Trigeminal Neuralgia-The Intense Pain
BY Dr Smrutirekha Hota
What is trigeminal neuralgia?
Trigeminal neuralgia is a painful condition, mainly involves one side or rarely both sides of the face. It affects the trigeminal nerve and its branches which carry sensation from the face to brain. Patients usually complain of lancinating or sharpshooting type of short-lived and severe pain on touching the face, chewing, or even talking. Trigeminal neuralgia affects women more than men, and it’s more likely to occur in elder people of age more than 50 years. In addition, 5% of the population with positive family history is also involved.
How trigeminal neuralgia progresses?
The patient initially experiences short duration and mild attacks of pain in the upper face, nose, mouth, teeth. These painful attacks usually feel like an electric shock that lasts for a few seconds. But trigeminal neuralgia can progress to more frequent episodes starting from 4 to 5 times a day initially to even 40 to 50 times a day in later stages. For example, the patient experiences pain while chewing, brushing teeth initially; however, in advanced settings, even fan air can result in excruciating pain.
How to diagnose trigeminal neuralgia?
Diagnosis is usually made from the clinical description of pain like type, location, triggering factors. Sometimes a neurological examination is required to determine the exact site of pain and which nerve branch is involved and to look for reflexes. MRI scan of the brain is sometimes necessary to look for other causes like multiple sclerosis or brain tumor. MR angiogram for visualization of arteries and veins of the brain may be required in a few patients. As facial pain has many different causes, accurate diagnosis is essential.
Know more about Trigeminal Neuralgia in Bengali
Listen to the discussion on trigeminal neuralgia. It is moderated by Dr Gautam Das and panelists were Dr Chinmoy Roy and Dr Debjyoti Dutta.
The discussion was entirely in the Bengali language to make it easy to understand by laypeople.
For more questions contact Daradia directly.
How to differentiate trigeminal neuralgia from other disorders?
Other sources of facial pains are
- Dental pain -It is a kind of pain that is monotonous. It is not like a sharp shooting pain (electric shock) of Trigeminal Neuralgia. The pain is increased with chewing, hot or cold sensitivity, bleeding or discharge from around a tooth or gums, swelling around a tooth or swelling of your jaw, injury or trauma to the area, local examination of mouth cavity helps in identifying dental pain.
- TMJ pain – If the patient experience any symptoms that don’t pain like limited jaw movement or tinnitus, We have to rule out trigeminal neuralgia also. Instead of being a constant dull ache like TMJ, trigeminal neuralgia pain often strikes in more painful attacks. Patients experience limited but more intense pain. Pain is usually continuous and experienced during mouth opening.
- Glossopharyngeal neuralgia – Glossopharyngeal neuralgia causes pain in the tonsils, posterior pharynx, throat, and ear and may be initiated by coughing, yawning, or sometimes swallowing cold or cold liquids. But in trigeminal neuralgia, pain is along with the different distribution of the nerve.
- Non-specific facial pain/myofascial pain: Myofascial pain is categorized by extensive pain, decreased pain relief, sleep disruption, exhaustion, psychosomatic distress, and chronic headache. Patients with myofascial pain are identified based on the presence of numerous tender points.
Why does trigeminal neuralgia occur?
Primary or idiopathic trigeminal neuralgia may be caused due to contact between any aberrant blood vessels and the trigeminal nerve where the former puts pressure and rubs the nerve causing demyelination (as the skin gets peeled due to repeated scratching similarly, the covering of the nerve gets damaged by pulsating artery friction). Patient experiences pain due to the damaged nerve. This is a hypothesis which is not been proved yet.
Among other causes, aging, multiple sclerosis, demyelinating disorders, compressive tumors, stroke, facial trauma, surgical injuries may be responsible for trigeminal neuralgia.
What other investigations are done in trigeminal neuralgia patients?
- MRI is done to rule out the secondary causes of trigeminal neuralgia by MRI
- Blood test to rule out inflammatory conditions
How to start treatment?
Like any other chronic disease, we can not cure it entirely. Still, we can control the severity of the disease. In this condition, the strongest pain killers also do not work as the source of pain is the nerve; hence, the drugs are used for neuropathic pain control.
What is the treatment approach to trigeminal neuralgia patients?
- Local injection
Medication commonly used is carbamazepine
- Carbamazepine is an anti-epileptic drug, but it is effectively used for trigeminal neuralgia patients. It usually alleviates the pain effectively. However, it has to be started at a low dose. In addition, it causes side effects like sleepiness, gastrointestinal disturbances, head reeling, low sodium in the body leading to mental disorders commonly in elderly patients.
- Carbamazepine is started at low doses of 100 mg thrice daily, increasing gradually.
- Carbamazepine is to be continued for a more extended period without any time limit, and carbamazepine doses to be escalated gradually till the desired effect is achieved.
- Before starting carbamazepine, routine blood tests are done. In some patients, blood count may reduce after starting the drug. In addition, Steven Johnson syndrome is an uncommon but potentially severe condition with carbamazepine where a stoppage of the drug is warranted.
- In patients intolerant to carbamazepine, we can give oxcarbazepine due to fewer side effects.
- Baclofen is given in some cases.
- Pregabalin and Gabapentin can be tried in a few cases.
What if the drugs are not effective in trigeminal neuralgia?
Suppose the medical treatment is ineffective in controlling the pain severity or patients are intolerant to the drugs due to their side effects. In that case, pain intervention is to be performed.
Radio-frequency ablation of Gasserian ganglion is performed to block the pain pathway. It is a minimally invasive procedure where the needle enters the brain through the face, and heat energy is delivered. It is different from the common injection, but it doesn’t require any brain surgery.
How radiofrequency ablation of Gasserian ganglion is done?
- An OT setup is needed for this procedure, which is done under an X-ray machine.
- No general anesthesia is required, usually done under local anaesthesia.
- Under fluoroscopy guidance, the Gasserian ganglion is identified, cross-checked via an electrical stimulation test.
- After radiofrequency ablation of the ganglion, slight numbness in the mouth may remain, but it gradually disappears with time.
What are radiofrequency ablation’s short-term and long-term side effects?
Immediately after the procedure, needle prick site pain can be felt, which lasts for approximately 2 to 3 days.
Sometimes swelling of the face can last for 1-2 days as the face is highly vascular.
Numbness of the face for 7 to 10 days may be experienced by some patients after the procedure.
Complications – vocal cord paralysis can occur, but it is not permanent. It is seen in 1 in 500 patients due to the needle injury to the surrounding nerves of Gasserian ganglion.
Is there any life risk?
Before starting the procedure, coagulation parameters are to be checked to prevent bleeding complications, and prophylactic antibiotics are to be given to prevent infection, especially in diabetic patients with adequate blood sugar control.
It is not done when there are local infections, sepsis, coagulopathy, increased intracranial pressure, major psychopathology.
Under image guidance and nerve stimulation test, the complications rates are minimal if the needle is placed correctly with precaution.
Is there any other procedure besides radiofrequency ablation for trigeminal neuralgia?
- In the percutaneous balloon micro compression method, a big needle of 14G, 10 cm, then a caterer called a Fogarty catheter inserted, so the severity of pain and bleeding risk is more. We need general anaesthesia to perform it. But no extra advantages in terms of duration of pain-free period.
- Surgical microvascular decompression-Surgery involves making a hole in the skull (craniotomy) and exposing the nerve at the base of the brain to insert a tiny sponge between the compressing vessel and the nerve. Microvascular decompression recovery time may span between two and four weeks, with gradual progress made along the way. Microvascular decompression involves risks of, Infection. Hearing loss, facial numbness, and/or facial weakness (usually temporary, rarely permanent) Spinal fluid leak. Recurrence may occur in 18–30% of patients, mainly within 2 years of surgery.
- Percutaneous Glycerol rhyzolysis injection is an old technique, but the pain relief is very short-lasting. Here we put a needle filled with a small amount of glycerol into the ganglion from where the trigeminal nerve divide and comes out of the skull. This procedure blocks pain signals in the trigeminal nerve and helps to reduce pain.
- Cryoablation of superficial branches of trigeminal nerve and Gasserian ganglion is very effective for trigeminal neuralgia. In this method, a needle is passed similarly as of radiofrequency ablation, then the nerve is frozen at -800 C. Cryoablation has the advantage of less painful condition and without any motor paralysis.
- Stereotactic microvascular decompression is only done when the patient is unfit for either intervention or surgery. Gamma Knife treatment for trigeminal neuralgia stops pain in most patients, usually within 10 days.
How effective is stereotactic radiation therapy or Gamma knife?
The Gamma Knife is a device that delivers precise, controlled beams of radiation that target nerves inside the skull, including the brain and associated nerves. Pain relief in gamma knife is not immediate, and the failure rate is high. However, a needle prick is not needed for this procedure. Side effects are there, and that include tingling or numbness in the face
Take home message
- Best pain relief is obtained by RFA for an approximate period of 5- 10 years.
- Glycerol injection effectiveness is about 5 to 6 months; hence repeated injections are required.
- Young patients with trigeminal neuralgia are preferred surgery to elderly patients, but before surgery, radio-frequency ablation should be tried as the pain relief is more consistent with it.
- Surgery is not a permanent cure method as recurrences are common even after surgery, and surgery has more side effects.