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Pernicious anemia symptoms, causes, and treatment – Pernicious Anemia

Pernicious anemia is a condition that affects red blood cells. There is a lack of B12 vitamin because of reduced intake or low absorption.

Adult pernicious anemia is more common in people of Celtic or Scandinavian origin. However, recent data shows that pernicious anemia presents worldwide with different ubiquity among several racial groups. 

You will find more information on pernicious anemia below. Directly from a doctor, you will learn the symptoms, the causes, and consequences of this condition.

What deficiency causes pernicious anemia?

It is important to keep in mind that the B12 vitamin is also known as cobalamin. Also, Vitamin B12 deficiency always causes megaloblastic anemia, besides other conditions as well.

Anemia is a syndrome (or a constellation of elements) where red blood cells (the ones that transport oxygen in hemoglobin) are low.

There are many types of anemia. Specifically, this is a kind of anemia where the red blood cells are more prominent than usual (megaloblastic anemia). Nevertheless, the term “pernicious anemia” is reserved explicitly for the cobalamin deficiency caused by the lack of the intrinsic factor (IF), which is a protein.

Parietal cells in the stomach secrete IF, where it binds to vitamin B12 from the diet. Afterward, the small intestine absorbs cobalamin along with intrinsic factor. The cause of pernicious anemia is the deficiency of vitamin B12 due to the immune system’s destruction or simply a lack due to other causes of intrinsic factor and/or parietal cells.

Beef liver has one of the highest cobalamin contents. Other foods where you can find high vitamin B12 are meat, fish, and dairy products. People following strict vegan diets or poor diets, in general, are at a higher risk of developing cobalamin deficiency.

Approximately, Vitamin B12 stores can last up to 4 years to finish, so dietary changes take time to develop. It has to be this way because this vitamin plays an essential role in cell division and is vital for your health. 

What is the leading cause of pernicious anemia?

Several conditions can cause low production of intrinsic factor. About 90% of all adults with pernicious anemia have antibodies that attack the parietal cells and the intrinsic factor.

Antibodies are proteins that your immune system uses to protect you from things that could make you sick. Sometimes, antibodies can go wrong and attack your own body, resulting in an autoimmune disease, like pernicious anemia.

Also, there is an association between anti-intrinsic factor antibodies and the development of atrophic gastritis. Atrophic gastritis is a condition where the lining or mucosa of your stomach is severely damaged. So, this disease also affects your stomach’s ability to produce the acid the normal digestion process needs.

The low acid production results in more difficult iron absorption, which could ultimately worsen the anemia. Iron deficiency is a common association to pernicious anemia. Keep in mind that the first cause for anemia worldwide by far is iron deficiency. Therefore, this will mean that there are situations in which two causes for anemia combine in one person.

Another relatively common cause of pernicious anemia includes gastrectomy. Gastrectomy is the medical term for the surgical removal of all or part of the stomach. Different types of gastrectomy are the treatment for benign tumors, bleeding, perforation, or stomach cancer.

In other cases, gastrectomy (gastric bypass surgery) can treat obesity (after other resources did not work). Since they remove the stomach (or part of it), they remove the IF-producing parietal cells. This situation diminishes the capacity of absorbing cobalamin, which could produce pernicious anemia.  

How severe is pernicious anemia?

Before the discovery of nutritional deficiency, this used to be a severe and life-threatening condition. Nowadays, after the diagnosis of vitamin B12 deficiency because of pernicious anemia, you will need life long medication.

The treatment includes injections of vitamin B12 in order to maintain your blood levels. Sometimes, your physician will need to adjust the injections for you to feel better.

Some complications could become untreatable or more severe without a timely administration of the treatment. Hence, with early treatment, you will experience a reversion of the difficulties, and you will live an expected lifespan.

Nonetheless, if you have atrophic gastritis, you may have a higher chance of developing gastric cancer. Other types of cancer associated with pernicious anemia include tonsillar cancer, esophageal cancer, acute myeloid leukemia, and myelodysplastic syndrome.

Besides atrophic gastritis, patients with pernicious anemia are more likely to develop other autoimmune diseases. Some of these autoimmune disorders are Addison disease, Graves disease, Type 1 Diabetes, Hashimoto disease, and hypothyroidism

In children, pernicious anemia is due to a lack of production of IF; therefore, complications are different. In light of this, children with congenital pernicious anemia are not likely to develop gastric atrophy. 

Who is most likely to get pernicious anemia?

As a genetic condition, some populations have a higher rate of pernicious anemia than others. Celtics (English, Scottish, Irish, etc.) and Scandinavian populations have more genetic defect cases. 

The amount of cases of these ethnic groups is around 10 to 20 cases by 100,000 people each year. In the past, doctors thought that pernicious anemia was exclusive of these groups.

Today, we know that all racial groups can develop it, mainly because tests are more available even though they remain uncommon for Native Americans or black people.

In general, pernicious anemia presents in people aged between 40-70 years, with racial variations. White people have an average age of onset of 60 years, with a younger beginning for African descents.

Congenital pernicious anemia presents before the two years of age. In some populations, it is slightly more common in women. However, there isn’t a report of this phenomenon in the United States.

Individually, the risk of developing pernicious anemia is higher when you have family members with the disease. Having an autoimmune disease like the ones mentioned previously also elevates your risk of developing pernicious anemia. As we also know, stomach surgery including gastric bypass, gastric stapling, and gastrectomy put you at a higher risk of vitamin B12 deficiency.  

What are the symptoms of megaloblastic anemia?

Usually, symptoms start being very mild and progress to a more severe condition. Some symptoms are common to all types of anemia, and others are specific to vitamin B12 and B9 deficiencies.

Common anemia symptoms include:

  • Fatigue
  • Shortness of breath
  • Dizziness
  • Paleness or slightly yellowness of the skin
  • Irregular heartbeats or chest pain

Fatigue is due to a lack of oxygen in all the tissues because fewer blood cells mean less oxygen transportation capacity. While these are common anemia symptoms, you may experience them because of other diseases. It is also common in mild types of anemia to have only a few symptoms.

On the other hand, manifestations of cobalamin or folate deficiencies are more specific. About a third of patients experience a mild fever at the moment of diagnosis.

Also, half of the patients experience weight loss due to a decrease in appetite. Digestive symptoms include changes in taste, diarrhea or constipation, nausea, vomiting, heartburn, and flatulence (gases).

Neurological symptoms can be tingling or numbing of the hands and feet, muscle weakness, loss of balance, or trouble walking. The loss of balance and difficulty walking is worse at night, which increases the risk of falling.

Moreover, the disease can affect the mind by lack of concentration, memory troubles, confusion, irritability, hallucinations, or depression. Neurologic and mental disorders are more common in elderly patients, although it can affect small children too. Some patients might experience retention of urine.  

What blood tests could indicate pernicious anemia?

The preliminary blood test your practitioner will administer in order to study your condition is a complete blood count (CBC). Your healthcare professional will draw blood from one of the superficial veins of your forearm using a needle.

Usually, with a small amount, it will be enough. The complete blood count will give your doctor information about the components of your blood.

In case you have anemia, the test will report low hemoglobin. This is a protein inside red blood cells that helps transport oxygen. The CBC will also note other information that will guide the doctor to diagnose the anemia’s underlying cause.

Another critical measure to diagnose anemia is hematocrit. Hematocrit is a measure of the space occupied by red blood cells in your blood. The doctor will explain these results to you. Other blood tests that might help your doctor make the diagnosis include: 

  • Blood vitamin B12 level: if it is low, it might indicate pernicious anemia. Some factors could interfere and create a false-normal or high result. 
  • Blood homocysteine and methylmalonic acid (MMA): high levels could indicate pernicious anemia. 
  • High bilirubin and high lactate dehydrogenase (LDH): it can indicate pernicious anemia. They can also be high in other diseases. 
  • Antibodies attacking IF or parietal cells are also good indicators that you might have pernicious anemia.  

How to diagnose pernicious anemia?

By definition, pernicious anemia is caused by cobalamin deficiency, only because of a dysfunctional production of intrinsic factor. In this sense, it is crucial to differentiate pernicious anemia from other problems that may exist in the absorption of vitamin B12.

Other issues could similarly cause low cobalamin levels or halt cobalamin absorption, leading to macrocytic anemia with the same symptoms. These other conditions that could cause macrocytic anemia include alcoholic fatty liver and alcoholic hepatitis, bone marrow diseases, and gastric cancer.

The most specific test to diagnose pernicious anemia is Schilling’s test. In this test, the healthcare professional will give you a sample of special cobalamin. If you have sufficient IF, you will absorb the vitamin B12 and, later, they will measure it in your urine.

Depending on your results, you might undergo other Schilling’s test stages to rule out all the possibilities. Even though this is the most precise test to determine if you have pernicious anemia, it is very complex. Therefore, the doctor might advise you to take other, more straightforward tests to correctly assess your condition.

When the doctor is unsure about the diagnosis, he or she may indicate a bone marrow aspiration and biopsy. These tests will help the doctor know the condition of your bone marrow.

The bone marrow is the tissue that generates all the cells that circulate in your blood. A sample will be drawn from the bone in the center of your chest or your hip’s bone. Not all patients require a bone marrow aspiration and biopsy. 

Can a full blood count detect vitamin B12 deficiency?

A full blood count will reflect your levels of hemoglobin and hematocrit. These values are enough to make a diagnosis of anemia. Nonetheless, this test does not tell the amount of vitamin B12 in your blood. Nor does it mention your stomach’s capacity to produce intrinsic factor or your intestine to absorb the cobalamin.

Besides hemoglobin and hematocrit, other values from the full blood count guide your doctor towards your diagnosis. Among these, the “mean corpuscular volume” (MCV) and the mean corpuscular hemoglobin (MCH) are significant. 

MCV is a measure of the proportions of red blood cells. MCV is high in pernicious anemia, in other cobalamin deficiencies, and other conditions. This points out that your red blood cells are more extensive than average.

Conversely, mean corpuscular hemoglobin is the amount of hemoglobin found inside each red blood cell. MCH is low in most cases of anemia. As you see, these two values may help orientate the doctor, but won’t tell for sure what you have.

A full blood count will also report other values that include platelets and white blood cells (or leukocytes). Platelets are blood cells in charge of forming clots to stop bleedings when you cut or have an accident. And white blood cells are the ones in charge of fighting infections. They are part of your immune system. Abnormal platelets and leukocytes’ results might indicate other diseases besides pernicious anemia.  

Can you treat pernicious anemia with oral B12?

Doctors know that it is easy for patients just to swallow a pill. Despite that, taking oral supplements of vitamin B12 will not solve your pernicious anemia.

The best cobalamin source is the food we eat, but that cobalamin isn’t absorbing because of the lack of IF. However, in some cases, when you have B12 deficiency from other causes, oral cobalamin can be an option.

In the case of gastrectomy, it depends on the type of surgery you had. The surgeon, nutritionist, and other healthcare professionals will guide you towards the best choice to fulfill your cobalamin needs. Probably, you will eventually need injected vitamin supplements.

In the case of pernicious anemia, a group of professionals will help you choose the best treatment option. That group might include your general practitioner, a gastroenterologist (for digestive symptoms), a hematologist (for the anemia), and a neurologist (for your nervous system). Each doctor might ask for specific tests to ensure your full wellbeing. From those results, they might decide other treatments besides vitamin B12, depending on the severity of your disease. 

Treatment for cobalamin deficiency varies and depends on how important it is. Probably at the beginning, you will need injections once or twice a week. Later in the treatment, you will most likely receive one intramuscular or subcutaneous injection every month.

In some extremely severe cases of anemia, the doctor might advise administering blood transfusions. Even though blood transfusions are not a regular part of the treatment. 

What happens if pernicious anemia is left untreated?

In most cases, the doctor will be able to determine the presence of anemia before you develop severe symptoms. The treatment with vitamin B12 injections will solve most of your complications.

If you live with anemia for an extended period, your heart will develop complications. These heart complications include irregular heartbeats, heart murmurs, enlarged heart, or heart failure.

Heart murmurs are an abnormal type of noise your physician hears while examining your heart that can be normal or indicate underlying issues. Heart enlargement and heart failure happen because your heart tries to compensate for the decrease in your blood’s transport function. While trying to balance, the heart has to work more than usual and get hurt.

On the other hand, your digestive system’s cells can also have problems because of the cobalamin deficit. This situation can result in severe cases of diarrhea or vomiting.

Also, some patients with pernicious anemia could develop stomach polyps. These are abnormal tissue growth that originated in the mucosa (the internal layer of your stomach).

Polyps can progress into cancer cases in some cases of autoimmune gastritis (your immune system attacks the stomach). You must regularly visit your gastroenterologist to prevent and treat complications.

The nerves use vitamin B12 to produce myelin. Myelin is a substance that helps your nerves work correctly. When you don’t have sufficient myelin, you start experiencing neurological symptoms, as mentioned in the section above. If you don’t treat them, the loss of balance, muscle strength loss, and numbing could be irreversible. The same could happen with memory loss.

Bone fractures are also common complications. Loss of balance and higher fragility of the bone cause bone fractures. Importantly, female with pernicious anemia can have a false positive Pap test (also called Pap test of vaginal cytology).

What are the possible complications of pernicious anemia in a child?

Pernicious anemia in the child is a rare condition. Usually, children with pernicious anemia don’t have anti-IF antibodies. Vitamin B12 deficiency is more common in them because of other causes of incorrect cobalamin absorption.

Besides, folic acid deficiency can also cause megaloblastic anemia. Children with pernicious anemia have a specific problem where parietal cells are unable to produce the intrinsic factor.

Complications depend on the age of the kid and the time taken to correct the deficiency. Cobalamin stores in the body are usually big enough to cover the needs for an extended period.

During the first year, cobalamin stores depend on how much vitamin was available during pregnancy. After that, the mother’s milk and other foods provide vitamin B12 needed.

Doctors might prescribe vitamin B12 supplements (oral or through an injection) in the case of strictly vegan mothers. If a deficiency occurs during pregnancy, it might manifest in children as soon as 3 or 4 months of life.

The most common complications in younger children include severe anemia and neurologic defects (which could be irreversible). Neurologic defects include developmental delay or regression, involuntary movements, paralysis, seizures, loss of muscle strength, and muscle control.

In older kids, symptoms are more similar to the adult and include numbing the limbs or memory loss. Sometimes trouble with concentration can be evident in school or other activities.

Anemia complications and symptoms are the same as the adult: weakness, fatigue, pale skin, and heart disease (long term). All kids experience some delay in their growth since cobalamin is needed for cells to divide. If your child has a tardy development and neurologic symptoms, your doctor will investigate for cobalamin deficiency. Even small deficiencies can have severe effects if left without treatment.    

Can you drink alcohol if you have pernicious anemia?

Heavy alcohol consumption can reduce the capacity of your intestine to absorb vitamin B12. Also, alcohol affects the ability of your bone marrow to produce new blood cells in many ways.

Even if your pernicious anemia is under control with the cobalamin injections, a “safe alcohol amount” doesn’t exist. Heavy drinking also affects your liver, causing ineffective erythropoiesis (the process of creating new red blood cells).

The same liver condition can cause different blood disorders, which will make your anemia much worse. Alcohol can increase the severity of your gastric disease and heighten the cancer risk.

Can anemia turn into leukemia?

Pernicious anemia, cobalamin deficiency, and folate deficiency interfere with normal cell division. In this sense, it can put you at a higher risk of developing some types of cancer.

This risk of cancer exists even while the anemia is under control. One of those cancers is acute myeloid leukemia (AML).

AML and all leukemias are a type of cancer that affects some of the cells in your blood. If your anemia previously responded to B12 therapy and now is under control, the doctor might suspect AML. The symptoms can be very unspecific. The physician will guide your tests to get an accurate diagnosis.

With pernicious anemia, you also have a higher risk of developing myelodysplastic syndrome (MS). A condition in which your bone marrow is unable to produce enough red blood cells. People with MS also have a higher risk of developing acute myeloid leukemia.

Do you think you have symptoms of this disease?

This tool is a Pernicious Anemia Symptoms Checker. It gathers the most important signs, symptoms, and risk factors for this condition. Therefore, it would tell anybody who uses it the likelihood that their symptoms are because of Pernicious Anemia. Notably, this tool is free to use and would only take a few minutes.

What do you think?

Written by Dr. Esteban Kosak

Doctor of Medicine - MD Recently Graduated from Medical School and inspired to aid the global population during this situation. I think that we shall no longer be waiting to see a doctor when we feel sick. Several times we feel disease searches in Google drive us to a rabbit hole and come out thinking that we may die of cancer or something very serious, given that symptoms may seem to fit a wide variety of illnesses. Since I recently graduated from medical school. I have all the medical information fresh in my mind. My thorough experience as an expert researcher allows me to very-well known the different diseases and conditions that affect human bodies. Empowered by the United Nations 17 Sustainable Development Goals (SGDs). I think that we all can provide a grain of sand to help humanity. That's why we created Symptoms.Care a place where you can come and screen your symptoms and find what different illnesses can be related to them. Armed with the right information you can instantly, discretely, secure and from the comfort of your home talk with a Doctor that can Evaluate your Symptoms and help you seek the right treatment.


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