e. Hemophilia. Hemophilia is usually a hereditary disease characterized by a
lack of one of the factors necessary for the clotting of the blood. Hemophilia is a
disease that occurs more commonly in men than women. Patients who have
hemophilia do not usually develop massive hemorrhages, but rather slow oozing or
trickling of blood. The primary danger with hemophiliac patients is trauma involving
severe bleeding. In these cases, the patient may soon die because of a severe loss of
blood that will occur if the missing clotting factor is not soon administered.
f. Leukemia. Leukemia is a disease of the white blood cell forming tissue. It
is characterized by an abnormally high white blood cell count. During the progression of
the disease, the white blood cells gradually crowd out the erythrocytes and in some
cases the leukocytes phagocytize (engulf) the red blood cells.
g. Mononucleosis. Mononucleosis is an extremely contagious disease
characterized by an abnormally large number of one type of white blood cells (the
monocytes). The disease affects the lymph tissue and is characterized by fever, sore
throat, and inflamed lymph nodes. The spleen may become enlarged and lassitude
(general tired feeling) on the part of the patient is not uncommon. Mononucleosis is
thought to be a disease of viral origin that usually strikes people between the ages of
ten and thirty-five. The treatment of mononucleosis is symptomatic. The disease
usually runs its complete course in about four to six weeks.
h. Pernicious Anemia. Pernicious anemia is caused by the inability of the
body to absorb vitamin B12 from the intestine. This failure to absorb vitamin B12 is
caused by a lack of the intrinsic factor that is normally secreted by the parietal cells in
the stomach. The presence of this intrinsic factor is needed in order to absorb vitamin
B12. Perncious anemia rarely affects persons under the age of thirty-five. It is more
common in persons of English, Scandinavian, and Irish descent. It may be difficult to
detect this condition because there are few outwardly visible signs associated with it.
As with all anemias, fatigability is usually the first noticeable symptom. The red blood
cells are large and oval. The treatment of pernicious anemia centers on the parenteral
administration of vitamin B12 (cyanocobalamin) which must be continued for the
remainder of the patient's life.
DISORDERS ASSOCIATED WITH THE CIRCULATORY SYSTEM
NOTE: Two rather acute disorders that affect the circulatory system are a thrombus
and an embolus. They are not considered diseases, but acute disorders.
a. Thrombus. A thrombus is a clot formed in a blood vessel that remains
attached to the wall of the vessel. A thrombus can conceivably occur in any blood
vessel. However, they are of primary concern when they occur in vessels serving vital
organ systems such as the liver, kidneys, brain, and heart. Thrombi frequently get
larger within the vessel and, if untreated, may eventually lead to complete blockage of
the vessel. Such a blockage could lead to an infarction, an area of necrosis in a tissue
or organ that results from the obstruction of circulation to that area.