Seminar on neuralgia. neuralgia is a condition of severe nerve pain.

Neuralgia is a condition of nerve pain

1. Neuralgia Prasad . Pharm D 5 th year

2. INTRODUCTION Neuralgia Painful disorder of nerves Pain follows the path of specific nerve Means severe pain in the course of distribution of nerve due to irritation or damage to the nerve TYPES TRIGEMINAL NEURALGIA GLOSSOPHARYNGEAL NEURALGIA POSTHERPETIC NEURALGIA

3. TRIGEMINAL NEURALGIA(TN) Trigeminal Nerve Fifth cranial nerve Supplies sensation to the skin of the face and anterior half of the head TRIGEMINAL NEURALGIA(TN) “It is a condition characterized by sudden, brief and severe recurrent pain which involve the distribution of one or more branch of the fifth cranial nerve.”

4. AETIOLOGY Idiopathic Chemical irritation Inflammation Trauma(including surgery) Compression of nerves by nearby structures Infections

5. PATHOPHYSIOLOGY Ectopic generation of action potentials Compression Demyelination Hyperexcitable Electrically coupled Stimulates Paroxysm of pain

6. EPIDEMIOLOGY 4.5 per 100000 individuals Middle aged and elderly 60% in women Sudden onset and persists for weeks or months before remitting spontaneously Remission may be long lasting but ultimately recurs Mortality

7. CLINICAL FEATURES Paroxysmal attacks of facial or frontal pain lasting for few seconds to minutes Pain occurs in lips, gums, cheeks, chin Sudden, intense, sharp, superficial, stabbing or electric shock like burning Severe pain intensity Precipitation from triggering factors Small area of the face or may spread

8. GLOSSOPHARYNGEAL NEURALGIA GLOSSOPHARYNGEAL NERVE Ninth cranial nerve Sensation to throat and tongue Glossopharyngeal neuralgia Uncommon disorder Severe recurrent pains Begins after age 40 Often in men Cause is unknown

9. CLINICAL FEATURES Attacks are brief, occur intermittently, but cause excruciating pain Triggered by a particular action Begins at back of the tongue or back of the throat, sometimes pain spreads to the ear Lasts for several seconds to a few minutes Affects only one side The pain may radiate to the ear Cardiac symptoms like bradycardia, hypotension and fainting are seen in 1 to 2% of people

10. POSTHERPETIC NEURALGIA Resolution of acute herpes zoster and healing of the zoster rash AETIOLOGY Varicella zoster virus after an attack of herpes zoster (shingles) Manifests after vesicles have crusted over and begun to heal

11. EPIDEMIOLOGY About 20% of patients with herpes zoster 15 times more often in elderly 15 times higher in HIV-infected patients Hodgkin’s lymphoma is about 25%

12. PATHOPHYSIOLOGY After nerve fiber damaged during herpetic zoster infection Damaged nerve fibers cannot send electrical signals Erratic or exaggerated causing chronic, excruciating pain. Persists or recur for months or even years

13. DIAGNOSIS Complete medical history Characteristics and location of pain Physical examination Nerve conduction study WITH Electromyography(NCS/EMG) MRI and CT-SCAN

14. Goals of therapy Reversing or controlling the cause of neuralgia(if identified) Providing pain relief Individualizing the treatment

15. TREATMENT OF NEURALGIA Non-pharmacological Methods Pharmacological Methods Non-pharmacological Methods Surgery Radiation therapy Other types of surgery

16. Micro Vascular Decompression Radiation therapy Multiple rays of high-energy photons concentrated with high accuracy on target nerve root Surgery

17. Other types of surgery Nerve block Cryotherapy Alcohol injection Glycerol injection Neurectomy Peripheral radiofrequency thermocoagulation Balloon compression Electric current

18. PHARMACOLOGICAL TREATMENT Anticonvulsant drugs Tricyclic antidepressants Others -Baclofen -Opioids -Topical Preparations -Botulinum Toxin-A

19. ANTICONVULSANTS Mechanism of action Stabilize abnormal electrical activity in the nervous system caused by injured nerves By decreasing conductance in the sodium channel Inhibits the ectopic discharges

20. Sl No Drugs Initial Dose (mg) Maintenance Dose(mg) Maximum Daily Dose(mg) 1 Carbamazepine 100 200 qid 1200 2 Phenytoin 100 100-400 qd /bid 400 3 Lamotrigine 25 qd 25 bid 500 4 Gabapentin 300 qd 300-900 qd /bid 1200-3600 5 Pregabalin 100qd 300 600

21. Adverse effects Drowsiness, ataxia, dizziness, blurred vision, diplopia, headache, rash, dry mouth, thrombocytopenia

22. LAMOTRIGINE One systematic review found insufficient evidence Effective as an add on therapy PREGABALIN In randomized placebo control trial Greater decrease in pain Improved sleep latency

23. TRICYCLIC ANTIDEPRESSANTS Mechanism of Action Inhibition of serotonin nor adrenaline reuptake opiate receptor or interfere with substance P Anticholinergic effect Sedation

24. TRICYCLIC ANTIDEPRESSANTS (TCAs) Sl No DRUGS DOSE (mg) MAXIMUM DOSE (mg) 1 Amitriptyline 25 qd 150 2 Nortriptyline 25 qd 125 3 Desipramine 25 qd 150 4 Imipramine 25 qd 150

25. Adverse effects Sedation, dry mouth, blurred vision, constipation, weight gain, orthostatic hypotension, urinary hesitancy or retention, reduced gastrointestinal motility

26. OTHERS BACLOFEN Mechanism of action GABA agonist Adverse effects Nausea, vomiting, constipation, diarrhea, rash, hypotension, respiratory depression, muscular weakness, drowsiness, dizziness.

27. Clinical evidence Open label trails and randomized control trails using placebo Baclofen has synergistic action OPIOIDS Mechanism of action Mimic endogenous opioids by activating opioid receptors in the central and peripheral nervous systems

28. Adverse effects Nausea, vomiting, drowsiness, dry mouth, miosis, orthostatic hypotension, constipation, confusion, hallucination, delirium.

29. TOPICAL AGENTS Topical and intradermal agents Lidocaine gel Apply to affected area every 4 to 12 hours as needed Capsaicin cream Apply to affected area 3 to 4 times daily

30. CONCLUSION Neuralgias are chronic affliction Need constant following care Not life-threatening disorders Chances of recurrence Medication adherence Anticonvulsants and TCAs Duration of treatment Elderly and immunocompromised patients

31. Thank you