Conjunctivitis
Conjunctivitis is an inflammation of the lining of the eye and eyelid caused by bacteria, viruses, chemicals or allergies, fungal, parasites.
- It is characterized by dilatation of the conjunctival vessels, resulting in hyperemia and edema of the conjunctiva, typically with associated discharge.
- It’s the most common cause of red eye usually painless and characterized by pussy or watery discharge.
Types of Conjunctivitis
- Bacterial conjunctivitis :- caused by bacterium e.g. staphylococcus or streptococcus
- Acute viral conjunctivitis:- e.g. herpes simplex
- Allergic conjunctivitis:- caused by allergy e.g. smoke, cosmetic and medicines
Bacterial Conjunctivitis
Predisposing factors for bacterial conjunctivitis
- Flies
- Poor hygienic conditions
- Hot dry climate
- Poor sanitation
- Dirty habits
Causes of Bacterial Conjunctivitis
- Staphylococcus aureus is the most common cause of bacterial conjunctivitis
- Pneumococcus.
- Streptococcus pyogenes (haemolyticus) is virulent and usually produces pseudomembranous conjunctivitis.
- Pseudomonas pyocyanea is a virulent organism, which readily invades the cornea.
- Neisseria gonorrhoeae typically produces acute purulent conjunctivitis in adults and ophthalmic neonatorum in newborn
- Neisseria meningitidis may produce muco-purulent conjunctivitis.
- Corynebacterium diphtheriae causes acute membranous conjunctivitis
Mode of Infection
Conjunctiva may get infected from three sources:-
1.Exogenous infections may spread:
- Directly through close contact
- Vector transmission e.g., flies
- Material transfer e.g. infected fingers of health workers, common towels,handkerchiefs & tonometers
- Local spread may occur from neighbouring structures such as infected lacrimal sac, lids, and nasopharynx.
- Endogenous infections may occur very rarely through blood, e.g., gonococcal and meningococcal infections.
Pathology
- Pathological changes of bacterial conjunctivitis consist of:
- Vascular response. It is characterized by congestion and increased permeability of the conjunctival vessels associated with proliferation of capillaries.
- Cellular response. It is in the form of exudation of polymorphonuclear cells and other inflammatory cells into the substantia propria of conjunctiva as well as in the conjunctival sac.
- Conjunctival tissue response. Conjunctiva becomes edematous. The superficial epithelial cells degenerate, become loose and even desquamate. There occurs proliferation of basal layers of conjunctival epithelium and increase in the number of mucin-secreting goblet cells.
- Conjunctival discharge. It consists of tears, mucus, inflammatory cells, desquamated epithelial cells, fibrin and bacteria. If the inflammation is very severe, diapedesis of red blood cells may occur and discharge may become blood stained.
Acute Bacterial Conjunctivitis
- Acute bacterial conjunctivitis is characterized by marked conjunctival hyperemia and mucopurulent discharge from the eye.
- It is the most common type of bacterial conjunctivitis.
- Common causative bacteria are: Staphylococcus aureus, Pneumococcus and Streptococcus.
Infectious period
The time during which an infected person can infect others thus while the eye discharge is present.
Clinical Presentation
- Typically there is conjunctival infection, especially in the fornices where the blood supply is rich.
- Discharge is variable, but typically is present in the mornings, and on waking the eye is difficult to open because the eyelids are stuck together.
- The eyelids may be red and inflamed.
- The condition may be unilateral or bilateral.
- The vision is always unaffected and there is usually no pain.
- The patient may complain of a gritty or foreign body sensation, some discomfort and very occasionally very mild photophobia.
- Slight blurring of vision due to mucous flakes in front of cornea.
- Flakes of mucopus seen in the fornices, canthi and lid margins is a critical sign
Clinical course and diagnosis
- Mucopurulent conjunctivitis is usually bilateral, although one eye may become affected 1–2 days before the other.
- The disease usually reaches its height in three to four days. If untreated, in mild cases the infection may be overcome and the condition is cured in 10–15 days
Diagnosis
- It is by clinical and/or microscopic examination and culture of discharge from the eye.
- It is usually not possible to tell whether the conjunctivitis is caused by bacteria or viruses without laboratory tests.
Management of bacterial Conjunctivitis
- Clean the eyes and apply topical antibiotics
- Bacterial conjunctivitis usually resolves without treatment
- Topical antibiotics may be needed only if no improvement is observed after 3 days
- Dark goggles should be used to prevent photophobia.
- No bandage should be applied in patients with mucopurulent conjunctivitis. Exposure to air keeps the temperature of conjunctival cul-de-sac low which inhibits the bacterial growth
- No steroids should be applied, otherwise infection will flare up and bacterial corneal ulcer may develop.
- Topical Antibiotics:
- Therefore, treatment may be started with chloramphenicol (1%), or gentamicin (0.3%), or tobramycin 0.3% or framycetin 0.3% eye drops 3–4 hourly in day and ointment used at night will not only provide antibiotic cover but also help to reduce the early morning stickiness.
- Quinolone antibiotic drops such as ciprofloxacin (0.3%), ofloxacin (0.3%), gatifloxacin (0.3%) or moxifloxacin (0.5%) may be used as alternative in severe cases
Chronic Bacterial Conjunctivitis
- Chronic bacterial conjunctivitis also known as ‘Chronic catarrhal conjunctivitis’ or ‘simple chronic conjunctivitis’ is characterized by mild catarrhal inflammation of the conjunctiva.
Viral Conjunctivitis
Viral causes include:
- Adenovirus
- Herpes simplex virus
- Poxvirus
- Mycovirus and Paramyxovirus
Signs of Viral conjunctivitis
- Red/pink eye.
- Chemosis, if severe.
- Follicles may be present on the palpebral conjunctiva.
- Bleeding from conjunctival vessels in severe adenoviral conjunctivitis.
Management/Treatment
- Supportive treatment for amelioration of symptoms is the only treatment required and includes:
- Apply cold compresses
- If photophobia is present, advise patient to wear dark glasses
- Artificial lubricant can be prescribed for patient comfort.
- Topical antibiotics help to prevent superadded bacterial infections.
- Topical antiviral drugs are not beneficial in adenoviral conjunctivitis.
- Topical steroids should not be used during active inflammation as these may enhance viral replication and extend the period of infectivity.
- Weak steroids such as fluorometholone or loteprednol (0.5%) are indicated in patients with subepithelial infiltrates, and in those with membrane formation.
- Full explanation of the condition to increase patient awareness and reduce discomfort.
Preventive measures include:
- Frequent hand washing
- Relative isolation of infected individual
- Avoiding eye rubbing and common use of towel or handkerchief sharing
- Disinfection of ophthalmic instruments and clinical surfaces after examination of a patient is essential.
Allergic Conjunctivitis
- It is the inflammation of conjunctiva due to allergic or hypersensitivity reactions which may be immediate (humoral) or delayed (cellular).
Types
- Simple allergic conjunctivitis
- Seasonal allergic conjunctivitis (SAC)
- Perennial allergic conjunctivitis (PAC)
- Vernal keratoconjunctivitis (VKC)
- Atopic keratoconjunctivitis (AKC)
Simple Allergic Conjunctivitis
- It is a mild, nonspecific allergic conjunctivitis characterized by itching, hyperaemia and mild papillary response.
Etiology
- Simple allergic conjunctivitis, is a type-I immediate hypersensitivity reaction mediated by IgE.
Types
- Seasonal allergic conjunctivitis (SAC). SAC is a response to seasonal allergens such as tree and grass pollens. It is of very common occurrence and may be associated with allergic rhinitis.
- Perennial allergic conjunctivitis (PAC) is a response to perennial allergens such as house dust, animal dander and mite. The onset is subacute, the condition is chronic in nature and occurring all through the year.
Clinical Features
Symptoms
- Intense itching and burning sensation in the eyes associated with watery mucus and mild photophobia.
Signs
- Hyperaemia and chemosis which give a swollen juicy appearance to the conjunctiva.
- Oedema of lids is often present.
Diagnosis
Diagnosis is made from:
- Typical symptoms and signs,
- Normal conjunctival flora, and
- Presence of abundant eosinophils in the discharge.
Treatment
- Elimination of allergens if possible.
- Topical vasoconstrictors like naphazoline, antizoline and tetrahydrozoline provide immediate decongestion.
- Artificial tears like carboxymethyl cellulose provide soothing effect. As they sometimes relieve discomfort in mild cases
- Mast cell stabilizers such as sodium cromoglycate and nedocromil sodium are very effective in preventing recurrences in atopic cases.
- Steroids, if condition is severe
- Cool water poured over the face with the head inclined downward constricts capillaries.
Other forms of Conjunctivitis
Fungal conjunctivitis
it is caused by Candida albicans. Babies can be affected during birth through an infected birth canal.
- Fine white plaques are apparent on the conjunctiva.
- The treatment is with nystatin drops and ointment.
Parasitic conjunctivitis
- In hot climates, parasites causing onchocerciasis (river blindness) and schistosomiasis (bilharzia) can induce conjunctivitis.
Prevention
- Exclude people with conjunctivitis from public places until discharge from the eyes has ceased.
- Good personal hygiene must be followed. Careful hand washing, using soap and warm water.
- Do not share towels and wash clothes
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