Treatment of Postherpetic Neuralgia The Journal of Family Practice Carroll Dowden 2002.Volume 51(2) February 2002 pp 121-128E-medicine Author: W Alvin McElveen, MD, Consulting Staff, Department of Neurology, Manatee Memorial Hospital

Ri

Postherpetic NeuralgiaRisk:

1.Advanced age 2.Immunocompromised status 3. Site of HZ involvement Lower risk - Jaw, neck, sacral, and lumbar Moderate risk - Thoracic Highest risk - Trigeminal (especially ophthalmic division), brachial plexusCause: varicella-zoster virus (VZV)

Pathophysiology(1) 1.Abnormal function of unmyelinated

nociceptors and sensory loss (usually minimal) 2.Pain and temperature detection systems

are hypersensitive to light mechanical stimulation, leading to severe pain (allodynia).

Allodynia may be related to formation of new connections involving central pain transmission neurons

Pathophysiology(2)3. Severe, spontaneous pain without allodynia,

possibly secondary to increased spontaneous activity in deafferented central neurons or reorganization of central connections. 4. An imbalance involving loss of large inhibitory

fibers and an intact or increased number of small excitatory fibers has been suggested

IncidenceIn the US: Frequency 1 month after onset of shingles is 9-14.3%; at 3 months, about 5%; at 1 year, about 3%. Internationally:

1.No patient younger than 50 years described severe pain at any time. 2.Patients older than 60 years described severe pain: 6% at 1 month and 4% at 3 months from the onset of shingles.

Data source27 (from 186 trials ) RCTs met inclusion criteria and were reviewed, which were searched

1. MEDLINE (1966~present) 2. Current Contents 3. Cochrane Controlled Trials Registry

The Journal of Family Practice Carroll Dowden 2002.Volume 51(2) February 2002 pp 121-128

The Journal of Family Practice Carroll Dowden 2002.Volume 51(2) February 2002 pp 121-128

The Journal of Family Practice Carroll Dowden 2002.Volume 51(2) February 2002 pp 121-128

The Journal of Family Practice Carroll Dowden 2002.Volume 51(2) February 2002 pp 121-128

ConclusionSix trials of tricyclic anti-depressants found evidence for clinically meaningful effects over 6 weeks. Topical capsaicin 0.075%, gabapentin, and controlled-release oxycodone were shown to be effective, but the clinically meaningful benefit is difficult to quantify. Intrathecal methylprednisolone and possibly bupivacaine sympathetic blocks are helpful in refractory cases. Other treatments evaluated, including topical lidocaine, had no evidence or inconsistent evidence of benefit.

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