Trigeminal Neuralgia Causes and Diagnostic Approaches

Primary Mechanism: Neurovascular Compression

• The American College of Radiology suggests that the central pathophysiology of trigeminal neuralgia involves direct compression of the centrally myelinated portion of the trigeminal nerve root, usually at the root entry zone near the brainstem, causing focal demyelination and ectopic impulse generation 1, 2

Secondary Causes of Trigeminal Neuralgia

• Multiple sclerosis can produce trigeminal neuralgia through brainstem demyelinating plaques affecting the trigeminal nerve nuclei or pathways, necessitating brainstem imaging to identify demyelinating lesions 1, 2
• The American College of Radiology recommends considering structural lesions along the nerve course, including tumors, vascular lesions, inflammatory/infectious processes, and brainstem lesions, as potential causes of trigeminal neuralgia 1, 2

Critical Diagnostic Distinction

• The American College of Radiology emphasizes the importance of distinguishing classical trigeminal neuralgia from trigeminal neuropathy, as they have different etiologies and management approaches, with classical trigeminal neuralgia characterized by neurovascular compression without sensory or motor deficits between attacks 1, 2

Imaging to Identify Cause

• The American College of Radiology recommends MRI with high-resolution sequences covering the entire trigeminal nerve course to identify the specific cause and guide treatment, with pre- and post-contrast MRI providing optimal lesion detection, and 3D heavily T2-weighted sequences and MRA characterizing neurovascular compression 1, 2, 3