Trigeminal neuralgia (TN) is a neuropathic pain that occurs in the area innervated by the trigeminal nerve. Typical trigeminal neuralgia is characterized by paroxysmal, transient pain attacks, each lasting from a few seconds to several minutes, with severe and unbearable pain, such as burning, stabbing, cutting, tearing, etc. The attacks may be accompanied by facial muscle twitching The pain may be accompanied by twitching of facial muscles and deviation of the corners of the mouth to one side. The pain mostly occurs unilaterally, and there are often trigger points (trigger points) along the trigeminal nerve distribution area, such as upper and lower lips, corners of the mouth, gums, tongue, nose, etc. It can be triggered when washing the face, brushing teeth, drinking, talking, shaving, which seriously affects the patient’s daily life. The interval between pain episodes is as normal, the interval is long in the early stage of onset, and then gradually shortened, and in severe cases, one attack in several minutes, or even develop into persistent pain, and the pain cannot be relieved naturally without treatment. Neurological examination mostly has no positive signs. The diagnosis of trigeminal neuralgia mainly relies on clinical manifestations, and imaging examinations such as CT and MRI are mainly used to exclude secondary trigeminal neuralgia. Trigeminal neuralgia is usually classified into typical and atypical, and also into primary and secondary, and the former classification is currently closely related to the choice of treatment plan and surgical efficacy in clinical practice. Therefore, the diagnostic criteria for typical and atypical trigeminal neuralgia are presented here. Diagnostic criteria of typical trigeminal neuralgia: (1) paroxysmal pain in the distribution area of the trigeminal nerve; (2) pain is paroxysmal, each attack lasts from a few seconds to several minutes, and the intervals are completely normal; (3) pain is lightning-like, electric shock-like, or electroshock feeling intense and unbearable, and can be induced when washing the face, brushing teeth, drinking, talking, or even wind blowing; (4) in the areas where sensory endings are concentrated (such as the upper and lower lips, the corners of the mouth, gums, tongue, nose, etc.); (5) in the early stage of the disease, carbamazepine treatment is effective; (6) neurological examination mostly has no positive signs. Diagnostic criteria for atypical trigeminal neuralgia: (1) severe pain in the distribution area of the trigeminal nerve; (2) frequent episodes of pain, intermittent pain, or even persistent pain; (3) diverse nature of pain, which is difficult for patients to describe, but can be induced to worsen when washing the face, brushing teeth, drinking water, or speaking; (4) absence of trigger point phenomenon in most patients; (5) presence of facial numbness, skin coarseness and hyperalgesia; (6) neurological examination may show superficial hyperalgesia of the affected skin. The diagnosis of typical trigeminal neuralgia is not difficult clinically, but the diagnosis of atypical trigeminal neuralgia requires differentiation from a variety of diseases, such as dental pain, temporomandibular joint pain, migraine, glossopharyngeal neuralgia, pterygopalatine neuralgia, and median neuralgia. The specific points of differentiation are as follows: 1. extracranial diseases 1. toothache: mostly caused by inflammation, such as gingivitis, periodontitis, hunchbacked teeth, etc., because toothache is often reflected along the trigeminal nerve distribution area to the ipsilateral upper and lower gums and head and face, easily confused with trigeminal neuralgia, typical toothache is paroxysmal pain in the gums and face, late for persistent swelling or throbbing pain, teeth are sensitive to hot and cold, can be triggered after stimulation, oral examination can be seen Gingival redness and swelling, restricted mouth opening, percussion pain, and the pain disappears after dental examination and treatment. 2.Temporomandibular joint pain: mostly caused by temporomandibular arthritis, temporomandibular joint dysfunction, pain is limited to the temporomandibular joint area, pain is continuous, related to the movement of the mandibular joint (mouth opening, chewing), jaw movement is limited, mouth opening with popping sound, local pressure pain. Patients with rheumatism and rheumatoid rheumatism may have elevated blood sedimentation, anti-“O” and rheumatoid factor, etc. X-ray radiographs may show blurring and narrowing of the temporomandibular joint space and osteoporosis, etc. 3.Migraine: unilateral headache caused by imbalance of vasodilation and contraction, with pain aura such as irritability, blurred vision, nausea, vomiting, etc. The location of pain is mostly in the branch area of external carotid artery (such as superficial temporal artery, occipital artery), with throbbing throbbing pain and swelling pain, lasting for hours or even days, aggravated by emotional tension or fatigue, and effective with oral non-steroidal analgesics (aspirin, fenbid, etc.). 4, paranasal sinusitis: facial pain can be caused by inflammation of maxillary sinus, septal sinus, frontal sinus, etc. The degree of pain is related to the change of body position, and is a persistent distension, dull pain, no trigger point, pain is not fixed on the unilateral face. Paranasal sinus drainage surgery can cure, and X-ray or thin CT cranial scan can help in differential diagnosis. 2. cranial neuralgia 1. glossopharyngeal neuralgia: the incidence is lower than trigeminal neuralgia, the pain site is at the root of the tongue, pharynx and tonsils, often triggered when eating, swallowing and speaking, and needs to be distinguished from trigeminal neuralgia (branch III). 2. Intermediate neuralgia: the pain site is mainly located in the ear, and it is not painful when chewing, speaking or swallowing. It can be induced by percussion of the facial nerve, which may be related to viral infection of the facial nerve or compression of the facial nerve by blood vessels, and the effect of oral carbamazepine is not good. 3.Pterygopalatine neuralgia: the pain is located in the deep part of the face and can be radiated to the root of the nose, cheek, maxilla, orbit, mastoid, ear, occiput and shoulder, with pressure pain around the orbit, burning pain or swelling pain, paroxysmal or continuous pain, nasal mucous membrane congestion, conjunctival congestion, nasal congestion and lacrimation during the attack. Pterygopalatine ganglion closure is effective. 4, atypical facial neuralgia: it may be related to sympathetic nervous system dysfunction, mostly seen in young adults, pain is not distributed along the nerve, pain is more diffuse, deeper, not easy to locate, no trigger point, longer duration, the attack is accompanied by sympathetic nervous system symptoms such as lacrimation, facial flushing, nasal mucosal congestion, etc., with vasoconstriction or non-steroidal analgesics are often effective. 5. Inflammation of trigeminal nerve: mostly caused by viral infection, diabetes, etc. resulting in demyelinating lesions of trigeminal nerve, the pain is persistent and can be unilateral or bilateral pain in the area of trigeminal nerve innervation, hyperalgesia of trigeminal nerve sensory function, or accompanied by trigeminal nerve motor dysfunction. Secondary trigeminal neuralgia 1. Benign tumors in the pontocerebellar horn region: cholesteatoma, trigeminal nerve sheath tumor, auditory neuroma, meningioma, hemangioma, etc. In addition to trigeminal neuralgia symptoms, they may be accompanied by facial hyperalgesia, facial and auditory nerve involvement to facial palsy, hearing loss, vertigo and other symptoms, cerebellar and brainstem compression symptoms. CT and MRI examination of the head is an important diagnostic basis. 2.Cranial base malignant tumor: nasopharyngeal carcinoma or other metastatic carcinoma invades the skull base, destroys the bone, and the tumor compresses and infiltrates the trigeminal nerve, which causes persistent severe pain, and the tumor invades the cranial nerve such as the actinic nerve, the talocrural nerve and the facial nerve, which can cause corresponding symptoms, such as facial numbness, diplopia and facial paralysis. CT and MRI examination of the head can help to differentiate. Four, thalamic pain: mostly due to stroke (cerebral hemorrhage, cerebral infarction) caused by thalamic damage to one side of the face pain, pain for continuous dull pain, burning-like pain, no obvious trigger point, carbamazepine can not relieve pain. The patient has a history of stroke, and cranial CT and MAI help in the differential diagnosis.