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What is meningococcal disease? Meningococcal disease is the name for any illness that is caused by Neisseria meningitidis bacteria (also called meningococcal ...
What is menopause? Menopause is the time in your life when you stop having your period and can no longer get pregnant. You have reached menopause when ...
What is menstruation? Menstruation, also called a period, is normal vaginal bleeding that happens as part of the monthly cycle in women and girls. Every ...
What are mental disorders? Mental disorders (or mental illnesses) are conditions that affect your thinking, feeling, mood, and behavior. They may happen ...
What is mental health? Mental health includes our emotional, psychological, and social well-being. It affects how we think, feel, and act as we cope with ...
What is metabolic syndrome? Metabolic syndrome is the name for a group of risk factors for heart disease, diabetes, and other health problems. You can ...
What are migraines? Migraines are a recurring type of headache. They cause moderate to severe pain that is throbbing or pulsing. The pain is often on ...
What is a miscarriage? A miscarriage is an unexpected loss of pregnancy before the 20th week. Most miscarriages happen very early in the pregnancy, often ...
What is the mitral valve? The mitral valve is one of the four valves in your heart. Heart valves have flaps that open and close. The flaps make sure that ...
What are mobility aids? Mobility aids help you walk or move from place to place if you have a disability or an injury. Types of mobility aids can include: ...
Mosquitoes are insects that live all over the world. There are thousands of different species of mosquitoes; about 200 of those live in the United States. Female ...
What is mpox? Mpox, which used to be called monkeypox, is a disease caused by the monkeypox virus. This virus is in the same family of viruses as the ...
What is an MRI scan? Magnetic resonance imaging (MRI) is an imaging test that is usually painless and uses magnets, radio waves, and a computer to create ...
What is multiple sclerosis? Multiple sclerosis (MS) is a disease that affects your brain and spinal cord, also called the central nervous system. MS damages ...
What are muscle cramps? Muscle cramps are sudden, involuntary contractions or spasms in one or more of your muscles. They are very common and often occur ...
What is muscular dystrophy (MD)? Muscular dystrophy (MD) is a group of more than 30 genetic diseases. They cause weakness of the muscles. Over time, the ...
What is myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)? Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a serious, long-term ...
What is myasthenia gravis? Myasthenia gravis, sometimes called MG, is a chronic (long-lasting) disease that causes weakness in your voluntary muscles. ...
What is neuroblastoma? Neuroblastoma is a type of cancer that forms in nerve cells called neuroblasts. Neuroblasts are immature nerve tissue. They normally ...
What is pain? Pain is a signal in your nervous system that something may be wrong. It is an unpleasant feeling, such as a prick, tingle, sting, burn, ...
