29. Viral Anterior Eye Conditions

Question 1

What is the most common infective cause of blindness in developed countries?

Answer 1

Herpes simplex virus

Question 2

There are 8 types of viruses in the Herpesviridae family: ..., ..., ..., ... (...), Human Herpes Virus type 6 (HHV6), Human Herpes Virus type 7 (HHV7), ...-... (...) and Human Herpes Virus type 8 (HHV8). HSV infection is common, where ...% of people age 4 are ... for HSV and ...% of people age 60 are ... for HSV. Approximately 1% of HSV-infected people develop ... manifestations during their lifetime. Viruses that can cause herpetic keratitis are ..., ... and ..., where ... causes the most ocular lesions.

Answer 2

There are 8 types of viruses in the Herpesviridae family: HSV 1, HSV 2, VZV, Cytomegalovirus (CMV), Human Herpes Virus type 6 (HHV6), Human Herpes Virus type 7 (HHV7), Esptein-Barr virus (EBV) and Human Herpes Virus type 8 (HHV8). HSV infection is common, where 25% of people age 4 are seropositive for HSV and 100% of people age 60 are seropositive for HSV. Approximately 1% of HSV-infected people develop ocular manifestations during their lifetime. Viruses that can cause herpetic keratitis are HSV 1, HSV 2 and VZV, where HSV 1 causes the most ocular lesions.

Question 3

Conditions where we should target inflammation:
* ...
* CL-related ...
* ... conjunctivitis
* ... disease
* Dry eye
* ...
* ...
* ...
* ... conjunctivitis
* ... keratitis
* Ocular ... conditions
* ...
* Recurrent ...

Answer 3

Conditions where we should target inflammation:
* Infiltrate
* CL-related recurrent erosion
* Giant papillary conjunctivitis
* Lid wiper disease
* Dry eye
* Allergy
* Episcleritis
* Uveitis
* Viral conjunctivitis
* Marginal keratitis
* Ocular surface conditions
* Trauma
* Recurrent erosion

Question 4

Conditions where we should target infection:
* ... keratitis
* ... infection
* ... infection
* ... cellulitis
* ... infections - ... conjunctivitis./ ...
* ... conjunctivitis
* ` …` keratitis

Answer 4

Conditions where we should target infection:
* Microbial keratitis
* Lid infection
* Lacrimal infection
* Preseptal cellulitis
* Adenoviral infections - adenoviral conjunctivitis./ keratoconjunctivitis
* Bacterial conjunctivitis
* Herpes simplex keratitis

Question 5

Herpes simplex keratitis gives a ... lesion and it could present with .... This lesion stains to ... and .... ... + blue light stains the epithelial defects, whereas ... + white light stains for the dead and devitalised cells. Px with HSK may also have decreased ....

Answer 5

Herpes simplex keratitis gives a branch-like lesion and it could present with end bulbs. This lesion stains to fluorescein and Lissamine green. NaCl + blue light stains the epithelial defects, whereas Lissamine green + white light stains for the dead and devitalised cells. Px with HSK may also have decreased corneal sensitivity.

Question 6

HSV-1 is usually found in ... or ... regions and they make up of ...% of ocular isolates. HSV-2 is usually found in ... regions and make up of ...% of ocular isolates. However, ... accounts for approximately 80% of neonatal ocular herpes as infants may have incoulated their eyes via contact with ... or via the .... HSV is spread by ... of ... or ... with infectious secretions. Around ...-...% of adults have antibodies to HSV-1.

Answer 6

HSV-1 is usually found in orofacial or ocular regions and they make up of 85% of ocular isolates. HSV-2 is usually found in genital regions and make up of 15% of ocular isolates. However, HSV-2 accounts for approximately 80% of neonatal ocular herpes as infants may have incoulated their eyes via contact with infected secretions or via the birth canal. HSV is spread by direct contact of epidermis or mucous membranes with infectious secretions. Around 50-99% of adults have antibodies to HSV-1.

Question 7

How common are HSV infections? Why are they often not noticed?

Answer 7

70% humans infected by 15-25 yo;
>90% humans infected by 60 yo. Only 11% of cases presents as bilateral infection. This is often unoticed as most infections are subclinical in 99% of cases.

Question 8

HSV spreads from ... site of infection to .... They are transported down nerve axon to ... in a .... Virus genome can enter the ... where it persists in a .... Primary infection of any branch of ... can result in ... without ever having had ....

Answer 8

HSV spreads from epithelial site of infection to sensory nerve ending. They are transported down nerve axon to cell body in a sensory ganglion. Virus genome can enter the nucleus of neurone where it persists in a latent state. Primary infection of any branch of CNV can result in recurrent HSV without ever having had primary ocular HSV.

Question 9

The only topical antiviral available aginst HSV and VZV is .... It is an analog of ... and is activated by virally expressed .... It disrupts ... and it very potent only to ..., therefore it has a great .... Topical ... is useful for ..., prophylaxis, during management of herpes simplex related ..., ... and ... uveal disease. It is sometimes used as an adjust in .... Oral ... can also be used as ... against recurrent ... and ....

Answer 9

The only topical antiviral available aginst HSV and VZV is acyclovir/ aciclovir. It is an analog of guanosine and is activated by virally expressed thymidine kinase. It disrupts viral DNA replication and it very potent only to virus-infected cells, therefore it has a great safety profile. Topical aciclovir is useful for epithelial HSK, prophylaxis, during management of herpes simplex related stromal, endothelial and anterior uveal disease. It is sometimes used as an adjust in HZO-related keratitis. Oral aciclovir can also be used as prophylaxis against recurrent HSK and herpes zoster ophthalmicus.

Question 10

What is the concentration of aciclovir in ointment form? How are they used and what are the precautions?

Answer 10

3% aciclovir ointment. 1cm of ointment in lower cul-de-sac 5 times a day for 14 days or for 3 days after corneal epithelium healed. There may be a mild stinging with use. It is safe in children, pregnancy and breastfeeding.

Question 11

What is the advise given to px who have recurrent HSK?

Answer 11

Advise px to keep a spare unopened tube of aciclovir ointment and start treatment at the first sign of recurrence.

Question 12

How should a swab be done for HSK?

Answer 12

Roll swab around the lesion to pick up the virus. Don’t wait until results, must treat based on clincial signs and straight away. Lab PCR tests tend to take a while.

Question 13

What are the presentations of primary ocular herpes?

Answer 13

• Unilateral or bilateral facial and or eye infection
• Fever, flu liike symptoms
• Follicular conjunctivitis
• Vesicular blepharoconjunctivitis
• Positive preauricular node swelling and tenderness
• possible corneal involvement - SPK, dendrites; but without stromal involvement

Question 14

Treatments for the following HSV related conditions:
* Blepharoconjunctivitis
* Corneal SPK
* Corneal dendrites
* Skin lesions

Answer 14

Treatments for the following HSV related conditions:
* Blepharoconjunctivitis - aciclovir 3% ointment 5 times a day
* Corneal SPK - lubricants
* Corneal dendrites - topical aciclovir
* Skin lesions - topical antibodies (chlorsig ointment)

Question 15

What are the 5 different forms of recurrent ocular herpes simplex?

Answer 15

• Infectious epithelial keratitis
• Non-necrotising stromal keratitis (disciform)
• Necrotising stromal keratitis
• Neurotrophic keratitis
• Keratouveitis

Question 16

What are the treatments of HSK?

Answer 16

• Epithelial debridement → lifting off lots of viruses off the lesion by rolling a cotton bud over and over
• Aciclovir ointment 5 times a day for 14 days or for 3 days after corneal epithelium is healed

Question 17

What should be considered to aciclovir treatment does not work for HSK?

Answer 17

• Px poor compliance
• Resistance to anti-viral therapy
• Antiviral toxicity
• Neurotrophic disease

Question 18

What should you do if you encounter a geographic ulcer instead of a dendritic ulcer with HSK?

Answer 18

Refer to Eye & Ear hospital. But if rural, optom will need to handle this using both topical and oral Rx.

Question 19

How should non-necrotising stromal keratitis (disciform) be managed?

Answer 19

• Topical steroids e.g. prednisolone 1% QID + aciclovir ointment 5 times a day or oral aciclovir 400mg 5 times a day
• Need to carefully and slowly taper steroids from weeks to months (the longer the steroid therapy, the longer the tapering is needed)
• May need to add antibiotics QID e.g. flarex, ciprofloxacin, olofloxacin → Antiviral + Steroids + Antibiotics

Question 20

Necrotising stromal keratitis is rare and is caused by ... and ... of corneal stroma. It is associated with ... defects. Optom should rule out ... or ... infections. Treatment involves ... and .... May have to treat associated ....

Answer 20

Necrotising stromal keratitis is rare and is caused by viral infiltration and inflammation of corneal stroma. It is associated with epithelial defects. Optom should rule out bacterial or fungal infections. Treatment involves topical steroids and systemic antivirals. May have to treat associated uveitis.

Question 21

Herpes zoster ophthalmicus is an infection caused by the ... (...) in the ... that has migrated down along the ..., therefore affect the skin of the .... If the ... division (...) of the ... nerve CN5 is involved, the conditions is called HZO. This is more common and severe in ... and .... This is also known as ... when present dermatologically. The mean age of VZV reactivation is ... years old. HZO result in chronic eye disease, various forms of keratitis: ..., ..., ..., uveitis and .... ... sign arises due to the involvement of the ... branch of the ... nerve and is highly predictive of eye involvment.

Answer 21

Herpes zoster ophthalmicus is an infection caused by the reactivation of chicken pox virus (VZV) in the dorsal root ganglion that has migrated down along the sensory nerves, therefore affect the skin of the particular dermatome. If the ophthalmic division (V1) of the trigeminal nerve CN5 is involved, the conditions is called HZO. This is more common and severe in immunocompromised and elderly. This is also known as shingles when present dermatologically. The mean age of VZV reactivation is 52 years old. HZO result in chronic eye disease, various forms of keratitis: dendriform keratitis, stromal keratitis, endothelial keratitis, uveitis and neurotrophic keratopathy. Hutchinson's sign arises due to the involvement of the nasocillary branch of the trigeminal nerve and is highly predictive of eye involvment.

Question 22

What is post herpetic neuralgia (PHN)? What are the impact of PHN?

Answer 22

Intense dermatomoal pain and/ or itch beyond 3 months associated with shingles. Hugely impact quality of life and is a risk factor of major depression. Increase risk of stroke, CVD and giant cell arteritis.

Question 23

What are the treatments for shingles and PHN?

Answer 23

• Antiviral or antibacterial ointment on vesicles/ sores on skin
• Cool compresses
• Lubricants
• Antidepressants (TCAs) or gabapentin → work on pain

Question 24

What is Shingrix?

Answer 24

A non-live, recombinant subunit vaccine given intramuscularlly in two doses to px susceptible to shingles (~52yo). It has been found to decreased VZV incidence and post-herpetic neuragia. However it may not be cost effective. (Still new)