Update on neonatal conjunctivitis

Past, present and future in the management of ophthalmia neonatorum

Conjunctivitis in the newborn, also called ophthalmia neonatorum (ON), occurs within the first month of life and can have a chemical, viral or bacterial aetiology.

Prevalence

Conjunctivitis in the newborn is the most common eye disease in newborns, affecting 1.2% to 12% of newborns worldwide, and is a significant cause of corneal blindness.

To date, it is estimated that each year there are about 5 million cases by ophthalmia neonatorum mainly in developing areas, but also in industrialised countries.

Gonococcal conjunctivitis in new-born babies

Neonatal gonococcal conjunctivitis, caused by Neisseria gonorrhoeae, is predominantly contracted by the newborn during birth following passage through the infected birth canal, but can also be contracted in utero through ascending infection.

Neonatal gonococcal conjunctivitis affects 30-50% of infants exposed to the micro-organism and presents itself within 3-4 days after birth as a severe hyperacute conjunctivitis.

Course and complications

It is characterised by a rapid and progressive course, is usually bilateral, with oedema of the eyelids, conjunctival chemosis and mucopurulent secretions.

Gonococcal conjunctivitis can have devastating consequences if not treated promptly, as scarring can lead to sight-threatening corneal opacities.

N. gonorrhoeaeis also able to penetrate the intact cornea leading to perforation or endophthalmitis within 24-48 h of infection.

This infection can also spread systemically causing meningitis and sepsis.

Therapy consists of ceftriaxone 20-25 mg/kg (max. 125 mg) or cefotaxime 100 mg/Kg.

Conjunctivitis in the newborn: Chlamydia trachomatis

Another pathogen transmitted from the mother to the newborn during birth is the Chlamydia trachomatisThis bacterium is the most common cause of infectious neonatal conjunctivitis, affecting around 100,000 newborn babies in developing countries every year.

Prevalence

L'ophthalmia neonatorum by Chlamydia is more prevalent than by Neisseria, but has historically been underestimated due to a lack of appropriate diagnostic techniques.

In 2012, among adults aged between 15 and 49 years, a global estimate was made, 128 million cases of Chlamydia infections and the risk of developing conjunctivitis in infants exposed to the micro-organism ranges from 8% to 44%.

Course and complications

The ocular conjunctivitis due to Chlamydia typically presents 5-14 days after delivery, with unilateral or bilateral watery or mucopurulent discharge; it may be accompanied by eyelid oedema, papillary conjunctivitis and pseudomembranous formations.

If left untreated, the conjunctival healing and corneal can be severe, leading to blindness.

More than 50% of newborns with Chlamydia conjunctivitis have concomitant systemic infections in the genital tract, nasopharynx or lungs, so treatment with systemic antibiotics is essential.

Treatment

The currently accepted regimen for neonates is oral erythromycin 50 mg/kg/day in four divided doses over 14 days. For the mother and partner, azithromycin (20 mg/kg, single dose) may be used.

Nosocomial conjunctivitis

In addition to pathogens transmitted through childbirth theophthalmia neonatorum can be caused, albeit more rarely, by bacteria present in the hospital environment, of which those most frequently isolated are Staphylococcus aureus, Haemophylus influenzae and, in general, Gram-negative bacteria.

Prevalence

The highest infection rates with these micro-organisms were found in patients hospitalised for more than two days, including premature infants (75.4% of cases), undergoing mechanical ventilation (46.7%), parenteral nutrition (13.6%) and undergoing phototherapy (6.8%).

These infections can be treated with broad-spectrum topical antibiotics.

Herpetic conjunctivitis

Neonatal conjunctivitis can also be caused by Herpes Simplex Virus (HSV), in which case it typically appears 6-14 days after birth as a follicular form associated with vesicles of the eyelid or periorbital skin and may cause dendritic keratitis.

In confirmed cases, or in the presence of herpetic keratitis, patients are treated with systemic acyclovir 20 mg/kg for 14-21 days.

Chemical conjunctivitis

Finally, another cause of neonatal conjunctivitis are the chemical agentsincluding silver nitrate administered in Credé prophylaxis. This type of ophthalmia presents in a mild and purulent manner within the first 24 hours of life. Replacing silver nitrate drops with antibiotic ointment significantly reduced the incidence of chemical conjunctivitis. This condition is self-limiting, usually resolving within 1-2 days even without treatment.

Neonatal conjunctivitis prophylaxis

There are four strategies for the prevention of ophthalmia neonatorum:

  1. primary prevention the spread of infections transmitted through childbirth;
  2. secondary screening of pregnant women for genital infections;
  3. prophylaxis topical or systemic at birth;
  4. tertiary prevention through early diagnosis and treatment of eye infections in infants.

In Italy prophylaxis is performed by law (Ministerial Decree 11 October 1940, Art. 15; Official Gazette 23 October, no. 249) within an hour of delivery and involves the use of an antiseptic 1% silver nitrate solution or an antibacterial erythromycin or tetracycline eye drops. However, with the onset of Neisseria gonorrhoeae resistant to antibiotics the prophylactic efficacy of erythromycin and tetracycline has been reduced. In this respect, another prophylactic agent used is the iodiopovidone which is assumed to have many advantages over silver nitrate, erythromycin and tetracycline, including low cost, high availability, broader antibacterial spectrum and lack of bacterial resistance development; the disadvantage is the associated higher rates of chemical conjunctivitis.

Despite the progress made in prophylaxis, the best method for preventing neonatal conjunctivitis remains prenatal care with the recognition and treatment of infections during pregnancy, in this regard theWorld Health Organisation (WHO) found in its global incidence report that among women infected with C. trachomatis 70-75% is asymptomatic, thus claiming that all pregnant women should be screened regardless of symptoms

The control ofophthalmia neonatorum also falls under Vision 2020another global initiative that the WHO launched in 1999 in collaboration with theInternational Agency for the Prevention of Blindness with the aim of eliminating avoidable blindness by 2020. The control of childhood blindness is a top priority of this plan and it has been estimated that the 4% of all global blindness is infantile and the 45% of childhood blindness is avoidable

Vision 2020: The Right to Sight

Vision 2020 is an ambitious international campaign that aims to eliminate the main causes of avoidable blindness in the world by the year 2020.

The campaign, devised by cbm International, found immediate support and collaboration from a group of Non-Governmental Organisations (NGOs) that, together with cbm and the World Health Organisation (WHO), formed a Task Force.

More than 25 countries are involved, with over 200 projects for the prevention and treatment of the main and most widespread forms of curable blindness.

Antibiotic resistance and neonatal conjunctivitis

Today we need to curb the inappropriate administration of antibiotics. It would be desirable to acquire data on the number of neonatal conjunctivitis due to Chlamydia trachomatis and Neisseria gonorrhoeae, on the use of conjunctival antibiotics to the newborn at birth and the criteria that lead to their administration, and to produce a unified recommendation that contributes to the containment of inappropriate antibiotic use.

 

Bibliografia

Kapoor VS, Whyte R, Vedula SS. Interventions for preventing ophthalmia neonatorum. Cochrane Database of Systematic. Reviews 2016, Issue 9. Art. No.: CD001862. DOI: 10.1002/14651858.CD001862.pub3.

S Andalibi, M Haidara, N Bor, Moran Levin. An Update on Neonatal and Pediatric Conjunctivitis. 2015, Curr Ophthalmol Rep. DOI 10.1007/s40135-015-0080-x.

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