Prosthetic double valve endocarditis caused by Streptococcus pneumoniae due to overwhelming post-splenectomy infection (OPSI) in a pre-vaccine licensure era: A case report.

Overwhelming post-splenectomy infection (OPSI) is a severe and potentially life-threatening condition that can occur in patients undergoing splenectomy. We report a case of a patient who had a splenectomy approximately 30 years ago during prosthetic valve insertion for infective endocarditis (IE). The patient later developed prosthetic valve endocarditis caused by Streptococcus pneumoniae associated with OPSI. Although IE due to Streptococcus pneumoniae is rare, the presence of a prosthetic valve may increase the risk of IE in splenectomized patients. This case highlights the need for increased vigilance in managing these patients. Additionally, this case represents a missed opportunity for vaccination, as the splenectomy was performed before the approval of the 23-valent pneumococcal polysaccharide vaccine in Japan. This underscores the importance of establishing a system to ensure appropriate vaccine catch-up and to provide educational opportunities for patients who have undergone splenectomy.