Neuralgia - Pathophysiology

Pathophysiology

Neuralgia is often difficult to diagnose, and most treatments show little or no effectiveness. Diagnosis typically involves locating the damaged nerve by identifying missing sensory or motor function. This may involve tests such as an EMG test or a nerve conduction test. Neuralgia is more difficult to treat than other types of pain because it does not respond well to normal pain medications. Special medications have become more specific to neuralgia and typically fall under the category of membrane stabilizing drugs or antidepressants such as Cymbalta. The antiepileptic medication(AED) Lyrica (pregabalin) was developed specifically for neuralgia and other neuropathic pain as a successor to Neurontin (gabapentin).

Under the general heading of neuralgia are trigeminal neuralgia (TN), atypical trigeminal neuralgia (ATN), occipital neuralgia, glossopharyngeal neuralgia and postherpetic neuralgia (caused by shingles or herpes). The term neuralgia is also used to refer to pain associated with sciatica and brachial plexopathy.

In the case of trigeminal neuralgia the affected nerves are responsible for sensing touch, temperature sensation and pressure sensation in the facial area from the jaw to the forehead. The disorder generally causes short episodes of excruciating pain, usually for less than two minutes and usually only one side of the face. The pain can be described in a variety of ways such as "stabbing," "sharp," "like lightning," "burning," and even "itchy". In the atypical form of TN, the pain presents itself as severe constant aching along the nerve. The pain associated with TN is recognized as one of the most excruciating pains that can be experienced.

Simple stimuli such as eating, talking, making facial expressions, washing the face, or any light touch or sensation can trigger an attack (even the sensation of a cool breeze). The attacks can occur in clusters, as an isolated attack, or be completely constant. Some patients will have a muscle spasm which led to the original term for TN of "tic douloureux" ("tic", meaning 'spasm', and "douloureux", meaning 'painful', in French).

Neuralgia is a form of chronic pain and can be extremely difficult to diagnose. Postherpetic neuralgia is the easiest to diagnose because it follows an obvious cause (shingles). Neuralgia is a rare disease. Women are more likely to be affected than men. In some cases, multiple sclerosis is related to nerve damage, causing the pain, so doctors will likely ask about family history to help diagnose. Nothing unusual can be seen in brain scans, so diagnosis is usually based on the description of the symptoms and the response to the medication or procedures.

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