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Conjunctivitis

Background knowledge ๐Ÿง 

Definition

  • Conjunctivitis, also known as pink eye, is inflammation of the conjunctiva, the clear membrane covering the white part of the eye and the inner eyelids
  • Can be caused by infections (bacterial, viral), allergies, or irritants
  • Highly contagious if infectious

Epidemiology

  • Common condition affecting all age groups
  • Infectious conjunctivitis is more common in children
  • Allergic conjunctivitis is more frequent in individuals with atopic conditions
  • Bacterial conjunctivitis peaks in the winter and early spring

Aetiology and Pathophysiology

  • Viral: Adenovirus is the most common cause
  • Bacterial: Common pathogens include Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae
  • Allergic: Triggered by allergens such as pollen, dust mites, and animal dander
  • Irritant: Caused by chemicals, smoke, or foreign bodies

Types

  • Viral Conjunctivitis
  • Bacterial Conjunctivitis
  • Allergic Conjunctivitis
  • Irritant Conjunctivitis

Clinical Features ๐ŸŒก๏ธ

Symptoms

  • Redness in the white of the eye or inner eyelid
  • Increased amount of tears
  • Thick yellow discharge that crusts over the eyelashes, especially after sleep (bacterial)
  • Itchy eyes (allergic)
  • Burning eyes
  • Blurred vision

Signs

  • Conjunctival hyperemia
  • Chemosis (swelling of the conjunctiva)
  • Palpebral follicles or papillae
  • Preauricular lymphadenopathy (viral)
  • Purulent discharge (bacterial)
  • Watery discharge (viral or allergic)

Investigations ๐Ÿงช

Tests

  • Clinical diagnosis primarily based on history and examination
  • Swabs for bacterial culture in severe or refractory cases
  • PCR testing for viral pathogens if necessary
  • Allergy testing if allergic conjunctivitis is suspected
  • Fluorescein staining to check for corneal involvement

Management ๐Ÿฅผ

Management

  • Viral: Usually self-limiting, supportive care (e.g., artificial tears)
  • Bacterial: Topical antibiotics (e.g., chloramphenicol)
  • Allergic: Antihistamines and mast cell stabilizers (e.g., olopatadine)
  • Avoid contact lenses during infection
  • Maintain good hygiene to prevent spread
  • Refer to ophthalmologist if symptoms persist or if there is corneal involvement

Complications

  • Keratitis
  • Chronic conjunctivitis
  • Preseptal or orbital cellulitis
  • Corneal ulcers (bacterial)
  • Visual impairment if severe and untreated

Key points

  • Conjunctivitis can be viral, bacterial, allergic, or irritant in origin
  • Diagnosis is primarily clinical, based on history and examination
  • Management depends on the cause; most cases are self-limiting
  • Prevent spread by maintaining good hygiene and avoiding contact lenses during infection
  • Refer to ophthalmology if symptoms persist or worsen

References

  • NICE Clinical Knowledge Summary on Conjunctivitis (https://cks.nice.org.uk/topics/conjunctivitis-infective/)
  • BNF – British National Formulary (https://bnf.nice.org.uk/)
  • NHS Inform – Conjunctivitis (https://www.nhsinform.scot/illnesses-and-conditions/eyes/conjunctivitis)

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