Other than Neurontin, what can I take for nerve pain? Would Estrogen therapy help?
Question Date: 8/28/2012
Answer: Although multiple sclerosis was previously thought of as a “painless” disease, it is now recognized that pain is a common symptom in MS, affecting over 50% of patients at some point in their disease. Unfortunately, pain is a rather generic term that can refer to numerous underlying issues; in addition, people have different “tolerances,” above which stimuli are deemed as painful. Certainly, the factors for the later are an area of intense research. Pain may refer to a local destructive process (i.e. skin breakdown from sacral decubitus ulcer, fracture, or trauma) or may represent a disruption in the mechanism for sensory input, including altered sensory signals (dysthesias) or the sensation that normal stimuli are painful (allodynia). An individual’s experience of pain is likely altered by co-existing conditions and previous experiences with pain (or health care response to pain). Obviously, not all painful sensations in an MS patient are a direct result of multiple sclerosis; therefore, the first step in pain management is to appropriately delineate the nature / etiology of the specific pain (or pains) in question. As with most MS symptoms, treatment of pain in MS is accomplished best by utilizing a team approach including pharmacological and non-pharmacological modalities.
Many people suffer from musculoskeletal pain, often due to abnormal “wear and tear” of muscles or joints. Often, this is described as an aching pain, usually precipitated (or exacerbated) by certain movements, and often responsive to non-steroidal anti-inflammatory medications (like ibuprofen), heat, ice, and rest. Physical therapy is often helpful with this type of pain, providing exercises to strengthen muscle and increase flexibility, to normalize function and improve posture. Therapists also use other modalities, including ultrasound or electric stimulation, to relieve pain. Musculoskeletal pain is quite common in patient with multiple sclerosis and may be due to alterations in function due to acquired neurological deficits. For example, one patient with a foot drop due to leg weakness may develop hip or back pain from “hiking the hip upwards” to clear the foot when walking; others may get pain in the good leg because of “overuse” in an attempt to compensate for the affected limb. Patients with LE weakness from spastic paraparesis may hyperextend their knee (genu recurvatum), which can lead to abnormal wear and tear (and pain in the affected joint); on the other hand, if the weakness is severe, a joint may develop a decreased range of motion or even freeze (develop a contracture) due to decreased movement.
Spasticity is a very common finding in patients with multiple sclerosis. Although often described as “muscle stiffness,” it is defined as “velocity-dependant resistance to muscle stretch”. Although spasticity is sometimes painful (causing muscle stiffness and spasms), it can often be beneficial, allowing patients to compensate for underlying weakness, in that a spastic leg is often stiffly extended, and a spastic arm is often in flexion. Obviously, too much tone can not only be painful, but it can also interfere with function and increase fatigue (due to the excessive muscle contraction). Unfortunately, other types of pain (or infection) can exacerbate spasticity, at times leading to a “vicious cycle” of increased pain and increased spasticity. Treatment of spasticity is also multi-disciplinary, often involving physical therapy (active and passive stretch) and medications like baclofen (Lioresil) and tizanidine (Zanaflex).
• It is thought that this nerve pain is caused by an aberrant signal jumping from one damaged nerve to another (so-called ephaptic transmission), which is likely why this type of pain often responds to seizure medications (anti-convulsants), which probably reduce the aforementioned “short circuits.” Gabapentin (Neurontin) or pregabalin (Lyrica) is often used to treat this type of pain; other epilepsy medications like lamotrigine (Lamictal) or carbamazepine (Tegretol) can also be used. Tricyclic antidepressants like amitriptyline (Elavil) and nortriptyline (Pamelor) can also be effective.
Depression is very common in patients with MS (much more so than in the general population), and often “depression hurts,” especially in patients who have significant other issues with pain. I suspect that there is a vicious cycle with pain and depression with worsening pain leading to worsening depression, and vice versa, and I have had patients experience improvement with both mood and pain with agents like duloxetine (Cymbalta) and venlafaxine (Effexor).
The topic of hormones in MS deserves an article by itself. Given that women are over 3 times more likely to get MS than men suggests that female hormones play a role in MS; it has also been observed that pregnancy is a relatively protective time from an MS point of view, but the disease is often quite active in the post-partum period. These observations have lead to some ongoing clinical trials in MS. Certainly, the Women’s Health Initiative raised significant questions about the safety of hormone replacement, and there is very little data to support hormones for pain relief.
Answer Date: 8/28/2012