
Neuromuscular Disorders
Who is Impacted?
- Although it can occur at any age and in both genders, CIDP is more common in young adults, and in men more so than women.
How is CIDP diagnosed?
- CIDP is difficult to diagnose, because it is a rare disorder. Prescribers tend to rule out more common diseases prior to reaching a CIDP diagnosis.
- To reach the diagnosis, several tests and exams are utilized. The prescriber will likely take a detailed medical history and ask to explain symptoms as detailed as possible, especially how it started, and whether or not they have progressed. For a CIDP diagnosis, symptoms must be experienced for a minimum of eight weeks.
- Additional tests may ordered to examine other parts of the body. A nerve conduction test can determine how quickly nerve impulses move through the body. This reading can help in the future to determine if these impulses are improving or worsening.
- Likewise, a spinal fluid analysis and blood or urine tests can help rule out other possible causes for experienced symptoms.
How is CIDP treated?
- After a CIDP diagnosis has been determined, a referral will be required to see a specialist. These physicians specialize in treating autoimmune or immune-mediated disorders and have additional experience in lifestyle changes that may help slow down the progression of the disease. The goal of treatment for CIDP is to stop the attacks on the myelin to reduce the progression of symptoms.The first line of treatment are corticosteroids, specifically prednisone.
- Other treatments include:
- Plasma exchange
- IVIG
- Immunosuppressants
- Stem cell transplant
What is GBS?
Guillain-Barré syndrome (GBS) is a disorder in which the body's immune system attacks part of the peripheral nervous system. The first symptoms of this disorder include varying degrees of weakness or tingling sensations in the legs. In many instances the symmetrical weakness and abnormal sensations spread to the arms and upper body.
Who is impacted?
No one yet knows why Guillain-Barré affects some people and not others. In addition, it is unclear exactly what sets the disease in motion.
How is GBS diagnosed?
Guillain-Barré is called a syndrome rather than a disease because it is not clear that a specific disease-causing agent is involved. A syndrome is a medical condition characterized by a collection of symptoms (what the patient feels) and signs (what a doctor can observe or measure). The signs and symptoms of the syndrome can be quite varied, so doctors may, on rare occasions, find it difficult to diagnose Guillain-Barré in its earliest stages.
How is GBS treated?
There is no known cure for Guillain-Barré syndrome. However, there are therapies that lessen the severity of the illness and accelerate the recovery in most patients. There are also a number of ways to treat the complications of the disease.
Currently, plasma exchange (also called plasmapheresis) and high-dose immunoglobulin therapy (IVIG) are used. Both of them are equally effective, but immunoglobulin is easier to administer.
Plasma exchange is a method by which whole blood is removed from the body and processed so that the red and white blood cells are separated from the plasma, or liquid portion of the blood. The blood cells are then returned to the patient without the plasma, which the body quickly replaces. Scientists still do not know exactly why plasma exchange works, but the technique seems to reduce the severity and duration of the Guillain-Barré episode. This may be because plasmapheresis can remove antibodies and other immune cell-derived factors that could contribute to nerve damage.
In high-dose IVIG therapy, doctors give intravenous injections of the proteins that, in small quantities, the immune system uses naturally to attack invading organisms. Investigators have found that giving high doses of these immunoglobulins, derived from a pool of thousands of normal donors, to Guillain-Barré patients can lessen the immune attack on the nervous system. Investigators do not know why or how this works, although several hypotheses have been proposed.
What is MMN?
Multifocal Motor Neuropathy (MMN) is a rare disorder in which focal areas of multiple motor nerves are attacked by one’s own immune system. Typically, MMN is slowly progressive, resulting in asymmetrical weakness of a patient’s limbs. Patients frequently develop weakness in their hand(s), resulting in dropping of objects or sometimes inability to turn a key in a lock. The weakness associated with MMN can be recognized as fitting a specific nerve territory.
Who is impacted?
The prevalence of this very rare disease is estimated to be 0.6 cases in every 100,000 people, which makes it even more rare than Guillain-Barre Syndrome, a spontaneously self-limiting disorder in which 1-2/100,000 cases occur each year in North America and Europe.
How is MMN diagnosed?
The diagnosis of MMN is a clinical one which depends on demonstrating that the patient:
- has a purely motor disorder affecting individual nerves
- does not have UMN (upper motor neuron) signs such as brisk reflexes at the knees or ankles or spasticity in the limbs
- has no difficulty speaking or swallowing
- has no sensory deficits
- has evidence of focal areas of nerve in which electrical impulses are slowed or blocked (conduction block) which can be detected on electrophysiology tests
How is MMN treated?
It is now established that intravenous immunoglobulin (IVIG), a preparation of antibodies obtained from healthy volunteers, can be readily given through an arm vein and provides benefit to patients with MMN. It is the only treatment for this disorder that is approved by the Federal Drug Administration (FDA) and regulatory agencies in Europe and Canada. IVIG can lead to improved motor function in most patients with MMN, with the response varying from minimal to very large. Early treatment shortly after symptom onset is always more effective. The treatment usually does not completely reverse all of the symptoms, and those patients who do respond will require repeated treatments to maintain their improvement. Patients usually require retreatment every 2-5 weeks and over time may need increased doses of IVIG.
What is Myasthenia Gravis?
The most common form of myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder that is characterized by fluctuating weakness of the voluntary muscle groups.
Who is impacted?
The prevalence of MG in the United States is estimated to be approximately 0.02%. However, MG is probably under diagnosed and the prevalence may be higher. Myasthenia gravis occurs in all races, both genders, and at any age. MG is not thought to be directly inherited nor is it contagious. It does occasionally occur in more than one member of the same family.
How is MG diagnosed?
A diagnosis can be confirmed in several ways, including the following:
- Anti-MuSK Antibody testing----a blood test for the remaining 15% of MG patients who have tested negative for the acetylcholine antibody. These patients have seronegative (SN) MG. About 40% of patients with SNMG test positive for the anti-MuSK antibody. The remaining patients have unidentified antibodies causing their MG.
- Office Tests—Sleep, Ice Pack and Edrophonium tests are examinations performed by specialists to evaluate an improvement in strength that may be consistent with MG.
- Electromyography— (EMG) studies can provide support for the diagnosis of MG when characteristic patterns are present. Repetitive Nerve Stimulation is used to check for a pattern of response that is characteristic of MG.
- Single Fiber EMG— studies can provide support for the diagnosis of MG when characteristic patterns are present. The single fiber EMG and AChR antibody test are primary tests used to confirm a clinical diagnosis of MG.
- Acetylcholine Receptor Antibody— a blood test for the abnormal antibodies can be performed to see if they are present. Approximately 85% of MG patients have this antibody and, when detected with an elevated concentration the AChR antibody test is strongly indicative of MG.
Often times, all of these tests are negative or equivocal in someone with a story and examination still seem to point to a diagnosis of MG. A clinician skilled in recognizing MG and distinguishing MG from other conditions would need to determine if such a patient has MG or another disorder.
How is MG treated?
There are many effective treatments for myasthenia gravis. Spontaneous improvement and even remission (although uncommon) may occur without specific therapy.
- Anti-acetylcholinesterase agents.
- Corticosteroids (e.g., prednisone) and immunosuppressive agents
- Plasmapheresis, or plasma exchange, may be useful in the treatment of MG also. This procedure removes the abnormal antibodies from the plasma of the blood. The improvement in muscle strength may be striking, but is usually short-lived, since production of the abnormal antibodies continues. When plasmapheresis is used, it may require repeated exchanges. Plasmapheresis may be especially useful during severe MG weakness or prior to surgery.
- Intravenous immune globulins (IVIG) are sometimes used to affect the function or production of the abnormal antibodies also.
What is Myositis?
- Myositis means inflammation of the muscles required to move your body. There are two specific kinds of myositis: polymyositis and dermatomyositis. Polymyositis is responsible for causing muscle weakness especially in the areas closest to the trunk of the body. Dermatomyositis is responsible for causing muscle weakness as well as a skin rash.
Who is impacted?
- Patients who have an injury, infection or autoimmune disease can be impacted.
How is myositis diagnosed?
- Myositis is typically diagnosed by a physical exam, lab and imaging tests, and possibly a muscle biopsy if necessary.
How is myositis treated?
- There is currently no cure for these conditions, but they can typically be treated with a high dose corticosteroid for symptom control.
- Patients may also benefit from physical therapy, exercise, heat therapy, assistive devices, rest and other alternative medications.