What Is Muscle Weakness?
Feeling weak is not all that
uncommon. Whether you are ill or simply need rest, muscle weakness happens to
nearly everyone at some point in their life.
The definition of true muscle
weakness, however, is when your full effort does not produce a normal muscle
contraction or movement. You may hear it also referred to as reduced muscle
strength, muscular weakness, or weak muscles.
A voluntary muscle contraction is
usually generated when the brain sends a signal through the spinal cord and
nerves to a muscle. If the brain, the nervous system, the muscles, or the
connections between are injured or affected by disease, the muscle won’t
contract normally and muscle weakness is the resultant symptom.
This is different from the
weakness you may feel as a result of a tough workout, for instance. The
difference is that a workout will exhaust muscles and there is recovery with
rest, but true muscular weakness is a sign of something deeper.
Potential Causes of Muscle Weakness
There are many possible
underlying causes for muscle weakness. Possible causes include:
- chronic fatigue syndrome
- muscular dystrophy
- Graves disease
- Guillain-Barré syndrome
- hypotonia (lack of muscle tone,
usually present at birth)
- Lou Gehrig’s disease
- myasthenia gravis (an autoimmune
and muscular disorder)
- neuralgias (sharp burning or pain
in one or more nerve)
- peripheral neuropathy (nerve
- rheumatic fever
- West Nile virus
- hypercalcemia (elevated calcium
in the blood)
- botulism (a rare and serious
illness caused by the bacterium Clostridium botulinum)
- polymyositis (chronic muscle
- prolonged bed rest or
Diagnosing the Underlying Cause of Muscle Weakness
When you experience muscle
weakness and there is no normal, logical explanation for it, make an
appointment to see your doctor. Your doctor will ask you questions about the
weakness, how long you have had it, and what muscles are affected. The
evaluation will also determine if muscle atrophy is present.
Your doctor will also check your
reflexes, sensation, and muscle tone. If further investigation is needed, the
doctor may order tests including:
- CT scan
- nerve tests
- electromyography (tests nerve
activity in the muscles)
- blood tests
Treatment Options for Muscle Weakness
Once the cause of your muscle
weakness is determined, your doctor can decide on proper treatment. The
treatment will depend on the underlying problem and the severity of the symptoms.
In some cases, physical therapy may be helpful. In others, medication may be
the best option for relief.
a Potential Emergency Situation
In some cases, muscle weakness
can be a sign of something very serious like a stroke. If you experience any of
the following symptoms, call 911 immediately.
- Any sudden onset of muscle
weakness, such as being unable to move an arm or leg, or problems walking,
standing, or sitting upright.
- Any sudden onset of being unable
to smile or make facial grimaces.
- Any chest muscle weakness
resulting in difficulties breathing.