Neuropathic Pain: What Can We Do?

Neuropathic pain is a diagnosis of mechanism, not a synonym for burning or tingling. In the acute care setting, altered sensation on exam and a central-versus-peripheral differential matter more than pain adjectives, and first-line treatment is usually antidepressant-class therapy rather than gabapentin.

Diagnosing Neuropathic Pain

• Central versus peripheral framing: Separating neuropathic pain into central and peripheral causes sharpens the differential, with stroke, spinal cord injury, and multiple sclerosis on one side and diabetic or post-herpetic neuropathy on the other.
• Pain descriptors alone mislead: Words like burning, tingling, and shooting are not diagnostic; about half of patients with musculoskeletal pain use shooting or tingling language, and roughly 30% describe burning.
• Sensory exam is pivotal: Neuropathic pain should produce altered sensation over the painful area, making the bedside sensory exam more useful than symptom adjectives or screening questionnaires.
• Questionnaire limits: Specialized neuropathic pain questionnaires are only about 80% sensitive and specific, so they support but do not replace a history and focused neurologic exam. We get into the bedside distinctions in the episode.
• High-yield etiologic clues: Post-stroke pain develops in up to 15% of ischemic stroke survivors, and as many as two-thirds of patients with multiple sclerosis develop neuropathic pain, useful context when the complaint is otherwise vague.

Treatment Choices in Acute Care

• Tricyclics as first line: TCAs offer the broadest coverage for neuropathic pain, and the analgesic dose is far lower than the antidepressant dose, with nortriptyline a common starting agent.
• Duloxetine over gabapentin: Duloxetine is a strong first-line option, especially for peripheral neuropathy, while gabapentin is often prescribed beyond the evidence and generally performs less well than TCAs or serotonergic agents.
• Pregabalin for narrow syndromes: Pregabalin has better evidence than gabapentin for selected conditions such as diabetic neuropathy and post-herpetic neuralgia, particularly when the diagnosis is narrow rather than broad.
• Topicals for postherpetic pain: Topical lidocaine is most useful for post-herpetic neuralgia and may be non-inferior to pregabalin, whereas capsaicin can help but is painful to apply.
• Opioids for short flares: Low-dose opioids can be effective for short-term neuropathic pain flares, with addiction risk likely overstated in carefully selected patients. We cover the caveats on the show.
• Combination therapy caution: Second-line treatment often means combining first-line agents, but TCAs and SSRIs should not be paired, and tramadol remains a weak choice supported by low-quality evidence.

References:

1. Peckham AM, et al. Gabapentin use, abuse, and the US opioid epidemic: the case for reclassification as a controlled substance and the need for pharmacovigilance. Risk Manag Healthc Policy. 2018;11:109-116. Published 2018 Aug 17. PMID: 30154674
2. Wiffen PJ, et al. Gabapentin for chronic neuropathic pain in adults. Cochrane Database Syst Rev. 2017;6(6):CD007938. Published 2017 Jun 9. PMID: 28597471
3. Cruccu G, Truini A. A review of Neuropathic Pain: From Guidelines to Clinical Practice. Pain Ther. 2017;6(Suppl 1):35-42. PMID: 29178033