Tetany is a symptom that involves involuntary muscle contractions and overly stimulated peripheral nerves. It’s caused by electrolyte imbalances — most often low blood calcium levels. It’s important to talk to your healthcare provider if you’re experiencing tetany. Severe cases require immediate medical treatment.


What is tetany?

Tetany is a symptom that involves involuntary muscle contractions and overly stimulated peripheral nerves. It’s caused by electrolyte imbalances.

Tetany can present in many ways. Common, mild signs of tetany include:

Severe signs of tetany include:

The majority of cases of tetany are not life-threatening, but severe cases can be. Severe episodes can sometimes lead to rhabdomyolysis, a potentially life-threatening condition caused by muscle breakdown and muscle death.

If you have mild symptoms of tetany, talk to your healthcare provider. If you have severe symptoms of tetany, call 911 or get to the nearest hospital as soon as possible.


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What is the difference between tetany and clonus?

Clonus is a rhythmic, uncontrolled muscle reflex. It happens due to a permanent lesion in upper motor neurons, which are responsible for carrying the electrical impulses that start and regulate movement. Because of this, healthcare providers check for clonus as part of neurological exams to evaluate the health of a person’s nervous system.

Tetany involves involuntary muscle contractions and other symptoms that result from electrolyte imbalances.

Is tetany a seizure?

Tetany and seizures are distinct conditions, but severe cases of tetany can result in seizures.

A seizure is a medical condition in which you have a temporary, uncontrolled surge of electrical activity in your brain. When that happens, the affected brain cells uncontrollably fire signals to others around them, which overloads the affected areas of your brain.

That overload can cause a wide range of symptoms or effects, including uncontrolled muscle movements.

Tetany typically involves uncontrolled muscle contractions, but it’s caused by an electrolyte imbalance, not an uncontrolled surge of electrical activity in your brain.


Possible Causes

What are the most common causes of tetany?

In general, an electrolyte imbalance causes tetany — often more than one. Electrolytes are substances that have a natural positive or negative electrical charge when they dissolve in water.

Your body is about 60% water, which means nearly every fluid and cell in your body contains electrolytes. They help your body regulate chemical reactions, maintain the balance between fluids inside and outside your cells and more. Your cells use electrolytes to conduct electrical charges, which is how your muscles contract.

The types of electrolyte imbalances that can cause tetany include:

  • Hypocalcemia: Hypocalcemia happens when the levels of calcium in your blood are too low. It’s the most common cause of tetany. The calcium in your blood helps your nerves work, helps make your muscles squeeze together, helps your blood clot if you’re bleeding and helps your heart work properly. Many different health conditions can cause hypocalcemia, but it’s often caused by low levels of parathyroid hormone (hypoparathyroidism) or vitamin D in your body.
  • Hypomagnesemia: Hypomagnesemia happens when the levels of magnesium in your blood are too low. Magnesium is an important electrolyte that’s a key part of many bodily functions. Chronic disease, alcohol use disorder, gastrointestinal issues, kidney issues and other conditions can cause hypomagnesemia.
  • Hypokalemia: Hypokalemia happens when the levels of potassium in your blood are too low. Potassium is an electrolyte that’s critical for the proper functioning of nerve and muscle cells, especially heart muscle cells. Common causes of hypokalemia include diuretics, vomiting and diarrhea and chronic kidney disease.
  • Metabolic alkalosis: Alkalosis happens when your blood and body fluids contain an excess of bases or alkali. Your blood’s acid-base (pH) balance is critical to your well-being. When the balance is off, even by a small amount, it can make you sick. In metabolic alkalosis, there’s an excess of bicarbonate in your body fluids. It can occur in a variety of conditions.
  • Respiratory alkalosis: Respiratory alkalosis happens when you’re breathing too fast or too deeply, causing your lungs to get rid of too much carbon dioxide. This causes the carbon dioxide levels in your blood to decrease, and your blood then becomes alkaline. Hyperventilation due to anxiety can result in tetany.

Care and Treatment

How is tetany treated?

The short-term goal for treating tetany is to fix the electrolyte imbalance. The long-term goal for treating tetany is diagnosing and treating the underlying condition causing it.

If you have a mild case of hypocalcemia, the most common cause of tetany, your provider may suggest the following treatments to restore healthy calcium levels:

  • Calcium supplements.
  • Vitamin D supplements.
  • Magnesium tablets.

If hypocalcemia is more significant, you may need other prescription medication or therapies to treat it.

Severe, acute tetany requires immediate medical treatment in a hospital, which usually involves IV calcium replacement and other therapies. Once you’ve recovered from the acute tetany episode, your provider will address treating the underlying cause of tetany.


How can tetany be prevented?

While it may not be possible to avoid tetany if you have an underlying condition causing an electrolyte imbalance, as with most medical conditions, early detection and treatment can make a significant difference when it comes to your outlook.

If you’re experiencing early signs of tetany, such as numbness around your mouth and muscle spasms, it’s important to talk to your healthcare provider. Treating the electrolyte imbalance early enough can prevent more severe and potentially life-threatening tetany symptoms.

When To Call the Doctor

When should tetany be treated by a doctor or healthcare provider?

If you experience mild signs of tetany, talk to your healthcare provider as soon as possible. You may have an underlying health condition that needs treatment. If you experience severe signs of tetany, such as spasms in your voice box and painful, generalized muscle cramps, you need immediate medical care. Call 911 or get to the nearest hospital.

A note from Cleveland Clinic

While electrolyte imbalances are the main cause of tetany, several — sometimes chronic — conditions can cause electrolyte issues. Because of this, you should talk to your healthcare provider if you have signs of tetany. Replenishing your electrolytes through food and drinks likely won’t fix the tetany if you’re already experiencing signs of it.

Medically Reviewed

Last reviewed on 05/31/2022.

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