Review Question - QID 214977

This patient was born to a mother who did not receive prenatal care and experienced transient arthralgia with fever in her first trimester concerning for rubella infection. The patient’s presentation of low birth weight, diffuse blueberry muffin macules, bilateral cataracts, and continuous patent ductus arteriosus murmur are consistent with congenital rubella syndrome which is also associated with sensorineural hearing loss.

Congenital rubella syndrome (CRS) is one of the congenital TORCHeS infections (e.g., Toxoplasma gondii, Rubella, Cytomegalovirus (CMV), Human immunodeficiency virus (HIV), Herpes simplex virus (HSV), and syphilis). It is a result of gestational transplacental transmission of the rubella virus, most often during the first trimester. The initial maternal infection is transient and self-resolving, presenting as a mild fever, maculopapular rash, posterior auricular lymphadenopathy, and polyarthralgia. As the first trimester is a critical period for fetal organogenesis and growth, the virus can have devastating effects due to inhibition of cellular mitosis leading to low birth weight, destruction of the ocular lenses (resulting in cataracts), and organ dysgenesis. The viral tropism for vascular endothelium can lead to a patent ductus arteriosus, encephalitis, and sensorineural hearing loss. Prognosis depends on the severity of defects, which are managed supportively; prevention involves prenatal counseling to screen for maternal rubella immune status and vaccination if needed.

Swamy et al. review recommendations for vaccinations for maternal-fetal protection. The authors note that the measles, mumps, and rubella (MMR) vaccine is a live vaccine and is not recommended during pregnancy. However, the authors recommend against abortion if the MMR vaccine is inadvertently administered during pregnancy as large databases have not shown detrimental fetal effects.

Figure/Illustration A shows bilateral white pupils or leukocoria (red arrows), due to cataracts from viral liquefication and necrosis of the lens. Of note, congenital rubella syndrome may also lead to glaucoma and retinopathy.

Figure/Illustration B shows diffuse purple macules, papules, nodules, and petechia representing a classic blueberry muffin rash (black arrows), which is also observed in congenital Toxoplasma gondii and CMV infections. This rash represents multiple skin foci of extramedullary hematopoiesis from underlying dysfunctional bone marrow.

Incorrect Answers:
Answer 1: Hydrocephalus is a classic feature of congenital Toxoplasma gondii infection, due to parasite obstruction of cerebrospinal fluid flow. In contrast, newborns with CRS may have microcephaly.

Answer 2: Intracranial calcifications are a classic radiographic feature of congenital Toxoplasma gondii infection due to parasitic cyst deposition in the brain parenchyma. These calcifications are not observed in CRS.

Answer 3: Notched teeth, also known as Hutchinson teeth, are a classic feature of congenital syphilis infection and are not found in CRS. Other congenital syphilis features include nasal discharge, short maxilla, bowed tibias (i.e., saber shins), and a saddle nose.

Answer 4: Periventricular calcifications are a classic radiographic finding in congenital CMV infection, often accompanied by ventriculomegaly, a feature not observed in CRS.

Bullet Summary:
Congenital rubella syndrome occurs from first trimester transplacental viral transmission with maternal features of transient fever with polyarthralgia and results in newborn characteristics of low birth weight, diffuse blueberry muffin rash, continuous patent ductus arteriosus murmur, and sensorineural hearing loss.