GENITAL HERPES
Introduction
Genital herpes is caused by infection with a member of the herpes virus
family, herpes simplex. Two types of herpes simplex virus have been identified,
HSV-1 and HSV-2. HSV-2 is the major cause of genital herpes; HSV-1, the cause
of cold sores, is also implicated in about 10% of cases.
Herpes viruses infect the body through mucous membranes such as the lips,
and broken skin. In genital herpes, initial infection generally occurs through
sexual contact with an infectious partner. However oral sex is increasingly
acknowledged as a contributing factor in the transmission of genital herpes
caused by HSV-1.
Upon infection, virus particles are transported to the nerve cell bodies,
mostly located within the spinal column, where they lie dormant until they are
reactivated. While dormant, the virus does not replicate or cause cell death.
Reactivation of the latent virus occurs from time to time, often set off by
a specific trigger factor such as stress, menstruation, fatigue and sexual
intercourse. The mechanisms behind reactivation are not fully understood;
reactivation can occur in both immunocompetent as well as immunocompromised
individuals. Once reactivated, virus particles travel back up the nerve pathway
to the skin, initiating a recurrent attack of genital herpes.
The size of the problem
Reported Cases genital herpes is a common condition. Department of Health
statistics for England and Wales show that 24, 351 patients presented to a
medical practitioner with genital herpes in the year ending 31 December 1992,
(1) and 58% were first episode patients. However, UK market
research conducted in July 1994 indicated that up to 136,500 genital herpes
patients attended hospital outpatients,(2) and GP research
shows on average that up to 84,000 patients are seen, at least initially, in
general practice.(3)
Department of Health statistics also show that genital herpes is the second
fastest growing sexually transmitted disease in England and Wales.(4) This may be due to many factors including increased public
awareness, an increase on the average number of sexual partners per person and
earlier first sexual contact.
Seroepidemiology
The most accurate way of defining the number of individuals who carry HSV-1
or HSV-2 is to conduct seroepidemiological studies. This approach is more
common in the US, where reports variously indicate a serorevalence within the
population of 20%-60%.(5) In the UK, a study performed in
London showed 23% of attendees at a genitourinary medicine clinic were
seropositive for HSV-2. This compared with 8% of blood donors, generally
considered to be a low risk group.(6)
Fortunately, not all those who carry the virus will experience an attack of
genital herpes. Many individuals are symptomatic, while others will experience
a subclinical infection. Overt cases of genital herpes range from mild to
severe; the severity of the outbreak depends on many factors including patient
gender, and immune status.(7)
Impact of diagnosis
The impact on a patient of the diagnosis of genital herpes varies enormously
depending on age, sex and social circumstances. European attitudinal market
research conducted in July 1994 shows that patients express a variety of
feelings on diagnosis. These include shock, disgust, anger, fear, embarrassment
and shame.(8)
Questions most commonly asked by patients include how and where they caught
the disease, and how to tell their partner.
Natural history
The natural history of the disease passes through three distinct phases:
- Primary/first episode genital herpes
- Latency
- Recurrent genital herpes
The complications of genital herpes occur most frequently with primary
attacks but occasionally occur with a recurrence.
First episode
In most cases first episode genital herpes is a severe disease which occurs
over several weeks.
However, in some cases the acquisition of genital herpes may go unrecognised
or be asymptomatic.
First episode genital herpes can be classified as a true primary attack in
which there is no aerological evidence of previous infection; or a non-primary
first episode, where medical attention has been sought by a patient for the
first time although there is aerological evidence of previous herpes infection.
First episode genital herpes tends to be more severe in women than in men;
women are also twice as likely as men to have systemic symptoms, aseptic
meningitis and dysuria.'
Lesions are often multiple, beginning as vesicles (blisters) and progressing
through the stages of ulcer formation, crusting and healing. The initial crop
of lesions is often extensive and accompanied by severe pain and systemic
symptoms such as fever and malaise.
Complications of first episode genital herpes may include HSV pharyngitis,
viral meningitis and urinary retention, occasionally requiring hospital
admission.
Recurrent genital herpes
It is commonly thought that up to 60% of patients will experience at least
one attack of recurrent genital herpes following the primary episode. The
frequency and severity of recurrent attacks is variable and depends on many
factors, including the type of virus (HSV-1 or HSV-2) causing the infection.
Although the patient may attribute the recurrence to a particular trigger
factor, the immunological cause of recurrences is not known. For most patients
the number and severity of attacks decreases over time.
Approximately 50% of recurrent episodes are preceded by a prodrome. The
prodrome may precede lesions by anytime from less than an hour, to two days.
Prodromal symptoms include a tingling sensation, pain in the buttocks, or
itching and pain in the groin.
Diagnosis
Clinically, genital herpes should be suspected in any patient who presents
with genital ulcers. Genital herpes is a more likely diagnosis when there are
multiple rather than single ulcers, when ulcers are painful, when they are
recurrent or preceded by a prodrome and when lymph nodes are enlarged.
Therapy is usually initiated on the basis of a clinical diagnosis. In a
hospital clinic the diagnosis of genital herpes is confirmed by viral culture
grown from a swab of the lesions. However it may be more difficult to arrange
these tests from a GP surgery, as appropriate viral transport media and
laboratory facilities are required
Management of genital herpes
The management of a patient with genital herpes ideally starts at the
initial diagnosis, by explaining the diagnosis empathetically and offering
advice and counselling.
In the setting of a genitourinary medicine clinic, after the initial
diagnosis and advice have been given by the doctor, the patient may be referred
to a Health Advisor for further advice and information.
Areas on which advice may be offered include:
- risk of transmission of genital herpes
- asymptomatic viral shedding
- guidelines for sexual contact
- self-help groups
- treatment options available
- genital herpes and pregnancy
Treatment
Therapeutic options for first episode treatment include oral antiviral
therapy, ideally given as early as possible in the course of the disease. In
cases where patients are able to recognise the prodromal symptoms, doctors may
allow patients to initiate their own therapy for recurrences with the overall
aim of aborting the attack.
To date, aciclovir has been the only well tolerated and effective therapy
available for the management of genital herpes. However, aciclovir has to be
given at a five times daily dose in first episode genital herpes and compliance
may be difficult to ensure. Furthermore, patients are likely to find the
regimen somewhat inconvenient.
In January 1994, FAMVIR (famciclovir) was launched in the UK for the
treatment of shingles. In April 1995 the licence for FAMVIR was extended to
include the treatment of first episode and recurrent genital herpes.
FAMVIR is indicated in first episode genital herpes at a dose of 250 mg
three times a day for five days and therefore offers patients a more convenient
dosing regimen and improved compliance compared with aciclovir.
For the treatment of recurrent genital herpes, FAMVIR is given at 125 mg
twice a day for five days.
Genital herpes
References
1. On the State of the Public Health,
1993
2. Taylor Nelson Healthcare: Genital Herpes. STD Clinics -
usage and attitudes study, BJM Hospital Research June 1994
3. Taylor Nelson Healthcare: Omnimed, October 1994
4. Department of Health, Health and Personal Social Services
Statistics for England, 1994 5.johnson RE et al, NEJM 1989; 321: 7
6. Cowan F et al, BMJ 1994; 309: 1325-9
7. Corey L et al, Ann Int Med 1983; 98: 958
8. Taylor Nelson Healthcare. Understanding genital herpes -
the patients' perspective, July 1994
9. Mertz G, Med Clinics N America 1990; 74(6):
1433-1454
|
