Which one is the most common cause of ophthalmia neonatorum?

Appeared in: UPPSC-2021

Explanation

Chlamydia trachomatis is the most frequent infectious agent causing ophthalmia neonatorum, with an incidence of 8.2 per 1,000 births in the United States.
The infection is acquired during passage through the birth canal of an infected mother.
Symptoms typically present later than other causes, usually between 5 and 14 days after birth.
Routine neonatal eye prophylaxis with erythromycin is aimed at preventing gonococcal ophthalmia and is less effective against Chlamydia, contributing to its higher prevalence.

Option B: Candida albicans is a fungus. Fungal infections are a rare cause of neonatal conjunctivitis.
Option C: While Streptococcus species can cause neonatal conjunctivitis, they are a much less frequent cause compared to Chlamydia trachomatis.
Option D: Staphylococcus aureus can cause neonatal conjunctivitis, often acquired in the nursery, but it is not the most common causative organism.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Ophthalmia Neonatorum as background academic context rather than a clinical decision trigger.
Prompt identification of the cause of ophthalmia neonatorum is critical. While Chlamydia is most common, gonococcal conjunctivitis is a medical emergency that can lead to blindness if not treated urgently.
This highlights the importance of comprehensive maternal prenatal screening for sexually transmitted infections (STIs) like Chlamydia and Gonorrhea to prevent vertical transmission.
Nurses play a key role in administering legally mandated ocular prophylaxis to all newborns, which has drastically reduced the incidence of gonococcal blindness.

How to Approach the Question

First, identify the key terms in the question: "most common cause" and "ophthalmia neonatorum" (conjunctivitis of the newborn).
Recall the different infectious and non-infectious causes of this condition.
Consider the impact of routine medical practices. Remember that all newborns receive prophylactic eye ointment. This is primarily to prevent gonococcal infection.
Reason that because gonococcal infection is actively prevented, another organism is likely to be the 'most common'.
Recall that Chlamydia trachomatis is a very common STI and that the prophylaxis is not as effective against it. This makes it the most likely candidate for the most common cause.
Evaluate the other options: Candida (fungal) is rare, and while Staphylococcus/Streptococcus are possible bacterial causes, they are not as prevalent as Chlamydia acquired during birth.

Concept Tested & Keywords

QhvlVXwJ3272Qr1ncGa3mk

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1747-1749

E6 Medicine Harrison 22e Part 1 p. 1513-1515

E6 Obstetrics Williams p. 2-9

Practise the full UPPSC-2021

Attempt every question from this paper in a timed mock, then review the full solution for each one.