Ординатура / Офтальмология / Английские материалы / Ophthalmology A Short Textbook_Lang_2000

partners of treated patients should all be treated simultaneously with oral tetracycline. Children should be treated with erythromycin instead of tetracycline (see the table in the Appendix for side effects of medications).

Prognosis: The prognosis is good when the sexual partner is included in therapy.

Trachoma

Trachoma (Chlamydia trachomatis serotype A–C) is rare in temperate countries. In endemic regions (warm climates, poor standard of living, and poor hygiene), it is among the most frequent causes of blindness (see Table 4.2 for symptoms, findings, and therapy). Left untreated, the disorder progresses through four stages (Fig. 4.14):

Stage I: Hyperplasia of the lymph follicles on the upper tarsus.

Stage II: Papillary hypertrophy of the upper tarsus, subepithelial corneal infiltrates, pannus formation, follicles on the limbus.

Stages III and IV: Increasing scarring and symptoms of keratoconjunctivitis sicca. The progression is entropion, trichiasis, keratitis, superinfection, ulceration, perforation, and finally loss of the eye.

4.4.2.3Viral Conjunctivitis

Epidemiology: The incidence of epidemic keratoconjunctivitis is high in general, and it is by far the most frequently encountered viral conjunctivitis (see Table 4.2).

Trachoma (Stage II–III).

Fig. 4.14 Prominent tarsal follicles and papillae on the upper and lower eyelids.

94 4 Conjunctiva

Etiology: This highly contagious conjunctivitis is usually caused by type 18 or 19 adenovirus and is spread by direct contact (see also prophylaxis; Figs. 4.15 a and b). The incubation period is eight to ten days.

Symptoms: Onset is usually unilateral. Typical signs include severe illacrimation and itching accompanied by a watery mucoid discharge. The eyelid and often the conjunctivitis are swollen. Patients often also have a moderate influenza infection.

Diagnostic considerations: Characteristic findings include reddening and swelling of the plica semilunaris and lacrimal caruncle and nummular keratitis (Fig. 4.15b) after 8–15 days, during the healing phase.

Epidemic keratoconjunctivitis (viral conjunctivitis).

Fig. 4.15

a Acute unilateral reddening of the conjunctiva accompanied by pseudoptosis.

b After 8 – 10 days coin-like infiltrates (nummular keratitis) appear in the superficial corneal stroma. These may persist for months or years.

Differential diagnosis: The disease runs a well defined clinical course that is nearly impossible to influence and resolves after two weeks. No specific therapy is possible. Treatment with artificial tears and cool compresses helps relieve symptoms. Cortisone eyedrops should usually be avoided as they can compromise the immune system and prolong the clinical symptoms.

Prophylaxis: This is particularly important. Because the disease is spread by contact, the patient should refrain from rubbing his or her eyes despite a severe itching sensation and avoid direct contact with other people such as shaking hands, sharing tools, or using the same towels or wash cloths, etc.

Special hygiene precautions should be taken when examining patients with epidemic keratoconjunctivitis in ophthalmologic care facilities and doctors’ offices to minimize the risk of infecting other patients. Patients with epidemic keratoconjunctivitis should not be seated in the same waiting room as other patients. They should not be greeted with a handshake, and they should be requested to refrain from touching objects where possible. Examination should be by indirect means only, avoiding applanation tonometry, contact lens examination, or gonioscopy. After examination, the examiner should clean his or her hands and the work site with a surface disinfectant.

4.4.2.4Neonatal Conjunctivitis

Epidemiology: Approximately 10% of the newborn contract conjunctivitis.

Etiology (Table 4.3): The most frequent pathogens are Chlamydia, followed by gonococci. Neonatal conjunctivitis is less frequently attributable to other bacteria such as Pseudomonas aeruginosa, Haemophilus, Staphylococcus aureus and Streptococcus pneumoniae, or to herpes simplex. The infection occurs at birth. Chlamydia infections are particularly important because they are among the most common undetected maternal genital diseases in Europe, affecting 5% of all pregnant women. Neonatal conjunctivitis sometimes occurs as a result of Credé’s method of prophylaxis with silver nitrate, required by law in Europe to prevent bacterial infection.

Symptoms: Depending on the pathogen, the inflammation will manifest itself between the second and fourteenth day of life (Table 4.3). The spectrum ranges from mild conjunctival irritation to life-threatening infection (especially with gonococcal infection). Conjunctivitis as a result of Credé’s method of prophylaxis appears with hours but only leads to mild conjunctival irritation.

Acute purulent conjunctivitis in the newborn (gonococcal conjunctivitis) is considered a medical emergency. The patient should be referred to an ophthalmologist for specific diagnosis.

96 4 Conjunctiva

Table 4.3 Differential diagnosis of neonatal conjunctivitis (ophthalmia neonatorum)

Diagnostic considerations: The tentative clinical diagnosis is made on the basis of the onset of the disease (Table 4.3) and the clinical syndrome. For example, gonococcal infections (gonococcal conjunctivitis) are typified by particularly severe accumulations of pus (Figs. 4.16a and b). The newborn’s eyelid are tight and swollen because the pus accumulates under them. When the baby’s eyes are opened, the pus can squirt out under pressure and cause dangerous conjunctivitis in the examiner’s own eyes.

The examiner should always wear eye protection in the presence of suspected gonococcal conjunctivitis to guard against infection from pus issuing from the newborn’s eyes. Gonococci can penetrate the eye even in the absence of a corneal defect and lead to loss of the eye

98 4 Conjunctiva

IV 2 mill. IU daily) or cephalosporin in the presence of penicillinase-produc- ing strains.

Chlamydial conjunctivitis: Systemic erythromycin and topical erythromycin eyedrops five times daily. There is a risk of recurrence where the dosage or duration of treatment is insufficient. It is essential to examine the parents and include them in therapy.

Herpes simplex conjunctivitis: Therapy involves application of acyclovir ointment to the conjunctival sac and eyelids as herpes vesicles will usually be present there, too. Systemic acyclovir therapy is only required in severe cases.

Prophylaxis: Credé’s method of prophylaxis (application of 1% silver nitrate solution) prevents bacterial inflammation but not chlamydial or herpes infection. Prophylaxis of chlamydial infection consists of regular examination of the woman during pregnancy and treatment in appropriate cases.

4.4.2.5Parasitic and Mycotic Conjunctivitis

Parasitic and mycotic forms of conjunctivitis (see Table 4.2) are less important in temperate climates. They are either very rare or occur primarily as comorbidities associated with a primary corneal disorder, such as mycotic infections of corneal ulcers.

4.4.3Noninfectious Conjunctivitis

Table 4.4 provides an overview of pathogens, symptoms, and treatments of noninfectious conjunctivitis.

Acute conjunctivitis is frequently attributable to a series of external irritants or to dry eyes (conjunctivitis sicca). The disorder is unpleasant but benign. Primary symptoms include foreign-body sensation, reddening of the eyes of varying severity, and epiphora. Therapy should focus on eliminating the primary irritant and treating the symptoms.

Acute conjunctivitis should be distinguished from the group of allergic forms of conjunctivitis, which can be due to seasonal influences and often affect the nasal mucosa. Examples include allergic conjunctivitis (hay fever; Fig. 4.17) and vernal conjunctivitis. In giant papillary conjunctivitis, the inflammation is triggered by a foreign body (hard or soft contact lenses. There may also be an additional chronic microbial irritation such microbial contamination of contact lenses. Phlyctenular keratoconjunctivitis is a delayed allergic reaction to microbial proteins or toxins (staphylococcal inflammation). This disease occurs frequently in atopic individuals and is promoted by poor hygiene. The cardinal rule in allergic conjunctivitis is to avoid the causative agent. Desensitization should be performed as a prophylactic measure by a dermatologist or allergist. Long-term treatment includes cromoglycic acid eyedrops to prevent mast cell degranulation. Treatment of acute allergic con-

Seasonal allergic conjunctivitis.

Fig. 4.17 Conjunctival swelling (chemosis) in a patient with hay fever.

junctivitis consists of administering cooling compresses, artificial tears with preservatives, astringent eyedrops (tetryzoline and naphazoline), and, if necessary, surface-acting cortisone eyedrops (fluorometholone).

Ocular-mucocutaneous syndromes such as Stevens–Johnson syndrome

(erythema multiforme), Lyell’s syndrome (toxic epidermal necrolysis), and ocular pemphigoid (progressive shrinkage of the conjunctiva) are clinical syndromes that involve multiple toxic and immunologic causative mechanisms. The clinical course of the disorder is severe, therapeutic options are limited, and the prognosis for eyesight is poor (Fig. 4.18).

Stevens–Johnson syndrome (erythema multiforme).

Fig. 4.18 After several years the conjunctival sac has fused completely (total symblepharon), effectively causing blindness.