Preventing and treating infections in children with asplenia or hyposplenia

Question 1

Which types of patients are at greater risk of overwhelming sepsis?

Answer 1

• Splenectomized patients < age 15: greatest risk in the first 3 years following surgery
• Congenitally asplenic infants: greatest risk in the first 3yrs of life
• Patients with underlying blood disoders at greater risk than patients who are asplenic following trauma

Question 2

What is the mortality rate of asplenic patients with sepsis from encapsulated organisms?

Answer 2

• 40-70%
• Highest mortality rate reported in children < 2 years of age

Question 3

What is the most common organism causing sepsis in asplenic patients?

Answer 3

• Streptococcus pneumoniae isiolated in 50% cases
• Other common bugs: HIB, Neisseria meningitidis, salmonella species and E. coli
• Less commonly: Pseudomonas, klebsiella, streptococci

Question 4

What bugs are most likely to cause sepsis in the first three months of life?

Answer 4

• E. coli and klebsiella

Question 5

What parasites are asplenic patients more susceptible to?

Answer 5

• Malaria
• protozoan Babesia transmitted by tick bites

Question 6

What should patients and families be educated about?

Answer 6

• Risk of sepsis so they know to seek medical attention when their kid is ill or febrile
• Importance of prophylactic antibiotics and vaccination to prevent sepsis
• Patients should wear a medic alert bracelet
• Carry a physician note when travelling stating diagnosis, risks and suggested medical management plan

Question 7

What infection are asplenic patients susceptible to following animal bites?

Answer 7

• Capnocytophaga canimorsus
• Should receive prophylactic amoxiclav following animal bites

Question 8

How should asplenic patients be vaccinated?

Answer 8

• Should receive all vaccines according to usual schedule
• In addition need vaccines against encapsulated organisms (s. pneumo, meningococcus, HIB) administered on an earlier schedule

Question 9

What type of vaccinations are preferred?

Answer 9

• Conjugated vaccines induce superior immune response compared to polysaccharide vaccines
• Some evidence shows a state of immune tolerance develops following repeated vaccinations with polysaccharide vaccines

Question 10

How should asplenic patients be vaccinated against pneumococcus?

Answer 10

• Regular vaccine series PCV13 at 2, 4, 6, 12-15 months
• Kids 12-24 mos who have never received PCV13 ened two doses at least 8 weeks apart
• Unvaccinated patients > 24 months only need one dose
• Even if kids got all doses of PCV7 and PCV10 they still need one dose of PCV13 ASAP
• PPV23 should be given ASAP after 24 months
• Prime the immune system with conjugated protein vaccine followed by polysaccharide vaccine
• Give booster dose of PPV23 5 years after first dose
• If an asplenic patient only got one dose of PPV23 they should get a dose of PPV13 1 year later

Question 11

How should asplenic patients be vaccinated against meningococcus?

Answer 11

• All asplenic patients should get conjugate quadrivalent meningococcal vaccine (MCV4)
• 4 types of MCV4 available: Menveo, Menactra, Nimenrix
• Asplenic infants should get Menveo at 2, 4, 6, 12-15 months
• Asplenic kids identified at 12-23 months of age should get two doses of Menveo 8 weeks apart
• Asplenic kids > 2yrs need 2 doses of any MCV4 8 weeks apart
• Patients vaccinated with MCV4 need booster shots every 5 years
• No role for meningococcal polysaccharine vaccine (Menomune)
• All asplenic patients should get Bexsero (4 component meningococcal vaccine against serotype B)

Question 12

How should asplenic patients be vaccinated against HIB?

Answer 12

• Primary series at 2, 4, 6, 18 months
• All patients > 5 yrs who have never received HIB or who have missed a dose should get one dose
• Some experts think asplenic kids > 5 years should get one additional dose of HIB even if previously vaccinated
• Asplenic kids who present with a life threatening HIB infection should receive HIB vaccine because the infection iteself does not provide life long protection

Question 13

How should asplenic patients be vaccinated against influenza?

Answer 13

Yearly seasonal influenza vaccine starting at six months of age to lower the risk of secondary bacterial infections

Question 14

How should asplenic patients be vaccinated while travelling?

Answer 14

• Vaccination against salmonella typhi
• Antimalarial prophylaxis

Question 15

How should household contacts of asplenic patients be vaccinated?

Answer 15

Household contacts should receive all age appropriate vaccines and the yearly influenza vaccine

Question 16

How should a patient be vaccinated against encapsulated organisms prior to splenectomy?

Answer 16

• Vaccines should be administered at least 2 weeks before splenectomy
• If not possible to vaccinate pre-op, can vaccinate post op at least two weeks following surgery

Question 17

Why do kids need antibitic prophylaxis?

Answer 17

• S. pneumoniae is the most common casue of secere infections in asplenic kids and is associated with significant mortality

Question 18

What is the best antibiotic prophyaxis for an asplenic patient from birth to three months?

Answer 18

• Amoxi-clav 10mg/kg/dose BID wtith penicillin VK 125mg BID OR
• Amoxicillin 10mg/kg/dose BID if the above is not tolerated
• E. coli and Klebsiella especially concerning in this age group

Question 19

What is the recommended antibiotic prophylaxis for asplenic patients >3 mos - 5 years?

Answer 19

• Penicillin VK 125mg BID OR
• Amoxicillin 10mg/kg/dose BID

Question 20

What is the recommended antibiotic prophylaxis for asplenic patients > 5 years?

Answer 20

• Penicillin V 250-300mg BID OR
• 250 = suspension / 300 = tablets
• Amoxicillin 250mg BID

Question 21

When can antibiotic prophylaxis stop?

Answer 21

• CONTROVERSIAL!
• AAP: at age 5 or one yr post splenectomy in kids > 5 at the time of splenectomy
• British Task Force: lifelong prophylaxis recommended
• CPS: minimum 2 years post splenectomy and for all kids < 5 years realistically but lifelong prophylaxis ideal as fulminant septicemia seen in patients up to age 65
• Lifelong prophylaxis for all patients weho have had an episode of life threatening pneumococcal sepsis!!

Question 22

What to do with asplenic kids with allergies to penicillin?

Answer 22

• Immediate referral to allergist for diagnosis, challenge, desensitization
• Erythromycin is a good alternative

Question 23

How long to prophylax kids who have undergone partial splenectomy?

Answer 23

Follow same guidelines as for kids who have undergone total splenectomy

Question 24

How to manage a febrile asplenic patient?

Answer 24

• Immediate blood culture and administration of ceftriaxone (100mg/kg/dose, max 2g)
• If living in an area with high prevalence of PCN resistant pneumococci, give ceftriaxone and vancomycin (60mg/kg/day divided Q6H)
• If anaphylaxis to cephalosporins can use vanco and ciprofloxacin