- What Are Weak Leg Symptoms?
- True Leg Weakness vs. Fatigue
- Causes of Leg Weakness
- When to Call 911
- What Can You Do at Home Safely?
- How Doctors Evaluate Leg Weakness
- Treatments for Leg Weakness
- Make an Appointment with a Doctor
Leg weakness is a condition that may have a benign cause, like over-exercising, or it may be a symptom of a disease or an underlying health issue. You may notice you are losing leg strength over time, or there might be a sudden weakness in the legs. There are numerous causes of people losing strength in their legs. Unless there is a rapid recovery or no apparent reason for losing leg strength, it is important to see a doctor for testing and diagnosis.
What Are Weak Leg Symptoms?
It may seem evident at first glance that weak leg symptoms are mostly a feeling that the leg is giving out while walking. However, it is not that simple. Many times, weak legs are accompanied by other symptoms besides sudden muscle weakness in the legs. The following is a list of some of the symptoms that are frequently experienced with general leg weakness.
- Muscle pain in the legs
- Reduced muscle strength in the legs
- Stiffness in the leg muscles
- Muscle spasms
- Leg cramps
- Lower back pain
- Legs feel “heavy”
- Leg numbness
- Neuropathic pain
- Knees buckle
- Balance issues are making walking unstable
- Shakiness in the legs
- Tingling feeling in the legs
- Difficulty lifting the leg or foot
- Paralysis
- Difficulty standing
Leg weakness can occur in one or both legs. It can happen suddenly, randomly, or become an ongoing issue.
True Leg Weakness vs. Fatigue
True leg weakness is not due to fatigue. Leg weakness is an objective physical condition characterized by reduced muscle power. It is an actual physical impairment due to something like a herniated disc or sciatica, stroke, or nerve disease.
The following are signs of true leg weakness. It is a physical medical disorder and is not subjective or something based on personal opinion or feelings. No matter how much you try, lifting or moving the leg is impossible.
- Unable to move the leg
- Cannot lift the leg
- Difficulty standing and walking
- Unable to climb stairs or perform other activities requiring lifting the leg against gravity
- Foot drops due to muscle weakness
Leg fatigue is subjective. You may say, “I feel like my legs are too heavy to lift,” but you can lift them. It is usually the result of factors such as overexertion, poor circulation, or dehydration.
Leg fatigue can also be a symptom of general fatigue, in which you feel physically or mentally tired or lacking energy. Leg fatigue differs from leg weakness because you can move the leg and perform tasks, even though it takes real effort.
- Leg feels heavy
- May feel like you are dragging the leg
- Leg aches after activity, but resting returns leg strength
- Legs have normal muscle strength but get fatigued from activity
Causes of Leg Weakness
There are numerous causes of leg weakness, ranging from over-exertion to serious medical conditions like a stroke or disease. If the leg weakness is due to a stroke, there are usually other symptoms like facial drooping, lack of mental awareness, and slurred speech.
A transient ischemic attack (TIA) is called a mini-stroke and could be a forewarning of a stroke. A TIA occurs quickly when a blood clot in the brain blocks blood flow and then rapidly dissolves. It can lead to paralysis on one side, slurred speech, numbness, weakness and paralysis. It is imperative to get medical assistance immediately because the earlier treatment is delivered, the more likely the person is to recover.
Most cases of leg weakness are due to something other than a stroke or TIA, but you still need to see a doctor if any leg weakness develops suddenly or over time. The following are some of the common causes of leg weakness.
1. Stroke
A stroke is a disease in which a blood vessel leading to the brain is blocked or ruptured. A stroke due to a blood clot is called an ischemic stroke. A stroke due to a blood vessel rupturing is called a hemorrhagic stroke. Strokes occur on the left side or right side of the brain or in the brain stem.
Leg weakness is a common symptom of a stroke. The location of the stroke in the brain determines which leg is affected. If the stroke occurs on the left side of the brain, the right leg may experience weakness. Conversely, if the stroke is on the right side, the left leg may be affected. In the case of a stroke in the brain stem, both legs may experience weakness.
2. Transient ischemic attack (TIA)
A TIA, also known as a mini-stroke, is a temporary blockage of blood flow to the brain. Unlike a full stroke, the blockage is usually brief, and the symptoms typically disappear within 24 hours. However, a TIA is a warning sign that a full stroke may occur in the future. Symptoms can include weakness or numbness on one side of the body, including in a leg, and in some cases, paralysis.
3. Sciatica
When you have sciatica, there is compression of the sciatic nerve at some point. The sciatic nerve extends from the lower spine and separates to extend down each leg further. The nerve compression can lead to legs that are painful and weak.
4. Medications
Some medications can lead to loss of strength in the legs due to muscle weakness. Corticosteroids and statins are known to have these side effects.
5. Spine conditions
Various medical issues can develop in the spine and lead to losing strength in the legs. They include a herniated disc, spinal stenosis, arthritis and degenerative disc disease. These medical conditions can lead to loss of leg strength, but other symptoms usually develop too. For example, you may develop back pain from nerve damage, pain that radiates to other body areas, numb legs, or a tingling feeling due to nerve issues.
6. Alcohol use disorder
Excessive alcohol drinking, especially binge drinking, can lead to myopathy, which is skeletal muscle dysfunction. Muscle disease due to alcohol is five times more common than cirrhosis of the liver.
7. Peripheral neuropathy
Peripheral neuropathy occurs when the peripheral nervous system experiences nerve damage. It can develop due to an infection, injury or a disease like diabetes. Diabetes can have neuropathy symptoms or no neuropathy. If it is symptomatic, the lower leg muscles are weak. Leg pain and weakness causing difficulty walking is one symptom. There may be shooting pain, numbness starting in the feet and hands or a freezing or burning feeling.
8. Neuromuscular diseases
Muscle weakness in the legs may indicate that a neuromuscular disease is present. These diseases lead to a loss of functioning in nerves and muscles throughout the body. They include muscular dystrophy, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), myasthenia gravis, and fibromyalgia. These diseases cause several symptoms, including losing strength in the legs, muscle twitching, and muscle stiffness.
9. Toxins
Exposure to environmental toxins or cleaning and pest control products can lead to toxic neuropathy. Nerve pain is felt in the legs and feet or the arms and hands.
10. Injuries
An injury from a fall or vehicle accident can lead to loss of strength in the legs. For example, a torn meniscus in the knee can impede knee functioning. Torn ligaments, broken knee bones, or trapped cartilage can cause your legs to give out due to knee trauma.
11. Arthritis
Arthritis can lead to knee joint disintegration. When the knee joint is unstable, it often leads to losing strength in the legs. The knee joint may be painful, but losing a stable knee structure can also lead to shooting pain in the legs and down to the feet. Recent research has found that some people are more likely to develop muscle weakness as they age due to biological factors.
12. Thyroid conditions
Hyperthyroidism and hypothyroidism can cause muscle weakness or joint and muscle pain.
13. Infections
Bacteria or viruses can cause severe damage if left untreated. The damage may be to the spinal cord, brain or nerves and cause leg weakness.
14. Neurodegenerative diseases
Neurodegenerative diseases are a group of conditions that primarily affect the neurons in the human brain. These diseases are typically progressive, so they get worse over time. They are characterized by a gradual loss of nerve cells, leading to a decline in the individual’s physical and mental abilities.
One common symptom of neurodegenerative diseases is leg weakness, which can lead to balance, stability and mobility issues. Examples of these diseases and disorders include Parkinson’s disease, Alzheimer’s disease, and dementia.
15. Autoimmune diseases
Some causes of leg weakness fall within two or more categories. For example, myasthenia gravis is a chronic autoimmune disorder and a neuromuscular disease.Other autoimmune diseases causing muscle weakness include myositis and rheumatoid arthritis. Guillain-Barré syndrome (GBS) is another condition in which the body’s immune system attacks nerves. It is a rare neurological disorder in which foot weakness often develops first and moves up the legs and the rest of the body.
16. Insect bites
Though rare, sometimes leg weakness develops due to an insect bite. For example, acute compartment syndrome of the leg is a condition in which circulation is compromised due to increased pressure within a closed muscle space. It can progress to weakness, motor paralysis and other issues. While most acute compartment syndrome is due to events like fractures or crush injuries, there are cases in which insect bites cause it.
Lyme disease is a bacterial infection that develops after getting bit by a blacklegged tick (deer tick). Lyme disease can produce neurologic symptoms when the bacteria affect the central or peripheral nervous systems. When peripheral nerves are affected, weakness and numbness in the arms and legs may develop, among many other symptoms.
17. Kidney Disease
Kidney disease may lead to muscle weakness from the retention of uremic toxins due to the kidneys’ struggle to filter the toxins out of the blood and into the urine. The impacts include inflammation and hypercatabolism, in which the body breaks down substances too fast.
Kidney disease can also impair muscle mitochondrial metabolism, a process in which muscle cells produce energy and mitochondrial oxidative stress. The result is reduced muscle strength and physical functioning. Kidney disease may also create an imbalance of electrolytes such as potassium and phosphate and lead to edema, which is fluid retention. The severity of the symptoms is closely associated with the stage of the kidney disease.
18. Physiologic Atrophy
Atrophy is the shrinking or loss of muscle tissue, and it can develop in stages. Physiologic atrophy is one type of muscle atrophy caused by insufficient muscle use. It can develop from lying in bed for an extended period, living a sedentary lifestyle, or disease. Muscle fibers decrease in size, nerve activity decreases, and muscle fatigue develops.
Weakening leg muscles can lead to joint instability and balance and coordination issues. Sarcopenia is the term for losing muscle strength, mass and function in aging people. This is a primary cause of leg weakness and a major cause of disability in seniors as bone density decreases and joint stiffness increases.
19. Iron Deficiency
Leg muscles need a lot of oxygen to function correctly. Iron serves many bodily purposes, including transporting oxygen to the muscles (cellular oxidative metabolism) and supporting mitochondrial functioning needed for muscle energy production. An iron deficiency can interfere with these processes, disrupting how muscles metabolize fuel sources like glucose to generate energy. Iron deficiency may also alter the processing of fats, which store energy, and carbohydrates, which break down into the glucose needed for energy. All of these actions can lead to leg weakness.
20. Electrolyte Imbalance
Electrolytes, the minerals that carry an electric charge when dissolved in body fluids, play a crucial role in muscle functioning. They help move nutrients into cells, remove cell waste and support nerve and muscle functioning. Maintaining a balance of electrolytes, which include potassium, sodium, magnesium, chloride, phosphate and bicarbonates, is essential. Different electrolyte imbalances have different effects on the body. An imbalance of potassium, for example, can lead to symptoms like leg muscle cramping, spasms and weakness. An imbalance may be a high or low level of electrolytes, and the symptoms depend on the type of electrolyte involved.
If sudden leg weakness does not happen regularly and is likely associated with overexertion or vigorous exercise, home treatments like applying hot or cold packs or taking an NSAID can help your body recover. One indication that it is not a severe problem is when you recover quickly.
When to Call 911
Knowing when to call 911 ensures a person experiencing a serious medical condition, like a stroke, gets help as quickly as possible. Some situations involving leg weakness that indicate calling 911 is a good plan include the following.
- Leg weakness is sudden, and there are other symptoms like loss of bladder or bowel control, sudden confusion or vision problems, indicating a possible stroke
- Leg weakness and tingling develop soon after an injury that did not seem serious, indicating there is more bone or tissue damage than realized
- A person experiences an unexpected loss of balance and stability, often resulting in a fall
- An individual suddenly has difficulty walking, which may be accompanied by slurred speech
- There is sudden or developing leg numbness or weakness
- Other symptoms like muscle pain, fever, and shortness of breath accompany the leg weakness
- There is a sudden feeling of intense leg pain, and the leg becomes weak
What Can You Do at Home Safely?
If you cannot raise or move your leg, it is important to see your doctor for a diagnosis. If you have leg fatigue, can move your leg, and the symptoms are mild, there are a few things you can do at home.
- Apply ice for 20 minutes several times a day to relieve pain and swelling
- Apply heat for 20 minutes several times a day to relax tense muscles
- Self-massage the leg muscles to improve blood flow and ease muscle tension
- Rest your legs, avoiding activities that could make weakness worse
A doctor may suggest you do some of these things at home, whether you have leg weakness or leg fatigue. If leg fatigue is persistent or worsens despite these home remedies, consult a doctor.
How Doctors Evaluate Leg Weakness
When you see a doctor for a diagnosis, one of the first clues as to whether you have leg weakness or leg fatigue is your description. If you have leg weakness, you will say something like, “I can’t lift my leg no matter how much I try.” If you have leg fatigue, you would say, “I can lift my leg, but it feels heavy.”
The physician will perform various diagnostic tests after getting your medical history.
- Physical exam to assess leg reflexes, muscle strength on a scale of 0-5, and range of motion
- X-rays of the spine and leg bones to look for damage or other issues, such as a misalignment
- MRI or CT scan to look for issues with the nerves, spinal discs, brain, or other soft tissues
- Nerve conduction study to assess whether electrical impulses are traveling through the nerves properly
- An electromyography (EMG) test is used to assess muscle electrical activity and determine if the nerves are working properly
- Ultrasound test to look for issues with blood flow
- Blood tests to check for things like muscle enzymes, electrolytes, and various medical conditions
The doctor determines which diagnostic studies to perform after reviewing the results of the medical history, your description of the leg issues, and the physical examination. It may take a step-by-step approach where the results of one step indicate that another test is needed. For example, the X-ray shows no bone damage, so the next step is to perform soft-tissue diagnostic tests.
Treatments for Leg Weakness
The best treatment, of course, depends on a doctor’s diagnosis. There are a host of treatment options.
- Guided steroid injections into the spine or knee joints to reduce inflammation
- Physical therapy
- Medications like over-the-counter acetaminophen or ibuprofen for mild pain, and prescription medications for diseases or other underlying causes
- Back brace support until the injury heals
- Exercises to strengthen lower back and leg muscles
- Dietary changes
- Surgery when conservative treatments do not help
A doctor will perform various medical tests to pinpoint the reason for the symptoms of weak legs.
Make an Appointment with a Doctor for Evaluation
Sudden leg weakness is a symptom, and you want to know what is causing the symptom. Since so many causes are related to a spinal condition, you can make an appointment with a spine specialist for diagnosis and treatment. Diagnostic tests include a physical examination, blood tests, motor testing, a neurologic exam, MRI, X-rays, myelogram, and CT scan.
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