What are the signs and symptoms of heavy metal toxicity?

Updated: Aug 24, 2018
  • Author: Adefris Adal, MD, MS; Chief Editor: Sage W Wiener, MD  more...
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Answer

The classic acute occupational heavy metal toxicity is metal fume fever (MFF), a self-limiting inhalation syndrome seen in workers exposed to metal oxide fumes. MFF, or "brass founder’s ague," "zinc shakes," or "Monday morning fever" as it is variously known, is characterized by fever, headache, fatigue, dyspnea, cough, and a metallic taste occurring within 3-10 hours after exposure. The usual culprit is zinc oxide, but MFF may occur with magnesium, cobalt, and copper oxide fumes as well.

Chronic occupational exposure to metal dusts has also been linked to the development of pneumoconioses, neuropathies, hepatorenal degeneration and a variety of cancers. These syndromes develop slowly over time and may be difficult to recognize clinically. In the United States, Occupational Safety and Health Administration (OSHA) regulations guide the surveillance of workers at risk and suggest exposure limits for metals of industrial importance.

This article provides a brief overview of general principles in the diagnosis and management of metal toxicity. The Table below reviews the typical presentation of the most commonly encountered metals and their treatment in summary form. It is not intended to guide clinical decision-making in specific cases. [5, 6, 7, 8, 9]

Table. Typical Presentation of the Most Commonly Encountered Metals and Their Treatment (Open Table in a new window)

Metal

Acute

Chronic

Toxic Concentration

Treatment

Arsenic

Nausea, vomiting,

"rice-water" diarrhea,

encephalopathy,

MODS, LoQTS,

painful neuropathy

Diabetes,

hypopigmentation/ hyperkeratosis,

cancer: lung, bladder, skin, encephalopathy

24-h urine:

≥50 µg/L urine, or

100 µg/g creatinine

BAL (acute, symptomatic)

Succimer

DMPS (Europe)

Bismuth

Renal failure; acute tubular necrosis

Diffuse myoclonic encephalopathy

No clear reference standard

*

Cadmium

Pneumonitis (oxide fumes)

Proteinuria, lung cancer, osteomalacia

Proteinuria and/or ≥15 µg/ g creatinine

*

Chromium

GI hemorrhage, hemolysis, acute renal failure (Cr6+ ingestion)

Pulmonary fibrosis, lung cancer (inhalation)

No clear reference standard

NAC (experimental)

Cobalt

Beer drinker’s (dilated) cardiomyopathy

Pneumoconiosis (inhaled); goiter

Normal excretion:

0.1-1.2 µg/L (serum)

0.1-2.2 µg/L (urine)

NAC

CaNa2 EDTA

Copper

Blue vomitus, GI irritation/ hemorrhage, hemolysis, MODS (ingested); MFF (inhaled)

vineyard sprayer’s lung (inhaled); Wilson disease (hepatic and basal ganglia degeneration)

Normal excretion:

25 µg/24 h (urine)

BAL

D-Penicillamine

Succimer

Iron

Vomiting, GI hemorrhage, cardiac depression, metabolic acidosis

Hepatic cirrhosis

Nontoxic: < 300 µg/dL

Severe: >500 µg/dL

Deferoxamine

Lead

Nausea, vomiting, encephalopathy (headache, seizures, ataxia, obtundation)

Encephalopathy, anemia, abdominal pain, nephropathy, foot-drop/ wrist-drop

Pediatric: symptoms or [Pb] ≥45 µ/dL (blood); Adult: symptoms or [Pb] ≥70 µ/dL

BAL

CaNa2 EDTA

Succimer

Manganese

MFF (inhaled)

Parkinson-like syndrome,

respiratory, neuropsychiatric

No clear reference standard

*

Mercury

Elemental (inhaled): fever, vomiting, diarrhea, ALI;

Inorganic salts (ingestion): caustic gastroenteritis

Nausea, metallic taste, gingivo-stomatitis, tremor, neurasthenia, nephrotic syndrome; hypersensitivity (Pink disease)

Background exposure "normal" limits:

10 µg/L (whole blood); 20 µg/L (24-h urine)

BAL

Succimer

DMPS (Europe)

Nickel

Dermatitis; nickel carbonyl: myocarditis, ALI, encephalopathy

Occupational (inhaled): pulmonary fibrosis, reduced sperm count, nasopharyngeal tumors

Excessive exposure:

≥8 µg/L (blood)

Severe poisoning:

≥500 µg/L (8-h urine)

*

Selenium

Caustic burns, pneumonitis, hypotension

Brittle hair and nails, red skin, paresthesia, hemiplegia

Mild toxicity: [Se] >1 mg/L (serum); Serious: >2 mg/L

*

Silver

Very high doses: hemorrhage, bone marrow suppression, pulmonary edema, hepatorenal necrosis

Argyria: blue-grey discoloration of skin, nails, mucosae

Asymptomatic workers have mean [Ag] of 11 µg/L (serum) and 2.6 µg/L (spot urine)

Selenium, vitamin E (experimental)

Thallium

Early: Vomiting, diarrhea, painful neuropathy, coma, autonomic instability, MODS

Late: Alopecia, Mees lines, residual neurologic symptoms

Alopecia, neuropathy

Toxic: >3 µg/L (blood)

MDAC

Prussian blue

Zinc

MFF (oxide fumes); vomiting, diarrhea, abdominal pain (ingestion)

Copper deficiency: anemia, neurologic degeneration, osteoporosis

Normal range:

0.6-1.1 mg/L (plasma)

10-14 mg/L (red cells)

*

*No accepted chelation regimen; contact a medical toxicologist regarding treatment plan.

MODS, multi-organ dysfunction syndrome; LoQTS, long QT syndrome; ALI, acute lung injury; ATN, acute tubular necrosis; ARF, acute renal failure; DMPS, 2,3-dimercapto-1-propane-sulfonic acid; CaNa2 EDTA, edetate calcium disodium; MDAC, multi-dose activated charcoal; NAC, N-acetylcysteine.


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