What is a key characteristic of overwhelming postsplenectomy sepsis (OPSI)?

Overwhelming Postsplenectomy Sepsis: Key Characteristics

Overwhelming postsplenectomy sepsis (OPSI) can be fatal within hours of onset, with most deaths occurring within the first 24 hours after symptoms begin. 1

Pathophysiology and Risk Factors

OPSI is defined as fulminant sepsis, meningitis, or pneumonia primarily triggered by encapsulated bacteria:

• Streptococcus pneumoniae (50% of cases)
• Haemophilus influenzae type B
• Neisseria meningitidis 1

Risk Timeline

• The risk of OPSI and associated death is highest in the first 1-2 years after splenectomy 1
• However, the risk remains elevated for more than 10 years and is likely lifelong 1
• Cases of fulminating infection have been reported more than 20 years after splenectomy 1, 2
• The longest documented interval between splenectomy and subsequent sepsis was 42 years 2

Age-Related Risk

• Children under 5 years have significantly higher infection rates (>10%) compared to adults (<1%) 1, 3
• The risk exceeds 30% in neonates 1
• OPSI is not most common in elderly patients, but rather in young children 1

Presence of Accessory Spleens

• The presence of accessory spleens does not prevent OPSI
• Cases of fatal OPSI have been documented despite remaining splenic tissue or splenosis 2

Clinical Presentation and Progression

OPSI is characterized by:

• Sudden onset of fever, malaise, and chills
• Rapid progression to fulminant sepsis
• Potential development within hours of symptom onset 1, 4

Mortality

• The mortality rate ranges from 30% to 70% 1
• Most deaths occur within the first 24 hours after onset 1
• The rapid progression makes prompt diagnosis and immediate treatment essential for survival 1

Prevention Strategies

Vaccination

• Patients should receive immunization against encapsulated bacteria (S. pneumoniae, H. influenzae, N. meningitidis) 1, 3
• Vaccination should ideally be given at least 2 weeks before elective splenectomy 1, 3
• For emergency splenectomy, vaccination should start no sooner than 14 days after the procedure 1
• Annual influenza vaccination is recommended for all patients over 6 months of age 1, 3

Antibiotic Prophylaxis

• At least 2 years of prophylactic antibiotics are recommended after splenectomy 1, 3
• Lifelong prophylaxis should be considered, especially for high-risk patients 1, 3
• Patients should keep emergency antibiotics at home for immediate use if infection symptoms develop 3

Patient Education

• Patients must understand the lifelong risk of severe infection
• They should seek immediate medical attention for fever >38°C (101°F) 3
• Medical alert bracelets/cards indicating asplenic status are recommended 3

Common Pitfalls in OPSI Management

1. Delayed recognition of symptoms: The rapid progression from initial symptoms to death means any delay in treatment can be fatal.

2. Inadequate vaccination: Failure to provide comprehensive vaccination against encapsulated bacteria significantly increases risk.

3. Discontinuing antibiotic prophylaxis too early: The risk of OPSI persists for life, not just the immediate post-operative period.

4. Assuming accessory spleens provide protection: OPSI can occur despite the presence of accessory splenic tissue 2.

5. Focusing only on elderly patients: Children under 5 years have the highest risk, not elderly patients 1.

In conclusion, OPSI represents a medical emergency with rapid progression and high mortality. The key characteristic among the options presented is that OPSI can be fatal within hours of onset, making immediate recognition and treatment essential for survival.