autoimmune

Your immune system protects you from disease and infection by attacking germs that get into your body, such as viruses and bacteria. Your immune system can tell that the germs aren't part of you, so it destroys them. If you have an autoimmune disease, your immune system attacks the healthy cells of your organs and tissues by mistake.

There are more than 80 types of autoimmune diseases. They can affect almost any part of your body. For example, alopecia areata is an autoimmune disease of the skin that causes hair loss. Autoimmune hepatitis affects the liver. In type 1 diabetes, the immune system attacks the pancreas. And in rheumatoid arthritis, the immune system can attack many parts of the body, including the joints, lungs, and eyes.

No one is sure why autoimmune diseases happen. But you can't catch them from other people.

Autoimmune diseases do tend to run in families, which means that certain genes may make some people more likely to develop a problem. Viruses, certain chemicals, and other things in the environment may trigger an autoimmune disease if you already have the genes for it.

Millions of Americans of all ages have autoimmune diseases. Women develop many types of autoimmune diseases much more often than men. And if you have one autoimmune disease, you are more likely to get another.

The symptoms of an autoimmune disease depend on the part of your body that's affected. Many types of autoimmune diseases cause redness, swelling, heat, and pain, which are the signs and symptoms of inflammation. But other illnesses can cause the same symptoms.

The symptoms of autoimmune diseases can come and go. During a flare-up, your symptoms may get severe for a while. Later on, you may have a remission, which means that your symptoms get better or disappear for a period of time.

Doctors often have a hard time diagnosing autoimmune diseases. There's usually not a specific test to show whether you have a certain autoimmune disease. And the symptoms can be confusing. That's because many autoimmune diseases have similar symptoms. And some symptoms, such as muscle aches, are common in many other illnesses. So it can take a long time and some visits to different types of doctors to get a diagnosis.

To help your doctor find out if an autoimmune disease is causing your symptoms,:

• Learn about the health conditions in your family history. What health problems did your grandparents, aunts, uncles, and cousins have? Write down what you learn and share it with your doctor.
• Keep track of your symptoms, including how long they last and what makes them better or worse. Share your notes with your doctor.
• See a specialist who deals with the symptoms that bother you most. For example, if you have rash, see a dermatologist (skin doctor).

The treatment depends on the disease. In most cases, the goal of treatment is to suppress (slow down) your immune system, and ease swelling, redness, and pain from inflammation. Your doctor may give you corticosteroids or other medicines to help you feel better. For some diseases, you may need treatment for the rest of your life.

Sjogren's syndrome, also called Sjogren's disease, is a chronic (long-lasting) autoimmune disease. When you have an autoimmune disease, your immune system attacks healthy tissues and organs by mistake. In Sjogren's syndrome, your immune system attacks the glands that make moisture in the eyes, mouth, and other parts of the body. This causes a dry mouth and dry eyes. You may have dryness in other places that need moisture, such as your nose, throat, and skin. Sjogren's can also affect other parts of the body, including your joints, lungs, kidneys, blood vessels, digestive organs, and nerves.

Normally, your immune system protects the body from infection and disease. But with Sjogren's syndrome and other autoimmune diseases, your immune system attacks healthy tissues and organs. Researchers don't know for sure what causes the immune system to do this. But they think that it is caused by a combination of genetic and environmental factors. Studies have linked Sjogren's syndrome to gene changes in several genes. Some researchers also think that the disease may be triggered by something in the environment. For example, they think that one possible trigger could be a previous infection with a virus or bacteria.

Most people with Sjogren's syndrome are women. You can get it at any age, but it is most common in people in their 40s and 50s.

Sjogren's syndrome is more common in people who have other autoimmune diseases such as rheumatoid arthritis and lupus. This is known as a secondary form of Sjogren's syndrome. People who don't have another autoimmune disease have a primary form of Sjogren's syndrome.

Sjogren's syndrome may have different effects on the body. Not everyone will have the same symptoms. Some people have cycles of mild and then severe symptoms.

The two main symptoms are:

• Dry eyes. Your eyes may burn or itch or feel like they have sand in them. Sometimes your vision may be blurry, or you could be bothered by bright lights.
• Dry mouth. Your tongue and your throat may feel dry. You might have trouble swallowing, speaking, and tasting.

Sjogren's syndrome can also affect other parts of the body, causing symptoms such as:

• Joint and muscle pain
• Dry skin
• Rashes on the skin of hands or feet
• Numbness or tingling in the hands or feet
• Vaginal dryness
• Dry cough that doesn't go away
• Fatigue that doesn't go away

There is no single test for Sjogren's syndrome. To find out if you have it, your provider:

• Will ask about your medical history and symptoms.
• Will do a physical exam, which includes checking for signs of dry mouth and signs of related autoimmune diseases.
• May order tests, including:
  • Eye tests to see if you produce a normal amount of tears and to find out if your eyes have been damaged by dryness.
  • Salivary gland tests to measure how much saliva your mouth produces. They could include imaging tests and a biopsy.
  • Blood tests.

There is no cure for Sjogren's syndrome. Treatment focuses on relieving your symptoms. The treatments can be different for each person, depending on which parts of the body are affected. They may include:

• Eye drops (artificial tears) or ointments to relieve dryness in the eyes.
• Saliva substitutes.
• Prescription medicines that cause your salivary glands to make more saliva.
• A minor procedure that places small plugs the tear duct in the corners of the eyes. The plugs block your tears from draining so they stay in your eyes longer.
• Medicines to help with other symptoms caused by Sjogren's syndrome, such as medicines for pain and inflammation.
• Medicines that suppress (weaken) your immune system (for severe cases).

You can also try to relieve some of your symptoms by sucking on sugar-free candy, drinking water often, increasing the humidity in your room, and not smoking. Because having a dry mouth can raise your risk of cavities, it's important to take good care of your teeth and see your dentist regularly.

Hypothyroidism, or underactive thyroid, happens when your thyroid gland doesn't make enough thyroid hormones to meet your body's needs.

Your thyroid is a small, butterfly-shaped gland in the front of your neck. It makes hormones that control the way the body uses energy. These hormones affect nearly every organ in your body and control many of your body's most important functions. For example, they affect your breathing, heart rate, weight, digestion, and moods. Without enough thyroid hormones, many of your body's functions slow down. But there are treatments that can help.

Hypothyroidism has several causes. They include:

• Hashimoto's disease, an autoimmune disorder where your immune system attacks your thyroid. This is the most common cause.
• Thyroiditis, inflammation of the thyroid
• Congenital hypothyroidism, hypothyroidism that is present at birth
• Surgical removal of part or all of the thyroid
• Radiation treatment of the thyroid
• Certain medicines
• In rare cases, a pituitary disease or too much or too little iodine in your diet

You are at higher risk for hypothyroidism if you:

• Are a woman
• Are older than age 60
• Have had a thyroid problem before, such as a goiter
• Have had surgery to correct a thyroid problem
• Have received radiation treatment to the thyroid, neck, or chest
• Have a family history of thyroid disease
• Were pregnant or had a baby in the past 6 months
• Have Turner syndrome, a genetic disorder that affects females
• Have pernicious anemia, in which the body cannot make enough healthy red blood cells because it does not have enough vitamin B12
• Have Sjogren's syndrome, a disease that causes dry eyes and mouth
• Have type 1 diabetes
• Have rheumatoid arthritis, an autoimmune disease that affects the joints
• Have lupus, a chronic autoimmune disease

The symptoms of hypothyroidism can vary from person to person and may include:

• Fatigue
• Weight gain
• A puffy face
• Trouble tolerating cold
• Joint and muscle pain
• Constipation
• Dry skin
• Dry, thinning hair
• Decreased sweating
• Heavy or irregular menstrual periods
• Fertility problems in women
• Depression
• Slowed heart rate
• Goiter, an enlarged thyroid that may cause your neck to look swollen. Sometimes it can cause trouble with breathing or swallowing.

Because hypothyroidism develops slowly, many people don't notice symptoms of the disease for months or even years.

Hypothyroidism can contribute to high cholesterol. In rare cases, untreated hypothyroidism can cause myxedema coma. This is a condition in which your body's functions slow down to the point that it becomes life-threatening.

During pregnancy, hypothyroidism can cause complications, such as premature birth, high blood pressure in pregnancy, and miscarriage. It can also slow the baby's growth and development.

Your health care provider may use many tools to make a diagnosis:

• A medical history, including asking about your symptoms
• A physical exam
• Thyroid tests, such as
  • TSH, T3, T4, and thyroid antibody blood tests
  • Imaging tests, such as a thyroid scan, ultrasound, or radioactive iodine uptake test. A radioactive iodine uptake test measures how much radioactive iodine your thyroid takes up from your blood after you swallow a small amount of it.

The treatment for hypothyroidism is medicine to replace the hormone that your own thyroid can no longer make. About 6 to 8 weeks after you start taking the medicine, you will get a blood test to check your thyroid hormone level. Your health care provider will adjust your dose if needed. Each time your dose is adjusted, you'll have another blood test. Once you find the right dose, you will probably get a blood test in 6 months. After that, you will need the test once a year.

If you take your medicine according to the instructions, you usually should be able to control the hypothyroidism. You should never stop taking your medicine without talking with your health care provider first.

If you have Hashimoto's disease or other types of autoimmune thyroid disorders, you may be sensitive to harmful side effects from iodine. Talk to your health care provider about which foods, supplements, and medicines you need to avoid.

Women need more iodine when they are pregnant because the baby gets iodine from the mother's diet. If you are pregnant, talk with your health care provider about how much iodine you need.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

Hepatitis is inflammation of the liver. Inflammation is swelling that happens when tissues of the body are injured or infected. It can damage your liver. This swelling and damage can affect how well your liver functions.

Hepatitis can be an acute (short-term) infection or a chronic (long-term) infection. Some types of hepatitis cause only acute infections. Other types can cause both acute and chronic infections.

There are different types of hepatitis, with different causes:

• Viral hepatitis is the most common type. It is caused by one of several viruses -- hepatitis viruses A, B, C, D, and E. In the United States, A, B, and C are the most common.
• Alcoholic hepatitis is caused by heavy alcohol use
• Toxic hepatitis can be caused by certain poisons, chemicals, medicines, or supplements
• Autoimmune hepatitis is a chronic type in which your body's immune system attacks your liver. The cause is not known, but genetics and your environment may play a role.

Hepatitis A and hepatitis E usually spread through contact with food or water that was contaminated with an infected person's stool. You can also get hepatitis E by eating undercooked pork, deer, or shellfish.

Hepatitis B, hepatitis C, and hepatitis D spread through contact with the blood of someone who has the disease. Hepatitis B and D may also spread through contact with other body fluids. This can happen in many ways, such as sharing drug needles or having unprotected sex.

The risks are different for the different types of hepatitis. For example, with most of the viral types, your risk is higher if you have unprotected sex. People who drink a lot over long periods of time are at risk for alcoholic hepatitis.

Some people with hepatitis do not have symptoms and do not know they are infected. If you do have symptoms, they may include:

• Fever
• Fatigue
• Loss of appetite
• Nausea and/or vomiting
• Abdominal pain
• Dark urine
• Clay-colored bowel movements
• Joint pain
• Jaundice, yellowing of your skin and eyes

If you have an acute infection, your symptoms can start anywhere between 2 weeks to 6 months after you got infected. If you have a chronic infection, you may not have symptoms until many years later.

Chronic hepatitis can lead to complications such as cirrhosis (scarring of the liver), liver failure, and liver cancer. Early diagnosis and treatment of chronic hepatitis may prevent these complications.

To diagnose hepatitis, your health care provider:

• Will ask about your symptoms and medical history
• Will do a physical exam
• Will likely do blood tests, including tests for viral hepatitis
• Might do imaging tests, such as an ultrasound, CT scan, or MRI
• May need to do a liver biopsy to get a clear diagnosis and check for liver damage

Treatment for hepatitis depends on which type you have and whether it is acute or chronic. Acute viral hepatitis often goes away on its own. To feel better, you may just need to rest and get enough fluids. But in some cases, it may be more serious. You might even need treatment in a hospital.

There are different medicines to treat the different chronic types of hepatitis. Possible other treatments may include surgery and other medical procedures. People who have alcoholic hepatitis need to stop drinking. If your chronic hepatitis leads to liver failure or liver cancer, you may need a liver transplant.

There are different ways to prevent or lower your risk for hepatitis, depending on the type of hepatitis. For example, not drinking too much alcohol can prevent alcoholic hepatitis. There are vaccines to prevent hepatitis A and B. Autoimmune hepatitis cannot be prevented.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

Crohn's disease is a chronic (long-lasting) disease that causes inflammation in your digestive tract. It can affect any part of your digestive tract, which runs from your mouth to your anus. But it usually affects your small intestine and the beginning of your large intestine.

Crohn's disease is an inflammatory bowel disease (IBD). Ulcerative colitis and microscopic colitis are other common types of IBD.

The cause of Crohn's disease is unknown. Researchers think that an autoimmune reaction may be one cause. An autoimmune reaction happens when your immune system attacks healthy cells in your body. Genetics may also play a role, since Crohn's disease can run in families.

Stress and eating certain foods don't cause the disease, but they can make your symptoms worse.

There are certain factors that may raise your risk of Crohn's disease:

• Family history of the disease. Having a parent, child, or sibling with the disease puts you at higher risk.
• Smoking. This may double your risk of developing Crohn's disease.
• Certain medicines, such as antibiotics, birth-control pills, and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen. These may slightly increase your chance of developing Crohn's.
• A high-fat diet. This may also slightly increase your risk of Crohn's.

The symptoms of Crohn's disease can vary, depending where and how severe your inflammation is. The most common symptoms include:

• Diarrhea
• Cramping and pain in your abdomen
• Weight loss

Some other possible symptoms are:

• Anemia, a condition in which you have fewer red blood cells than normal
• Eye redness or pain
• Fatigue
• Fever
• Joint pain or soreness
• Nausea or loss of appetite
• Skin changes that involve red, tender bumps under the skin

Stress and eating certain foods such as carbonated (fizzy) drinks and high-fiber foods may make some people's symptoms worse.

Crohn's disease can cause other problems, including:

• Intestinal obstruction, a blockage in the intestine
• Fistulas, abnormal connections between two parts inside of the body
• Abscesses, pus-filled pockets of infection
• Anal fissures, small tears in your anus that may cause itching, pain, or bleeding
• Ulcers, open sores in your mouth, intestines, anus, or perineum
• Malnutrition, when your body does not get the right amount of vitamins, minerals, and nutrients it needs
• Inflammation in other areas of your body, such as your joints, eyes, and skin

Your health care provider may use many tools to make a diagnosis:

• A medical history, which includes asking about your symptoms
• A family history
• A physical exam, including:
  • Checking for bloating in your abdomen.
  • Listening to sounds within your abdomen using a stethoscope.
  • Tapping on your abdomen to check for tenderness and pain and to see if your liver or spleen is abnormal or enlarged.
• Various tests, including:
  • Blood and stool tests.
  • A colonoscopy.
  • An upper GI endoscopy, a procedure in which your provider uses a scope to look inside your mouth, esophagus, stomach, and small intestine.
  • Diagnostic imaging tests, such as a CT scan or an upper GI series. An upper GI series uses a special liquid called barium and x-rays. Drinking the barium will make your upper GI tract more visible on an x-ray.

There is no cure for Crohn's disease, but treatments can decrease inflammation in your intestines, relieve symptoms, and prevent complications. Treatments include medicines, bowel rest, and surgery. No single treatment works for everyone. You and your provider can work together to figure out which treatment is best for you:

• Medicines for Crohn's include various medicines that decrease the inflammation. Many of these medicines do this by reducing the activity of your immune system. Certain medicines can also help with symptoms or complications, such as nonsteroidal anti-inflammatory drugs and anti-diarrheal medicines. If your Crohn's causes an infection, you may need antibiotics.
• Bowel rest involves drinking only certain liquids or not eating or drinking anything. This allows your intestines to rest. You may need to do this if your Crohn's disease symptoms are severe. You get your nutrients through drinking a liquid, a feeding tube, or an intravenous (IV) tube. You may need to do bowel rest in the hospital, or you may be able to do it at home. It will last for a few days or up to several weeks.
• Surgery can treat complications and reduce symptoms when other treatments are not helping enough. The surgery will involve removing a damaged part of your digestive tract to treat:
  • Fistulas
  • Bleeding that is life threatening
  • Intestinal obstructions
  • Side effects from medicines when they threaten your health
  • Symptoms when medicines do not improve your condition

Changing your diet can help reduce symptoms. Your provider may recommend that you make changes to your diet, such as:

• Avoiding carbonated drinks
• Avoiding popcorn, vegetable skins, nuts, and other high-fiber foods
• Drinking more liquids
• Eating smaller meals more often
• Keeping a food diary to help identify foods that cause problems

In some cases, your provider may ask you to go on a special diet, such as a diet that is:

• High calorie
• Lactose free
• Low fat
• Low fiber
• Low salt

If you are not absorbing enough nutrients, you may need to take nutritional supplements and vitamins.

National Institute of Diabetes and Digestive and Kidney Diseases

Your immune system is a complex network of cells, tissues, and organs. Together they help the body fight infections and other diseases.

When germs such as bacteria or viruses invade your body, they attack and multiply. This is called an infection. The infection causes the disease that makes you sick. Your immune system protects you from the disease by fighting off the germs.

The immune system has many different parts, including:

• Your skin, which can help prevent germs from getting into the body
• Mucous membranes, which are the moist, inner linings of some organs and body cavities. They make mucus and other substances which can trap and fight germs.
• White blood cells, which fight germs
• Organs and tissues of the lymph system, such as the thymus, spleen, tonsils, lymph nodes, lymph vessels, and bone marrow. They produce, store, and carry white blood cells.

Your immune system defends your body against substances it sees as harmful or foreign. These substances are called antigens. They may be germs such as bacteria and viruses. They might be chemicals or toxins. They could also be cells that are damaged from things like cancer or sunburn.

When your immune system recognizes an antigen, it attacks it. This is called an immune response. Part of this response is to make antibodies. Antibodies are proteins that work to attack, weaken, and destroy antigens. Your body also makes other cells to fight the antigen.

Afterwards, your immune system remembers the antigen. If it sees the antigen again, it can recognize it. It will quickly send out the right antibodies, so in most cases, you don't get sick. This protection against a certain disease is called immunity.

There are three different types of immunity:

• Innate immunity is the protection that you are born with. It is your body's first line of defense. It includes barriers such as the skin and mucous membranes. They keep harmful substances from entering the body. It also includes some cells and chemicals which can attack foreign substances.
• Active immunity, also called adaptive immunity, develops when you are infected with or vaccinated against a foreign substance. Active immunity is usually long-lasting. For many diseases, it can last your entire life.
• Passive immunity happens when you receive antibodies to a disease instead of making them through your own immune system. For example, newborn babies have antibodies from their mothers. People can also get passive immunity through blood products that contain antibodies. This kind of immunity gives you protection right away. But it only lasts a few weeks or months.

Sometimes a person may have an immune response even though there is no real threat. This can lead to problems such as allergies, asthma, and autoimmune diseases. If you have an autoimmune disease, your immune system attacks healthy cells in your body by mistake.

Other immune system problems happen when your immune system does not work correctly. These problems include immunodeficiency diseases. If you have an immunodeficiency disease, you get sick more often. Your infections may last longer and can be more serious and harder to treat. They are often genetic disorders.

There are other diseases that can affect your immune system. For example, HIV is a virus that harms your immune system by destroying your white blood cells. If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome). People with AIDS have badly damaged immune systems. They get an increasing number of severe illnesses.

Your joints are places where two or more bones come together. Your shoulders, elbows, hips, knees, and knuckles are all joints. Your spine has joints, too.

But joints are more than bones. They include the soft tissues around them, such as cartilage, tendons and ligaments. Cartilage is the hard slippery flexible tissue that covers the ends of your bones at a joint. Tendons are tough, flexible bands that connect your muscles to your bones so you can move your joints. Ligaments connect the bones of the joint to each other to keep them stable when you move.

Joint disorders are diseases or injuries that affect your joints. Injuries can happen because of overuse of a joint. Or you could have a sudden injury, such as an accident or a sports injury.

Many diseases can affect the joints. They often cause joint pain and make your joints stiff, red, or swollen. Most of them are chronic. That means they last a long time. Some may never go away completely. Some of the diseases that affect the joints include:

• Arthritis. Arthritis may cause joint pain and swelling. There are many types of this disease. Osteoarthritis is the most common type. Over time, arthritis can cause severe joint damage. It can affect people of all ages. A joint injury when you're young may cause osteoarthritis later in life.
• Lupus. This autoimmune disease affects many parts of the body and can cause joint and muscle pain. Some types of lupus often cause arthritis.
• Sjögren's Syndrome. This autoimmune disease affects glands that make moisture in many parts of the body. The main symptoms are dry eyes and mouth, but it often causes joint pain, too.

Treatments are different depending on the disease. But most treatments include medicines and therapies to relieve pain and other symptoms.

Joint disorders from sudden injuries include:

• Sprains and strains. Sprains are stretched or torn ligaments. Acute strains are stretched or torn muscles or tendons that happen from a sudden injury or movement, such as lifting a heavy object.
• Dislocated joints. A joint is dislocated when the bones are pushed or pulled out of position. A joint dislocation is a medical emergency.

Treatment depends on the type of injury. You can treat many sports injuries at home. But you should call your health care provider if you:

• Have a lot of joint pain, swelling or numbness
• Can't put weight on the joint
• Have pain from an old injury with more swelling, an unstable joint, or a joint that isn't normal in another way

Overuse injuries usually damage the soft tissues of the joint. They can happen when you work a joint too hard by doing the same movements over and over. For example, you could get an overuse injury from playing a musical instrument, playing sports, or doing certain jobs, such as carpentry or painting.

Joint overuse injuries include:

• Bursitis. The bursa is a small fluid-filled sac. It works as a pad between the bones of a joint and the moving parts around it, such as muscles, tendons and skin. With bursitis, the bursa becomes irritated and swollen with extra fluid. Overuse is the most common cause, but injuries, infections and other conditions, such as arthritis, can cause bursitis.
• Tendinitis. This condition happens when you overuse a tendon. It swells and makes the joint painful to move.
• Chronic strain. A strain becomes chronic when your muscles or tendons stretch or tear slowly over time from repeating the same movements.

The treatments for bursitis, tendinitis, and chronic strain are often the same. They usually include rest, keeping the injured joint higher than your heart, and taking medicine to reduce swelling. Your provider may recommend gentle exercise and other treatment. In some cases, your provider may suggest an injection (a shot) of medicine into the joint. If these do not help, you may need surgery.

Getting enough physical activity is one of the most important things you can do to prevent or slow joint disorders. Activity strengthens the muscles around your joints and helps them work better.

When you play sports, wear the right equipment to protect your joints, such as knee pads. If you already have joint problems, ask your provider what type of activities are best for you.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

The lymphatic system is a network of tissues and organs. It is made up of:

• Lymph - a fluid that contains white blood cells that defend against germs
• Lymph vessels - vessels that carry lymph throughout your body. They are different from blood vessels.
• Lymph nodes - glands found throughout the lymph vessels. Along with your spleen, these nodes are where white blood cells fight infection.

Your bone marrow and thymus produce the cells in lymph. They are part of the system, too.

The lymphatic system clears away infection and keeps your body fluids in balance. If it's not working properly, fluid builds in your tissues and causes swelling, called lymphedema. Other lymphatic system problems can include infections, blockage, and cancer.

Multiple sclerosis (MS) is a nervous system disease that affects your brain and spinal cord. It damages the myelin sheath, the material that surrounds and protects your nerve cells. This damage slows down or blocks messages between your brain and your body, leading to the symptoms of MS. They can include:

• Visual disturbances
• Muscle weakness
• Trouble with coordination and balance
• Sensations such as numbness, prickling, or "pins and needles"
• Thinking and memory problems

No one knows what causes MS. It may be an autoimmune disease, which happens when your immune system attacks healthy cells in your body by mistake. Multiple sclerosis affects women more than men. It often begins between the ages of 20 and 40. Usually, the disease is mild, but some people lose the ability to write, speak, or walk.

There is no specific test for MS. Doctors use a medical history, physical exam, neurological exam, MRI, and other tests to diagnose it. There is no cure for MS, but medicines may slow it down and help control symptoms. Physical and occupational therapy may also help.

NIH: National Institute of Neurological Disorders and Stroke

Myasthenia gravis, sometimes called MG, is a chronic (long-lasting) disease that causes weakness in your voluntary muscles. The voluntary muscles are the ones that you can control. They include the muscles you use for:

• Eye and eyelid movement
• Facial expressions
• Chewing
• Talking
• Swallowing
• Breathing
• Moving your arms and legs

You can also have weakness in other muscles. This weakness gets worse with activity, and better with rest.

Myasthenia gravis is a type of autoimmune disease. In autoimmune diseases, your immune system attacks the healthy cells of your organs and tissues by mistake.

Myasthenia gravis is caused by an error in how nerve signals are sent to muscles. These signals get blocked at the nerve-muscle junction. This junction is the place where the nerve endings connect with the muscles they control.

Normally, this is how the signals work:

• The signals travel down a nerve that controls movement in the muscle
• The nerve endings release a substance called acetylcholine
• Acetylcholine binds to the muscle tissue at the nerve-muscle junction
• This causes the muscle to contract (move)

But in someone with myasthenia gravis, the body's own immune system makes antibodies that block the binding of acetylcholine to the muscle. This makes the muscles weaker.

The thymus gland, which is part of your immune system, may play a role in myasthenia gravis. Normally, your thymus gland is active and growing when you are a child. It makes white blood cells to fight infections. At puberty, it starts getting smaller and is replaced by fat. It is usually small by the time you are an adult. But in many adults with myasthenia gravis, the thymus gland stays large. And some people with myasthenia gravis can get thymomas, which are tumors of the thymus. The are usually benign (not cancer), but they can sometimes become cancerous.

Although myasthenia gravis can affect people of any age, it is most common in young adult women (under age 40) and older men (over age 60). It is usually not inherited (passed down in families).

Myasthenia gravis normally does not affect infants. But it's possible for pregnant people who have myasthenia gravis to pass the antibodies to their unborn babies. The baby can then be born with neonatal myasthenia. This condition is usually temporary, and the symptoms typically go away within two to three months after birth.

The symptoms of myasthenia gravis will depend on which muscles are affected. The symptoms often include:

• Weakness of the eye muscles
• Drooping of one or both eyelids
• Blurred or double vision
• Changes in facial expressions
• Trouble swallowing
• Shortness of breath
• Speech problems
• Weakness in the arms, hands, fingers, legs, and neck

Different people have different levels of muscle weakness. And the weakness can vary from day to day. Some days it might be mild, and other days it might be worse. Physical activity often makes the muscle weakness worse.

Some people with myasthenia gravis can get severe weakness that affects the muscles that control breathing. This is called a myasthenic crisis, and it is a life-threatening emergency.

There are many other conditions that can cause muscle weakness, so myasthenia gravis can be hard to diagnose. To find out if you have myasthenia gravis, your health care provider:

• Will ask about your medical history and symptoms
• Will do a physical exam, including a neurological exam
• Will likely order tests for myasthenia gravis, including:
  • Blood tests
  • Imaging tests
  • Electromyography (EMG) and nerve conduction studies

There is no cure for myasthenia gravis, but treatments that can improve muscle weakness and help with symptoms. They include:

• Anticholinesterase medicines, which can improve nerve-to-muscle messages and make muscles stronger.
• Immunosuppressive medicines, which are medicines that decrease your body's immune system responses. They can lower your body's production of abnormal antibodies.
• Monoclonal antibodies, which can also help decrease your body's immune system responses.
• Plasmapheresis (plasma exchange) and intravenous immunoglobulin, which are procedures to remove abnormal antibodies from your blood. They are usually used in severe cases. They can help with symptoms for a few weeks or months.
• Thymectomy, surgery to remove the thymus gland. It can reduce the symptoms of myasthenia gravis, possibly by rebalancing the immune system.

Lifestyle changes may be helpful for some people. The changes could include regular gentle exercise, getting enough rest, and eating healthy foods.

Some people with myasthenia gravis go into remission. This means that they do not have symptoms. The remission is usually temporary, but sometimes it can be permanent.

NIH: National Institute of Neurological Disorders and Stroke