Recovering from chickenpox, Herpes zoster virus remains in the body in a latent stage and is localized mainly in the sensory ganglia of the spinal nerves and the trigeminal nerve.
During reactivation the virus causes a characteristic vesicular rash and appears pain in the area of innervation of the corresponding nerve root. In 50% of patients with localized rash on the trunk, 20% - on the head, 15% - on the hands, 15% - on the feet. A few days later transformed into pustular eruption, and then forms a crust and by the end 3rd to 4th week disappears.
However, in many patients even after the disappearance of the rash a lot of pain remains in the affected dermatome for months or even years. This pathological condition is called post-herpetic neuralgia (PHN). Very often herpetic neuralgia develops in patients over the age of 60 years (50%). Pain associated with inflammatory changes in the dorsal root ganglia of the brain spinal cord and peripheral nerves (leading to pathophysiological mechanisms - ectopic activity, the expression of sodium channels in the membranes of nerve cells, as well as central sensitization).
In patients with post-herpetic neuralgia there are 3 types of pain: permanent, deep, dull, compressive or burning; spontaneous, recurrent, stabbing or shooting ("shock") and allodynic (acute, superficial, burning, usually occurs when a light touch). In most patients, pain associated with post-herpetic neuralgia, decreases during the 1st year. However, in some patients it can persist for years or even for the rest of the life.
Post herpetic neuralgia has a significant negative impact on quality of life and functional status of patients who may develop affective disorders such as anxiety, depression, as well as disturbance in social activity, sleep, and appetite.
Intraosseous blockade can reduce the pain, the clinical manifestations of post-herpetic neuralgia and improve the patients quality of life.