Prenatal infection screening (TORCH, HIV, STIs) — MCQs

10 questions

A 40-year-old pregnant woman, G4 P3, visits your office at week 30 of gestation. She is very excited about her pregnancy and wants to be the healthiest she can be in preparation for labor and for her baby. What vaccination should she receive at this visit?

A 27-year-old woman, gravida 2, para 1, at 37 weeks' gestation is admitted to the hospital in active labor. She has received routine prenatal care, but she has not been tested for group B streptococcal (GBS) colonization. Pregnancy and delivery of her first child were complicated by an infection with GBS that resulted in sepsis in the newborn. Current medications include folic acid and a multivitamin. Vital signs are within normal limits. The abdomen is nontender and contractions are felt every 4 minutes. There is clear amniotic fluid pooling in the vagina. The fetus is in a cephalic presentation. The fetal heart rate is 140/min. Which of the following is the most appropriate next step in management?

A 27-year-old woman, gravida 2, para 1, at 36 weeks' gestation comes to the physician for a prenatal visit. She feels well. Fetal movements are adequate. This is her 7th prenatal visit. She had an ultrasound scan performed 1 month ago that showed a live intrauterine pregnancy consistent with a 32-week gestation with no anomalies. She had a Pap smear performed 1 year ago, which was normal. Vital signs are within normal limits. Pelvic examination shows a uterus consistent in size with a 36-week gestation. Her blood group and type is A negative. Which of the following is the most appropriate next step in management?

A 34-year-old woman, gravida 2, para 0, at 28 weeks' gestation comes to the physician for a prenatal visit. She has not had regular prenatal care. Her most recent ultrasound at 20 weeks of gestation confirmed accurate fetal dates and appropriate fetal development. She takes levothyroxine for hypothyroidism. She used to work as a nurse before she emigrated from Brazil 13 years ago. She lost her immunization records during the move and cannot recall all of her vaccinations. She appears well. Vital signs are within normal limits. Physical examination shows a fundal height of 26 cm and no abnormalities. An ELISA test for HIV is negative. Serology testing shows hepatitis B surface antibody positive, hepatitis B core antibody and surface antigen negative, and hepatitis A antibody negative. Hepatitis C antibody is positive with detectable RNA. Given her incomplete vaccination history and current serologic results, which of the following vaccinations is most appropriate to recommend at this time?

A 3175-g (7-lb) female newborn is delivered at 37 weeks to a 26-year-old primigravid woman. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. The pregnancy had been uncomplicated. The mother had no prenatal care. She immigrated to the US from Brazil 2 years ago. Immunization records are not available. One day after delivery, the newborn's temperature is 37.5°C (99.5°F), pulse is 182/min, respirations are 60/min, and blood pressure is 82/60 mm Hg. The lungs are clear to auscultation. Cardiac examination shows a continuous heart murmur. The abdomen is soft and nontender. There are several discolored areas on the skin that are non-blanchable upon pressure application. Slit lamp examination shows cloudy lenses in both eyes. The newborn does not pass her auditory screening tests. Which of the following is the most likely diagnosis?

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 3-day-old female newborn delivered vaginally at 36 weeks to a 27-year-old woman has generalized convulsions lasting 3 minutes. Prior to the event, she was lethargic and had difficulty feeding. The infant has two healthy older siblings and the mother's immunizations are up-to-date. The infant appears icteric. The infant's weight and length are at the 5th percentile, and her head circumference is at the 99th percentile for gestational age. There are several purpura of the skin. Ocular examination shows posterior uveitis. Cranial ultrasonography shows ventricular dilatation, as well as hyperechoic foci within the cortex, basal ganglia, and periventricular region. Which of the following is the most likely diagnosis?

A 27-year-old woman presents to her obstetrician for a regular follow-up appointment. The patient is 32 weeks pregnant. She has been followed throughout her pregnancy and has been compliant with care. The patient has a past medical history of a seizure disorder which is managed with valproic acid as well as anaphylaxis when given IV contrast, penicillin, or soy. During the patient's pregnancy she has discontinued her valproic acid and is currently taking prenatal vitamins, folic acid, iron, and fish oil. At this visit, results are notable for mild anemia, as well as positive findings for an organism on darkfield microscopy. The patient is up to date on her vaccinations and her blood glucose is 117 mg/dL at this visit. Her blood pressure is 145/99 mmHg currently. Which of the following is the most appropriate management for this patient?

A 20-year-old woman with no significant past medical history presents to the urgent care clinic with increased vaginal discharge and dysuria. On social history review, she endorses having multiple recent sexual partners. The patient uses oral contraceptive pills for contraception and states that she has not missed a pill. The patient's blood pressure is 119/80 mm Hg, pulse is 66/min, and respiratory rate is 16/min. On pelvic examination, there are multiple punctate, red petechiae on her cervix. Wet mount demonstrates motile flagellated organisms. Which of the following is the recommended treatment for her underlying diagnosis?

Q10

A 22-year-old student presents to the college health clinic with a 1-week history of fever, sore throat, nausea, and fatigue. He could hardly get out of bed this morning. There are no pets at home. He admits to having recent unprotected sex. The vital signs include: temperature 38.3°C (101.0°F), pulse 72/min, blood pressure 118/63 mm Hg, and respiratory rate 15/min. On physical examination, he has bilateral posterior cervical lymphadenopathy, exudates over the palatine tonsil walls with soft palate petechiae, an erythematous macular rash on the trunk and arms, and mild hepatosplenomegaly. What is the most likely diagnosis?

Prenatal infection screening (TORCH, HIV, STIs) US Medical PG Practice Questions and MCQs

Question 1: A 40-year-old pregnant woman, G4 P3, visits your office at week 30 of gestation. She is very excited about her pregnancy and wants to be the healthiest she can be in preparation for labor and for her baby. What vaccination should she receive at this visit?

A. Measles, mumps, and rubella (MMR)
B. Varicella vaccine
C. Herpes zoster vaccine
D. Live attenuated influenza vaccine
E. Tetanus, diphtheria, and acellular pertussis (Tdap) (Correct Answer)

Explanation: ***Tetanus, diphtheria, and acellular pertussis (Tdap)*** - The Tdap vaccine is recommended during each pregnancy, preferably between **27 and 36 weeks of gestation**, to maximize maternal antibody response and passive antibody transfer to the fetus. - This provides critical protection against **pertussis (whooping cough)** for the newborn, who is too young to be vaccinated. *Measles, mumps, and rubella (MMR)* - The **MMR vaccine is a live vaccine** and is **contraindicated during pregnancy** due to the theoretical risk of congenital rubella syndrome, although no cases have been reported. - It should be administered **postpartum** if the mother is not immune to rubella. *Varicella vaccine* - The **varicella vaccine is a live vaccine** and is **contraindicated during pregnancy** due to the theoretical risk of congenital varicella syndrome. - Like MMR, it should be offered in the **postpartum period** if the woman is not immune. *Herpes zoster vaccine* - The herpes zoster vaccine is typically recommended for **older adults** (50 years and older) for shingles prevention. - It is **not routinely recommended during pregnancy**, and its safety and efficacy in this population have not been sufficiently established. *Live attenuated influenza vaccine* - The **live attenuated influenza vaccine (LAIV)** is **contraindicated during pregnancy** due to its live virus content. - Pregnant women should receive the **inactivated influenza vaccine (IIV)**, which is safe and recommended during any trimester.

Question 2: A 27-year-old woman, gravida 2, para 1, at 37 weeks' gestation is admitted to the hospital in active labor. She has received routine prenatal care, but she has not been tested for group B streptococcal (GBS) colonization. Pregnancy and delivery of her first child were complicated by an infection with GBS that resulted in sepsis in the newborn. Current medications include folic acid and a multivitamin. Vital signs are within normal limits. The abdomen is nontender and contractions are felt every 4 minutes. There is clear amniotic fluid pooling in the vagina. The fetus is in a cephalic presentation. The fetal heart rate is 140/min. Which of the following is the most appropriate next step in management?

A. Obtain vaginal-rectal swab for nucleic acid amplification testing
B. Obtain vaginal-rectal swab for GBS culture
C. Administer intrapartum intravenous penicillin (Correct Answer)
D. Reassurance
E. Obtain vaginal-rectal swab for GBS culture and nucleic acid amplification testing

Explanation: ***Administer intrapartum intravenous penicillin*** - This patient has a **previous infant with invasive GBS disease**, which is a strong indication for **intrapartum antibiotic prophylaxis (IAP)** regardless of current GBS colonization status. - Penicillin is the **first-line agent** for GBS prophylaxis during labor to prevent vertical transmission to the newborn. *Obtain vaginal-rectal swab for nucleic acid amplification testing* - While **NAAT** can provide rapid results, the presence of a prior infant with invasive GBS disease is an **absolute indication** for IAP, making testing unnecessary. - Waiting for NAAT results would **delay necessary antibiotic administration**, increasing the risk of GBS transmission. *Obtain vaginal-rectal swab for GBS culture* - A **GBS culture** typically takes 24-48 hours for results, which is too long given the patient is in active labor and requires immediate management. - As with NAAT, a prior affected infant means that **IAP is indicated regardless of current culture results**. *Reassurance* - Reassurance alone is **insufficient** given the patient's history of a previous infant with GBS sepsis, which places her current fetus at high risk. - **Active intervention** with antibiotics is crucial to prevent recurrence of GBS disease in the newborn. *Obtain vaginal-rectal swab for GBS culture and nucleic acid amplification testing* - Performing both tests is **unnecessary and delays treatment** in a patient with a clear indication for intrapartum antibiotics. - The patient's history of a prior infant with GBS sepsis is classified as a **high-risk factor, necessitating immediate antibiotic prophylaxis** without waiting for test results.

Question 3: A 27-year-old woman, gravida 2, para 1, at 36 weeks' gestation comes to the physician for a prenatal visit. She feels well. Fetal movements are adequate. This is her 7th prenatal visit. She had an ultrasound scan performed 1 month ago that showed a live intrauterine pregnancy consistent with a 32-week gestation with no anomalies. She had a Pap smear performed 1 year ago, which was normal. Vital signs are within normal limits. Pelvic examination shows a uterus consistent in size with a 36-week gestation. Her blood group and type is A negative. Which of the following is the most appropriate next step in management?

A. Transabdominal doppler ultrasonography
B. Rh antibody testing
C. Swab for GBS culture (Correct Answer)
D. Serum PAPP-A and HCG levels
E. Complete blood count

Explanation: ***Swab for GBS culture*** - All pregnant women should be screened for **Group B Streptococcus (GBS)** between **36 weeks 0 days and 37 weeks 6 days** of gestation. - A positive GBS culture requires **intrapartum antibiotic prophylaxis** to prevent early-onset neonatal GBS disease. *Transabdominal doppler ultrasonography* - **Doppler ultrasonography** is primarily used to assess **fetal well-being** in cases of **fetal growth restriction**, preeclampsia, or other high-risk conditions. - This patient has a **normal-sized uterus** and **adequate fetal movements**, indicating no immediate need for fetal Doppler assessment. *Rh antibody testing* - **Rh antibody testing** (indirect Coombs test) is performed early in pregnancy for Rh-negative women and typically repeated at **28 weeks' gestation** before anti-D immune globulin administration. - Repeating this test at 36 weeks is not the most appropriate *next* step as the routine schedule for Rh immune globulin would typically be managed prior to this point. *Serum PAPP-A and HCG levels* - **Serum PAPP-A and HCG levels** are components of **first-trimester screening** for chromosomal abnormalities, performed between 11 and 14 weeks of gestation. - At 36 weeks' gestation, these markers are not relevant for current fetal assessment. *Complete blood count* - A **complete blood count (CBC)** is routinely performed in the first trimester and often repeated in the **late second or early third trimester** (around 28 weeks) to check for anemia. - While a CBC might be done as part of general prenatal care, it is not the most urgent or specifically indicated test at 36 weeks in the absence of symptoms.

Question 4: A 34-year-old woman, gravida 2, para 0, at 28 weeks' gestation comes to the physician for a prenatal visit. She has not had regular prenatal care. Her most recent ultrasound at 20 weeks of gestation confirmed accurate fetal dates and appropriate fetal development. She takes levothyroxine for hypothyroidism. She used to work as a nurse before she emigrated from Brazil 13 years ago. She lost her immunization records during the move and cannot recall all of her vaccinations. She appears well. Vital signs are within normal limits. Physical examination shows a fundal height of 26 cm and no abnormalities. An ELISA test for HIV is negative. Serology testing shows hepatitis B surface antibody positive, hepatitis B core antibody and surface antigen negative, and hepatitis A antibody negative. Hepatitis C antibody is positive with detectable RNA. Given her incomplete vaccination history and current serologic results, which of the following vaccinations is most appropriate to recommend at this time?

A. Undergo liver biopsy
B. Schedule a cesarean delivery
C. Start combination therapy with interferon α and ribavirin
D. Counsel about transmission risks and plan postpartum treatment
E. Hepatitis A vaccination (Correct Answer)

Explanation: ***Hepatitis A vaccination*** - The patient has no prior immunity to **Hepatitis A**, as indicated by the **negative Hepatitis A antibody** serology. - Vaccination against **Hepatitis A** is crucial in this patient, especially given her increased risk of exposure due to being a former healthcare worker and a positive hepatitis C infection. *Undergo liver biopsy* - A **liver biopsy** is an invasive procedure and is generally not recommended during pregnancy, especially when other diagnostic or management strategies are available. - While it can assess the degree of liver damage, it is usually reserved for specific indications and is not the most appropriate immediate step for vaccine recommendation. *Schedule a cesarean delivery* - **Hepatitis C viral transmission** to the fetus is primarily vertical during birth, but a **cesarean delivery** has not been shown to significantly reduce this risk compared to vaginal delivery. - The decision regarding delivery method is typically made based on obstetric indications rather than solely for Hepatitis C prevention. *Start combination therapy with interferon α and ribavirin* - **Interferon α** and **ribavirin** are contraindicated during pregnancy due to their **teratogenic effects** and severe side effects. - Antiviral treatment for Hepatitis C is generally deferred until **postpartum**. *Counsel about transmission risks and plan postpartum treatment* - While counseling about **transmission risks** and planning **postpartum treatment** for Hepatitis C is essential, it addresses the existing Hepatitis C infection rather than prescribing a vaccination, which is the direct question. - It is an important part of comprehensive care for this patient but not the most appropriate *vaccination* recommendation.

Question 5: A 3175-g (7-lb) female newborn is delivered at 37 weeks to a 26-year-old primigravid woman. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. The pregnancy had been uncomplicated. The mother had no prenatal care. She immigrated to the US from Brazil 2 years ago. Immunization records are not available. One day after delivery, the newborn's temperature is 37.5°C (99.5°F), pulse is 182/min, respirations are 60/min, and blood pressure is 82/60 mm Hg. The lungs are clear to auscultation. Cardiac examination shows a continuous heart murmur. The abdomen is soft and nontender. There are several discolored areas on the skin that are non-blanchable upon pressure application. Slit lamp examination shows cloudy lenses in both eyes. The newborn does not pass her auditory screening tests. Which of the following is the most likely diagnosis?

A. Congenital CMV infection
B. Congenital syphilis
C. Congenital parvovirus B19 infection
D. Congenital toxoplasmosis
E. Congenital rubella infection (Correct Answer)

Explanation: ***Congenital rubella infection*** - The constellation of **congenital cataracts** (cloudy lenses), **patent ductus arteriosus** (continuous murmur), **sensorineural hearing loss** (failed auditory screening), and **blueberry muffin rash** (discolored, non-blanchable skin areas) is highly characteristic of congenital rubella syndrome. - The mother's lack of prenatal care and unknown immunization status, coupled with immigration from Brazil where rubella might be more prevalent, increases the likelihood of an unvaccinated mother acquiring the infection during pregnancy. *Congenital CMV infection* - While CMV can cause **sensorineural hearing loss**, it typically presents with **periventricular calcifications** on neuroimaging, **microcephaly**, and often **hepatosplenomegaly** and **thrombocytopenia**, which are not mentioned here. - Although CMV can cause chorioretinitis and cataracts, the classic cardiac and skin findings of rubella are absent. *Congenital syphilis* - Congenital syphilis can present with a wide range of manifestations, including **hepatosplenomegaly**, **snuffles**, **bone lesions** (e.g., periostitis), and a **rash**, but the specific combination of cataracts, patent ductus arteriosus, and blueberry muffin rash is not typical. - Eye involvement in syphilis is usually interstitial keratitis, not cataracts, and cardiac defects are less common or different. *Congenital parvovirus B19 infection* - Parvovirus B19 is primarily associated with **hydrops fetalis**, severe **anemia**, and sometimes myocarditis. - It does not typically cause **cataracts**, **patent ductus arteriosus**, or the characteristic rash seen in this case. *Congenital toxoplasmosis* - Congenital toxoplasmosis classically presents as a triad of **hydrocephalus**, **intracranial calcifications**, and **chorioretinitis**. - It does not typically cause **congenital cataracts**, **patent ductus arteriosus**, or the "blueberry muffin" rash.

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

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.

Question 7: A 3-day-old female newborn delivered vaginally at 36 weeks to a 27-year-old woman has generalized convulsions lasting 3 minutes. Prior to the event, she was lethargic and had difficulty feeding. The infant has two healthy older siblings and the mother's immunizations are up-to-date. The infant appears icteric. The infant's weight and length are at the 5th percentile, and her head circumference is at the 99th percentile for gestational age. There are several purpura of the skin. Ocular examination shows posterior uveitis. Cranial ultrasonography shows ventricular dilatation, as well as hyperechoic foci within the cortex, basal ganglia, and periventricular region. Which of the following is the most likely diagnosis?

A. Congenital parvovirus infection
B. Congenital Toxoplasma gondii infection (Correct Answer)
C. Congenital Treponema pallidum infection
D. Congenital cytomegalovirus infection
E. Congenital rubella infection

Explanation: ***Congenital Toxoplasma gondii infection*** - **Ventricular dilatation** with widespread **hyperechoic foci** (calcifications) in the brain, along with **posterior uveitis**, highly suggests congenital toxoplasmosis. - Other features like **generalized convulsions**, **icterus**, **purpura**, and **microcephaly** (indicated by 5th percentile weight/length vs 99th percentile head circumference discrepancy suggesting hydrocephalus with macrocephaly) are also consistent with this diagnosis. *Congenital parvovirus infection* - Primarily causes severe **anemia**, **hydrops fetalis**, and **myocarditis**; it does not typically present with extensive cerebral calcifications or uveitis. - While it can lead to neurological issues, the specific brain imaging findings and ocular involvement described are not characteristic. *Congenital Treponema pallidum infection* - Characterized by rhinitis (**snuffles**), **hepatosplenomegaly**, **bone abnormalities** (e.g., osteochondritis), and **rash**. - While it can cause CNS involvement and developmental delays, the distinct pattern of brain calcifications and uveitis is not typical. *Congenital cytomegalovirus infection* - Can cause **periventricular calcifications**, but the widespread, diffuse calcifications (cortex, basal ganglia, periventricular) are less typical than with toxoplasmosis, which often shows more diffuse parenchymal calcifications. - While it shares features like small for gestational age, icterus, and purpura, **posterior uveitis** is more strongly associated with toxoplasmosis. *Congenital rubella infection* - Classic triad includes **cataracts** (or glaucoma), **sensorineural hearing loss**, and **congenital heart defects** (e.g., PDA, pulmonary artery stenosis). - While CNS involvement (e.g., intellectual disability, microcephaly) can occur, the widespread cerebral calcifications and posterior uveitis are not characteristic.

Question 8: A 27-year-old woman presents to her obstetrician for a regular follow-up appointment. The patient is 32 weeks pregnant. She has been followed throughout her pregnancy and has been compliant with care. The patient has a past medical history of a seizure disorder which is managed with valproic acid as well as anaphylaxis when given IV contrast, penicillin, or soy. During the patient's pregnancy she has discontinued her valproic acid and is currently taking prenatal vitamins, folic acid, iron, and fish oil. At this visit, results are notable for mild anemia, as well as positive findings for an organism on darkfield microscopy. The patient is up to date on her vaccinations and her blood glucose is 117 mg/dL at this visit. Her blood pressure is 145/99 mmHg currently. Which of the following is the most appropriate management for this patient?

A. Doxycycline
B. Azithromycin and ceftriaxone
C. Insulin, exercise, folic acid, and iron
D. Ceftriaxone
E. Penicillin (Correct Answer)

Explanation: ***Penicillin*** - The positive findings for an organism on **darkfield microscopy** in a pregnant patient strongly suggest **syphilis**, caused by *Treponema pallidum*. - **Penicillin** is the only proven effective treatment for syphilis during pregnancy, as it is the only antibiotic that reliably crosses the placenta to treat the fetus and prevent **congenital syphilis**, despite the patient's penicillin allergy history, which often necessitates desensitization. *Doxycycline* - **Doxycycline** is contraindicated in pregnancy due to its potential to cause **dental staining** and **bone abnormalities** in the fetus. - While effective for syphilis in non-pregnant individuals, it is not used as a first-line treatment during pregnancy. *Azithromycin and ceftriaxone* - This combination is typically used for suspected **gonorrhea** and **chlamydia coinfection**, not syphilis. - While ceftriaxone could be considered in certain syphilis cases, azithromycin is not a primary treatment for syphilis, and penicillin remains superior in pregnancy. *Insulin, exercise, folic acid, and iron* - This option addresses the patient's elevated blood glucose (117 mg/dL, which is suspicious for **gestational diabetes** or impaired glucose tolerance) and anemia, along with routine prenatal supplements, but does not address the **syphilis infection**. - While these are important aspects of prenatal care, they do not manage the acute infectious process identified by darkfield microscopy. *Ceftriaxone* - **Ceftriaxone** is primarily used to treat **gonorrhea** and is an alternative for syphilis in non-pregnant patients with penicillin allergy. - However, in pregnancy, penicillin is still preferred for syphilis due to its efficacy in preventing **congenital syphilis**, making desensitization necessary even with an allergy.

Question 9: A 20-year-old woman with no significant past medical history presents to the urgent care clinic with increased vaginal discharge and dysuria. On social history review, she endorses having multiple recent sexual partners. The patient uses oral contraceptive pills for contraception and states that she has not missed a pill. The patient's blood pressure is 119/80 mm Hg, pulse is 66/min, and respiratory rate is 16/min. On pelvic examination, there are multiple punctate, red petechiae on her cervix. Wet mount demonstrates motile flagellated organisms. Which of the following is the recommended treatment for her underlying diagnosis?

A. Vaginal metronidazole
B. PO fluconazole
C. Vaginal clindamycin
D. Single-dose PO metronidazole (Correct Answer)
E. IM benzathine penicillin

Explanation: ***Single-dose PO metronidazole*** - The symptoms of **increased vaginal discharge**, **dysuria**, and **cervical petechiae** (strawberry cervix) in a sexually active woman, along with motile, flagellated organisms on wet mount, are classic for **Trichomonas vaginalis** infection. - The recommended treatment for trichomoniasis is a single 2-gram oral dose of **metronidazole**, or 500 mg orally twice daily for 7 days. *Vaginal metronidazole* - While metronidazole is the correct drug, the **vaginal formulation** is less effective than oral metronidazole for treating trichomoniasis. - **Oral metronidazole** achieves higher systemic concentrations and treats potential involvement of the **urethra** and **paraurethral glands**, which vaginal formulations may not adequately address. *PO fluconazole* - **Fluconazole** is an antifungal medication primarily used to treat **yeast infections** (candidiasis), not parasitic infections like trichomoniasis. - The clinical presentation and wet mount findings (motile flagellated organisms) are not consistent with a yeast infection. *Vaginal clindamycin* - **Clindamycin** is an antibiotic used to treat **bacterial vaginosis** (BV). - While BV can cause vaginal discharge, the presence of **motile flagellated organisms** and **cervical petechiae** are specific to trichomoniasis, and not typically seen in BV. *IM benzathine penicillin* - **Benzathine penicillin** is the standard treatment for **syphilis**. - The patient's symptoms and wet mount findings are not indicative of syphilis, which presents with chancres, rashes, or neurological symptoms depending on the stage.

Question 10: A 22-year-old student presents to the college health clinic with a 1-week history of fever, sore throat, nausea, and fatigue. He could hardly get out of bed this morning. There are no pets at home. He admits to having recent unprotected sex. The vital signs include: temperature 38.3°C (101.0°F), pulse 72/min, blood pressure 118/63 mm Hg, and respiratory rate 15/min. On physical examination, he has bilateral posterior cervical lymphadenopathy, exudates over the palatine tonsil walls with soft palate petechiae, an erythematous macular rash on the trunk and arms, and mild hepatosplenomegaly. What is the most likely diagnosis?

A. Toxoplasma infection
B. Streptococcal pharyngitis
C. Rubella
D. Acute HIV infection
E. Infectious mononucleosis (Correct Answer)

Explanation: ***Infectious mononucleosis*** - The combination of **fever**, **fatigue**, **sore throat**, **posterior cervical lymphadenopathy**, tonsillar exudates, and **hepatosplenomegaly** in a young adult is highly suggestive of infectious mononucleosis, commonly caused by **Epstein-Barr virus (EBV)**. - The presence of **soft palate petechiae** and a mild, **erythematous rash** (which can occur in EBV mononucleosis, especially if amoxicillin is mistakenly prescribed) further supports this diagnosis. *Toxoplasma infection* - While **Toxoplasma gondii** can cause lymphadenopathy and fatigue, it is less commonly associated with significant **pharyngitis** with exudates and hepatosplenomegaly in immunocompetent individuals. - The recent unprotected sex and specific rash pattern are not typical features for **primary toxoplasmosis** in this context. *Streptococcal pharyngitis* - Classic strep throat presents with **sore throat**, fever, and **tonsillar exudates**, but **marked fatigue**, **hepatosplenomegaly**, and **posterior cervical lymphadenopathy** are unusual. - The widespread erythematous macular rash is not a typical presentation of uncomplicated strep pharyngitis. *Rubella* - **Rubella** typically presents with a **maculopapular rash** that starts on the face and spreads downwards, along with low-grade fever and **postauricular** or **occipital lymphadenopathy**. - **Significant pharyngitis** with exudates and hepatosplenomegaly are not prominent features of rubella. *Acute HIV infection* - **Acute HIV infection** can present with a mononucleosis-like syndrome including fever, fatigue, sore throat, and rash, but **marked exudative tonsillitis** and **hepatosplenomegaly** are less common than in EBV mononucleosis. - While unprotected sex is a risk factor, the specific constellation of findings, particularly the profound fatigue and physical exam findings, point more strongly to infectious mononucleosis.

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