​Kembara Xtra - Medicine - Herpes Eye Infections

​Kembara Xtra - Medicine - Herpes Eye Infections 
Eye infections brought on by the varicella-zoster virus (VZV, also known as human herpes virus type 3 [HHV3]) or herpes simplex virus (HSV) types 1 or 2 (blepharitis, conjunctivitis, keratitis, stromal keratitis, uveitis, retinitis, glaucoma, or optic neuritis).
- HSV: can cause primary and recurrent herpes keratoconjunctivitis, which most frequently damages the cornea.
-VZV: Herpes zoster ophthalmicus (HZO), a kind of shingles, is caused when VZV is reactivated and affects the ophthalmic division of the 5th cranial nerve.
Eye, skin, and newborn central nervous system (CNS) are the system(s) impacted.

Epidemiology 

HSV has a mean age of onset of 37.4 years but can cause primary infection in infants; VZV typically affects those who are older (>50 years).
Incidence
HSV keratitis is thought to affect 18.2 people per 100,000 people-years in the US. There are 1.5 million cases worldwide each year.

VZV: In the US, there are 1 million new cases of shingles every year; 25–40% of these instances result in ocular problems. The most frequent keratitis is temporary.
Prevalence
According to estimates, 500,000 Americans have ocular HSV.
VZV: 20–30% of people will contract herpes zoster.
If antivirals are not used, 50% of cases of ocular involvement will occur (2); the lifetime frequency of HZO is 1%.

Pathophysiology and Etiology 
HSV and VZV are herpesviruses with dsDNA.
HSV: a primary infection brought on by close contact with an infected person, such as by saliva, genital touch, or birth canal exposure (in neonates).
- Severe disease in newborns, such as eye, skin, CNS, and widespread disease, may result from primary infection. Herpetic eye infections are generally caused more frequently by recurrent infection.
VZV: A primary infection brought on by close contact with an infected person may result in varicella (also known as chickenpox) or induce a latent state to develop inside the trigeminal ganglia.
– Any dermatome, including the ophthalmic branch (HZO), could be affected by the virus reactivating, resulting in "shingles" or herpes zoster.

Personal history of HSV or close contact with an HSV-infected individual are risk factors for the virus, as are stress, trauma, fever, exposure to UV light, and other viral diseases.
- Some topical ocular medicines, such as prostaglandin analogues, and primary/secondary immunosuppression are risk factors for HSV keratitis.

Age (>50 years), sex preference for women over men, an acute or painful prodrome, trauma, stress, and immunosuppression are all associated with HZO.

Alert

Consider primary/secondary immunodeficiency diseases (such as AIDS and cancer) in all zoster patients under the age of 40.

Prevention 
VZV can infect people who haven't had chickenpox, haven't been inoculated against it, or who aren't immune. Contact precautions with active lesions (HSV and VZV).
Recombinant varicella-zoster vaccine (Shingrix) (VZV only): The CDC advises two doses given two to six months apart for everyone over the age of 50. Shingrix, which is no longer available in the United States, is favored over an older vaccination called Zostavax, which can still be used for people over 60 who are unable to take it. (4)
- Avoid administering the varicella vaccine when sick.
Acyclovir can be taken as a preventative measure to stop the recurrence of ocular HSV.
HSV vaccination is currently being studied

It is not recommended to get vaccinated against zoster using live vaccine (Zostavax) if you have HIV or any immunocompromising condition, are pregnant, or have active, untreated tuberculosis (TB).

pregnant women's issues
Women who are pregnant and have never had the chickenpox should stay away from people who have active zoster.
The HSV/VZV recurrence risk increases during pregnancy, and both the Shingrix and Zostavax vaccines should be avoided.


Accompanying Conditions 
conditions of both primary and secondary immunosuppression


Presenting History Varies depending on the virus and the affected ocular structures History of varicella or herpes simplex infection Acute onset, eye pain, headache, photophobia, tearing, ocular redness, decreased or blurred vision May present with a prodromal period of fever, malaise, headache, and eye pain prior to skin eruptions and eye lesions (HZO)

clinical assessment 
Varies depending on the virus and the affected ocular structures; HSV most frequently damages the corneal epithelium. VZV most frequently affects the uvea and corneal stroma.

HZO typically manifests unilaterally and can do so as soon as 1 to 2 days following a single vesicular eruption in a dermatomal pattern.

Reduced corneal sensitivity, decreased corneal sensibility, decreased visual acuity, conjunctival injection near the limbus, and a dendritic pattern visible with conjunctival florescence staining

Alert 

Most frequently occurring in the ophthalmic branch (V1) of the trigeminal nerve (VZV) is unilateral dermatomal vesicular rash:
Hutchinson sign: The involvement of the nasociliary branch of the trigeminal nerve, which also innervates the eye, in a vesicular lesion on the nose caused by VZV implies an elevated risk of HZO.


Multiple Diagnoses 

 Any other ailment that results in red, stinging eyes, including bacterial, fungal, allergic, or viral conjunctivitis
- Glaucoma with acute angle-closure
Temporal arteritis; trigeminal neuralgia; corneal abrasion; recurrent corneal erosion; toxic conjunctivitis

Laboratory Results 

Initial examinations (lab, imaging)
Usually none are necessary because the diagnosis is based on the history and physical examination.
Polymerase chain reaction (PCR) testing of a corneal swab for HSV DNA (PPV = 96%)

 A Tzanck smear for VZV or HSV (multinucleated giant cells) can be done if a vesicle is present.

Direct fluorescent antibody (DFA), tissue culture, and antibody titers to measure merely exposure
ALERT
For a slit-lamp examination, a dilated fundus examination, and an intraocular pressure measurement, an urgent ophthalmology referral is required.

Avoid interacting with non-immune people.
Wearing contact lenses is not advised while receiving therapy.
Cold compresses; artificial tears; and painkillers taken by mouth

First Line of Medicine
corneal epithelial disease caused by HSV
- Trifluridine 1%: Use 1 drop every two hours (q2h) while awake up to a total of nine drops per day until reepithelialization takes place, then 1 drop every four hours for an additional seven days.
- 400 mg PO five times daily for ten days of acyclovir.
- Ganciclovir: 0.15% gel: Apply 1 drop in the eye every three hours while awake, five times daily, until reepithelialization takes place, and thereafter 1 drop every eight hours for seven days.
About 90% of treated eyes are cured by trifluridine and acyclovir within two weeks, with no discernible changes in efficacy.
- Conflicting evidence regarding whether ganciclovir is superior to or equal to acyclovir.
- When combined with the aforementioned treatments, epithelial débridement performed by an ophthalmologist may hasten healing (5).[A]
Prevent using topical steroids.
HSV stromal keratitis or uveitis (without epithelial disease): combination of antiviral and steroid treatment; requires ophthalmology examination. Utility of PO antivirals unknown
1% drops QID of prednisolone acetate with a steady taper- When treating severe uveitis, consider systemic steroids.
- Trifluorothymidine: 1% drops three times daily for prevention when using topical steroids
HZO: Valacyclovir (Valtrex), 1 g PO TID for 7–10 days; famciclovir (Famvir), 500 mg PO TID for 7–10 days; or acyclovir, 800 mg PO 5 times daily for 7–10 days
- When compared to acyclovir, valacyclovir and famciclovir significantly reduce PHN (number needed to treat [NNT] = 3 with equal efficacy).
– Ocular surface protection with topical antibiotic ophthalmic ointment (e.g., polymyxin B, bacitracin): Acyclovir 10 to 15 mg/kg IV every eight hours for 10 days if immunocompromised. Prednisolone acetate: 1% drops QID with moderate taper under the supervision of an ophthalmologist.
Cycloplegic medication if anterior uveitis is present; if required, an intraocular pressure-lowering medication

Acyclovir 2 g/day PO in divided dosages over 10 days is the second line treatment for HSV in patients who are intolerant to topical antivirals.
The use of topical idoxuridine, acyclovir, and brivudine is permitted abroad but not in the United States. Concomitant interferon therapy may also enhance outcomes but is not yet available.

HZO warning: Although antiviral therapy is most effective when started within the first 72 hours of rash onset, it should still be started more than 72 hours later due to the possibility of complications from HZO.

Topical steroids should only be prescribed in collaboration with an ophthalmologist. Topical antiviral drugs are toxic to the corneal epithelium, especially after 10 to 14 days of continuous usage. When corneal epithelial disease is active, a slit lamp should be used for monitoring.
– can induce cataracts with prolonged usage, corneal thinning, and a rise in intraocular pressure.
Immunocompromised people should use Prednisone with caution.

Referral 

Depending on the severity of the ailment, ophthalmology referrals may be urgent or urgent.

Further Treatments 

HZO leading to PHN is prevalent and can be treated with gabapentin or pregabalin, TCAs, opioids, and/or lidocaine gel. Recurrent HSV necessitates suppressive medication.

Surgical Techniques 

transplantation of the cornea in cases of extensive scarring or perforation

Systemic HSV in newborns and severe systemic VZV illness upon admission

Patient Follow-Up Monitoring
Slit-lamp exams should be used to check for improvements every 1-2 days, and subsequently every 3–4 days until the epithelial defect is fixed.
Weekly until topical antivirals are stopped once epithelial disease resolves

Inform people about the significance of early detection of recurrent symptoms and the necessity for timely assessment and treatment.

Prognosis: Although many cases are self-limited, some can result in permanent blindness depending on the ocular structure implicated, particularly when the disease is recurring.
The leading infectious cause of blindness worldwide is ocular HSV.
Recurrent ocular HSV - HSV epithelial illness without treatment - 40% resolve without sequelae - With treatment, 90-95% resolve uncomplicated.

Child Safety Considerations
High mortality rate for neonatal primary HSV; 37% of children have eyesight poorer than 20/200.

Pediatric instances have a higher likelihood of being bilateral (26%), recurrent (48% after 15 months), and amblyopia-causing (12%).

Recurrence; Corneal neovascularization and scarring that impair vision; Neurotrophic ulcer with perforation; Secondary bacterial or fungal infection; Secondary glaucoma; PHN in 20–40% with VZV; Vision loss from optic neuritis or chorioretinitis; PHN in 20–40% with VZV, usually lasting longer in older patients

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