- Neuropathic pain assessment
- "pain initiated or caused by a primary lesion or dysfunction of the nervous system"
- Pain >3 months is regarded as chronic
- Nociceptive pain uses the normal pain pathway. Neuropathic pain occurs when there is abnormal activation of these pathways as a result of dysfunction in the nervous system itself.
- Can resolve by itself
- Even traditional nociceptive pain (e.g. OA) can have neuropathic mechanisms
- Causes
- Physical
- Infection
- Ischaemic
- Toxic
- Neoplastic
- Degenerative
- Traumatic (inc. surgery)
- Pain assessment
- History
- Site, radiation, timing, position, associated features, red flags, severity, relieving factors
- Clinical features
- Days anesthesia, burning, tingling, itching, pins & needles, stabbing, shooting pains
- Evoked pains: allodynia (pain from non-painful stimulus), hyperalgesia (exaggerated response to normally painful stimulus). Motor or autonomic involvement (vasomotor or sudomotor)
- Examination
- Skin changes, abnormal sensation, other neurological defecit
- Ix
- MRI, CT, B12, NCS, SSEP, punch Bx
- Assessment tools
- Leeds assessment of neuropathic symptoms and signs (LANSS) - has 5 symptom items and 2 examination ones
- Mechanisms
- Peripheral
- Sensitisation of nociceptors such that there is reduced threshold for activation
- Abnormal neuronal sprouting
- Ectopic firing of Aδ and C fibres in DRG
- Increased expression of Na⁺/Ca²⁺ channels
- Central
- Wind-up
- Loss of central inhibitory mechanisms and enhanced nociceptive input
- Upregulation of NMDA receptors
- CEACCP
Link:ceaccp.oxfordjournals.org/content/8/6/210.full.pdf