What Is Metal Fume Fever?

Various heavy gold dust fume can generate gold dust fume. When the metal is heated just beyond its boiling point, it releases high-energy particles with a diameter of 0.2-lum, such as zinc oxide smoke, which penetrates deep into the respiratory tract. A large amount of contact with the alveoli can cause metal fume heat. Inhalation of large amounts of fine metal dust particles can also cause the disease. The metals that can cause metal fume are zinc, copper, and magnesium, especially zinc oxide. Chromium, antimony, arsenic, pot, drill, iron, lead, manganese, mercury, nickel, selenium, silver, hinge, sharp, tin, etc. can also be caused, but it is rare. Zinc has a low melting point and boiling point. When the metal is heated at high temperatures, a large amount of zinc vapor is first escaped and oxidized in the air to oxidize smoke and cause disease. When the ZnO concentration in the production ambient air is more than 15mg / m3, metal fume fever often occurs.

Jia Yawei

(Attending physician)

Department of Occupational Diseases, Shandong Occupational Diseases Hospital

Metal fume fever is an acute occupational disease and is caused by inhalation of a large number of newly formed gold filing oxide particles released during the heating process of gold filings. The clinical manifestations are flu, fever, chills, fever, and respiratory symptoms. Systemic diseases that are characterized by sudden onset of elevated body temperature and increased white blood cell count.

Western Medicine Name: Metal fume
English name: metal fume fever

Affiliated Department: Internal Medicine-
Main cause: Occupational disease
Contagious: Non-contagious

Causes of metal smoke fever

Metal fume occupational exposure

1. Metal heating workers: Metal smelting, casting, forging, gold spraying and other operations all require high temperatures. When casting copper, zinc is released first due to the low melting point and boiling point. The wells form zinc oxide smoke in the air, which is a common cause of metal smokers. Fine gold particles such as copper dust and manganese dust can also be used.

Cause disease.

2. Metal welding workers: The high temperature of gold chip welding and gas cutting can release zinc oxide smoke or oxidation pot smoke from galvanized or tinned metal. Welding or gas cutting alloys can also release metal fumes.

Metal smoke fever pathogenesis

Opinions are still inconsistent, and there are the following theories.

1. The direct toxic effect of gold shavings: Considering that the disease can be caused by the first exposure to ZnO smoke, the disease is not thought to be caused by the immune mechanism. Psoriasis damages the alveoli and releases denatured proteins that cause symptoms.

2. Pyrogen: Gold particles are engulfed by neutrophils in the body, releasing endogenous pyrogens, stimulating the body's temperature center and generating a thermal response.

3 Allergic reactions: Inhalation of metal oxide particles damages lung tissue, combines with metal-protein complexes to form antigens, and forms allergen-antibody complexes that can cause clinical symptoms.

4 Inflammatory response: After exposure to zinc fumes from welding, the number of neutrophils in bronchoalveolar lavage fluid increased with exposure dose. It is speculated that this increase in white blood cells may be related to the cytokines IL-8, IL-1 or TNF.

Clinical manifestations of metal fume fever

In the inhalation of metal wedding 4-8h (l-3h after the end of work), often onset at home in the evening after work, rarely onset at work. Being cold and tired is often the inducement. More cases in winter may be related to poor natural ventilation. At first feel metal or sweet taste in the mouth, dizziness, general weakness, loss of appetite, dry throat, sometimes dry cough, chest tightness, shortness of breath, dyspnea, headache, sometimes tolerance, vomiting, abdominal pain, muscle pain, joint pain, thirst, Shortness of breath, chills and chills later. The body temperature rose to 38-39 ° C or higher 10-12 hours after the metal smoke was inhaled. Usually lasts about 4-8h, sweating and fever. The next morning the symptoms almost completely disappeared and she was able to go to work.

Physical examination: Examination showed congestion of the eye conjunctiva and pharynx, increased breathing and heart rate, increased blood pressure, and a slight twist in the lungs.

Acute onset is self-limiting, and symptoms generally resolve within 24-48 hours or less with no sequelae. It can develop on first exposure to metal fumes. Patients can be tolerated without fever during continuous exposure to Jinjiu, but can recur when they resume exposure after 1-2 days of rest. This disease has been named "Monday Fever" and is believed to be related to rapid immunization.

Metal Fume Diagnosis and Differential Diagnosis

There is a clear history of new metal oxide smoke exposure, such as metal smelting, casting, gold spraying, welding and other operations. After a 4-8h incubation period, sudden fever and white blood cell count increase. The concentration of metal oxides, especially ZnO in the air of the workshop is of reference value. ZnOm3 rarely occurs, ZnO> 6mg / m3 can be affected, and ZnO> 15mg / m3 can often occur. Determination of blood zinc, urine zinc and other reference values. Comprehensive analysis can exclude other febrile diseases for diagnosis. The diagnostic standard is based on the occupational disease diagnostic standard "Metal Fume Diagnostic Standard".

Metal fume fever should be distinguished from diseases such as malaria, colds, acute cadmium poisoning, and allergic pneumonia.

1. Malaria: Plasmodium is detected in the blood;

2. Cold: Kata symptoms in the upper respiratory tract are obvious;

3 Acute cadmium poisoning: Inhalation of cadmium oxide smoke can cause acute lung damage. Early symptoms are similar to metal fume fever, but pneumonia or pulmonary edema can occur after 2-30h incubation period with severe breathing difficulties. Lung infiltration shadows. Increased urinary cadmium. After the welder's exposure to cadmium oxide smoke continued for 24 hours, he still had fever and severe chest pain, and cadmium poisoning should be suspected;

4. Allergic pneumonia has high fever, cough, dyspnea, and severe symptoms for a few hours after exposure to metal smoke. The first onset is late, often 3 years after starting work. The chest X-ray showed a slight reticular shadow on the lungs. Pulmonary function tests showed obstructive ventilation disorder. Lymphocytes in bronchoalveolar lavage fluid increased, mainly CD8, similar to allergic pneumonia.

Metal fume heat assisted inspection

1. Peripheral blood: white blood cells increased, mainly neutrophils increased, nuclear shifted to the left, the difference was significant before and after work.

2. Increased ESR: The patient's erythrocyte sedimentation rate increased rapidly for 12 hours after the patient's fever subsided.

3 Serum and urine levels of heavy gold are generally not related to the degree of symptoms, but can be used as a reference for exposure. If shortly after exposure to ZnO smoke, blood zinc often rises, exceeding the normal range of 11.5-18.4umol / L (0.75-1.2ug / L), and urine zinc can exceed 15.3umol / L (1mg / L). Urine copper can exceed 0.6umol / L (40ug / L) when casting copper.

4 Serum creatine kinase MM and MB increased. Individual patients with muscle and myocardial damage during multiple metal-fume episodes may have elevated serum creatine kinase.

5. Bronchoalveolar lavage fluid: the number of cells can increase significantly, mainly due to the increase in neutrophils.

Metal Fume Disease Treatment

Inhalation reactions generally do not require special medication. For the heavier, symptomatic treatment is given according to the condition.

1. If appropriate, give Chaihu Yinqiao detoxification tablets or ginger brown sugar tea to help reduce symptoms.

2. Those with high fever, especially those with abnormal or excessive fever, give 100 mg of hydrocortisone intravenously, or 10-20 mg of dexamethasone, and cooperate with physical cooling and fluid replacement (may add vitamin C 0.5 1.0g) and Treat symptomatically.

3. If the fever persists for more than one day, it should be investigated for secondary infection and metal poisoning, and treated according to the relevant cause.

Prognosis of Metal Fever Disease

The disease is a self-limiting benign disease, and there will be no sequelae after healing, and the original work can still be performed. After acute inhalation of zinc oxide smoke in animals, pathological changes only showed congestion in the tissues around the bronchus, exudate in the trachea, and a small amount of exudate and infiltration of white blood cells in the alveoli. No other organs were significantly changed. No sick dead have been seen in humans. Repeated smog fever can cause bronchial asthma. Long-term inhalation of metal can cause chronic metal poisoning.

Metal fume complications

Pharyngitis, upper respiratory tract infection, acute tracheitis, harmful gas inhalation toxic effects such as cadmium soot can cause cadmium poisoning.

Metal smoke fever disease prevention

Smelting and casting operations should use closed production as much as possible, and strengthen ventilation to prevent metal fume and harmful gases from being selected and recycled. When welding or cutting in a poorly ventilated place, ventilation should be strengthened. The operator should wear a ventilation mask or a dust mask, and shorten the working time.

Metal smoke fever care

1. Psychological care Because the patient did not understand the etiology, pathogenesis and prognosis of the disease after the onset of the disease, he was very worried. With the emergence of uncomfortable symptoms such as high fever, the patient's nervousness and fear were further strengthened Therefore, while providing patients with a quiet and comfortable treatment environment, they should take the initiative to introduce the patient's etiology, treatment, and related knowledge to the patient, and talk about the rapid recovery after active treatment without sequelae, eliminating their negative psychology and strengthening the patient. Confidence in defeating the disease and actively cooperate with treatment.

2. Nursing of high fever (1) Closely observe the change of body temperature: take a temperature measurement every 4h to observe the effect of antipyretics. (2) Skin care: Keep the skin clean and dry, and change the clothes soaked with sweat in time to prevent cold. (3) Keep your mouth clean. Rinse your mouth with tea and drink hot tea after meals to increase appetite and expel endogenous heat sources. (4) Give oxygen inhalation and take appropriate care.

3. Nursing to prevent complications, strengthen ECG monitoring, closely observe changes in heart rate and rhythm, observe changes in T waves, and understand the degree of myocardial ischemia and hypoxia. Observe changes in pulse, respiration, blood pressure and blood oxygen saturation, find abnormalities, report to the doctor in time and assist in taking preventive measures.

4. Do a good job of propaganda and education about occupational protection. Tell about the importance of implementing protective measures for metal fume heat. Instruct patients to wear protective masks and conduct ventilation in the laboratory when conducting tests on molten alloys. Attend regular medical examinations.

Metal fume expert opinion

Metal fume fever is a systemic disease that is caused by inhalation of new-born metal oxide smoke, which typically results in a sudden rise in body temperature and an increase in the number of blood white blood cells. In the case of mass disease, it is not easy to cause misdiagnosis because of the history of exposure to metal soot. When there are sporadic cases, the attending physician often ignores the history of occupational exposure, because its symptoms and signs are similar to diseases such as malaria, cold, and acute bronchitis Easy to cause misdiagnosis. It is also worth noting that some patients with metal fever first appeared, and then the metal poisoning occurred. Therefore, while diagnosing and managing metal fume fever, one should be alert to the possibility of metal poisoning throughout the body. Repeated smog fever can cause bronchial asthma. ^[1-2]