A 2300-g (5-lb 1-oz) male newborn is delivered to a 29-year-old primigravid woman. The mother has HIV and received triple antiretroviral therapy during pregnancy. Her HIV viral load was 678 copies/mL 1 week prior to delivery. Labor was uncomplicated. Apgar scores are 7 and 8 at 1 and 5 minutes respectively. Physical examination of the newborn shows no abnormalities. Which of the following is the most appropriate next step in management of this infant?

Administer zidovudine, lamivudine and nevirapine

Administer lamivudine and nevirapine

A 33-year-old HIV-positive male is seen in clinic for follow-up care. When asked if he has been adhering to his HIV medications, the patient exclaims that he has been depressed, thus causing him to not take his medication for six months. His CD4+ count is now 33 cells/mm3. What medication(s) should he take in addition to his anti-retroviral therapy?

Azithromycin and trimethoprim-sulfamethoxazole

Azithromycin, dapsone, and fluconazole

A 27-year-old G2P1 woman is diagnosed with an HIV infection after undergoing routine prenatal blood work testing. Her estimated gestational age by first-trimester ultrasound is 12 weeks. Her CD4 count is 150 cells/mm^3 and her viral load is 126,000 copies/mL. She denies experiencing any symptoms of HIV infection. Which of the following is appropriate management of this patient's pregnancy?

Avoidance of antibiotic prophylaxis

A 3-month-old boy presents to his pediatrician with persistent diarrhea, oral candidiasis, and signs and symptoms of respiratory syncytial virus (RSV) pneumonia. He is very lean with weight in the 10th percentile. His blood pressure is 105/64 mm Hg and heart rate is 84/min. He is being evaluated for an immunodeficiency. Laboratory results for HIV are negative by polymerase chain reaction (PCR). Which of the following is the most likely cause of this child’s presentation?

Grossly reduced levels of B cells

An X-linked inheritance of HLA genes

A student health coordinator plans on leading a campus-wide HIV screening program that will be free for the entire undergraduate student body. The goal is to capture as many correct HIV diagnoses as possible with the fewest false positives. The coordinator consults with the hospital to see which tests are available to use for this program. Test A has a sensitivity of 0.92 and a specificity of 0.99. Test B has a sensitivity of 0.95 and a specificity of 0.96. Test C has a sensitivity of 0.98 and a specificity of 0.93. Which of the following testing schemes should the coordinator pursue?

Test C on the entire student body followed by Test A on those who are positive

Test A on the entire student body followed by Test B on those who are positive

Test A on the entire student body followed by Test C on those who are positive

Test C on the entire student body followed by Test B on those who are positive

Test B on the entire student body followed by Test A on those who are positive

A 28-year-old G1P0 woman at 16 weeks estimated gestational age presents for prenatal care. Routine prenatal screening tests are performed and reveal a positive HIV antibody test. The patient is extremely concerned about the possible transmission of HIV to her baby and wants to have the baby tested as soon as possible after delivery. Which of the following would be the most appropriate diagnostic test to address this patient’s concern?

Polymerase chain reaction (PCR) for HIV RNA

A 12-year-old boy is brought in by his mother to the emergency department. He has had abdominal pain, fever, nausea, vomiting, and loss of appetite since yesterday. At first, the mother believed it was just a "stomach flu," but she is growing concerned about his progressive decline. Vitals include: T 102.3 F, HR 110 bpm, BP 120/89 mmHg, RR 16, O2 Sat 100%. Abdominal exam is notable for pain over the right lower quadrant. What is the next best step in management in addition to IV hydration and analgesia?

Right lower quadrant ultrasound

Upright and supine abdominal radiographs

Abdominal MRI with gadolinium contrast

Abdominal CT scan with IV contrast

Abdominal CT scan with IV and PO contrast

A 10-year-old girl with a rash is brought to the clinic by her mother. The patient’s mother says that the onset of the rash occurred 2 days ago. The rash was itchy, red, and initially localized to the cheeks with circumoral pallor, and it gradually spread to the arms and trunk. The patient’s mother also says her daughter had been reporting a high fever of 39.4°C (102.9°F), headaches, myalgia, and flu-like symptoms about a week ago, which resolved in 2 days with acetaminophen. The patient has no significant past medical history. Her vital signs include: temperature 37.0°C (98.6°F), pulse 90/min, blood pressure 125/85 mm Hg, respiratory rate 20/min. Physical examination shows a symmetric erythematous maculopapular rash on both cheeks with circumoral pallor, which extends to the patient’s trunk, arms, and buttocks. The remainder of the exam is unremarkable. Laboratory findings are significant for a leukocyte count of 7,100/mm3 and platelet count of 325,000/mm3. Which of the following is the next best step in the management of this patient?

Discharge home, saying that the patient may immediately return to school

Administer intravenous immunoglobulin (IVIG)

Discharge home, saying that the patient may return to school after the disappearance of the rash

Discharge home with instructions for strict isolation from pregnant women until disappearance of the rash

A 16-month-old male patient, with no significant past medical history, is brought into the emergency department for the second time in 5 days with tachypnea, expiratory wheezes and hypoxia. The patient presented to the emergency department initially due to rhinorrhea, fever and cough. He was treated with nasal suctioning and discharged home. The mother states that, over the past 5 days, the patient has started breathing faster with chest retractions. His vital signs are significant for a temperature of 100.7 F, respiratory rate of 45 and oxygen saturation of 90%. What is the most appropriate treatment for this patient?

Nasal suctioning, oxygen therapy and IV fluids

Albuterol, ipratropium and IV methylprednisolone

IV cefotaxime and IV vancomycin

Humidified oxygen, racemic epinephrine and intravenous (IV) dexamethasone

Pediatric HIV for USMLE Step 1: High-Yield Pediatrics Lessons

Transmission & PPTCT - The Unwanted Inheritance

Vertical Transmission: Accounts for >90% of pediatric cases.
- In-utero (placental): ~25-35% of transmission.
- Intra-partum (delivery): ~60-70%; highest risk.
- Post-partum (breastfeeding): ~10-15% risk.
Major Risk Factor: High maternal plasma viral load (>1000 copies/mL).

⭐ The majority of mother-to-child HIV transmission occurs during the intra-partum period (delivery).

Diagnosis - Spotting the Stowaway

Antibody Tests (ELISA/Western Blot): Unreliable for diagnosis in infants < 18 months. Transplacental maternal IgG antibodies persist, causing false-positive results. An antibody test at 18 months helps confirm final HIV-negative status.
Virological Assays (Gold Standard): HIV DNA PCR is the definitive method. It detects proviral DNA within the infant's own cells, enabling Early Infant Diagnosis (EID).

⭐ A single positive virological test is insufficient for diagnosis. A confirmatory repeat test on a new blood sample is mandatory to finalize the diagnosis of HIV infection.

Diagnostic Algorithm:

Clinical Features & Staging - The Symptom Medley

WHO Clinical Staging: A progressive spectrum from mild to severe.
- Stage 1: Asymptomatic or Persistent Generalized Lymphadenopathy (PGL).
- Stage 2: Unexplained hepatosplenomegaly, papular pruritic eruptions, recurrent URIs.
  
  ⭐ Painless, bilateral parotid gland enlargement is a highly characteristic early sign.
- Stage 3: Moderate malnutrition, oral hairy leukoplakia, Lymphoid Interstitial Pneumonitis (LIP), pulmonary TB.
- Stage 4 (AIDS-defining): Severe wasting/stunting, Pneumocystis jirovecii pneumonia (PJP), recurrent severe bacterial infections (≥2/year), CMV retinitis.

Pediatric HIV: Bilateral Parotid Swelling

Management & ART - Fighting Back Early

Goals: Suppress viral replication (↓VL), restore immune function (↑CD4), reduce morbidity & mortality.
Initiation (NACO): Treat All! Initiate ART for all children with HIV, regardless of WHO stage or CD4 count.
First-Line ART Regimens:
- < 3 years: Abacavir (ABC) + Lamivudine (3TC) + Lopinavir/r (LPV/r).
- > 3 years: ABC + 3TC + Dolutegravir (DTG).
- > 10 years (>35kg): Tenofovir (TDF) + 3TC + DTG.
Second-Line ART: Guided by resistance testing after first-line failure. Involves switching to a new drug class.
PJP Prophylaxis (Co-trimoxazole):
- Start for ALL HIV-exposed infants at 4-6 weeks of age.
- Continue until HIV infection is reliably excluded.

⭐ All infants born to HIV+ mothers receive ART prophylaxis at birth (e.g., Nevirapine) and MUST start Co-trimoxazole prophylaxis at 6 weeks of age.

High‑Yield Points - ⚡ Biggest Takeaways

Vertical transmission is the most common route of infection in children.

HIV DNA PCR is the diagnostic test of choice for infants <18 months.

CD4 counts are physiologically higher in children; use age-specific percentages for staging.

PJP prophylaxis with Cotrimoxazole is critical, started at 4-6 weeks of age.

Lifelong ART is recommended for all HIV-infected children, irrespective of clinical or immunological stage.

Live vaccines (MMR, Varicella) can be given if the child has a CD4 count >15%.

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Pediatric HIV