SESSION TYPE: Miscellaneous Global Case Report Posters
PRESENTED ON: Tuesday, October 23, 2012 at 01:30 PM - 02:30 PM
INTRODUCTION: We present a case of 33 year old male, working in an oil rig as a welder, who had acute onset breathlessness at work place. Without a detailed occupational history and knowledge of disease such patients would have been misdiagnosed.
CASE PRESENTATION: 33 year male , oil rig welder, presented on Monday evening to our emergency department with acute onset breathlessness after four hours of welding. He also complained of fever, throat pain, malaise, fatigue, odd taste in mouth, two episodes of vomiting, nausea, and severe cough. He is a non smoker and has no history of previous illness. On examination he could not complete a full sentence. His blood pressure was normal with pulse rate of 100 per minute, respiratory rate of 28 per minute and oxygen saturation was 90% on room air. Blood gas analysis showed partial pressure of oxygen of 60mmHg. Other clinical examination, and routine lab workup was unremarkable. Detailed occupational history revealed that he was working on galvanised steel and hence exposed to zinc oxide fumes. A diagnosis of metal fume fever was made and was managed conservatively with oxygen, inhaled bronchodilators, inhaled and oral steroids. He was well within 12 hours, was observed and discharged after two days.
DISCUSSION: Metal fume fever (MFF) is an occupational disease caused by inhalation of metal fumes. It is also called ‘galvaniser’s poisoning’, or ‘Monday morning fever’. This is because acute tolerance develops during daily exposure and the weekend away from work contributes to the syndrome’s reoccurrence when welding is recommenced on a Monday. Galvanized metal is steel that is coated with zinc oxide to protect the steel from oxidation, corrosion, and its eventual weakening. Workers engaged in heating or welding of galvanized materials are at risk of exposure to zinc oxide fumes. The high temperatures cause the metals to liberate fumes that include the oxides of the metal and other combustion products. Their inhalation can induce MFF. The Occupational Safety and Health Administration (OSHA) has set a legal limit of five milligrams of zinc oxide fume per cubic meter of air (5mg/m3) averaged over an 8-hour work shift. The National Institute for Occupational Safety and Health (NIOSH) recommends 5 mg/m3 averaged over a work shift up to 10-hours per day, 40-hours per week, with a short-term exposure limit of 10mg/m3 averaged over a 15- minute period (1). The pathophysiology is unclear. There is evidence of an exposure dependent neutrophil alveolitis in association with tumour necrosis factor a, interleukin 6, and interleukin 8 cytokine releases from pulmonary cells. The short-lived tolerance occurs because of induction of metallothionein protein synthesis. These proteins bind to heavy metals preventing toxic metal accumulation (2) Symptoms usually appear 3 to 10 hours after exposure and include fever, chills, headache, myalgia, fatigue, dyspnea, cough, excessive thirst, metallic taste, and excessive salivation. Neuthrophilic leukocytosis may be found on laboratory tests. The chest roentgenogram is usually normal. Recovery is spontaneous, within 24 to 48 hours. Treatment is mainly supportive, consisting of analgesics, antipyretics, and rest. There are no known late complications (3). Corticosteroids have not been shown to be of any benefit (1). The common differential is influenza, occupational asthma, acute lung injury or chemical pneumonitis. The self limiting course, normal radiological, pathological findings and occupational history differentiates it from other conditions.
CONCLUSIONS: MFF is an acute self limiting occupational syndrome. Its importance is that it often occurs in remote areas where emergency aid is negligible and yet it is easy to diagnose and manage. Increasing public and physician awareness, adequate protection, reduced time of exposure to metal fumes, will reduce the occurrence of this disease.
1) J La State Med Soc VOL 161 November/December 2009
2) Emerg Med J 2002;19: 268-269
3) Waldron HA. Non-neoplastic disorders due to metallic, chemical and physical agents. In: Raymond Parkes W. Occupational lung disorders. Oxford: Butterworth Heinemann, 1994:593-643
DISCLOSURE: The following authors have nothing to disclose: Sanjeev Mehta, Ruchira Shende, Bhavin Sampat
No Product/Research Disclosure InformationLilavati Hospital and Research Centre, Mumbai, India