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5 Causes of Muscle Spasms

What's causing your muscle spasms and how to treat them.

Muscle spasms are common, involuntary contractions of a muscle that can cause stiffness and tightening. Any muscle can spasm, and spasms may occur in part or all of the muscle, or even in a group of muscles.

Muscle spasms (also called spasticity) can be mild or severe. You may be able to see or feel the muscle twitch during a spasm, and it may feel hard or knot-like. They can cause severe pain and make it difficult to move.

Some causes of involuntary muscle spasms are minor, like a mild injury, and can be treated at home. But muscle spasms may also be a symptom of dehydration or heat-related illnesses that require immediate medical attention if they become severe.

Pro Tip

The muscles that are most prone to frequent muscle spasms include the muscles of your arms and legs, hands, and feet. —Dr. Leila Mufdi

Causes of muscle spasms

1. Trauma

Symptoms

  • Muscle spasms
  • Muscle pain and soreness
  • Lack of flexibility of the affected body part
  • Pain with ongoing activity

Muscle spasms can occur after a trauma. For example, a fall or a car accident can injure your muscles and cause spasms. But even minor injuries can trigger muscle spasms, like when restarting an exercise routine. Doing a repetitive motion, like tennis, golf, or hammering can also cause muscle spasms.

When you push your muscles to do more than usual, the muscles develop microtears. Increased blood flow to the area helps the muscles heal and grow but can also lead to increased soreness and stiffness.

If the injury is minor, you may be able to treat muscle spasms at home. Anti-inflammatory medications like ibuprofen can help control pain and decrease swelling in the area, which in turn reduces the risk of spasms. Icing the area for 10 to 15 minutes at a time may also help.

You may also need to scale back your activity for a period of time. Light activities like stretching and walking can help increase blood flow to the muscles and clear substances from the blood that may contribute to cramps after an injury.

More serious injuries should be treated by your doctor. In some cases, your doctor may prescribe a short course of muscle relaxers to treat muscle spasms.

2. Dehydration

Symptoms

  • Muscle spasms and pain
  • Decreased urine or darker urine
  • Feeling faint or weak
  • Dry mouth

Moderate to severe dehydration can decrease the blood flow to your muscles. This increases your risk of muscle spasms and injury because your muscles may tire more easily without enough blood supply.

Many types of problems can lead to dehydration, including vomiting, diarrhea, and fever. Young children and older individuals are at increased risk, as are people with certain medical conditions. For example, uncontrolled diabetes can increase the amount of urine you make, leading to dehydration.

Drinking water or sports drinks is helpful if you have significant vomiting or diarrhea. They’re also recommended if you are exercising or exerting yourself for an extended period of time.

If you have severe dehydration, go to the ER. Very little urine, sunken eyes, and an abnormally fast heart rate are signs of severe dehydration. You may need to be rehydrated with IV fluids.

3. Electrolyte imbalances

Symptoms

  • Muscle spasms
  • Feeling faint or dizzy
  • Feeling like your heart is racing
  • Confusion

Your cells require electrolytes to perform their most basic functions. Examples of electrolytes include sodium, potassium, magnesium, and phosphorus. When these minerals are out of balance, your muscles may be at risk of spasms.

Electrolyte imbalances can be caused by dehydration, vomiting, diarrhea, nutritional deficiencies, and abnormal kidney functions. It can be a temporary response to these issues, or may be more chronic.

If you have an underlying medical condition, like kidney disease, your doctor may order blood tests to see if you have an electrolyte imbalance.

You may need IV fluids to replenish electrolytes. Your doctor may also prescribe an electrolyte supplement if your medication is causing an electrolyte imbalance.

4. Medications

Symptoms

  • Muscle spasms and cramping
  • Changes in the amount of urine you produce
  • Dehydration
  • Muscle damage

Several types of medications can cause muscle spasms and cramping:

  • Blood pressure medications (diuretics) can increase the amount of urine you produce, leading to dehydration.
  • Other types of blood pressure medications may cause electrolyte imbalances by altering the amount of electrolytes your body retains.
  • Statin drugs can sometimes damage muscles and cause spasms.
  • Some medications used to treat depression can cause overstimulation of your nervous system (serotonin syndrome), which may lead to muscle spasms.

In some cases, your doctor will recommend changes to your diet including increasing your fluid intake or increasing certain food groups. Your doctor may also prescribe an electrolyte supplement if your medication is causing an electrolyte imbalance.

In some cases, your doctor may stop or change a medication if it’s causing significant muscle cramps or spasms. Rarely, you may need to go to the ER for more serious side effects such as serotonin syndrome.

5. Heat-related illness

Symptoms

  • Muscle spasms and cramping
  • Increased body temperature
  • Altered mental status
  • Weakness
  • Headache

Heat-related illnesses can cause muscle spasms because they increase your risk of dehydration and electrolyte imbalances. These range in severity from heat cramps to heat exhaustion to heat stroke.

Heat cramps are the mildest form and are often related to strenuous activity and sweating in high temperatures.

Heat exhaustion is more severe. The body temperature is typically elevated to 101℉ to 104℉. You may have headaches and lightheadedness. Your heart rate will typically be higher than usual, and your blood pressure may run lower than usual.

Heat stroke is the most severe form of heat-related illness. It occurs when your body’s ability to cool itself has been overwhelmed. Your body temperature is typically greater than 104℉. Along with the symptoms of heat exhaustion, you may be confused and disoriented.

Heat stroke is life-threatening and requires immediate cooling and medical attention. Anyone can develop a heat illness but the risk is higher for children and elderly people.

Heat cramps and heat exhaustion can be treated by drinking plenty of water and sports drinks. It’s important to try to cool down by removing excessive clothing, moving to a cool place to rest, and placing cool cloths on your skin.

Go to the ER if you have symptoms of heat stroke. These include vomiting, fainting, changes in the temperature and color of your skin, and confusion. Treatment includes aggressive cooling methods (such as cold water immersion) and IV fluids.

Other possible causes

Less common causes of muscle spasms include:

  • Neurologic conditions, such as spinal cord injury, cerebral palsy, and multiple sclerosis.
  • Decreased blood supply related to blockages or spasms of your blood vessels.
  • Rhabdomyolysis.

When to call the doctor

You should visit a doctor if:

  • Your symptoms don’t improve or go away with measures like stretching, increasing water intake, and taking anti-inflammatory medication.
  • You have significant muscle spasms without a clear cause.
  • Your muscle spasms started shortly after a change in the medications you take.

Pro Tip

Many of the treatments for muscle spasms—like stretching, adequate fluid intake, and staying physically active—can also help prevent the development of muscle spasms. —Dr. Mufdi

Should I go to the ER for muscle spasms?

Go to the ER if you have muscle spasms and any of these symptoms:

  • Confusion
  • Persistent vomiting
  • Unable to move part of your body
  • Unable to lower your body temperature after heat exposure
  • Seizures
  • Loss of consciousness

Treatments

At-home care

  • Staying hydrated with water and sports drinks.
  • Stretching or light activities such as walking.
  • Avoiding extreme temperatures.
  • Anti-inflammatory medications such as ibuprofen.
  • Using a foam roller or getting a massage.

Other treatment options

  • IV fluids
  • Changing the medications you take
  • Cooling measures
  • Medications to help control vomiting and diarrhea
  • Muscle relaxers

Dr. Rx

How long muscle spasms last depends on the cause and treatment. For example, with heat cramps, the spasms usually resolve in a day as long as you rest, cool yourself, and drink plenty of fluids. The muscle spasms caused by dehydration should also be relatively brief, if you increase fluids and rest. However, for some causes of muscle cramps, including a significant injury or more chronic electrolyte imbalances, muscle spasms may last days to weeks. —Dr. Mufdi

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