Infectious disease evaluation of infants and children awaiting solid organ or hematopoietic stem cell transplant

Basic principles of the infectious disease pretransplant evaluation

The pretransplant infectious disease evaluation represents the first step in a long continuum of infection prevention that extends into the posttransplant period. This evaluation is a critical element in the pretransplant process and should be performed as early as possible, ideally as soon as a child is considered for transplant. The overall objectives of infectious disease evaluation are to (1) identify and mitigate infectious complications that may result in delay of transplant; (2) identify risk factors that may affect perioperative management; (3) identify posttransplant prevention strategies for specific risks; and (4) begin the discussion of long-term strategies for safer living in the posttransplant period. The evaluation should be comprehensive and not limited to basic serologic screening. A key guiding principle is that pretransplant screening tests should be performed to address those infections that may increase the risk of posttransplant complications and that will prompt specific intervention either in the pretransplant or posttransplant period. A dedicated infectious disease evaluation before transplant is a critical opportunity to review all prior and current infections and antimicrobial use that are likely to affect the transplant course and management, including unrecognized or latent infections.

It is especially important that pediatric transplant candidates receive an infectious disease review that is family-centered and considers occupational and recreational exposures not only for the transplant candidate but also for all other household contacts. Household water sources and dietary habits should be reviewed to identify risk factors such as well water exposure or ingestion of uncooked meat or fish. Travel history and animal exposures should be reviewed and discussed. For families with pets, guidance for living with animals after transplant is available through the U.S. Centers for Disease Control and Prevention and should also be discussed. Children who live in areas of higher tuberculosis (TB) prevalence and/or who live in households with adults with active TB infection are at high risk for acquisition of TB infection before and after transplant. TB risk factors should be reviewed for all household contacts, with additional TB screening and treatment measures for household contacts as indicated, as discussed in more detail in the following text.

Pretransplant infectious disease evaluation also provides an important opportunity to review and update immunizations for both the transplant candidate and household contacts. It is important to note that live attenuated vaccines for varicella, measles, mumps, and rubella are not contraindicated for household contacts of transplanted children, and ensuring that household contacts are fully immunized is a critical preventative strategy for children who receive transplants and who may be susceptible secondary to incomplete immunization or waning immunity after immunization. This “cocoon” immunization strategy is essential for household contacts of pediatric transplant candidates and recipients during influenza season.

The risk of donor-derived infection should also be discussed as part of the infectious disease pretransplant evaluation. This is a complex and multifaceted conversation that may be best approached across multiple visits with both an infectious disease consultant and the primary transplant team. Although families and providers alike are often concerned about the potential risk of human immunodeficiency virus (HIV) and hepatitis transmission via donors who are considered to be at either routine or increased risk by U.S. Public Health Service criteria, it is also important to discuss the risk of other donor-derived infections, both unanticipated and expected. This includes infections for which donors may be screened ( Strongyloides stercoralis , Toxoplasma gondii , Trypanosoma cruzi ) but also for donor infections that may be unrecognized at the time of transplant. Risk and implications of donor-derived infections that are often anticipated, such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV), should also be discussed, especially for transplant candidates who are presumed to be uninfected by these viruses based on pretransplant screening serology.

The first step in the pretransplant infectious disease evaluation of both pediatric solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) candidates is a comprehensive review of how the child’s underlying disease affects their risk of infection before and after transplant. For transplant candidates with a history of malignancy, the status of the child’s disease should be documented (remission or relapse), and prior chemotherapy and radiotherapy regimens should be reviewed. Both HSCT and SOT candidates may have a history of exposure to immunosuppressive agents, such as glucocorticoids or anti-CD20 monoclonal antibody; therefore recent serum immune globulin levels and quantitative lymphocyte subsets should be reviewed as indicated. The presence of a foreign body, prosthetic material, or structural abnormality (central venous or hemodialysis catheter, prosthetic joint, vascular graft, ureteral stent, hemodialysis graft fistula) should be documented. Prior imaging should be reviewed to assess for lung nodules, calcified granulomas, or cavitary lesions that may prompt further investigation before transplant.

Review of the child’s underlying disease is followed by a comprehensive review of all prior and current infections and bacterial colonization history. Pediatric transplant candidates with a history of malignancy may have a history of bacteremia or invasive fungal infection), and children awaiting HSCT for primary immune deficiency may have an extensive history of opportunistic infections. Kidney transplant candidates may have a history of urinary tract infection, and hemodialysis and peritoneal dialysis recipients are at higher risk for catheter-related bacteremia and peritonitis, respectively. Hardware-associated infections may develop in heart transplant recipients who require ventricular assist device support, and ascending cholangitis or peritonitis may develop in children with liver failure. Lung transplant candidates with cystic fibrosis may have a history of respiratory colonization with multidrug- or extensively drug-resistant organisms such as Pseudomonas aeruginosa , Burkholderia cepacia , and Stenotrophomonas maltophilia . Thus special attention should be paid to prior bacterial culture and susceptibility results, as well as to prior antimicrobial utilization. Baseline sputum cultures are recommended for lung transplant candidates to identify colonizing organisms and their antimicrobial susceptibility patterns.

For transplant candidates who have a poorly documented history of allergic reaction to a specific antimicrobial, this history should be clarified. Formal allergy consultation should be completed as needed before transplant. Dental history should also be reviewed, and ideally, candidates should undergo complete dental evaluation and appropriate intervention before transplant.