An Unusual Pulmonary Complication Of Flecainide

SESSION TITLE: Medical Student/Resident Lung Pathology SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Flecainide is an anti-arrhythmic agent used mainly for supraventricular tachycardia (SVT). Pulmonary toxicity attributed to flecainide is an uncommon disorder with a wide spectrum of presentations, varying from acute pneumonitis to subacute and chronic presentations such as interstitial lung disease (ILD) or diffuse alveolar haemorrhage.(1-3) The low incidence of this toxicity can cause a delay in diagnosis and potentially irreversible complications. CASE PRESENTATION: An 80-year old male with a history of SVT on flecainide 50mg twice a day since 2016 was referred from a peripheral hospital with a 2-week history of dry cough, shortness of breath (SOB) and high grade fevers. He had been admitted there for 8 days and treated for a viral followed by bacterial pneumonia. His chest x-ray on presentation was unremarkable. Respiratory viral panel, work up for bacterial Pneumonia and QuantiFERON test were negative. He was empirically treated with a course of ceftriaxone and azithromycin. Despite treatment his symptoms progressively worsened. A Computed tomography scan of chest done on Day 3 and 6 (Figure 1,2) showed increasing bilateral peripheral infiltrates which mirrored the patient's clinical deterioration. Additional work up was significant for a sedimentation rate of 90mm/h and slightly positive Anti nuclear antibody(1:80).A transthoracic echocardiogram did not show evidence of infective endocarditis or elevated cardiac filling pressures. Due to worsening symptoms, patient underwent a diagnostic bronchoscopy which revealed a normal cell count with negative culture and cytology. Due to lack of response to antibiotics and negative bronchoscopy, there was concern for drug induced lung injury. His flecainide was discontinued and prednisone 50mg daily initiated for 4 weeks. The patient's symptoms immediately improved and he was discharged home with a diagnosis of flecainide induced organising pneumonia. At a 3 week follow-up, patients respiratory symptoms had resolved and chest x-ray showed resolution of pulmonary infiltrates. DISCUSSION: Organising pneumonia, a type of ILD can be subdivided into two groups based on aetiology. Cryptogenic Organising Pneumonia (COP) which is idiopathic and Secondary Organising Pneumonia which can be caused by medications, connective tissue disorders or malignancies. Lung biopsy is the gold standard for diagnosis and systemic high dose steroids are the mainstay of treatment. A high index of suspicion leading to early diagnosis can reduce morbidity and more importantly prevent fatal complications. CONCLUSIONS: Our patient had been on flecainide for years and presented with subacute symptoms of fever, dry cough and SOB. He was appropriately treated for infectious pneumonia but did not improve. Autoimmune disorders and malignancies were ruled out with work up. His symptoms only improved after discontinuation of flecainide and initiation of systemic steroids. Reference #1: Najjar N, Ong T, Ashby T, Seeram V. DIFFUSE ALVEOLAR HEMORRHAGE ASSOCIATED WITH FLECAINIDE. CHEST. 2019;156(4):A1252 Reference #2: Huang HD, Pietrasik GM, Serafini NJ, Sharma PS, Krishnan K, Trohman RG. Drug-induced acute pneumonitis following initiation of flecainide therapy after pulmonary vein isolation ablation in a patient with mitral stenosis and previous chronic amiodarone use. HeartRhythm Case Reports. 2019;5(1):53-55. Reference #3: Pesenti S, Lauque D, Daste G, Boulay V, Pujazon M-C, Carles P. Diffuse infiltrative lung disease associated with flecainide. Report of two cases. Respiration; international review of thoracic diseases. 2002;69:182-185. DISCLOSURES: No relevant relationships by Waqas Adeel, source=Web Response No relevant relationships by Sara Godil, source=Web Response No relevant relationships by Kareem Godil, source=Web Response No relevant relationships by Alaynna Kears, source=Web Response