Multiple Sclerosis (MS) is a chronic condition impacting the central nervous system, which includes the brain, spinal cord, and optic nerves. This condition disrupts the flow of information within the brain and between the brain and body. While MS does not typically induce shoulder pain in the same manner it causes numbness or weakness, there are significant indirect ways and co-occurring conditions that link the two.
Direct Neurological Links to Shoulder Pain
While less common, MS lesions can neurologically influence shoulder sensations. Lesions, damage to the myelin sheath protecting nerve fibers, can occur in the brain or spinal cord. If located in regions processing shoulder sensory information or controlling movement, they can lead to pain, tingling, or other sensations. This neuropathic pain results from nerve damage.
Damage to sensory pathways transmitting shoulder signals to the brain can misinterpret them, causing pain. Lesions affecting motor pathways that control shoulder muscles can cause muscle imbalances or spasms, leading to discomfort. Though not a common presentation, this direct neurological link is possible due to widespread lesion formation in the central nervous system.
How MS Symptoms Indirectly Contribute to Shoulder Pain
MS symptoms can indirectly contribute to shoulder pain. Spasticity, involving muscle stiffness and involuntary spasms, affects shoulder muscles. This tension limits range of motion, causing chronic stiffness and discomfort. Sustained spasticity can pull the shoulder out of alignment, straining tendons and ligaments.
Weakness in arm and shoulder muscles, a common MS symptom, compromises joint stability. When muscles cannot properly support the joint, it becomes susceptible to strain and injury, leading to pain. This weakness can also cause poor posture, placing excessive stress on the shoulder and upper back. Balance and gait issues, common in MS, increase fall risk. Attempting to brace during a fall can injure the shoulder, causing acute or chronic pain.
Fatigue, a common MS symptom, can exacerbate shoulder pain by encouraging reduced physical activity and inactivity. This leads to muscle deconditioning, making muscles prone to pain and injury. The use of mobility aids like canes, crutches, or wheelchairs also places repetitive stress on shoulder joints. For instance, propelling a manual wheelchair involves repetitive arm and shoulder movements that can strain the rotator cuff and other shoulder structures over time.
Common Shoulder Conditions in People with MS
People with MS are susceptible to common shoulder conditions, though MS symptoms can heighten their risk or severity. Rotator cuff injuries, involving tears or inflammation of shoulder tendons, are prevalent. Muscle weakness and altered movement patterns associated with MS can increase the likelihood of these injuries. For example, a weakened deltoid muscle may not adequately support the shoulder, leading to impingement of the rotator cuff tendons.
Shoulder impingement syndrome occurs when rotator cuff tendons compress in a narrow shoulder space. This condition is often aggravated by repetitive overhead movements or poor posture, both of which can be influenced by MS symptoms like spasticity or fatigue. Frozen shoulder, medically known as adhesive capsulitis, is another condition characterized by stiffness and pain, severely limiting the shoulder’s range of motion. While the exact cause is often unclear, reduced arm movement due to MS symptoms or pain from other shoulder issues can be a contributing factor.
Osteoarthritis, a degenerative joint disease, can also affect the shoulder joint. While not directly caused by MS, altered biomechanics and increased stress on joints due to MS-related muscle imbalances or mobility aid use can accelerate cartilage wear. People with MS may experience these orthopedic conditions, amplified by neurological symptoms, making accurate diagnosis and management important.
Addressing Shoulder Pain When Living with MS
Effectively addressing shoulder pain in the context of MS requires a comprehensive approach, beginning with an accurate diagnosis to determine the underlying cause. It is important to differentiate between pain directly related to MS lesions, pain resulting from indirect MS symptoms, or pain from co-occurring orthopedic conditions. This diagnostic process often involves a healthcare team, including neurologists, physical therapists, occupational therapists, and pain management specialists.
Physical therapy is crucial for managing shoulder pain. Therapists can design individualized exercise programs that focus on strengthening weakened muscles, improving flexibility, and correcting posture. They may also use techniques such as manual therapy, heat or cold therapy, and electrical stimulation to alleviate pain and improve function. Occupational therapists can provide adaptive techniques and tools to help individuals perform daily activities without exacerbating shoulder pain, such as modifying movements or suggesting ergonomic adjustments.
Pain management strategies can include various approaches, from over-the-counter pain relievers to prescription medications, depending on the type and severity of pain. Localized injections may be considered to reduce inflammation and pain in the shoulder joint. Regular, tailored exercise is important, as it helps maintain muscle strength, flexibility, and overall joint health, which can reduce the likelihood of developing or worsening shoulder pain.