Neuromuscular medicine is the practice of medicine that involves the care of patients with disorders of the peripheral nervous system (PNS) and its connections with the central nervous system. The PNS includes the motor and sensory neurons, peripheral nerves, neuromuscular junctions, and muscles. The care of patients with neuromuscular symptoms and signs includes physical examination, clinical investigation, diagnosis, management, and counseling for patients and their families. Neuromuscular medicine requires training and knowledge beyond that expected of a general neurologist or physiatrist. Electrodiagnostic medicine is an essential part of neuromuscular medicine.
Nerve roots exit the spine and enter the body. If one of these roots is sick or injured in the area where it leaves the spine, it is called a radiculopathy. Some disease states can cause this, but more often it is a mechanical cause like a herniated disc, bone spur, or stretching event. This can cause numbness, tingling, pain, and weakness in the part of the body controlled by that root.
After taking the patient’s history, we will perform a specific neurological examination which would guide further diagnostic and/or therapeutic steps. A NCS/EMG, and/or neuroimaging such as an MRI might be needed to diagnose radiculopathy. Treatment can include medication, physical therapy, steroid injection in the spine, and in the most serious cases even surgery.
Inflammatory polyradiculopathies are also included in this section, Acute and Chronic Inflammatory Demyelinating Polyradiculoneuropathy (AIDP & CIDP). The acute form requires emergent evaluation and treatment in the hospital setting with subsequent followups in the outpatient setting for monitoring. The Chronic form or CIDP can be from acute onset or from an insidious initial presentation. A NCS/EMG is used to ascertain diagnoses and is used to monitor progression and/or response to therapy. Immunomodulatory therapy and other interventions are evidenced to help in this type of inflammatory disorders.
Plexopathy is a disorder affecting the network of nerves given by the nerve roots exiting the spinal cord and prior giving the nerves that control our arms or legs. There are two network of nerves, the Brachial Plexus and the Lumbosacral Plexus. Disorders of this structures can cause weakness, numbness, and atrophy in a limb.
The sciatic nerve is the longest nerve in the body, running from the hips down to the knees. Nerve fibers in the sciatic nerve arise from the lumbar spine. Lumbosacral radiculopathy often causes pain that radiates down the back of the leg. This pain pattern is referred to as sciatica. Rarely, other conditions may cause pain radiating in the sciatic distribution, but the most common cause is radiculopathy. Anyone can get sciatica. It typically affects people between the ages of 30 and 50.
There are various treatments for sciatica, depending on the severity of the problem and the underlying cause. Physical therapy or special exercises can be used to help alleviate the pain. In more extreme cases surgery may be required.
Single nerves can be affected in the body for various reason, be the most notorious, Carpal Tunnel Syndrome (CTS). In CTS the median nerve at wrist gets injured. Other types of mononeuropathies include injury to the radial nerve causing “wrist drop”, injury to the ulnar nerve at the elbow “tennis elbow syndrome”, injury of the tibial nerve at the ankle causing “tarsal tunnel syndrome”, and many others. NCS/EMG is paramount in extended additional diagnostic tool to a history and exam, and can also help quantifying the degree of injury.
Mononeuritis multiplex, also known as mononeuropathy multiplex or multifocal neuropathy, is a type of peripheral neuropathy. It happens when there is damage to two or more different nerve areas. Mononeuritis multiplex is actually a group of symptoms rather than its own disease. Its symptoms include numbness, tingling, abnormal sensation, lack of sensation, difficulty to control movement, or an inability to move a part of the body.
Anyone can have mononeuritis multiplex, but people with diabetes, mellitus or connective tissue diseases are more likely to get it. Another common cause includes a lack of oxygen caused by decreased blood flow. A common cause is from vasculitis. This is an inflammation around some blood vessels that can affect the vasa nervorum, or blood vessels around certain nerves. This can be seen in many disorders including: polyarteritis nodosa, rheumatoid arthritis, systemic lupus erythematosus, Wegener’s granulomatosis, and scleroderma, to name a few.
Neuromuscular Junction Disorders
Neuromuscular junction transmission defect is a problem with communication from the nerve to the muscle. Normally, acetylcholine (a neurotransmitter) is released from the end of the nerve and attaches to the muscle causing contraction of the muscle. A defect in neuromuscular transmission can occur when there is a deficit in the amount of acetylcholine released from the nerve or acetylcholine attachment to the muscle is blocked. This type of disorder manifest with a particular weakness presentation. A specific type of NCS called Repetitive Nerve Stimulation (RNS) is used to evaluate for this type of disease causing weakness. Treatments are available with close monitoring of response be beneficial to patients with this disease.
Peripheral neuropathy is a diffuse nerve disorder. It may cause numbness, tingling, and weakness. It can also cause pain. These symptoms usually start at the end of the longest nerves in the body and so first affect the feet and later the hands. This is sometimes called the “stocking-glove” pattern. The symptoms usually spread slowly and evenly up the legs and arms. Other body parts might also be affected. There are multiple causes for peripheral neuropathy and a battery of laboratory testing in conjunction with NCS/EMG are used to diagnose and identify cause. Many times this particular disorder despite our current knowledge, a cause is not able to be identified.
Neuronal Cell Disorders
Sensory Neuronopathies are disorders in where the cell bodies of the sensory nerves are affected by various processes including our own immune system, by toxins such as chemotherapy, by infections, and at times a cause can not be identified. Patients experience painful paresthesias and dysesthesias, abnormal sensations. Strength is preserved.
Motor Neuron Disorders affect the cell bodies of motor nerves wtih the most notorious form being Amyotrophhic Lateral Sclerosis(ALS) or Lou Gehrig’s Disease. This disorders manifest with weakness and atrophy of muscles. Sensation is preserved.
Myopathies and Muscle Disorders
Myopathies are diseases that affect skeletal muscles, making a person feel weak. Other possible symptoms are muscle pain, cramps, and stiffness. Myopathies can be caused by genetic defects, metabolic disorders, inflammation, medications, as well as a wide range of disease. Anyone can get a myopathy. Some develop at an early age, while other types develop later in life.