Blood - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 16

Tabl e 1. 9. Anemia grading.

Grade Degree Hemoglobin

0 Normal 12-16 g/dl (women)

14-18 g/ dl (men)

1 Mild 10-12/14 g/dl

2 Moderate 8-10 g/dl

3 Severe 6.5-8 g/dl

4 Life threatening < 6.5 g/dl

1.4.1 Blood Cell Disorders

Hematological disorders 33 comprise: (1) blood cell underproduction, such as
anemia and thrombopenia, and non-tumoral (e.g., polycythemia vera and essential
thrombocytosis) and cancerous (e.g., leukemia) overproduction; (2) abnormal co-
agulation (e.g., hemophilia and thrombophilia); and (3) blood infections (parasitic,
viral, or bacterial infections).
Erythrocyte diseases include: (1) anemias (iron deficiency, genetic sickle-cell dis-
ease, thalassemia, spherocytosis, autoimmune pernicious anemia, aplastic anemia
due to dysfunctional erythropoiesis, aplasia, hemolysis); (2) erythrocyte infections,
such as malaria (caused by Plasmodium falciparum, vivax, ovale, and malariae) and
trypanosomosis (e.g., Chagas disease); (3) polycythemias or erythrocytoses with
increased blood viscosity; and (4) several microangiopathic diseases. In addition,
toxics can bind to hemoglobin and, in some cases, create irreversible damage.
Inhaled carbon monoxide irreversibly binds to hemoglobin to form carboxyhe-
moglobin, thereby limiting oxygen transport in the blood circulation.
Anemia is due to acute or chronic factors. Anemias are classified according to the
hemoglobin level (Table 1.9 ). Injuries are common examples of acute anemias by
hemorrhage. Another usual cause is cancer. Tumor anemia is due to tumor bleeding,
hemolysis, and deficiency in folic acid and vitamin-B12. Release of cytokines,
especially interferon- , impairs erythro-

poietin synthesis in the kidney. Activation of macrophages can lead to a shorter
erythrocyte half-life and a decrease in iron use. Chemotherapy and radiotherapy
further aggravate anemia. Recombinant human erythropoietins (epoetins) avoid
transfusions, but thromboembolic complications have been observed [ 24 ].
Platelet and leukocyte deficiencies can also occur. Thrombocytopenia and
leukopenia can result from damage to hematopoietic stem cells or precursors.
Lymphocytopenia (or lymphopenia) can be also due to lack of zinc, long-term
heavy alcohol consumption, and certain infections. Human immunodeficiency virus
(HIV), a lentivirus of the retrovirus family, causes acquired immunodeficiency
syndrome (AIDS), as it invades leukocytes.

γ , interleukin-1, and tumor-necrosis factor- α

33

αια
: blood, bloodshed.