Definition

Conjunctivitis is an inflammatory process involving the surface of the eye and characterized by vascular dilation, cellular infiltration, and exudation. Two forms of the disorder are distinguished:

❖ Acute conjunctivitis. Onset is abrupt and initially unilateral with inflammation of the second eye within one week. Duration is less than four weeks.

❖ Chronic conjunctivitis. Duration is longer than three to four weeks.

Epidemiology: Conjunctivitis is one of the most frequent eye disorders.

Etiology: Causes of conjunctivitis may be fall into two broad categories:

- bacterial

- viral

- parasitic

- mycotic

- from a persistent irritation (such as lack of tear fluid or uncorrected refractive error; see Fig. 4.4)

- allergic

- toxic (due to irritants such as smoke, dust, etc.)

- as a result of another disorder (such as Stevens-Johnson syndrome).

Symptoms: Typical symptoms exhibited by all patients include reddened eyes and sticky eyelids in the morning due to increased secretion. Any conjunctivitis also causes swelling of the eyelid, which will appear partially closed (pseudoptosis). Foreign-body sensation, a sensation of pressure, and a burning sensation are usually present, although these symptoms may vary between individual patients. Intense itching always suggests an allergic reaction. Photophobia and lacrimation (epiphora) may also be present but can vary considerably. Simultaneous presence of blepharospasm suggests corneal involvement (keratoconjunctivitis).

Diagnostic considerations: There are many causes of conjunctivitis, and the clinical picture and symptoms can vary considerably between individual patients. This makes it all the more important to note certain characteristic findings that permit an accurate diagnosis, such as the type of exudation, conjunctival findings, or swollen preauricular lymph nodes (Table 4.1).

Hyperemia. Reddened eyes are a typical sign of conjunctivitis. The conjunctival injection is due to increased filling of the conjunctival blood vessels, which occurs most prominently in the conjunctival fornices. Hyperemia is present in all forms of conjunctivitis. However, the visibility of the hyperemic vessels and their location and size are important criteria for differential diagnosis. One can also distinguish conjunctivitis from other disorders such as scleritis or keratitis according to the injection (Fig. 4.6).The following types of injection are distinguished.

❖ Conjunctival injection (bright red, clearly visible distended vessels that move with the conjunctiva, decreasing toward the limbus; Fig.4.7).

❖ Pericorneal injection (superficial vessels, circular or circumscribed in the vicinity of the limbus).

- Forms of conjunctival injection

Conjunctival

Conjunctival disorders; conjunctivitis

Pericorneal

Conjunctival disorders near the cornea:

- rosacea

- corneal lesions near the limbus

- foreign body

- herpetic keratitis

Fig.4.6

Mixed

Corneal disorders with intraocular irritation;

corneal ulcerations

- Forms of conjunctival injection

Conjunctival

Conjunctival disorders; conjunctivitis

Mixed

Corneal disorders with intraocular irritation;

corneal ulcerations

Pericorneal Plexus

Pericorneal

Conjunctival disorders near the cornea:

- rosacea

- corneal lesions near the limbus

- foreign body

- herpetic keratitis

Fig.4.6

Ciliary

Disorders of deeper tissues and intraocular structures:

- episcleritis

- scleritis

- disciform keratitis

- iritis

- cyclitis

Ciliary

Disorders of deeper tissues and intraocular structures:

- episcleritis

- scleritis

- disciform keratitis

- iritis

- cyclitis

Table 4.1 Symptoms and findings in conjunctivitis as they relate to various forms of the disorder

Symptom or finding

Bacterial conjunctivitis

Chlamydial conjunctivitis

Viral conjunctivitis

Allergic conjunctivitis

Toxic conjunctivitis

Itching

Hyperemia (reddened eye)

++

+

+

+

+

Bleeding

+

-

+

-

-

Discharge

Purulent; yellow crusts

Mucopurulent

Watery

Ropy white, viscous

-

Chemosis

++

-

+

++

+

Lacrimation (epiphora)

+

+

++

+

+

Follicles

-

++

+

+

+

Papillae

+

-

+

-

Pseudomembranes, membranes

-

-

-

Swollen lymph nodes

+

+

++

-

-

Pannus formation vi

Pannus formation

Concurrent keratitis

+

-

Fever or angina

-

+

-

-

Results of cytologic smear

Granulocytes, bacteria

Intracytoplasmic inclusions in epithelial cells, leukocytes, plasma cells, lymphocytes

Lymphocytes, monocytes

Eosinophilic granulocytes, lymphocytes

Epithelial cells, granulocytes, lymphocytes

— Conjunctival injection.

— Conjunctival injection.

Redeneded Conjuctivital Membrane
Fig. 4.7 Clearly visible, bright red, distended conjunctival vessels, decreasing toward the lim-bus of the cornea.

❖ Ciliary injection (not clearly discernible, brightly colored nonmobile vessels in the episclera near the limbus).

❖ Composite injection (frequent).

Discharge. The quantity and nature of the exudate (mucoid, purulent, watery, ropy, or bloody) depend on the etiology (see Table 4.1).

Chemosis (Fig.4.8). This may range from the absence of any conjunctival thickening to a white glassy edema and swelling of the conjunctiva projecting from the palpebral fissure (chemosis this severe occurs with bacterial and allergic conjunctivitis).

Epiphora (excessive tearing). Illacrimation should be distinguished from exudation. Illacrimation is usually reflex lacrimation in reaction to a conjunc-tival or corneal foreign body or toxic irritation.

Follicle. Lymphocytes in the palpebral and bulbar conjunctiva accumulate in punctate masses of lymph tissue cells that have a granular appearance. Follicles occur typically in viral and chlamydial infections (Fig. 4.9).

Papillae. Papillae appear as polygonal "cobblestone" conjunctival projections with a central network of finely branching vessels. They are a typical sign of allergic conjunctivitis (Fig. 4.10).

Membranes and pseudomembranes. These are conjunctival reactions to severe infectious or toxic conjunctivitis. They form from necrotic epithelial tissue and either can be easily removed without bleeding (pseudomembranes) or leave behind a bleeding surface when they are removed (membranes; Figs. 4.11 a, b).

Conjunctival Chemosis.

Conjunctival Chemosis.

Fig. 4.8 White glassy edema and swelling of the conjunctiva.

Fig. 4.8 White glassy edema and swelling of the conjunctiva.

— Follicular conjunctivitis.

— Follicular conjunctivitis.

Allergic Conjunctivitis Pseudomembrane
Fig. 4.9 Punctate masses of lymph tissue cells of a granular appearance.

Swollen lymph nodes. Lymph from the eye region drains through the preauricular and submandibular lymph nodes. Swollen lymph nodes are an important and frequently encountered diagnostic sign of viral conjunctivitis.

Pannus formation. Conjunctival or vascular ingrowth between Bowman's layer and the corneal epithelium in the upper circumference.

H The combination and severity of individual symptoms usually provide essential information that helps to identify the respective presenting form of conjunctivitis.

— Papillary conjunctivitis.

— Papillary conjunctivitis.

Pannus Foration Cornea

conjunctival projections.

Fig. 4.10 Eversion of the upper eyelid reveals

"cobblestone"

conjunctival projections.

Fig. 4.10 Eversion of the upper eyelid reveals

"cobblestone"

Granulomas. These are inflamed nodes of conjunctival stroma with circumscribed areas of reddening and vascular injection. They can occur with systemic disorders such as tuberculosis or sarcoidosis or may be exogenous, such as postoperative suture granulomas or other foreign-body granulomas. Granulomas occur in conjunction with swollen preauricular and subman-dibular lymph nodes in disorders such as Parinaud's oculoglandular syndrome. Granulomas are not a sign of conjunctivitis in the strict sense and for that reason have not been included as symptoms or findings in Table 4.1.

Examination methods: Slit lamp examination.

The nature and extent of vascular injections, discharge, conjunctival swelling, etc. are evaluated using a slit lamp.

Eyelid eversion. This is performed to examine the upper and lower eyelids for the presence of follicles, papillae, membranes, and foreign bodies.

If the diagnosis is uncertain or what appears to be bacterial conjunctivitis does not respond to antibiotics, a conjunctival smear (Fig. 4.12) should be obtained for microbiological examination to identify the pathogen. Cotton swabs with sterile shipping tubes are commercially available; special test kits with specific cultures are available for detecting chlamydiae.

An antibiotic that is not effective in treating what appears to be bacterial conjunctivitis should be discontinued. A conjunctival smear should then be obtained 24 hours later. Microbiological examination to identify the pathogen is indicated for any conjunctivitis in children.

Epithelial smear. This is used to detect chlamydiae in particular and to more clearly identify the pathogen in general. A scraping of conjunctival

Membranous conjunctivitis.

Membranous conjunctivitis.

Figs. 4.11 a, b Genuine membranes (a) leave behind a bleeding surface when hey are removed (b).
Image Membranous Conjunctivitis

epithelium is smeared on a slide and dyed with Giemsa and Gram stain. Cytologic findings provide important information about the etiology of the conjunctivitis.

❖ bacterial conjunctivitis: granulocytes with polymorphous nuclei and bacteria;

❖ viral conjunctivitis: lymphocytes and monocytes;

❖ chlamydial conjunctivitis (special form of bacterial conjunctivitis): composite findings of lymphocytes, plasma cells, and leukocytes; characteristic intracytoplasmic inclusion bodies in epithelial cells may also be present (see Fig.4.13);

— Conjunctival smear for microbiological examination.

— Conjunctival smear for microbiological examination.

Conjunctival Smear

Fig. 4.12 The lower eyelid is slightly everted and a smear of the conjunctival secretion is ob tained with a cotton swab.

Fig. 4.12 The lower eyelid is slightly everted and a smear of the conjunctival secretion is ob tained with a cotton swab.

❖ allergic conjunctivitis: findings primarily include eosinophilic granulo-cytes and lymphocytes;

❖ mycotic conjunctivitis (very rare): the Giemsa or Gram stain will reveal the hyphae.

Irrigation. Conjunctivitis will occur occasionally in asymptomatic dacryocystitis (see p. 60) or canaliculitis (see p. 61) as a result of continuous scattered spread of bacteria. The lower lacrimal system should always be irrigated in the presence of inflammation that recurs or resists treatment to verify or exclude that it is the source of the inflammation.

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Responses

  • ROSE
    What is hyperemia and injection as related to the eye?
    3 years ago
  • ROBIN
    What is ciliary injection?
    8 months ago

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