cornea (keratitis) Flashcards by Ibrahem Salem Rehiel

Predisposing factors of fungal Keratitis

Trauma with object of plant source (organic matter)
More common in urban / agriculture
Immunocompromised patient

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about the fungal keratitis:

what is the Causetive organisms:

Aspergillus (most common)
Candida

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In case of fungal infection,
Patients come with:

Pain
Lacrimation
Photophobia
Red eye

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about the fungal keratitis:

Signs that you can discover

Signs of inflammation
Blepharospasm
Corneal opacity
Cicrumcorneal injection
Hypopyon

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the Prognosis of fungal keratitis

Bad

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How to dx the fungal keratitis:

Hx of plant trauma comes with pain and photophobia
Culture: Corneal scraping

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Treatment of fungal keratitis

Hospital addmision
Topical natamycin
Systemic Amphotericin B
Therapeutic Keratoplasty
Steroid is Contraindicated

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about parasitic Keratitis:

Caustive organism

Acanthamoeba
normally lives in tap water

So you can expect risk factors and medical history.

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about parasitic Keratitis:

Predisposing factors

Contact lens wear with bad cleaning : using of tap water

Exposure to contaminated water or soil : in non-contact lens users

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about parasitic Keratitis:

Symptoms:

Severe Pain disproportionate with clinical findings
Photophobia
Lacrimation
Red eye

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about parasitic Keratitis:

Signs:

Blepharospasm
Circumcorneal injection
Conreal opacity
Epithelial Pseudodendrites
Ring corneal infiltrate
Radial keratoneuritis

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How to diagnose the parasetic keratitis:

Hx of exposure to contaminated water
comes with severe pain disproportionate with clinical finding
corneal scarping and culture

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Prognosis of parasetic keratitis

Bad

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How to manage parasetic keratitis:

Hospital admission
Debridement
Topical Polyhexamethylenebiguanide(PHMB)
Topical Brolene
Topical steroid : low dose may be useful for persistent inflammation
Therapeutic keratoplasty

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viral keratitis

Types

Herpes simplex keratitis
Herpes zoster ophthalmicus

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viral keratitis

Which one cause Dendritic ulcer

HSV

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viral keratitis

Which one precedes neuralgia

Varicella (primary infection)

viral keratitis

Which one is always comes unilateral (Doesn’t cross midline of the face)

VZV
NB: HSV comes bilateral in some cases

Predisposing factors of Viral keratitis

Fevere
Overexposure to UV light
Trauma
Stress
Menstruation
Immunosuppression

Which one follow distribution of nerve (easy)

HZV

Ocular manifestations of HZ keratitis

Multiple vesicles on skin
Conjunctivitis
Scleritis and episcleritis
Keratitis
uvitis lead to Glaucoma & iris atrophy
Optic neuritis
Retinal necrosis & Detachment
Cranial nerve palsy

Cranial nerve palsy that result from VZV infection can lead to:

3rd: paralytic squint, Ptosis
4th, 6th: paralytiv squint
7th: Ectropion & lagophthalmos

Ocular manifestations of HSV infection

Vesicle on the eyelid
(BlepharoConjunctivitis)
Keratitis
Superficial punctuate keratits
Dendritic ulcer
Uveitis
Discform ulcer
Geographic ulcer

Which type of HSV cause Dendritic ulcer:

Type 1

Type 2 cause genital ulcer (Herpes genetalis)

Primary HSV infection causes:

Vesicles on eyelid (BlepharoConjunctivitis) Stomatitis Gengivitis **No Dendritic ulcer in 1ry infection**

After primary infection HSV become dormant in:

Trigeminal ganglia

Factors that cause reactivation of HSV infection

Influenza Inflammation Stress from the opthalmology exam (keep calm)

What do you think about treating viral corneal ulcer with steroids?

**Contraindicationed**, What kind of idiot would do that? It will turn into **geographic ulcer** You can do topically for skin Or in case of disciform ulcer

BTW, what is dendritic ulcer?

type of corneal ulcer characterized by feather-like or tree-like patterns on the surface of the cornea Cuased by HSV

Dendritic ulcer comes with

superfacial branching ulcer No perforation No vascularizarion Hypesthesia of cornea Terminal bulb

Which virus cause permanent scar?

VZV

Treatment of viral keratitis:

**Acyclovir ointment (zovirax)** 5 times/day for (7-10days) Or **systemic Acyclovir** **Cycloplegic** ED for pain **Tear substitute** to promotes epithelialisation **Antibiotics** to prevent 2ry infection

Discifrom keratitis cause by

Virus immune-mediated reaction **Antibody-Antigen reaction** **NB: The only indication for steroids**

Ocular involvement is usually associated with eruption of vesicles on the skin of tip of nose (Nasociliaru branch) during attack of herpes zoster:

Hutchinson's signs

Corneal ulceration which occur in lagophthalmos:

Exposure keratitis Keratitis with lagophthalmos

Clinical picture of exposure keratitis

Ulceration invelve the lower 1/3 of cornea which is exposed during night as eye rolls up (bell's phenomenonL

Treatment of exposure keratitis

Treat underlying cause (the cause of lagophthalmos) In mild cases: **artificial tear+ antibiotics** In severe cases: **lateral tarsorrhaphy**

Corneal ulceration due to loss of corneal sensation

Neuroparalytic keratitis

Causes of neuroparalytic keratitis

**Trigeminal nerve dysfunction** due to: Trauma Tumor Surgery Inflammation HSV, HZV DM Leprosy

Clinical feature of neuroparalytic keratitis:

No corneal sensation, even severe keratitis may produce little discomfort Reduced vision

Treatment of neuroparalytic keratitis

Treatment underlying cause Keep the eye closed by median Tarsorrhaphy or by ptosis induced with botulinum toxin