Myasthenic and Cholinergic Crises: What You Need to Know

Reviewed by: HU Medical Review Board | Last reviewed: April 2024 | Last updated: April 2024

If you or a loved one is living with myasthenia gravis (MG), you may worry about complications. One serious complication that can develop is called a myasthenic crisis. Another less common complication is a cholinergic crisis. The symptoms of these crises are similar, but they happen for different reasons.1,2

What causes a myasthenic crisis?

MG is a chronic autoimmune disease caused by the body’s immune system mistakenly attacking the body. This immune system attack interferes with how nerves and muscles interact. This can result in muscle weakness.2,3

A myasthenic crisis happens when muscle weakness affects the muscles related to breathing and swallowing. This causes great difficulty with breathing and swallowing.2,3

What are the symptoms of a myasthenic crisis?

During a myasthenic crisis, the muscles that control breathing and swallowing become extremely weak, often rapidly. This situation can be life-threatening. People in myasthenic crisis may need a machine called a ventilator to help them breathe.2,3

What are the triggers of a myasthenic crisis?

Several things can trigger a myasthenic crisis. However, in some people, there can be no obvious trigger. Possible triggers include:3,4

  • Infection
  • Reaction to medicine
  • Surgery
  • Pregnancy
  • Childbirth
  • Taking a lower dose of immunosuppressive medicines
  • Vaccines

Who can be affected by a myasthenic crisis?

Myasthenic crises occur only in people with MG. About 2 out of every 10 people with MG will experience a myasthenic crisis. A myasthenic crisis is most likely to occur in the first 2 to 3 years of having MG. With proper medical care, more than 95 percent of people will survive a myasthenic crisis.2,3

Some people with MG may be at higher risk for a myasthenic crisis. This includes people who:2,3

  • Have had a previous myasthenic crisis
  • Have severe MG
  • Typically have issues swallowing

What causes a cholinergic crisis?

A cholinergic crisis can happen when there is too much acetylcholine in the body. Acetylcholine is a chemical that can be low in people with MG. Acetylcholine has many roles, including helping muscles move.1,5

MG is often treated with a type of drug called a cholinesterase inhibitor, or acetylcholinesterase inhibitor. These drugs work by stopping a certain type of enzyme from breaking down acetylcholine. This increases the amount of acetylcholine in the body. People who take high doses of cholinesterase inhibitors are more likely to have a cholinergic crisis.1,5

What are the symptoms of a cholinergic crisis?

A cholinergic crisis is much more rare than a myasthenic crisis, but the symptoms can be similar. A cholinergic crisis can also be life-threatening. Someone who is having a cholinergic crisis may experience:1,3,5

  • Trouble breathing
  • Blurry vision or watery eyes
  • Nausea, vomiting, or diarrhea
  • A slower-than-normal heartbeat
  • More saliva than usual
  • A frequent urge to urinate
  • Muscle twitches

Who is at risk for a cholinergic crisis?

A cholinergic crisis can happen whether or not someone has MG. People who may be at higher risk for this type of crisis include:1,5

  • People who received general anesthesia and drugs to reverse the effects of nerve-blocking agents
  • Children and adults who have been exposed to specific chemicals, such as nerve gasses, pesticides, and insecticides
  • People with MG who take very high doses of acetylcholinesterase inhibitors

With proper treatment dosing, most people with MG do not develop this complication. It is extremely rare for someone with MG to have a cholinergic crisis. But because both cholinergic and myasthenic crises can lead to trouble breathing, knowing their symptoms is important. If someone with MG is having trouble breathing, seek medical care as soon as possible.1,4,5

By providing your email address, you are agreeing to our privacy policy.

Join the conversation

Please read our rules before commenting.