Asplenia and overwhelming postsplenectomy infection
Anatomic or functional asplenia removes the splenic clearance of opsonized encapsulated bacteria, creating a lifelong risk of overwhelming postsplenectomy infection (OPSI), a fulminant sepsis with 50% to 70% mortality. Any fever in an asplenic patient is an emergency treated with blood cultures and ceftriaxone plus vancomycin within 1 hour; prevention rests on pneumococcal, meningococcal ACWY and B, and Hib vaccination at least 14 days before elective splenectomy, plus penicillin prophylaxis in high-risk patients.
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What this article covers
- Overview
Definition: Asplenia is absence of the spleen, usually from splenectomy and rarely congenital; hyposplenism (functional asplenia) is a spleen present but nonfunctioning, most often from sickle cell disease autoinfarction.
- Epidemiology
Lifelong risk: Increased risk of severe infection persists for life and is highest in young children and early after splenectomy.
- Risk factors
Anatomic asplenia: Splenectomy for trauma, refractory immune thrombocytopenia, hereditary spherocytosis, or other hemolytic anemias, and congenital absence of the spleen.
- Pathophysiology
Loss of the bacterial filter: Encapsulated bacteria resist phagocytosis and are cleared only after opsonization by splenic macrophages, so absent splenic filtering lets them multiply unchecked in blood.
- Clinical features
Hallmark: Sudden-onset fever in a patient without a functioning spleen, progressing rapidly to septic shock.
- Differential diagnosis
Meningococcemia in a host with a spleen: Same petechial shock picture, but no asplenia history and Howell-Jolly bodies are absent; complement deficiency is the other host to suspect.
- Diagnosis
What establishes the diagnosis: OPSI is a clinical diagnosis of acute febrile illness in a patient with documented anatomic or functional asplenia; sepsis is confirmed by suspected infection plus an…
- Management
First, give empiric antibiotics within 1 hour of presentation, immediately after blood cultures: Ceftriaxone 2 g IV every 12 hours, continued until culture and susceptibility results return; for…
- Complications
Death: Mortality of OPSI reaches 50% to 70%, from refractory septic shock and multiorgan failure.
- Prognosis
OPSI mortality: Up to 50% to 70%, and septic mortality rises about 4% for every hour that care is delayed.
- Prevention
Vaccinate before elective splenectomy: Give pneumococcal, meningococcal, and Hib vaccines at least 14 days before surgery; after emergency splenectomy, vaccinate about 2 weeks after the operation.
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