Pain
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Duration of acute herpetic pain (AHP) in 1431 patients for whom treatment was begun within 14 days after the onset of herpes zoster (HZ) was analyzed with respect to age, involved region, and severity of skin lesions. All patients were treated with repeated sympathetic nerve blocks until their pain was almost nil. Severity of the skin lesions at the worst phase was defined as mild when they covered less than one-quarter of the primary dermatome, as severe when they covered more than three-quarters of the primary dermatome, and moderate if they were between mild and severe. ⋯ Multiple stepwise regression analysis revealed that the most important factors influencing the duration of AHP were the severity of skin lesions of HZ at the worst phase (r = 0.412), age (r = 0.277) and the involved region (r = -0.101). Thus, AHP in the elderly and in cases of trigeminal involvement is longer because of higher frequencies of severe HZ in the elderly and in trigeminal involvement rather than "being aged' and "trigeminal involvement' itself. We propose that one needs to analyze the results of treatment of AHP with respect to the severity of skin lesions at the worst phase.
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The mechanical allodynia and edema related to a subcutaneous carrageenin injection are increased by a conditioning carrageenin injection 7 days before (Guilbaud et al., 1992). In the present study, the possibility of preventing this by bupivacaine infiltration was tested. In the first part of the experiment, the time course of a carrageenin induced inflammation of the right hind paw was assessed in animals receiving local anesthetic injection (0.2 ml of bupivacaine 0.5% solution with epinephrine) either 5 min before (BUPI PRE group) or 60 min after (BUPI POST group) the carrageenin injection (0.2 ml of 1% solution). ⋯ In contrast, the increase in allodynia and edema was less intense in the BUPI PRE group than in the other groups (P < 0.0001 and P < 0.02 respectively). Bupivacaine injections had no effect on allodynia and edema related to a second contra-lateral carrageenin injection. These results suggest that bupivacaine infiltration, when administered before the first conditioning injection of carrageenin, can prevent the reinforcement of mechanical allodynia and edema related to a second ipsilateral injection of carrageenin 7 days later.