Trigeminal neuralgia — also known as tic douloureux — is a chronic neuropathic pain disorder characterized by severe, unilateral, paroxysmal facial pain resulting from mild stimulation in the craniofacial sensory distribution of the trigeminal nerve. The onset of symptoms is usually spontaneous or sudden and may be triggered by chewing, talking, or teeth brushing.1,2 The symptoms of trigeminal neuralgia are often described by patients as stabbing, burning, or electric shock-like pain felt in the lower face or jaw that is often incapacitating and limits the ability to perform activities of daily living.1-3
The chronic, debilitating, and unpredictable pain of trigeminal neuralgia has been described as one of the most severe pain types and is associated with an increased incidence of depression and anxiety disorders as well as poor quality of life.1 Trigeminal neuralgia is a relatively rare condition, affecting 4 to 13 per 100,000 people per year.2,3 This pain condition primarily affects adults aged 50 years and older, and is more common in women than in men.3
Trigeminal neuralgia can be classified into 1 of 3 classes based on the underlying cause: idiopathic, classic, or secondary.3 Idiopathic trigeminal neuralgia has no known cause. Classic trigeminal neuralgia is associated with neurovascular compression in the root entry zone of the trigeminal nerve, leading to demyelination and upregulation of voltage-gated sodium channels.3 Secondary trigeminal neuralgia is most closely associated with arteriovenous malformations, posterior fossa space-occupying lesions, tumors, or multiple sclerosis.
Clinical Features of Trigeminal Neuralgia
The trigeminal nerve is the fifth cranial nerve and has 3 branches (Figure): the ophthalmic (V1), maxillary (V2), and mandibular (V3) nerves. The branches most commonly associated with trigeminal neuralgia are V2 (which innervates the upper lip, maxillary teeth, and mucosa) and V3 (which innervates the mandibula, lower lip, mucosa, and mandibular teeth).3
Classically, the patient will present with 10/10 facial pain triggered by teeth brushing, shaving, talking, or chewing within the distribution of the V2 or V3 branches. Trigeminal neuralgia is notable for being unilateral, stabbing, paroxysmal, and lasting anywhere from a few seconds to several minutes per episode.3 The pain can be relapsing and remitting and occurs with increasing frequency over time, making early diagnosis and treatment essential to care.
The chronicity of pain can lead to the subsequent development of psychiatric illnesses, with depression and anxiety being the most common comorbidities of trigeminal neuralgia.4 Early identification and concurrent treatment of depression are essential to optimal management of trigeminal neuralgia as depression can exacerbate pain symptoms, further decreasing activities of daily living and affecting the success of therapeutic outcomes.3,5 Additionally, depression can lead to social isolation and withdrawal from personal relationships.
Differential Diagnosis of Facial Pain
Headaches and facial pain are extremely common complaints in the clinical setting, and it is important to discern the underlying cause of these pain symptoms to ensure the timely initiation of effective treatment. A detailed medical history and physical examination often elucidate an accurate diagnosis.
When facial pain is the presenting symptom, trigeminal neuralgia should remain high on the list of differential diagnoses despite it being a relatively rare condition. Trigeminal neuralgia is most commonly misdiagnosed as an acute migraine. Temporomandibular disorders, cluster headache, and postherpetic neuralgia also should be included in the differential diagnosis. These diagnoses can be distinguished from trigeminal neuralgia by analyzing the nature, intensity, and duration of pain.6 Clinicians should consider the chronicity, unilateral or bilateral location, and sharp or dull characteristics of the pain. Trigeminal neuralgia is best identified by the presence of stabbing or electric shock-like pain produced in response to innocuous stimuli in affected patients.