SNAP, CRACKLE, AND POP: A CASE OF PEMETREXED-INDUCED INTERSTITIAL PNEUMONITIS

TOPIC: Diffuse Lung Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Pemetrexed is a folic acid inhibitor which used for the treatment of non-small cell lung cancer (NSCLC) (1). generally well tolerated, but interstitial pneumonitis an exceedingly rare, potentially fatal adverse effect (2). The diagnosis drug induced one exclusion and based on nonspecific clinical radiographic findings. Onset symptoms must correlate clinically with timing administration offending agent, improve removal medication initiation corticosteroids (3). It important clinicians to have high index suspicion initiate early treatment, reducing morbidity mortality. Below case patient adenocarcinoma who developed pemetrexed pneumonitis. CASE PRESENTATION: Our 85 year old man was diagnosed stage IVA adenocarcinoma. He received two cycles Carboplatin good radiologic response experienced intolerable side effects. decision made transition monotherapy. Two weeks after his second cycle, he dyspnea, low grade fevers fatigue, requiring supplemental oxygen (Vapotherm 60% FiO2 at 40 L/min) hospital admission. Physical exam notable diffuse crackles bilaterally. CTA Chest demonstrated bilateral ground glass opacities negative pulmonary embolism. empirically started broad spectrum antibiotics multifocal pneumonia. COVID-19, respiratory viral test, blood sputum cultures were all negative. Bronchoscopy bronchoalveolar lavage (BAL) normal airways. There no evidence alveolar hemorrhage. BAL count differential lymphocytic predominance. cytology macrophages mixed inflammatory cells atypical cells. High dose day five. Oxygen requirement steadily decreased, discharged few days later 2 L NC prolonged corticosteroid taper. DISCUSSION: widely first-line NSCLC. Pemetrexed-induced has range presentations, making it challenging diagnose. Presentations vary from asymptomatic life-threatening mechanical ventilation. Moreover, very rare Pemetrexed. This highlights importance having strong so that can be identified treated early, mitigating A thorough workup completed rule out other causes, especially infection. CONCLUSIONS: Through diagnosis, discontinued initiated sooner, risk improving outcomes should not rechallenged Pemetrexed, as this could fatal. REFERENCE #1: Dhakal, B., Singh, V., Shrestha, A., Rao, & Choong, N. (2011). Clinics Practice 1(4), 232-6. DOI: 10.4081/cp.2011.e106 #2: Kim, KH. et al. (2013). Interstitial cancer. Cancer Research Treatment 45(1), 74-7. 10.4143/crt.2013.45.1.74 #3: Skeoch, S. (2018). Drug-induced disease: systematic review. Journal Clinical Medicine 7(10), 1-30. 10.3390/jcm7100356 DISCLOSURES: No relevant relationships by Brent Bagley, source=Web Response Ethan Tope,