Anaemia is a condition where there is a reduced number of red blood cells. Haemoglobin is the red blood cells that carry oxygenated blood to all the tissues in the system. Pernicious anaemia is categorised by the presence of large, immature, nucleated cells circulating in the blood, caused due to an autoimmune process by impaired uptake of vitamin B12 due to lack of intrinsic factor in the gastric mucosa.

Deficiency of vitamin B12 also results in pernicious anaemia, as the body needs this vitamin to aid red blood cell production. This condition is sometimes linked with other autoimmune diseases such as Grave’s disease, Hashimoto’s thyroiditis and vitiligo. Pernicious means destructive, injurious or deadly.
Pernicious Anaemia Causes

Pernicious anaemia is a rare condition, mostly seen in older adults above 60 years of age and about 50% of adults with vitamin B12 deficiency also develop this disorder. The condition once diagnosed can be effectively treated with vitamin B12 injections or supplementation. However, if untreated can lead to serious complications.

Also Read: Anaemia: Causes, Symptoms And Treatment


The human body needs healthy red blood cells to carry oxygen and nutrients to all the vital organs in the system. Vitamin B12 holds a significant role in this process, if the body does not absorb adequate amount of vitamin B12 from the diet, red blood cells will be too large to travel in the body. As a result of this, the body makes very less red blood cells and these larger cells die off sooner. This is often caused due to the lack of stomach protein called intrinsic factor (IF), which supports vitamin B 12 absorption by the small intestine and also along in the digestive process.

Also Read: Vitamin B 12: Deficiency, Symptoms And Treatment

Some of the other health conditions that may cause pernicious anaemia include:

Autoimmune diseases, like Type 1 diabetes

Crohn’s disease

Partial removal of intestine or stomach


Certain medications like antacids or drugs that treat diabetes mellitus, can make it difficult for the system to absorb vitamin B12 effectively.

Vegetarians and vegans are at risk of developing pernicious anaemia, as vitamin B12 sources are abundant in animal products.


The progress of pernicious anaemia is very mild, hence, it may be difficult to recognize the symptoms in the initial stage. Some of the common signs and symptoms include:


Shortness of breath

Feeling dizzy

Cold hands and feet


Chest pain

Weight loss

Pale skin

In more severe cases, a person with pernicious anaemia may develop neurological symptoms which include:

Numbness in the arms and legs

Poor balance and coordination

General muscle weakness


Trouble focussing





Poor appetite

Heart burn

Diagnosis And Treatment

Some of the blood work suggested by the doctor to diagnose pernicious anaemia includes:

Complete blood count test measures haematocrit levels and haemoglobin that can screen for anaemia.

Vitamin B12 level measurements.

Examination of a blood smear under a microscope.

Measure autoantibodies to intrinsic factor or stomach lining cells.

Blood levels of iron and iron-binding capacity.

Folate levels.

Blood levels of homocysteine or methylmalonic, both of which are sensitive indicators of vitamin B 12 deficiency.

Bone marrow aspiration or biopsy may be suggested in some cases if bone marrow disorders are suspected.


The mode of treatment for pernicious anaemia is aimed at correcting vitamin B 12 deficiency.

Vitamin B 12 injections are periodically given and assessed, making necessary adjustments in vitamin B12 dosing. An injection of 1mg of vitamin B 12 is given every day for one week, followed by 1 mg every week for four weeks and thereafter 1 mg every month.

Once vitamin B12 levels are normal, the doctor may recommend the patient to take vitamin B 12 supplements instead of injection.

The doctor may also suggest the patients to modify the diet and include foods abundant in vitamin B12 to correct the deficiency and improve overall health.