What are the most common causes of pneumonia in patients post-splenectomy (removal of the spleen)?

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Last updated: June 30, 2025View editorial policy

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From the Guidelines

The most common causes of pneumonia in patients post-splenectomy are encapsulated bacteria, particularly Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis, which can lead to overwhelming post-splenectomy infection (OPSI) and severe pneumonia. These pathogens are especially dangerous for asplenic patients because the spleen plays a crucial role in filtering and removing encapsulated bacteria from the bloodstream [ 1 ]. Without a spleen, patients have reduced ability to clear these organisms, leading to severe infections. Streptococcus pneumoniae is the most prevalent pathogen, responsible for approximately 50% of cases [ 1 ]. Other significant pathogens include Haemophilus influenzae type B and Neisseria meningitidis.

Prevention and Management

To prevent pneumonia and other infections in post-splenectomy patients, the following measures are recommended:

  • Vaccination against encapsulated bacteria, including pneumococcal, Haemophilus influenzae type b, and meningococcal vaccines, should be administered at least 2 weeks before splenectomy or as soon as possible after surgery [ 1 ].
  • Annual influenza vaccination is also recommended for all patients over 6 months of age [ 1 ].
  • Patients should be educated about the lifelong risk of infection and the need to seek immediate medical attention when febrile.
  • Antibiotic prophylaxis may be necessary in some patients, especially in the first few years after splenectomy or in high-risk patients [ 1 ].
  • In cases of sudden onset of unexplained fever, malaise, chills, or other constitutional symptoms, patients should be treated with antibiotics, such as amoxicillin or levofloxacin, as soon as possible [ 1 ].

Key Considerations

  • The risk of OPSI and associated death is highest in the first year after splenectomy, but remains elevated for more than 10 years and probably for life [ 1 ].
  • Asplenic/hyposplenic patients, especially children under 5 years old, have a greater overall risk of OPSI and increased death compared to adults [ 1 ].
  • Community physicians should be aware of the asplenic/hyposplenic condition to provide the most appropriate level of care [ 1 ].

From the Research

Most Common Causes of Pneumonia in Patients Post-Splenectomy

The most common causes of pneumonia in patients post-splenectomy are infections caused by encapsulated bacteria, including:

  • Streptococcus pneumoniae 2, 3, 4, 5, 6
  • Haemophilus influenzae type b (Hib) 2, 3, 5, 6
  • Neisseria meningitidis 2, 3, 5, 6

Prevention Measures

To prevent these infections, several measures are recommended, including:

  • Vaccination against Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis 2, 3, 5, 6
  • Antibiotic prophylaxis, such as phenoxymethyl-penicillin, for at least 2 years post-splenectomy 3, 6
  • Education on prevention measures and infectious risk 3, 6
  • Carrying a medical alert and an up-to-date vaccination card 3, 6

Risk Factors

Patients post-splenectomy are at increased risk of developing overwhelming postsplenectomy infection (OPSI), which has a mortality rate of up to 50% 3, 6. The risk of OPSI is higher in patients who do not receive recommended vaccinations and antibiotic prophylaxis 2, 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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