Review Question - QID 221250

This infant with a purpuric rash, chorioretinitis, signs of hydrocephalus, and diffuse intracranial calcifications most likely has congenital toxoplasmosis infection.

Toxoplasmosis is a classic "TORCH" infection that is transmitted via the consumption of undercooked meat, ingestion of contaminated cat feces, or consumption of unpasteurized goat’s milk. Maternal toxoplasmosis infection is usually asymptomatic but may present with generalized symptoms such as low-grade fever and lymphadenopathy. Primary transplacental transmission occurs when the mother is infected, usually after the first trimester. Infants with congenital toxoplasmosis classically present with the triad of chorioretinitis, intracranial calcifications, and hydrocephalus. Signs of hydrocephalus include lethargy, vomiting, seizures, enlarged head circumference, and ventriculomegaly. Jaundice, sensorineural hearing loss, low birth weight, hepatosplenomegaly, and a “blueberry muffin rash” may also be seen. Treatment includes pyrimethamine and sulfadiazine, along with folinic acid to prevent bone marrow suppression.

Fortin et al. review the evidence regarding outcomes in children born with congenital or perinatal infections. They discuss how, even in the absence of symptoms at birth, children exposed to many infections in utero may be at greater risk for developing neurodevelopmental disorders in childhood. They recommend that congenital infections should be considered in the differential diagnosis of a child with neurodevelopmental challenges.

Figure/Illustration A is a depiction of a retinal exam demonstrating macular lesions (blue circle) consistent with chorioretinitis. This finding is classically seen in patients with congenital toxoplasmosis infection.

Incorrect Answers:
Answer 1: Congenital cytomegalovirus infection would similarly present with seizures, sensorineural deafness, jaundice, chorioretinitis, a purpuric rash, and low birth weight; however, imaging classically shows periventricular calcifications and microcephaly.

Answer 2: Congenital rubella infection would also present with low birth weight, a purpuric rash, chorioretinitis, and hydrocephalus; however, other key distinguishing features of congenital rubella infection are lacking, such as cardiac defects and cataracts. This infant’s mother is up-to-date on immunizations, making an intrauterine rubella infection unlikely.

Answer 3: Congenital syphilis infection may present similarly with premature delivery, low birth weight, jaundice, seizures, and chorioretinitis; however, this patient lacks other characteristic findings of congenital syphilis such as facial abnormalities, including saddle nose and notched teeth, and skeletal deformities such as saber shins.

Answer 5: Congenital varicella infection may also present with low birth weight, chorioretinitis, and seizures, but is less likely in this infant born to a mother with up-to-date immunizations.

Bullet Summary:
Congenital toxoplasmosis presents with the triad of chorioretinitis, hydrocephalus, and intracranial calcifications along with sensorineural deafness, jaundice, and a “blueberry muffin rash.”