Monoplegia is a form of paralysis that affects just one limb. It is almost always the product of cerebral palsy, though a limited number of other medical conditions may cause monoplegia. Because monoplegia is rare, it is still poorly understood, and research into ideal treatments, the progression of the disease, and best practices for assisting patients is still in its infancy.
Monoplegia is paralysis limited to a single limb—usually an arm. Occasionally, the paralysis is even further limited, to just a single muscle. Though this can substantially impede function, most people with monoplegia are able to care for themselves, perform daily tasks, and find ways to work around their symptoms. In people with cerebral palsy, monoplegia is considered a sign of a good prognosis, since it's one of the most minor symptoms of the disease.
Most people with monoplegia experience a gradual deterioration in functioning, beginning with weakness or limpness in the affected limb. Over time, the effects intensify, eventually leading to full or partial paralysis of the affected limb.
Monoplegia is the product of damage to parts of the brain that control the affected area. Less commonly spinal cord damage may also be implicated, but this is more likely to cause other symptoms, such as paraplegia or quadriplegia.
Cerebral palsy is the leading cause of monoplegia. Indeed, so heavily associated with cerebral palsy is this symptom that some doctors consider it a telltale sign of CP. Rather than a single disorder, cerebral palsy is actually a group of related neurological disorders that typically manifest early in life. It's the most common movement disorder in children, affecting about .2% of all births. A number of injuries and infections can cause CP, including oxygen deprivation at or immediately following birth, toxoplasmosis, rubella, and exposure to high levels of toxins such as mercury.
Cerebral palsy appears in childhood, not midlife. Most children with cerebral palsy have other symptoms, so adults who only experience monoplegia likely have another condition, not undiagnosed CP. Some other symptoms of cerebral palsy include:
A limited number of other disorders can cause monoplegia. Those include:
Symptoms of monoplegia are typically limited to a single limb, though other symptoms of cerebral palsy will likely be present. Symptoms of monoplegia include:
Treatment for monoplegia depends on its cause. When the product of cerebral palsy, monoplegia may change or even remit over time, but cerebral palsy itself has no cure. Treatments for CP include a wide range of medications, physical therapy, surgery, assistance integrating into the community, biofeedback, and some alternative treatments. Because CP is incurable, a number of promising experimental treatments have emerged in recent years, though results have varied and there is still no single treatment that works for every patient.
People with monoplegia due to other causes have a range of treatment options. Those include: