Conjunctivitis and red eye — formative SAQs

SAQ 1 (10 marks)

A 4-year-old is brought to the general practice with a two-day history of bilateral red, gritty, watery eyes, follicles on the tarsal conjunctiva and a tender preauricular lymph node. The child had a runny nose and mild fever last week. Vision is normal, and there is no pain or photophobia. A classmate has similar symptoms. [6]

Question: (a) What is the diagnosis and how do you confirm it? (b) Outline the management and the school advice. (c) State the red-flag features that would change your management to urgent ophthalmology referral. (10 marks) [1]

Model answer

(a) Diagnosis and confirmation (3 marks). The most likely diagnosis is viral conjunctivitis, most often adenoviral, suggested by the clear watery discharge, follicles on the tarsal conjunctiva, the tender preauricular lymph node, the accompanying upper-respiratory infection and the sick classmate. The diagnosis is clinical, built on the discharge type, the follicular conjunctival reaction and the preauricular node; routine swabs are not needed for uncomplicated disease. The vision is normal and there is no pain or photophobia, which excludes keratitis here. [6] [1]

(b) Management and school advice (4 marks). Viral conjunctivitis is self-limiting, resolving over one to two weeks, and the management is supportive: lubricating drops and cold compresses for comfort, with strict hygiene to limit spread — frequent hand washing, not sharing towels or pillows, avoiding eye rubbing. Because adenoviral conjunctivitis is highly contagious, advise exclusion from school, childcare and swimming pools until the discharge has settled. Topical antibiotics do not help a viral cause and should not be prescribed. Advise the family to return if pain, photophobia or reduced vision develops. [6]

(c) Red-flag features for urgent referral (3 marks). The red-eye red flags that move the child out of the conjunctivitis basket and into urgent ophthalmology are pain, photophobia, reduced vision, a foreign-body sensation, contact-lens use, trauma, ciliary flush (a ring of redness concentrated around the cornea), a corneal opacity or ulcer, and an abnormal pupil. Each points to keratitis, iritis (uveitis), acute glaucoma, corneal abrasion or a retained foreign body, and each mandates fluorescein staining and urgent referral rather than a topical drop. Conjunctivitis causes discomfort and grittiness, not true pain or visual loss. [5] [1]

SAQ 2 (10 marks)

Question: A 10-day-old term infant presents with mucopurulent conjunctivitis that began at day 8, and the parents describe a worsening staccato cough. The mother had no antenatal sexually-transmitted-infection screening. (a) What is the most likely diagnosis, and what other neonatal cause must you distinguish it from by onset and features? (b) Outline the investigation and the definitive systemic treatment. (c) What must you do for the mother, and what complication are you monitoring for? (10 marks) [11]

Model answer

(a) Diagnosis and the differential (3 marks). The most likely diagnosis is chlamydial ophthalmia neonatorum, the commonest cause, suggested by the onset at day 8 (within the day 5 to 14 window), mucopurulent discharge and the staccato cough of evolving chlamydial pneumonia. The cause that must be distinguished is gonococcal ophthalmia neonatorum (Neisseria gonorrhoeae), which appears earlier (day 2 to 5) with hyperacute, profuse purulent discharge and marked lid oedema and can perforate the cornea within hours. Herpes simplex (any day, with dendritic keratitis) and chemical conjunctivitis (day 1, after prophylaxis, self-limiting) complete the differential. [10] [9]

(b) Investigation and definitive treatment (4 marks). Take conjunctival swabs for Gram stain, bacterial culture and chlamydia testing to confirm the cause. Chlamydial ophthalmia neonatorum requires systemic treatment, not topical drops alone, because topical does not eradicate nasopharyngeal carriage or prevent the pneumonia. The treatment is oral erythromycin 50 mg per kilogram per day in four divided doses for 14 days. A single course may need repeating because the recurrence rate is appreciable. If gonorrhoea were confirmed, the treatment would be systemic ceftriaxone (or cefotaxime in the jaundiced neonate), with saline irrigation and urgent ophthalmology review. [11] [10]

(c) Maternal management and the complication (3 marks). Screen and treat the mother and her partner for sexually-transmitted infection, because the mother's untreated infection is the source and re-exposes the newborn. Treat maternal chlamydia and gonorrhoea as appropriate, and link the family to sexual-health services. The complication to monitor for is chlamydial pneumonia — the afebrile, staccato cough that follows conjunctival infection in a substantial proportion of infants — and the infant is assessed for it at presentation and on review. The family needs a clear safety-net for fever, lethargy, poor feeding or worsening respiratory symptoms. [11] [9]