From the Guidelines
Diagnosing trigeminal neuralgia primarily relies on a thorough clinical history and physical examination, with a focus on identifying brief episodes of severe, electric shock-like facial pain triggered by light touch in the distribution of the trigeminal nerve. The diagnosis is made when a patient reports these characteristic episodes, which typically last seconds to minutes, with pain-free intervals between episodes 1. During examination, the clinician should attempt to identify trigger zones by lightly touching areas of the face.
Key Diagnostic Features
- Neurological examination is typically normal in classic trigeminal neuralgia
- Brain MRI with contrast is essential to rule out structural causes like tumors, multiple sclerosis plaques, or vascular compression of the trigeminal nerve
- Trigeminal reflex testing may help differentiate between classic and symptomatic trigeminal neuralgia
- Laboratory tests are not diagnostic but may help exclude other conditions
Diagnostic Criteria
The International Headache Society criteria require at least three attacks of unilateral facial pain along the trigeminal distribution, with pain having characteristic qualities (intense, sharp, superficial, or stabbing) and being triggered by innocuous stimuli 1.
Differential Diagnosis
Differential diagnosis should consider:
- Dental pathology
- Cluster headache
- Glossopharyngeal neuralgia
- Other facial pain syndromes, such as post herpetic neuralgia, post traumatic trigeminal pain, atypical odontalgia, burning mouth syndrome, and short unilateral neuralgiform pain with autonomic features (SUNA)/SUNCT conjunctival injection and tearing 1 Early diagnosis is crucial as first-line medications like carbamazepine or oxcarbazepine can provide significant relief for many patients 1.
From the Research
Diagnosis of Trigeminal Neuralgia
To diagnose trigeminal neuralgia, the following steps can be taken:
- Identify the characteristic symptoms of trigeminal neuralgia, including touch-evoked unilateral brief shock-like paroxysmal pain in one or more divisions of the trigeminal nerve 2
- Use new diagnostic criteria that subclassify trigeminal neuralgia based on the presence of trigeminal neurovascular conflict or an underlying neurological disorder 3
- Perform MR imaging, including high-resolution trigeminal sequences, as part of the diagnostic work-up 3
- Consider the patient's medical history and perform a physical examination to rule out other possible causes of facial pain 4
Differential Diagnosis
Differential diagnoses for trigeminal neuralgia include:
- Trigeminal autonomic cephalalgias 2
- Posttraumatic or postherpetic pain 2
- Other facial pains 2
- Multiple sclerosis or a space-occupying lesion affecting the trigeminal nerve, which can cause secondary trigeminal neuralgia 2, 5
Diagnostic Tests
Diagnostic tests that can be used to support the diagnosis of trigeminal neuralgia include: