SUPPORTIVE CARE OF CHILDREN WITH CANCER: PROPHYLAXIS AGAINST VIRUSES
Common viral infections that are known to have increased virulence in immune-compromised children include varicella-zoster virus (VZV), herpes simplex virus (HSV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), hepatitis types A and B, respiratory syncytial virus (RSV), and rubeola (measles). Infection with these viruses has resulted in prolonged virus excretion, increased morbidity, and death.
A. General preexposure measures
1. At the time of diagnosis of malignancy
a. Obtain a history of immunization and previous infection with VZV, HSV, EBV, RSV, and measles.
b. Obtain viral titers against VZV (preferably using immunofluorescence antibody or a similarly sensitive technique), HSV, CMV, EBV, and, for infants < 2 years old, RSV 2. Decrease exposure
a. Do not administer live attenuated oral polio vaccine to the siblings of patients receiving chemotherapy. Killed polio vaccine may be given.
b. Notify appropriate teachers, caregivers, and friends of the risk to these children of infection with measles and VZV.
c. Prevent in-hospital exposure by preadmission screening of other hospitalized children.
d. Avoid having caregivers with active viral infection come into direct contact with immune-suppressed patients.
B. Prophylaxis against varicella-zoster virus
Indications for, and use of, varicella-zoster immune globulin.
The decision to hold chemotherapy during the incubation period for the development of varicella should be based on the intensity of exposure, the general condition of the patient, and the intensity of the chemotherapy.
If varicella develops, stop chemotherapeutic agents and start acyclovir (1500 mg/m2/day IV divided q8h) with adequate hydration.
C. Prophylaxis against herpes simplex virus
Patients with recurrent HSV infections are at increased risk of developing significant HSV infections while receiving chemotherapy or during and after bone marrow transplantation. The administration of acyclovir prophylactically may prevent or decrease the severity of recurrent HSV infection. Its use is recommended.
a. Dosage: 200-600 mg/m2/day PO divided into 3 to 6
doses or 250 mg/m2 IV q8h during periods of marked
i. Vial: 500 mg for IV use
ii. Capsule: 200 mg
c. Acyclovir may be infused in 5% dextrose, 5% dextrose/0.9% saline, Ringer's lactate, or 0.9% saline. Ensure adequate hydration.
d. Acyclovir should not be added to or infused in the
same line with blood products, protein hydrolysates or amino acids, or fat emulsions.
e. The clearance of acyclovir is markedly decreased in
neonates. The clearance in infants aged 3 to 12 months is unknown; that of infants > 1 year old is the same as
that for adults. Adjust the dosage if the patient has
renal insufficiency (the drug is excreted by the kidneys). Table 1.1 shows the dosage adjustment for
patients with renal impairment.
D. Prophylaxis against cytomegalovirus
CMV-seronegative patients who are candidates for a bone marrow transplant should receive CMV-negative or leukocyte-depleted blood products.
When CMV-seronegative blood is not available for CMV-negative patients, white cell filters must be used. Whenever possible, filtering of blood products should occur at the blood bank shortly after collection, rather than at the bedside.
E. Prophylaxis against Epstein-Barr virus
The significance of EBV infection in patients with malignancies is unknown, although children in leukemic remission have died after a hemophagocytic infection associated with EBV.
a-Interferon can prevent EBV infections in patients who have undergone renal transplantation.
3. The prevention of EBV infections in patients receiving chemotherapy is not practical.
F. Prophylaxis against infectious hepatitis types A and B
G. Prophylaxis against respiratory syncytial virus
The risk of nosocomial infection with RSV can be significantly reduced with rapid laboratory diagnosis combined with cohort nursing and the wearing of gowns and gloves for all contacts with RSV-infected children.
H. Prophylaxis against rubeola (measles)