Symptomatic neonatal CNS involvement is most commonly seen in which group of congenital intrauterine infection –
First, I need to recall the common congenital infections that affect the CNS in neonates. The classic ones are TORCH: Toxoplasma, Other (like syphilis, varicella), Rubella, Cytomegalovirus (CMV), and Herpes. Among these, CMV is the most common cause of congenital infection leading to CNS issues like microcephaly, intracerebral calcifications, and hearing loss.
So the question is asking which group is most associated with symptomatic CNS involvement. If the options are TORCH, then CMV would be the answer. But the user's correct answer is option C. Let me check standard MCQs. For example, in many cases, the options might be listed as TORCH, and CMV is typically the correct one. But without the actual options, I have to assume. Let me proceed with the explanation based on that.
The core concept here is that CMV is the leading cause of symptomatic CNS involvement in congenital infections. It's important because it's the most common, even though other TORCH agents can cause it too. The mechanism involves the virus crossing the placenta, leading to direct damage to the developing brain, especially in the periventricular regions.
For the wrong options, maybe the other TORCH agents are listed. For example, Toxoplasma can cause hydrocephalus, but it's less common. Rubella might lead to deafness and cataracts. Herpes can cause encephalitis but is rare. Syphilis might present with CNS involvement but again, not the most common.
The clinical pearl here is that CMV is the most common cause, so students should remember that. Also, the classic triad of microcephaly, intracranial calcifications, and sensorineural hearing loss points to CMV.
Putting it all together, the explanation should highlight CMV's role, why it's the most common, and differentiate from other TORCH agents. The user needs to know that even though other options can cause CNS issues, CMV is the most frequent. So the correct answer is likely option C, assuming the options are ordered with CMV as C.
**Core Concept**
Congenital infections in neonates can lead to central nervous system (CNS) complications, with **cytomegalovirus (CMV)** being the most common cause of symptomatic CNS involvement. This is due to its high prevalence in pregnant women and direct viral cytopathic effects on neural progenitor cells in the developing brain.
**Why the Correct Answer is Right**
CMV is the leading cause of congenital infection worldwide, with approximately 50% of infected infants showing CNS abnormalities such as microcephaly, intracerebral calcifications, and sensorineural hearing loss. The virus crosses the placenta, replicates in the fetal brain, and causes necrosis of periventricular regions, leading to gliosis and developmental delays. Early diagnosis via PCR or viral culture is critical, as antiviral therapy (e.g., ganc