Postherpetic neuralgia

Introduction Post-herpetic neuralgia is a neuropathic pain syndrome that occurs after infection with acute herpes zoster. Most patients with herpes zoster can be recovered after treatment, but some patients have pain in the damaged skin area after herpes has healed for more than 3 months, called post-herpetic neuralgia. The neuralgia after the rash lasts longer, especially in elderly patients. There may be more than half a year.

Cause

After infection with herpes zoster virus, 10% of patients have pain for more than one month. If they are not treated or treated improperly, the pain can still exist after the disappearance of herpes. In some cases, the pain is even more than a few decades. It is related to the age of onset. Patients less than 40 years old rarely occur. The incidence rate of patients over 60 years old is 50%, and the incidence rate of patients over 70 years old is 75%. About 10%~25% of patients with residual neuralgia can continue to suffer more than pain. One year. May appear before the rash or with a rash.

an examination

Related inspection

Laboratory tests for fungal infections

This part of the patient accounts for 9 to 34% of the total acute herpes zoster. The skin area of the damaged area has acupuncture or burning sensation, and the pain is severe. The patient is deeply troubled. The normal diet and sleep are affected, which is very painful.

Laboratory inspection:

For some cases that are difficult to diagnose clinically, cytological or histological diagnosis may be used. For tissue culture, essentially as with herpes simplex, serum antibodies and vesicles contain complement-binding antigens by immunofluorescence. Giant cells with deep-stained nuclei were seen early in cell smear, and were also found in tissue specimens of ulcer or blister base.

Immunofluorescence using specific anti-VZV serum can detect VZV antigen in diseased cells, which is helpful for rapid diagnosis. Others may also use enzyme-labeled techniques or specific monoclonal antibodies for better diagnostic results.

Histopathology showed: 1 ganglion has inflammatory cell infiltration, hemorrhage and degeneration, blister formation near the epidermis and dermis, swelling and degeneration of blister cells. 2 There are lymphocytes, fibroblasts, polynuclear leukocytes, plasma cells and monocytes infiltrating under the blisters. 3 Lipsch-ütz inclusion bodies of herpes zoster can be seen in the nucleus of the affected cells. 4 herpes zoster vasculitis and bleeding.

Differential diagnosis

Skin Lightning Pain: If there is "lightning pain" on the surface of the skin and a similar situation occurs for several days, it may be asymptomatic herpes zoster. The skin of the diseased part has the size of mung bean, the papules with large tension, and the blisters. The light can have a normal skin interval in each cluster. In severe cases, the large pieces can be fused and distributed in a strip shape. After a few days, the clear and transparent blisters become turbid pus. The blister can be partially broken to form a smash, and this type of syndrome is easier to distinguish. However, in a few cases, there is only neuralgia and no skin damage. This asymptomatic herpes zoster is easily misdiagnosed. If the lesion occurs on the face, it is easy to be misdiagnosed as trigeminal neuralgia; it occurs at the edge of the rib and is easily mistaken for intercostal neuralgia. Other misdiagnosis is angina pectoris, ulcer disease, biliary or renal colic, appendicitis, or early glaucoma. Often some middle-aged and elderly patients still have pain after the herpes zoster has completely retreated, and the local skin is intact but not dare to touch. This is because the nature of herpes zoster pain is inflammation or even necrosis of the affected ganglia. The degree of pain and the length of time are not necessarily consistent with the rash. Especially if the physical condition is poor, or if the treatment is not timely, the pain can last for several months or even longer.

Skin pain: Skin pain is divided into two types: fast pain and slow pain. Quick pain is a sharp and sharp tingling. Slow pain is a burning pain that is unclear and unbearable. The rapid pain is very rapid when the skin is stimulated. It is a sharp and sharp sting that is quickly removed after the stimulation is removed. Slow pain is a burning pain that is unclear and unbearable. It occurs after 0.5 to 1 second after stimulation, and lasts for a long time, accompanied by changes in heart rate, blood pressure, breathing, and mood.

This part of the patient accounts for 9 to 34% of the total acute herpes zoster. The skin area of the damaged area has acupuncture or burning sensation, and the pain is severe. The patient is deeply troubled. The normal diet and sleep are affected, which is very painful.

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