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DESCRIPTION
- Metal fume fever is an acute occupational self-limited illness that follows the inhalation of metal oxide fumes.
- The most common metals that cause metal fume fever are zinc, copper, brass (copper-zinc alloy), and magnesium.
- Less common are manganese, antimony, silver, tin, selenium, aluminum, nickel, chromium, vanadium, and stainless steel.
- Synonyms include brass chills, brazier's disease, galvanizer shakes, foundry ague or fever, metal malaria, Monday morning fever, solderer's fever, smelter shakes, welder's ague, welder's fever, zinc shakes, and "the smothers."
- Cadmium fume pneumonitis is discussed in SECTION IV, Cadmium Fume Fever.
PATHOPHYSIOLOGY
- When zinc or its alloys are heated above 930°F, particles of up to 1 micron in diameter are formed.
- Inhalation of particles less than 1 micron in diameter may result in metal fume fever, an acute febrile illness.
The exact etiology of metal fume fever is unknown; theories include:
- Modification of lung proteins because of absorption of metal oxide, reaction to foreign proteins, endotoxins, or a nonspecific response to interleukin-1
- Immune complex disease
- Interference of phagocytosis by metal particles accumulating in alveolar macrophages
- Hypersensitivity pneumonitis
- Delayed immunoglobulin E reaction
EPIDEMIOLOGY
- Toxic effects are common and underreported due to the benign nature.
- Death is not expected from this syndrome.
CAUSES
This is a disease of occupational exposure with high incidence in a select group of industries, most often the metal reclamation industry.
RISK FACTORS
- Employment as a welder is a risk factor.
- Metal fume fever also may occur among zinc smelters, brass solderers, brass foundry workers, chrome electroplaters, chrome welders, iron galvanizers, molten metal fabricators, metal grinders, manufacturers of steel alloys, workers near electric furnaces that are used to melt metals, and steel alloy manufacturers.
- Patients with previous pulmonary disease do not appear to be predisposed to metal fume fever and do not demonstrate unusual complications.
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DIFFERENTIAL DIAGNOSIS
- Further information on each poison is available in SECTION IV, CHEMICAL AND BIOLOGICAL AGENTS.
- Toxicologic causes of acute fever and respiratory complaints include salicylism, acute irritant gas inhalation (e.g., chlorine), chemical pneumonitis, polymer fume fever, occupational asthma due to metal oxides exposure, and nitrogen dioxide.
- Other causes include viral illness, malaria, pneumonia, sepsis, hypersensitivity pneumonitis, and pulmonary embolus.
- A careful occupational history is important to uncover exposure to metal oxide fumes. Chest discomfort and dyspnea with normal respiratory function and adequate oxygenation help to differentiate between infectious etiology and pulmonary embolism.
SIGNS AND SYMPTOMS
- Signs and symptoms develop rapidly and simultaneously within 4 to 12 hours of exposure to metal fumes. The symptoms disappear with only slight residual discomfort within 48 hours after removal from the source.
- Tachyphylaxis to the effect of metal fumes develops with repeated exposure; thus, symptoms improve during the work week. Symptoms resolve completely over the weekend, but recur with reexposure to the metal fumes (Monday morning fever).
- Generalized fatigue and chills are universal complaints.
Vital Signs
Fever and tachypnea are common.
HEENT
Sweet or metallic taste in the mouth, nasal irritation, sore throat, hoarseness, thirst, and headache may occur.
Dermatologic
Diaphoresis may occur, as may macular rash (rarely).
Pulmonary
- Chest tightness, wheezing, pleuritic chest pain, dyspnea, and nonproductive cough are common.
- Hemoptysis occurs rarely.
Gastrointestinal
Nausea, vomiting, and diffuse abdominal pain may occur.
Musculoskeletal
- Generalized arthralgia and myalgia occur.
- Fatigue and chills are common.
Neurologic
Weakness and lethargy may occur, as may paresthesia (rarely).
PROCEDURES AND LABORATORY TESTS
Essential Tests
There are no essential tests.
Recommended Tests
- Complete blood count may demonstrate leukocytosis.
- Arterial blood gases may show hypoxemia in severe cases.
- Spirometry may reveal lowered forced vital capacity (restrictive); it is rarely obstructive.
- Serum lactate dehydrogenase may be increased.
- Urinary or serum metals are often elevated but are of little help in the diagnosis.
- ECG, serum creatine kinase, and cardiac enzymes may be indicated based on signs and symptoms of chest pain and hypoxia.
- Chest radiograph is usually normal, but may show pneumonitis or pulmonary edema after severe exposure.
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- Exposure must be terminated and oxygen administered.
- Pulmonary supportive care is the basis of therapy.
- The exact composition of the metal and exposure time should be determined for all substances involved.
DIRECTING PATIENT COURSE
The health-care provider should call the poison control center when:
- cause of metal fume fever is unclear.
- drug interaction or underlying disease presents unusual problems.
DECONTAMINATION
The patient must be removed from exposure, undressed completely, and showered to remove any metal contaminants in the hair or on the skin.
ANTIDOTES
There is no specific antidote for metal fume fever.
ADJUNCTIVE TREATMENT
- Antipyretics are used to control fever; 1,000 mg of acetaminophen is administered every 4 to 6 hours, or 600 mg of ibuprofen is administered every 6 hours.
- The patient should be rehydrated either orally or intravenously.
- Analgesics are used to control pain.
- Bronchospasm
- Oxygen is administered, followed by albuterol 0.15 mg/kg (maximum 10 mg) in saline with humidified oxygen via nebulizer every 20 to 30 minutes. If the peak expiratory flow rate is greater than 90% after an initial dose, additional doses may not be needed. Response should be monitored.
- Methylprednisolone 60 to 125 mg (1.0-1.5 mg/kg) is administered intravenously every 6 to 8 hours. This may be decreased to a single daily dose and tapered rapidly.
- Initiation of prednisone should be considered, 2 mg/kg orally for several days.
- Not recommended therapies. Prophylactic antibiotics are not proven to be of value.
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EXPECTED COURSE AND PROGNOSIS
- Symptoms begin 4 to 12 hours after exposure; duration of illness is less than 48 hours; a temporary asymptomatic period may occur for 1 to 2 days afterward.
- Reexposure to metal oxide fumes will often cause recurrent metal fume fever, but is believed to be relatively benign, and long-term complications are not expected.
DISCHARGE CRITERIA/INSTRUCTIONS
The patient may be discharged when symptoms resolve and evaluation does not reveal a more serious process.
Section Outline:
ICD-9-CM 987Toxic effect of other gases, fumes, or vapors.
RECOMMENDED READING
Behrman A. In: Greenberg M, Phillps S, et al., eds. Occupational, industrial and environmental toxicology. St. Louis: Mosby, 1997:303-309.
Farrell FJ. Metal oxides. In: Sullivan JB Jr, Krieger GR, eds. Hazardous materials toxicology. Baltimore: Williams & Wilkins, 1992:921-927.
Offerman PV, Finley CJ. Metal fume fever. Ann Emerg Med 1992;21:872.
Author: Gerald F. O'Malley
Reviewer: Luke Yip