INTRODUCTION:Lung injury secondary to rural indoor air pollution from particulate matter termed “hut lung” covers respiratory conditions from acute lower respiratory infection to interstitial lung diseases to COPD. Containing various polluting compounds, biofuels are used by almost 3 billion people over the world. Global mortality from indoor air pollution in 2000 is estimated between 1.5 to 2 million deaths.
CASE PRESENTATION:The patient is an 87 year old Spanish speaking female who presents after a fall. She presented with complaints of right rib and wrist pain. The patient’s daughter states she had flown from Mexico one week ago with “flu-like” symptoms and had outpatient treatment with azithromycin. Her symptoms included non productive cough, subjective fever and anorexia. She denied any other complaints.She has no past medical history or allergies. She had prior hernia repairs. She was taking OTC cough medicine and eye drops for conjunctivitis. She denied tobacco or alcohol usage. Her family history was noncontributory. Physical exam findings included vitals signs in the normal range. The lungs revealed bilateral coarse breath sounds with rhonchi. The rest of the exam was benign. Her white cell count was elevated. Her chest x-ray showed a right lower lobe infiltrate. Chest CT scan showed bilateral dense alveolar infiltrates in the left upper lobe and right upper and lower lobe and a 1.8 cm nodule in her right lower lobe. She underwent a closed reduction of the fracture. She developed oxygen de-saturation and hypercarbia requiring mechanical ventilation and started on broad spectrum antibiotic coverage.Under bronchoscopy, diffuse blackish-grey mucosal lesions were seen throughout her airways bilaterally with widespread edema and narrowed airways. Her BAL cultures were negative. The cytology showed carbon laden macrophages. On further questioning after extubation, she stated that she was worked over a charcoal stove for many years.
DISCUSSIONS:Biofuels are the major source of domestic energy in under developed countries predominantly in rural areas. An inefficient fuel source, biofuel, require that fires be kept burning for many hours in poorly ventilated houses. The poverty level correlates with biofuel usage. Appropriately half of the total exposure occurs in a short amount of time when the stove emissions are the highest and the person is closest to the stove while cooking. Particulate matter measurements were 2 to 200 times higher than the U.S. EPA regulations for outdoor air pollutants. Indoor air pollution, a growing health concern, was investigated in many countries in the 1970’s. In Iran, non smoking women exposed to indoor pollution were found to have respiratory symptoms in middle life leading to disability. Histologic investigation showed anthracosis and free black particles. “Hut lung” can present with a variety of signs and symptoms such as cough, dyspnea, cynosis, crackles on auscultation, hepatomegaly, pulmonary hypertension, edema, and cor pulmonare. The radiological findings are diffuse pulmonary nodules, reticulation, peribronchovascular thickening, and nodular and ground glass opacities. Histological findings are carbon pigment deposition around the terminal bronchioles, dust laden macrophages and mixed dust fibrosis.
CONCLUSION:In dealing with patients from foreign rural settings with non specific respiratory symptoms or complaints, the possibility of injury from indoor air pollution should be considered. This requires detailed personal and work history. While imaging may be nonspecific, histology from either transbronchial or open lung biopsy seems to be the gold standard.
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