Monday, March 30, 2015

Postherpetic Neuralgia

Postherpetic Neuralgia Postherpetic neuralgia is a type of viral infection affecting the nerve cells. It occurs as after effect of shingles infection. PHN causes burning intense pain on the affected area of the body, due to damage of nerve cells. Pain may last for many months or even a year for some people. People who have got shingles infection are at high risk of developing postherpetic neuralgia. Treatment for PHN is available in the form of painkiller drugs. You can prevent PHN and shingles by vaccination.


Causes :


The underlying nerve cells are damaged when the HZ virus passes down from the skin till the nerve of the affected area. Shingles are so severe infection that it causes blisters or lesions on the skin. Normally the viruses will be destroyed by antiviral medications and further treatment. However the virus may still remain dormant inside the body in the dorsal root cells. Not all the people affected with shingles infection would develop PHN. Only few (9-14%) of the people may develop PHN after few months.


Who are at risk?


People who have got shingles infection are at high risk of getting PHN after 2-3 months. Aged people and people with weakened immunity have increased risk of developing PHN after shingles. Family history also plays role in PHN disorder since close relatives of affected people (with PHN) are at risk of getting PHN later.


Symptoms :


Intense burning pain on the affected body part is the only symptom of PHN. The person who gets shingles infection will develop painful blisters on the skin in some part of his body. After the infection is treated completely, the blisters may disappear leaving a scar.


But the nerve cells below are totally damaged by severe infection, which may cause jabbing pain. The pain may become so severe that the person affected cannot even tolerate slight rubbing of clothing over the affected area. In extreme cases, the affected part of the body may become paralyzed due to damaged nerves.


Diagnosis :


Your doctor can detect PHN by the severity of the symptoms of intense pain. He would collect the medical history of the patient to know if he has got shingles infection. If required, he may do a biopsy of the affected tissue sample.


Treatment :


Treatment options vary depending on the intensity of the pain and health condition of the patient. Combination of two or more medications is often prescribed for managing throbbing pain. Anticonvulsant drugs like carbamazepine or gabapentin are given to reduce the intensity of pain due to PHN.


Some doctors prescribe tricyclic antidepressant drugs like desipramine or amitriptyline for managing pain caused by postherpetic neuralgia. In addition painkillers like morphine or oxycodone that belong to narcotic category are also given. Topical creams like capsin or zostrix that are given for shingles infection can be applied on the affected area of the body. Lidoderm is highly effective ointment to reduce pain.



  • Nerve Stimulation :


This therapy is based on the concept that effective electric current can block the nerve sensors in the body. Pain causing nerves are paralyzed by passing small amounts of controlled electric current on the affected area of the body. This process is called as TENS stimulation. Local nerves of the affected area can be blocked by effective injection or surgery (by cutting the nerve) so that the person may not sense any more pain.


Complications :


The affected person will soon become addicted to painkiller drugs to manage pain. For many people, quality of life may be affected due to intense throbbing pain. The person may not get enough sleep due to persistent pain.


Outlook :


Many patients would recover from PHN after taking painkillers for few months. But for some people the pain may last for a year or even more affecting the quality of life greatly. In rare cases it can cause total nerve damage.


Prevention :


You can prevent developing PHN as well as shingles by getting a shot of Zostavax vaccine. People who are above 50 years can now take this vaccine to prevent shingles and PHN.


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