MN551 Pathophysiology Case Study

Running head: PATHOPHYSIOLOGY CASE STUDY 1

PATHOPHYSIOLOGY CASE STUDY 6

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Tissue ischemia is a condition caused by a reduced blood flow into a tissue which leads the reduction of oxygen and nutrients to that tissue. The lack of blood and oxygen supply leads to the dysfunction of the particular tissue. It can also impair the removal of waste products such as lactic acid from that tissue. This increases the risk of tissue death. One of the reasons why Maria will have tissue ischemia is high blood pressure. The high blood pressure is associated with thickening of the heart muscles. This leads to impairment of heart relaxation during heartbeats. It contributes to the insufficient supply of blood to the tissues resulting in tissue ischemia. (Reivich, Martin, 2013).

Another reason why Mary is likely to have tissue ischemia is due to her enlarged heart. An enlarged heart may be as a result of the walls of the ventricles of the heart becoming thin and stretched. This declines the heart pumping abilities meaning that it cannot supply adequate blood to body tissues. It could also result from the thickening of the left ventricle which hinders the heart pumping abilities. This can contribute to congestive heart failures characterized by a tired feeling, as it is the case with Mary, shortening of breath, and palpitations. It leads to insufficient supply of blood into the tissues and hence tissue ischemia. It may also lead to hypoxia, a situation where the body tissues do not get enough oxygen to meet the body needs, characterized by shortening of breath and changes in skin color as well as wheezing. Oxygen is transported to the tissues by the blood flow. Hence, a reduction in blood flow in the tissues, tissue ischemia, would result to a reduction in oxygen supply in the tissues, hypoxia. (Reivich, Martin, 2013).

There are some reversible changes that occur in tissue cells when they are hypoxic. These changes may be reversed to normal cell operations when the normal oxygen supply is resumed. One of the early changes to the tissues cells that are hypoxic is the cellular energy production with the cells reverting to anaerobic metabolism due to insufficient supply of oxygen. Oxygen and other nutrients enter the cell through the cell membrane. Hypoxia would result in an inadequate flow of nutrients and oxygen into the cell. Due to the insufficient flow of oxygen, the cells rely on anaerobic metabolic energy production pathways. There is a much-reduced mitochondria activity due to the supply of oxygen which leads to rapid utilization of the ATP stores. Lactic acid and nitric oxide are the two end products which result in the lowering of the PH of both the cell and blood fluids. (In Madonna, 2015).

Another reversible change that occurs in hypoxic tissue cells is the disruption of the cellular membrane and hence electrolyte disturbances. Due to insufficient supply of ATP, the plasma membrane of the cell is unable to maintain the normal ionic gradients across the cell membrane. This leads to a rapid efflux of potassium ions from the cell and an influx of sodium ions and water into the cell through active transport. The movement of sodium and water into the cell may lead to swelling and distortion of the cell as the cytoplasmic membranes become increasingly permeable. The conduction of electronic impulses would be affected as it requires an intact cell membrane. This may limit the movement of muscles and thus affect the normal contraction of cells which could be reversed if the normal supply of oxygen is restored. (In Madonna, 2015).

In the case of Maria, there is an insufficient supply of oxygen in the tissue cells. Due to the insufficient flow of oxygen and other nutrients into the cells, the cells have resorted to anaerobic metabolic pathways for energy production. The aerobic metabolic pathways are more effective in energy production compared to the anaerobic metabolic pathways. Maria is faced with a situation where the tissues cells do not largely utilize mitochondria, which utilizes oxygen, for the production of energy needed by body organs including the heart. As a result, the heart is less effective in its functioning due to lack of enough ATP. This results in the heart pumping sufficient blood to some body organs, such as the brain, but not other organs, such as the feet and arms. This explains why Maria has been feeling cold in her hands and feet meaning that, these organs are not receiving enough blood supply. (In Bärtsch, & In Swenson, 2014).

Another specific cellular adaptation in the case of Maria is the electronic disturbance resulting from the disruption of the cellular membrane. Due to the insufficient production of energy, the body is unable to maintain the normal ionic gradients across the cell membranes. This has led to a high movement of sodium ions and water into the body cells as well as an efflux of potassium ions from the body cells. The increased influx of water into the cells has resulted in cell distortion and swelling of cells in some tissues. This could explain why Maria has edema around her ankles and legs. It is as a result of the cells around these areas being swollen and distorted. (In Bärtsch, & In Swenson, 2014).

The most likely reason why Maria’s heart has been enlarged is the high blood pressure. A high blood pressure causes the heart to pump harder in order for blood to be delivered to all organs of the body. The left ventricle is responsible for pumping blood to other body organs.

High blood pressure causes the left ventricle to enlarge while the muscles weaken. As the ventricles enlarge, the heart also enlarges. This is the main reason for Maria’s heart enlargement. The fact that Maria is overweight is a risk factor for the high blood pressure and hence the heart enlargement. (Vordermark, 2013).

The reason Maria’s heart enlargement does not have the same cardiac strength and endurance as a well-trained athlete is that, unlike the enlarged heart of a well-trained athlete,

Maria’s heart enlargement is as a result of the heart being overworked due to high blood pressure. This leads to the thickening of the left ventricle of the heart while the ventricle muscles are weakened. For a well-trained athlete, the increase in heart cavity dimension or wall thickness is accompanied by strengthening of the wall muscles. Heart enlargement in athletes is an adaptation to dynamic training which increases the cardiac output. The enlargement is also associated with an increase in the stroke volume systolic blood pressure, and the oxygen consumption. The heart of an athlete adapts to the high needs of oxygen and energy by the tissue cells of an athlete. Depending on the kind of exercise, the heart enlargement may be associated with an increase in volume load or a pressure load of the left ventricle. An endurance exercise would produce a volume load on the left ventricle while a strength exercise would produce a pressure load. In the case of Maria, heart enlargement is a result of the heart being overworked rather than an adaptation to body needs. (Vordermark, 2013).

References

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In Bärtsch, P., & In Swenson, E. R. (2014). High altitude: Human adaptation to hypoxia.

In Madonna, R. (2015). New developments in myocardial ischemia research.

Reivich, Martin. (2013). Tissue Hypoxia and Ischemia. Springer Verlag.

Vordermark, D. (2013). Hypoxia: Causes, types and management. Hauppauge, N.Y: Nova Science.

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