Antithrombotics/elasomeran/pembrolizumab

Abstract

Infusion site reaction in the form of skin necrosis: case reportA 76-year-old man developed infusion site reaction in the form of skin necrosis during treatment with heparin for atrial fibrillation and pulmonary embolism. Additionally, prophylactic therapy with enoxaparin sodium, pembrolizumab for poorly differentiated recurrent positive tonsillar squamous cell carcinoma and elasomeran for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) immunisation also contributed in the development of skin necrosis [not all dosages and routes stated].The man, who had stage IV poorly differentiated recurrent positive tonsillar squamous cell carcinoma, had been treated with six cycles of chemoimmunotherapy [details not stated] and radiotherapy. Thereafter, he received pembrolizumab maintenance therapy for 8 months. Subsequently, he developed dysphagia post percutaneous endoscopic gastrostomy tube placement. His medical history was also significant for chronic obstructive pulmonary disease and atrial fibrillation status post cardioversion. Therefore, he received continuous therapeutic IV infusion of heparin [unfractionated heparin] (14h administration). After 3 weeks of therapy, IV infusion of heparin therapy was stopped. Five weeks prior to the admission, he also received elasomeran [mRNA-1273] for SARS-CoV-2 immunisation. On current admission, he developed unresponsiveness and was intubated for acute hypoxic hypercapnic respiratory failure. On admission, the laboratory finding showed right upper lobe pulmonary embolism. Therefore, he started receiving treatment with continuous therapeutic IV infusion of heparin (70h administration). Prior to the administration of continuous infusion of heparin (14h administration), he also received prophylactic therapy with SC enoxaparin sodium [enoxaparin] 40mg every 24h (total five administrations) in the previous 6 months. Within 3 days of the initiation of IV infusion of heparin therapy, he developed multiple ecchymotic lesions on the right forearm near the heparin infusion site (infusion site reaction). His 4T score was found to be 6.The man's therapy with IV infusion of heparin was stopped. His platelet count dropped from 3 09 000/µL to 2 27 000/µL. While on heparin therapy, the INR, prothrombin time and partial thromboplastin time were found to be 1.5, 17 seconds and more than 200 seconds, respectively. Antiheparin platelet-factor-4 (PF4) IgG antibody ELISA was positive at an optical density (OD) of 1.00. Based on the clinical presentation and laboratory findings, skin necrosis secondary to the heparin, enoxaparin sodium, pembrolizumab and elasomeran was diagnosed. Thereafter, his heparin treatment was switched to bivalirudin. Five days after the discontinuation of heparin therapy, platelet serotonin release assay was found to be negative. The PF4 IgG antibody and PF4 highdose IgG assays were found to be 1.45OD and 2.15OD, respectively. During the hospital stay, he had significant haematuria and required continuous bladder irrigation. During this time, the platelet count in...