Opthal: Herpes Simplex Keratitis: Free MSRA Podcast

👁️ Herpes Simplex Keratitis (HSK) – MSRA Deep Dive DefinitionHerpes Simplex Keratitis (HSK) is viral inflammation and ulceration of the cornea caused mostly by herpes simplex virus type 1 (HSV-1).It is the leading infectious cause of blindness in developed countries. Causes & Risk FactorsHSV-1 (cold sore virus): Most common causeHSV-2 (rare, typically in neonates)Primary infection OR reactivation from dormant virus in trigeminal nerveReactivation triggers:Previous ocular HSV infectionImmunosuppressionCorticosteroid eye dropsTrauma to the eyeUV light exposureStress, fever, or other illnesses PathophysiologyVirus infects corneal epithelium → local replication → immune response and inflammationClassic sign: Dendritic ulcer ("branching" appearance) visible with fluorescein under blue lightDamage from both direct viral effect & host immune responseRecurrences due to latent virus in trigeminal ganglion SymptomsRed, painful eyePhotophobia (light sensitivity)Watery eyes (epiphora)Gritty/foreign body sensationBlurred visionUnilateral (usually one eye)Mnemonic: Red,Sore, Light-Sensitive Eye Signs (Examination)Dendritic (branching) ulcer on cornea (with fluorescein)Conjunctival rednessDecreased corneal sensationSometimes mild lid swellingRecurrent cases may have corneal scarring DiagnosisClinical: Dendritic ulcer seen with fluorescein staining and slit lamp exam is usually diagnosticPCR/corneal swab: Only in atypical, severe, or unresponsive casesAlways consider Herpes Zoster Ophthalmicus, bacterial or fungal keratitis in differential EpidemiologyIncidence in UK: ~1 in 5,000 per yearCommon, especially in adults ManagementUrgent ophthalmology referral (specialist management needed)Antivirals:Topical aciclovir (or ganciclovir) ointmentOral aciclovir in recurrent or severe casesAvoid corticosteroids (unless specifically prescribed by a specialist with antiviral cover, e.g., for stromal keratitis)Supportive: Lubricants for comfortPatient education: About recurrence risk and triggers PrognosisGood if treated early—most recover with minimal long-term damageRecurrences are commonUntreated/severe cases: Can lead to permanent corneal scarring, reduced vision, or even corneal perforation ComplicationsCorneal scarringVision lossCorneal thinning/ulcerationNeovascularisation (new vessels in cornea)Secondary bacterial infectionHerpetic stromal keratitis (deeper inflammation)Corneal perforation (very rare) Key Revision Resources (Full URLs)Revision Notes:https://www.passthemsra.com/topic/herpes-simplex-keratitis-revision-notes/Flashcards:https://www.passthemsra.com/topic/herpes-simplex-keratitis-flashcards/Accordion Q&A Notes:https://www.passthemsra.com/topic/herpes-simplex-keratitis-accordion-qa-notes/Rapid Fire Quiz:https://www.passthemsra.com/topic/herpes-simplex-keratitis-rapid-quiz/HSK Quiz:https://www.passthemsra.com/quizzes/herpes-simplex-keratitis/Main Ophthalmology/MSRA Revision Sites:https://www.passthemsra.comhttps://www.freemsra.com 🏁 Summary TakeawaysHSK = HSV-1 infection of the corneaClassic dendritic ulcer (think branches on the cornea)Red, painful, light-sensitive eyeNeeds urgent specialist referralAntiviral therapy is mainstayCorticosteroids are dangerous unless prescribed by a specialistRecurrences are common, can lead to scarring/vision loss #MSRA #Ophthalmology#HerpesSimplexKeratitis #Revision #PasstheMSRA #FreeMSRA #EyeEmergency#DendriticUlcer