How should I manage overwhelming post‑splenectomy infection (OPSI), including emergency antibiotic therapy, supportive care, vaccination schedule, and lifelong antibiotic prophylaxis?

Management of Overwhelming Post-Splenectomy Infection (OPSI)

Emergency Antibiotic Therapy for Suspected OPSI

When OPSI is suspected, immediately administer intravenous benzylpenicillin 1200 mg (2 million units) over 3-4 minutes to adults and children over 10 years of age, without waiting for laboratory confirmation. 1

• Obtain blood cultures and relevant specimens before antibiotic administration, but never delay treatment for diagnostic workup 1
• If benzylpenicillin is unavailable, use third-generation cephalosporins (ceftriaxone or cefotaxime) as the empiric regimen 2, 3
• For critically ill patients presenting with septic shock, combine vancomycin with ceftriaxone to cover resistant pneumococcal strains 2
• Modify the antimicrobial regimen once culture and susceptibility results become available 1
• Clinical deterioration can occur within 4-24 hours despite appropriate antibiotics, with mortality rates of 30-70% if treatment is delayed 4, 2

Supportive Care and Aggressive Resuscitation

Initiate early goal-directed therapy immediately upon recognition of septic shock, as aggressive resuscitation can reduce mortality from 70% to 10-40%. 2

• Prevent progression to low-cardiac-output stage and disseminated intravascular coagulation (DIC) through aggressive fluid resuscitation and vasopressor support 5
• Close hemodynamic monitoring is mandatory, as the low-output stage with DIC is often irreversible once established 5
• Most deaths occur within 24 hours of symptom onset, making rapid escalation of care critical 1

Vaccination Schedule

Administer all vaccines at least 14 days (minimum 2 weeks) before elective splenectomy; ideally 4-6 weeks pre-operatively for optimal antibody response. 1, 6, 7

Pre-operative vaccination (elective splenectomy):

• PCV20 (preferred) or PCV15 as the initial pneumococcal vaccine 6, 7
• If PCV15 is given, follow with PPSV23 at least 8 weeks later 6
• Both MenACWY and MenB vaccines (MenACWY as 2 doses 8 weeks apart; MenB as 2- or 3-dose series depending on formulation) 6, 7
• Single dose of Haemophilus influenzae type b (Hib) vaccine for unvaccinated adults 6, 7
• Annual inactivated or recombinant influenza vaccine 6, 7

Post-operative vaccination (emergency splenectomy):

• Wait at least 14 days post-operatively before vaccinating, as antibody response is suboptimal earlier 6, 7
• If the patient is at high risk of missing vaccination, administer before discharge despite suboptimal timing 7

Revaccination schedule:

• PPSV23 every 5 years for life 6, 7
• MenACWY every 5 years for life 6, 7
• MenB every 2-3 years if risk remains 6, 7
• Annual influenza vaccine 6, 7

Special consideration for rituximab:

• Patients who received rituximab in the previous 6 months may have suboptimal vaccine response; reassess vaccination once B-cell recovery has occurred 8, 6

Lifelong Antibiotic Prophylaxis

All asplenic patients require lifelong prophylactic antibiotics, with mandatory coverage for at least the first 2 years post-splenectomy when OPSI risk is highest. 1, 7

Standard prophylactic regimen:

• Phenoxymethylpenicillin (penicillin VK) 250-500 mg orally twice daily for adults 8, 1, 7
• Children <5 years: 125 mg twice daily 1
• Children 5-14 years: 250 mg twice daily 1
• Erythromycin 250-500 mg orally twice daily for penicillin-allergic patients 8, 1, 7

Critical limitation:

• Phenoxymethylpenicillin does not reliably cover Haemophilus influenzae, making Hib vaccination essential 1, 7
• Documented failures of prophylaxis have been reported, emphasizing that antibiotics reduce but do not eliminate OPSI risk 1, 7

Emergency standby antibiotics:

• All patients must keep a home supply of amoxicillin for immediate self-administration at the first sign of fever, malaise, or chills 1, 7
• Adult emergency regimen: Amoxicillin 3 g loading dose, then 1 g every 8 hours 1
• Pediatric emergency regimen: Amoxicillin 50 mg/kg divided into three daily doses 1, 7
• Beta-lactam-allergic adults: Levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily 1
• After initiating standby antibiotics, patients must proceed immediately to the emergency department because clinical deterioration can be rapid 1, 7

Patient Education and Identification

Every asplenic patient must receive written education, a Medic-Alert bracelet or disc, and a post-splenectomy identification card to ensure rapid recognition by healthcare personnel. 1, 7

• Educate patients about the lifelong 30-70% mortality risk of OPSI to ensure compliance with preventive measures 7, 2
• Instruct patients to seek urgent medical care for any temperature ≥38°C (101°F) 8, 1, 7
• Provide clear instructions for the use of standby antibiotics and reinforce at each clinical encounter 1, 7
• Formally notify the primary care provider of the patient's asplenic status to facilitate coordinated long-term management 1, 7

Special Circumstances Requiring Additional Antibiotics

Animal bites:

• Co-amoxiclav (amoxicillin-clavulanate) for 5 days due to high risk of Capnocytophaga canimorsus infection 1, 7
• Erythromycin for 5 days if penicillin-allergic 1

Travel to endemic areas:

• Appropriate prophylaxis for malaria, histoplasmosis, or babesiosis when traveling to endemic regions 1, 7

Tick bites:

• Counsel on babesiosis symptoms; treat confirmed infection with quinine ± clindamycin 1

High-Risk Populations Requiring Extra Vigilance

Children under 5 years have an infection rate exceeding 10% compared to <1% in adults, with neonates having >30% risk of OPSI. 1, 7

• Children <2 years should be reimmunized after age 2 due to inherently reduced antibody response 6, 7
• Patients with sickle cell disease (HbSS, HbSC) are at especially high risk 7
• Patients aged ≥65 years may benefit from more aggressive prophylaxis within the first 3 years post-splenectomy 4
• Patients with lymphoproliferative disorders, myeloma, or chronic infections require intensified surveillance 7

Critical Pitfalls to Avoid

• Vaccinating less than 14 days after emergency splenectomy results in inadequate antibody response 6, 7
• Failing to administer both MenACWY and MenB vaccines—both are required for optimal protection 6, 7
• Forgetting lifelong revaccination schedules—protection wanes and infection risk persists for life, with cases reported >20 years post-splenectomy 6, 7
• Not providing emergency standby antibiotics—patients need immediate access to antibiotics at home 1, 7
• Delaying antibiotic administration for diagnostic workup—even a brief delay can be fatal 4, 2
• Assuming vaccination provides complete protection—current pneumococcal vaccines cover only 23 of ~90 serotypes, and vaccine failures occur even with appropriate immunization 7, 4