Application Of Quantitative Sensory Testing In Herpes Zoster And Postherpetic Neuralgia

Objective: The change of QST(quantitative sensory testing) in somaticnerve small fibers of patients with herpes zoster and with PHN(post herpetic neuralgia) was observed to discuss the pathogenesis of PHN and explore the method forecasting PHN in acute herpes zoster, to prevent or decrease the appearance of PHN.Methods: One hundred and three patients with herpes zoster werecollected. There were 62 males and 41 females, age from 18-83 years old and the mean age was 58.14+15.57 years old. All patients were tested by QST and VAS(visual analogue scales) in acute zoster and one month after healing of rash to evaluate the magnitude of thermal sensory deficits and pain intensity. Compare the results from patients with PHN and without PHN and research whether forecasting PHN is one of the functions of QST.Results:1. Fifteen of 103 patients of HZ had suffered from PHN. The incidence of PHN is 14.56%.2. There were significantly lower thresholds of CS and CP and higher thresholds of WS for rash or pain skin than for mirror-image area in patients of acute zoster, but there were no differences in the thresholds of HP between rash or pain skin and mirror-image area. There were significantly bigger dispersions of CS,WS,CP for rash or pain skin than for mirror-image area.3. There were no differences in the thresholds of all kinds of temperature sensory in patients without PHN one month after healing of rash between rash skin and mirror-image area. There were no differences in the dispersions of all kinds of temperature sensory in patients without PHN one month after healing of rash between rash skin and mirror-image area.4. There were significantly lower thresholds of CS and CP and higher thresholds of WS,HP for pain skin than for mirror-image area in patients with PHN one month after healing of rash. There were significantly bigger dispersions of all kinds of temperature sensory for rash or pain skin than for mirror-image area.5. There were significantly lower thresholds of CS and CP and higher thresholds of WS,HP for pain skin in patients with PHN than in patients without PHN in acute zoster. There were significantly lower thresholds of CS for rash skin than for mirror-image area in patients without PHN, but there were no differences in the thresholds of WS,CP,HP between rash or pain skin and mirror-image area. There were significantly lower thresholds of CS and CP and higher thresholds of WS,HP for pain skin than for mirror-image area in patients with PHN. There were no differences in the dispersions of all kinds of temperature sensory for mirror-image area between patients without PHN and patients with PHN.6. There were significantly smaller dispersions of CS,WS,CP and no differences in the dispersions of HP for patients with PHN in acute zoster than one month after healing of rash.7. There were no differences in the thresholds of all kinds of temperature sensory for mirror-image area in all patients between acute zoster and one month after healing of rash. There were no differences in the dispersions of all kinds of temperature sensory for mirror-image area in all patients between acute zoster and one month after healing of rash.8. In all patients, there was significant relativity between the dispersions of CS and other kinds of temperature sensory. There was good coherence between the results of all kinds of temperature sensory.9. In acute zoster VAS scores in patients without PHN were significantly lower than in patients with PHN. VAS scores of patients with PHN one month after healing of rash were significantly higher than those in acute zoster.Conclusion:1. QST is a good testing to reflect the function of small nerve fibers inpatients with herpes zoster and PHN.2. QST can be applied in patients with herpes zoster to forecast whether PHN appears early in acute herpes zoster.3. The mechanism of pain in acute zoster is possibly correlated with local inflammation response; the mechanism of pain in PHN is possibly that the increased activation of sensory afferent small nerve and exceptional discharge brings excess excitement of central, and other mechanisms exist.4. Rational use of drugs in patients with herpes zoster in advance according to QST results in acute zoster is possible to prevent or decrease the appearance of PHN and avoid drug abuse. Further research is necessary in clinic.