Clinical Scenario:
A term male infant is born to a mother who had an uncomplicated pregnancy. At birth, the infant is noted to have marked microcephaly and increased limb tone. During the first few weeks of life, he develops feeding difficulty and persistent irritability.
Neurological examination shows hypertonia with exaggerated deep tendon reflexes. Ophthalmological examination reveals macular pigmentary mottling. Cranial imaging demonstrates multiple calcifications predominantly at the cortical–subcortical junction, with ventriculomegaly and reduced cerebral volume.
The mother reports that she had a brief episode of rash and conjunctival redness during early pregnancy, which resolved spontaneously.
Which of the following is the most likely diagnosis?
A. Congenital cytomegalovirus infection
B. Congenital toxoplasmosis
C. Congenital Zika virus infection
D. Congenital rubella syndrome
E. Congenital lymphocytic choriomeningitis virus infection
Correct answer & Explanation:
Correct answer: C. Congenital Zika virus infection
Explanation
Congenital Zika virus infection should be strongly suspected when severe microcephaly is accompanied by characteristic brain abnormalities, hypertonia and ocular abnormalities.
A particularly useful imaging clue is the presence of intracranial calcifications at the cortical–subcortical junction, together with reduced brain volume and ventriculomegaly. This pattern differs from the predominantly periventricular calcifications classically associated with congenital CMV infection.
Congenital Zika syndrome can include:
- Severe microcephaly
- Cerebral cortical abnormalities and reduced brain volume
- Intracranial calcifications
- Hypertonia and abnormal limb posture
- Feeding difficulties
- Ocular abnormalities, including macular pigmentary changes
Importantly, maternal Zika infection may be mild or asymptomatic, so the absence of a significant maternal illness does not exclude congenital infection.
Why not congenital CMV? CMV commonly causes microcephaly, intracranial calcifications and neurological impairment, but the cortical–subcortical distribution combined with characteristic macular abnormalities and the maternal clinical history favors congenital Zika infection.
Why not toxoplasmosis? Congenital toxoplasmosis is classically associated with hydrocephalus, intracranial calcifications and chorioretinitis, rather than the characteristic congenital Zika phenotype.
Why not rubella? Congenital rubella more typically produces cataracts, sensorineural hearing loss and congenital heart disease.
Why not lymphocytic choriomeningitis virus? It can cause congenital neurological abnormalities and intracranial calcification, but the overall phenotype here is more consistent with congenital Zika syndrome.
Reference:
Centers for Disease Control and Prevention (CDC). Clinical Signs and Symptoms of Zika Virus Disease.
World Health Organization. Zika virus and complications.
