DESCRIPTION

Chromium is widely used in the metallurgical, refractory, and chemical industries as well as the tanning industry, pigment production, graphics, and many others.

FORMS AND USES

• Chromium compounds exist in a variety of valence states. Cr II (bivalent and basic), Cr III (trivalent and amphoteric), and Cr VI (hexavalent and acidic) are the commercially important forms.
• Compounds containing hexavalent chromium include chromic acid, potassium chromate, potassium dichromate, and sodium dichromate.

TOXIC DOSE

The lethal oral adult dose of has been estimated to be between 0.5 and 1.0 g of hexavalent chromium.

PATHOPHYSIOLOGY

• There is little conclusive evidence of toxic effects of divalent and trivalent chromium.
• The chromium in biological materials is usually trivalent.

EPIDEMIOLOGY

• Chromium may cause bronchogenic lung cancer in humans, the risk of which is increased by cigarette smoking.
• Chrome ulcers are common in tannery workers.
• Acute irritative dermatitis and allergic eczematous dermatitis are widespread in housewives, woodworkers, cement workers, limestone workers, radio factory workers, painters, and furniture polishers.
• Allergy to metals containing chromium, such as in acupuncture needles or military uniforms, is commonly reported.

CAUSES

• Most exposures are occupational.
• Child neglect or abuse should be considered if the patient is less than 1 year of age, suicide attempt if the patient is over 6 years of age.

WORKPLACE STANDARDS

For hexavalent chromium, expressed as chromium:

• ACGIH. TLV TWA (chromate) is 0.05 mg/m³.
• OSHA. PEL TWA is 0.1 ppm (0.25 mg/m³).
• NIOSH. IDLH is 15 mg/m³.

Section Outline:

• DESCRIPTION
• FORMS AND USES
• TOXIC DOSE
• PATHOPHYSIOLOGY
• EPIDEMIOLOGY
• CAUSES
• WORKPLACE STANDARDS

DIFFERENTIAL DIAGNOSIS

Other causes of caustic skin or gastrointestinal injury include acidic or basic corrosives.

SIGNS AND SYMPTOMS

Systemic effects resulting from acute ingestion include circulatory collapse, shock, and death.

Dermatologic

• Chrome ulcers are usually painless and occur most commonly on the fingers and hands.
• Acute irritative dermatitis and allergic eczematous dermatitis can occur and may be associated with yellow or orange skin discoloration.

Pulmonary

• High concentrations have been found in lung tissue after inhalation, which causes a pneumoconiosis that can be seen on chest radiograph.
• Both bronchial asthma and anaphylaxis have been reported after inhalation of chromium-containing dust.
• A corrosive reaction from chromium-containing mist commonly leads to ulceration and perforation of the nasal septum, particularly in welders.
• Systemic effects resulting from acute ingestion include pulmonary edema.

Gastrointestinal

Following ingestion, oral and gastrointestinal burns with hemorrhage are common.

Hepatic

Systemic effects resulting from acute ingestion include acute hepatitis.

Renal

Systemic effects resulting from acute ingestion include renal failure.

Hematologic

Systemic effects resulting from acute ingestion include thrombocytopenia and anemia.

Neurologic

Systemic effects resulting from acute ingestion include encephalopathy.

PROCEDURES AND LABORATORY TESTS

Essential Tests

No tests may be needed in asymptomatic patients.

Recommended Tests

• CBC, serum electrolytes, BUN, creatinine, liver function tests, and coagulation studies should be followed, as indicated by clinical condition.
• CT or MRI scanning from the nose to the abdomen must be considered in the first few days as a guide, due to the late development of abscess.

Not Recommended Tests

Blood or serum levels have not been found to be clinically useful.

Section Outline:

• DIFFERENTIAL DIAGNOSIS
• SIGNS AND SYMPTOMS
  • Dermatologic
  • Pulmonary
  • Gastrointestinal
  • Hepatic
  • Renal
  • Hematologic
  • Neurologic
• PROCEDURES AND LABORATORY TESTS
  • Essential Tests
  • Recommended Tests
  • Not Recommended Tests

Treatment should focus on general supportive care and decontamination.

DIRECTING PATIENT COURSE

The health-care professional should call the poison control center when:

• History of ingestion of hexavalent chromium is obtained.
• Toxic effects are not consistent with chromium poisoning.
• Coingestant or underlying disease presents an unusual problem.

Patients should be referred to a health-care facility when:

• History of ingestion of hexavalent chromium is obtained.
• Attempted suicide or homicide is possible.
• Coingestant or underlying disease presents an unusual problem.

Admission Considerations

Inpatient management in an intensive care setting is warranted for symptomatic patients after ingestion.

DECONTAMINATION

Ingestion

• Overall management is similar to acidic caustic agents
• Dilution with water or milk can be administered in the outpatient setting. Emesis should not be induced.
• Ascorbic acid, which reacts with hexavalent chromium to form the less toxic trivalent form, can be administered at 1 g per 0.135 g elemental chromium ingested.
• Activated charcoal is of questionable benefit.

Dermal

The skin should be washed copiously with tepid water and soaked in a 10% to 20% solution of ascorbic acid for 15 minutes.

ANTIDOTES

Dimercaprol (British anti-Lewisite), a heavy metal chelator, has been used successfully in some cases.

ADJUNCTIVE TREATMENT

• Ingestion. If significant gastrointestinal injury has occurred following ingestion, parenteral nutrition should be considered.
• Dermal. Wound care should include appropriate topical or systemic antibiotics, vitamin C, and tetanus prophylaxis.
• Inhalation
  • If dust inhalation is a possibility, the inside of the nose should be washed daily and the nasal septum covered with zinc or barium ointment.
  • Asthma attacks or anaphylaxis should be treated as usual.
• Hemodialysis has not been shown to have greater clearance rates than inherent renal clearance.

Section Outline:

• DIRECTING PATIENT COURSE
  • Admission Considerations
• DECONTAMINATION
  • Ingestion
  • Dermal
• ANTIDOTES
• ADJUNCTIVE TREATMENT

PATIENT MONITORING

Respiratory and cardiac monitoring should be performed continuously in symptomatic patients.

EXPECTED COURSE AND PROGNOSIS

• After acute ingestion, toxic effects usually peak within 24 hours, but caustic injury may require weeks to heal.
• Chronic inhalation may produce persistent pulmonary disease.

DISCHARGE CRITERIA/INSTRUCTIONS

• From the emergency department. Asymptomatic patients may be discharged after decontamination.
• From the hospital. Patient may be discharged when toxic effects resolve or stabilize.

Section Outline:

• PATIENT MONITORING
• EXPECTED COURSE AND PROGNOSIS
• DISCHARGE CRITERIA/INSTRUCTIONS

Grade II or III esophageal burns need follow-up gastrointestinal series to detect strictures.

Toxic effect of other metals: chromium.

See Also: SECTION III, British Anti-Lewisite (dimercaprol); SECTION IV, Caustics—Acidic.

RECOMMENDED READING

Deng JF, Fleeger AK, Sinks T. An outbreak of chromium ulcer in a manufacturing plant. Vet Human Tox 1990;32:142-146.

Authors: Scott D. Phillips and Melanie A. Wells

Reviewer: Richard C. Dart