How does Pernicious Anemia Affect the Body?

illustration of the effect of Pernicious Anemia on the body


Pernicious anemia is a rare chronic type of blood disease wherein the body produces a few red blood cells due to vitamin B12 deficiency. The primary cause of this condition is the lack of Intrinsic Factor, a gastric protein that is needed by the body to be able to absorb dietary vitamin B12 through the intestine.

Vitamin B12 is essential for some of the most important body functions such as the formation of red blood cells, DNA synthesis, and neurological functions. It helps the body produce healthy red blood cells and keep the nerve cells healthy. It can be found in foods such as fish, meat, milk, eggs, dairy products, and seaweed.

Symptoms of Pernicious Anemia

Early Onset or Common Symptoms

The onset of pernicious anemia is slow and steady that it may take decades to diagnose the disease. The symptoms do not usually appear before 30 which makes the disease undiagnosed most of the time. The exception is when pernicious anemia is developed at a younger age which is in the case of the other forms of pernicious anemia such as congenital and juvenile pernicious anemia. The early onset or common symptoms of pernicious anemia may include:

  • Extreme Fatigue
  • Weakness
  • Tachycardia or an unusual or abnormally rapid heart rate
  • Shortness of breath
  • Chest pains
  • Brain fogs
  • Dry skin
  • Flaky and brittle nails
  • Lack of coordination or clumsiness

Neurological Symptoms

Some symptoms of pernicious anemia can also overlap with the symptoms of B12 deficiency. These symptoms are brought about by the lack of B12 which is essential in some neurological functions. These symptoms are:

  • Difficulty balancing when walking or gait problems
  • Impaired sense of smell
  • Sensory impairment
  • Dizziness or feeling faint
  • Vomiting and nausea
  • Numbness and tingling sensation like needles and pins
  • Burning of the legs and/or feet
  • Vertigo
  • Fibromyalgia or neuropathic pain
  • Tinnitus

Behavioral Changes

The neurological symptoms of pernicious anemia may also be accompanied by behavioral changes such as:

  • Irritability, impatience, or frustration
  • Confusion or dementia
  • Depression
  • Sudden mood swings
  • Insomnia or inability to sleep
  • Loss of libido

Gastrointestinal Symptoms

Oral Cavity Symptoms

  • Bleeding gums
  • Swollen or ‘beefy’ tongue
  • Mouth ulcers
  • Cracked tongue

Other Reported Symptoms

  • Jaundice or the yellow colouring of the skin
  • Megaloblastic anemia or the condition where large immature red blood cells impair the ability of blood to transport oxygen to the different tissues of the body
  • Premature grey hair
  • Hair loss
  • Vision problems
  • Menstrual problems
  • Infertility
  • Incontinence

Co-existing Conditions

Pernicious anemia is believed to be an autoimmune disease as the body produces antibodies that impair the cells in the stomach lining which are responsible in creating Intrinsic Factor which is essential for the body to absorb vitamin B12 from food.

It is still uncertain why individuals affected with one autoimmune disease usually also develop other autoimmune conditions. Some may have one while others may have several other conditions. Here are the most common autoimmune diseases that coexist with pernicious anemia:

Effect of Pernicious Anemia on the Body

Most of the patients with pernicious anemia are diagnosed in their forties. Since there are many instances that pernicious anemia goes undiagnosed and untreated, it can cause permanent damage to the nerves and other organs. It can also raise the risk of developing stomach cancer.

Severe B12 deficiency can cause progressive damage to the nerves and the spinal cord. This brings about gait or balancing problems when walking and it also gives the tingling sensation or numbness felt in the feet. Pernicious anemia can damage the optic nerves and cause neurological and psychiatric problems. In rare cases, individuals affected by the disease may have memory loss, spasticity or tightness and stiffness in the muscles, unsteady gait, peripheral neuropathy or numbness in the legs and arms, and progressive lesions of the spinal cord.

Most individuals diagnosed with pernicious anemia require constant and lifelong monitoring and treatment. This is to prevent further complication and long-term damage. Long-term damage includes:

  • Weight loss
  • Difficulty swallowing
  • Upset stomach
  • Iron deficiency

Complications of Pernicious Anemia

Since pernicious anemia is usually diagnosed at a later age in life, there can be some possible complications of the disease especially if it is left undiagnosed or untreated.


Although some complications brought about by pernicious anemia can be reversed by taking in vitamin B12 supplements and changing the diet, most of these complications become permanent.

Once a patient is diagnosed with pernicious anemia, it is recommended to have regular check-ups with the doctor so that he/she can monitor the patient closely and on a long-term basis. In this way, the doctor can easily identify and treat possible serious effects of pernicious anemia. Potential complications of pernicious anemia include:

  • Digestive tract problems
  • Nerve damage
  • Confusion, memory problems, and other neurological symptoms
  • Heart damage

These complications are usually an effect of long-lasting pernicious anemia.

The most deadly and dangerous complication of pernicious anemia is gastric cancer.
The doctor can check for a possible development of cancer during regular visits and through biopsies.