ABSTRACT: This case analysis is centered on a patient who has been diagnosed with pernicious anemia. For the past month, the patient has been suffering from malaise, shortness of breath, fatigue, sadness, loss of appetite, nausea, and numbness of the hands and feet. She went to her doctor and her condition necessitated the completion of various tests. Antibodies to parietal cells, irregular reticulocyte count, decreased arterial oxygen, a lower hematocrit percentage, and vitamin B12 insufficiency were discovered. Her diagnosis was based on a blood slide that revealed macrocytic red blood cells. The antibodies damaged the parietal cells in the gastric mucosa at the fundus of the stomach.


Cardiovascular System

The human body comprises several body systems that ensure the normal functioning of physiological processes. The cardiovascular system consists of the heart, blood, and blood vessels. The system ensures a continuous supply of blood throughout the body. Roles of this system entail the transportation of nutrients such as oxygen, water, glucose, ions, minerals, and heat to all parts of the body for proper functioning and energy. It facilitates the removal of waste and byproducts such as nitrates, urea, and carbon(IV)oxide, which are toxic if they remain in the body. Hormone transport, control, and regulation are all accomplished through blood arteries and bodily fluids. White blood cells are the body’s defense system against infections, and they are found in the blood.

Digestive System

The digestive system comprises the gastrointestinal tract, liver, pancreas, and gallbladder connected with the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus. Food that includes carbohydrates, lipids, vitamins, and proteins is broken down into components that can be absorbed into the bloodstream by enzymes secreted by the secretory cells. The enzymes are amylase secreted by salivary glands for carbohydrates, the proteolytic enzyme produced in the pancreas breaks down proteins, and lipase produced in the pancreas for fats breakdown. Absorbed nutrients are utilized for energy, growth, and repair by the body.

Immune System

The immune system includes white blood cells, antibodies, the complement system, the lymphatic system, the spleen, the thymus, and the bone marrow. They protect the body by actively fighting infections from foreign invaders and pathogenic microorganisms such as bacteria, viruses, fungi, parasites, and toxins. The human body relies on the innate and adaptive defense system, which acts cooperatively and independently to resist diseases. The innate defense system responds immediately against foreign substances. It makes up the first and second line of defense. The adaptive defense system is more equipped to attack particular foreign substances and takes more time to mount responses.


Autoimmune antibodies

The gastric mucosa is lined by parietal cells responsible for producing intrinsic factors and hydrochloric acid. Autoimmune antibodies work against the hydrogen/potassium ATPase pump by triggering the CD4 T cell lymphocytes, which cause immune destruction of the parietal cells (Rodriguez, 2021). Destruction of the gastric parietal cells leads to losing intrinsic factors and the absence of HCL secretion. Intrinsic factor deficiency causes pernicious anemia, while a neutralizing intrinsic factor antibody prevents cobalamin absorption (Toh, 2017). Due to acid loss, iron deficiency anemia occurs before cobalamin-deficient pernicious anemia. HCL aids protein digestion by converting pepsinogen to pepsin and protects the body from infection by killing microorganisms.


Antibodies are immunoglobulins, which are a type of blood protein called gamma globulin. In response to an antigen, activated B cells or plasma cells produce these proteins. Antibodies are divided into five categories: IgA, IgM, IgD, IgE, and IgG The basic structure of IgD, IgG, IgE, and IgM is made up of four looping polypeptide chains linked by disulfide bonds. The functions of antibodies include activating the complement system, neutralizing pathogenic microorganisms through phagocytosis, and binding to antigens to cause agglutination when the body is exposed to foreign cells (Tortora& Derrickson, 2018). The antibody IgM is released in the primary response to infections then the plasma cells begin to secrete IgG.

Intrinsic Factor

Intrinsic factor is a glycoprotein secreted by the stomach’s gastric parietal cells that attach to cobalamin and allow it to enter the terminal ileum for absorption (Rodriguez, 2021). Orally consumed vitamin B12 cannot be absorbed without intrinsic factors, and erythrocytes cannot be formed. Production eventually declines, leading to low red blood cell counts (Suzanne & Brenda, 2004). Monthly vitamin B12 intramuscular injections to replace the absence of the intrinsic factor. Oral supplementations of vitamin B12 2mg/day or fortified soy milk are also effective, especially if the patient is a vegetarian. The therapy alleviates the symptoms and returns the reticulocytes to normal levels. Vitamin B12 therapy must be continued indefinitely to prevent the recurrence of pernicious anemia.

Without enough vitamin B12, the body is unable to correctly synthesis DNA, resulting in nuclear division inhibition. Because the cells divide while their nuclei are still immature, this has an impact on red blood cell production. Megaloblasts are huge red blood cells that are primarily destroyed in the bone marrow and never leave the body. Some megaloblasts mature into macrocytes, massive red blood cells with an abnormal morphology that enter the circulation but perform poorly. Hematopoiesis is disrupted when DNA synthesis is altered, and tissues such as gastrointestinal cells are rapidly renewed. The process of generating all of the blood’s cellular components and blood plasma is known as hematopoiesis.

Oxygen Carrying Capacity

Red blood cells are small in diameter, biconcave shaped, and flattened disc with a depressed center. They contain hemoglobin, a protein that makes the cells bind to oxygen reversibly for easy transport across the body and promoting changes in the red blood cell’s shape. Hemoglobin comprises the protein globin that binds to the red heme pigment. Each heme group bears an iron atom at its center, while the globin has four polypeptide chains: two alpha and two betas, all bound to the ring-like heme group (Tortora& Derrickson, 2018). Oxygen binds to the iron portion of the heme group for transport by Hb. Low reticulocyte count will cause decreased oxygen levels available in the body hence causing low partial pressure oxygen.

The patient has low oxygen levels caused by abnormal macrocytic erythrocytes. Hypoxia is inadequate oxygen in the body tissues will stimulate the kidneys to accelerate their release of erythropoietin. Erythropoietin is a glycoprotein hormone produced by the kidneys and liver that stimulates the production of red blood cell formation. The negative feedback mechanism of homeostasis is used to increase the production levels of red blood cells. Decreased number of RBCs causes a low oxygen-carrying capacity detected by chemoreceptors (Toh, 2017). s. Kidneys and the liver are stimulated to release EPO hormone into the bloodstream. The hormone acts on the bone marrow to increase RBCs’ production, hence increasing oxygen-carrying levels.

Blood Volume

Hematocrit, also called packed red cell volume, is the calculated proportion of red blood cells in an individual’s blood. Normal ranges of hematocrit in females are 37-47%, while in males, it is 45-54%. The test is obtained as part of the complete blood count (CBC) laboratory test. Low hematocrit levels indicate that there is a fewer number of red blood cells in the body. The lifespan of red blood cells is 120 days after production, but the macrocytic cells are rapidly destroyed(Tortora& Derrickson, 2018). Inadequate vitamin B12, iron, and folate cause a decreased hematocrit percentage. Low levels of hematocrit exacerbate the symptoms of anemia. Patients with anemia should have laboratory test such as complete blood counts measured to establish the type of anemia whether its macrocytic or microcytic.

In conclusion, pernicious anemia compromises the circulatory, digestive and immune systems. Destruction of parietal cells by the autoimmune antibodies causes loss of intrinsic factors and the absence of hydrochloric acid. The acid is responsible for destroying harmful substances digested; hence its absence increases susceptibility to infections and digestion of proteins. Lack of intrinsic factors makes the body unable to absorb vitaminB12. Therefore, the patient should be educated on the importance of compliance with vitamin B12 therapy and dietary habits. Help the patients identify diets with adequate vitamin B12 such as meat, liver, fish, and chicken. In cases where they are vegetarians, encourage them to take vitamin supplements.


Rodriguez, N. M., & Shackelford, K. (2021). Pernicious anemia. StatPearls [Internet].

Suzanne, S. C., & Brenda, B. G. (2004). Brunner and Suddharths Medical-Surgical Nursing.

Toh, B. H. (2017). Pathophysiology and laboratory diagnosis of pernicious anemia. Immunologic research, 65(1), 326-330.

Tortora, G. J., & Derrickson, B. H. (2018). Principles of anatomy and physiology. John Wiley & Sons.

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