Children with Asplenia or Hyposplenia

Question 1

What can cause absent/defective spleen function in pediatrics?

Answer 1

• Congenital absence of spleen
• Surgical removal of spleen
• Conditions that result in poor splenic function (blood disorders - hemoglobinopathies or spherocytosis)

Question 2

Major risk of asplenia? What are the most common organisms? Less common organisms?

Answer 2

Fulminant bacterial sepsis from encapsulated organisms

Encapsulated by polysaccharide capsule:

• S pneumo (most common)
• Hib
• N meningitidis
• Salmonella
• E Coli

Less common: pseudomonas, klebsiella, strep, staph

Question 3

Factors predisposing to greater risk of sepsis?

Answer 3

• Younger than 15
• Congenital asplenia
• Underlying blood disorders
• First three years post-splenectomy (or of life if congenitally asplenic)

Question 4

Mortality of sepsis in asplenic patients? What age group has highest mortalit

Answer 4

50-70% motality

Highest mortality under 2 years

Question 5

In the first 3 months of life, which organisms are most likely to cause sepsis in asplenic infants?

Answer 5

Coliforms (E Coli, klebsiella)

Question 6

Aside from encapsulated bacteria, what other infections are more common in asplenic patients?

Answer 6

Capnocytophaga species (dog and cat bites)
Severe malaria
Babesia (protozoa)

Question 7

How do the two types of vaccines compare in terms of immunogenicity?

Answer 7

Conjugated vaccines activate a better immune response - preferred!

Immune tolerance can develop in response to multiple polysaccharide vaccine antigen exposures

Question 8

For pneumococcus, what should asplenic patients receive for immunoprophylaxis?

Answer 8

Pneumococcal conjugate vaccine - Prevnar 13
- at 2, 4, 6, 12-15 months

AND

Pneumococcal polysaccharide vaccine against 23 serotypes

• after 24 months for supplemental protection
• booster after 5 years

(Rationale: prime with conjugated protein vaccine and follow with broader spectrum less immunogenic vaccine)

Question 9

Meningococcus immunoprophylaxis for asplenic patients?

Answer 9

Conjugate quadrivalent meningococcal vaccine (MCV 4) = Menveo or Menactra

• 2, 4, 6, 12-15 months
• Revaccinate every 5 years

Question 10

Hib immunoprophylaxis for asplenic patients?

Answer 10

2, 4, 6 months
Booster at 18 months
(Some experts recommend additional dose of Hib vaccine for asplenic patients > 5 years even if fully immunized)

Question 11

If patient found to be asplenic 12-24 months, approach to vaccination?

Answer 11

Pneumococcus:

• 2 doses of PCV13 (conjugate) 8 weeks apart
• PPV23 (polysaccharide) after 24 months
• PPV 23 booster after 5 years

Meningococcus:

• 2 doses of MCV4, 8 weeks apart
• Revacc every 5 years

Hib: routine series

Question 12

If patient found to be asplenic after 24 months, approach to vaccination?

Answer 12

Pneumococcus

• 1 dose of PCV 13
• PPV 23 after 24 months
• PPV 23 booster after 5 years

Meningococcus:

• 2 doses of MCV4, 8 weeks apart
• Revacc every 5 years

Hib: routine series

Question 13

Aside from coverage for pneumococcus/meningococcus/Hib, what other immunoprophylactic measures need to be taken for asplenic pts?

Answer 13

• Yearly flu vaccine (prevent secondary bacterial infx)
• S typhi vaccine for travel to endemic areas
• Household contacts should be fully vaccinated

Question 14

Timing for vaccines in elective/semi-elective splenectomy?

Answer 14

2 weeks pre-op recommended

if not, 2 weeks post-op

Question 15

Antibiotic prophylaxis for birth to 3 months?

Answer 15

Clavulin (10 mg/kg/dose BID) and pen VK 125 mg BID

• or amoxicillin

Question 16

Antibiotic prophylaxis for 3 months-5 years?

Answer 16

Pen VK 125 BID or amoxicillin 10mg/kg/dose BID

Question 17

Antibiotic prophylaxis for >5 years?

Answer 17

Pen V 250 mg BID or amoxicillin 250mg BID

Question 18

How long do asplenic patients need antibiotic prophylaxis?

Answer 18

• Ideally lifelong (risk of sepsis many years post-splenectomy, low risk of pen-R pneumococci)
• At minimum: until 5 years of age or 2 years post-splenectomy

Question 19

Empiric antibiotics for asplenic pt presenting with febrile illness?

Answer 19

IV ceftriaxone 100mg/kg/dose

add vanco if lots of pen-resistant pneumococcus in area