Post - Herpetic Neuralgia "Pain after Shingles"
Post - Herpetic Neuralgia is a condition which produces severe, agonizing pain and suffering for many patients following the viral infection, herpes zoster, more commonly known as shingles. This painful condition resulting from shingles may last several months to years. In addition to patient suffering, the management and control of pain and anguish is one of the most difficult and frustrating problems encountered by the patient's physician.
Shingles (herpes zoster) are an acute viral infection affecting the skin and nerves, and is characterized by groups of small blisters appearing along certain nerve segments. The lesions are most often seen on the back and may preceded by a dull ache or severe pain in the affected site.
Shingles is caused by the same viral infection as that of chicken pox. It is more commonly seen in individuals with reduced defense mechanisms to fight infection by a reactivation of the chicken pox virus which was inactive. It most commonly affects chest wall and upper back (50% of cases), upper back and upper limbs (20% of cases), lower back and lower limbs (15% of cases), and the eye (15% of cases).
Healing Process & Complications
In most cases (85%), complete healing occurs in two to six weeks. Overall, 15% of the patients progress to a condition known as post-herpetic neuralgia (inflammation of nerves after shingles). In most young patients this may last for only a week or two after healing.
Other complications include generalized herpes zoster, wherein lesions may spread all over the body, even to the heart and lungs. This is more frequently seen in patients with Hodgkin's disease (a type of cancer), and patients receiving medications which affect the immune system.
*It is reported that, as many as 70% of the patients over age 60 may develop post-heretic neuralgia and continue to have varying degrees of pain for months or even years after skin lesions have healed
Causes of Pain
1. This disease mainly involves nerve root ganglion (collection of nerve tissue) which may be replaced by scar tissue. This scar tissue may be the cause of various problems, one being reducing the diameter of blood vessels.
2. Unequal damage of the large diameter nerve fibers than small fibers, which changes the balance and allows the brain to transmit pain impulses without obstruction. In general, older patients have fewer large fibers and their capacity for regeneration of these fibers is low.
There are basically two approaches to treatment used by physicians: One approach tries to prevent shingles from developing into post-herpetic neuralgia, and the other treats the neuralgia after it starts.
Some physicians believe that shingles will cure itself and that we should treat the problem only when it develops into post-herpetic neuralgia. However, treatment of post-herpetic neuralgia is frustrating both for patients as well as physicians, as there is no reliable treatment after the painful condition starts. Hence, we agree with the physicians who believe that treatment should be started in the early stages of the disease to obtain the best results.
Goals of Treatment
The major goal of Pain Management is to put you back in charge of your life. The overall relief from chronic pain depends on more than just treating the damaged area of the body. It is possible that you will always have to live with a certain amount of pain, but you can learn to work and enjoy life in spite of it. Our aim is to make progress with small victories which add up and produce a big improvement in the qualify of your life
We offer numerous approaches:
Injections are administered in various forms, such as subcutaneous or intracutaneous infiltration, trigger point injections (injections into the area responsible for pain), nerve blocks (injections around the nerves transmitting pain), sympathetic blocks (injections around sympathetic ganglions), epidural blocks and epidural steroids (injections into the space outside the membrane covering the spinal cord).
Injections are very successful in this condition if started in the early stages. In a typical case of therapy, a series of injections are required. Each injection provides relief that exceeds the duration of action of local anesthetic, and additional blocks also provide relief that exceeds relief by the previous block. Often, a staircase-type phenomenon is reached in which there is some degree of permanent relief with each injection.
Injections are repeated as pain starts returning, however with reducing frequency as time passes. Some patients require only one or two injections, while some of them may need several.
In summary, there is a close relationship between the duration of the neuralgia and the effectiveness of treatment. Prompt treatment in the first three weeks shortens the progressive course of the disease and also decreases its severity. There is also a correlation between the age of the patient and the response to therapy. The incidence of post-herpetic neuralgia is higher in older persons and their response to therapy is poor. Hence, the best way to prevent neuralgia following shingles is to diagnose and treat the disease early in the acute stage.