What is shingles? What is considered postherpetic neuralgia
Herpes zoster, a skin disease caused by varicella-zoster virus infection, is a painful and predominantly herpetic lesion of the skin in the innervated area after the virus invades the nerves. In most infected individuals, the herpes heals and the pain disappears within a few weeks. However, some people, especially older people, have pain that persists even after the herpes has healed. Pain that persists for more than three months after the herpes has disappeared is called postherpetic neuralgia. Those who have had the pain for more than one year are referred to as having intractable postherpetic neuralgia.
The varicella-zoster virus mostly invades the intercostal nerves (53%), so the lesions are mostly located in the thoracolumbar region, in the shape of a band, and are also known in folklore as “waist-wrapping fire dragons” or “serpentine sores”. The disease can invade any part of the body, including the cervical nerve (20%), the first branch of the trigeminal nerve in the head (15%), as well as the abdomen, extremities, ears and other mucosal herpes zoster, which can invade the eyes, mouth and perineum.
Postherpetic neuralgia can become electric shock-like or fire-like pain, or it can become itchy or vague pain. Some patients are even afraid to wear clothes or wash their faces because of the pain.
How to treat post-herpetic neuralgia when it is so torturous
Treatment principles : 1.
1, shingles acute pain should be timely pain relief, for the prevention of post-herpetic neuralgia has important significance.
2, the acute phase of the herpes is heavy, Chinese medicine internal + external use fast effect. In the acute stage, the main purpose is to clear heat and detoxify dampness and relieve pain, while in the later stage, the main purpose is to nourish Yin and activate blood circulation and relieve pain.
3, hormones in the early herpes exuding heavily used as little as possible or not, if the pain is intense appropriate application.
4, postherpetic neuralgia is a kind of stubborn pain, single method of treatment is not good, should use comprehensive treatment, often a combination of methods together to control or significantly relieve pain, so that it does not affect normal life and work.
The treatment of postherpetic neuralgia is still a worldwide problem. However, the pain symptoms of the majority of patients can still be controlled or significantly relieved.
1. Drug treatment
Internationally recommended first-line drugs for postherpetic neuralgia treatment: gabapentin, pregabalin, etc. Gabapentin and pregabalin are similar to carbamazepine as anti-epileptic drugs, but the side effects are significantly less than those of carbamazepine and other drugs. Regular check-ups of liver and kidney function and blood tests are needed for more than three months to avoid bone marrow suppression. Analgesic drugs such as tramadol are also commonly used in the treatment of postherpetic neuralgia and are often combined with gabapentin and pregabalin.
Other commonly used drugs include antidepressants, hormones, nonsteroidal analgesics and anti-inflammatory drugs, and local anesthetic patches. Medication can significantly reduce the pain symptoms of patients, and some patients only need medication. However, for patients with intractable postherpetic neuralgia, medication can only reduce the symptoms but not control the painful outbreak of postherpetic neuralgia. For patients with intractable postherpetic neuralgia, other treatment modalities are needed in addition to medication.
2.Nerve block
Nerve blocks are effective in controlling the outbreak pain of postherpetic neuralgia, especially in the early stage of postherpetic neuralgia. Commonly used nerve block methods include epidural block, nerve root block, sympathetic nerve block and so on. Nerve blocks require a certain amount of time, usually about two weeks.
3. Intradermal injection
It is mainly applied to the trigeminal nerve distribution area, C3-L2 distribution area posterior neuralgia.
Intradermal injection is to block sympathetic nerve endings to treat herpes zoster and herpes zoster neuralgia, which blocks the efferent impulses of sympathetic nerves, causes vasodilation, relieves local vasospasm, blocks the vicious cycle of pain, achieves rapid analgesia, and keeps a longer period of pain-free. Intradermal injection of analgesic solution, containing 5ml of 0.5% bupivacaine, 500ug of Micropol and 10ml of 0.9% saline, totaling 16ml, is injected by dotted encirclement method or sheet encirclement method.
Inject 0.2-0.4ml of analgesic solution into each spot, inject once a day for 3 days, 3 times as a course of treatment, usually 4-6 times, at least 3 times, at most 10 times.
Intradermal injection of drugs such as botulinum toxin also has some effect, especially for postherpetic neuralgia with skin friction pain.
4. Spinal cord electrical stimulation
Spinal cord electrical stimulation treatment is performed by percutaneous puncture under local anesthesia, after entering the epidural cavity, electrodes are placed in the segment involved in the lesion and electrical stimulation is given. The electrode position is adjusted according to the extent of the torso producing numbness, and when the painful area is completely covered, the electrode is then connected to a portable stimulation generator outside the body through a wire. The patient is discharged 24 hours after the procedure, and then the therapeutic effect of electrical stimulation on pain is observed for 2-3 weeks.
It is indicated for patients with pain that has not been treated by other means. Brain electrical stimulation methods have been reported in the literature for analgesic stimulation of the conduction duct and periventricular gray matter, head of caudate nucleus, amygdala, and limbic system.
5. Nerve destruction
After the above treatment, some patients still cannot control their pain, then neurodestruction treatment can be considered. Postherpetic neuralgia usually occurs in the chest, ribs, back and face, and nerve destruction can be considered for sensory nerve destruction in these areas because it does not seriously affect other functions of the patient if well controlled. Nerve disruption can be performed by chemical disruption or radiofrequency disruption.
Chemical destruction is now less commonly used because it is less controllable, while radiofrequency destruction is safer because it is more controllable and therefore more commonly used. It should be noted that due to the important sites involved and the unseen nerves, nerve disruption of the thoracic dorsum is not as easy as we think, with a success rate of 50-60%, while facial nerve disruption has a higher success rate of over 90%. For other areas of postherpetic neuralgia, such as postherpetic neuralgia that occurs in the extremities, nerve disruption is not suitable for treatment.
In conclusion, postherpetic neuralgia is a very difficult to treat neuropathic pain, and the above-mentioned comprehensive treatment can control the pain of most patients to an acceptable level, so that it does not affect the normal life of the patient.