CHAPTER 21
External Diseases of the Eye
This chapter focuses on external diseases of the eye that are seen in the pediatric population. Many of the topics covered in this chapter are also discussed in BCSC Section 8, External Disease and Cornea.
Infectious Conjunctivitis
Bacterial and viral infections are the most common causes of infectious conjunctivitis in children in developed countries. Patients with infectious conjunctivitis commonly present with burning, stinging, foreign-body sensation, ocular discharge, and matting of the eyelids. Symptoms and signs may present unilaterally or bilaterally. The character of the discharge, which can provide some diagnostic help, may be serous, mucopurulent, or purulent. Purulent discharge suggests a polymorphonuclear response to a bacterial infection; mucopurulent discharge suggests a viral or chlamydial infection; and a serous or watery discharge suggests a viral or allergic reaction. Membrane or pseudomembrane formation may be seen in severe viral or bacterial conjunctivitis, Stevens-Johnson syndrome, ligneous conjunctivitis, and chemical burns. Table 21-1 lists common causes of conjunctival injection, or red eye, in infants and children.
Table 21-1
Ophthalmia Neonatorum
Ophthalmia neonatorum refers to conjunctivitis occurring in the first month of life. This condition can be caused by bacterial, viral, and chemical agents. Widespread effective prophylaxis has diminished its occurrence to very low levels in industrialized countries, but ophthalmia neonatorum remains a significant cause of ocular infection, blindness, and even death in medically underserved areas around the world.
Epidemiology and etiology
Worldwide, the incidence of ophthalmia neonatorum is greater in areas with high rates of sexually transmitted disease and poor health care. The prevalence ranges from 0.1% in highly developed countries with effective prenatal and perinatal care to 10% in areas such as East Africa. Because a mother may have multiple sexually transmitted diseases, infants with one type of ophthalmia neonatorum should be screened for other such diseases. Public health authorities should be contacted to initiate evaluation and treatment of other maternal contacts in cases of sexually transmitted
diseases.
The causative organism usually infects the infant through direct contact during passage through the birth canal. Infection can ascend to the uterus, especially if there is prolonged rupture of membranes, so even infants delivered by cesarean section can be infected.
Neisseria gonorrhoeae
Ophthalmia neonatorum caused by Neisseria gonorrhoeae typically presents in the first 3–4 days of life. Patients may present with mild conjunctival hyperemia and discharge. In severe cases, there is marked chemosis, copious discharge, and potentially rapid corneal ulceration and perforation of the eye (Fig 21-1). Systemic infection can cause sepsis, meningitis, and arthritis.
Figure 21-1 Neisseria gonorrhoeae conjunctivitis.
Gram stain of the conjunctival exudate showing gram-negative intracellular diplococci allows for a presumptive diagnosis of N gonorrhoeae infection; treatment should be started immediately. Ophthalmia neonatorum from Neisseria meningitidis has also been reported. Definitive diagnosis is based on culture of the conjunctival discharge. Treatment of gonococcal ophthalmia neonatorum includes systemic ceftriaxone and topical irrigation with saline. Topical antibiotics may be indicated if there is corneal involvement.
Chlamydia trachomatis
Chlamydia trachomatis is an obligate intracellular bacterium that causes neonatal inclusion
conjunctivitis. Onset of conjunctivitis usually occurs around 1 week of age, although onset may be earlier, especially in cases with premature rupture of membranes. Eye infection is characterized by minimal to moderate discharge, mild swelling of the eyelids, and hyperemia with a papillary reaction of the conjunctiva. Severe cases may be accompanied by more copious discharge and pseudomembrane formation. Chlamydial infection in infants differs from that in adults in several ways: in infants, there is no follicular response, membrane formation may occur, and there is greater mucopurulent discharge.
Chlamydial infections can be diagnosed by culture of conjunctival scrapings, polymerase chain reaction, direct fluorescent antibody tests, and enzyme immunoassays. Systemic treatment of neonatal chlamydial disease is indicated because of the risk of pneumonia and otitis media. The treatment of choice is oral erythromycin, 50 mg/kg per day in 4 divided doses for 14 days.
Herpes simplex virus
Infection with herpes simplex virus (HSV) is usually secondary to HSV type 2 and typically presents later than infection with N gonorrhoeae or C trachomatis, frequently in the second week of life. See the discussion of congenital HSV infection in Chapter 28.
Chemical conjunctivitis
Chemical conjunctivitis refers to a mild, self-limited irritation and redness of the conjunctiva occurring in the first 24 hours after instillation of silver nitrate, a preparation used for prophylaxis against ophthalmia neonatorum. This condition improves spontaneously by the second day of life.
Prophylaxis for ophthalmia neonatorum
In 1880, Credé introduced the concept of widespread prophylaxis for gonorrheal ophthalmia neonatorum with 2% silver nitrate. Silver nitrate prophylaxis significantly reduced the incidence of gonorrheal conjunctivitis and is still used in some parts of the world. Silver nitrate is not effective against C trachomatis and thus has been supplanted by agents that act against both N gonorrhoeae and C trachomatis, such as erythromycin and tetracycline ointments.
A clinical trial for ophthalmia neonatorum conducted in Kenya showed that povidone-iodine drops are more effective and less toxic than erythromycin or silver nitrate ointment. Povidone-iodine is particularly useful in developing countries because of its low cost and ease of application.
Bacterial Conjunctivitis
The most common causes of bacterial conjunctivitis in school-aged children are Streptococcus pneumoniae, Haemophilus species, Staphylococcus aureus, and Moraxella. The incidence of infection from Haemophilus has decreased because of widespread immunization. More severe forms of bacterial conjunctivitis accompanied by copious discharge suggest infection with more virulent organisms, including N gonorrhoeae and N meningitidis.
Diagnosis is by clinical presentation. Culture to identify the offending agent is usually not necessary in mild cases but should be done in severe cases. If untreated, symptoms are self-limited but may last up to 2 weeks. A broad-spectrum topical ophthalmic drop or ointment should shorten the course to a few days. Topical medications that are usually effective include polymyxin combinations, aminoglycosides, erythromycin, bacitracin, fluoroquinolones, and azithromycin. The fluoroquinolones are considerably more expensive than other medications and may give rise to drugresistant organisms. Patients with N meningitidis conjunctivitis, and others exposed to these patients, require systemic treatment because of the high risk of meningitis.
Parinaud oculoglandular syndrome
Parinaud oculoglandular syndrome (POS) manifests as unilateral granulomatous conjunctivitis associated with preauricular and submandibular adenopathy that can be very marked (Fig 21-2). Bartonella henselae, a pleomorphic gram-negative bacillus that is endemic in cats and causes catscratch disease, is the most common cause of POS. Other causative organisms include
Mycobacterium tuberculosis, Mycobacterium leprae, Francisella tularensis, Yersinia pseudotuberculosis, Treponema pallidum, and C trachomatis. Cat-scratch disease is usually associated with a scratch from a kitten, but a cat bite or even touching the eye with a hand that has been licked by an infected kitten can cause the disease.
Figure 21-2 Parinaud oculoglandular syndrome. A, Marked follicular reaction in lower fornix. B, Massive enlargement of submandibular lymph node on affected right side. (Courtesy of David A. Plager, MD.)
Serologic testing is an effective means of diagnosing POS. Presence of antibodies to B henselae, detected by indirect fluorescent antibody testing or enzyme immunoassay, can confirm a diagnosis of cat-scratch disease. Treatment can be supportive in mild cases of cat-scratch disease because the disease is self-limited. In more severe cases systemic treatment, usually with azithromycin, may be indicated. Appropriate systemic antibiotics are used to treat the other organisms that cause POS.
Chlamydial infections
Two different diseases can be caused by C trachomatis in children and adolescents: trachoma and adult inclusion conjunctivitis.
Trachoma Trachoma is the most common cause of preventable blindness in the world. This disease is uncommon in Europe and the United States, except in areas of the southern United States and on Native American reservations. It is caused by poor hygiene and inadequate sanitation and is spread from eye to eye or by flies or fomites. Clinical manifestations include acute purulent conjunctivitis, a follicular reaction, papillary hypertrophy, vascularization of the cornea, and progressive cicatricial changes of the cornea and conjunctiva. Diagnosis is made by Giemsa stain, cell culture, or polymerase chain reaction. Treatment includes both topical and systemic erythromycin. Tetracycline can be used in children 8 years of age and older.
Adult inclusion conjunctivitis Adult inclusion conjunctivitis is a sexually transmitted disease that can be