and well-being of children and youth
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Children with asplenia or hyposplenia are at risk of developing overwhelming sepsis. Health care providers caring for children with asplenia should ensure the best outcomes by using preventive strategies that focus on parent and patient education, immunization, antibiotic prophylaxis and aggressive management of suspected infection. The present position statement offers current guidance on each of these issues and replaces a previous CPS statement, ‘Prevention and therapy of bacterial infections for children with asplenia or hyposplenia’, published in 1999.
Key Words: Antibiotic prophylaxis; Immunization; Sepsis; Splenectomy
Children can have absent or defective splenic function as a result of congenital anatomical absence of a spleen, surgical removal of the spleen, or medical conditions that result in poor or absent splenic function. Sickle cell anemia is a common cause of this condition in Canada. Absent or defective splenic function is associated with a high risk of fulminant bacterial sepsis, especially with encapsulated bacteria. Splenectomized children younger than 15 years of age and congenitally asplenic infants are at greater risk of developing overwhelming postsplenectomy sepsis than adults. Individuals with underlying blood disorders, such as hemoglobinopathies (eg, sickle cell disease, thalassemia major) or hereditary spherocytosis, are at greater risk than those who have undergone a splenectomy because of trauma. Asplenic patients are at risk of overwhelming sepsis throughout their life span, with the highest frequency of sepsis reported in the first three years postsplenectomy or the first three years of life, if congenitally asplenic. Asplenic patients with sepsis from encapsulated organisms have a 50% to 70% mortality rate, with the highest mortality rate reported in children younger than two years of age.
Most fulminant sepsis in asplenic patients is due to bacteria encapsulated by a polysaccharide capsule. Streptococcus pneumoniae is the most common organism causing sepsis and is isolated in at least 50% of cases. Haemophilus influenzae type b (Hib), Neisseria meningitidis, Salmonella species and Escherichia coli are also common. Less commonly, Pseudomonas, Klebsiella, streptococci and staphylococci are found. Limited data suggest that in the first three months of life, coliform (E coli or Klebsiella) sepsis occurs more frequently. Overwhelming sepsis associated with cat and dog bites has also been reported and is caused by Capnocytophaga species. Asplenic patients are also more susceptible to severe or fatal malaria and to infection by the protozoan Babesia, which is transmitted by tick bites.
Health care providers caring for children with asplenia should ensure the best outcomes with preventive strategies: parent and patient education, immunization, antibiotic prophylaxis and aggressive management of suspected infection.
Although immunization and prophylactic antibiotics are effective, they do not provide complete protection. Children with asplenia and their families must be educated about the risk of sepsis and instructed to seek medical attention promptly when the child is ill or has a fever. Heightened infection risk continues into adulthood. Recognizing postsplenectomy sepsis can be difficult and death may occur in a matter of hours. The importance of using prophylactic antibiotics and vaccines should be emphasized repeatedly.
Vulnerable patients should wear a MedicAlert bracelet. When travelling, they should carry a note from their physician stating their diagnosis, associated risks and a suggested medical management plan should they become ill. They should be aware of their increased risk of infection after animal bites, especially with Capnocytophaga canimorsus from dog bites, and must be given appropriate antibiotics, such as amoxicillin-clavulanic acid, if they are bitten.
All patients should receive the standard childhood and adolescent immunizations at the recommended age. However, due to the risk of fulminant sepsis from encapsulated bacteria, immunizations against S pneumoniae, Hib and N meningitidis should be ensured, and may be administered on an earlier schedule than is routine. Conjugated vaccines activate a superior immune response compared with polysaccharide vaccines. Studies of group A and C meningococcal polysaccharide vaccine and repeated doses of PPV23 in adults and children have shown that a state of immune tolerance, or hyporesponsiveness, can develop in response to repeated polysaccharide vaccine antigen exposures. Thus, conjugate vaccines are used preferentially whenever possible.
All asplenic patients should receive both the conjugated 13-valent pneumococcal vaccine and the 23-valent polysaccharide vaccine.
All asplenic patients should receive conjugate quadrivalent meningococcal vaccine (MCV4). There are currently three products available in Canada. Menveo (Novartis, Canada) can be used from two months of age and either Menveo, Menactra (Sanofi Pasteur, Canada) or Nimenrix (GlaxoSmithKline, Canada) can be used after 24 months of age.
When a patient is undergoing an elective or semielective splenectomy, there is some evidence that the best responses occur when vaccines are administered at least two weeks before the surgery is performed. When this timing is not possible, it is optimal to start immunizations at least two weeks postsplenectomy. However, in situations for which vaccines are not administered before splenectomy, the benefit of waiting two weeks postsplenectomy must be carefully weighed against the possibility that the patient may not be vaccinated at all; sometimes the best choice is to vaccinate the child before discharge from hospital.
Immunizations do not fully protect against infections with encapsulated bacteria, making antibiotic prophylaxis a second, vital aspect of care. Table 1 provides dosing information for antibiotic prophylaxis. Because S pneumoniae is the most common cause of severe infections in children with asplenia or hyposplenia, with significant associated mortality, patients younger than five years of age should all receive antibiotic prophylaxis.
Birth to three months
Amoxicillin/clavulanate 10 mg/kg/dose two times per day, with penicillin VK 125 mg two times per day OR amoxicillin 10 mg/kg/dose two times per day being an alternative if not tolerated
Escherichia coli, Klebsiella are of concern in this age group
>3 months to five years
Penicillin VK 125 mg per dose two times per day OR amoxicillin 10 mg/kg/dose two times per day
Liquid amoxicillin may be better tolerated than liquid penicillin because it tastes better
Penicillin V 250 mg or 300 mg per dose two times per day OR amoxicillin 250 mg per dose two times per day
For penicillin, 250 mg is a convenient dose for suspension but tablets are only available as 300 mg
*For penicillin anaphylaxis, refer the patient for allergy testing and administer erythromycin pending results
Controversies exist with respect to optimal antibiotic prophylaxis. Topics include the degree of patient compliance, optimal duration and the effect of prophylaxis on the emergence of penicillin-resistant pneumococci. The single prospective controlled study that showed an 84% reduction in infection was conducted in a population of patients with sickle cell disease; these findings may not apply to all patients with poor splenic function. Also unclear is whether it is necessary to cover coliforms for the first three months of life; the studies that led to this recommendation involved very small numbers of infants with bacteremia.
The age at which antibiotic prophylaxis should be discontinued is the most controversial topic. The Red Book from the American Academy of Paediatrics recommends prophylaxis until the child is five years of age and a minimum of one year of prophylaxis for children older than five years of age postsplenectomy, provided the child has received all the appropriate pneumococcal vaccinations. The British Committee for Standards in Haematology General Haematology Task Force recommends that lifelong prophylactic antibiotics should be offered in all cases and especially encouraged for children younger than 16 years of age and for all age groups in the first two years postsplenectomy or where there is an underlying immune function impairment.
Because most postsplenectomy sepsis occurs within the first two to three years after surgery, the Canadian Paediatric Society’s Infectious Diseases and Immunization Committee recommends antibiotic prophylaxis for a minimum of two years postsplenectomy and for all children <5 years of age. Furthermore, because fulminant septicemia has been reported in adults up to 65 years postsplenectomy, and invasive infection with penicillin-resistant pneumococci has not emerged as a problem for patients on long-term penicillin prophylaxis, lifelong prophylaxis in all cases is ideally recommended. However, the patient’s or family’s compliance and degree of access to medical care, current pneumococcal resistance rates and previous episodes of life-threatening sepsis must be considered when making or reviewing this decision.
Children who have had or are believed to have had an anaphylactic-type reaction to penicillin should be referred immediately to an allergist to verify the diagnosis and for challenge or desensitization as warranted. Erythromycin is a recommended alternative; however, this antibiotic is less successful at preventing invasive disease because of higher rates of pneumococcal resistance.
The optimal duration of antibiotic prophylaxis for children who undergo partial splenectomy or who have functional asplenia or polysplenia is unclear from the literature. Until there are recommendations to the contrary, following the guidelines described for children undergoing total splenectomy appears to be the most prudent course.
Asplenic and hyposplenic children must be advised of their increased risk of severe malaria and should always seek travel advice. They should also take malaria prophylaxis as appropriate for their age and the type of malaria found in the area to which they are travelling. Preventive measures should be taken, including sleeping under an insecticide-treated bed net or in air-conditioned accommodations, and using insect repellent. Within the first month of returning from a malarious area, and for up to a year afterward, the patient with fever should inform their health care provider and malaria should be included in the differential diagnosis.
Children with asplenia must be seen by a physician immediately for every febrile illness. Sepsis in individuals with asplenia or hyposplenia is a medical emergency because they can die within several hours of fever onset despite appearing well initially. Unless there is an obvious nonbacterial source, a blood culture should be performed but should not delay the administration of antibiotic therapy. All patients should receive ceftriaxone (100 mg/kg/dose, maximum 2 g/dose). Where intermediate or high penicillin-resistant pneumococci are prevalent, administer both ceftriaxone and vancomycin (60 mg/kg/day in divided doses every 6 h). If the patient is being treated in a clinic or office setting, refer immediately to the nearest emergency department. Clinical deterioration can be rapid even after antibiotic administration. Antibiotics should be modified once blood culture results become available.
If the patient has a serious penicillin or cephalosporin allergy, vancomycin and ciprofloxacin can be used. Antibiotics should be modified once blood culture results become available.
To prevent and treat infections in children with asplenia or hyposplenia, the Canadian Paediatric Society recommends that:
This position statement has been reviewed by the Community Paediatrics Committee of the Canadian Paediatric Society.
CPS INFECTIOUS DISEASES AND IMMUNIZATION COMMITTEE
Members: Robert Bortolussi MD (past Chair); Natalie A Bridger MD; Jane C Finlay MD (past member); Susanna Martin MD (Board Representative); Jane C McDonald MD; Heather Onyett MD; Joan L Robinson MD (Chair); Marina I Salvadori MD (past member); Otto G Vanderkooi MD
Liaisons: Upton D Allen MBBS, Canadian Pediatric AIDS Research Group; Michael Brady MD, Committee on Infectious Diseases, American Academy of Pediatrics; Charles PS Hui MD, Committee to Advise on Tropical Medicine and Travel (CATMAT), Public Health Agency of Canada; Nicole Le Saux MD, Immunization Monitoring Program, ACTive (IMPACT); Dorothy L Moore MD, National Advisory Committee on Immunization (NACI); Nancy Scott-Thomas MD, The College of Family Physicians of Canada; John S Spika MD, Public Health Agency of Canada
Consultant: Noni E MacDonald MD
Principal authors: Marina I Salvadori MD, Victoria E Price MBChB MMED
Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.