2025 – PAGE 314 – INFECTIOUS DISEASES

(DOUBLE TAKE) VARICELLA ZOSTER VIRUS (CHICKEN POX)

The varicella zoster virus causes CHICKEN POX. A chicken pox lesion may be described as a “dew drop on a petal” during the vesicle phase. Lesions are said to come in “crops” at different times, and will therefore appear in different stages on the body (some vesicles, some crusted lesions). The rash goes to the TRUNK and then to the FACE and EXTREMITIES. It lasts for 7–10 days and leaves minimal scars. Congenital varicella may present with scars from the intrauterine infection, limb hypoplasia, ocular defects (e.g., chorioretinitis, microphthalmia, cataracts), neurologic issues (e.g., microcephaly, seizures, developmental delays), and low birth weight.

PEARL: VZIG (VZV immunoglobulin) is given for prophylaxis to newborns if the mom developed symptoms within FIVE days prior to delivery and TWO days after delivery. If symptoms started six days prior to delivery, then chances of vertical transmission are low and NO PROPHYLAXIS IS NEEDED. Congenital varicella syndrome can result in low birth weight as well as CNS, eye and skin abnormalities.

PEARL: Any immunocompromised patient should avoid contact with patients who have a case of the chicken pox.

NOTE: It’s doubtful you will need to know about the smallpox virus (Variola). In case you do, just know that the lesions all appear at the SAME TIME, so all lesions will look similar. Other facts include –> limited to face/extremities, lasts up to 3–4 weeks and leaves lots of scarring.

(DOUBLE TAKE) MNEMONIC: Imagine a patient who is bored because he’s stuck in a NEGATIVE PRESSURE ISOLATION room, and the only channel he gets to watch is MTV. Negative pressure isolation is required for Measles, Mycobacterium Tuberculosis and Varicella. As mentioned in the Aspergillus section, that, too, requires negative pressure isolation.

HUMAN IMMUNODEFICIENCY VIRUS (HIV)

Consider HIV in any child with cognitive impairment, FTT, opportunistic or frequent infections, thrush, hepatosplenomegaly, fevers, night sweats, or weight loss. It can present in the first year with HIGH levels of immunoglobulins (which are dysfunctional) and later in life with abnormally LOW immunoglobulins. CD4/helper T cell count should be LOW. The primary mode of transmission for kids is vertical. Pregnant women with HIV should get antiretroviral therapy (ART) with Zidovudine or Nevirapine to possibly prevent the vertical transmission. For higher risk babies (born to a mother with no prenatal care, inadequate ART, new HIV infection during pregnancy, detectable viral load at the time of delivery, etc.), get an immediate DNA PCR (not RNA PCR, which is for a viral load) at birth and at 2-3 weeks of age. For lower risk babies, testing can start at age 2-3 weeks. All babies born to mothers with HIV get 2 additional tests. One at the 1-month or 2-month well-child visit and another at the 4-month or 6-month well-child visits. If all are negative, the patient is probably negative. If any are positive, repeat to confirm.

• CHEMOPROPHYLAXIS: If the mother’s viral load is undetectable, give Zidovudine prophylaxis within 72 hours of birth (ideally within 6-12 hours) for 2-4 weeks. If mother’s viral load is detectable, provide combination ART for presumptive treatment.
• HIV TESTING: Maternal antibodies can persist for up to 18 months. Therefore, antibody tests are screening tests in infants and young children. The enzyme immunoassay (EIA) is an antibody test. EIA, or the “rapid antibody test,” should be done in children of mothers with HIV at 12-18 months of age to ensure that the maternal antibodies have cleared. If the result is positive, then a confirmatory test which looks for HIV genetic material should be done. A Western Blot, immunofluorescence assay (IFA), nucleic amplification testing (NAT) or polymerase chain reaction (PCR) are all possible answers for this age range on the ABP exam. In older children, antibody testing may be used for diagnosing HIV.
• BACTRIM PROPHYLAXIS: Once a child is diagnosed with HIV, start PCP (AKA PJP) prophylaxis regardless of what the CD4 count is.
• NEEDLE STICKS: If you get stuck with a needle from an HIV patient, you get a 2-drug or 3-drug regimen for pro­phy­laxis. A 3-drug regimen is generally preferred: tenofovir/emtricitabine PLUS dolutegravir OR raltegravir.
• VACCINATIONS: MAY GIVE MMR, VZV, and FLU vaccines as long as there is only mild immunosup­pres­sion.
• DRUGS: It’s doubtful the certification exam would ask you about a drug regimen, but the boards might ask about HIV medication side effects. They include pancreatitis, Stevens-Johnson syndrome, liver toxicity, pneu­mo­nitis, CNS effects (neuropathy), neutropenia, and renal problems (insufficiency and stones).
  • PEARL: The “d” drugs (ddI & ddC) cause pancreatitis.
  • MNEMONIC: Just imagine flipping the “d” upright to make a “p” for pancreatitis!