Pennsylvania Neurological Associates, LTD

Charles S. Yanofsky, MD

Jon L. Vickery, MD

Albert W. Heck, MD

Francis J. Janton, III, MD

Liana Laza, MD

Harrisview Professional Center

108 Lowther Street, Lemoyne, PA 17043

717-774-2202

www.pneuro.com

By Charles S. Yanofsky, MD

Many newly diagnosed patients ask me whether multiple sclerosis is a painful disease. The answer, in general, is a qualified no. This is the textbook response. MS is not primarily a painful disease. We are most concerned about dysfunction. Yet patients frequently complain of significant pain. MS pain is archetypical for a kind of pain that resides purely in the central nervous system. Pain in MS does not come from tissue damage such as when you burn yourself or break a bone. This is worth emphasizing. No damage means no reason to panic the way you might if you were bleeding or being burned. You experience pain from some quirk or trick within your nervous system that creates pain, yet nothing life or limb threatening is happening. (This is not to say that you are immune to real injury and abnormal movements may expose you to arthritic or other problems but we won’t consider that here.)

The quintessential MS pain is trigeminal neuralgia (TN) or “tic doloreux”. In TN some irritant is pressing on or irritating the trigeminal nerve which gives sensation to the face, causing painful nerve fibers to electrically discharge. According to one hypothesis the fast touch myelinated nerve fibers are damaged. Fast fibers in an intact person inhibit the slow less myelinated pain fibers according to the Gateway theory of pain. When the fast touch fibers are inhibited, sensation becomes painful, so a slight touch, a gust of air, chewing, brushing, ordinary stimuli are intensely painful. An alternate explanation is that something touching a nerve merely increases sensitivity or irritability of the nerve. TN classically causes trains of intense terrible lancinations. It’s much worse than a bad toothache something that also affects a branch of the trigeminal nerve. By the way we now know that migraine headache pain very much involves this same trigeminal nerve complex.

TN is a disease of the old. A dilated vessel presses on the nerve irritating or “tickling” the nerve making it hypersensitive. But in MS younger folks get the same kind of facial pain. When a person younger than about 45 complains of typical TN type pain, MS is a primary diagnostic consideration particularly when it occurs on both sides, a rarity for non-MS TN. The lesion is sometimes in the pons. In the root entry zone where the Trigeminal nerve enters the brain is an MS plaque. Often this pain occurs as part of an MS attack, but a lot of the time it stays active for years. The first line therapies are anti-convulsant drugs that decrease spread of electrical discharges such as Carbamazepine or its oxy derivative, oxycarbazepine, gabapentin and others also baclofen, misoprostol, but many drugs are tried. Gamma knife and other ablative surgeries are a last resort.

Under ordinary circumstances pain signals damage and imminent danger to a painful body part. That naturally causes panic and avoidance which protects you. This ‘second tier’ reaction, panic-ridden pain response, can be treated as well by thoughtful discussion and as necessary other medicines especially SSRI’s, and anxiolytics. In MS pain is not a sign of imminent danger. It’s another trick or alteration of sensation coming from your nervous system.

If you understand TN you know a lot. Pain is encoded in electrical discharges as is all sensation and experience. MS demyelination slows electrical conduction, but it also makes axons function like frayed wires. They aberrantly conduct currents. Sometimes axons send currents directly to a neighbor when denuded of myelin, so-called ephaptic or touching transmission. LHermitte’s phenomenon that electrical shock variously over the body that happens when you flex your neck comes from ephaptic transmission. Neurons in the central or peripheral nervous system are made to discharge when they’re not supposed to and as a result you may have a host of sensory perversions. Dysesthesias, painful or burning sensations, parethesias, pins and needles, even allodynia when normal touch induces pain, result. Persons with MS have described too many sensory alterations over the years to mention, but, and chest or abdominal constrictions and rubber bands are among the most common. Transitory painful lightening jabs and sudden painful tonic spasms are also very common. Anatomic lesions in the spinal cord are the worst offenders, but some may happen in the root entry zone of a spinal (intercostal) nerve just like they do in TN or at very high brain levels affecting a side of the body as around the thalamus, the final common terminus for sensory conductions: thalamic pain. The most important part of our armamentarium is anti-convulsant medicine, followed by second tier drugs blunting sometimes exuberant emotional reactions to pain. Nowadays we have many newer medicines that affect chemical transmission of pain impulses at the pain synapse, so my advice is for you and your doctor to keep an open mind and to try to find some solution together. Physical therapies to maintain motion and function and provide alternative strategies are also helpful. Many kinds of pain worsen if a person stops moving, even though they are disinclined to move a painful body part. Most importantly the pain of MS poses no imminent danger and is another devilish trick of the central nervous system.

Brand Name	Generic	Usual DailyDose	Use	Comment
Tegretol, Carbatrol	carbamazepine	200-1200 mg	TN, dysesthesias, paresthesias, LHermitte, painful tonic spasm	Need for bloodwork, also clumsiness
Trileptal	oxycarbazepine	300-1200 mg	Same, less tested	Expensive but less side effects
Neurontin	gabapentin	300-4200 mg	Same	Treats all kinds of pain, safe and well tolerated
Various other anticonvulsants
Topamax	topiramate	100-400 mg	Affects neurotransmitters	Kidney stones sedation, and other side effects
Buspar	buspirone	20-60 mg	Second tier pain effects	Takes long to act
Paxil,Zoloft	Paroxetine, sertraline	10-40 mg, 25-200 mg	Second tier effect, anxiety and depression
Elavil, Pamelor, Desyrel others	Amitriptylene, nortriptylene, trazodone	25-150 mg 25-75 mg 50-400 mg	Anti-depressant, sleep aid, direct and secondary effects on pain	Dry mouth, constipation, hangover. Given at night
Valium, Ativan, Klonopin	Diazepam, lorazepam clonazepam	2-10 mg 0.5-3 mg 0.5-2.0 mg	Anti-spastic effects, sedative, for spasticity and secondary effects	Sedating
Zanaflex, Baclofen	Tizanidine Baclofen	4-36 mg 20-120 mg	Spasticity related pain, may have independent effects	Sedation, constipation, hypotension
Ultram	Tramadol	50-100 q 4-6 h.	Affects µ receptors	Many possible adverse effects
Cytotec, Arthrotec	Misoprostol, misoprostol with diclofenac	100-200mcg/D	May be worth trying in TN	Diarrhea, abs contraindicated in pregnancy or risk of pregnancy
NSAID’s			May be useful for various	GI ulceration, Renal impairment

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