Week 2 Discussion 1: Discussion-Based Case

Value: 100 points

Due: To facilitate scholarly discourse, create your initial post by Day 3, and reply to at least two of your classmates, on two separate days, by Day 7.

Gradebook Category: Discussions

Introduction

Each week you will be working within a team that is assigned to a specific topic area. Each topic area is comprised of a group of questions related to that topic. Some weeks you will be responsible for posting an initial reply to only one of the questions within your team, and some weeks you will be responsible for posting a reply to all of the questions within your team. You will be on the same team every week of the course.

In weeks where you are responsible for posting an initial reply to only one of the questions, you will be assigned a number to reply to (your number will remain the same throughout the course). For example, if you are a student on Team A, and your assigned question is 3, you will answer question A-3 on the weeks where only one question is required.

Instructions

Review the Case Study Discussion Scenario. For this discussion you will respond to ALL of the questions within either Part A, B, or C based the team you have been assigned.

Case Study Discussion Scenario

Mr. K. B. is age 81 and has had gastritis with severe vomiting for three days. He has a history of heart problems and is presently feeling dizzy and lethargic. His eyes appear sunken, his mouth is dry, he walks unsteadily, and he complains of muscle aching, particularly in the abdomen. He is thirsty but is unable to retain food or fluid. A neighbor has brought Mr. K. B. to the hospital, where examination shows that his blood pressure is low, and his pulse and respirations are rapid. Laboratory tests demonstrate elevated hematocrit, hypernatremia, decreased serum bicarbonate, serum pH 7.35, and urine of high specific gravity (highly concentrated).

Initial Post

It is understood that thoughtful responses to your topic question(s) will take some time and thought. Please organize your thoughts before creating your initial post.

Based on your assigned team, create an initial post by answering all questions for your assigned part, making sure to address all components of all questions.

By Day 3, post your initial response to your assigned part of the case study as a reply to the appropriate discussion thread. Please be sure to number the questions addressed and include all components of each question in your response. Each initial response must have a reference, including at least 2 scholarly references other than your text or course materials. Your post should be limited to 500 to 750 words and comprehensively address the questions posed.

Team A-Part 1: Day 1 – Early Stage

Week 2 Discussion Team A Worksheet (Word)

Initially, Mr. K .B. lost water, sodium in the mucus content, and hydrogen and chloride ions in the hydrochloric acid portion of the gastric secretions. Alkalosis develops for two reasons; the first being the direct loss of hydrogen ions and the second being the effects of chloride ion loss. When chloride ion is lost in the gastric secretions, it is replaced by chloride from the serum (see Figure 2.9 in your textbook). To maintain equal numbers of cations and anions in the serum, chloride ion and bicarbonate ion can exchange places when needed. Therefore, more bicarbonate ions shift into the serum from storage sites in the erythrocytes to replace the lost chloride ions. More bicarbonate ions in tserum raise serum pH, and the result is hyperchloremic alkalosis.

1. Describe the locations of intracellular and extracellular fluids. Which makes up a higher proportion of body fluid?
2. Which cell compartments are likely to be affected in this case by early fluid loss?
3. Explain how a loss of sodium ions contributes to dehydration. Why does this dehydration affect cell function?
4. Describe the early signs of dehydration in Mr. K. B.
5. What serum pH could be expected in Mr. K. B. after his early vomiting?
6. Describe the compensations for the losses of fluid and electrolytes that should be occurring in Mr. K. B.
7. How does the proportion of fluid in the body (from the previous question) change with age?
8. Explain why Mr. K .B. may not be able to compensate for losses as well as a younger adult.

Team B-Part 2: Days 2 to 3 – Middle Stage

Week 2 Discussion Team B Worksheet (Word)

As Mr. K. B. continues to vomit and is still unable to eat or drink any significant amounts, loss of the duodenal contents, which include intestinal, pancreatic, and biliary secretions, occurs. No digestion and absorption of any nutrients occurs. Losses at this stage include water, sodium ions, potassium ions, and bicarbonate ions. Also, intake of glucose and other nutrients is minimal. Mr. K. B. shows elevated serum sodium levels.

1. What is the normal function of sodium in the body?
2. Explain why serum sodium levels appear to be high in this case.
3. Explain how high serum sodium levels might affect the intracellular fluid and extracellular fluid volumes.
4. Using your knowledge of normal physiology, explain how continued fluid loss is likely to affect the following:
   1. Blood volume
   2. Cell function
   3. Kidney function
5. State the primary location (compartment) of potassium.
6. How are sodium and potassium levels controlled in the body?
7. Given Mr. K. B.’s history, why might potassium imbalance have more serious effects on him?
8. State the normal range of pH for the following:
   1. Blood
   2. Urine

Team C-Part 3: Day 3 Admission to the Hospital – Advanced Stage

Week 2 Discussion Team C Worksheet (Word)

After a prolonged period of vomiting, metabolic acidosis develops. This change results from a number of factors:

1. Loss of bicarbonate ions in duodenal secretions
2. Lack of nutrients, leading to catabolism of stored fats and protein with production of excessive amounts of ketoacids
3. Dehydration and decreased blood volume, leading to decreased excretion of acids by the kidney
4. Decreased blood volume, leading to decreased tissue perfusion, less oxygen to cells, and increased anaerobic metabolism with increased lactic acid
5. Increased muscle activity and stress, leading to increased metabolic acid production

These factors lead to an increased amount of acids in the blood, which bind with bicarbonate buffer result in decreased serum bicarbonate and decreased serum pH or metabolic acidosis.

1. List several reasons why Mr. K. B. is lethargic and weak.
2. Predict the serum level of carbon dioxide or carbonic acid in this case. Explain your prediction.
3. If Mr. K. B. continues to lose body fluid, why might serum pH decrease below 7.35?
4. If serum pH drops below 7.35, what signs would be observed in Mr. K. B.?
5. If serum pH drops below 7.35, would this be considered compensated or decompensated? Explain the pathophysiology that contributes to this.
6. What are the very slow, shallow respirations that occur with metabolic acidosis called? How are they likely to affect the following?
   1. PCO2
   2. Serum pH
7. Describe the effect of acidosis on serum potassium levels.
8. Mr. K. B. will be given replacement fluid therapy. Why is it important that sodium and potassium be given as well as water?

Reply Posts

Please reply to two peers that posted an initial response from a different team than your own (for example, if you initially posted to Team A Part 1, you will create a reply post to one peer from Team B Part 2 and a reply post to one peer from Team C Part 3). Each reply must use at least one scholarly reference other than your textbook. After reading a selection of your peers’ posts:

• Consider the pathophysiology that is occurring in each stage; how might that present in Mr. K. B.? Remembering the difference between signs and symptoms from Week 1, identify three signs and three symptoms he might be exhibiting in that stage. Explain why these would develop in each stage, and support your answers with evidence.
• Finally, identify which section of the SOAP note each would be documented in.

Please refer to the Grading Rubric for details on how this activity will be graded.

Posting to the Discussion Forum

1. Select the appropriate Thread.
2. Select Reply.
3. Create your post.
4. Select Post to Forum.

1. What is the normal function of sodium in the body?

Sodium is an important cation that helps to maintain extracellular fluid volume by altering osmotic pressure. (Hubert & VanMeter, 2018, p. 21) It is the largest number of solutes that exists in extracellular fluid. Sodium ions has a role in the “conduction of nerve impulses and in muscle contraction” (p. 22). When levels of sodium in the blood is out of the normal range of 135-145 mEq/liter, changes to the balance of fluid volume, nerve conduction, and muscle contraction can occur resulting in various symptoms experienced by the individual (p. 23).

2. Explain why serum sodium levels appear to be high in this case.

Mr. K.B is dehydrated as evidenced by his persistent vomiting and anorexia. Dehydration occurs when the loss of fluids from the body exceeds the amount that is being replaced (Taylor & Jones, 2021). When the gastric emptying involves both water and ions including sodium, it is considered to be an isotonic water loss. In this case, however, Mr. K. B’s sodium level appears high, which could be due to a hypertonic dehydration in which the amount of water loss exceeds the amount of sodium lost. According to Taylor & Jones (2021), pure water can be lost through the skin, kidneys, and lungs. Not only is Mr. K.B. losing sodium through emesis, pure water loss is also occurring with his rapid respirations.

3. Explain how high serum sodium levels might affect the intracellular fluid and extracellular fluid volumes.

Hypernatremia creates an osmotic shift to occur, moving water out of the cells (Sterns, 2020). It occurs due to the increase of intracellular fluid osmotic pressure, leading to the movement of fluid into the interstitial place (Hubert & VanMeter, 2018, p. 19).

4. Using your knowledge of normal physiology, explain how continued fluid loss is likely to affect the following:
   1. Blood volume

The loss of water results in a lower blood volume and subsequently, hypotension, and hypovolemic shock (Hubert & VanMeter, p. 82). Because blood is 55% plasma, of which is 90% water, the loss of water can drastically reduce the overall blood volume (Informed Health, 2019).

4. 2. Cell function

Fluid loss in the case of vomitus and dehydration results in a shift of fluid into the digestive tract in order to replace the lost secretions (Hubert & VanMeter, 2018, p. 20). Cellular function is impaired as metabolic dysfunction occurs from a lack of blood volume and nutrients needed for normal cell function and growth (Schlichte et al., 2021).

4. 3. Kidney function

The kidney is responsible for regulating the balance of salt and water. In the case of hypovolemia, renal hypoperfusion can occur leading to kidney injury and or failure (Feehally & Khosravi, 2015). The article also notes that the risk of kidney injury from dehydration is increased in older populations.

5. State the primary location (compartment) of potassium.

Potassium is a major cation that is located in the intracellular compartment (Hubert & VanMeter, 2018, p. 24).

6. How are sodium and potassium levels controlled in the body?

Sodium and potassium levels are controlled through a balance across the sodium-potassium pump (Hubert & VanMeter, 2018, p.21). Active transport of the ions occurs across the concentration gradient in order to achieve homeostasis (Udensi & Tchounwou, 2017).

7. Given Mr. K. B.’s history, why might potassium imbalance have more serious effects on him?

Abnormal levels of potassium can cause changes in membrane potential of cardiac muscles and lead to detrimental cardiac conditions (Toto, 2017). Arrythmias from dyskalemia can ultimately lead to a cardiac arrest. In Mr. K.B.’s case, his kidneys are already impaired due to dehydration, which could lead further to hyperkalemia. Considering that Mr. K.B. already suffers from heart disease, his risk factors for a fatal arrythmia is increased.

8. State the normal range of pH for the following:
   1. Blood

The normal range for the pH of blood is between 7.35 and 7.45 (Theodore, 2020). It is measured using electrodes and converted from voltage to pH.

b.  Urine

The normal range of pH of urine is between 4.5 and 8, which measures the concentration of urine hydrogen ion (Wald, 2021).

References

Feehally, J. & Khosravi, M. (2015). Effects of acute and chronic hypohydration on kidney health and function. Nutrition Reviews, 73(2), 110-119. https://doi.org/10.1093/nutrit/nuv046

 

Hubert, R. J., & VanMeter, K. C. (2018). Gould’s Pathophysiology for the Health Professions (6^th edition). Elsevier, Inc.

 

Informed Health. (2019). What does blood do? Institute for quality and efficiency in health care. https://www.ncbi.nlm.nih.gov/books/NBK279392/

 

Schlichte, M., Jahne, M., & Georgi, T. (2021). Dehydration — Isotonic, hypotonic, and hypertonic fluid disorders. Lecturio Medical Online Library. https://www.lecturio.com/magazine/dehydration/#overview

 

Stern, R. (2020). General principles of disorders of water balance (hyponatremia and hypernatremia) and sodium balance (hypovolemia and edema). UpToDate. https://www.uptodate.com/contents/general-principles-of-disorders-of-water-balance-hyponatremia-and-hypernatremia-and-sodium-balance-hypovolemia-and-edema

 

Taylor, K., & Jones, E.B. (2021). Adult Dehydration. StatPearls Publishing.https://www.ncbi.nlm.nih.gov/books/NBK555956/

 

Toto, R. (2017). Serum potassium and cardiovascular outcomes: The highs and the lows. Clin J Am Soc Nephrol, 12(2), 220-221. https://doi.org/10.2215%2FCJN.00030117

 

Udensi, U. K., Tchounwou, P. B. (2017). Potassium Homeostasis, Oxidative Stress, and Human Disease. Int J Clin Exp Physiol, 4(3), 111-122. https://doi.org/10.4103/ijcep.ijcep_43_17

 

Wald, R. (2021). Urinalysis in the diagnosis of kidney disease. UpToDate. https://www.uptodate.com/contents/urinalysis-in-the-diagnosis-of-kidney-disease