The diagnostic process for trigeminal neuralgia (TN) includes performing a physical examination, reviewing medical history, and conducting specific diagnostic tests. The goal is to confirm the involvement of the trigeminal nerve and its branches, as well as detect the possible causes of TN. Many other conditions can have symptoms similar to TN, so it is important to get an accurate diagnosis.
Physical Examination and Review of Medical History
The diagnostic process for TN begins with a physical examination and reviewing current symptoms with a doctor. This step includes:
- Checking for signs of redness in the face or eye of the affected side
- Examining parts of the face and jaw affected during the pain attacks—this also allows the doctor to understand the branches of the trigeminal nerve that may be affected
- Reviewing the type of pain, frequency of pain, and duration of pain attacks
- Asking about activities or movements that trigger the pain
Reviewing the medical history can also help a doctor to identify other possible conditions or factors that may be causing pain. Information on current medications, previous diagnosis, and/or past treatments are also useful in diagnosing TN.
Neurological Tests for Trigeminal Neuralgia
Trigeminal reflex testing is a neurological test that is performed in a doctor’s office to examine the facial sensitivity using certain materials and analyze the sensory responses. These commonly include cotton wool for touch, wooden cocktail sticks for pinprick, and thermo-rollers for cold and warmth. The doctor typically checks for two reflexes after using these materials—the blink reflex and masseter muscle inhibitory reflex. This allows the doctor to understand if the ophthalmic, maxillary, and/or mandibular branches of the trigeminal nerve are affected. The responses are recorded through surface electrodes with an electromyography (EMG) apparatus.
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Advanced Diagnostic Tests for Trigeminal Neuralgia
Advanced diagnostic tests for TN mainly include medical imaging tests, such as:
- Magnetic resonance angiography (MRA). MRA is a sensitive and specific method to diagnose TN caused by blood vessel compression. In this technique, a dye is injected into the blood vessel to highlight the blood flow. The presence and severity of compressions caused by blood vessels on nerves are well defined in MRAs.1
- Magnetic resonance imaging (MRI). An MRI shows a clear picture of soft tissues, such as the brain, spinal cord, and nerves. It can help assess nerve structure and is especially useful in determining whether TN is caused as a result of multiple sclerosis or tumors.
In some cases, such as idiopathic TN, even advanced diagnostic methods may not be helpful in determining the cause of TN.
Differential Diagnosis of Trigeminal Neuralgia
A variety of other conditions can mimic the symptoms of TN. A few examples are nerve pains such as glossopharyngeal neuralgia, post herpetic neuralgia, or occipital neuralgia. Inflammatory conditions such as dental pain, middle ear infections, giant cell arteritis, and sinus infections can also produce similar symptoms as TN. Severe forms of migraine and cluster headaches may also cause TN type pain in some people.
Getting an accurate diagnosis for trigeminal neuralgia can help ensure that the correct treatment plan is developed for pain relief.