(i) Overview
Trigeminal neuralgia (also known as painful twitching) is mainly manifested by episodes of severe pain in the distribution area of the facial trigeminal nerve; slightly more in women, mostly starting after middle age and increasing with age; the pain site is often located unilaterally, with the right side being more common; the distribution is most common in the distribution area of the Ⅱ and Ⅲ branches of the trigeminal nerve, and pain in the Ⅰ branch alone is rare.
(ii) Classification
(1) Primary trigeminal neuralgia refers to those with clinical symptoms, and various examinations do not reveal organic or functional lesions related to the onset of the disease.
(2) Secondary trigeminal neuralgia is trigeminal neuralgia caused by definite lesions, and the common lesions are: (1) certain tumors, vascular malformations, aneurysms and arachnoiditis located in the pontocerebellar horn and middle cranial fossa, among which epidermoid cysts in the pontocerebellar horn are the most common; (2) abnormal bone development such as elevated rock crest, narrowing of the foramen or foramen ovale; (3) inflammation of the trigeminal nerve, multiple sclerosis, certain organic lesions in the brainstem or thalamus .
(iii) Diagnosis
(1) Clinical manifestations of primary trigeminal neuralgia
(1) The nature of pain is sudden lightning-like attacks without aura, in the form of cutting, burning, pinprick or electric shock, which may be accompanied by lacrimation, salivation, facial convulsions and other accompanying movements, often pressing the palm of the hand against the face or rubbing it hard, which may cause roughness and thickening of the skin on the affected side of the face and loss of eyebrows and sparse hair for a long time.
The pain site is limited to the distribution area of the trigeminal nerve, mostly unilateral, mostly on the right side, most commonly in the distribution area of the Ⅱ and Ⅲ branches, followed by the simple Ⅱ or Ⅲ branches, and the simultaneous involvement of the three branches is rare, and the involvement of the simple Ⅰ branch is also rare.
The pain duration lasts for several seconds or 1-2 minutes per attack and then stops abruptly, mainly during the day and decreasing at night.
④The frequency of attacks is intermittent and can be relieved by itself, and the natural interval can be several months to several years; with the prolongation of the disease, the frequency of attacks increases, the pain level increases, and the natural interval is shortened, even the whole day.
More than half of the pain trigger points may have “trigger points” or “trigger points”, which are often located at the upper lip, nose, corners of the mouth, incisors, palate, buccal mucosa, etc.; mechanical stimulation of the face, such as talking, eating, washing the face, brushing teeth or wind blowing, may cause attacks.
(2) Secondary trigeminal neuralgia is initially a clinical symptom of primary trigeminal neuralgia, and gradually appears as brain nerve, cerebellum and brainstem dysfunction, which can be life-threatening in severe cases due to increased intracranial pressure.
(3) Neurological examination Primary trigeminal neuralgia often has no positive signs in neurological examination; secondary trigeminal neuralgia should be considered if sensory disorders (especially dull or absent corneal reflex) or cerebral nerve dysfunction such as masticatory muscle weakness and atrophy, facial palsy, hearing loss, ataxia and other neurological abnormalities are found in the distribution area of trigeminal nerve.
(4) Ancillary examinations CT and MRI can help clarify the nature of intracranial occupying lesions causing secondary trigeminal neuralgia; special sequences of MRI can help clarify the etiology of microvascular compression in trigeminal neuralgia.
(iv) Differential diagnosis
(1) Other neuralgia ①Glottopharyngeal neuralgia ②Intermediate neuralgia
(2) Cluster headache
(3) Secondary trigeminal neuralgia caused by tumors of the bridge cerebellar horn, etc.; CT and MRI and other examinations can clarify
(v) Treatment
(1) Drug treatment is preferred to carbamazepine, but long-term use of this drug has side effects such as drowsiness, vertigo and digestive disorders, and may cause side effects such as abnormal liver function and reduced white blood cells.
(2) Surgery for primary trigeminal neuralgia where drug therapy is ineffective or the adverse effects of drugs are not tolerated (the majority of patients will be resistant to drugs after drug therapy, so more and more centers are now advocating early surgery). The main surgical methods include trigeminal nerve hemimelia closure, posterior hemimelia root thermal frequency surgery, trigeminal nerve sensory root dissection, trigeminal nerve microvascular decompression and stereotactic radiosurgery, etc. However, the most effective treatment is currently recognized as trigeminal nerve microvascular decompression, while other treatments have a low cure rate on the one hand and often cause numbness and other unbearable side effects on the other. For secondary trigeminal neuralgia, surgical removal of the lesion is required to cure the disease.