Metal fume fever is an acute occupational disease caused by inhalation of metal vapors formed when various metals and alloys are heated to a state of melting or boiling. The disease is manifested by a sharp increase in body temperature and is accompanied by chills, headache, disruption of the respiratory system, digestive tract. When making a diagnosis, the relationship of clinical manifestations with the performance of appropriate work, laboratory analysis data, X-ray examination of the chest organs are taken into account. Conservative symptomatic treatment is prescribed.
ICD 10
T56.5
Meaning
Metal fume (copper foundry, brass, metal, zinc) fever is an occupational disease of workers in the metallurgical industry, shipbuilding. It is found among workers serving melting furnaces engaged in scrap disposal, grinding, galvanization, electric welding and gas cutting of metal products. Due to the physico-chemical properties of zinc, workers working with galvanized steel, manufacturers of zinc whitewash, foundries of alloys that include this metal are more susceptible to the disease. Several cases of severe metal fume fever caused by exposure to gases – zinc derivatives – during military exercises have been described. Recently, metal fume fever is rare and develops in violation of safety regulations.
Causes of metal fume fever
The immediate cause of the disease is the ingress into the respiratory tract of a highly dispersed aerosol formed by the interaction of metal vapors with oxygen in the air. Such an aerosol is saturated with metal particles of 0.4–0.6 microns in size. More often, metal fume fever develops when zinc vapor is inhaled. This metal is capable of melting and boiling at relatively low temperatures (416 and 906 degrees, respectively). For casting, zinc-containing alloys are heated to 1000 °With and more. Zinc intensively turns into a gaseous state and pollutes the inhaled air. Pairs of copper, silver, iron, selenium, cadmium and some other metals are also capable of provoking the development of a pathological process.
Pathogenesis
The mechanism of development of metal fume fever is not fully understood. It is assumed that metal microparticles, due to their small size, have the ability to penetrate the lower respiratory tract and reach the pulmonary alveoli. Once in the cells, they cause protein denaturation and trigger a cascade of reactions that release pyrogens. There is a feverish state of aseptic protein nature. Specialists in the field of pulmonology do not exclude immune mechanisms of the disease, relying on the development of tolerance in workers with long experience. However, the corresponding antibodies were never detected.
Symptoms of metal fume fever
The first signs of the disease usually appear 3-6 hours after the harmful effects. The febrile syndrome is preceded by a prodromal period. Initially, there is a sweet taste and a feeling of dryness in the mouth. Then the symptoms of general malaise are added. The victim is concerned about headache, feeling of weakness, pronounced general weakness, drowsiness, myalgia. On the part of the respiratory organs, the phenomena of pharyngitis and laryngotracheitis prevail. There is a tickling and sore throat, hoarseness of voice. Digestive disorders are manifested by a decrease in appetite, heaviness in the right hypochondrium.
Soon there is actually a feverish state. Body temperature rises to high febrile and hyperthermic values, accompanied by severe chills. The headache becomes even more pronounced. It is often accompanied by confusion of consciousness, delirium. Chest pains are added, which increase with deep breathing, heaviness in the chest, dry paroxysmal cough. Sometimes bronchospasm occurs. The patient experiences nausea, vomiting and diarrhea appear. After 6-8 hours, the attack ends with heavy sweating. The temperature drops sharply to normal numbers. Signs of general malaise persist for 2-3 days.
Complications
Usually metal fume fever proceeds favorably and without consequences. The ability to work is fully restored in 3-7 days. The victim acquires short-term immunity. Sometimes multiple repeated episodes of the disease provoke the occurrence of chronic bronchitis. Inhalation of zinc chloride gas, used in military operations and during exercises, leads to the development of severe zinc fever. It is complicated by respiratory distress syndrome and often ends with the death of the victim.
Diagnostics
If there is a suspicion of an occupational disease, a professional pathologist is engaged in examining patients. The diagnostic search begins with a survey, clarification of the professional route. It is necessary to establish a time interval from the moment of harmful effects to the onset of a feverish state. This will help to differentiate metal fume fever from influenza, acute bacterial infection, malaria. The final diagnosis is made on the basis of:
- Inspection. There is redness of the skin of the face, hyperemia of the throat. There may be urticary rashes on the body. The patient’s sclera are injected, there are signs of conjunctivitis. Often there are signs of neurological disorders – tremor, wide pupils, increased reflexes.
- Physical examination. Metal fume fever is characterized by variability of physical data. Palpation determines the enlargement of the liver. In the lungs, dry and (or) wet multi-calibre wheezes are heard, sometimes – the noise of pleural friction. With auscultation of the heart, tachycardia, cardiac arrhythmias are detected.
- Laboratory tests. In the study of peripheral blood, neutrophilic leukocytosis is noted with a shift of the leukocyte formula towards rod cells, later lymphocytosis appears. The level of glucose, lactate dehydrogenase increases. To exclude malaria, a blood test for malarial plasmodium is performed. In the analysis of urine, proteinuria, leukocyturia, hematoporphyrin, urobilin are determined.
- Chest x-ray. When performing a radiation examination in the first hours of the disease, acute pulmonary emphysema is observed. Later, indistinct blurred small-focal bilateral shadows appear. If metal fume fever is complicated by pneumonia, larger areas of infiltration of lung tissue from one or both sides are detected.
- Functional diagnostic methods. With metal fume fever, spirometry indicators may remain normal. However, mixed violations of the function of external respiration are more often determined. There is a decrease in the forced vital capacity of the lungs and the volume of forced exhalation in 1 second. These changes are transient. The indicators quickly recover to normal values after recovery.
Metal fume fever treatment
Therapy of a febrile condition caused by inhalation of metal vapors is carried out by the syndrome. As a first aid, plentiful sweet drinks, warm baths and bed rest are recommended. Large doses of ascorbic acid are indicated orally or intravenously on a glucose solution. Antihistamines of the first generation, nonsteroidal anti-inflammatory drugs are used. With the phenomena of laryngitis, tracheitis, bronchitis, alkaline inhalations are prescribed. With severe respiratory failure, oxygen therapy, corticosteroid hormones are used. The development of pneumonia is an indication for the use of antibacterial agents.
Prognosis and prevention
In most cases, the prognosis is favorable. Metal fume fever ends with complete recovery, the chronization of the process does not occur. Isolated cases of severe course of the disease with the development of acute respiratory failure and fatal outcome are described. To prevent illness, workplaces should be equipped with supply and exhaust ventilation. The risk of developing occupational pathology is reduced by the availability of modern equipment (electric melting furnaces), mechanization of molten metal filling processes. For personal prevention, it is necessary to use personal protective equipment, take a warm shower after work is completed.
Literature
- Comparative hazard identification by a single dose lung exposure of zinc oxide and silver nanomaterials in mice. Gosens I, Kermanizadeh A, Jacobsen NR, Lenz AG, Bokkers B, de Jong WH, Krystek P, Tran L, Stone V, Wallin H, Stoeger T, Cassee FR. PLoS One. 2015 May 12;10(5):e0126934. link
- Acute inhalation injury. Gorguner M, Akgun M. Eurasian J Med. 2010 Apr;42(1):28-35. link
- Respiratory health of a population of welders. Al-Otaibi ST. J Family Community Med. 2014 Sep;21(3):162-5. link
- Characterization of indoor dust from Brazil and evaluation of the cytotoxicity in A549 lung cells. Deschamps E, Weidler PG, Friedrich F, Weiss C, Diabaté S. Environ Geochem Health. 2014 Apr;36(2):225-33. link