[MUSIC] Welcome, in this segment we will be discussing Trigeminal Neuralgia, a common type of neuropathic pain condition encountered in clinical practice. This condition has also been referred to as Tic Douloureux. Let's review some facts and figures regarding Trigeminal Neuralgia. The general prevalence of this condition is 0.01% to 0.03%. Does this mean you will see high volumes of patients with this condition? That is unlikely based on these numbers, but individuals with this disorder often make their presence known to healthcare providers as they experience severe, debilitating pain that significantly affects their daily activities. Females are more commonly affected with this condition than males in nearly a two to one ratio. If you recall from our previous discussion females are also more commonly affected by TMDs compared to males. Typically, onset of Trigeminal Neuralgia is greater than 40 years of age, with peak incidents between 50 to 60 years of age. Therefore, depending on the age of the typical patient population in a healthcare practice, there may be more frequent encounters with patients suffering from Trigeminal Neuralgia. Most cases of Trigeminal Neuralgia are considered classic as they present with classic signs and symptoms that the astute clinician will identify as clinically consistent with this condition. Also, the most commonly identified ideology for classic Trigeminal Neuralgia is vascular compression of the Trigeminal nerve route within the brain. Alternatively, many cases of classic Trigeminal Neuralgia are considered idiopathic, as a specific ideology is never identified. What are the signs and symptoms of classical Trigeminal Neuralgia? Patients often complain of excruciating pain associated with this condition. This is the type of pain that often stops an individual in the middle of an activity due to symptom severity. Electric like pain and or a lightning bolt sensation are common descriptors of pain associated with Trigeminal Neuralgia. Contrast this with TMD pain, which patients often describe as dull, achy, or fatigue like. If a patient describes electric shock like pain, the clinician should consider Trigeminal Neuralgia near the top of their differential diagnosis. Trigger areas or zones are another feature of classic Trigeminal Neuralgia. Patients may report that pain is triggered by something lightly touching the specific area on their face. Any type of light pressure applied to the outside of the face that may trigger Trigeminal Neuralgia pain is considered an extraoral trigger. Intraoral trigger zones may be present either as the only area that stimulates pain or in combination with extraoral trigger zones. Toothbrushing or eating may stimulate gingival or mucosal trigger areas, resulting in debilitating pain and avoidance or cessation of routine activities. Episodes of Trigeminal Neuralgia pain are typically of short duration, lasting seconds to minutes. A feature specific to Trigeminal Neuralgia is latency. This refers to the period of time of pain stimulation and experiencing the pain sensation. Clinicians should ask patients about latency as it aids in correctly diagnosing this condition. Patients with Trigeminal Neuralgia often experience multiple episodes of pain throughout the day. Another important clinical feature highly suggestive of Trigeminal Neuralgia is refractory period. This refers to the inability to stimulate pain immediately after a pain episode has finished even if a triggers zone is touched. As with latency, clinician should ask patients if they experienced a refractory period if Trigeminal Neuralgia is suspected, as it will help confirm the diagnosis. Trigeminal Neuralgia typically affects one side of the face. This is referred to as a unilateral presentation. In rare cases, Trigeminal Neuralgia can affect both sides of the face or have a bilateral presentation, but the vast majority of these cases are unilateral. Any branch of the trigeminal nerve may be affected in this condition, but the most common nerve branches affected are the Maxillary, or V2. And Mandibular or V3 branches. Therefore, patients with Trigeminal Neuralgia most commonly experience pain in the middle one third and or lower one third of the face. If a patient presents with a facial pain complain this is suspicious for Trigeminal Neuralgia, it is important for clinicians to complete an appropriate evaluation to determine if this is the correct diagnosis. The first component of a evaluation is to understand patient reported symptoms. We have discussed the signs and symptoms of that Trigeminal Neuralgia that should alert the clinician to this possible diagnosis. A cranial nerve examination should be conducted for any patient with suspected Trigeminal Neuralgia. It is important to complete this exam in a thorough and systematic manner. If any abnormal findings are detected on examination of the cranial nerves the patient should be promptly referred to an appropriate healthcare provider for further evaluation and management. An appropriate physical exam should be conducted for patients with suspected Trigeminal Neuralgia. Clinicians should attempt to identify extra-oral and/or intra-oral trigger zones which stimulate pain. In addition, a thorough evaluation of the salivary glands, oral cavity, and dentition should be performed to rule out any pathology attributed to these structures that may be a source of the patient's pain. Many clinicians also perform a TMD examination to rule out these disorders as a source of pain. Dental imagining such as periapical and panoramic radiographs are used to rule out dental sources of pain as well as local pathology affecting the maxilla and mandible that may be a source of pain. Central nervous system, or CNS imaging, is commonly used for evaluating patients with suspected Trigeminal Neuralgia. The use of MRI and MRA, magnetic resonance angiography, are used to rule out vascular compression of the trigeminal nerve root, as well as other types of CNS pathology that may be the etiology of the patient's condition. Therapy for Trigeminal Neuralgia can be considered in two categories: medical and surgical. The vast majority of patients with this condition will undergo medical management as first line therapy for this condition. The medication used most frequently to manage Trigeminal Neuralgia is Carbamazepine. This is an anticonvulsant agent that effects sodium channels to modulate nerve function. The effective dose of Carbamazepine for Trigeminal Neuralgia is between 200 milligrams and 1200 milligrams daily. Patients may experience significant side effects while using this medication, including mild to severe skin rashes, and alterations of bone marrow and liver function. In addition, this drug has potential for interactions with several other medications, due to it's effect on drug metabolizing enzymes. Due to it's effect on specific organ systems, it is advisable for clinicians to manage Trigeminal Neuralgia patients with this medication to obtain base line and periodic laboratory evaluations to monitor bone marrow and liver function. In addition, patients should be made aware of potential side effects of this medication and should be instructed to contact their healthcare provider if they experience any side effects. Oxcarbazepine is another anticonvulsant that is frequently used to manage Trigeminal Neuralgia, although scientific data to support its use for this purpose is more limited compared to Carbamazepine. This is considered a structural derivative of Carbamazepine with decreased potential for side effects and interactions with drug metabolizing enzymes. Effective doses of Oxcarbazepine for management of Trigeminal Neuralgia range from 300mg to 1800mg daily. Other anti convulsionations used to manage Trigeminal Neuralgia include Lamotrigine, Baclofen, Phenytoin, Gabapentin and Pregabalin. These may be used as monotherapy or in combination. All of these agents must be carefully titrated for maximal benefit and effective dosages differ for each medication in conjunction with individual variability. All have potential for significant side effects and patients using these medications must be closely monitored by the appropriate health care provider. Most patients experience significant symptom relief initially with medical therapies, but long term results are mixed. Patients who do not respond to medical therapy may require surgical treatment for management of Trigeminal Neuralgia. Surgical procedures can be divided into two categories, peripheral and central. There are several types of peripheral procedures that may be attempted to manage this condition. Neurectomy involves surgical manipulation and/or removal or peripheral nerves that have been identified as a source of pain. Cryotheraphy involves freezing peripheral nerves with a cryoprobe containing a refrigerant, while injections of alcohol and/or glycerol in the vicinity of affected peripheral nerves may help to modify nerve impulses resulting in decreased pain. The risk of developing neuropathic pain is increased with peripheral procedures and only health care providers with extensive training and experience should be consulted for consideration of these types of procedures. The long term results to peripheral procedures in the management of Trigeminal Neuralgia are considered next to poor. Overall, central procedures appear to be more successful than peripheral procedures from management of Trigeminal Neuralgia. Microvascular decompression, or MVD, is the most common central surgical procedure for management of this condition with the highest rate of long term success compared to other central procedures. As previously discussed a common cause of Trigeminal Neuralgia is vascular compression of the trigeminal nerve root in the brain. MVD involves separation of intra-cerebral arteries from the trigeminal nerve root which often yield substantial to complete resolution of pain symptoms. Gamma knife surgery is another central procedure that has demonstrated effectiveness for the management of the Trigeminal Neuralgia. With this procedure, treatment is aimed at delivering precise radiation beams to the trigeminal nerve root, at the point of vascular compression. One of the benefits of gamma knife surgery is that it does not require a surgical incision, which is required for MVD procedures. Other destructive procedures aimed at the trigeminal nerve root include various types of rhizolysis. This may be accomplished via glycerol injections, radio frequency, thermal coagulation and balloon compression. It is highly recommended to consult with a neurosurgeon with extensive training and experience with these procedures if central surgical management is warranted. This concludes our discussion of Trigeminal Neuralgia. In the next segment we will discuss persistent idiopathic facial pain, another type of neuropathic pain disorder.
