Download MBBS (Bachelor of Medicine and Bachelor of Surgery) 3rd Year (Third Year) Ophthal Viral Keratitis Topic Handwritten Notes
Rol of Antibiotics
Affect both conjunctiva and cornea
Common viral infections
Herpes simplex keratitis
Herpes zoster ophthalmicus
Adenovirus keratitis
HERPES SIMPLEX KERATITIS
ETIOLOGY
Herpes simplex virus (HSV).
It is a DNA virus. Its only natural host is man.
Basically, HSV is epitheliotropic but may become neurotropic.
HSV is of two types:
v HSV type I typically causes infection above the waist
v HSV type II below the waist (herpes genitalis).
HSV-II has also been reported to cause ocular lesions.
MODE OF INFECTION
? HSV-I infection. It is acquired by kissing or coming in close
contact with a patient suffering from herpes labialis.
? HSV-II infection. It is transmitted to eyes of
neonates through infected genitalia of the mother
OCULAR LESIONS OF HERPES
SIMPLEX
RECURRENT HERPES
PRIMARY HERPES
v 1. Active epithelial keratitis
v 1. Skin lesions
? Punctate epithelial keratitis
v 2. Conjunctiva-acute
? Dendritic ulcer
fol icular conjunctivitis
? Geographical ulcer
v 2. Stromal keratitis
v 3. Cornea
i. Disciform keratitis;
? Fine epithelial punctate
i . Diffuse stromal necrotic
keratitis
Keratitis
? Coarse epithelial punctate
v 3. Trophic keratitis (meta-
keratitis
herpetic)
? Dendritic ulcer
v 4. Herpetic iridocyclitis
PRIMARY OCULAR HERPES
Primary infection involves nonimmune person.
It typical y occurs in children of 6 months til 5 years of age and
in teenagers.
CLINICAL FEATURES
1. Systemic features: mild fever, malaise, non-suppurative
lymphadenopathy.
Rarely, severe morbidity can result from multi-system failure.
Disease may be fatal when encephalitis develops.
2. Skin lesions : Vesicular lesions involving skin of face, lips, lids,
periorbital region and the lid margin (vesicular blepharitis).
3. Ocular lesion :
? Acute follicular conjunctivitis with regional lymphadenitis
? Keratitis: coarse punctate or diffuse branching epithelial
keratitis that does not usual y involve the stroma.
Primary infection is usual y self-limiting
but virus travels up to the trigeminal ganglion and establish
latent infection
Recurrent Ocular Herpes
The virus which lies dormant in the trigeminal ganglion,
periodical y reactivates and replicates. The reactivated virus
travels down along the trigeminal nerve to cause recurrent
infection. It is not associated with systemic features and
typical y is a unilateral disease.
Predisposing stress stimuli which trigger an attack include
fever such as malaria, flu, exposure to UV rays, general il
health, emotional or physical exhaustion, mild trauma,
menstrual stress, fol owing administration of topical or
systemic steroids and immunosuppressives.
Epithelial keratitis
SYMPTOMS
Redness, pain
Photophobia
Lacrimation
Decreased vision.
SIGNS
Three distinct patterns of epithelial keratitis
1. Punctate epithelial keratitis: The initial epithelial lesions
resemble those seen in primary herpes and may be either in the
form of fine or coarse superficial punctate lesions.
2. Dendritic ulcer
? A typical lesion of recurrent epithelial keratitis.
? The ulcer has irregular, zigzag linear branching shape.
? The branches are general y knobbed at the ends.
? Floor of the ulcer stains with fluorescein and the virus-laden
cel s at the margin take up rose bengal.
? Corneal sensations is decreased
3. Geographical ulcer
? The branches of dendritic ulcer enlarge and coalesce
to form a large epithelial ulcer with a `geographical'
or `amoeboid' configuration
? The use of steroids in dendritic ulcer hastens the formation
of geographical ulcer.
PUNCTATE EPITHELIAL KERATITIS
DENDRITIC ULCER
GEOGRAPHIC ULCER
DISCIFORM KERATITIS
TREATMENT
SPECIFIC TREATMENT
1. Antiviral drugs are the first choice presently.
? Acycloguanosine (Aciclovir) 3% ointment, 5 times a day X 14?
21 days. It penetrates intact corneal epithelium and stroma,
achieving therapeutic levels in aqueous humour.
? Ganciclovir (0.15% gel), 5 times a day until ulcer heals and
then 3 times a day X 5 days.
? Triflurothymidine 1% drops: Two hourly until ulcer heals and
then 4 times a day X 5 days.
? Adenine arabinoside (Vidarabine) 3% ointment 5 times a day
until ulcer heals and then 3 times a day X 5 days.
2. Mechanical debridement of the involved area along with a
rim of surrounding healthy epithelium reserved for resistant
cases, cases with noncompliance and those al ergic to antiviral
drugs.
3. Systemic antiviral drugs- period of 10 to 21 days used for
recurrent and even acute cases.
? Acyclovir 400 mg p.o. tid to bid, or
? Famcyclovir 250 mg p.o. bid, or
? Valacyclovir 500 mg p.o.bid.
NON SPECIFIC TREATMENT
a. Cycloplegic drugs- 1% atropine eyeointment or drops
? To reduce pain from ciliary spasm
? To prevent the formation of posterior synechiae
? Atropine also increases the blood supply
? Reduce exudation by decreasing hyperaemia,
vascularpermeability.
? Other cycloplegic- 2% homatropine eye drops.
b. Systemic analgesics and anti-inflammatory drugs
such as paracetamol and ibuprofen relieve pain & decrease
oedema.
c. Vitamins (A, B-complex and C) help in early healing of ulcer.
Stromal keratitis
DISCIFORM KERATITIS
Pathogenesis
Due to delayed hypersensitivity reaction to the HSV antigen.
Endothelitis Endothelial damage disciform
corneal stromal oedema due to imbibition of aqueous humour.
Symptoms
v Photophobia
v Mild to moderate ocular discomfort
v Reduction in visual acuity.
Signs
Disciform keratitis is characterized by
v Focal disc-shaped patch of stromal oedema without necrosis,
usual y with an intact epithelium.
v Folds in Descemet's membrane.
v Keratic precipitates under the round area of stromal edema.
v Ring of stromal infiltrate (Wessley immune ring)
v Corneal sensations are diminished.
v Intraocular pressure (IOP) may be raised
Treatment
? Diluted steroid eye drops
? Instil ed 4?5 times a day with an antiviral cover (aciclovir 3%)
twice a day.
? Steroids should be tapered over a period of several weeks.
? If disciform keratitis is present with an infected epithelial
ulcer, antiviral drugs should be started 5?7 days before the
steroids.
? Non-specific and supportive treatment
Stromal necrotic keratitis
Interstitial keratitis
Active viral invasion and tissue destruction.
Symptoms: Pain, photophobia and redness
Signs
? Corneal lesions include necrotic, blotchy, cheesy white infiltrates
lie under the epithelial ulcer or present independently under the
intact epithelium.
? Mild iritis, keratic precipitates & Stromal vascularization
Treatment
Topical antiviral drugs, systemic antiviral drugs
keratoplasty
Metaherpetic keratitis
Epithelial sterile trophic ulceration is not an active viral disease,
but is a mechanical healing problem due to persistent defects in
the basement membrane of corneal epithelium.
Clinical features: It presents as an indolent linear or
ovoid epithelial defect. Margin of the ulcer is grey and
thickened due to heaped up epithelium.
Treatment is aimed to promote healing by use of
lubricants (artificial tears), bandage soft contact lens
and lid closure (tarsorrhaphy).
HERPES ZOSTER OPHTHALMICUS
? It is an acute infection of Gasserian ganglion of the fifth
cranial nerve by the varicel a-zoster virus (VZV).
? Approximately 10% of al cases of herpes zoster.
? Occurs more commonly in immunocompromised individuals.
Etiology
Varicella-zoster virus. It is a DNA virus and produces
acidophilic intranuclear inclusion bodies.
It is neurotropic in nature.
Pathogenesis
? The infection is contracted in childhood, which manifests as
chickenpox and the child develops immunity.
? The virus then remains dormant in the sensory ganglion of
trigeminal nerve.
? In immunocompromised patients, the virus reactivates,
replicates and travels down along branches of the
ophthalmic division of the fifth nerve to produce cutaneous
and ocular lesions.
Clinical Features
? Frontal nerve is more frequently affected than the lacrimal and
nasociliary nerves.
? Hutchinson's rule: ocular involvement is frequent if the side or
tip of nose presents vesicles (cutaneous involvement of
nasociliary nerve)
Lesions are strictly limited to one side of the midline of head.
Clinical phases
I. Acute phase lesions, total y resolve within few weeks.
II. Chronic phase lesions, which may persist for years.
III. Relapsing phase lesions, where acute or chronic
lesions reappear sometimes years later..
Acute phase lesions
General features: The onset of il ness is sudden with fever,
malaise and severe neuralgic pain along the course of the
affected nerve.
Cutaneous lesions: are in the area of distribution of the
involved nerve appear usual y after 3 to 4 days of the onset of
disease. The skin of lids and other affected areas become red
and oedematous (mimicking erysipelas), fol owed by vesicle
formation. vesicles are converted into pustules, subsequently
burst to become crusting ulcers. When crusts are shed,
permanent pitted scars are left. Active eruptive phase lasts for
about 3 weeks. Main symptom is severe neuralgic pain which
usual y diminishes with the subsidence of eruptive phase.
Cutaneous lesions of herpes zoster ophthalmicus
Ocular lesions
1.Conjunctivitis: It may occur as mucopurulent conjunctivitis
with petechial haemorrhages or acute fol icular conjunctivitis
with regional lymphadenopathy. Sometimes, severe
necrotizing membranous inflammation may be seen.
2. Zoster keratitis
? Epithelial keratitis. To begin with fine or coarse punctate
epithelial keratitis.
? microdendritic epithelial ulcers are usual y peripheral and
stel ate. They have tapered ends which lack bulbs.
? Nummularkeratitis: characterised by anterior stromal
infiltrates. It typical y occurs as multiple tiny granular
deposits surrounded by a halo of stromal haze. After healing
`nummular scars' are left behind.
? Disciform keratitis: always preceded by nummular keratitis.
3. Episcleritis and scleritis
4. Iridocyclitis
5. Acute retinal necrosis
6. Secondary glaucoma. It may occur due to trabeculitis or
synechial angle closure in late stages.
7. Anterior segment necrosis and phthisis bulbi
1. Punctate epithelial keratitis
2. Microdendritic epithelial ulcer
3. Nummular keratitis
4. Disciform keratitis
Chronic phase lesions
Sequelae of acute phase, may last for upto 10 years
1. Post-herpetic neuralgia refers to persistence of pain even
after subsidence of eruptive phase of zoster. Pain is mild to
moderate in intensity, worsens at night and is aggravated by
touch and heat.
There occurs some anaesthesia is cal ed anaesthesia dolorosa.
2. Lid lesions as sequelae of scarring include ptosis, trichiasis,
entropion and notching
3. Conjunctival lesions: chronic mucous secreting conjunctivitis
4. Corneal lesions
? Neuroparalytic ulceration due to acute infection and
Gasserian ganglion destruction.
? Exposure keratitis due to associated facial palsy.
? Mucous plaque keratitis characterised by sudden development
of elevated mucous plaque, stains with rosebengal.
5. Scleritis and Uveitis may persist in chronic form.
RELAPSING PHASE LESIONS
Lesions which may recur even after ten years of acute phase
include nummular keratitis, mucous plaque keratitis,
episcleritis, scleritis and secondary glaucoma.
TREATMENT
Systemic therapy for herpes zoster
1. Oral antiviral drugs. stop viral progression and reduce the
incidence as wel as severity of keratitis and iritis.
It has no effect on post herpetic neuralgia.
? Acyclovir - 800 mg, 5 times a day for 10 days
? Valaciclovir - 500 mg TDS.
2. Analgesics
combination of mephenamic acid and paracetamol /pentazocin
3. Systemic steroids. Reduce postherpetic neuralgia when
given in high doses. Recommended in cases of neurological
complications such as third nerve palsy and optic neuritis.
4. Cimetidine -300 mg QID for 2?3 weeks starting within 48?72
hours of onset reduse pain & pruritis by histamine blockade.
5. Amitriptyline relieve depression in acute phase.
LOCAL THERAPY FOR SKIN LESIONS
1. Antibiotic-corticosteroid skin ointment or lotions.
Three times a day til skin lesions heal.
2. No calamine lotion.
LOCAL THERAPY FOR OCULAR LESIONS
1. For zoster keratitis, iridocyclitis and scleritis
? Topical steroid eyedrops 4 times a day.
?Cyclopentolate eyedrops BD or atropine eye ointment OD.
? Topical acyclovir 3% eye ointment 5 times a day for 2 weeks.
2. To prevent secondary infections topical antibiotics are used.
3. For secondary glaucoma
? 0.5% timolol or 0.5% betaxolol drops, BD.
? Acetazolamide 250 mg, QID.
4. For mucous plaques, topical mucolytics e.g. acetyl cysteine
5 to 10%, three times a day.
5. For persistent epithelial defects use:
Lubricating artificial tear drops & bandage soft contact lens.
Surgical treatment
For neuroparalytic corneal ulcer caused by herpes zoster:
1. Lateral tarsorrhaphy should be performed.
2. Amniotic membrane transplantation (AMT) or conjunctival
flap for nonhealing cases.
3. Tissue adhesive with BCL for corneal perforation.
4. Keratoplasty. for visual rehabilitation of zoster patients with
dense scarring.
This post was last modified on 11 August 2021