Silicosis Misdiagnosed As Severe Asthma In A Gold Miner From Zamfara, North-Western Nigeria

Background: Silicosis is an incurable occupational fibrotic lung disease caused by inhalation of dust that contains crystalline silica. Illegal small-scale gold mining, one of the major occupations associated with the development of this disabling disease is carried out by artisans in Zamfara state, North-Western Nigeria. Miners uses local tools with little or no means of protection. Case summary: We present H.B, a 35-year-old gold miner who presented to our unit on account of recurrent cough and progressive shortness of breath of 1.5- and 1-year duration respectively. He received treatment for bronchial asthma from a private hospital for 2 months with no significant improvement. He has been mining gold at one of the gold mines in Maru, Zamfara state for 20 years but stopped a year ago on account of worsening breathlessness. On general physical examination, he was found to be in respiratory distress and centrally cyanosed with an SPO2 of 86% on room air. Examination of the chest revealed right apical flattening with tracheal deviation to the right and widespread wheezes and crackles all over the lung fields. Spirometric measurement revealed restrictive abnormality. Radiological examination by way of chest x-ray showed bilateral upper and mid zones homogenous opacities and 'tenting' of the left hemidiaphragm. Chest CT scan showed dense soft tissue masses in the upper lobes bilaterally with areas of calcifications including an 'egg shell' calcification on the right hilar region. A diagnosis of silicosis with progressive massive fibrosis was made. He was placed on nebulized levosalbutamol/ipratropium bromide and steroids and was optimized on oxygen therapy. He was subsequently counseled on the need to change occupation. Conclusion: Silicosis as one of the many causes of progressive fibrosis exists in our unregulated mining communities. The need for vigilance by clinicians and regulatory authorities is hereby emphasized.