Which of the following is true regarding congenital CMV infection?
Congenital CMV is a big topic. The core concept here is probably about the clinical presentation, transmission, or management. Common facts I remember: CMV is the most common congenital viral infection. It's transmitted from mother to fetus, often during pregnancy. Symptoms can range from asymptomatic to severe issues like microcephaly, hepatosplenomegaly, and sensorineural hearing loss.
The correct answer might relate to the fact that up to 90% of infected infants are asymptomatic at birth but can develop late-onset complications. Or maybe about the diagnostic methods, like detecting CMV in urine or saliva within the first two weeks. Also, treatment options are limited, usually with ganciclovir or valganciclovir in severe cases.
Now, for the wrong options. If the options include things like "most infants show symptoms at birth," that's incorrect because most are asymptomatic. Another wrong option might be about transmission route, like saying it's through breast milk, which is true but not congenital. Or maybe confusing it with other congenital infections like rubella.
Clinical pearl: Remember that congenital CMV is a leading cause of sensorineural hearing loss in children. Also, early detection through PCR testing is crucial for management. High-yield fact: Asymptomatic infants don't need treatment, but those with symptoms might benefit from antiviral therapy, though it's controversial.
Need to structure this into the required sections. Core concept first, then correct answer explanation, then each wrong option, and the clinical pearl. Make sure to keep each section concise and within the character limit. Avoid jargon but use precise terms. Check for accuracy on the latest guidelines, maybe from CDC or AAP.
**Core Concept**
Congenital cytomegalovirus (CMV) infection is the most common congenital viral infection, transmitted from mother to fetus via placenta. It often presents asymptomatically in neonates but can cause sensorineural hearing loss, retinitis, and developmental delays. Diagnosis relies on detection of CMV in urine or saliva within the first 2 weeks of life.
**Why the Correct Answer is Right**
The correct statement is: *"Up to 10% of infected infants exhibit symptoms at birth, but 90% are asymptomatic initially."* This reflects the clinical spectrum of congenital CMV, where most infants appear healthy at birth but risk late-onset complications like hearing loss. Pathophysiology involves viral replication in placental trophoblasts and fetal tissues, leading to inflammation and organ damage. Symptomatic cases present with microcephaly, hepatosplenomegaly, and petechiae.
**Why Each Wrong Option is Incorrect**
**Option A:** *"Congenital CMV is best diagnosed by IgM serology in the newborn."* Incorrect—serology cannot distinguish maternal from fetal antibodies; PCR of urine/saliva is gold standard.
**Option B:** *"All asymptomatic infants require antiviral therapy."* Incorrect—treatment (e.g., ganciclovir) is reserved for