Trigeminal neuralgia is a pain in the face, usually unilateral, occasionally bilateral, and is one of the most common neuralgic pains in the elderly. The incidence rises gradually with age. Trigeminal neuralgia causes a sharp stabbing pain in the cheek, lower face or around the eye. This pain can last from a few seconds to several minutes. The typical trigeminal neuralgia has the following characteristics: 1. The pain is confined to the distribution area of the trigeminal nerve (one side of the face), and is usually seen in the unilateral maxillary branch (frontal) and mandibular branch (perioral paranasal), but is rare in the ophthalmic branch. 2. The pain is sudden and abrupt, with intermittent periods of variable length and more intense attacks, such as cutting, electric shock-like, stabbing pain. 3. Trigger points often exist, and light touching of trigger points can induce pain, and trigger points are usually located near the midline such as the paranasal and perioral areas. In addition, chewing, speaking, brushing teeth, facial contact with cold air, smiling, frowning, making faces, etc. can induce painful episodes. 4. There are no abnormal signs in general, except for a few people who have decreased sensation on the same side. Trigeminal neuralgia has the characteristic that the longer the course of the disease, the more frequent the attacks, and rarely heals itself, which has a greater impact on the daily work and life of patients. Do I need to be examined for trigeminal neuralgia? It may be necessary. By understanding the symptoms and physical examination, the physician should be able to tell if trigeminal neuralgia is present. They will perform a number of other tests to obtain information about the cause. These tests include magnetic resonance imaging (MRI) of the brain or a CT scan. These imaging tests can show images of the brain. Trigeminal neuralgia is divided into two types, primary and secondary, depending on the cause. Primary trigeminal neuralgia is defined as the absence of clinical neurological signs, along with the absence of organic lesions, and accounts for approximately 80% of all trigeminal neuralgia. Currently, it is believed that compression of the trigeminal nerve by blood vessels is the main cause of trigeminal neuralgia. In contrast, secondary trigeminal neuralgia mostly has a clear etiology, such as after herpes virus infection, trauma, multiple sclerosis, intracranial tumor, and vascular malformation. Cranial magnetic resonance imaging (MRI) and trigeminal reflex test are important tests to distinguish primary trigeminal neuralgia from secondary trigeminal neuralgia. How is trigeminal nerve treated? It is usually treated through medication. There are different types of medications that physicians can use to treat trigeminal neuralgia. In most cases, physicians will prescribe a medication that is usually used to prevent seizures, and these medications suppress the nerve signals that cause the pain. Secondary trigeminal neuralgia is treated primarily for the cause. Treatment of primary trigeminal neuralgia is primarily pharmacologic. In the Guidelines for the Treatment of Trigeminal Neuralgia, presented by the American Academy of Neurology in conjunction with the European Federation of Neurology, the drugs carbamazepine and oxcarbazepine are still used as the first-line treatment drugs. Other drugs such as lamotrigine, gabapentin, pregabalin and other antiepileptic drugs and non-antiepileptic drugs such as baclofen and tizanidine can be used as second and third line treatment drugs. However, drug therapy has more adverse effects and the efficacy decreases gradually with long-term drug use. There may be more adverse drug reactions such as nausea, dizziness, ataxia, liver function impairment, and blood cytopenia, which can affect patients’ lives in severe cases. For most patients, medications can help reduce the number of episodes of trigeminal neuralgia and reduce the level of pain in patients. However, if medication does not help much or causes too many side effects, physicians will discuss other treatment options. These options include different types of surgical operations, such as choosing invasive treatments like microvascular decompression, gamma knife radiation therapy, and radiofrequency thermocoagulation of the meningeal ganglion to suppress the nerve and reduce the likelihood of nerve firing. These surgical treatments may help relieve symptoms, but sometimes side effects can occur, including facial numbness or pain. What about patients who cannot tolerate surgery and cannot tolerate the side effects of medication? There is data to support that botulinum toxin injections may be effective for refractory trigeminal neuralgia. A 2014 review of the literature identified 2 small randomized controlled trials evaluating botulinum toxin for trigeminal neuralgia. The largest trial randomly assigned 42 patients who failed pharmacologic treatment of trigeminal neuralgia to 22 in the group receiving botulinum toxin type A and 20 in the placebo group (saline), where the drug was injected into the skin or mucosa at the site of pain. At 12 weeks, patients assigned to the botulinum toxin injection group showed a significant decrease in mean pain score and frequency of pain episodes compared to the placebo group. In addition, the number of effective patients (defined as a 50% or greater reduction in pain scores) was significantly greater in the botulinum toxin injection group than in the placebo injection group (68% versus 15%). This is a double-blind controlled clinical study and is a Level 1 study. Carlos injected botulinum toxin type A at doses ranging from 20 U to 50 U into the painful areas and trigger points of 12 patients with primary trigeminal neuralgia and found that 10 patients experienced pain relief within minutes of injection. Previously, 11 of these 12 patients were taking antiepileptic drugs and 4 had undergone surgical treatment, but none of them could effectively relieve the pain, which was a case of refractory trigeminal neuralgia. Therefore, botulinum toxin type A injections can be tried for the treatment of refractory trigeminal neuralgia. Botulinum toxin type A treatment for trigeminal neuralgia is generally safe, with mild and reversible side effects. Side effects include facial asymmetry, stiffness of facial muscles, bruising and edema at the injection site after botulinum toxin injection treatment. The side effects are usually self-limiting and usually resolve on their own within 1 to 3 weeks.