Bronchial Anthracofibrosis: A Perilous Consequence of Exposure to Biomass Fuel Smoke.

refers to the bluish-black discolouration of the bronchial mucosa due to inhalation of soot. The majority of those affected include coal workers, cigarette smokers and city dwellers. It is often an incidental finding seen on bronchoscopy and is due to the deposition of carbon as well as other mineral elements, such as iron, lead and cadmium. In 1951, Abraham Cohen2 described narrowing of the middle lobe in eight female patients due to perforated tuberculous lymph nodes. Of these eight patients, six had anthracotic pigmentation in the right middle lobe. This was the first ever description of what is now termed as “bronchial anthracofibrosis (BAF)”. This term was coined by Chung et al3 from Korea to highlight bronchoscopically visible anthracotic pigmentation associated with narrowing or obliteration of the bronchi. The authors observed this phenomenon in 28 elderly subjects of whom 20 were females having a significant wood smoke exposure, and characterised the disease entity. Among these, three-fourths had right middle lobe involvement with active tuberculosis seen in 61%. Endobronchial and lymph node tuberculosis were postulated as causative factors and it was recommended that active tuberculosis must always be ruled out in a patient with BAF. The authors even advocated the prompt institution of empirical anti-tuberculous treatment in all such patients, regardless of bacteriological confirmation. This notion has now been replaced and a mounting body of evidence has emerged to implicate biomass fuel smoke exposure as the major incriminating factor. It is estimated that nearly half the world’s population, especially in the developing countries, is dependent on biomass fuel for cooking, heating and lighting their homes.4 The common substances burnt are wood, charcoal, animal dung and crop wastes. Incomplete combustion of biomass fuel releases smoke containing nearly 200 compounds and gaseous pollutants along with solid particulate matter (PM 10 and PM 2.5).5 The problem is compounded by the fact that, in developing countries, cooking is often done in closed confines without a separate kitchen and with very poor ventilation. These houses often have a combined living and kitchen area and smoke is frequently seen lining the ceilings and walls in the form of blackish soot deposition. The two most important respirable particulate matter include PM 10 and PM 2.5. These particles are easily inhaled, bypass the pulmonary defense mechanisms and deposit deep within the lungs. The deleterious effects of biomass fuel smoke exposure includes neutrophilic inflammation, upregulation and deposition of fibronectin, lowered levels of pulmonary surfactant and oxidative stress leading to DNA (deoxyribonucleic acid) damage. In addition to this, exposure to biomass smoke leads to macrophagic dysfunction, reduced mucociliary mobility culminating in impaired immune response and significant decline in pulmonary functions.5 The National Family Health Survey-3 of India (2005–2006),6 reported that 89% of the rural households and 22% of the urban population used biomass fuel for cooking. The survey also revealed that 74% of the households cooked their meals within their homes and 32% lacked a separate kitchen. The National Sample Survey of India (2009-10),7 recorded that 76% of the population in the rural areas and 18% of the urban households were dependent on firewood for cooking. The World Health Organisation 2012 report8 estimated that, in 2010, 58% of the Indian population was still dependent on biomass fuel as a medium for cooking. The data from India presents an alarming picture with 500,000 deaths attributed to biomass fuel smoke exposure in 2000.9 The effect of biomass smoke on the respiratory system is different in adults and children. In children, it leads to a reduced lung growth and acute respiratory infections; while in adults, chronic obstructive pulmonary disease (COPD), asthma, interstitial lung diseases, respiratory tract infections, tuberculosis, lung cancer and cardiovascular diseases are the known hazards of biomass fuel smoke exposure.10 To this list of diseases due to biomass fuel smoke exposure, BAF has now been added and has emerged as a significant challenge.3,11 Bronchial anthracofibrosis was first recognised in India in a 65-year-old female with a history of woodsmoke exposure who presented with a middle lobe syndrome. Fibreoptic bronchoscopy not only revealed anthracotic pigmentation with narrowing of the middle lobe bronchus but Mycobacterium tuberculosis was also cultured from the bronchial aspirate.12 A review of the literature reveals that this condition is predominantly seen in elderly non-smoking females with long standing history of exposure to biomass fuel smoke. These patients are generally from rural background and have cooked for long in indoors on traditional chulhas in poorly ventilated areas.11 A study from Canada13 revealed that BAF associated with pulmonary tuberculosis was more likely to develop in immigrants from the Indian sub-continent (50%) as compared to those from other Asian countries (3.7%). The diagnostic clues that are seen on imaging can be pivotal for the diagnosis of BAF. The disease has a Bronchial Anthracofibrosis: A Perilous Consequence of Exposure to Biomass Fuel Smoke [Indian J Chest Dis Allied Sci 2015;57:151-153]