HSK Flashcards

1
Q

Where does HSV go to establish latency?

A

The Trigeminal ganglion

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2
Q

What 3 branches does the trigeminal ganglion branch out to?

A
  • Ophthalmic (eyes)
  • Maxillary
  • Mandibular (mouth)
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3
Q

What are LATs?

A

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

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4
Q

What is Corneal Hypoesthesia?

A

Decreased corneal sensitivity

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5
Q

What can trigger HSK reactivation?

A
Fever
Cold
URT Infection
UV exposure
Fatigue
Menstruation 
Stress
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6
Q

What are the Symptoms of Primary Infection of Herpes Simplex?

A
  • 65% show no signs/symptoms
  • symptoms usually are similar to any other viral infection
  • Acute conjunctivitis (lasts <2 weeks)
  • SPK
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7
Q

What are the classifications of HSV Keratitis?

A
  • Epithelial Keratitis (Dendritic epithelial ulcer or Geographic epithelial ulcer
  • Stromal Keratitis With/Without Ulceration (Non-nectrotixing, Interstitual, immune stromal keratitis)
  • Endothelial Keratitis (Disciform Keratitis)
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8
Q

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

A

Symptoms

  • Unilateral Redness
  • Watery DIscharge
  • Photophobia
  • Irritation

Signs (in order of progression)

  • Raised epithelial lesion
  • SPK
  • Dendritic Ulcer
  • Geographic Ulcer
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9
Q

What is the Treatment of HSV Epithelial Keratitis?

A

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.

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10
Q

What is the review plan for HSV Epithelial Keratitis?

A
  • 24-48 Review
  • Then every 2-3 days up to 14 days.
  • If healing isnt seen, reconsider diagnosis, maybe medication toxicity
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11
Q

What is the prescribed dosage for oral aciclovir?

A
400mg po (orally)  q5h for 7-10 days
HEDS study has found both oral and topical treatment to be of equal efficacy.
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12
Q

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

A

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

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13
Q

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

A

Active

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

Inactive

  • Stromal Scars
  • Stromal thinning
  • Ghost Vessels
  • KP
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14
Q

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

A

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.

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15
Q

What are some triggers for HSV keratitis?

A

Conditions that reduce immune systems efficacy

immunoCOMPROMISED

  • Organ transplant
  • Diabetes mellitus
  • Measels
  • HIV

ImmunoDEPRESSION

  • Fever
  • Stress
  • Menstruation
  • Severe weather events
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16
Q

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

A
  • Gender
  • Age
  • Ethnicity
  • History of Non Ocular HS disease
  • Contact Lens Wear (no association seen contact lens wear and HSV keratitis recurrence)
17
Q

What are some Ocular Triggers for HSV keratitis?

A

Increase susceptibility

  • Prostaglandin Analogues
  • Corticosteroids
  • Angiogenesis Inhibitors

Local Trauma and Inflammation

  • Laser refractive surgery
  • Cataract Surgery
  • Ocular Steroids
18
Q

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

A

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

19
Q

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

A

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