HUT LUNG: A CASE OF MIXED DUST PNEUMOCONIOSIS

Abstract

SESSION TITLE: Medical Student/Resident Occupational and Environmental Lung Disease SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Pneumoconioses are a group of interstitial lung diseases (ILD) associated with occupational exposure. Domestically acquired mixed dust pneumoconiosis (MDP) from biomass combustion (Hut lung) is often reported in developing nations but rarely in the US. CASE PRESENTATION: A 76-year-old Hispanic female, non-smoker, who immigrated from Mexico 15 years ago, presented with 1 week of worsening dyspnea on exertion, subjective fever and cough productive of whitish sputum. Past history was significant for asthma and idiopathic ILD. Home medications included montelukast and inhaled albuterol and fluticasone. On admission, she was afebrile, hemodynamically stable and oxygen saturation (SpO2) was 65% on room air. CXR showed diffuse bilateral opacities. CT chest showed diffuse interstitial fibrotic changes, superimposed ground glass opacities and bronchiectasis. Supplemental oxygen, ceftriaxone and azithromycin were initiated, later switched to piperacillin-tazobactam and oral steroids. Blood/sputum cultures, respiratory viral panel, bacterial and fungal serology, HIV, autoimmune work-up, hypersensitivity pneumonitis panel were negative. On day 5, she was lethargic, SpO2 78% on high flow nasal cannula and was intubated. Video-assisted thoracoscopic biopsy showed fibrosis preliminarily reported as Usual Interstitial Pneumonia (UIP). She received 2 doses of azathioprine, 5 days of IVIG, 3 days of 1g solumedrol and trimethoprim/sulfamethoxazole for pneumocystis prophylaxis but had no response to treatment which is unusual for UIP. She developed shock. Norepinephrine drip was started. Confirmatory pathology from Cleveland Clinic showed chronic fibrosing interstitial process with honeycombing, interstitial and peri-bronchovascular mixed dust deposition consistent with MDP. Detailed environmental history revealed use of wood/coal-fueled stove in a small, ill-ventilated hut for several years in Mexico and no other occupational exposure. Ventilator requirements increased to 16 PEEP and 100% FiO2. Palliative care was consulted, and her family transitioned her to comfort care. DISCUSSION: Hut lung is a type of MDP characterized by carbon deposition, dust macules and fibrosis, reported primarily in women with chronic exposure to biomass smoke. Clinical presentation is nonspecific with symptoms of dyspnea, cough and respiratory distress. It is seldom considered in the differential diagnosis, as patients are usually women without typical occupational exposures. Duration of exposure correlates with severity of disease. The only effective form of treatment is prevention of further exposure, which makes early diagnosis a crucial step. Management involves avoidance of exposures and treatment of the underlying airway obstruction in line of COPD. CONCLUSIONS: There needs to be a high degree of suspicion for Hut lung (MDP) in women who have immigrated to the USA from countries where firewood is used for cooking. Reference #1: Assad NA, et al. Biomass smoke exposure and chronic lung disease. Curr Opin Pulm Med.2016;22(2):150–157 Reference #2: Raghu G, Collard HR, Egan JJ, et al. An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management. Am J Respir Crit Care Med 2011; 183:788–824. Reference #3: Sandoval J, Sales J, Martinez-Guerra ML, Et al. Pulmonary arterial hypertension and cor pulmonale associated with chronic domestic woodsmoke inhalation. Chest 103:12-20, 1993 DISCLOSURES: No relevant relationships by Eileen Hu-Wang, source=Web Response No relevant relationships by Manojna Nimmagadda, source=Web Response No relevant relationships by Roshan Thapa, source=Web Response No relevant relationships by Dhiran Verghese, source=Web Response