Which patient population is at the highest risk for overwhelming post-splenectomy infection (OPSI)?

Overwhelming post-splenectomy infection (OPSI) is a significant concern following splenectomy, particularly because the spleen plays a critical role in the immune response to certain bacterial infections, especially those caused by encapsulated organisms such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae.

The pediatric population, particularly children under 4 years of age, faces a heightened risk for OPSI after splenectomy due to their still-developing immune systems. In children, splenic function is crucial for mounting effective responses to encapsulated bacteria. Therefore, young children who undergo procedures that cause the loss of splenic function, like splenectomy, remain particularly vulnerable to severe infections.

While patients with immune disorders, such as those with immune thrombocytopenic purpura (ITP) or myelofibrosis, and adults with chronic conditions like diabetes do face risks associated with splenectomy, the relative risk is significantly escalated in very young children because their immune defenses are not fully matured. This age group has been well-documented in medical literature as being at the highest risk for severe or overwhelming infections post-splenectomy, necessitating careful monitoring and preventive measures such as vaccinations