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


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.


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