Trigeminal Neuralgia Definition
Trigeminal neuralgia is a chronic neuropathic pain disorder characterized by sudden, unilateral, severe, brief stabbing recurrent episodes of electric shock-like pain in the distribution of one or more branches of the trigeminal nerve. 1, 2
Core Clinical Features
The defining characteristics that distinguish this condition include:
- Pain quality: Electric shock-like, lancinating, stabbing sensations that are abrupt in onset and termination 3, 4
- Duration: Individual pain attacks last only seconds to minutes, with a characteristic refractory period between attacks 5, 4
- Distribution: Pain follows the anatomical distribution of one or more trigeminal nerve branches (V1, V2, or V3), most commonly affecting V2 and V3 1, 3
- Trigger zones: Small, specific areas where minimal stimulation precipitates painful flare-ups 3, 6
- Provocative factors: Seemingly benign stimuli such as light touch, washing the face, cold wind, eating, brushing teeth, talking, or chewing can trigger attacks 7, 8, 3
Pathophysiology
The underlying mechanism involves nerve root contact, compression, and subsequent demyelination, most commonly from neurovascular compression at the trigeminal root entry zone 3, 4. This focal mechanical compression near the brainstem is implicated as the central pathophysiology in classical trigeminal neuralgia 3.
Classification Types
Three distinct categories exist based on etiology:
- Classical trigeminal neuralgia: Caused by direct neurovascular compromise due to anatomic compression 3
- Secondary trigeminal neuralgia: Results from another identifiable condition such as multiple sclerosis, tumors, or other structural lesions 3, 4
- Idiopathic trigeminal neuralgia: No identifiable etiology can be determined 3
Key Distinguishing Features
Trigeminal neuralgia does not typically cause visible inflammation, swelling, or autonomic features in its classical form 5. The neurological examination is characteristically normal between painful episodes 3, 4. This absence of autonomic symptoms (such as tearing, eye redness, rhinorrhea) is critical for differentiating it from trigeminal autonomic cephalgias like SUNCT/SUNA 1, 5.
Epidemiology and Impact
The average age of onset is 50 to 60 years, with incidence increasing with age 3. The condition has a profound effect on quality of life, with pain so intense that many patients develop fear and depression if severe 8, 2.