Conjunctivitis Diagnosis: Clinical Features

Conjunctivitis

• Inflammation of the conjunctiva is characterized by specific clinical features, including:
• Type of conjunctival discharge
• Type of conjunctival reaction
• Lymphadenopathy

Conjunctival Discharge

• The nature of the discharge is determined by the causative micro-organism:
• Watery discharge: viral conjunctivitis
• Mucoid or mucopurulent discharge: bacterial conjunctivitis
• Purulent discharge: gonococcal infection and other virulent microorganisms
• Blood-stained discharge: diphtheric conjunctivitis

Conjunctival Reaction

• Redness of the conjunctiva is most intense at the fornices and fades towards the limbus
• Oedema of the conjunctiva (chemosis) may occur due to:
• Acute inflammation of the conjunctiva
• Obstruction to the orbital circulation (e.g., orbital tumor)
• Abnormal blood conditions (e.g., anemia)

Membrane and Pseudomembrane

• Membrane and pseudomembrane formation may occur with virulent microorganisms
• True membrane formation is classic in diphtheric conjunctivitis
• Pseudomembrane formation may occur with strep or staph infections

Spring Catarrh

• An allergic condition excited by exogenous allergens and enhanced by physical factors
• A combination of IgE and cell-mediated delayed immune response
• Symptoms: itching, photophobia, lacrimation, discolouration of the conjunctiva, and ropy discharge
• Signs: three clinical forms of vernal conjunctivitis:
• Palpebral form: cobblestone appearance
• Bulbar form (limbal): gelatinous masses on the limbus and Trantas spots

Treatment

• Dark glasses
• Cold compresses
• Local antihistamine and mast cell stabilizer (Na cromoglycate)
• Local steroids

Phlyctenular Conjunctivitis

• An acute nodular affection of the conjunctiva, commonly at the limbus, surrounded by vascular engorgement
• Occurs mainly in children (3-12 years) as an allergic response to some endogenous toxins
• Symptoms: irritation, photophobia, blepharospasm, and lacrimation
• Signs: a small pinkish-white nodule surrounded by localized vascular engorgement
• Treatment: local application of steroids and local antibiotics if secondary bacterial infection

Pterygium

• A degenerative process in which a triangular fold of the conjunctiva actively invades the cornea

Anatomy of the Conjunctiva

• The conjunctiva is a thin mucous membrane lining the posterior surface of the lid, reflected on the anterior aspect of the eyeball as far as the limbus
• Divided into:
• Palpebral conjunctiva: lines the under surface of the eyelids and extends to the fornix
• Fornix conjunctiva: formed by the reflection of the palpebral conjunctiva onto the anterior portion of the eyeball
• Bulbar conjunctiva: covers the anterior portion of the eyeball until the corneo-scleral junction (limbus)
• Contains the accessory lacrimal glands and goblet cells

Learn about the key clinical features to consider when diagnosing conjunctivitis, including types of conjunctival discharge and reaction. Understand the differences between viral and bacterial conjunctivitis and their characteristic symptoms. Test your knowledge on the diagnosis of conjunctivitis.