Monoplegia

Paralysis of a single limb

Monoplegia is paralysis of a single limb, usually an arm. Common symptoms associated with monoplegic patients are weakness, numbness, and pain in the affected limb. Monoplegia is a type of paralysis that falls under hemiplegia. While hemiplegia is paralysis of half of the body, monoplegia is localized to a single limb or to a specific region of the body. Monoplegia of the upper limb is sometimes referred to as brachial monoplegia, and that of the lower limb is called crural monoplegia. Monoplegia in the lower extremities is not as common of an occurrence as in the upper extremities. Monoparesis is a similar, but less severe, condition because one limb is very weak, not paralyzed. For more information, see paresis. Many conditions that cause paraplegia or quadriplegia begin as monoplegia. Thus, the diagnosis of spinal paraplegia must also be consulted. In addition, multiple cerebral disorders that cause hemiplegia may begin as monoplegia. Monoplegia is also frequently associated with, and considered to be the mildest form of, cerebral palsy.

There are a number of symptoms associated with monoplegia. Curling of the hands or stiffness of the feet, weakness, spasticity, numbness, paralysis, pain in the affected limb, headaches, and shoulder pain are all considered to be symptoms of monoplegia. Patients of monoplegia typically feel symptoms of weakness and loss of sensation in the affected extremity, usually an arm. Despite these symptoms, the extremity with paralysis continues to maintain a strong pulse. While chronic progressive brachial monoplegia is uncommon, syringomyelia and tumors of the cervical cord or brachial plexus may be the cause. The onset of brachial plexus paralysis is usually explosive where pain is the initial feature. Pain localizes to the shoulder but may be more diffuse, or could be limited to the lower arm. Pain is severe and often described as sharp, stabbing, throbbing, or aching. The duration of pain, which is constant, varies from a span of several hours to 3 weeks. As the pain subsides, weakness usually appears. In addition, chronicle progressive weakness of one leg suggests a tumor of the spinal cord of the lumbar plexus. Fever is often the first symptom of lumbar plexus paralysis, followed by pain in one or both legs. The pain has an abrupt onset and may occur in a femoral or sciatic distribution. Weakness may develop concurrently with pain or be delayed for as long as 3 weeks. Complicated migraine Damage to the corticospinal system results in an inability to activate muscles with enough force or in a coordinated manner, which can lead to paresis, loss of fractional movement, and abnormal muscle tone. An approach called single pulse transcranial magnetic stimulation (spTMS) has also been used to help diagnose motor deficits such as monoplegia.

There is no cure for monoplegia, but treatments typically include physical therapy and counseling to help recover muscle tone and function. Recovery will vary depending on diagnosis of temporary, partial or complete paralysis. Much of the therapies focus on the upper limb due to the fact that monoplegia in the upper limbs is much more common than in the lower limbs. It has been found that intense activity based and goal directed therapy, such as constraint induced movement therapy and bimanual therapy, are more effective than standard care. Studies suggest the less affected hand could provide a template for improving motor performance of the more affected hand, and provides a strong rationale for the development of bimanual training approaches. In addition to that, there is strong evidence to support that occupational therapy home programs that are goal directed could be used to supplement hands on direct therapy. Constraint induced movement therapy (CIMT) is specifically targeted at upper limb monoplegia as a result of a stroke. In CIMT the unaffected arm is restrained, forcing the use and frequent practice of the affected arm. This approach to therapy is carried out during ordinary and daily activities by the affected person. It has been found that CIMT is more effective at specifically improving arm movement than a physiotherapy approach or no treatment at all. This type of therapy has proved to provide an only moderate improvement in patients with monoplegia. Another form of treatment for monoplegia is functional electrical stimulation (FES). It is targeted at patients who acquired monoplegia through incidents such as a spinal cord injury, stroke, multiple sclerosis, or cerebral palsy and utilizes electrical stimulation in order to cause the remaining motor units in the paralyzed muscles to contract. As in traditional muscular training, FES improves the force with which the unaffected muscles contract. For less severely affected patients, FES allows for greater improvement in range of motion than traditional physical therapy.