An increased risk of this condition in patients with migraine headaches has recently been recognized.
A 57-year-old woman complains of three weeks of severe, constant, and throbbing pain on the left side of her head. She has a history of migraine headaches for about 15 years when she was her late thirties and throughout her forties. She has not experienced any headaches in the past several years.
In the past, she was prescribed sumatriptan to treat migraine symptoms, but she has not needed treatment for years. After a few weeks of her new headache pain, her primary care physician prescribed a total of five pills, which she took over the course of four days without any improvement.
The patient is approximately 40 pounds overweight, and she is postmenopausal. Otherwise, she is in good health, has had routine medical checkups and recommended screening tests (including mammograms), without any detected problems.
The patient appears healthy, alert, and oriented, as well cognitively intact. Heart rate and respiration are normal. Her skin, extremities, and pulses are normal; and her abdominal examination is normal. However, she appears to be in pain, often cupping her hand around her left cheek.
On her neurological examination, her strength, sensation, reflexes, and coordination are intact. and toes are downgoing. Her cranial nerve examination is normal, but her face is extremely sensitive to touch on the left side, which is the same side as her pain. There are no visible lesions on her face or eye, and she does not have any facial muscle weakness.
Brain MRI showed a small white matter hypo-density on the left internal capsule, which was reported as a chronic, incidental lesion. Brain MRA was completely normal. A lumbar puncture was normal.
Diagnosis: Trigeminal Neuralgia
This patient was diagnosed with possible trigeminal neuralgia that was treated with carbamazepine at a dose of 200 mg twice per day. She experienced gradual improvement of symptoms, but she was extremely sleepy to the point that driving was unsafe. Two weeks after initiating treatment, the pain subsided. After her month’s supply of carbamazepine was finished, she did not refill her medication.
Six months later, the pain returned. She again improved within two weeks with the same 200 mg BID dose of carbamazepine, but she was unable to tolerate the sleepiness. She had recurrent pain when she discontinued the medication. Baclofen treatment produced a similar reaction, followed by lamotrigine, which also improved symptom but also induced excessive sleepiness. A trigeminal ganglion nerve block stopped recurrence of symptoms or adverse effects. At her most recent follow up two years after the nerve block, she had not had any more symptoms.
Trigeminal neuralgia is a focal peripheral neuropathy involving the fifth cranial nerve (the trigeminal nerve). It is characterized by severe intermittent unilateral facial pain, typically of a throbbing nature. It is also called tic douloureux (painful tic) because patients often contort the face as a result of the pain.
This patient’s presentation is atypical in two ways: she complained of continuous pain rather than intermittent pain, and the pain involved her head, not her face. Atypical trigeminal neuralgia is described as continuous, rather than intermittent facial pain.
The head pain rather than facial pain could have been because of a variety of factors. She may have had an unusual pain pattern due to an unusual variant of trigeminal neuralgia, or the pain could be the result of head and scalp hypersensitivity resulting from years of migraine headaches. Pain due to trigeminal neuralgia may have been similar to that of migraines, as her past migraine headaches may have involved her face.
It is common for migraine headaches to cause facial pain, sometimes without head pain at all. It is also possible that the description of her symptoms could have been the result of the patient's own bias after having had migraine headaches for so many years.
Strictly unilateral symptoms can be concerning, as they are not characteristic of migraine headaches and could suggest a non-benign etiology. In this case, facial hypersensitivity upon physical examination was a diagnostic clue that suggested trigeminal neuralgia. Her improvement with carbamazepine rather than sumatriptan, while possible with migraine headaches, was another clue that suggested trigeminal neuralgia.
Trigeminal neuralgia is condition that affects males and females of all ages and is more common after the age of 60. It is usually idiopathic and may be caused by irritation of the trigeminal nerve due to inflammation or compression. Compression is usually caused by a blood vessel but can result from a tumor or other mass. It has also been associated with multiple sclerosis and inflammatory or autoimmune conditions. A trigger, such as an injury to the facial region, may precede the onset of symptoms. An increased risk of trigeminal neuralgia in migraine patients has recently been recognized.1
The condition is not dangerous, but the persistent pain can be limiting in terms of daily activities. Most patients respond well to the anticonvulsants carbamazepine or oxcarbazepine.2 Second-line agents include lamotrigine, an anticonvulsant, as well as baclofen, a muscle relaxant. Often, other anticonvulsants, such as topiramate and gabapentin are considered.
If an anatomical etiology is identified, decompression of a blood vessel or other anatomical source of compression may relieve the pain. For patients who are resistant to pharmacologic treatment, if no anatomical etiology is identified, a trigeminal ganglion nerve block or injections with botulinum toxin may be considered. Rhizotomy or gamma knife surgery to sever the nerve root may prevent pain in the trigeminal nerve distribution, and usually results in impairment of facial sensation.
Take Home Points
• It is important to consider other causes of pain besides migraine headaches in patients who have a history of migraine headaches
• Atypical trigeminal neuralgia presents with continuous pain, rather than the intermittent pain that is more typical of the condition
• Trigeminal neuralgia can recur, particularly if the medication is stopped abruptly
1. Lin KH, Chen YT, Fuh JL, Wang SJ. Increased risk of trigeminal neuralgia in patients with migraine: A nationwide population-based study. Cephalalgia. 2016;36:1218-1227.
2. Di Stefano G, Truini A, Cruccu G. Current and Innovative Pharmacological Options to Treat Typical and Atypical Trigeminal Neuralgia. Drugs. 2018;78:1433-1442.