Conjunctivitis

Question 1

What is the conjunctiva?

Answer 1

The conjunctiva is a transparent mucous membrane that lines both the inner surface of the eyelids and the anterior surface of the eyeball (except the cornea).

Question 2

Parts of the conjunctiva?

Answer 2

1. The part lining the eyelid is called the palpebral conjunctiva, while the membrane lining the anterior eye is called the bulbar conjunctiva.
2. The point at which the palpebral conjunctiva changes to bulbar, a deep fold or recess is formed called the conjunctival fornix and this space between the two conjunctiva is called the conjunctival sac.

Question 3

Structure of the conjunctiva?

Answer 3

1. epithelium
2. stroma
   - adenoid layer
   - fibrous layer

Question 4

What is conjunctivitis?

Answer 4

• Conjunctivitis, or pink eye, is an inflammation of the transparent membrane that lines the eyelid and the eyeball (the conjunctiva).
• It is characterized by dilation of the conjunctival vessels resulting in hyperemia and edema of the conjunctiva

Question 5

Classificaion of conjunctivitis based on etiology?

Answer 5

1. infectious (bacterial, viral)
2. non-infectious (allergic, irritant, secondary to systemic cause )

Question 6

Classification of conjunctivitis based on type of exudate?

Answer 6

1. Purulent
2. Mucopurulent
3. Membranous
4. Pseudomembranous
5. Catarrhal

Question 7

Classification of conjunctivitis based on clinical course?

Answer 7

1. Acute (resolves <4weeks)
2. Chronic (persists >4 weeks)

Question 8

Epidemiology of conjunctivitis?

Answer 8

• Viral conjunctivitis is the most common form accounting for 15 -70% of cases and is more common in adults.
• Bacterial conjunctivitis is more prevalent in children and is responsible for 50 -75% of cases.
• Allergic conjunctivitis affects between 6% and 30% of the general population with a higher prevalence in children.
• There is no significant gender difference.
• Most prevalent eye condition in Malawi at 51%

Question 9

Pathophysiology of conjunctivitis?

Answer 9

1. microbes enter the eye on contact with infected objects
2. inflammation of the eye
3. congestion and increased permeability of blood vessels of the eye
4. swelling, redness, exudates and discharge

Question 10

Pathophysiology of allergic conjuntivitis?

Answer 10

• Allergen comes in contact with the conjunctiva, and this causes a type 1 hypersensitivity reaction.
• There is activation of mast cells due to allergen crosslinking of surface IgE receptors.
• Degranulation occurs and there is release of histamines, cytokines and prostaglandins.
• These substances then induce vascular leakage causing cellular infiltration of eosinophils and neutrophils.

Question 11

Risk factors of bacterial conjunctivitis?

Answer 11

1. Contact with contaminated fingers or oculogenital contact
2. Compromised tear production/drainage
3. Trauma
4. Immunosuppressed status

Question 12

Risk factors for viral conjunctivitis?

Answer 12

Contact with:
1. Contaminated finger
2. Medical instruments
3. Swimming pool water
4. Personal items from an infected person

Question 13

Risk factors for allergic conjunctivitis?

Answer 13

History of non-ocular allergic conditions eg eczema

Question 14

Clinical features of conjunctivitis?

Answer 14

1. Acute onset of redness
2. Grittiness
3. Photophobia
4. Burning
5. Eyelid edema and erythema
6. Discharge
   > watery - viral
   > mucoid - bacterial
   > mucopurulent or purulent - bacterial
7. Itching - allergic

Question 15

Causes of bacterial conjunctivitis?

Answer 15

Most commonly caused by
1. Staphylococcus epidermidis
2. Staphylococcus aureus
3. Streptococcus pneumoniae
4. Hemophilus influenzae
5. Moraxella lacunata.

Question 16

Describe gonoccocal conjunctivitis?

Answer 16

• Caused by Neisseria gonorrhea, a gram-negative diplococcus.
• It is sexually transmitted
• Incubation period of 3–5 days in adults and 1–3 days in neonates.
• In neonates it causes ophthalmia neonatorum (happens in first month of life) which is potentially life-threatening and can cause systematic complications

Question 17

Describe chlamydial conjunctivitis?

Answer 17

• Caused by Chlamydia trachomatis serotypes D-K
• Usually occurs in sexually active adults and adolescents
• Almost always sexually transmitted although occasional eye-to-eye infection is reported
• It also occurs in neonates

Question 18

Describe trachoma?

Answer 18

• Accounts for 10-15% of global blindness and is the leading preventable cause
• Caused by Chlamydia trachomatis serotypes A, B, Ba and C
• It is a chronic/recurrent conjunctivitis
• Occurs in crowded areas and areas of poor hygiene
• Common fly is the vector

Question 19

Elimination strategy for trachoma?

Answer 19

SAFE
S - surgery for advanced disease
A - antibiotics to clear infection
F - facial cleanliness
E - environmental improvement to reduce transmission

Question 20

Causes of viral conjunctivitis?

Answer 20

1. adenovirus
2. Molluscum contagiosum
3. Herpes simplex

Question 21

Describe adenoviral conjunctivitis?

Answer 21

Adenoviral conjunctivitis is highly contagious, and the spectrum of presentation may be generalized into 2 distinct syndromes:
1. Pharyngoconjunctival fever- aerosol transmission, usually post upper respiratory tract infection
2. Epidemic keratoconjunctivitis- transmission by contact (fingers, instruments), there is an 80% chance of developing keratitis

Question 22

Describe molluscum contagiosum conjunctivitis?

Answer 22

• Molluscum contagiosum conjunctivitis is common in children/ young adults and profuse lesions are seen with HIV infection.
• These patients present with chronic history of umbilicated nodule at the lid margin.

Question 23

Describe allergic conjunctivitis?

Answer 23

• This occurs due to exposure of the lid surface to a transient allergen.
• It is a type 1 hypersensitivity reaction

Question 24

The types of allergic conjunctivitis?

Answer 24

1. Seasonal
2. Vernal
3. Atopic
4. Acute

Question 25

Ddx for conjunctivitis?

Answer 25

1. preseptal/orbital cellulitis 2. traumatic eye injuries 3. acute angle closure glaucoma 4. keratitis 5. scleritis 6. subconjunctival hemorrhage 7. anterior uveitis 8. corneal ulcer 9. episcleritis 10. blepharitis

Question 26

Investigations of conjunctivitis?

Answer 26

The diagnosis of conjunctivitis is usually clinical. However, if other ddx are being considered, the following can help to rule them out or identify the cause: 1. Visual Acuity Test 2. Fluorescein Stain 3. Slit Lamp Examination 4. Swab for Gram stain and Culture

Question 27

Supportive therapy for conjunctivitis?

Answer 27

1. Refrigerated artificial tears 2. Cleaning discharge from eyes 3. Compresses (warm/cold) 4. Discontinuation of contact lens use if applicable

Question 28

Bacterial conjunctivitis treatment?

Answer 28

5–7-day course of topical broad-spectrum antibiotics

Question 29

Viral conjunctivitis treatment?

Answer 29

Usually self-limited and only requires supportive therapy but start tailored treatment if necessary e.g. topical antiretroviral therapy for HSV conjunctivitis.

Question 30

Allergic conjunctivitis treatment?

Answer 30

1. Combined vasoconstrictor/antihistamine e.g naphazoline/pheniramine 2. Histamine H1 receptor antagonists e.g azelastine 3. Oral antihistamines e.g cetirizine 4. Corticosteroids

Question 31

Bacterial conjunctivitis prognosis?

Answer 31

Usually self-limiting. Rarely causes complications if treated properly. Good prognosis- full recovery expected.

Question 32

Prognosis for viral conjunctivitis?

Answer 32

- Self-limiting resolving in 1-2 weeks - May get worse before it gets better. - Highly contagious- common outbreaks. - Good prognosis but may develop subepithelial corneal infiltrates in some cases.

Question 33

Prognosis for allergic conjunctivitis?

Answer 33

Chronic or seasonal- flares with exposure to allergens (pollen, dust, pets etc.) Excellent prognosis with avoidance of allergens or use of antihistamines.

Question 34

Complications of bacterial conjunctivitis?

Answer 34

1. Corneal ulcer (especially with aggressive organisms like Neisseria gonorrhoeae or Pseudomonas) 2. Keratitis 3. Vision loss (very rare) 4. Conjunctival scarring

Question 35

Viral conjunctivitis complications?

Answer 35

1. Subepithelial corneal infiltrates 2. Keratitis 3. Secondary bacterial infection (if epithelial barrier is damaged) 4. Symblepharon (rare) - adhesions between eyelid and eyeball

Question 36

Allergic conjunctivitis complications?

Answer 36

1. Keratitis (in severe cases) 2. Conjunctival scarring (rare, chronic severe allergies)