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Pernicious anemia (per-NISH-us uh-NEE-me-uh) is a condition in which the body can't make enough healthy red blood cells because it doesn't have enough vitamin B12.
                
Vitamin B12 is a nutrient found in some foods. The body needs this nutrient to make healthy red blood cells and to keep its nervous system working properly.
                
People who have pernicious anemia can't absorb enough vitamin B12 from food. This is because they lack intrinsic (in-TRIN-sik) factor, a protein made in the stomach. A lack of this protein leads to vitamin B12 deficiency.
                
Other conditions and factors also can cause vitamin B12 deficiency. Examples include infections, surgery, medicines, and diet. Technically, the term "pernicious anemia" refers to vitamin B12 deficiency due to a lack of intrinsic factor. Often though, vitamin B12 deficiency due to other causes also is called pernicious anemia.
                
This article discusses pernicious anemia due to a lack of intrinsic factor and other causes.
                
Overview
                
Pernicious anemia is a type of anemia. The term "anemia" usually refers to a condition in which the blood has a lower than normal number of red blood cells. In pernicious anemia, the body can't make enough healthy red blood cells because it doesn't have enough vitamin B12.
                
Without enough vitamin B12, your red blood cells don't divide normally and are too large. They may have trouble getting out of the bone marrowa sponge-like tissue inside the bones where blood cells are made.
                
Without enough red blood cells to carry oxygen to your body, you may feel tired and weak. Severe or long-lasting pernicious anemia can damage the heart, brain, and other organs in the body.
                
Pernicious anemia also can cause other problems, such as nerve damage, neurological problems (such as memory loss), and digestive tract problems. People who have pernicious anemia also may be at higher risk for weakened bone strength and stomach cancer.
                
Outlook
                
The term pernicious means deadly. The condition is called pernicious anemia because it often was fatal in the past, before vitamin B12 treatments were available. Now, pernicious anemia usually is easy to treat with vitamin B12 pills or shots.
                
With ongoing care and proper treatment, most people who have pernicious anemia can recover, feel well, and live normal lives.
                
Without treatment, pernicious anemia can lead to serious problems with the heart, nerves, and other parts of the body. Some of these problems may be permanent.
Pernicious anemia is more common in people of Northern European and African descent than in other ethnic groups.
                
Older people also are at higher risk for the condition. This is mainly due to a lack of stomach acid and intrinsic factor, which prevents the small intestine from absorbing vitamin B12. As people grow older, they tend to make less stomach acid.
                
Pernicious anemia also can occur in younger people and other populations. You're at higher risk for pernicious anemia if you:
                
Have a family history of the condition.
                
Have had part or all of your stomach surgically removed. The stomach makes intrinsic factor. This protein helps your body absorb vitamin B12.
                
Have an autoimmune disorder that involves the endocrine glands, such as Addison's disease, type 1 diabetes, Graves' disease, or vitiligo. Research suggests a link may exist between these autoimmune disorders and pernicious anemia that's caused by an autoimmune response.
                
Have had part or all of your small intestine surgically removed. The small intestine is where vitamin B12 is absorbed.
                
Have certain intestinal diseases or other disorders that may prevent your body from properly absorbing vitamin B12. Examples include Crohn's disease, intestinal infections, and HIV.
                
Take medicines that prevent your body from properly absorbing vitamin B12. Examples of such medicines include antibiotics and certain seizure medicines.
                
Are a strict vegetarian who doesn't eat any animal or dairy products and doesn't take a vitamin B12 supplement, or if you eat poorly overall.
A lack of vitamin B12 (vitamin B12 deficiency) causes the signs and symptoms of pernicious anemia. Without enough vitamin B12, your body can't make enough healthy red blood cells, which causes anemia.
                
Some of the signs and symptoms of pernicious anemia apply to all types of anemia. Other signs and symptoms are specific to a lack of vitamin B12.
                
Signs and Symptoms of Anemia
                
The most common symptom of all types of anemia is fatigue (tiredness). Fatigue occurs because your body doesnt have enough red blood cells to carry oxygen to its various parts.
                
A low red blood cell count also can cause shortness of breath, dizziness, headache, coldness in your hands and feet, pale or yellowish skin, and chest pain.
                
A lack of red blood cells also means that your heart has to work harder to move oxygen-rich blood through your body. This can lead to irregular heartbeats called arrhythmias (ah-RITH-me-ahs), heart murmur, an enlarged heart, or even heart failure.
                
Signs and Symptoms of Vitamin B12 Deficiency
                
Vitamin B12 deficiency may lead to nerve damage. This can cause tingling and numbness in your hands and feet, muscle weakness, and loss of reflexes. You also may feel unsteady, lose your balance, and have trouble walking. Vitamin B12 deficiency can cause weakened bones and may lead to hip fractures.
                
Severe vitamin B12 deficiency can cause neurological problems, such as confusion, dementia, depression, and memory loss.
                
Other symptoms of vitamin B12 deficiency involve the digestive tract. These symptoms include nausea (feeling sick to your stomach) and vomiting, heartburn, abdominal bloating and gas, constipation or diarrhea, loss of appetite, and weight loss. An enlarged liver is another symptom.
                
A smooth, thick, red tongue also is a sign of vitamin B12 deficiency and pernicious anemia.
                
Infants who have vitamin B12 deficiency may have poor reflexes or unusual movements, such as face tremors. They may have trouble feeding due to tongue and throat problems. They also may be irritable. If vitamin B12 deficiency isn't treated, these infants may have permanent growth problems.
Doctors treat pernicious anemia by replacing the missing vitamin B12 in the body. People who have pernicious anemia may need lifelong treatment.
                
The goals of treating pernicious anemia include:
                
Preventing or treating the anemia and its signs and symptoms
                
Preventing or managing complications, such as heart and nerve damage
                
Treating the cause of the pernicious anemia (if a cause can be found)
                
Specific Types of Treatment
                
Pernicious anemia usually is easy to treat with vitamin B12 shots or pills.
                
If you have severe pernicious anemia, your doctor may recommend shots first. Shots usually are given in a muscle every day or every week until the level of vitamin B12 in your blood increases. After your vitamin B12 blood level returns to normal, you may get a shot only once a month.
                
For less severe pernicious anemia, your doctor may recommend large doses of vitamin B12 pills. A vitamin B12 nose gel and spray also are available. These products may be useful for people who have trouble swallowing pills, such as older people who have had strokes.
                
Your signs and symptoms may begin to improve within a few days after you start treatment. Your doctor may advise you to limit your physical activity until your condition improves.
                
If your pernicious anemia is caused by something other than a lack of intrinsic factor, you may get treatment for the cause (if a cause can be found). For example, your doctor may prescribe medicines to treat a condition that prevents your body from absorbing vitamin B12.
                
If medicines are the cause of your pernicious anemia, your doctor may change the type or dose of medicine you take. Infants of strict vegetarian mothers may be given vitamin B12 supplements from birth.
You can't prevent pernicious anemia caused by a lack of intrinsic factor. Without intrinsic factor, you won't be able to absorb vitamin B12 and will develop pernicious anemia.
                
Although uncommon, some people develop pernicious anemia because they don't get enough vitamin B12 in their diets. You can take steps to prevent pernicious anemia caused by dietary factors.
                
Eating foods high in vitamin B12 can help prevent low vitamin B12 levels. Good food sources of vitamin B12 include:
                
Breakfast cereals with added vitamin B12
                
Meats such as beef, liver, poultry, and fish
                
Eggs and dairy products (such as milk, yogurt, and cheese)
                
Foods fortified with vitamin B12, such as soy-based beverages and vegetarian burgers
                
If youre a strict vegetarian, talk with your doctor about having your vitamin B12 level checked regularly.
                
Vitamin B12 also is found in multivitamins and B-complex vitamin supplements. Doctors may recommend supplements for people at risk for vitamin B12 deficiency, such as strict vegetarians or people who have had stomach surgery.
                
Older adults may have trouble absorbing vitamin B12. Thus, doctors may recommend that older adults eat foods fortified with vitamin B12 or take vitamin B12 supplements.
When you're awake, throat muscles help keep your airway stiff and open so air can flow into your lungs. When you sleep, these muscles relax, which narrows your throat.
                
Normally, this narrowing doesnt prevent air from flowing into and out of your lungs. But if you have sleep apnea, your airway can become partially or fully blocked because:
                
Your throat muscles and tongue relax more than normal.
                
Your tongue and tonsils (tissue masses in the back of your mouth) are large compared with the opening into your windpipe.
                
You're overweight. The extra soft fat tissue can thicken the wall of the windpipe. This narrows the inside of the windpipe, which makes it harder to keep open.
                
The shape of your head and neck (bony structure) may cause a smaller airway size in the mouth and throat area.
                
The aging process limits your brain signals' ability to keep your throat muscles stiff during sleep. Thus, your airway is more likely to narrow or collapse.
                
Not enough air flows into your lungs if your airway is partially or fully blocked during sleep. As a result, loud snoring and a drop in your blood oxygen level can occur.
                
If the oxygen drops to a dangerous level, it triggers your brain to disturb your sleep. This helps tighten the upper airway muscles and open your windpipe. Normal breathing then starts again, often with a loud snort or choking sound.
                
Frequent drops in your blood oxygen level and reduced sleep quality can trigger the release of stress hormones. These hormones raise your heart rate and increase your risk for high blood pressure, heart attack, stroke, and arrhythmias (irregular heartbeats). The hormones also can raise your risk for, or worsen, heart failure.
                
Untreated sleep apnea also can lead to changes in how your body uses energy. These changes increase your risk for obesity and diabetes.
Obstructive sleep apnea is a common condition. About half of the people who have this condition are overweight.
                
Men are more likely than women to have sleep apnea. Although the condition can occur at any age, the risk increases as you get older. A family history of sleep apnea also increases your risk for the condition.
                
People who have small airways in their noses, throats, or mouths are more likely to have sleep apnea. Small airways might be due to the shape of these structures or allergies or other conditions that cause congestion.
                
Small children might have enlarged tonsil tissues in their throats. Enlarged tonsil tissues raise a childs risk for sleep apnea. Overweight children also might be at increased risk for sleep apnea.
                
About half of the people who have sleep apnea also have high blood pressure. Sleep apnea also is linked to smoking, metabolic syndrome, diabetes, and risk factors for stroke and heart failure.
                
Race and ethnicity might play a role in the risk of developing sleep apnea. However, more research is needed.
Major Signs and Symptoms
                
One of the most common signs of obstructive sleep apnea is loud and chronic (ongoing) snoring. Pauses may occur in the snoring. Choking or gasping may follow the pauses.
                
The snoring usually is loudest when you sleep on your back; it might be less noisy when you turn on your side. You might not snore every night. Over time, however, the snoring can happen more often and get louder.
                
You're asleep when the snoring or gasping happens. You likely won't know that you're having problems breathing or be able to judge how severe the problem is. A family member or bed partner often will notice these problems before you do.
                
Not everyone who snores has sleep apnea.
                
Another common sign of sleep apnea is fighting sleepiness during the day, at work, or while driving. You may find yourself rapidly falling asleep during the quiet moments of the day when you're not active. Even if you don't have daytime sleepiness, talk with your doctor if you have problems breathing during sleep.
                
Other Signs and Symptoms
                
Others signs and symptoms of sleep apnea include:
                
Morning headaches
                
Memory or learning problems and not being able to concentrate
                
Feeling irritable, depressed, or having mood swings or personality changes
                
Waking up frequently to urinate
                
Dry mouth or sore throat when you wake up
                
In children, sleep apnea can cause hyperactivity, poor school performance, and angry or hostile behavior. Children who have sleep apnea also may breathe through their mouths instead of their noses during the day.
Sleep deficiency, which includes sleep deprivation, affects people of all ages, races, and ethnicities. Certain groups of people may be more likely to be sleep deficient. Examples include people who:
                
Have limited time available for sleep, such as caregivers or people working long hours or more than one job
                
Have schedules that conflict with their internal body clocks, such as shift workers, first responders, teens who have early school schedules, or people who must travel for work
                
Make lifestyle choices that prevent them from getting enough sleep, such as taking medicine to stay awake, abusing alcohol or drugs, or not leaving enough time for sleep
                
Have undiagnosed or untreated medical problems, such as stress, anxiety, or sleep disorders
                
Have medical conditions or take medicines that interfere with sleep
                
Certain medical conditions have been linked to sleep disorders. These conditions include heart failure, heart disease, obesity, diabetes, high blood pressure, stroke or transient ischemic attack (mini-stroke), depression, and attention-deficit hyperactivity disorder (ADHD).
                
If you have or have had one of these conditions, ask your doctor whether you might benefit from a sleep study.
                
A sleep study allows your doctor to measure how much and how well you sleep. It also helps show whether you have sleep problems and how severe they are. For more information, go to the Health Topics Sleep Studies article.
                
If you have a child who is overweight, talk with the doctor about your child's sleep habits.
Sleep deficiency can cause you to feel very tired during the day. You may not feel refreshed and alert when you wake up. Sleep deficiency also can interfere with work, school, driving, and social functioning.
                
How sleepy you feel during the day can help you figure out whether you're having symptoms of problem sleepiness. You might be sleep deficient if you often feel like you could doze off while:
                
Sitting and reading or watching TV
                
Sitting still in a public place, such as a movie theater, meeting, or classroom
                
Riding in a car for an hour without stopping
                
Sitting and talking to someone
                
Sitting quietly after lunch
                
Sitting in traffic for a few minutes
                
Sleep deficiency can cause problems with learning, focusing, and reacting. You may have trouble making decisions, solving problems, remembering things, controlling your emotions and behavior, and coping with change. You may take longer to finish tasks, have a slower reaction time, and make more mistakes.
                
The signs and symptoms of sleep deficiency may differ between children and adults. Children who are sleep deficient might be overly active and have problems paying attention. They also might misbehave, and their school performance can suffer.
                
Sleep-deficient children may feel angry and impulsive, have mood swings, feel sad or depressed, or lack motivation.
                
You may not notice how sleep deficiency affects your daily routine. A common myth is that people can learn to get by on little sleep with no negative effects. However, research shows that getting enough quality sleep at the right times is vital for mental health, physical health, quality of life, and safety.
                
To find out whether you're sleep deficient, try keeping a sleep diary for a couple of weeks. Write down how much you sleep each night, how alert and rested you feel in the morning, and how sleepy you feel during the day.
                
Compare the amount of time you sleep each day with the average amount of sleep recommended for your age group, as shown in the chart in "How Much Sleep Is Enough?" If you often feel very sleepy, and efforts to increase your sleep don't help, talk with your doctor.
                
You can find a sample sleep diary in the National Heart, Lung, and Blood Institute's "Your Guide to Healthy Sleep."
An electrocardiogram (e-lek-tro-KAR-de-o-gram), also called an EKG or ECG, is a simple, painless test that records the heart's electrical activity. To understand this test, it helps to understand how the heart works.
                
With each heartbeat, an electrical signal spreads from the top of the heart to the bottom. As it travels, the signal causes the heart to contract and pump blood. The process repeats with each new heartbeat.
                
The heart's electrical signals set the rhythm of the heartbeat. For more detailed information and animations, go to the Health Topics How the Heart Works article.
                
An EKG shows:
                
How fast your heart is beating
                
Whether the rhythm of your heartbeat is steady or irregular
                
The strength and timing of electrical signals as they pass through each part of your heart
                
Doctors use EKGs to detect and study many heart problems, such as heart attacks, arrhythmias (ah-RITH-me-ahs), and heart failure. The test's results also can suggest other disorders that affect heart function.
An electrocardiogram (EKG) is painless and harmless. A nurse or technician will attach soft, sticky patches called electrodes to the skin of your chest, arms, and legs. The patches are about the size of a quarter.
                
Often, 12 patches are attached to your body. This helps detect your heart's electrical activity from many areas at the same time. The nurse may have to shave areas of your skin to help the patches stick.
                
After the patches are placed on your skin, you'll lie still on a table while the patches detect your heart's electrical signals. A machine will record these signals on graph paper or display them on a screen.
                
The entire test will take about 10 minutes.
                
EKG
                

                
Special Types of Electrocardiogram
                
The standard EKG described above, called a resting 12-lead EKG, only records seconds of heart activity at a time. It will show a heart problem only if the problem occurs during the test.
                
Many heart problems are present all the time, and a resting 12-lead EKG will detect them. But some heart problems, like those related to an irregular heartbeat, can come and go. They may occur only for a few minutes a day or only while you exercise.
                
Doctors use special EKGs, such as stress tests and Holter and event monitors, to help diagnose these kinds of problems.
                
Stress Test
                
Some heart problems are easier to diagnose when your heart is working hard and beating fast. During stress testing, you exercise to make your heart work hard and beat fast while an EKG is done. If you can't exercise, you'll be given medicine to make your heart work hard and beat fast.
                
For more information, go to the Health Topics Stress Testing article.
                
Holter and Event Monitors
                
Holter and event monitors are small, portable devices. They record your heart's electrical activity while you do your normal daily activities. A Holter monitor records your heart's electrical activity for a full 24- or 48-hour period.
                
An event monitor records your heart's electrical activity only at certain times while you're wearing it. For many event monitors, you push a button to start the monitor when you feel symptoms. Other event monitors start automatically when they sense abnormal heart rhythms.
                
For more information, go to the Health Topics Holter and Event Monitors article.
The exact cause of atherosclerosis isn't known. However, studies show that atherosclerosis is a slow, complex disease that may start in childhood. It develops faster as you age.
                
Atherosclerosis may start when certain factors damage the inner layers of the arteries. These factors include:
                
Smoking
                
High amounts of certain fats and cholesterol in the blood
                
High blood pressure
                
High amounts of sugar in the blood due to insulin resistance or diabetes
                
Plaque may begin to build up where the arteries are damaged. Over time, plaque hardens and narrows the arteries. Eventually, an area of plaque can rupture (break open).
                
When this happens, blood cell fragments called platelets (PLATE-lets) stick to the site of the injury. They may clump together to form blood clots. Clots narrow the arteries even more, limiting the flow of oxygen-rich blood to your body.
                
Depending on which arteries are affected, blood clots can worsen angina (chest pain) or cause a heart attack or stroke.
                
Researchers continue to look for the causes of atherosclerosis. They hope to find answers to questions such as:
                
Why and how do the arteries become damaged?
                
How does plaque develop and change over time?
                
Why does plaque rupture and lead to blood clots?