Let's Talk About Herpes! Part 1
Part 1 of 4: Demystifying Ocular Complications of Herpetic Disease
Herpes… the gift that keeps on giving. Seemingly simple to detect and treat based on textbooks, until it isn’t. I find many physicians, both outside and within our subspecialty, seem to have difficulty diagnosing and managing these pesky critters. Plural, because there are multiple villains in this story. Luckily, as my students will note, herpes is one of my favorite topics, and I am happy to help simplify this enemy of the eye in this three-part newsletter.
Let’s start with the basics….
There are 8 currently known human-herpes viruses (HHV) that take a ride on the human DNA train. DNA being the operative designation, as herpetic viruses are DNA viruses by nature. ***Remembering back to basic microbiology… There are RNA and DNA viruses.. oh and retroviruses*** Will discuss later… But, what is important with DNA viruses is they actually incorporate themselves into the nuclear DNA of affected cells. Thus, when those cells replicate, the viral DNA also replicates, hence the phrase, “Herpes is forever.”
The 8 human-herpes viruses are: herpes simplex-1 (HSV1), herpes simplex-2 (HSV2), varicella-zoster (VZV), Epstein-Barr (EB), cytomegalovirus (CMV), (then the creatively named) human-herpes virus 6, human-herpes virus 7, and Kaposi’s carcinoma (KC).
Of these 8 herpes viruses, our field typically only has to juggle 3 of them: HSV1, HSV2 and VZV. HHV 6 and 7 are typically neonatal, and obscure in presentation. They are also often undiagnosed officially, and don’t often cause long-term issues. We definitely have heard of CMV and KC; however, the ocular complications of these are both typically only noted in severely immunocompromised patients such as in AIDS and intensive chemotherapy patients, etc.
Thus, in the daily clinic run, in the US at least, we will most often run into HSV1, HSV2 and VZV cases, and we need to be vigilant in managing these in an effective and viable way for the patient. Some of you may say, “Well, HSV1 is above the belt, and HSV2 is below the belt.” And, you would typically be correct; however, HSV2 can also occur above the belt, and HSV1 can occur below the belt… sorry to say.
HSV1 is typically given from parent to child, not on purpose, through general affection. Parents with a history of ‘cold sores’ often pass along to child. HSV1 and/or HSV2 can be passed along during birth as well. HZV is typically passed along via childhood infection of chicken pox. However, younger generations will not have the same instances of VZV moving forward due to relatively successful childhood vaccination of VZV (more on that later).
In any event… These cases are very, very common! Based on a simple Google search, 50%-80% of people alive carry HSV1 (probably closer to 80%), 12%-15% of the population carry HSV2 and an unavailable number carry HZV. As we all remember, “chicken pox parties,” historically nearly everyone had chicken pox at some point in time. However, with the relatively recent addition of VZV vaccination added into childhood vaccinations alongside MMR, etc. we may get to a point where shingles is basically eradicated as a disease process since the vaccine is an inactivated virus. Will be interesting to see how this pans out in the future…
The good news! Is that the majority of these cases are easily managed with effective and aggressive management. Many studies have been done on treatment of the ocular manifestations of these diseases, most notably the HEDS (Herpetic Eye Disease Study).
This study has multiple important points:
Establishing standard of care protocols for oral and/or topical management
Determining efficacy of oral vs topical antiviral (AV) treatment for both HSV and HZV keratitis
Determining efficacy of steroid treatment alongside antiviral (AV) treatment for stromal HSV keratitis and all VZV keratitis
Determining efficacy of prophylactic treatment dosages for antiviral (AV) treatment for HSV and ZVZ keratitis
In general, herpetic eye disease effects one side of the head/face at a time, along terminal endings of facial nerves. Often, this is a distinguishable character trait of this virus, leading to prompt diagnosis and treatment. However, herpes often is known as a ‘masquerader’ and likes to hide in the shadows with underwhelming signs/symptoms until provoked.
All of these points will be expanded as we continue our herpes journey in the following parts. During this segment we will explore how to manage various cases of HSV and VZV, including unique cases that don’t follow the book, and the ramifications of vaccination including the VZV vaccines, and the “shingles” vaccines.
The next segment will dive into basic cases of HSV ocular manifestations, what to look for, and how to address. Zoster will follow, then some more complicated cases as an example of when herpes doesn’t follow the rules.
Thank you for following the RealEyes substack. Let’s become better together!
- Shane Sanders, OD