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Multifocal Motor
Neuropathy (MMN)
Patient Care Series
What is Multifocal Motor
Neuropathy (MMN)?
What causes MMN?
How is MMN diagnosed?
The exact cause of MMN is not well understood,
MMN is diagnosed through an extensive physical
Multifocal Motor Neuropathy (MMN) is a rare
but it is thought to be an autoimmune disease
examination by a specialist, usually a neurologist.
muscle disorder that causes the muscles in a
that causes neuropathy, or nerve damage.
Physical exams may uncover weakness,
person’s body to become increasingly weaker over
time. The symptoms of MMN typically develop
slowly, and muscle weakness may progressively
Signals from a person’s brain travel through nerves
to direct muscle movement. Nerves are protected
decreased muscle size and tone, abnormal
reflexes and/or muscle twitching.
by a myelin sheath, which is a protective coating.
Electromyography (EMG) tests may also be
When a person’s immune system mistakenly
performed. EMG tests measure the electrical
In people with MMN, the immune system attacks
attacks the nerves, the protective coating is
activity in a person’s muscles to determine if
the nerves that control muscle movement,
injured or destroyed, which causes nerves to react
their nerves are functioning properly.
mistaking them for harmful infections like bacteria
slowly or become faulty, therefore weakening the
and viruses. As the nerves deteriorate, muscles
muscles they control.
worsen over the course of months or years.
become weaker.
Often, MMN is mistaken for Amyotrophic Lateral
What are the symptoms of MMN?
Certain blood tests may also identify a specific
type of immune cell that attacks the nerves.
What is the prognosis for a
person with MMN?
Sclerosis (ALS), a more common disorder also
MMN causes muscle weakness, which usually begins
known as Lou Gehrig's Disease. Unlike ALS, MMN
in the hands and becomes progressively worse.
can be treated and effectively managed, so it is
Leg and foot weakness may follow. In some cases,
Unlike ALS, MMN can be effectively treated.
important to correctly diagnose the problem.
weakness develops in only one side of the body.
If a person with MMN is correctly diagnosed
Who is affected by MMN?
MMN is very rare, affecting only around 3,000 to
6,000 people in the US. Anyone can develop MMN,
but most patients develop symptoms between the
ages of 30 and 50, and men are three times more
likely to be affected than women.
Other symptoms may include:
Muscle wasting, in which muscles start to shrink
Muscle cramps
Involuntary twitching and spasms
Numbness and tingling
Trouble getting up from a seated position
Difficulty climbing steps
in the early stages of nerve damage, treatment
may reduce symptoms and prevent
permanent disability.
Muscle strength usually gets better within 3 to 6
weeks of treatment, but evidence suggests that
some patients may continue to experience slow,
progressive muscle weakness over many years.
How is MMN treated?
How do I learn more?
MMN is normally treated with Immune Globulin
Contact your doctor or nurse to discuss specific
(IgG) or occasionally drugs that suppress the
questions about IVIg or your personal treatment.
immune system (immunosuppressive therapy).
Steroids and plasmapheresis (blood filtering
procedure) were previously used, but are no
longer considered effective options for MMN.
In some cases where symptoms are very mild,
no treatment may be necessary.
What is Immune Globulin (IgG)?
For additional information, please access
the following:
National Institutes of Health (NIH)
American Academy of Neurology (AAN)
AxelaCare Health Solutions
Immune Globulin (IgG) is made of purified
antibodies, which are proteins made by the
immune system to defend the body against
infection. Since the immune systems in people
All information, treatment descriptions and links are
intended for educational purposes only. Talk to
your doctor before making any lifestyle or
treatment changes.
with MMN can’t make enough of the molecules
that fight infection, they take IgG to supplement
their low or missing antibodies. IgG antibodies are
thought to block the person’s malfunctioning
immune processes to prevent nerve damage.
IVIg is IgG administered intravenously (through
the vein), usually by a specially trained nurse at
a hospital, specialized infusion suite or in the
comfort of the patient’s home.
MMN 1.4