Pernicious anemia is a disease caused by a reduced absorption of vitamin B12 (cyanocobalamin). The main symptoms of pernicious anemia are both symptoms related to the presence of megaloblastic anemia (tiredness, fatigue, confusion), both from the deficiency of vitamin B12 it gives neurological symptoms (loss of strength and sensitivity up to paranoid ataxia and dementia) e gastrointestinal symptoms (glossitis, abdominal pain, digestive disorders).

Pernicious anemia is a disease caused by a reduced absorption of vitamin B12 (cyanocobalamin). Vitamin B12 is essential for the correct maturation process of red blood cells (erythrocytes) and is taken through the diet.

The term anemia it means that there is one in the blood deficiency of red blood cells (erythrocytes or red blood cells), or that, even with a normal number of erythrocytes, the quantity of hemoglobin is less than normal.

Say anemia or low hemoglobin it therefore assumes a similar meaning.

L'pernicious anemia it is also called megaloblastic anemia or macrocytic anemia as the red blood cells (erythrocytes) are larger than normal. The measure of the volume of erythrocytes is given by the parameter MCV o mean corpuscular volume (mean corpuscular volume). L'pernicious anemia will therefore be characterized by low hemoglobin and high MCV.

The presence of large red blood cells is linked to vitamin B12 deficiency. L'pernicious anemia in fact it is characterized by the absence of a particular factor called intrinsic factor which is essential to absorb vitamin B12 in the stomach.

In pernicious anemia our stomach is attacked by an autoimmune process, that is an immune process caused by our own organism: the gastric mucosa particularly in his glandular component is damaged and atrophies. There lack of intrinsic factor it is precisely linked to the atrophy of the glandular gastric mucosa, which also produces less hydrochloric acid.

The immature erythrocytes they are said megaloblasts and are destroyed more and earlier than normal red blood cells (causing, among other things, an increase in indirect bilirubin in the blood).

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Vitamin B12 and pernicious anemia

Vitamin B12 is mainly present in meat-based foods, and in our body it is concentrated in the liver (in the liver), where it is stored in stocks of a few mg which can however guarantee coverage of our body needs for long periods. of time (up to five years).

Vitamin B12 is absorbed in the lower part of the small intestine, which is called ileum.  Not surprisingly, partial or total ileal excision carries a considerable risk of developing macrocytic anemia.

At the gastric level, in the presence of sufficient quantities of acid gastric juices (hydrochloric acid), the cyanocobalamin present in food is bound to a protein present in the saliva, the salivary polypeptide R. Thus bound, once it reaches the duodenal portion this complex is dissolved enzymes produced by the pancreas (pancreatic proteases) and vitamin B12 binds to the intrinsic factor (Castle factor) produced by the gastric parietal cells. The final absorption of the vitamin B12-intrinsic factor complex occurs as already mentioned in the ileum.

It should be highlighted how a reduced quantity of vitamin B12 (about 1-2%) can be absorbed even without being linked to the intrinsic factor, that is by simple diffusion: this is why the therapy of pernicious anemia is based on oral supplementation of vitamin B12 in doses consistent and administered a short distance from each other.

Pernicious anemia symptoms

This kind of macrocytic anemia it may initially be asymptomatic. Often neurological symptoms appear before the symptoms of anemia real.

Between symptoms of pernicious anemia let's remember the classic symptoms of anemia, namely:

  • asthenia (tiredness)
  • easy fatigue
  • shortness of breath after even small efforts
  • hyporexia (loss of appetite)
  • skin paleness (pale skin)
  • jaundice (yellow skin)
  • nails that break easily
  • hypothermic extremities (cold hands and feet)
  • difficulty concentrating
  • memory loss
  • depression
  • disturbances in balance
  • sleep disturbances with changes in the normal sleep-wake rhythm
  • sense of (dullness dizziness)
  • in the most severe cases angina or cardiac ischemia due to discrepancy: that is, cardiac chest pain or cardiac ischemia linked to the low amount of hemoglobin present in the blood, which therefore cannot carry enough oxygen to meet the needs of body tissues.

Often pernicious anemia is also accompanied by a defect in the synthesis of megakaryocytes and consequently of platelets: there may therefore also be:

  • ease of bleeding, with the risk of spontaneous bleeding
  • thrombocytopenia (thrombocytopenia)

To these are added the symptoms of megaloblastic anemia linked to a lack of vitamin B12. THE symptoms of vitamin B12 deficiency they are mainly gastrointestinal symptoms and neurological symptoms.

Pernicious anemia gastrointestinal symptoms

In people suffering from pernicious anemia, there are often gastrointestinal symptoms. These manifestations are due to myelin degeneration affecting the nerve endings that innervate the digestive system (Aeurbach's plexus, Meissner's plexus and nerves that are part of the celiac ganglion system).

  • glossitis: called Hunter's glossitis, an inflammation of the tongue that is red at the edges and tip, itchy or painful, and smoother at the level of the flat part.
  • dysgeusia (alteration in the perception of flavors)
  • abdominal pain
  • constipation
  • diarrheal episodes
  • dyspepsia (difficult digestion)
  • hypergastrinemia: gastrin is produced to stimulate the gastric secretion of hydrochloric acid. If production is reduced or absent, gastrin is produced in increased quantities to try to compensate
  • hypochlorhydria (reduced production of hydrochloric acid HCl in the stomach) or even achlorhydria (absent production of acidic juices in the stomach)

Pernicious anemia neurological symptoms

  • loss of sensation (in particular of the sensitivity of position and vibration of the limbs)
  • decrease in strength (usually moderate)
  • loss of osteo-tendon reflexes

In the later stages of pernicious anemia from vitamin B12 deficiency the neurological symptoms become more important, with the appearance of:

  • spasticity
  • positivity of Babinski's sign
  • worsening of the sensitivity deficit of the lower limbs
  • ataxia (lack of muscle coordination), often in its spastic variant (spastic ataxia)
  • blindness to some colors (typically blue and yellow)
  • paranoid syndrome (also referred to as "megaloblastic madness“)

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