Abdominal Pain
4. TREATMENT OF NEUROPATHIC PAIN
4.3. Treatment of Individual Pain Syndromes
Postherpetic neuralgia and CRPS typically require supplemental treatment modalities. Early treatment of each condition with general neuropathic medica-tion and condimedica-tion-targeted therapy may help reduce the risk for more prolonged and recalcitrant pain.
4.3.1. Postherpetic Neuralgia
Early and aggressive treatment of herpes zoster reduces the risk for postherpetic neuralgia. Early antiviral therapy of herpes zoster (within 72 h of symptom onset) can effectively minimize symptoms of postherpetic neuralgia (Table 4). In a large, prospective, double-blind study comparing the rate of postherpetic neuralgia in patients treated with acyclovir or brivudin (a new antiviral agent that is not yet available in the United States), investigators found that the incidence of postherpetic neuralgia was significantly lower with brivudin, although mean duration of postherpetic neuralgia pain was similar in both groups (Fig. 7). Neuropathic therapy administered during the early stages of zoster may also reduce the incidence of postherpetic neuralgia. Low-dose amitriptyline (25 mg/day) administered within 48 hours of the onset of zoster rash significantly reduced the rate of postherpetic neuralgia in elderly patients (mean age: 68 years) (Fig. 8) (31).
Inflammation and increased prostaglandin activity occur in early postherpetic neuralgia (32). In one study, treatment with topical aspirin (750–
1500 mg plus 20–30 mL diethyl ether), but not other nonsteroidal inflam-Fig. 7. Comparison of rate of development of postherpetic neuralgia after anti-viral treatment. Brivudin was superior to acyclovir (p = 0.006). PHN, postherpetic neuralgia. (Based on ref. 30.)
Table 4
Antiviral Therapy for Early Herpes Zoster
Drug Dosage
Acyclovir 800 mg five times a day for 7–10 days Famciclovir 500 mg three times a day for 7 days Valacyclovir 1 g three times a day for 7 days Brivudina 125 mg once a day for 7 days
a Not available in the United States.
Fig. 8. Reduction in persistent pain in patients aged >60 years with acute zoster treated within 48 hours of rash onset with amitriptyline 25 mg/day vs placebo. Differ-ence between amitriptyline and placebo is significant (p < 0.05). (Based on ref. 31.)
matory drugs, reduced pain more than placebo (–66% with aspirin vs –34%
with placebo) (33). The onset of pain relief was rapid (approximately 4 min-utes), with relief lasting a mean of 3.6 hours.
Patients with established postherpetic neuralgia are treated with the neuro-pathic medications listed previously. Both first- and second-line therapies are effective for postherpetic neuralgia.
4.3.2. Complex Regional Pain Syndrome
Complex regional pain syndrome is treated with a combination of medications to achieve symptomatic relief and physical rehabilitation to prevent progression to motor changes, such as reduced range of motion, joint contracture, and motor loss. CRPS occurring during the first few weeks of therapy is often managed with oral corticosteroids (30 mg/day for 2 weeks, followed by a tapering schedule) and sympathetic blocks, including sympathetic ganglion blocks (i.e., stellate, thoracic, or lumbar ganglion blockade) or intravenous regional sympathetic blocks (i.e., Bier blocks) (34). These therapies are combined with vigorous physical therapy. The goal of early intervention with steroids, blocks, or both is to provide temporary symptomatic reduction to allow optimal participation in rehabilitative therapy. Both early and late treatment of CRPS focus on physi-cal and occupational therapy designed to maintain or improve range of motion and maximize active use of the painful extremity. The goal of such therapy is to help the patient resume normal use of the extremity for both functional and casual use, including a return to a normal arm posture when sitting and arm swing during walking. Gait training is essential for patients with lower extrem-ity CRPS to help them regain a normal, unrestricted walking pattern. Although
physical and occupational therapy are often contrary to the desires of the pa-tient with CRPS, who often wishes to minimize movement and stimulation of the painful extremity, the clinician must insist on aggressive therapy and re-sumption of more normal extremity postures and use at all times. Psychologi-cal interventions may serve as invaluable adjunctive pain management for patients with CRPS. Antidepressants, AEDs, and long-acting opioids may also help the patient participate in rehabilitative therapy activities.
5. SUMMARY
Neuropathic pain is seen in general practice, typically in conjunction with systemic medical illness; nutritional deficiency, toxicity, or both; cancer; and infection. Pain reports that include a description of pain and aggravating fac-tors, as well as a clinical examination will help the clinician distinguish neuro-pathic pain from other common pain conditions, including plantar fasciitis, Morton’s neuroma, and entrapment syndromes. Hallmarks of neuropathic pain include a burning sensation, hyperalgesia, and allodynia. Laboratory testing may be needed to identify systemic medical illness but is rarely helpful for diagnosing neuropathic pain.
A variety of effective, symptomatic therapies are available for neuropathic pain. These therapies will not reduce numbness, but can decrease dysethesia, hyperalgesia, and allodynia. Treatment of underlying medical conditions—
such as glucose control in diabetes and antiviral therapy in herpes zoster—
reduces the severity of neuropathic pain. First-line therapy for neuropathic pain includes gabapentin and a tricyclic antidepressent. Neuropathic pain syndromes that result in restricted use of the painful area should be treated with physical therapy and occupational therapy to normalize the active use of the painful extremity.
REFERENCES
1. Hasselström J, Liu-Palmgren J, Rasjö-Wrååk G. Prevalence of pain in general practice. Eur J Pain 2002; 6:375–385.
2. Gilron I, Bailey J, Weaver DF, Houlden RL. Patients’ attitudes and prior treat-ments in neuropathic pain: a pilot study. Pain Res Manag 2002; 7:199–203.
3. Boreau F, Doubrére, Luu. Study of verbal description in neuropathic pain. Pain 1990; 42:145–152.
4. Dworkin RH. An overview of neuropathic pain: syndromes, symptoms, signs, and several mechanisms. Clin J Pain 2002; 18:343–349.
5. Bennett M. The LANSS pain scale: the Leeds assessment of neuropathic symp-toms and signs. Pain 2001; 92:147–157.
6. Young MJ, Boulton AJ, MacLeod AF, Williams DR, Sonksen PH. A multicentre study of the prevalence of diabetic peripheral neuropathy in the United Kingdom hospital clinic population. Diabetologia 1993; 36:150–154.
diabetic neuropathy. Clin J Pain 1998; 14:48–54.
12. Galer BS, Butler S, Jensen M. Case reports and hypothesis: a neglect like syndrome may be responsible for the motor disturbance in reflex sympathetic dystrophy. J Pain Symptom Mange 1995; 10:385–392.
13. Sandroni P, Benrud-Larson LM, McClelland RL, Low PA. Complex regional pain syndrome type I: incidence and prevalence in Olmstead county, a population-based study. Pain 2003; 103:199–207.
14. Stute P, Soukup J, Menzel M, Sabatowski R, Grond S. Analysis and treatment of different types of neuropathic cancer pain. J Pain Symptom Manage 2003; 26:
1123–1131.
15. Luciano CA, Pardo CA, McArthur JC. Recent developments in the HIV neuropa-thies. Curr Opin Neurol 2003; 16:403–409.
16. Schifitto G, McDermott MP, McArthur J, et al. Incidence of and risk factors for HIV-associated distal sensory polyneuropathy. Neurology 2002; 58:1764–1768.
17. Moore R, Wong WM, Keruly J, McArthur J. Incidence of neuropathy in HIV-infected patients on monotherapy versus those on combination therapy with didanosine, stavudine and hydroxyurea. AIDS 2000; 14:273–278.
18. Krishnan AM, Rayman G. New treatment for diabetic-neuropathy: symptomatic treatments. Curr Diabet Rep 2003; 3:459–467.
19. Fox A, Gentry C, Patel S, Kesingland A, Bevan S. Comparative activity of the anti-convulsants oxcarbazepine, carbamazepine, lamotrigine and gabapentin in a model of neuropathic pain in the rat and guinea-pig. Pain 2003; 105:355–362.
20. Backonja M, Glanzman RL. Gabapentin dosing for neuropathic pain: evidence from randomized, placebo-controlled clinical trials. Clin Ther 2003; 25:81–104.
21. Dallocchio C, Buffa C, Mazzarello P, Chiroli S. Gabapentin vs. amitriptyline in painful diabetic neuropathy: an open-label pilot study. J Pain Symptom Manage 2000; 20:280–285.
22. Berger A, Dukes E, McCarberg B, Liss M, Oster G. Change in opioid use after the initiation of gabapentin therapy in patients with postherpetic neuralgia. Clin Ther 2003; 25:2809–2821.
23. Haderer A, Gerner P, Kao G, Srinivasa V, Wang GK. Cutaneous analgesia after transdermal application of amitriptyline versus lidocaine in rats. Anesth Analg 2003;
96:1707–1710.
24. Marchand F, Alloui A, Pelissier T, et al. Evidence for an antihyperalgesic effect of venlafaxine in vincristine-induced neuropathy in rat. Brain Res 2003; 980:117–120.
25. Mattia C, Coluzzi F. Antidepressants in chronic neuropathic pain. Min Rev Med Chem 2003; 3:773–784.
26. Meier T, Wasner G, Faust M, et al. Efficacy of lidocaine patch 5% in the treat-ment of focal peripheral neuropathic pain syndromes: a randomized, double-blind, placebo-controlled study. Pain 2003; 106:151–158.
27. Biesbroeck R, Bril V, Hollander P, et al. A double-blind comparison of topical capsaicin and oral amitriptyline in painful diabetic neuropathy. Adv Ther 1995;
12:111–120.
28. Morley JS, Bridson J, Nash TP, Miles JB, White S, Makin MK. Low-dose metha-done has an analgesic effect in neuropathic pain: a double-blind randomized con-trolled crossover trial. Palliat Med 2003; 17:576–587.
29. Watson CP, Moulin D, Watt-Watson J, Gordon A, Eisenhoffer J. Controlled-release oxycodone relieves neuropathic pain: a randomized controlled trial in painful diabetic neuropathy. Pain 2003; 105:71–78.
30. Wassilew SW, Wutzler P, Wutzler P. Oral brivudin in comparison with acyclovir for herpes zoster: a survey study on postherpetic neuralgia. Antiviral Res 2003;
59:57–60.
31. Bowsher D. The effects of pre-emptive treatment of postherpetic neuralgia with amitriptyline: a randomized, double-blind, placebo-controlled trial. J Pain Symp-tom Manage 1997; 13:327–331.
32. Pappagallo M, Haldey EJ. Pharmacological management of postherpetic neural-gia. CNS Drugs 2003; 17:771–780.
33. DeBeneditis G, Lorenzetti A. Topical aspirin/diethyl ether mixture versus indo-methacin and diclofenac/diethyl ether mixture for acute herpetic neuralgia and postherpetic neuralgia: a double-blind, cross-over placebo controlled study. Pain 1996; 65:45–51.
34. Chung OY, Bruehl SP. Complex regional pain syndrome. Curr Treatment Options Neurol 2003; 5:499–511.
b. Decreased hair growth c. Tremor
d. Nail deformities e. All of the above
3. Postherpetic neuralgia can be reduced by treating herpes zoster early with:
a. Antiviral agents b. Amitriptyline c. Opioids d. A and B e. All of the above
4. First-line therapy for neuropathic pain includes:
a. 5% lidocaine patches b. Venlafaxine c. Gabapentin d. Low-dose opioids e. All of the above
131
From: Chronic Pain: A Primary Care Guide to Practical Management Edited by: D. A. Marcus © Humana Press, Totowa, NJ