Aplastic Anemia

I.

INTRODUCTION

Aplastic anemia is a rare, non-contagious and often life-threatening disorder that results from the unexplained failure of the bone marrow to produce red blood cells, white blood cells and platelets. A decrease in the production of blood cells means that patients are more susceptible to bleeding, fatigue and infections. (Bare and Smeltzer, 2004) Internationally, the annual incidence of aplastic anemia in Europe, as detailed in large, formal epidemiologic studies, is similar to that in the United States, with 2 cases per million populations. Aplastic anemia is thought to be more common in Asia than in the West. The incidence was accurately determined to be 4 cases per million populations in Bangkok, but may be closer to 6 cases per million populations in the rural areas of Thailand and as high as 14 cases per million populations in Japan, based on prospective studies. This increased incidence may be related to environmental factors, such as increased exposure to toxic chemicals, rather than to genetic factors because this increase is not observed in people of Asian ancestry who are presently living in the United States. (http://en.wikipedia.org/wiki/Aplastic_anemia) In the Philippines, a descriptive study of 47 male and 23 female patients with aplastic anemia referred during the period January 1979 - December 1981 was undertaken at the Philippine General Hospital. Insecticides, which were either organophosphates or organochlorines, were implicated in 21 patients. The probable causes of the onset of this disease are due to intoxication of harmful chemicals. (http://www.aamds.org) Here in Tagum City, there are no documents and data showing the percentage of people suffering from aplastic anemia yearly, because it is rarely found condition in this place. Aplastic anemia is caused by a failure of the bone marrow, leading to insufficient production of peripheral blood element. The marrow failure is due to primary defects in, or damage to, the stem cell or marrow microenvironment. The disorder is characterized by a severely hypoplastic (underdeveloped) fatty marrow that is devoid of all three hematopoietic cell lines (erythroid, myeloid, and megakaryocytic). As such, this has a very strong relationship to our concept fluids and electrolytes. Hypovolemia, as one of the complications of aplastic anemia, is a fluid volume disturbance when the loss of extracellular fluid volume exceed the fluid intake. Occurs when water and electrolytes are lost in the same proportions as they exist in normal body fluids, so that the ratio of serum electrolyte to water remains the same.

OBJECTIVES General: 1. To fully understand the underlying disease process of aplastic anemia. Specific: 1. To identify the epidemiological data of aplastic anemia globally, nationally and locally. 2. To learn about the major etiologies of aplastic anemia. 3. To determine the previous and present clinical history of the patient. 4. To perform physical assessment with special attention on the systems focus. 5. To show the laboratory examination results with the corresponding normal values, actual result from the patient, and it interpretation. 6. To understand the anatomy and physiology of the blood and blood formation and its pathology during aplastic anemia. 7. To trace and understand the pathophysiology of aplastic anemia. 8. To learn the basic principle of medical management of aplastic anemia. 9. To use the nursing process to identify nursing problems from the client and provide the appropriate nursing care plan. 10. To understand the pharmacological management set on the client and provide nursing interventions. 11. To identify the discharge plan for the patient’s rehabilitation to conduct an evaluation of the client’s condition from admission to present.

ANATOMY AND PHYSIOLOGY

A. ANATOMY

Blood is the “river of life” that surges within us. It transport every blood that must be carried from one place to another within the body --- nutrient, waste (headed for elimination from the body) and body heat through blood vessels. It is our body’s major fluid, pumped by the heart. It continuously circulates through the blood vessels carrying the vital elements to every part of the body. Blood is made of: •

A liquid component – plasma

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Cellular components – erythrocytes, leukocytes and thrombocytes suspended in the plasma.

Plasma

Plasma is clear, straw-colored fluid that consists mainly of the proteins, albumin, globulin and fibrinogen held in aqueous suspension. Plasma’s fluid characteristics, including its osmotic pressure, viscosity and suspension qualities, depends on its protein component. Other components in plasma include glucose, lipids, amino acids, electrolytes, pigments hormones, oxygen and carbon dioxide. These components regulate acid-base balance and immune responses as well as carry nutrients to tissues and help to mediate coagulation.

Don’t forget to digest this bit of info. Important products of metabolism that circulate in plasma include urea, uric acid, creatinine and lactic acid. Red Blood Cells (Erythrocytes) RBC in adults are usually produced in the bone marrow. In the fetus, the liver and spleen also participate in RBC production. The RBC production process is called eryhtropoiesis. RBC’s transport oxygen to body tissues and carbon dioxide away from them. Hemoglobin, an oxygen-carrying substance, gives RBC this ability. Erythrocyte formation begins with a precursor, called a stem cell. The stem cell eventually develops into an RBC. Development requires Vit B12, folic acid, and minerals, such as copper, cobalt and especially iron. White Blood Cells WBC’s protect the body against harmful bacteria and infection. They’re classified in one of two ways, as: •

Granular leukocytes (granulocytes), such as neutrophils, eosinophils and basophils.

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Nongranular leukocytes, such as monocytes and lymphocytes.

Most WBC’s are produced in bone marrow. Lymphocytes complete their maturation in the lymph nodes.

 Types of granulocytes include the following: •

Neutrophils, the predominant form of granulocyte, make-up about 60% of WBC’s. They surround and digest invading organisms and other foreign matter by phagocytosis.

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Eosinophils, minor granulocytes, defend against parasites, participate in allergic reactions, and fight lung and skin infections.

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Basophils, also minor granulocytes, release histamine into the blood and participate in delayed allergic reactions. They also contain heparin, an anticoagulant.

 Types of nongranulocytes leukocytes include the following: •

Monocytes, along with neutrophils, devour invading organisms by phagcytosis. They also migrate to tissues where they develop into cells called macrophages that participate in immunity.

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Lymphocytes occur mostly in two forms: B cells and T cells. B cells produce antibodies. While T cells regulate cell-mediated immunity.

Platelets Platelets are small (2-4 microns in diameter), colorless, disk-shaped cytoplasmic cells split from cells in bone marrow. They have a life span of 7-10 days. Platelets perform 3 vital functions to help minimize blood loss: •

They help constrict damaged blood vessels.

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They perform hemostatic plugs, in injured blood vessels by becoming swollen, spiky, sticky and secretory.

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They provide substances that accelerate blood clotting, such as factors III and XIII and platelet.

Hematopoiesis (blood cell formation), occurs in red bone marrow, or myeloid tissue. In adults, this tissue is found chiefly in the flat bones of the skull and pelvis, the ribs, sternum, and proximal epiphyses of the humerus and femur. All the formed elements arise from a common type of stem cell, the hemocytoblast which resides in the red bone marrow. The population of stem cells renews itself by mitosis. Some of these cells become lymphoid stem cells, which then develop into two classes of lymphocytes that function in the immune response. All other blood cells differentiate from myeloid stem cells, also derived from the stem cells. The rate of erythrocyte production is controlled by a hormone called erythropoietin. Normally, a small amount of erythropoietin circulates in the blood at all times, and red blood cells are formed at a fairly constant rate. Although the liver produces some, the kidneys play the major role in this hormone. When blood levels of oxygen begin to decline for any reason, the kidneys step up their release of erythropoietin. It is not the relative number of RBCs in the blood that controls RBC production that controls RBC production. Control is based on their ability to transport enough oxygen to meet the body’s demands. Like erythrocyte production, the formation of leukocytes and platelets is stimulated by hormones. These colony-stimulating factors (CSFs) interleukins not only prompt red bone marrow to turn out leukocytes, but also enhance the ability of mature leukocytes to protect the body. The production of platelets is accelerated by the hormone thrombopoietin, but little is known about the regulation of platelet format.