Neurology & Pain Medicine & Family Medicine
Neuralgia | Clinique Omicron Quebec
Neuralgia is an intense neuropathic pain that occurs along the course of a sensory nerve or nerve root, resulting from irritation, compression, inflammation, or damage to that nerve. Unlike ordinary nociceptive pain—triggered by direct tissue stimulation and proportional to the intensity of the stimulus—the neuropathic pain of neuralgia is generated by the nervous system itself, in the absence of active tissue damage or disproportionately to any stimulation: it is characterized by distinctive symptoms (burning, electric shock, stabbing, a vice-like sensation, tingling, deep itching) and by hypersensitivity phenomena (allodynia—pain caused by a normally non-painful stimulus such as a light touch, a gentle breeze, or clothing against the skin—and hyperalgesia—an exaggerated pain response to a normally mildly painful stimulus). The term neuralgia is used in a broad sense to refer to any pain of radicular or truncal origin, without necessarily implying a demonstrable anatomical lesion of the nerve—many functional or idiopathic neuralgias show no abnormalities on electromyography, MRI, or laboratory tests. The most common types of neuralgia encountered in clinical practice in Quebec are intercostal neuralgia (post-herpetic or mechanical), lumbosciatic neuralgia (neuralgia of the sciatic nerve at L4-L5-S1), cervicobrachial neuralgia (neuralgia of the brachial plexus at C5-C8-T1), trigeminal neuralgia (see dedicated fact sheet), and pudendal neuralgia. Their management requires precise identification of the etiology—mechanical, infectious, inflammatory, metabolic, or idiopathic—to direct treatment toward the cause when it is modifiable, and toward the relief of neuropathic pain through medications and validated interventions when the cause is irreversible.
Pathophysiological mechanisms of neuropathic pain
- Peripheral sensitization: peripheral nerve lesion → local inflammation → release of algogenic mediators (bradykinin + substance P + NGF + prostaglandins) → lowered activation threshold of peripheral nociceptors → C and A-delta fibers become hyperexcitable and generate ectopic spontaneous discharges at the level of the lesioned axons or dorsal root ganglia (DRG) → spontaneous pain + mechanical allodynia
- Central sensitization: Prolonged bombardment of the dorsal horns of the spinal cord by nociceptive input → NMDA receptor activation → wind-up phenomenon → neuroplasticity of dorsal horn neurons → amplification and maintenance of pain independent of peripheral stimulus + expansion of receptive field (pain spreading beyond the initial nerve territory) → central mechanism of chronic pain persisting after healing of the initial lesion
- Axonal ectopic discharges Focal demyelination (compression + ischemia + inflammation) creates areas of membrane instability → ectopic expression of voltage-gated sodium channels (Nav1.3 + Nav1.7 + Nav1.8) → repeated spontaneous discharges without stimulus → paroxysmal pain in characteristic electrical discharge of neuralgias
- Radicular compression and disc-radicular conflict: The most frequent mechanical mechanism of radicular neuralgia (sciatica + cervicobrachial neuralgia) is a herniated disc compressing a nerve root, leading to radicular ischemia, inflammation from contact with the nucleus pulposus, and segmental demyelination. This results in radiating pain along the dermatome of the compressed root, with sensory and/or motor deficits depending on the severity of the compression.
- Viral reactivation (shingles - VZV): The varicella-zoster virus (VZV) remains latent in the spinal and cranial sensory ganglia after a primary chickenpox infection → reactivation occurs during immunosuppression (age + stress + corticosteroids + chemotherapy + HIV) → viral replication in the sensory ganglion → necrosis and inflammation of the ganglion and the corresponding nerve → metameric vesicular rash (shingles) + acute postherpetic neuralgia → 20 to 30% of patients develop postherpetic neuralgia (PHN) that persists after the rash has healed
Main clinical forms of neuralgia
| Type of neuralgia | Presentation and painful territory | Main causes and specific treatment |
|---|---|---|
| Trigeminal neuralgia (V) | Paroxysmal electric shock-like pain in the V2 distribution (cheek + upper lip + upper teeth) and V3 distribution (jaw + lower teeth) + triggered by light touch (shaving + chewing + speaking) + unilateral + lasting a few seconds + free intervals between attacks (see dedicated file Trigeminal Neuralgia) | Neurovascular compression (CVS) + MS + posterior fossa tumor → carbamazepine or oxcarbazepine first-line + microvascular decompression (Jannetta) if medical resistance |
| Intercostal neuralgia | Burning or band-like pain along the course of an intercostal nerve, unilateral, following the dermatome (intercostal space + hemithorax), worsened by deep inspiration + coughing + trunk movements, cutaneous hyperesthesia or allodynia in the painful area, can mimic visceral pain (MI + pleurisy + abdominal pathology). | Intercostal shingles (most common cause) + chest trauma + rib fracture + chest surgery (post-thoracotomy neuralgia) + thoracic disc herniation + vertebral metastasis + idiopathic → antiviral treatment for acute shingles + tricyclic antidepressants + gabapentin + topical lidocaine or capsaicin cream + lidocaine patch 5 % (Versatis®) |
| Postherpetic neuralgia (PHN) | Persistence or recurrence of neuropathic pain in the shingles-affected area more than 3 months after the vesicular rash has healed + persistent burning sensation + intense cutaneous allodynia (unbearable sensation from clothing contact) + paradoxical coexistence of hypoesthesia and allodynia in the same area + prevalence among the elderly (more than 60% of cases in those over 70) | Primary prevention: shingles vaccination (Shingrix®—2 doses recommended for those aged 50 and older in Quebec) + early antiviral treatment for shingles (valacyclovir 1 g × 3 times daily for 7–10 days) reduces the risk of postherpetic neuralgia (PHN) + treatment for established PHN: amitriptyline + duloxetine + gabapentin + pregabalin + lidocaine patch 5 % + capsaicin patch 8 % (Qutenza®) |
| Lumbar sciatica (sciatic neuralgia L4-L5-S1) | Pain radiating from the buttock to the posterior (S1) or posterolateral (L5) aspect of the lower limb down to the foot + paresthesia or hypesthesia in the affected dermatome + diminished or absent Achilles reflex (S1) + weakness of foot extensors (L4-L5) + motor deficit may be associated + positive Lasègue's sign (pain triggered by straight leg raise) | Herniated disc L4-L5 or L5-S1 (most common cause) + lumbar spinal stenosis + spondylolisthesis + vertebral tumor or metastasis + epidural abscess → conservative treatment as first-line therapy (NSAIDs + paracetamol + physiotherapy) + periradicular corticosteroid injection if failure + discectomy if motor deficit or prolonged resistance |
| Cervicobrachial neuralgia (C5-C8) | Neck pain radiating into the arm, forearm, and fingers depending on the affected root, with paresthesias in the corresponding dermatome: C6 → thumb, C7 → middle finger, C8 → little finger. Spurling's sign (rotation, extension, and lateral flexion of the cervical spine towards the painful side) reproduces or worsens the pain. | Cervical disc herniation (C5-C6 or C6-C7, the most common) + uncoarthrosis + cervical foraminal stenosis + cervical tumor → conservative treatment (soft cervical collar + NSAIDs + physical therapy) + cervical foraminal corticosteroid injection + cervical discectomy with fusion or prosthetic disc if resistant |
| Pudendal Neuralgia | Chronic neuropathic pain in the pudendal nerve territory (perineum + genitals + anal region) + burning + pressure + electric shock + aggravated by sitting + relieved by standing or lying down + often associated with painful intercourse + urinary or defecatory disorders + underdiagnosed | Pudendal nerve entrapment in Alcock's canal (pelvic surgery + childbirth + intensive cycling) + idiopathic → diagnostic and therapeutic pudendal nerve block + pelvic physical therapy + amitriptyline + gabapentin |
| Meralgia Paresthetica | Hypoesthesia, burning, and tingling on the anterolateral aspect of the thigh, without muscle weakness or diminished patellar reflex, related to compression of the lateral femoral cutaneous nerve under the inguinal ligament. | Obesity + pregnancy + wearing a too-tight belt + prolonged standing → correction of causal factor + weight loss + NSAIDs + gabapentin + local corticosteroid injection |
ℹ️
Postherpetic neuralgia is the most debilitating complication of shingles and is one of the most difficult chronic pain conditions to treat. The best way to manage it is through prevention via the shingles vaccine: The Shingrix® vaccine (2 doses administered 2 to 6 months apart) is recommended for everyone aged 50 and older in Quebec, regardless of whether they have previously had shingles, and reduces the risk of shingles by 90% and the risk of postherpetic neuralgia by 89% in vaccinated individuals. The vaccine is covered by RAMQ for certain categories of immunocompromised individuals in Quebec.
Neuropathic pain treatment
The pharmacological treatment of neuralgia aims to reduce central and peripheral neuronal hyperexcitability. First and second-line validated agents are common to most types of neuralgia:
- Tricyclic antidepressants (amitriptyline + nortriptyline) — first-line: Sodium channel blockade + inhibition of serotonin and norepinephrine reuptake (modulating descending inhibitory pain pathways) + amitriptyline 10 to 75 mg at bedtime (lower dose than for depression) + effective on burns + allodynia + associated insomnia + adverse effects: dry mouth + constipation + drowsiness + risk of falls in the elderly + ECG beforehand if known heart disease
- Serotonin-norepinephrine reuptake inhibitors (SNRIs) — first-line: duloxetine (Cymbalta®) 30 to 60 mg/morning + venlafaxine 75 to 225 mg/day + mechanism: reinforcement of descending noradrenergic and serotonergic inhibitory pathways + duloxetine approved by Health Canada for diabetic peripheral neuropathic pain + fewer anticholinergic effects than TCAs
- Gabapentinoids — first line: gabapentin (Neurontin®) 300 to 3,600 mg/day in 3 divided doses + pregabalin (Lyrica®) 75 to 600 mg/day in 2 divided doses + mechanism: binds to the α2δ subunit of voltage-dependent calcium channels → reduced release of glutamate and substance P in spinal nociceptive synapses + effective for burns + electrical shocks + paresthesias + adverse effects: somnolence + dizziness + edema
- Topical treatments — first-line for localized neuropathic pain: 5% lidocaine patch (Versatis®) → local sodium channel blockade → effective for trigeminal neuralgia (TN) and localized intercostal neuralgia + 8% capsaicin patch (Qutenza®) → desensitization of TRPV1 nociceptors + 1 application every 12 weeks by a healthcare professional → proven efficacy in trigeminal neuralgia and HIV-associated neuropathy + EMLA cream (lidocaine + prilocaine) for outpatient use
- Opioids — third line (except severe acute neuralgia): tramadol 50 to 400 mg/day (weak opioid agonist + SNRI) + strong opioids (oxycodone + morphine) as a third-line treatment if first and second lines are insufficient + risk of dependence + side effects + to be used with caution in chronic neuropathic pain
- Non-pharmacological interventions: physical therapy (mobilization + manual techniques + TENS electrostimulation) + neuromodulation (spinal cord stimulation for refractory neuralgias) + interventional techniques (nerve block + periradicular corticosteroid injection for sciatica and cervicobrachialgia) + cognitive-behavioral psychotherapy (CBT) for the psychological component of chronic pain
Situations requiring urgent medical assessment
Seek immediate emergency care if radiating limb pain is accompanied by rapid muscle weakness (difficulty lifting foot + inability to walk on tiptoes or heels + grip weakness) + progressive loss of sensation + or sphincter dysfunction (urinary or fecal incontinence + urinary retention) — these signs suggest cauda equina syndrome (urgent multi-radicular compression requiring emergency surgical decompression within hours) or cervical spinal cord compression with myelopathy.
Chest pain radiating with a unilateral dermatomal vesicular rash (shingles) should lead to a prompt medical consultation to start antiviral treatment (valacyclovir) within 72 hours of the rash, after which the effectiveness in preventing postherpetic neuralgia is significantly reduced.
For the evaluation of neuralgia, the prescription of an appropriate etiological workup, the initiation of pain management treatment, and referral to neurology, orthopedics, or pain medicine depending on the type of neuralgia, Clinique Omicron offers medical consultations at its service points in Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
Consult at Clinique Omicron
Clinique Omicron's physicians and nurse practitioners (NPs) assess patients with pain along a nerve or nerve root pathway, prescribe appropriate additional tests (spinal MRI + EMG + biological workup depending on suspected etiology), initiate neuropathic pain treatment (amitriptyline + duloxetine + gabapentin + topical treatments), and refer to appropriate specialties (neurology + orthopedics + pain medicine + infectious diseases for shingles) based on the type and severity of neuralgia. Consultations are available at several service points in Quebec and via telemedicine. To make an appointment, visit cliniqueomicron.ca.
The content of this page is provided for informational purposes only and does not substitute for the advice of a physician or a specialist in pain medicine or neurology. Any neuralgia with progressive motor deficit, sphincter disorders, or suspected spinal cord compression constitutes a neurosurgical emergency requiring immediate hospital evaluation.
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