate calcium sodium (CaNa2EDTA). Chelation was continued for five days. The patient's symptoms resolved, and the worksite evaluation was completed.

Symptoms of lead poisoning are often non-specific1 and include nausea, vomiting, abdominal pain, headache, back pain, paresthesias, limb weakness, and malaise. In severe cases, patients may present with encephalopathy. Without a history of exposure, lead poisoning has been mistaken for acute viral illness, sickle cell vasoocclusive crisis, gastro-enteritis, acute appendicitis, nephrolithiasis, and Guillain-Barré syndrome.1

Lead is primarily absorbed by the ingestion or inhalation of dust particles. Elevated lead levels greater than 10 mcg per dL (0.48 μmol per L) are associated with neurocognitive delays in children, and chronic lead intoxication in adults has resulted in hypertension, anemia, peripheral neuropathy, and nephropathy. Lead-induced nephropathy is one of the oldest described manifestations of plumbism, and it has been linked to adult-onset hypertension in several population surveys.2,3 Some centers have treated renal insufficiency and hypertension with routine chelation of body lead stores, although the long-term efficacy of such therapy still requires further evaluation.4

Since lead toxicity is so nonspecific, it should be considered in patients when diagnosis is unclear. Occupational exposure is the most common source for lead poisoning among adults. High-risk occupations include welding, batter manufacturing, mining, firing range maintenance, ship repair, glass blowing, and pottery glazing.1 The Occupational Safety and Health Administration requires removal from the worksite for a single surveillance level greater than 60 mcg per dL (2.90 μmol per L). Other common sources of lead poisoning in adults include lead-glazed dishes, food supplements contaminated with lead, herbal folk remedies, and moonshine whiskey.5,6 Unexplained anemia, basophilic stippling on the peripheral smear, and elevated creatinine are laboratory clues suggesting plumbism; the most important diagnostic maneuver is obtaining a whole blood lead level when plumbism is suspected. All patients recognized to have plumbism warrant immediate environmental intervention.

REFERENCES

1. Heneretig F. Lead. In: Goldfrank LR. Goldfrank's Toxicologic emergencies. 6th ed. Stamford, Conn: Appleton & Lange; 1998:1277–1309.

2. Loghman-Adham M. Renal effects of environmental and occupational lead exposure. Environ Health Perspect. 1997;105:928–39.

3. Cheng Y, Schwartz J, Sparrow D, Aro A, Weiss ST, Hu H. Bone lead and blood lead levels in relation to baseline blood pressure and the prospective development of hypertension: the Normative Aging Study. Am J Epidemiol. 2001;153:164–71.

4. Lin JL, Ho HH, Yu CC. Chelation therapy for patients with elevated body lead burden and progressive renal insufficiency. A randomized, controlled trial. Ann Intern Med. 1999;130:7–13.

5. Anderson NR, Gama R, Kapadia S. Herbal remedy poisoning presenting with acute abdomen and raised urine porphyrins. Ann Clin Biochem. 2001;38(Pt 4):408–10.

6. Morgan BW, Todd KH, Moore B. Elevated blood lead levels in urban moonshine drinkers. Ann Emerg Med. 2001;37:51–4.

Send letters to Kenneth W. Lin, MD, MPH, Associate Deputy Editor for AFP Online, e-mail: afplet@aafp.org, or 11400 Tomahawk Creek Pkwy., Leawood, KS 66211-2680.

Please include your complete address, e-mail address, and telephone number. Letters should be fewer than 400 words and limited to six references, one table or figure, and three authors.

Letters submitted for publication in AFP must not be submitted to any other publication. Possible conflicts of interest must be disclosed at time of submission. Submission of a letter will be construed as granting the American Academy of Family Physicians permission to publish the letter in any of its publications in any form. The editors may edit letters to meet style and space requirements.


Copyright © 2002 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact afpserv@aafp.org for copyright questions and/or permission requests.

Want to use this article elsewhere? Get Permissions


Article Tools

  • Print page
  • Share this page
  • AFP CME Quiz

Information From Industry

Navigate this Article