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Diffuse Muscle Weakness

April 6, 2021

We're sorry your muscles feel weak.

The word "diffuse" means "widespread" and refers to symptoms that are not localized to just one or a few areas. Instead, it is more or less all over, or at least in many areas. This guide is intended for people who feel weak all over.

This guide will deal with true weakness, meaning reduced power in the muscles. Symptoms of muscle weakness include difficulty rising from a chair, brushing your hair, lifting an object off a high shelf, or dropping things. It might cause drooping of an eyelid or difficulty smiling, depending on which muscles are weak.

People with other symptoms, such as fatigue (tiredness, feeling exhausted), sleepiness, or depression, will often say they feel weak and it can be hard to distinguish some of these from actual muscle weakness. So, if you aren't sure whether this guide is for you, start the guide and see if the symptoms it covers apply to you.

One more point before we move on: some people feel weak due to pain. Weakness and pain can certainly go together, but this guide is not focused on causes of diffuse pain.

Okay, let's get started.

The goal of this guide is to provide information while awaiting evaluation with your doctor, or for additional information after you have seen him or her. Please keep in mind that this guide is not intended to replace a face-to-face evaluation with your doctor.

The diagnoses discussed are among the most common that could explain your symptoms, but the list is not exhaustive and there are many other possibilities. In addition, more than one condition may be present at the same time. For example, a person who feels weak because of poor conditioning could also have a thyroid condition.

First off, it's important to get emergency care if your symptoms sound like a dangerous condition or an immediate threat to your health.

Examples include

- Sudden weakness on one side of your body

- New diffuse weakness with fever or rash

- Sudden inability to move either or both legs

Are you experiencing any of these types of symptoms?

Yes, I have one or more of these symptoms.

No, I don't have these symptoms.

That's good. Okay, now let's find out where you feel weakness.

Is your weakness in the upper arms/shoulders and upper legs/thighs? People with these symptoms usually say it's tough to get out of a chair without using their hands or cannot hold their arms over their heads to brush their hair or reach a high shelf.

Yes, that sounds like me!

No, that's not the problem for me.

Okay. That's helpful to know because it makes certain conditions less likely.

Does your weakness involve the hands or feet?

Yes, I'm weak in the hands and/or feet.

No, I'm not weak in the hands and/or feet.

Okay. There are a number of reasons that these muscles may become weak. Certain medications can do it, and that's one of the most common causes. While there's a long list of medications that occasionally cause muscle weakness, the most common are corticosteroids (such as prednisone) and statin-type cholesterol-lowering medicines (such as lovastatin, simvastatin or atorvastatin).

Have you started any new medications lately? Are you taking a corticosteroid medication or a statin?

Yes, I take one of those or just started a new medicine.

Nope, no new medicines and none of those you mention.

Okay. But, it may still be worth reviewing the medicines you are taking to see if any may be to blame for your weakness.

Next, it's important to consider common hormonal or metabolic causes of muscle weakness. Examples include thyroid disorders, too much or too little calcium in the blood, and excessive cortisol (a hormone produced by the adrenal gland).

Do you have any of the following symptoms?

- Newly dry skin, a hoarse voice, intolerance of cold temperature, constipation (common symptoms of an underactive thyroid)

- Loss of appetite, nausea, constipation, frequent urination, increased thirst (common symptoms of high blood calcium)

- Muscle cramps, spasms or twitching, numbness, tingling, feeling irritable (common symptoms of low blood calcium)

Yes, I have noticed some of those symptoms!

No, none of that sounds familiar.

Your medication could be contributing to or causing your weakness. But don't make any changes to your medicines without your doctor's approval; instead, talk to him or her about your symptoms and about the possibility that your medication is the cause.

Next, it's important to consider common hormonal or metabolic causes of muscle weakness; examples include thyroid disorders, too much or too little calcium in the blood, and excessive cortisol (a hormone produced by the adrenal gland).

Do you have one or more of the following symptoms?

- Recent onset of dry skin, a hoarse voice, intolerance of cold temperature, constipation (common symptoms of an underactive thyroid)

- Loss of appetite, nausea, constipation, frequent urination, increased thirst (common symptoms of high blood calcium)

- Muscle cramps, spasms or twitching, numbness, tingling, feeling irritable (common symptoms of low blood calcium)

- Unexplained weight gain, puffy face, acne, purple lines on the abdomen or thighs (common symptoms of high cortisol)

Yes, I have noticed some of those symptoms!

No, none of that sounds familiar.

Okay, good, perhaps your weakness is due to something else.

Some rarer causes of diffuse muscle weakness include muscle inflammation, so called "idiopathic inflammatory muscle diseases." These are idiopathic conditions (that is, they are of unknown cause) and may be due to a mistaken attack of the immune system on muscle tissue.

Do you have marked weakness of the upper arms and thighs along with any of the following?

- A rash over the knuckles, eyelids, or chest

- Shortness of breath

- Fever

Yes, that sounds like me.

Nope, doesn't sound familiar.

The symptoms you're reporting could be due to a hormonal or metabolic problem (such as an underactive thyroid, excessive cortisol, or a calcium problem).

These are important conditions to diagnose and treat. And most can be detected by simple blood or urine tests, so be sure to talk to your doctor about all of your symptoms.

There are other possibilities. For example, some rare causes of diffuse muscle weakness include muscle inflammation, the so called "idiopathic inflammatory muscle diseases." These are idiopathic conditions (that is, they are of unknown cause) and may be due to a mistaken attack of the immune system on muscle tissue.

Along with marked weakness of the upper arms and thighs, do you notice one or more of the following?

- A rash over the knuckles, eyelids, or chest

- Shortness of breath

- Fever

Yes, that sounds like me.

Nope, doesn't sound familiar.

Okay, that's helpful to know.

So, does your weakness involve the hands or feet?

Yes, I'm weak in the hands and/or feet.

No, I'm not weak in the hands and/or feet.

Okay, just a few more questions that we may not have covered yet.

Does your weakness involve the facial muscles, such as a drooping eyelid or inability to make a smile?

Yes, I do have problems like that.

No, the muscles in my face seem to be okay.

If your weakness is primarily in the hands and feet, a nerve disease (neuropathy) or neuromuscular disease (a disorder of the nerve-muscle connection) could be to blame.

The most common example of neuropathy causing hand weakness is carpal tunnel syndrome. That's a condition in which a large nerve (called the median nerve) is compressed as it travels through the narrow canal of bones in the wrist. You'll have a chance to read more about carpal tunnel syndrome at the end of this guide.

If you also have weakness in your feet, another type of neuropathy could be to blame. People with diabetes often have neuropathy of the hands and feet that causes numbness, tingling, and, sometimes, weakness. It's important to have your hand and/or foot weakness evaluated for possible neuropathy or neuromuscular disease.

Okay, just a few more questions that we may not have covered yet.

Does your weakness involve the facial muscles, such as a drooping eyelid or inability to make a smile?

Yes, I do have problems like that.

No, the muscles in my face seem to be okay.

Okay, good. Just one more question:

Has your weakness been something you've noticed all your life? For example, were you able to keep up with the other kids on the playground? Have you had trouble getting up from a squatting position ever since you were a child?

Yes, I've had weakness problems all my life.

No, those are not problems I've had.

Conditions that cause weakness of facial muscles include myasthenia gravis, Bell's palsy, and amyotrophic lateral sclerosis (ALS, also called Lou Gehrig's Disease), among other conditions. See your doctor and describe as precisely as you can the facial muscle symptoms you are having.

Just one more question:

Has your weakness been something you've noticed all your life? For example, were you able to keep up with the other kids on the playground? Have you had trouble getting up from a squatting position ever since you were a child?

Yes, I've had weakness problems all my life.

No, those are not problems I've had.

Okay, that's good. Lifelong weakness could be a sign of muscular dystrophy or some other serious nerve or muscle disease.

Click here to finish.

You may have a form of muscular dystrophy (MD) or another genetic disease affecting muscles. There are many different types, some affecting the face, others affecting the shoulders, while others affect just about all of the muscles. These conditions are usually diagnosed during childhood, but occasionally people first learn they have MD as young adults or middle-aged adults.

Click here to finish.

From your answers, you could have dermatomyositis or polymyositis. As mentioned before, these are conditions of unknown cause in which inflammation develops in the muscles, perhaps due to a faulty immune system.

See your doctor about this. He or she will review your symptoms, perform a physical examination, and may recommend some basic blood tests. With these, your doctor may be able to tell you whether one of these conditions is likely.

Additional testing, such as an electromyogram, nerve conduction testing, and a muscle biopsy, may be needed to confirm the diagnosis.

Click here to finish.

You've reached the end of this guide. We hope this guide has been useful to you!

It can take a bit of time to determine why a person has diffuse muscle weakness. Figuring out a specific cause can lead to specific medications or other treatments that help. However, in some cases, no cause is ever found. Even so, physical therapy and a conditioning program may be able to restore some of the lost strength.

Some of the more common causes of weakness have been covered here. Fortunately, many of these are highly treatable. The cause of your diffuse weakness may not have been covered here, so be sure to review your situation with your doctor.

Whatever the explanation, we hope your weakness resolves completely and that your health remains excellent!

You need immediate medical evaluation. A stroke, infection or spinal cord problem could be to blame. If you aren't sure about whether it's an emergency, contact your doctor now to talk it over. You can always come back to this guide later.

Disclaimer:

As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

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