Step by Step
To
Toxoplasma
Congenital toxoplasmosis causes chorioretinitis, hydrocephalus, and intracranial calcifications.
O
Other — syphilis, Zika, and parvovirus B19
Congenital syphilis causes saddle nose deformity, Hutchinson's teeth, and interstitial keratitis. Zika causes microcephaly. Parvovirus B19 can cause hydrops fetalis.
R
Rubella
Congenital rubella syndrome produces a "blueberry muffin" rash, cataracts, deafness, and PDA (patent ductus arteriosus) — a cardiac defect.
C
CMV — the most common congenital infection
Cytomegalovirus is the single most common congenital infection overall, causing periventricular calcifications and sensorineural hearing loss.
H
Herpes and HIV
Active genital herpes lesions at the time of delivery are an indication for C-section, specifically to avoid transmission during vaginal delivery.
A newborn is found to have periventricular calcifications on head imaging along with sensorineural hearing loss — this pattern points to CMV, the single most common congenital infection overall, distinguishing it from Toxoplasma's more diffuse intracranial calcification pattern.
Applied Walkthrough
1
A newborn is found on imaging to have periventricular calcifications, along with sensorineural hearing loss identified on a hearing screen.
2
Ask: which congenital infection does this specific calcification pattern point to? CMV — periventricular calcifications specifically, combined with sensorineural hearing loss, is the classic pattern, and CMV is also the single most common congenital infection overall.
3
Contrast: if the imaging instead showed more diffuse intracranial calcifications along with hydrocephalus and chorioretinitis, that combination would point to Toxoplasma instead — a similar-sounding but distinct calcification pattern.
4
This distinction — periventricular calcifications (CMV) versus more diffuse intracranial calcifications with chorioretinitis and hydrocephalus (Toxoplasma) — is exactly the kind of detail exams use to differentiate two TORCH infections that might otherwise seem to overlap.
Exam Application
Exams test matching each TORCH infection to its distinctive findings (Toxoplasma's chorioretinitis/hydrocephalus/calcifications, Rubella's blueberry muffin rash/cataracts/deafness/PDA, CMV's periventricular calcifications/hearing loss, syphilis's saddle nose/Hutchinson's teeth) and specifically that CMV — not Toxoplasma — is the most common congenital infection overall.
⚠ Common Trap
The most common trap is confusing Toxoplasma and CMV, since both cause intracranial calcifications and are frequently tested together. The distinguishing details are the calcification pattern (diffuse/intracranial for Toxo vs. periventricular for CMV) and remembering that CMV, not Toxoplasma, is the most common congenital infection overall.
✓ Quick Self-Check
1. What congenital findings are associated with Toxoplasma?
Chorioretinitis, hydrocephalus, and intracranial calcifications.
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2. What congenital findings are associated with Rubella?
"Blueberry muffin" rash, cataracts, deafness, and PDA (patent ductus arteriosus).
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3. What is the most common congenital infection overall, and what are its classic findings?
CMV; periventricular calcifications and sensorineural hearing loss.
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4. What congenital findings are associated with syphilis?
Saddle nose deformity, Hutchinson's teeth, and interstitial keratitis.
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5. Why is C-section indicated for a mother with active genital herpes lesions at delivery?
To avoid transmitting the virus to the newborn during vaginal delivery.
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