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Who Is At Risk For Trigeminal Neuralgia & Is There A Blood Test For It?

Who Is At Risk For Trigeminal Neuralgia?

The exact cause of trigeminal neuralgia (TN) is not known, it is believed that damage or pressure to the trigeminal nerve may be the cause of the disease. The “ignition theory” is the main hypothesis which states that TN is due to abnormalities in the afferent nerves of the trigeminal root or ganglion. Damage to the axons can make the neurons hyperexcitable and cause pain leading to painful neuropathy.

The vascular compression is another theory. Peripheral and central mechanisms can cause damage and pressure and alter the trigeminal nerve microstructure however, there is no apparent disease seen in the trigeminal nerve. The damage or pressure can be from a blood vessel near the trigeminal nerve root near its entry to the pons which can press, damage or irritate the nerve or it can be due to a genetic disorder in the blood vessels. The vascular compression theory can be supported by the surgical decompression and MRI findings however, not all trigeminal neuralgia patients have evident vascular compression.

Since the exact cause is not known the risk factors are not known exactly but according to studies done on patient’s diagnosed with trigeminal neuralgia, the following can be risk factors:

Age: trigeminal neuralgia is seen most of the time in people older than 50 years (the range is between 37-67 years). It’s rare in people less than 50 years unless they have another risk factor such as multiple sclerosis or a tumor

Gender: Women are more prone to get trigeminal neuralgia than men, the ratio is about 3:1.

Tumor In The Nervous System: Tumor close to a root of the trigeminal nerve can press, irritate or damage the nerve giving rise to the trigeminal neuralgia symptoms.

Multiple Sclerosis: The relative risk of getting trigeminal neuralgia in patients with multiple sclerosis is 20%. Damage to the myelin sheath of the trigeminal nerve can cause sclerosis in the nerve leading to trigeminal neuralgia.

Hypertension: Hypertension is a risk factor for women and men. The relative risk is about 2.1% for women and 1.53% for men. Hypertension is considered a risk factor for women more than men.

Charcot-Marie-Tooth Disease: It’s an inherited motor and sensory neuropathy. ^{(1) (2) (3)}

Is There A Blood Test For It?

Diagnosis of trigeminal neuralgia is based on history and examination mainly, it’s a clinical diagnosis. There aren’t any specific tests to confirm the diagnosis. There isn’t any blood test to diagnose trigeminal neuralgia. However, magnetic resonance imaging (MRI) can be done to identify secondary causes such as multiple sclerosis or tumors that irritate the trigeminal nerve. Routine neuroimaging detects a cause in 15% of the patients. MRI rarely detects the precise cause of trigeminal neuralgia as vessels next to the nerve is difficult to see even in a high-resolution MRI but sometimes vascular compression can be seen by a high-resolution MRI. Investigations can be done to exclude other causes of facial pain. Sensory testing, evoked potentials, and electrophysiological studies can also help identify TN but it’s not recommended as routine tests for patients.

Conclusion

The exact cause of trigeminal neuralgia is not known, it can be due to abnormalities in the afferent nerves of trigeminal root or ganglion or it can be due to vascular compression from blood vessels. Therefore, the exact risk factors are not known but according to studies done on patients diagnosed with trigeminal neuralgia the following can be risk factors: older age, female gender, tumors in the nervous system, multiple sclerosis, stroke, hypertension, and Charcot- Marie-Tooth disease. There aren’t any blood tests to confirm trigeminal neuralgia, it’s mainly a clinical diagnosis. Neuroimaging especially MRI may visualize vascular compression in some patients but in most cases, the MRI would be normal. Sensory testing, evoked potentials, neuroimaging, and electrophysiological studies can be done to exclude other causes of facial pain. ^{(4) (5)}

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Who Is At Risk For Trigeminal Neuralgia & Is There A Blood Test For It?