A 33-year-old woman, gravida 1 para 0, at 27 weeks gestation comes to the office for a prenatal visit. She had an ultrasound at 8 weeks gestation for pregnancy confirmation but has had no other prenatal care. Several weeks ago, the patient had a fever and a diffuse, nonpruritic, maculopapular rash that lasted 2 days and resolved without intervention. She has no chronic medical conditions. Vital signs are normal. Fundal height is 23 cm. Fetal heart rate is 160/min. Fetal ultrasound reveals bilateral ventriculomegaly and multiple intracranial calcifications within the basal ganglia and at the gray-white matter junction. Fetal ascites and hepatosplenomegaly are noted. Estimated fetal weight is below the 5th percentile for gestational age. This patient's presentation is most likely due to fetal infection from which of the following pathogens?

Question

A 33-year-old woman, gravida 1 para 0, at 27 weeks gestation comes to the office for a prenatal visit.  She had an ultrasound at 8 weeks gestation for pregnancy confirmation but has had no other prenatal care.  Several weeks ago, the patient had a fever and a diffuse, nonpruritic, maculopapular rash that lasted 2 days and resolved without intervention.  She has no chronic medical conditions.  Vital signs are normal.  Fundal height is 23 cm.  Fetal heart rate is 160/min.  Fetal ultrasound reveals bilateral ventriculomegaly and multiple intracranial calcifications within the basal ganglia and at the gray-white matter junction.  Fetal ascites and hepatosplenomegaly are noted.  Estimated fetal weight is below the 5th percentile for gestational age.  This patient's presentation is most likely due to fetal infection from which of the following pathogens?

Quizplus · Accepted Answer

11ec25c8_da8c_a584_bc81_15a3d400d624_MD0003_00 This patient's ultrasound findings are suggestive of congenital toxoplasmosis. Maternal Toxoplasma gondii infection can occur via consumption of undercooked, contaminated meat or through contact with the feces of an infected cat, which is the definitive host of the protozoan oocysts. Although often asymptomatic, adults can have fever, lymphadenopathy, myalgias, and/or a diffuse, nonpruritic, maculopapular rash that resolves spontaneously, as seen in this patient. Although maternal infection is mild, transplacental (vertical) transmission can result in devastating fetal infection. T gondii preferentially destroys fetal neural tissue, which results in ultrasound findings of bilateral ventriculomegaly (ie, hydrocephalus) and diffuse parenchymal intracranial calcifications, particularly within the basal ganglia. Additional fetal findings associated with congenital toxoplasmosis are nonspecific and may include ascites, hepatosplenomegaly, and fetal growth restriction (weight <10th percentile). Patients should undergo amniocentesis for T gondii PCR testing of amniotic fluid to confirm the diagnosis. Prenatal antitoxoplasmal therapy (eg, pyrimethamine, sulfadiazine, folinic acid) may decrease the risk of neurologic sequelae such as chorioretinitis, seizures, and intellectual disability. (Choice A) Herpes simplex virus can be vertically transmitted, but mothers typically have painful genital ulcers rather than a diffuse rash. In addition, common ultrasound findings include calcifications of the placenta and umbilical cord, not the brain parenchyma. (Choice B) Maternal infection with Listeria monocytogenes typically presents with a febrile gastroenteritis. Vertical transmission usually causes sepsis in the neonatal period due to exposure during delivery, but transplacental transmission can occur, typically causing disseminated abscesses, not intracranial calcifications. (Choice C) Parvovirus B19 can cause mild illness with a diffuse rash in adults, and ascites due to fetal hydrops may occur. However, other abnormal fluid collections (eg, pericardial/pleural effusion) are typical, and intracranial calcifications are not associated with this condition. (Choice E) Vertical transmission of varicella-zoster virus results in congenital varicella syndrome, which can cause growth restriction but typically presents with limb abnormalities (eg, bone/muscle hypoplasia). Although cortical atrophy can occur, intracranial calcifications are not seen. Educational objective: Vertical transmission of maternal infection with Toxoplasma gondii can result in fetal infection with characteristic fetal ultrasound findings of hydrocephalus and intracranial calcifications, particularly in the basal ganglia. Nonspecific findings of hepatosplenomegaly and fetal growth restriction are also common. References: Prenatal brain imaging in congenital toxoplasmosis. (http://www.ncbi.nlm.nih.gov/pubmed/21706510) Congenital toxoplasmosis: clinical features, outcomes, treatment, and prevention. (http://www.ncbi.nlm.nih.gov/pubmed/27722099)

A 33-Year-Old Woman, Gravida 1 Para 0, at 27 Weeks