Pediatric HIV US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Pediatric HIV. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Pediatric HIV US Medical PG Question 1: 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?
- A. Administer lamivudine and nevirapine
- B. Administer zidovudine, lamivudine and nevirapine (Correct Answer)
- C. Administer nevirapine
- D. Administer zidovudine
- E. HIV antibody testing
Pediatric HIV Explanation: ***Administer zidovudine, lamivudine and nevirapine***
- The mother has a **viral load of 678 copies/mL**, which falls into the **intermediate-risk category** (50-999 copies/mL) for HIV transmission.
- Current guidelines recommend **combination antiretroviral prophylaxis** (zidovudine + lamivudine + nevirapine) for infants born to mothers with viral loads in this range, typically given for 2 weeks followed by zidovudine alone to complete 4-6 weeks.
- This enhanced regimen provides better protection than monotherapy when maternal viral suppression is suboptimal.
*Administer zidovudine*
- Zidovudine monotherapy is reserved for **low-risk infants** whose mothers have viral loads **<50 copies/mL** at delivery with documented adherence to ART during pregnancy.
- With a maternal viral load of 678 copies/mL, monotherapy alone is **insufficient** and would not meet current standard of care for HIV prophylaxis.
*Administer lamivudine and nevirapine*
- This regimen omits **zidovudine**, which remains the **backbone of neonatal HIV prophylaxis** and should always be included.
- Using only lamivudine and nevirapine without zidovudine is not consistent with established guidelines.
*Administer nevirapine*
- Nevirapine monotherapy is **not adequate** for HIV prophylaxis in developed countries with access to combination therapy.
- While nevirapine may be used as a single dose in resource-limited settings, it should be part of a multi-drug regimen when other agents are available.
*HIV antibody testing*
- HIV antibody testing in newborns will detect **maternal antibodies** that crossed the placenta and cannot determine the infant's true infection status at birth.
- While HIV diagnostic testing using **PCR or viral load assays** will be performed at 14-21 days, 1-2 months, and 4-6 months of age, **antiretroviral prophylaxis must be initiated immediately** after birth to prevent transmission.
Pediatric HIV US Medical PG Question 2: 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?
- A. Azithromycin and fluconazole
- B. Azithromycin, dapsone, and fluconazole
- C. Dapsone
- D. Fluconazole
- E. Azithromycin and trimethoprim-sulfamethoxazole (Correct Answer)
Pediatric HIV Explanation: ***Azithromycin and trimethoprim-sulfamethoxazole***
- With a **CD4+ count of 33 cells/mm3**, this patient is at high risk for **Pneumocystis jirovecii pneumonia (PJP)** and **Toxoplasma gondii encephalitis**, for which **trimethoprim-sulfamethoxazole (TMP-SMX)** is the prophylaxis of choice.
- He is also at very high risk for **Mycobacterium avium complex (MAC) infection**, for which **azithromycin** is the recommended preventative treatment when the CD4 count is below 50 cells/mm3.
*Azithromycin and fluconazole*
- While **azithromycin** is indicated for MAC prophylaxis, **fluconazole** is typically used for **cryptococcal meningitis** or **candidiasis**, which are not the primary, immediate prophylactic concerns at this specific CD4 count unless there's evidence of these infections.
- The most critical opportunistic infections to prevent at a CD4 count of 33 cells/mm3 are PJP, Toxoplasmosis, and MAC.
*Azithromycin, dapsone, and fluconazole*
- **Dapsone** can be used as an alternative for **PJP prophylaxis** if TMP-SMX is contraindicated, but it is not the first-line choice and does not cover toxoplasmosis as effectively as TMP-SMX alone.
- **Fluconazole** again is not a primary prophylactic agent at this CD4 count in the absence of specific indications.
*Dapsone*
- **Dapsone** is an alternative for **PJP prophylaxis** and can also prevent **Toxoplasma gondii encephalitis** when combined with pyrimethamine, but it is not the first-line recommendation.
- It does not provide coverage against **MAC infection**, which is a significant risk at this CD4 count.
*Fluconazole*
- **Fluconazole** is primarily used for **fungal infections** like **candidiasis** or **cryptococcosis**.
- It does not prevent **PJP, Toxoplasmosis, or MAC**, which are the most critical prophylactic concerns for a patient with a CD4 count of 33 cells/mm3.
Pediatric HIV US Medical PG Question 3: 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?
- A. HAART (Correct Answer)
- B. Breastfeeding
- C. Vaginal delivery
- D. HAART after delivery
- E. Avoidance of antibiotic prophylaxis
Pediatric HIV Explanation: ***HAART***
- **Highly active antiretroviral therapy (HAART)** is recommended immediately for pregnant women with HIV, regardless of CD4 count or viral load, to reduce maternofetal transmission.
- Starting HAART early in pregnancy significantly lowers the **viral load**, protecting the fetus from HIV infection.
*Breastfeeding*
- **Breastfeeding** is contraindicated in HIV-positive mothers in developed countries because it carries a risk of HIV transmission to the infant.
- Formula feeding is recommended to prevent **postnatal HIV transmission**.
*Vaginal delivery*
- A **vaginal delivery** may be considered if the viral load is undetectable or very low (<1,000 copies/mL) at the time of delivery.
- Given this patient's **high viral load** (126,000 copies/mL), a scheduled cesarean section would be indicated to minimize the risk of perinatal transmission.
*HAART after delivery*
- Delaying **HAART until after delivery** would increase the risk of maternofetal HIV transmission during pregnancy and delivery.
- Prompt initiation of HAART is crucial for both maternal health and **fetal protection**.
*Avoidance of antibiotic prophylaxis*
- **Antibiotic prophylaxis** is commonly used in combination with antiretroviral agents to prevent opportunistic infections, especially when the **CD4 count is low** (<200 cells/mm³).
- Given a CD4 count of 150 cells/mm³, prophylaxis against opportunistic infections like **Pneumocystis jirovecii pneumonia** might be indicated, making avoidance inappropriate.
Pediatric HIV US Medical PG Question 4: 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?
- A. Grossly reduced levels of B cells
- B. An X-linked inheritance of HLA genes
- C. Selective IgA deficiency
- D. Defective T cell function (Correct Answer)
- E. Defective isotype switching
Pediatric HIV Explanation: ***Defective T cell function***
- The presentation with recurrent infections (oral candidiasis, RSV pneumonia), persistent diarrhea, and **failure to thrive (lean, 10th percentile weight)** in a young infant, despite negative HIV PCR, strongly suggests a **severe combined immunodeficiency (SCID)**.
- **T-cell dysfunction is the hallmark of SCID**, leading to a broad susceptibility to opportunistic pathogens and impaired immune responses.
*Grossly reduced levels of B cells*
- While some immunodeficiencies involve B-cell defects (e.g., **X-linked agammaglobulinemia**), the primary clinical picture here (severe viral and fungal infections, failure to thrive) points more strongly to a profound T-cell defect affecting both humoral and cellular immunity.
- Reduced B cells alone would primarily result in recurrent bacterial infections rather than the observed opportunistic infections.
*An X-linked inheritance of HLA genes*
- **HLA genes (Major Histocompatibility Complex)** are located on **chromosome 6**, not the X chromosome, and are crucial for antigen presentation, not typically associated with X-linked inheritance patterns.
- Defects in HLA (e.g., bare lymphocyte syndrome) can impair T-cell function but are not solely X-linked and would still fall under the umbrella of defective T-cell function.
*Selective IgA deficiency*
- Patients with selective IgA deficiency are often **asymptomatic** or experience **recurrent sinopulmonary and gastrointestinal infections** but typically do not present with severe opportunistic infections like RSV pneumonia and persistent candidiasis with failure to thrive.
- **T-cell function is preserved** in selective IgA deficiency, making the severe presentation less likely.
*Defective isotype switching*
- This primarily affects the ability of B cells to produce different classes of antibodies **(IgG, IgA, IgE)**, often due to defects in T follicular helper cells or B cell intrinsic defects.
- While it can lead to recurrent infections, particularly bacterial, it does not typically cause the severe, opportunistic infections and failure to thrive seen with primary T-cell defects like SCID.
Pediatric HIV US Medical PG Question 5: 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?
- A. Test A on the entire student body followed by Test B on those who are positive
- B. Test A on the entire student body followed by Test C on those who are positive
- C. Test C on the entire student body followed by Test B on those who are positive
- D. Test C on the entire student body followed by Test A on those who are positive (Correct Answer)
- E. Test B on the entire student body followed by Test A on those who are positive
Pediatric HIV Explanation: ***Test C on the entire student body followed by Test A on those who are positive***
- To "capture as many correct HIV diagnoses as possible" (maximize true positives), the initial screening test should have the **highest sensitivity**. Test C has the highest sensitivity (0.98).
- To "capture as few false positives as possible" (maximize true negatives and confirm diagnoses), the confirmatory test should have the **highest specificity**. Test A has the highest specificity (0.99).
*Test A on the entire student body followed by Test B on those who are positive*
- Starting with Test A (sensitivity 0.92) would miss more true positive cases than starting with Test C (sensitivity 0.98), failing the goal of **capturing as many cases as possible**.
- Following with Test B (specificity 0.96) would result in more false positives than following with Test A (specificity 0.99).
*Test A on the entire student body followed by Test C on those who are positive*
- This scheme would miss many true positive cases initially due to Test A's lower sensitivity compared to Test C.
- Following with Test C would introduce more false positives than necessary, as it has a lower specificity (0.93) than Test A (0.99).
*Test C on the entire student body followed by Test B on those who are positive*
- While Test C is a good initial screen for its high sensitivity, following it with Test B (specificity 0.96) is less optimal than Test A (specificity 0.99) for minimizing false positives in the confirmation step.
- This combination would therefore yield more false positives in the confirmatory stage than using Test A.
*Test B on the entire student body followed by Test A on those who are positive*
- Test B has a sensitivity of 0.95, which is lower than Test C's sensitivity of 0.98, meaning it would miss more true positive cases at the initial screening stage.
- While Test A provides excellent specificity for confirmation, the initial screening step is suboptimal for the goal of capturing as many diagnoses as possible.
Pediatric HIV US Medical PG Question 6: 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?
- A. CD4+ T cell count
- B. Viral culture
- C. Polymerase chain reaction (PCR) for HIV RNA (Correct Answer)
- D. Antigen assay for p24
- E. EIA for HIV antibody
Pediatric HIV Explanation: ***Polymerase chain reaction (PCR) for HIV RNA***
- **PCR for HIV RNA** directly detects the viral genetic material, providing a definitive diagnosis of HIV infection in an infant.
- Unlike antibody tests, PCR can distinguish between passively acquired maternal antibodies and actual infant infection, making it suitable for newborns.
*CD4+ T cell count*
- **CD4+ T cell count** is used to monitor the progression of HIV infection and immunosuppression, not for initial diagnosis, especially in neonates.
- While it's an important marker for HIV disease, it does not confirm the presence of the virus itself in a newborn.
*Viral culture*
- **Viral culture** is a highly specific method for detecting HIV, but it is expensive, time-consuming, and technically demanding.
- It is not routinely used for rapid early diagnosis in neonates due to its practical limitations and the availability of faster, reliable alternatives like PCR.
*Antigen assay for p24*
- The **p24 antigen test** can detect early HIV infection in adults, but its sensitivity is lower in neonates compared to PCR, especially immediately after birth.
- It may not reliably detect infection in newborns due to low viral loads or the presence of maternal antibodies that complex the antigen.
*EIA for HIV antibody*
- An **EIA for HIV antibody** will detect maternal antibodies that have crossed the placenta, meaning it will be positive in nearly all infants born to HIV-positive mothers, regardless of the infant's infection status.
- This test cannot distinguish between passive maternal antibody transfer and true infant infection.
Pediatric HIV US Medical PG Question 7: A 27-year-old woman consults an obstetrician as she is planning to become pregnant. She has been diagnosed with HIV (human immunodeficiency virus) infection recently and is currently taking antiretroviral therapy (HAART), as prescribed by her physician. The obstetrician emphasizes the importance of antenatal and peripartum antiretroviral therapy for reducing the risk of mother-to-child transmission of HIV. She also tells the patient that certain antiretroviral drugs, if taken during pregnancy, increase the risk of birth defects in the fetus. She gives a printed list of such drugs to the woman for educational and informational purposes. Which of the following drugs are most likely to be present on the list?
- A. Nelfinavir and Saquinavir
- B. Abacavir and Didanosine
- C. Efavirenz and Delavirdine (Correct Answer)
- D. Lopinavir and Ritonavir
- E. Lamivudine and Nevirapine
Pediatric HIV Explanation: ***Efavirenz and Delavirdine***
- Both **efavirenz** and **delavirdine** are **non-nucleoside reverse transcriptase inhibitors (NNRTIs)** and have been associated with an increased risk of **teratogenicity**, particularly neural tube defects, in early pregnancy.
- Due to these potential risks, they are generally **avoided during the first trimester of pregnancy** or when pregnancy is being planned, unless no other suitable alternative exists.
*Nelfinavir and Saquinavir*
- **Nelfinavir** and **saquinavir** are **protease inhibitors (PIs)** which are generally considered **safe for use during pregnancy** and are often part of recommended regimens for HIV-positive pregnant women.
- They do not carry the same significant teratogenic risks as some other antiretroviral drugs.
*Abacavir and Didanosine*
- **Abacavir** and **didanosine** are **nucleoside reverse transcriptase inhibitors (NRTIs)** commonly used in HIV treatment.
- While didanosine can be associated with lactic acidosis and pancreatitis, neither drug is typically considered to significantly increase the risk of birth defects.
*Lopinavir and Ritonavir*
- **Lopinavir/ritonavir** is a commonly used **protease inhibitor (PI)** combination that is generally considered **safe and effective for use throughout pregnancy** to prevent mother-to-child transmission.
- It does not have known significant teratogenic effects.
*Lamivudine and Nevirapine*
- **Lamivudine** is an **NRTI** and **nevirapine** is an **NNRTI**. Lamivudine is generally considered safe during pregnancy.
- Nevirapine is used in pregnancy, particularly if started after the first trimester, and generally has a more favorable safety profile regarding birth defects compared to efavirenz and delavirdine.
Pediatric HIV US Medical PG Question 8: 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?
- A. Upright and supine abdominal radiographs
- B. Abdominal MRI with gadolinium contrast
- C. Abdominal CT scan with IV contrast
- D. Right lower quadrant ultrasound (Correct Answer)
- E. Abdominal CT scan with IV and PO contrast
Pediatric HIV Explanation: ***Right lower quadrant ultrasound***
- In a 12-year-old boy with suspected **appendicitis**, **ultrasound** is the preferred initial imaging modality due to its **lack of radiation** and high diagnostic accuracy in this population.
- It effectively identifies an inflamed **appendix**, periappendiceal fluid, and other relevant findings while avoiding radiation exposure, which is particularly important in children.
*Upright and supine abdominal radiographs*
- **Plain abdominal X-rays** are generally not useful for diagnosing appendicitis as they often do not visualize the appendix directly.
- While they can rule out other causes of abdominal pain like **bowel obstruction** or **perforation** (free air), they lack the sensitivity and specificity for appendicitis.
*Abdominal MRI with gadolinium contrast*
- **MRI** is an excellent alternative to CT, especially in pregnant patients, but it is **less readily available** and consumes more time than ultrasound in an emergent setting for a pediatric patient.
- Though it provides good soft tissue detail without radiation, its **cost and accessibility** make it less practical as a first-line imaging test for suspected appendicitis in children.
*Abdominal CT scan with IV contrast*
- An **abdominal CT scan with IV contrast** is highly accurate for diagnosing appendicitis, but it involves significant **ionizing radiation**, which should be minimized in pediatric patients.
- It is typically reserved for cases where ultrasound findings are equivocal or other diagnoses are strongly suspected, or when the patient is older or body habitus limits ultrasound utility.
*Abdominal CT scan with IV and PO contrast*
- Adding **oral contrast** to a CT scan significantly increases the time before imaging can be performed, which is not ideal in an acute emergency like suspected appendicitis.
- While it can help delineate bowel loops, the additional contrast and associated delay are usually **unnecessary** for diagnosing appendicitis and further expose the child to radiation.
Pediatric HIV US Medical PG Question 9: 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?
- A. Administer intravenous immunoglobulin (IVIG)
- B. Discharge home, saying that the patient may return to school after the disappearance of the rash
- C. Transfuse with whole blood
- D. Discharge home with instructions for strict isolation from pregnant women until disappearance of the rash
- E. Discharge home, saying that the patient may immediately return to school (Correct Answer)
Pediatric HIV Explanation: ***Discharge home, saying that the patient may immediately return to school***
- This patient likely has **Fifth Disease (Erythema Infectiosum)**, caused by **Parvovirus B19**, characterized by a **"slapped cheek" rash** and a **lacy, reticular rash** on the trunk and extremities.
- Patients with Fifth Disease are **contagious before the rash appears** and are generally **no longer contagious once the rash develops**, making immediate return to school safe.
*Administer intravenous immunoglobulin (IVIG)*
- **IVIG** is typically reserved for **severe cases of Parvovirus B19 infection** in immunocompromised individuals or those with chronic hemolytic anemias who develop **aplastic crisis**.
- The patient's symptoms are mild and self-limiting, without evidence of severe complications like aplastic anemia (normal leukocyte and platelet counts).
*Discharge home, saying that the patient may return to school after the disappearance of the rash*
- This advice is incorrect because the patient is **no longer contagious once the rash erupts**.
- Requiring isolation until the rash disappears would be unnecessarily disruptive and is not medically indicated for Fifth Disease.
*Transfuse with whole blood*
- **Whole blood transfusion** is not indicated for uncomplicated Fifth Disease, as it can cause significant complications.
- Transfusions are considered only in cases of **severe aplastic crisis** with significant anemia, which is not present in this patient (normal complete blood count).
*Discharge home with instructions for strict isolation from pregnant women until disappearance of the rash*
- While exposure to **Parvovirus B19 in pregnant women** can lead to significant fetal complications (e.g., hydrops fetalis), the patient is **no longer infectious once the rash appears**.
- Therefore, strict isolation from pregnant women **after rash onset** is not necessary, as the risk of transmission has passed.
Pediatric HIV US Medical PG Question 10: 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?
- A. Albuterol, ipratropium and IV methylprednisolone
- B. IV cefotaxime and IV vancomycin
- C. Intubation and IV cefuroxime
- D. Humidified oxygen, racemic epinephrine and intravenous (IV) dexamethasone
- E. Nasal suctioning, oxygen therapy and IV fluids (Correct Answer)
Pediatric HIV Explanation: ***Nasal suctioning, oxygen therapy and IV fluids***
- This patient's presentation with rhinorrhea, fever, cough, tachypnea, expiratory wheezes, and hypoxia, particularly a 16-month-old, strongly suggests **bronchiolitis**, likely caused by **RSV**.
- Management of bronchiolitis is primarily **supportive care**, including maintaining airway patency via nasal suctioning, providing oxygen for hypoxia, and ensuring adequate hydration with IV fluids.
*Albuterol, ipratropium and IV methylprednisolone*
- **Bronchodilators** like albuterol and ipratropium are generally **not recommended** for routine management of bronchiolitis due to lack of consistent efficacy in infants.
- **Corticosteroids** (e.g., methylprednisolone) are also **not routinely indicated** for bronchiolitis and have not been shown to improve outcomes.
*IV cefotaxime and IV vancomycin*
- These are **broad-spectrum antibiotics** used to treat **bacterial infections**, such as severe pneumonia or sepsis.
- The clinical presentation is more consistent with a **viral respiratory infection** (bronchiolitis), and there is no evidence of a bacterial co-infection or sepsis.
*Intubation and IV cefuroxime*
- **Intubation** is an invasive procedure reserved for patients with impending respiratory failure and is not indicated at this stage given the current oxygen saturation of 90% with supportive measures.
- **Cefuroxime** is an antibiotic, and like other antibiotics, is not indicated for a viral illness like bronchiolitis.
*Humidified oxygen, racemic epinephrine and intravenous (IV) dexamethasone*
- **Racemic epinephrine** may be considered for severe bronchiolitis with significant bronchospasm, but its use is not routine and its efficacy is debated.
- **IV dexamethasone** is a corticosteroid, which is not recommended for routine bronchiolitis management. Humidified oxygen is helpful, but the overall regimen is not standard for bronchiolitis.
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