HSK

Question 1

Where does HSV go to establish latency?

Answer 1

The Trigeminal ganglion

Question 2

What 3 branches does the trigeminal ganglion branch out to?

Answer 2

• Ophthalmic (eyes)
• Maxillary
• Mandibular (mouth)

Question 3

What are LATs?

Answer 3

Latency Associated Transcripts
- LATs facilitate latency through repression of infected cell polypeptide 0 (ICP0) which dismantles normal cell transcription/translation and promotes viral replication.

-LATs also promote neuronal survival by blocking apoptosis, so infected neurons survive

Question 4

What is Corneal Hypoesthesia?

Answer 4

Decreased corneal sensitivity

Question 5

What can trigger HSK reactivation?

Answer 5

Fever
Cold
URT Infection
UV exposure
Fatigue
Menstruation 
Stress

Question 6

What are the Symptoms of Primary Infection of Herpes Simplex?

Answer 6

• 65% show no signs/symptoms
• symptoms usually are similar to any other viral infection
• Acute conjunctivitis (lasts <2 weeks)
• SPK

Question 7

What are the classifications of HSV Keratitis?

Answer 7

• Epithelial Keratitis (Dendritic epithelial ulcer or Geographic epithelial ulcer
• Stromal Keratitis With/Without Ulceration (Non-nectrotixing, Interstitual, immune stromal keratitis)
• Endothelial Keratitis (Disciform Keratitis)

Question 8

What are the common signs/symptoms of HSV Epithelial Keratitis?

Answer 8

Symptoms

• Unilateral Redness
• Watery DIscharge
• Photophobia
• Irritation

Signs (in order of progression)

• Raised epithelial lesion
• SPK
• Dendritic Ulcer
• Geographic Ulcer

Question 9

What is the Treatment of HSV Epithelial Keratitis?

Answer 9

No treatment

• 1st Ophthalmic occurrence the resolution is in about 17 days
• If recurrent resolution in about 28 days.

Treatment
- Anti-viral, Aciclovir 3% ointment q5h for 14 days, however treatment should continue for 3 days after healing.

Question 10

What is the review plan for HSV Epithelial Keratitis?

Answer 10

• 24-48 Review
• Then every 2-3 days up to 14 days.
• If healing isnt seen, reconsider diagnosis, maybe medication toxicity

Question 11

What is the prescribed dosage for oral aciclovir?

Answer 11

400mg po (orally)  q5h for 7-10 days
HEDS study has found both oral and topical treatment to be of equal efficacy.

Question 12

Why should you never use a steroid on an active HSV ucler?

Answer 12

It promotes deeper HSV infection, helping epithelial level keratitis become stromal level keratitis.

Question 13

How can you tell the difference between active and inactive stromal keratitis?

Answer 13

Active

• stromal inflammation with infiltration
• oedema
• vascularisation
• AC reaction

Inactive

• Stromal Scars
• Stromal thinning
• Ghost Vessels
• KP

Question 14

What causes the Stromal Inflammation in HSV stromal keratitis without ulceration?

Answer 14

TYPE III Antibody-Antibody Hypersensitivity Reaction, which leasds to immune precipitation in the stroma and a Diffuse inflammatory Wessely Ring infiltrate

TYPE IV Cell Mediated Hypersensitvity reaction where the T lymphocytes respond to the Antigen in the stroma, and this takes up to a couple days to happen.

Question 15

What are some triggers for HSV keratitis?

Answer 15

Conditions that reduce immune systems efficacy

immunoCOMPROMISED

• Organ transplant
• Diabetes mellitus
• Measels
• HIV

ImmunoDEPRESSION

• Fever
• Stress
• Menstruation
• Severe weather events

Question 16

What has the HEDs study stated as NON triggers for HSV keratitis?

Answer 16

• Gender
• Age
• Ethnicity
• History of Non Ocular HS disease
• Contact Lens Wear (no association seen contact lens wear and HSV keratitis recurrence)

Question 17

What are some Ocular Triggers for HSV keratitis?

Answer 17

Increase susceptibility

• Prostaglandin Analogues
• Corticosteroids
• Angiogenesis Inhibitors

Local Trauma and Inflammation

• Laser refractive surgery
• Cataract Surgery
• Ocular Steroids

Question 18

What is the efficacy of short term high dose acyclovir for the recurrence of HSV keratitis according to the HEDs study?

Answer 18

400mg acyclivor orally twice a day has shown a 50% less reoccurance in the treated group vs control group.

Question 19

What is the treatment for stromal keratitis is there is an epithelial defect seen?

Answer 19

Use anti-viral (aciclovir q5h) BEFORE steroid treatment is started for stromal disease.

When Ucler is healed taper with prophylactic dose (over week) in conjunction with steroid