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. It 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 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 neonate during birth following passage through the infected birth canal, but can also be contracted in utero by ascending infection. Neonatal gonococcal conjunctivitis affects 30-50% of infants exposed to the micro-organism and presents within 3-4 days after birth as a severe hyperacute conjunctivitis. 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. 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%. 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 infants with Chlamydia conjunctivitis have concomitant systemic infections in the genital tract, nasopharyngeal tract or lungs, so treatment with systemic antibiotics is essential.
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.
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.
The highest infection rates with these micro-organisms were found in patients hospitalised for more than two days, including premature neonates (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.
Neonatal conjunctivitis can also be caused by Herpes Simplex Virus (HSV), in this case typically arises 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.
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:
- primary prevention the spread of infections transmitted through childbirth;
- secondary screening of pregnant women for genital infections;
- prophylaxis topical or systemic at birth;
- 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.
Bibliography:
Dr. Carmelo Chines
Direttore responsabile
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