OTHER





Risk factor Comment
Trauma
  • Trauma to the spleen can cause life-threatening bleeding
  • Splenectomy may be necessary
Immune thrombocytopenia (ITP)
  • In ITP, the spleen removes antibody-coated platelets which leads to thrombocytopenia
  • Splenectomy is a preferred treatment for chronic ITP
Sickle cell anemia
  • Sickling leads to infarction of the spleen
  • In sickle cell patients, functional asplenia typically develops by 1 year of age, and anatomical asplenia (spleen atrophy) develops by 6 - 8 years of age
Chronic graft vs host disease
after bone marrow transplant
  • May lead to functional hyposplenism
Celiac disease
  • Celiac disease is the most frequent disorder associated with hyposplenism. Hyposplenism is present in 33 - 76% of celiac patients.
  • Gluten-free diet can restore splenic function
  • Splenic atrophy is an indicator of poor prognosis in celiac patients
Hereditary spherocytosis
  • Hereditary disorder of the red blood cell membrane that leads to hemolytic anemia
  • Splenectomy is the preferred treatment for moderate or severe disease
Spleen irradiation
  • Splenic irradiation is sometimes used to treat myeloproliferative neoplasms
HIV
  • HIV infection can lead to functional hyposplenism
  • Effective antiretroviral therapy helps prevent
Congenital asplenia
  • Rare condition
  • Often associated with other abnormalities



Infections in asplenic/hyposplenic patients
Organism Comment
Streptococcus pneumoniae
  • Encapsulated bacteria
  • Most common cause of sepsis in asplenic patients (50 - 90% of cases)
  • Symptom onset is typically nonspecific (fever, sore throat, muscle aches, nausea, vomiting) with no localized focus of infection
  • Vaccines (PCV13 and PPSV23) can help prevent
Haemophilus influenzae
type b
  • Encapsulated bacteria
  • Primarily affects children. Incidence has decreased greatly since the universal use of Hib conjugate vaccine.
  • Hib conjugate vaccine can help prevent
Neisseria meningitidis
  • Encapsulated bacteria
  • Disease is more prevalent in certain regions (e.g. sub-Saharan Africa)
  • Often occurs in outbreaks
  • Vaccines (MenACWY, MPSV4, MenB) can help prevent
Malaria
  • Fatal cases of overwhelming malaria infection have been reported in asplenic/hyposplenic patients
  • Proper prophylaxis (e.g. medications, mosquito repellent) should be taken when traveling to endemic regions
Capnocytophaga species
(canimorsus and cynodegmi)
  • Transmitted by dog and cat bites
  • Cases of sepsis have occurred in asplenic patients
Babesiosis
  • Protozoan transmitted by tick bite
  • Endemic in Northeast and Upper Midwest United States
  • Asplenic/hyposplenic patients may be at increased risk of fulminant infection



Method Comment
Technetium-99m-labelled heat-damaged autologous erythrocyte clearance
  • Gold standard for measuring spleen function
  • Measures splenic uptake and clearance of heat-damaged erythrocytes
  • Expensive and not widely available
Detection of Howell-Jolly bodies
  • Howell-Jolly bodies are clusters of nuclear remnants (DNA) in erythrocytes
  • Howell-Jolly bodies are typically removed by the spleen
  • Easily detected on peripheral blood smear
  • Imprecise for quantifying spleen function
Spleen imaging
  • Detection of spleen atrophy on imaging (e.g. CT scan, ultrasound) may indicate hyposplenism
  • No good studies have evaluated the correlation between spleen size and function
Measurement of pitted erythrocytes
  • Pitted erythrocytes have pits on their cell membrane. The spleen typically removes the pits.
  • A special microscope can detect pitted erythrocytes. Increases in pitted erythrocytes correlate well with decreased spleen function.
  • Test is simple to perform, but requires special equipment



Recommended immunizations for asplenic/hyposplenic patients
*For patients undergoing elective splenectomy, vaccinations should be completed
at least 2 weeks before surgery if possible
Vaccination Schedule
Streptococcus pneumoniae PCV13 (Prevnar 13)
  • Give one dose of PCV13 if not previously vaccinated
    • PCV13 is part of the recommended childhood immunization schedule (age 2, 4, 6, and 12 months)
    • A one-time dose of PCV13 is recommended in all adults at age 65 years
    • PCV13 became available in the U.S. in 2010

PPSV23 (Pneumovax 23)
  • Give one dose of PPSV23 at least eight weeks after PCV13 is given
  • Give a second PPSV23 dose 5 years after the first dose.
    • A one-time dose of PPSV23 is recommended in all adults at age 65 years
    • See CDC schedule for recommendations on patients who received PPSV23 before PCV13
Hib conjugate vaccine
  • Give one dose of Hib conjugate vaccine if not previously vaccinated
  • Hib conjugate vaccine is part of recommended childhood immunization schedule (age 2, 4, 6, and 12 months)
  • The Hib conjugate vaccine became available in the U.S. in 1987
Neisseria meningitidis ADULTS
    Menveo or Menactra (both abbreviated MenACWY)
    • Give 2 doses at least 2 months apart. Revaccinate every 5 years.
    • Menveo and Menactra contain serogroups A, C, Y, and W135
    Bexsero (MenB-4C) or Trumenba (MenB-FHbp)
    • Give one of the vaccine series. MenB-4C is 2 doses given one month apart. MenB-FHbp is 3 doses given at 0, 1-2, and 6 months.

CHILDREN
    Menveo or Menactra (both abbreviated MenACWY)
    • Immunization schedule depends on age
    • Three vaccine are acceptable - Menveo (ACYW), Menactra (ACYW), and MenHibrix (CY and Hib)
    • See CDC childhood immunization schedule for recommended schedules
    Bexsero (MenB-4C) or Trumenba (MenB-FHbp)
    • Give one of the vaccine series at ≥ 10 years old. MenB-4C is 2 doses given one month apart. MenB-FHbp is 3 doses given at 0, 1-2, and 6 months (if the second dose of MenB-FHbp is administered at an interval of ≥ 6 months, a third dose does not need to be administered).
Influenza vaccine
  • All patients should receive yearly influenza vaccine
  • Influenza infection confers an increased risk of bacterial pneumonia


Antibiotic prophylaxis in asplenic/hyposplenic patients
Source Recommendation
American Academy of Pediatrics Recommendation
  • Prophylaxis until the age of 5 years, and prophylaxis for at least one year after splenectomy, regardless of age
Regimen
  • < 5 years Pen VK 125 mg two times a day OR Amoxicillin 10 mg/kg/dose two times a day
  • ≥ 5 years: Pen VK 250 mg two times a day OR Amoxicillin 10 mg/kg/dose two times a day
  • Pen allergic: erythromycin
Canadian Pediatric Society Recommendation
  • Prophylaxis until the age of 5 years, and prophylaxis for at least two years after splenectomy, regardless of age
  • Patients who experience an episode of invasive pneumococcal disease should receive longer prophylaxis
  • Lifelong prophylaxis should be considered in all patients
Regimen
  • Birth to 3 months: Amoxicillin/clavulanate 10 mg/kg/dose two times a day + Pen VK 125 mg two times a day OR Amoxicillin 10 mg/kg/dose two times a day if other regimen is not tolerated
  • 3 months to 5 years: Pen VK 125 mg two times a day OR Amoxicillin 10 mg/kg/dose two times a day
  • > 5 years: Pen VK 250 mg two times a day OR Amoxicillin 250 mg two times a day
  • Pen allergic: erythromycin
British Committee for Standards in Haematology Recommendation
  • Lifelong prophylaxis should be offered to patients who are considered high risk for infection
    • Patients at high risk for infection include the following:
      • Age < 16 years or > 50 years
      • Inadequate serological response to pneumococcal vaccination
      • History of previous invasive pneumococcal disease
      • Splenectomy for underlying haematological malignancy particularly in the context of ongoing immunosuppression
Regimen
  • Penicillins are preferred. No dosing is given.