Overview
Definition:
Erythromycin eye prophylaxis is the application of erythromycin ophthalmic ointment or drops into the conjunctival sac of a newborn immediately after birth
This is a crucial intervention to prevent neonatal conjunctivitis, specifically ophthalmia neonatorum, which can be caused by bacterial infections transmitted during passage through the birth canal.
Epidemiology:
Before widespread prophylaxis, ophthalmia neonatorum caused significant rates of blindness worldwide
While rates have declined dramatically in countries with established prophylaxis programs, it remains a concern, particularly in settings with limited access to prenatal care and safe delivery practices
*Neisseria gonorrhoeae* and *Chlamydia trachomatis* are the most common causative agents requiring specific management.
Clinical Significance:
Failure to adequately prevent or treat ophthalmia neonatorum can lead to severe ocular morbidity, including corneal ulceration, scarring, and irreversible blindness
Effective prophylaxis is a cornerstone of neonatal eye care, safeguarding vision and contributing to long-term child health outcomes
Understanding indications and alternatives is vital for all pediatric and obstetrics residents.
Indications
Primary Indication:
Routine prophylaxis for all newborns to prevent ophthalmia neonatorum caused by bacteria like *N
gonorrhoeae*, *C
trachomatis*, and other common bacterial pathogens
This is especially critical for infants born to mothers with known or suspected genital tract infections.
Specific Risk Factors:
Increased emphasis on prophylaxis in cases of: maternal infection (gonorrhea, chlamydia), premature rupture of membranes, prolonged labor, or presence of perinatal infections
The goal is to cover a broad spectrum of potential pathogens.
Routine Application:
Recommended by major health organizations like the WHO and CDC for all infants, regardless of maternal infection status, to ensure protection against potential asymptomatic maternal infections or organisms not detected prenatally.
Erythromycin Prophylaxis
Mechanism Of Action:
Erythromycin is a macrolide antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit
It has a broad spectrum of activity against many gram-positive bacteria and some gram-negative bacteria, including common causes of neonatal conjunctivitis.
Dosage And Administration:
Typically, a 0.5% erythromycin ophthalmic ointment is applied as a ribbon into the lower conjunctival sac of each eye within 1 hour of birth
For drops, a single drop is instilled into each eye
The ointment formulation is generally preferred for its longer contact time and efficacy against *C
trachomatis*.
Side Effects:
Transient chemical conjunctivitis, characterized by mild redness and swelling, is the most common side effect and usually resolves within 24-48 hours
It is generally well-tolerated and does not interfere with vision.
Alternatives To Erythromycin
Tetracycline Ophthalmic Ointment:
A 1% tetracycline ophthalmic ointment is another effective alternative, particularly for *Chlamydia trachomatis* prevention
It is also a macrolide-resistant alternative
Like erythromycin, it can cause transient chemical conjunctivitis.
Silver Nitrate Eye Drops:
Historically used, 1% silver nitrate eye drops were effective but are less commonly used now due to significant chemical conjunctivitis and a narrower spectrum of activity compared to erythromycin or tetracycline
It may also be less effective against certain strains of *N
gonorrhoeae*.
Ceftriaxone Injection:
While primarily used for the treatment of established gonococcal ophthalmia neonatorum, a single intramuscular dose of ceftriaxone (25-50 mg/kg, not exceeding 125 mg) can be considered as prophylaxis in high-risk neonates born to mothers with untreated or inadequately treated gonorrhea, in addition to topical prophylaxis
This addresses systemic risk.
Management Of Ophthalmia Neonatorum
Gonococcal Ophthalmia:
Immediate treatment with intravenous or intramuscular ceftriaxone (50 mg/kg per dose, every 12-24 hours for 7 days) and concurrent topical erythromycin or tetracycline ointment
Careful monitoring for complications like sepsis and meningitis is crucial
Consult ophthalmology urgently.
Chlamydial Ophthalmia:
Treatment with oral erythromycin (10-15 mg/kg/dose, four times daily for 14 days)
Topical agents are generally not sufficient
Systemic treatment is essential as chlamydial conjunctivitis can be associated with lower respiratory tract infection
Close follow-up with ophthalmology and pediatrics is required.
Other Bacterial Ophthalmia:
Treatment depends on Gram stain and culture results
Broad-spectrum topical antibiotics (e.g., fortified antibiotic drops) are often used, guided by sensitivities
Systemic antibiotics may be necessary for severe cases or if systemic spread is suspected.
Key Points
Exam Focus:
Recognize the primary indication for erythromycin eye prophylaxis: prevention of ophthalmia neonatorum
Differentiate between prophylaxis and treatment of established conjunctivitis
Know the common causative organisms (*N
gonorrhoeae*, *C
trachomatis*) and their respective treatment regimens
Understand the alternative prophylactic agents and their limitations.
Clinical Pearls:
Apply the ointment carefully into the lower conjunctival sac to ensure adequate coverage
Administer prophylaxis within the first hour of life
Counsel parents on the transient nature of chemical conjunctivitis
Be vigilant for signs of established ophthalmia neonatorum, which requires urgent investigation and treatment
Always consider the possibility of systemic infection with *N
gonorrhoeae* or *C
trachomatis* in neonates with conjunctivitis.
Common Mistakes:
Delaying prophylaxis beyond the first hour of life
Underestimating the severity of gonococcal ophthalmia neonatorum
Using topical agents alone for chlamydial ophthalmia
Failing to consider systemic involvement
Not following up adequately on diagnosed cases of ophthalmia neonatorum, especially chlamydial infections.