A 4-month-old girl is brought to the emergency department via ambulance after a seizure at home. The patient was born at 35 weeks gestation via spontaneous vaginal delivery to a gravida 3 para 3 woman. The pregnancy was complicated by limited prenatal care and polysubstance use disorder. The patient is currently cared for by a foster family. The foster mother says that she was bottle feeding when the patient's extremities suddenly started shaking. She was unresponsive for 1-2 minutes. On examination, the patient is sleeping but arouses with examination. Height and weight are at the 25th percentile, and head circumference is at the 97th percentile for age. Retinal examination reveals evidence of acute and chronic retinal inflammation and is shown in the image below:
Show Explanatory Sources
Heart and lung sounds are normal. The abdomen is soft with moderate hepatosplenomegaly. Which of the following is the most likely cause of this patient's presentation?
Congenital toxoplasmosis | |
Maternal |
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This infant with seizures and hepatosplenomegaly has chorioretinitis, or inflammation and scarring of the retina and choroid, on funduscopic examination. Chorioretinitis is commonly associated with congenital infections and is a long-term sequela of chronic infection that can lead to permanent vision loss.
The predominant pathogens associated with chorioretinitis include Toxoplasma gondii (most common) and cytomegalovirus (CMV), both of which cause intrauterine infection due to transplacental transmission from an infected mother. Hepatosplenomegaly due to reticuloendothelial activation from chronic infection is a nonspecific finding that can also occur with either pathogen, and other late manifestations can include seizures and intellectual disability. Although both T gondii and CMV are associated with microcephaly, congenital toxoplasmosis can also cause macrocephaly (eg, head circumference at 97th percentile in this patient) due to severe hydrocephalus; this makes Toxoplasma the most likely cause of this patient's presentation.
Diagnosis is confirmed by serology (ie, Toxoplasma IgA or IgM) or PCR testing. Treatment of congenital toxoplasmosis is with pyrimethamine, sulfadiazine, and folinic acid—a multidrug regimen that reduces the parasite burden in the CNS and helps to prevent progression of retinal disease.
(Choice A) Child abuse should be suspected in any infant with retinal hemorrhages, which are seen as areas of blood extravasation on retinal examination, and seizure may occur due to intracranial bleeding. However, this patient's retinal findings are not consistent with hemorrhage.
(Choice B) Seizure may be the initial presentation of an intracranial tumor in a child, and hepatosplenomegaly may also occur. Funduscopic examination may reveal optic disc edema due to increased intracranial pressure; retinal scarring would not be present.
(Choice D) Infants born to mothers with substance abuse disorders during pregnancy are at risk for neonatal abstinence syndrome, which presents in the first week of life with irritability, poor feeding, sneezing, diarrhea, and in severe cases, seizures. Symptoms can last up to a month in rare cases but would not be present or develop at age 4 months. In addition, hepatosplenomegaly and retinitis are not features of this condition.
(Choice E) Niemann-Pick disease is a lipid storage disorder associated with hepatosplenomegaly and neurodegeneration in infancy. Seizures may occur, but retinal findings include a cherry-red macula, not retinal inflammation and scarring.
Educational objective:
Chorioretinitis, or inflammation and scarring of the retina and choroid, is typically caused by chronic infection (eg, Toxoplasma gondii, cytomegalovirus). Congenital toxoplasmosis is the most common etiology, and additional findings include macrocephaly (due to hydrocephalus), hepatosplenomegaly, and seizures.