Notes by dr Claudio Italiano
(cf >> anemias) (see also microcitemie).
WBC, which means white blood cells, in our example are 6.080 because it multiplies the value of 6.08 x 1000 and in the next column read the values in the standard between 4000 and 10.000. Then read the red blood cells, in our case are 4,59 that multiply x 1,000,000, then 4,590,000, so I read the most important value, the content in hemoglobin in grams per deciliter, here 13.30 grams per deciliter it is a patient of mine), the hematocrit, that is the corpuscular share compared to the liquid one, and therefore our famous MCV value, that is the volume of the red blood cell, which in this case is 84.70, then in the norm. If, on the other hand, this value is high, then there is talk of macrocytic or megaloblastic anemia. It is clear that in the case of severe anemia the value of hemoglobin in g / dl will be very low, e.g. 7-8 g / dl. Megaloblastic anemia is one of the most frequent anemic conditions in internal medicine. As we know, to talk about anemia, we need to have a reduced amount of hemoglobin in grams, usually below 9.5 grams / dl, and, if we look at it, the corpuscular volume of the red blood cell or MCV (see image of the blood count) we will be able to distinguish the microcytic forms from the megaloblastic ones, checking the values in micron cubes of the cells, which in our case are always more than 100 micron cubes.
This form is characterized by the presence in the marrow and sometimes also in the bloodstream, abnormal megaloblasts, ie cells derived from erythroblasts, ie the precursors of erythrocytes that are notably large for a defect that results from the lack of vitamin B12 (introduced with the diet and contained in animal proteins, in meat, fish, eggs, milk, and in small quantities with vegetables.) and of folic acid, but these latter forms are more evident in the patient addicted to alcohol. This vitamin is absorbed in the terminal ileum, so in Crohn's disease it can have an alteration of its absorption and the same in atrophic gastritis, where it is known that Castle's factor is the basis of its absorption. The cell, that is, grows without dividing and the nucleus takes on large dimensions. Folic acid is essential in the synthesis of methionine, an amino acid important for the synthesis of red blood cells and in pregnancy its value can be lowered, and the same applies to vitamin B12. The megaloblastic alterations are therefore due to alterations of DNA synthesis, while the synthesis of the continuous RNA, giving rise to an increase in the mass and maturation of the cytoplasm, but not of the nucleus of the cell. Megaloblast remains in the bone marrow where an ineffective erythropoiesis is determined because the cell breaks and dies releasing indirect bilirubin and increasing the amount of uric acid in the blood. But vitamin B12 deficiency is also responsible for damage in the synthesis of other haematopoietic bone marrow cell lines, in particular the synthesis of thrombocytes (thrombocytopenia) and leucocytes, with leukopenia and changes in the segmentation of neutrophil granulocytes, which are hypersegmented, always because of ineffective erythropoiesis.
- anemia due to folic acid deficiency, but it would be more correct to define
them as macrocytes;
- B12 deficiency anemias, which in turn are divided into pernicious anemia and
other forms of vitamin B12 deficiency, usually from drugs that interfere in the
use of folic acid, for example cytotoxic, anticancer, purine analogues and
pyrimidines that are, so to speak, the "building blocks" of DNA or
immunosuppressive drugs.
- Guglielmo syndrome, which is considered a myelodysplasia that changes into a
form of acute myeloid leukemia. Clarification of etiology and pathophysiology is
of crucial importance in megaloblastic anemia.
a) insufficient food intake, see foods containing vitamin B12
b) malabsorption due to gastric intrinsic factor deficiency, gastrectomy
c) diseases of the terminal ileum, such as ileitis, tropical sprue, intestinal
resection, carcinomas; or gastric polyposis, atrophy of the gastric mucosa for
chronic gastritis,
d) parasitosis, cestodes, fish parasites, intestinal bacteria and drugs, ac.
paraimmosalicilico.
e) are secondary to B12 deficiency if the vitamin is not introduced with the
diet (vegetarian anemia and megaloblastic anemia of the infant,
Cobalamin is located in a tetrapyrrole ring like heme, but it can not be
synthesized and is found in meats and cheeses. The requirement is 2.5 micrograms
/ day; during digestion there is a glycoprotein carrier that carries it into
the stomach; the intrinsic factor, produced in the stomach, weighing 50 kDa,
from the parietal cells of the stomach, allows the absorption of B12 in the
terminal ileum, where the Intrinsic + Vit.B12 complex is internalized and the
absorbed vitamin. The role of vit B12 lies in its role in the formation of
cobalaminic enzymes that intervene in the transfer of methyl groups to 5 methyl
tetrahydrofolate up to the formation of 5.10 methyl tetrahydrofolate. Therefore
in the first therapies it is necessary to administer Vit. B12 and then also
folic acid; in fact both the two vitamins intervene in enzymatic reactions for
the synthesis of nucleic acids (DNA), and therefore for the replacement of
tissues, restoration of the structures of the Central Nervous System.
Anemia perniciosa or M. of Addison-Biermer, due precisely to the lack of the
so-called intrinsic factor, produced at the antral level that allows the
absorption of the vitamin. It is deficient in chronic atrophic gastritis. Compare
asthenia, post-prandial sense of epigastric weight (pain), occasional diarrhea,
sensations in the tongue (Hunter's glossitis), neurological disorders due to
demyelination with axonal degeneration; the disturbances range from paresthesia,
difficulty in grasping objects or walking or psychic as apathy, diminution of
memory, depression, dementia and psychosis.
a) Check the blood count, the values of the hemoglobin content in g / dl and
the value of MCbV.
b) Schilling test: performed to study pathogenesis; a dose of radioactive
cobalamin per os is administered and the proportion of radioactivity excreted
with the 24-hour urine is investigated; if there has been malabsorption in the
urine there is no radioactivity; at this point the intrinsic factor + vit. B12
and repeat the operation; in this case or the absorption occurred and therefore
the reason for the Vitamin B12 deficiency resided in the intrinsic factor
deficiency, or the absorption did not occur for other causes that must be
identified for ex. in stunting loop syndrome, in bacterial contamination.
c) to dose the values of cobalamin go in the serum between 200- 900 pg / ml;
values below 100 pg / ml indicate notable deficiencies and folic acid;
Folate deficiency.
First of all, exclude the Vit B12 deficit because folate administration can make
the picture worse. A normal diet containing folic acid can not cause this
affection, which, however, is typical of alcoholism, celiac disease, idiopathic
steatorrhea, hemodialysis, chronic hemolytic anemias.
a) insufficient intake of food but it is rare because the vitamin is contained
in vegetables;
b) ethylism
c) increased needs: pregnancy, lactation, growth, neoplasia, chronic skin
desquamating diseases, hemodialysis;
d) malabsorption syndromes, tropical and non-tropical sprue
e) drugs, barbiturates, ethanol, methotrexate, azathioprine, hydroxyes.
Folates intervene as coenzymes in the transfer of carbon units in the form of
methyl groups, the source of which is serine. Example: the synthesis of purines,
Anemia due to bone marrow failure: may sometimes mask macrocytic anemia
Aplastic or arygenerative anemia, is characterized by pancytopenia
or depression
of the red and / or white and / or platelet series. It can occur as a toxic
reaction to different chemicals, to medicaments (benzol, arsenobenzoli,
anticonvulsants, quinine, pyramidone, hair dyes, chemotherapeutic and
antiblastic, ionizing radiations, X rays). Laboratory: red blood cells
<1,000,000, white blood cells under 2000 / mmcube, neutropenia and relative
lymphocytosis; fever appear, and concomitant septic facts. Macrocytic red blood
cells may occur.
Pure aplasia of the red series. It is associated with thymic tumors in 30-50% of
adults. Anti-red cell precursor antibodies have been described.
Myelodysplastic anemia. Myelodysplastic anemias called refractory anemias with
excess blasts, preleukemia, dysmytropoietic syndrome or chronic erythremal
myelosis have in common a primitive abnormality of the marrow with disorder and
maturation and insufficiency to produce an adequate number of mature red blood
cells.
It is always left to the hematologist specialist, especially in serious forms! There is no single therapy for all anemia! In the macrocytic and / or megaloblastic forms, Vit B12 (1000 gamma / day for short periods) and folic acid (1-5 mg / day) are administered. Iron is not recommended in haemolytic forms.
Let us also remember that some megaloblastic anemias, with a low production of
reticulocytes, can be framed as myodysplastic anemia, so it is necessary to
carry out second level investigations, for example. medullary biopsy
should be performed.
IN EVERY CASE THERAPY IS A STRICTLY MEDICAL ACT AND, TALORA, HIGHLY SPECIALIST
Hematology index