Herpes Simplex Keratitis Case Record

Patient: DM

Age: 56

Sex: Male

Initial visit date: 18^th September 2018

History and symptoms – initial visit

Patient initially triaged as referred by local pharmacist and advised same day appointment (appendix A).

Patient is new to practice. Unsure when or where last test was.

Patient reports a generally uncomfortable right eye, slight foreign body sensation, little pain, watery with minimal photophobia. Duration two days. Vision is a little blurred due to the watering but otherwise feels its fine. Left eye is normal.

POH: Two previous episodes of herpes simplex keratitis affecting right eye only, both 2016. Treated at Ninewells Hospital, Dundee. No contact lens worn. Uses reading spectacles only. No other previous problems reported.

PGH: Good health and no medication currently taken. However, patient mentions that he had stopped taking an antiviral medication around four months ago which was prescribed following his second episode of herpes simplex keratitis (HSK). His reason for stopping was that he was increasingly forgetting to take it.

PFH: no diabetes, no glaucoma, no ocular problems apart from cataract with both parents.

Occupation: Office manager (vdu use 6/24)

Lifestyle: gardening

Clinical findings – initial visit

Vision R 6/6-2 (Pinhole 6/5) L 6/5

Pupils: PERRLA, no RAPD, no discomfort reported.

IOPs: R 17mmHg L 16mmHg, Tonoref 3, 11:20am (post dilation R 16mmHg L16mmHg, Tonoref 3, 12:15pm)

Non-contact pachymetry: R 557µm L 552 µm, Tonoref 3

Slit lamp examination

Corneal sensation assessed. A cotton bud (one for each eye) was used to compare sensation with each eye especially the quadrant with the ulcer. Patient reported reduced sensitivity with the quadrant that had the ulcer compared to the contralateral quadrant of the left eye.

Dilated fundus examination

Minims Tropicamide 1.0% BN H3251N EXP 06/2019 1gtt OU

Diagnosis

Recurrent herpes simplex epithelial keratitis (Due to dendritic ulcer with end bulbs, reduced corneal sensitivity and previous history affecting same eye).

Differential diagnosis

Acanthamoeba keratitis (highly unlikely as does not wear contact lenses).

Fungal keratitis (possible as similar symptoms and the patient is a keen gardener however the dendritic ulcer, previous history of HSK and reports mild foreign body sensation suggests it’s not).

Bacterial keratitis (possible as patient is a keen gardener however minimal pain reported, mild foreign body sensation, dendritic ulcer present and previous history of HSK)

Herpes zoster ophthalmicus (unlikely as no evidence of skin rash or lesions and negative Hutchinson’s sign).

Healing corneal erosion/abrasion (possible as he enjoys gardening – risk of abrasion and foreign body; does spend several hours looking at a VDU – possible dry eye syndrome and superficial punctate keratopathy).

Management

The clinical findings were reported back with the diagnosis. The patient expected this. As it was the third episode, no stromal involvement, no evidence of viral retinitis and the patient does not wear contact lenses I decided to prescribe acyclovir 3% eye ointment (appendix B). The patient was advised to use it five times a day ideally with four-hour intervals whilst awake. The patient was instructed to pull the lower lid down and place approximately a one-centimetre ribbon of the ointment within exposed conjunctival sac.

As the patient had minimal pain, he declined the option of cyclopentolate 1.0% for any ciliary body spasm.

The patient was advised to return in four days for follow up. He was advised any negative changes to vision, pain, photophobia or appearance of eye to return immediately or contact NHS24 if out of hours. Due to contagious nature of the virus advice was provided on hygiene.

The patient was also offered same day referral to HES as per NICE guidelines for HSK (NICE, 2016) however patient declined. The patient’s GP was informed of diagnosis and management plan (appendix C).

Four-day follow-up 22^nd September 2018

Patient reports significant improvement. He describes his right eye as feeling almost normal. Left eye still normal.

Vision R 6/6 (Pinhole 6/5) L 6/5

Pupils: PERRLA, no RAPD, no discomfort reported.

IOPs: R 16mmHg L 16mmHg, Tonoref 3, 10:30

Non-contact pachymetry: R 554µm L 553 µm, Tonoref 3

Advised the patient that the management plan was working. The eye was healing well. Advised continue with the acyclovir 3% as initially indicated for a further seven days. Advised review in seven days. Reiterated the advice on any negative changes and to seek help either with myself or NHS24 if out of hours.

Eleven-day follow-up 29^th September 2018

Patient reports right eye feels like left eye.

Vision R 6/6 (Pinhole 6/5) L 6/5

Pupils: PERRLA, no RAPD, no discomfort reported.

IOPs: R 16mmHg L 16mmHg, Tonoref 3, 15:40

Non-contact pachymetry: R 555µm L 552 µm, Tonoref 3

Because cornea has healed, continue with acyclovir 3% five times a day for three days then stop (BNF, 2019). Discussed with patient that if he has another episode within twelve months it will be recommended to restart oral acyclovir 400mg twice daily for twelve months (BNF, 2019). The patient’s GP was advised on the outcome (see appendix D). I advised that this episode may have been triggered by fatigue or stress and to reflect on any changes that can be made with work if that’s a source of stress. I also advised strong UV exposure can be another risk factor and emphasised the importance of good fitting sunglasses especially as he enjoys his gardening.

Discussion

The patient’s presenting symptoms of a generally uncomfortable eye with little pain, mild foreign body sensation, watering are typical of herpes simplex keratitis (Bruce & Loughnan, 2003; Kanski, 2003).

Two specific investigations were carried out that are not normally indicated with other forms of keratitis as described within The College of Optometrists clinical management guidelines (THE COLLEGE OF OPTOMETRISTS, 2018a; THE COLLEGE OF OPTOMETRISTS, 2018b; THE COLLEGE OF OPTOMETRISTS, 2018c; THE COLLEGE OF OPTOMETRISTS, 2017a). They were pupil dilatation and corneal sensitivity assessment. The primary reason for pupil dilatation is to rule out viral retinitis as if present would require a same day referral to hospital eye service (HES) (THE COLLEGE OF OPTOMETRISTS, 2018d). Using a cotton bud is a basic method of assessing corneal sensitivity however can aid the optometrist with the diagnosis. The virus can cause nerve damage within epithelium, sub epithelium and stroma resulting in reduction in sensitivity (Chucair-Elliott et al, 2015). Zemaitiene et al (2019) have demonstrated that the HSK affected eye has significant reduction of corneal sensitivity compared to the contralateral eye.

I decided to manage this patient within a primary setting as HSK is primarily diagnosed on clinical signs. I was confident that there was only epithelium involvement as there was no evidence of stromal oedema. His posterior eye had been assessed for viral activity and demonstrated none. He had two previous episodes with the same eye within twelve months and was given a prophylactic oral antiviral medication; this indicates this was a recurrent episode. If there had been any involvement of the stroma or endothelium, he would have been referred to the HES for same day management. Same day referral would have also been provided if there was evidence of viral retinitis even if the HSK was only affecting the epithelium. This is recommended by The College of Optometrists clinical management guidelines (The College of Optometrists, 2018d).

Topical acyclovir 3% ointment is indicated for the treatment of HSK (BNF, 2019). This is also first choice treatment on the NHS Tayside formulary (NHS Tayside, 2019). Contraindication is previous hypersensitivity to the ointment which was not reported with previous cases. Its not advised to use the ointment with contact lens wear, the patient does not wear contact lenses. Side effects can be stinging and blurring of vision following application. There is a possibility of developing a hypersensitivity to it or one its ingredients (The College of Optometrists, 2018e). I considered the alternative, Ganciclovir 0.15% eye gel, although its only available for use if the patient is resistant to acyclovir 3% ointment. According to Christophers et al (1998), prevalence is low at 0.1% to 0.6% in immunocompetent individuals resistant to the antiviral. Therefore, I am unlikely to come across an individual who is resistant to acyclovir.

The patient was keen to be managed within the community as it fitted his lifestyle better and the practice is convenient to get to and open seven days a week. This was the reasoning why he declined the offer of referral based on NICE guidelines (NICE, 2016). The gentleman was happy to proceed with a pharmaceutical management plan but only wanted what was necessary to heal the ulcer. Therefore, he declined the offer of cyclopentolate to alleviate any pain as he felt his pain was low and was coping with it; he did not like the dilated pupil from previous episodes too. He expected topical antivirals to aid the healing process which would help with pain based on previous experience.

I feel that I provided an effective management plan to the patient. However, I feel there was an issue around consent. If I was to manage a similar situation again I would obtain written consent and provide more information (The College of Optometrists, 2017b) due to the potential sight threatening risks involved with HSK as to allow the patient to make a more informed decision regarding management within the community or to be referred to HES. For example, HSK is the leading cause of corneal blindness in the developed world. In the UK, its responsible for one in 10 corneal transplants (The College of Optometrists, 2018d). Also, a study found that 3% of herpes simplex virus epithelial keratitis cases resulted in vision less 6/60 (Wilhelmus et al, 1981 cited in Farooq & Shukula, 2012).

Key

POH  patient’s ocular history

PGH  patient’s general health

PFH  patient’s family history

HSK  herpes simplex keratitis

PERRLA  pupils equal & round and react to light & accommodation

RAPD  relative afferent pupillary defect

NaFl  Sodium Fluorescein

VH4  Van Herick grade 4

BN  batch number

EXP  expiry

1gtt  one drop

OU  both eyes

VDU  visual display unit

HES  hospital eye service

NHS24  National Health Service twenty-four hours a day advice service

NHS   National Health Service

GP   General Practitioner

References

• BNF, 2019. British National Formulary App April 2019 (iOS). BNF Publications. Royal Pharmaceutical Society of Great Britain [accessed 20/04/19]
• BRUCE, Adrian S. & LOUGHNAN, Michael S. 2003. Anterior eye disease and therapeutics A-Z. Oxford; Butterworth-Heinemann.
• Christophers J, Clayton J, Craske J, Ward R, Collins P, Trowbridge M, Darby G, 1998. Survey of Resistance of Herpes Simplex Virus to Acyclovir in Northwest England. Antimicrobial Agents and Chemotherapy. 1998;42(4) 868-872; DOI: 10.1128/AAC.42.4.868
• Chucair-Elliott Ana J, Zheng Min, Carr Daniel J. J., 2015. Degeneration and Regeneration of Corneal Nerves in Response to HSV-1 Infection. Invest. Ophthalmol. Vis. Sci. 2015;56(2):1097-1107. DOI: 10.1167/iovs.14-15596. [viewed 18/04/19]
• FAROOQ A, SHUKLA D, 2012. Herpes Simplex Epithelial and Stromal Keratitis: An Epidemiologic Update. Survey of Ophthalmology. 2012;57(5):448-462 doi: 10.1016/j.survophthal.2012.01.005 [viewed 18/04/19]
• KANSKI, Jack J. 2003. Clinical Ophthalmology: A Systematic Approach, Fifth Edition, Butterworth-Heinemann.
• NHS TAYSIDE, 2019. Ophthalmology Specialist formulary list. 2019. [online] NHS Tayside. [viewed 18/04/19] available from: https://www.nhstaysideadtc.scot.nhs.uk/TAPG%20html/Specialist%20Lists/PDF/Ophthalmology.pdf?UID=6546895822015119122230
• NICE, 2016. Herpes simplex – ocular Scenario: Management [online]. NICE [viewed 17/04/19]. Available from: https://cks.nice.org.uk/herpes-simplex-ocular#!scenario
• THE COLLEGE OF OPTOMETRISTS, 2018a. Clinical Management Guidelines: Keratitis (marginal) [online]. The College of Optometrists [viewed 17/04/19]. Available from: https://www.college-optometrists.org/guidance/clinical-management-guidelines/keratitis-marginal-.html
• THE COLLEGE OF OPTOMETRISTS, 2018b. Clinical Management Guidelines: Microbial keratitis (Acanthamoeba sp.) [online]. The College of Optometrists [viewed 17/04/19]. Available from: https://www.college-optometrists.org/guidance/clinical-management-guidelines/microbial-keratitis-acanthamoeba-sp-.html
• THE COLLEGE OF OPTOMETRISTS, 2018c. Clinical Management Guidelines: Microbial keratitis (bacterial, fungal) [online]. The College of Optometrists [viewed 17/04/19]. Available from: https://www.college-optometrists.org/guidance/clinical-management-guidelines/microbial-keratitis-bacterial-fungal-.html
• THE COLLEGE OF OPTOMETRISTS, 2018d. Clinical Management Guidelines: Herpes Simplex Keratitis (HSK) [online]. The College of Optometrists [viewed 17/04/19]. Available from: https://www.college-optometrists.org/guidance/clinical-management-guidelines/herpes-simplex-keratitis-hsk-.html
• THE COLLEGE OF OPTOMETRISTS, 2018e. Optometrists’ Formulary – Aciclovir 2018. [online] The College of Optometrists. [viewed 18/04/19] Available from: https://www.college-optometrists.org/guidance/optometrists-formulary/aciclovir.html
• THE COLLEGE OF OPTOMETRISTS, 2017a. Clinical Management Guidelines: Keratitis, CL-associated infiltrative [online]. The College of Optometrists [viewed 17/04/19]. Available from: https://www.college-optometrists.org/guidance/clinical-management-guidelines/keratitis-cl-associated-infiltrative.html
• THE COLLEGE OF OPTOMETRISTS, 2017b. Guidance for professional practice – Consent: C27 & C33. [online] The College of Optometrists. [viewed 20/04/19] Available from: https://guidance.college-optometrists.org/guidance-contents/communication-partnership-and-teamwork-domain/consent/#open:190
• Wilhelmus KR, Coster DJ, Donovan HC, Falcon MG, Jones BR, 1981. Prognostic Indicators of Herpetic Keratitis: Analysis of a Five-Year Observation Period After Corneal Ulceration. Arch Ophthalmol. 1981;99(9):1578–1582. doi:10.1001/archopht.1981.03930020452009 [not viewed cited in Farooq, 2012]
• Zemaitiene R, Rakauskiene M, Danileviciene V, Use V, Kriauciuniene L, Zaliuniene D, 2019. Corneal esthesiometry and sub-basal nerves morphological changes in herpes simplex virus keratitis/uveitis patients. Int J Ophthalmol 2019;12(3):407-411 DOI:10.18240/ijo.2019.03.09 [viewed 18/04/19]