Leg weakness can stem from neurological issues (MS, ALS, Stroke, Guillain-Barré), spinal problems (herniated discs, stenosis, pinched nerves), neuromuscular diseases (muscular dystrophy, myasthenia gravis), vascular conditions (PAD, stroke), infections, autoimmune disorders, or even nutritional deficiencies, with sudden weakness often signaling a medical emergency like a stroke or spinal compression, requiring immediate attention.
Weakness in the legs can be caused by many different conditions, including amyotrophic lateral sclerosis (ALS or called Lou Gehrig's disease), bulging/herniated (slipped) disc, Cauda equina syndrome, Guillain-Barré syndrome, autoimmune diseases, multiple sclerosis, Parkinson's disease, peripheral neuropathy, pinched ...
Guillain-Barre syndrome often begins with tingling and weakness starting in the feet and legs and spreading to the upper body and arms. Some people notice the first symptoms in the arms or face. As Guillain-Barre syndrome progresses, muscle weakness can turn into paralysis.
Several conditions can make your legs feel weak. Spinal problems like herniated discs, pinched nerves, or spinal stenosis. Poor circulation, vitamin deficiencies, and medication side effects can also make your legs feel weak.
There are many conditions generally referred to as neuromuscular diseases—including ALS, spinal muscular atrophy, myasthenia gravis, and muscular dystrophy—that characteristically cause muscle weakness.
Myasthenia gravis (MG) is a chronic autoimmune disorder in which antibodies destroy the communication between nerves and muscle, resulting in weakness of the skeletal muscles.
Early signs of ALS often involve painless muscle weakness, such as tripping or dropping things, along with muscle twitching (fasciculations), cramping, and stiffness (spasticity), commonly starting in limbs but sometimes affecting speech (slurring) or swallowing (choking). Other early indicators include significant fatigue, poor balance, or even uncontrollable laughing/crying (pseudobulbar affect). These symptoms usually begin subtly in one area and spread, affecting daily activities before becoming severe.
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.
The weakness can make your legs feel heavy, as if they are being weighed down by something. They may also ache and hurt. Some people with MS describe it as like having bags of sand attached to their legs. This muscle weakness combined with MS fatigue can be upsetting.
Weakness in the legs can happen for a variety of reasons. These can include DOMS, spinal problems, neuropathy, ALS, stroke, myasthenia gravis, and Guillain-Barré syndrome (GBS). Weakness in the legs may affect one leg or both. Sometimes, leg weakness can signal an underlying medical condition that requires treatment.
Restless legs syndrome (RLS)—also known as Willis-Ekbom Disease—is a neurological condition that causes an irresistible urge to move the legs.
True neurological weakness is different than fatigue or muscle strain. It's an actual loss of muscle strength that reduces or prevents your ability to do numerous tasks and movements. Weakness may be confined to one area or it could affect your entire body.
Eventually, in people with ALS, the brain loses its ability to start and control voluntary movements such as walking, talking, chewing and other functions, as well as breathing. ALS is progressive, meaning symptoms get worse over time.
MRI or CT scan: Detailed images of the spine and legs to check for issues with the discs, nerves, and other tissues. Nerve conduction studies: To see how well electrical impulses are traveling through the nerves. Electromyography (EMG): Tests the electrical activity of muscles to see how well the nerves are working.
Arthritis in the legs can make muscles weak and affect daily life. This happens because of joint pain and swelling. Muscle weakness is caused by pain, less movement, and swelling.
Leg pain can signal various diseases, often related to poor blood flow (like Peripheral Artery Disease (PAD) or Deep Vein Thrombosis (DVT)), nerve issues (like Sciatica, Diabetic Neuropathy, or Restless Legs Syndrome), joint/bone problems (like Arthritis or infections), or muscle conditions, with symptoms varying from exercise-induced cramping to persistent aching, swelling, or numbness.
Three key warning signs of Multiple Sclerosis (MS) often involve vision problems (like blurred vision or pain with eye movement), numbness or tingling sensations, and fatigue, along with balance issues, weakness, and coordination difficulties, though symptoms vary widely and can include cognitive or bladder problems too.
The T25-FW is a quantitative mobility and leg function performance test based on a timed 25-foot walk. It is the first component of the Multiple Sclerosis Functional Composite (MSFC) to be administered at each visit.
What causes sudden leg weakness and shakiness? It can be caused by fatigue, dehydration, low blood sugar, anxiety, poor circulation, or neurological conditions like stroke or MS.
Polymyositis is a rare autoimmune disease that makes your immune system attack your muscles. It's a type of myositis. Myositis causes chronic inflammation in your muscles — swelling that comes and goes over a long time. Eventually, this inflammation makes your muscles feel weak.
A sudden inability to walk typically results from problems affecting the brain, nerves, muscles, or joints—and requires prompt evaluation by a healthcare professional.
In limb-onset, the first symptoms will be in the arms or legs and start with weakness, tripping or stumbling or a reduction in fine manual dexterity. In bulbar-onset, the first symptoms will be difficulty in speaking or swallowing.
Other conditions that can be confused with ALS include:
Nasal inspiratory pressure during a sniff (SNIP) is a respiratory test extensively promoted in Amyotrophic Lateral Sclerosis (ALS) for the assessment of the inspiratory muscle strength.