What are the other Names for this Condition? (Also known as/Synonyms)

• MADSAM (Multifocal Acquired Demyelinating Sensory and Motor Neuropathy)
• Multifocal Acquired Demyelinating Sensory and Motor Neuropathy (MADSAM)

What is Lewis-Sumner Syndrome? (Definition/Background Information)

• Lewis-Sumner Syndrome (also known as Multifocal Acquired Demyelinating Sensory and Motor Neuropathy) is a neurological condition affecting primarily the arms and hands (upper limbs)
• The symptoms are a result of inflammation of the nerves leading to the upper body and the destruction of the fatty covering that protects the nerves (myelin sheath)
• Lewis-Sumner Syndrome is an acquired disorder, and the exact cause of the condition is not known
• Lewis-Sumner Syndrome may be difficult to distinguish from other forms of demyelinating neuropathies, but diagnosis may be possible through nerve conduction studies or a specific type of imaging test, called MRI with T2 STIR
• Treatment with intravenous immunoglobulin (IVIg) therapy has been successful in reducing the symptoms of the disorder

(Source: Lewis-Sumner Syndrome; Genetic and Rare Disease Information Center (GARD) of National Center for Advancing Translational Science (NCATS), USA.)

Who gets Lewis-Sumner Syndrome? (Age and Sex Distribution)

• Lewis-Sumner Syndrome is a rare acquired disorder. The presentation of symptoms may occur at any age, although most cases are reported as adult-onset
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Lewis-Sumner Syndrome? (Predisposing Factors)

• Use of anti-TNFα  medication may be a risk factor for Lewis-Sumner Syndrome
• Currently, no other risk factor has been clearly identified for this condition

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Lewis-Sumner Syndrome? (Etiology)

• Lewis-Sumner Syndrome is an acquired condition. The exact cause of the syndrome is not known
• In some cases, Lewis-Sumner Syndrome can be a side-effect of a type of medication called antagonists of TNF-alpha (anti-TNFα)
• This type of medication may be used for treatment of arthritis and inflammatory bowel disease

(Source: Lewis-Sumner Syndrome; Genetic and Rare Disease Information Center (GARD) of National Center for Advancing Translational Science (NCATS), USA.)

What are the Signs and Symptoms of Lewis-Sumner Syndrome?

The signs and symptoms of Lewis-Sumner Syndrome may vary among affected individuals in type and severity.

• Hand and arm weakness
• Loss of reflexes in the upper limbs (areflexia) 
• Loss of feeling in the hands and fingers (neuropathy) 
• Tingling in the hands and fingers 
• Pain in the upper limbs

The condition may also affect the legs and feet 

(Source: Lewis-Sumner Syndrome; Genetic and Rare Disease Information Center (GARD) of National Center for Advancing Translational Science (NCATS), USA.)

How is Lewis-Sumner Syndrome Diagnosed?

Lewis-Sumner Syndrome may be diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests
• Nerve conduction studies
• Imaging studies (including MRI T2 STIR for clear view of the affected nerve networks, such as the brachial plexus nerve network)
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Lewis-Sumner Syndrome?

The complications of Lewis-Sumner Syndrome may include:

• Difficulty with movement
• Reduced quality of life

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Lewis-Sumner Syndrome Treated?

• The treatment most commonly used for Lewis-Sumner Syndrome is intravenous immunoglobulins (IVIg). This type of therapy uses a mixture of antibodies delivered through an IV to help alleviate the symptoms of the disorder, and is successful in 80% of cases
• For individuals who do not respond to IVIg, treatment with subcutaneous immunoglobulins or plasma exchange have proved effective

(Source: Lewis-Sumner Syndrome; Genetic and Rare Disease Information Center (GARD) of National Center for Advancing Translational Science (NCATS), USA.)

How can Lewis-Sumner Syndrome be Prevented?

The exact cause of Lewis-Sumner Syndrome is not known, and no methods or guidelines exist for its prevention

• In some cases, the condition may be associated with anti-TNFα medication used for arthritis and inflammatory bowel disease
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired disorders

Regular medical screening at periodic intervals with tests and physical examinations are recommended.

What is the Prognosis of Lewis-Sumner Syndrome? (Outcomes/Resolutions)

• The prognosis of Lewis-Sumner Syndrome is dependent upon the severity of the signs and symptoms and associated complications, if any
• In many cases, treatment with immunoglobulins is reported to effectively reduce the signs and symptoms of the condition 
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Lewis-Sumner Syndrome:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/