Ans is A (Maximum risk is within 1 year of splenectomy) Overwhelming Postsplenectomy Infection (OPSI) Splenectomised patients are likely to suffer from severe infections. This syndrome is called overwhelming postsplenectomy infection (OPSI). OPSI is among the more devastating sequelae of asplenia and is the most common fatal late complication of splenectomy. The loss of the spleen's ability to filter and phagocytose bacteria and parasitized blood cells predisposes the patient to infection by encapsulated bacteria or parasites. Splenectomy also results in the loss of a significant source of antibody production. Infection may occur at any time after splenectomy; in one recent series, most infections occurred more than 2 years after splenectomy, and 42% occurred more than 5 years after splenectomy."- Sabiston I8/e The risk for OPSI is greater after splenectomy for malignancy or hematologic disease than for trauma. The risk also appears to be greater in young children (<4 years of age). OPSI may begin with a relatively mild-appearing prodrome, including fever, malaise, myalgias, headache, vomiting, diarrhea, and abdominal pain. These symptoms may then progress rapidly to fulminant bacteremic septic shock, with accompanying hypotension, anuria, disseminated intravascular coagulation, coma, and death within hours of presentation. The moality rate is between 50% and 70% for fully developed OPSI despite antibiotics and intensive care. Survivors often have a long and complicated hospital course with severe sequelae, such as peripheral gangrene requiring amputation, deafness from meningitis, mastoid osteomyelitis, bacterial endocarditis, and cardiac valvular destruction. S. pneumoniae is the most frequently involved organism in OPSI and is estimated to be responsible for between 50% and 90% of cases. Other organisms involved in OPSI include Haemophilus influenzae, Neisseria meningitidis, Streptococcus species and other pneumococcal species, Salmonella species, and Capnocytophaga canimorsus (implicated in OPSI as a sequela of dog bites). Currently, the standard of care for postsplenectomy patients includes immunization within 2 weeks of splenectomy with: - polyvalent pneumococcal vaccine (PPV23), - H. influenzae type b conjugate, and - meningococcal polysaccharide vaccine Antibiotic prophylaxis--usually a single daily dose of penicillin or amoxicillin--is recommended for asplenic children. (Antibiotic prophylaxis is controversia. Schwaz 9/e and Sabiston 18/e advise chemoprophylaxis; but Harrison 17/e does not recommend it)