Newer guidelines for treatment of neuropathic pain Gautam das

Treatment guidelines Also called clinical practice guidelines Issued by professional or academic bodies Systematically developed statements based on available evidence to help clinicians in making decision High quality evidence may be lacking Geographical variation should be there

What is neuropathic pain? Nociceptive pain: Pain that arises from actual or threatened damage to non- neural tissue and is due to the activation of nociceptors. Neuropathic pain: Pain caused by a lesion or disease of the somatosensory nervous system.

Features of neuropathic pain Burning sensation Tingling sensation, crawling of ant sensation Change of temperature increase pain Touch increases pain Feeling of numbness in area of pain Electric shock like pain Little pressure increases pain Radiation of pain

How to diagnose neuropathic pain? Bedside diagnosis: Neuropathic Pain Questionnaire (NPQ) ID Pain  PainDETECT  The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) Douleur Neuropathique en 4 Questions (DN4)

Investigations to diagnosis of neuropathic pain Quantitative sensory testing (QST) Quantitative Sudomotor Axon Reflex Testing (QSART) Skin biopsy NCS/ EMG

Outline of management Pharmacotherapy Non-pharmacological treatment Interventional management

Pharmacological management Antidepressants Anticonvulsants Na channel blockers Capsaicin Opioids Canabinoids

interventions Intravenous therapies (Ketamine, Lidocaine) Sympathetic blocks Pulsed RF Conventional RF Spinal Cord Stimulation

systematic review OF Clinical practice guidelines for the management of neuropathic pain

All Neuropathic Pain (Excluding Trigeminal Neuralgia)

Step 1. Amitriptyline Start at 10mg at night, increase by 10mg every 3-7 days according to effect & tolerability Usual Therapeutic Dose Range: 25-75mg at night There is limited evidence of effectiveness of doses >75mg (use only on the advice of pain services)

Amitriptyline cont.… Duration of adequate trial: 6-8 weeks with at least 2 weeks at the maximum tolerated dose Do not stop abruptly Reduce gradually over 4 weeks (or 6 months if taking long term) Contraindicated in arrhythmias, severe liver disease, recent MI & manic phase of bipolar disorder. Can be used in combination with gabapentin or pregabalin if there is a partial response to either or both medications.

Step 2: Gabapentin Start at 300mg at night, titrate upwards until efficacy achieved or not tolerated. Reduced doses required in renal impairment. The rate of increase should be guided by patient & tolerability. Usual Therapeutic Dose Range: 300mg-3600mg daily in three divided doses Duration of adequate trial: 3-8 weeks for titration plus 2 weeks at maximum tolerated dose. Do not stop abruptly. Decrease gradually over 1-2 weeks

Step 3: Pregabalin Start at 75mg twice daily, titrate upwards until efficacy achieved or not tolerated. Reduced doses required in renal impairment. The rate of increase should be guided by patient & tolerability. Usual Therapeutic Dose Range: 150-600mg daily in divided doses Duration of adequate trial: 3-8 weeks for titration plus 2 weeks at maximum tolerated dose. Do not stop abruptly. Decrease gradually over 1-2 weeks

Duloxetine (If diabetic neuropathy) Avoid if CrCl <30ml/minute Start at 60mg daily (a 30mg starting dose may be appropriate for some patients). Increase to 60mg twice daily after 1 week if needed. Duration of adequate trial: 8 weeks with at least 4weeks at maximum tolerated dose. Do not stop abruptly. Decrease dose gradually over 1-2 weeks If the first choice is not tolerated or ineffective, discontinue and try the other drug

Treatment of Trigeminal Neuralgia

Carbamazepine 1st line Start at 100mg twice daily (prescribe generically) Titrate slowly e.g. by 100mg every 3 days to 1600mg in divided doses. (MR preparations may be useful at night if the person experiences breakthrough pain). If there is inadequate response or treatment is not tolerated consider early referral to a specialist pain or condition specific service

Post- Herpetic Neuralgia Treat initially with standard oral therapies as per steps 1-3 and topical capsaicin (unless contra-indicated or not tolerated). If standard therapies fail, or lead to intolerable side effects, consider lidocaine 5% medicated plasters, these are approved for primary care initiation when used to treat post-herpetic neuralgia.

TOPICAL TREATMENTS Consider capsaicin cream for patients with localized neuropathic pain who wish to avoid, or who cannot tolerate oral treatments.1 To minimise side-effects start at 0.025% pea size amount four times daily for 6-8 weeks & increase if tolerated to 0.075% four times daily. Duration of adequate trial: Pain relief begins within the 1st week and increases with continuing use, over the next 2-8 weeks

Interventions in neuropathic pain Robert H. Dworkin et al. Interventional management of neuropathic pain: NeuPSIG recommendations. Pain. 2013; 154(11): 2249–2261. Van zundert et al. Evidence based interventional pain practice according to clinical diagnosis. Pain practice. 2011; 11(5) 423-429.

Herpes zoster Epidural or paravertebral nerve block(s) for treatment of pain Quality of Evidence: Moderate Strength of Recommendation: Weak Provides relief of acute pain, but has not been compared against less invasive treatments, such as oral pharmacotherapy

Wip recommendation

WIP Algorithm FOR DPN Diabetic polyneuropathy Exclude other causes of neuropathy Conventional medical management of diabetes Optimal pharmacological management with (combination of) anti-neuropathic pain drugs Consider spinal cord stimulation in treatment resistant cases (Recommendation: 2C+)

WIP algorithm for BRACHIAL PLEXUS INJURY Painful brachial plexus lesion Rehabilitation ± pharmacological management Surgical reconstruction for nerve lesion Consider DREZ (dorsal root entry zone) lesion for severe persistent pain Consider spinal cord stimulation Motor cortex/ Brain stimulation (Recommendation: 0)

WIP RECOMMENDATION FOR RADICULOPATHY Interlaminar corticosteroid injection 2B+/- TF steroid injection in contained herniation 2B+ TF steroid injection in extruded herniation 2B- RF lesioning at the level of the spinal DRG 2A- PRF at DRG 2C+

WIP RECOMMENDATION FOR FBSS Spinal Cord stimulation in FBSS 2A+ Adhesionolysis by epiduroscopy in FBSS 2B+

WIP RECOMMENDATION FOR CRPS Intravenous Regional block with Guanethidine 2A- Stellate ganglion block 2B+ Lumber Sympathetic block Brachial plexus block 2C+ Epidural infusion analgesia Spinal Cord Stimulation Peripheral nerve Stimulation

WIP RECOMMENDATION FOR TRIGEMINAL NEURALGIA Radiofrequency treatment of Gasserian ganglion (Conventional/Thermal) 2B+ Pulsed RF treatment Gasserian ganglion 2B-

summary Neuropathic pain is difficult to diagnose and treat Pharmacotherapy is main form of treatment Interventions have limited role, can be considered in refractory cases Recent practice guidelines must be followed for both pharmacological and interventional treatment We need Indian guidelines for our own population group