How do you examine a patient for trigeminal neuralgia?

Examining Trigeminal Neuralgia

The examination of trigeminal neuralgia is primarily based on clinical history, as physical examination is typically normal in classical trigeminal neuralgia, while MRI is the recommended imaging modality to evaluate the full course of the trigeminal nerve and identify potential causes. 1, 2

Clinical History Assessment

• Focus on identifying the characteristic sudden, unilateral, severe, brief, stabbing, and recurrent episodes of pain following the distribution of one or more branches of the trigeminal nerve 3, 4
• Document pain triggers such as light touch, washing, cold wind, eating, brushing teeth, talking, or shaving 1, 5
• Determine if pain attacks occur spontaneously or are triggered by non-noxious stimuli 5
• Assess for paroxysmal pain pattern (seconds to minutes) with refractory periods between attacks 1, 6
• Note the distribution of pain according to trigeminal nerve branches (V1-ophthalmic, V2-maxillary, V3-mandibular) 3
• Inquire about any persistent background pain, which may predict worse treatment outcomes 5

Physical Examination

• Perform a complete neurological examination, which is typically normal in classical trigeminal neuralgia 2
• Assess for sensory deficits (facial numbness) or motor deficits (weakness with mastication), which may suggest trigeminal neuropathy rather than classical neuralgia 3
• Test for trigger points by lightly touching areas of the face that provoke pain attacks 4
• Evaluate for signs of secondary causes such as multiple sclerosis or cerebellopontine tumors 2
• Rule out trigeminal autonomic cephalalgias by checking for absence of autonomic features like tearing, eye redness, and swelling 1

Differential Diagnosis

• Distinguish from toothache or trigeminal autonomic cephalalgias 4
• Rule out SUNCT/SUNA syndromes which present with both pain and autonomic features like conjunctival injection and tearing 1
• Consider temporal arteritis in patients over 50, which presents with continuous dull aching pain rather than paroxysmal attacks 6
• Evaluate for orbital inflammatory conditions when eye pain and swelling occur together 1

Imaging Studies

• MRI is the recommended imaging modality to evaluate the full course of the trigeminal nerve 3
• MRI should assess for neurovascular compression at the trigeminal root entry zone, which has high correlation with classical trigeminal neuralgia 5
• Imaging should cover the entire course of the nerve from brainstem to peripheral branches 3
• Look specifically for demyelinating lesions in the brainstem that could indicate multiple sclerosis 3
• Evaluate for other potential causes such as tumors, vascular lesions, and inflammatory processes affecting the trigeminal nerve 3

Important Clinical Pearls

• The diagnosis is made almost entirely based on the patient's history, as there are currently no objective tests to confirm trigeminal neuralgia 2, 7
• Classical trigeminal neuralgia does not typically cause visible inflammation or swelling 1
• Pain in the ophthalmic branch (V1) typically lasts seconds to minutes with a refractory period between attacks 1
• Fear and depression may develop in patients with severe trigeminal neuralgia 6
• Early neurosurgical consultation should be considered if medical management fails 4

By systematically evaluating the clinical history, performing a targeted physical examination, and obtaining appropriate imaging studies, clinicians can accurately diagnose trigeminal neuralgia and differentiate it from other facial pain syndromes, leading to appropriate treatment decisions.