Part 1: Acid-Base—questions 1-2 [8 POINTS]
1. Christopher is a Connecticut resident who has come to Colorado for a vacation. On the day after his arrival, Chris decides to climb Mt. Evans, a 14,000-ft. peak in the Rocky Mountains. Which is Chris more likely to experience, respiratory acidosis or alkalosis? Why? How do the kidneys compensate for this? [3 POINTS]
2.
A. Scott has the flu and has been having diarrhea. What effect would this diarrhea have on his plasma pH? What acid-base disorder is most likely given this information? Explain your answers. How would his respiratory rate be affected by this pH disturbance? [3 POINTS]
B. Would Scott present with hyperkalemia (↑ plasma K+) or hypokalemia (↓ plasma K+)? Why? [2 POINTS]
Part 2: questions 3-4. [15 POINTS]
Mr. Crabtree, a 52-year-old male, was on his way to work during a heavy rainstorm when he lost control of his car and crossed into oncoming traffic where he collided head-on with a small delivery truck. Witnesses accessed the 911 emergency medical response system, and paramedics arrived quickly. The driver of the truck suffered only minor cuts and scrapes, but Mr. Crabtree was having difficulty breathing and complained of severe chest pain. Transport time to the nearest trauma center was less than two minutes, so the emergency personnel elected to “scoop and haul.” A large bruise on his chest indicated that Mr. Crabtree had experienced blunt trauma from the impact of the steering wheel after the airbag failed to deploy.
Mr. Crabtree presented in the ER with blurred vision, dizziness, headache, nausea, muscle weakness, hypoventilation, and a feeling of mental confusion. A chest X ray revealed bilateral fractures in the fourth, fifth, and six ribs along with a suspected hemothorax. An ECG revealed signs of ventricular arrhythmias. The values following values were taken from the results of an arterial blood gas (ABG) and urinalysis (UA).
Arterial Blood Gas (ABG) High or Low?
pH: 7.0
PCO2: 62 mmHg
Bicarbonate: 29 mEq/L
Urinalysis (UA) High or Low?
pH: 4.0
3.
A. Identify if the results listed above are higher or lower than normal. What are the approximate normal ranges for the results listed above? [2 POINTS]
B. Mr. Crabtree’s PCO2 is abnormal. Under normal conditions, what’s the PRIMARY mechanism that the body uses to regulate PCO2 level in blood? Why is this not working for this patient? [2 POINTS]
C. Describe how the PCO2 and pH in Mr. Crabtree’s blood are related in this case. [2 POINT]
D. Describe how the bicarbonate in Mr. Crabtree’s blood is related to the pH in his urine. [2 POINTS]
E. What is the acid-base disturbance in this case? Are there any compensatory mechanisms at play? If so, what are they and how do you know? [2 POINTS]
4. Although it wasn’t necessary to calculate in this case, what is an anion gap and what acid-base disturbance is associated with a high anion gap? Describe TWO CONDITIONS associated with a high anion-gap? Why does each condition cause a high anion gap (i.e explain why there is an anion gap). [5 POINTS]
Part 3: Questions 5-9 [21 POINTS]
Part I – Food poisoned me
One evening during a recent trip to Indonesia, Dr. Fugu Spork sat down to a meal of puffer fish and rice, also called “Fugu.” Because Dr, Spork and this dish share a name, he couldn’t resist ordering it. Within an hour of returning to his hotel room, Dr. Spork felt numbness in his lips and tongue, which quickly spread to his face and neck. Before he could call the front desk, he began to feel pains in his stomach, throat, and mouth. He then developed feelings of severe nausea and eventually severe vomiting. The vomit was positive for blood as well.
Fearing that he had eaten some “bad fish” for dinner, Dr. Spork called the local hospital to describe his condition. The numbness in his lips and face made it almost impossible to communicate, but the ER nurse was able to get part of the address written down and an ambulance was dispatched. As Dr. Fugu Spork was rushed to the ER, his breathing became increasingly labored and he was showing signs that he could not protect his airway.
Part 2 – Numb, sweaty, and short of Breath…not love at first bite
Upon presenting to the ER, he was diaphoretic, exhibited significant motor dysfunction, paresthesias, nausea, an ascending paralysis starting in his legs and spreading to upper body, arms, face, and head. He also had problems with his breathing and was cyanotic and hypoventilating. Within 30 minutes of presenting in the ER, Dr. Spork developed bradycardia with hypotension. Atropine was administered in response to the bradycardia. Intravenous hydration, gastric lavage, and activated charcoal followed a presumptive diagnosis of tetrodotoxin poisoning. Five hours after treatment, the following vital signs were noted:
• BP: 125/79 mmHg with HR: 78 bpm
• Oxygen saturation: 97% with Respiration rate: 12 on ventilator in ICU
Blood Gas Analysis (prior to intubation) Biochemistry
pH 7.217 Total bilirubin 0.7 mg/dl
PaCO2 54.3 mmHg AST 35 U/L
PaO2 83 mmHg ALT 32 U/L
HCO3- 32.1 mEq/L Lactate 3.1 mmol/L
Creatine kinase 123 U/L
CBC BUN 22.3 mg/dl
WBC 7730 /mm3 Cr 0.7 mg/dl
RBC 4.21×104 /mm3 Na+ 154 mEq/L
Hct 38.1 % K+ 5.6 mEq/L
Hgb 12.9 g/dl Cl- 116 mEq/L
Plt 20.0×104 /mm3 Ca2+ 7.8 mg/dl
Blood glucose 230 mg/dl
Phosphorus 2.1 mg/dL Mg2+ 1.2
•
•
After discussing Dr. Spork’s case with his physician, you learned that he had probably been the victim of pufferfish poisoning. Normal lab values are listed below.
Questions
5. Interpret Dr. Spork’s ABG findings. What is the presenting acid-base disturbance? Is there any compensation? Do these lab findings make sense in light of the clinical picture in the Emergency Department? [5 POINTS]
6. Describe the relevance of an elevated Na+ level in this patient. What does the serum sodium tell you about his water balance within the body? Explain your answer. [4 POINTS]
7. It is noted that the patient has an elevated K+ level as well as a low Ca2+ level in his blood. How would each of these abnormalities affect his cardiac function? Explain. [4 POINTS]
8. How would the endocrine system respond to low Ca2+ levels in the blood? What hormone would be secreted and how would that hormone raise blood Ca2+ levels? Be specific. [4 POINTS]
9. Explain how tetrodotoxin causes this patient’s hypotension and hypoventilation. [4 POINTS]
Part 4: Questions 10-11 [38 POINTS]
10. Describe the three processes involved in urine formation. Be detailed about each process, where each process occurs, and the role each process plays in overall urine formation. [6 POINTS]
11.
A. Describe BOTH the anatomy AND physiology of the nephron (i.e discuss all five (5) main parts of the nephron/collecting system). Be specific. [10 POINTS]
B. Describe how the two limbs of the loop of Henle differ in function and permeability (i.e ascending vs. descending limbs). Be specific. Explain how this contributes to urine formation. [4 POINTS]
C. What is meant by “renal multiplier” and “renal countercurrent” exchanger?” Be specific about what each one represents. [4 POINTS]
D. Discuss TWO major hormones involved in urine formation. Describe the effects of each hormone, the portion of nephron/collection system that each acts, and how both are regulated. [6 POINTS]
E. Discuss the Renin-angiotensin-aldosterone system (R-A-A-S). How does this pathway work and how are the various body systems that we learned about this semester (i.e endocrine, cardiovascular, respiratory, GI, and urinary) involved in this pathway? [8 POINTS]
Part 5: questions 12-13 [20 POINTS]
Theodore (“Teddy”) is sitting in his athletic training suite feeling sorry for himself. He moved from Southern California to play soccer at Michigan State University (MSU) as a highly recruited player. All was well until he got sick with a miserable cold. He soon recovered, but now he finds himself with a lingering dry cough and difficulty catching his breath any time he exerts himself. He also notices it has gotten worse as the weather has become colder. To make things worse, Teddy feels, and looks, like he’s out of shape, so his coach has been criticizing him for “dogging it.”
A few days later, Teddy relays his story to Al, the head athletic trainer at MSU. “I’m thinking my cold is coming back, or something else is wrong with me. When I’m just hanging out, like now, I feel fine. But as soon as I start to run, I get winded and can’t stop coughing.” Al listens to Teddy’s breathing sounds with his stethoscope but hears nothing abnormal. He tells Teddy to come back as soon as the symptoms return during soccer practice. Twenty minutes later, Teddy is back in the athletic training suite, audibly wheezing, coughing, and short of breath. The team physician, Dr. Gibson, happens to be there and performs a complete physical exam. He also does pulmonary function tests with Teddy using spirometry, including a forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). He instructs Teddy to take a maximal inhalation and then exhale as forcefully and maximally as possible into the spirometer.
Based on his findings, Dr. Gibson tells Teddy he thinks he is experiencing cold-induced bronchoconstriction, or cold-induced asthma, which is made worse by exertion. The doctor explains to Teddy that his recent upper respiratory infection probably inflamed his airways, making them hypersensitive and reactive to irritants, such as cold and physical exertion. When Teddy exercises in the cold, autumn afternoons of Michigan, his sensitive airways temporarily bronchoconstrict, causing the symptoms he is experiencing. Dr. Gibson prescribes two puffs of an albuterol inhaler, to be used 10 minutes before a bout of exercise in the cold.
12. When Teddy is experiencing an asthmatic attack, his forced vital capacity (FVC) is 53% of normal, and his FEV1 (Forced expiratory volume in 1 second) is 45% of normal. Explain these test results and what they represent in Teddy’s case. Do these results signify an obstructive process or a restrictive process? How do you know?. [4 POINTS]
13. Spirometry testing is routinely performed on patients with lung disease. Describe how the various lung volumes and respiratory capacities would be predicted to change (from normal) in a patient with a restrictive lung process (i.e pulmonary fibrosis) as well as a patient with an obstructive lung process (i.e asthma or COPD). Using the pathophysiology underlying restrictive and obstructive lung diseases, explain why you predicted each volume and/or capacity to increase, decrease, or stay the same in each type of lung disease. [16 points]
Part 6: question 14 [20 POINTS]
14.
A. In left-sided systolic congestive heart failure, the heart fails to contract sufficiently enough to pump blood throughout the body. Describe how failure of the heart to pump efficiently will impact the respiratory, urinary, cardiovascular, as well as endocrine systems? I want you to think about how everything fits together physiologically. [12 POINTS]
B. Describe the differences between alpha-1, alpha-2, beta-1, and beta-2 adrenergic receptors. What are the effects of stimulation of each type of receptor? Describe why certain beta-blockers, beta-agonists, alpha-blockers, and alpha-agonists are specifically chosen as a treatment for patients. For example: certain medications are not used in a patient with asthma or COPD when trying to treat heart failure and hypertension. Explain why this is the case. Be concise but specific in your responses . [8 POINTS]
Part 7: Question 15 [28 POINTS + 8 POINTS BONUS]
15. A 38yo caucasian male presents to the ER after a 2 week bender of heavy alcohol consumption. He admits to drinking 5 handles of whiskey in the past 2 days. He claims that he has started to vomit up blood and has lost 15 pounds in the last 2 weeks due to not having an appetite. He eats mainly Ho-Hos and Twinkies. He is experiencing epigastric abdominal pain and has significant melena. He also has ataxic gait, poor muscle coordination, and significant confusion. His skin and sclera have a yellow hue, he has moderate hepatomegaly, pitting edema in his legs, and significant abdominal ascites.
A. The patient is significantly dehydrated. Explain the physiological reason for this based on his history of heavy alcohol consumption. Alcohol specifically causes profound diuresis because causes what condition of the endocrine system? Which hormone is affected? Explain your answer. [4 POINTS]
B. Describe effects of chronic alcoholism on the GI system. What are THREE conditions that this patient needs to be evaluated for based on his history? Support your answers with supporting items from patient’s history. [6 POINTS]
C. The patient’s lab values are shown below. Interpret his lab values and vitals. Which values are high, low, and normal. For each result that is not within normal range, explain why it is high or low in this patient. [12 POINTS]
Blood Gas Analysis (prior to intubation) Biochemistry
pH 7.07 Total bilirubin 6.7 mg/dl
PaCO2 51.3 mmHg AST 335 U/L
PaO2 73 mmHg ALT 162 U/L
HCO3- 14 mEq/L Lactate 3.1 mmol/L
Creatine kinase 123 U/L
Blood glucose 230 mg/dl BUN 42.3 mg/dl
CBC Cr 3.7 mg/dl
WBC 11890 /mm3 Na+ 164 mEq/L
RBC 7.21×104 /mm3 K+ 6.6 mEq/L
Hct 51.2 % Cl- 96 mEq/L
Hgb 17.4 g/dl Ca2+ 9.8 mg/dl
Plt 7.0×104 /mm3 Phosphorus 3.1 mg/dL
• BP: 105/69 mmHg, HR: 118 bpm, Temperature: 38.9 °C
• O2 saturation: 92% on room air, Respirations: 8 breaths/min and shallow
D. Is there an acid-base disorder present? If so, what is the disturbance? Show your work and explain your answer clearly (HINT: use the step-wise method that I demonstrated during class for determining an acid-base disorder). Is there compensation? Explain? What is the likely cause of the acid-base disturbance, if present? Explain your answer. [6 POINTS]
Describe the nutritional deficiencies that chronic alcoholism has caused in this patient. Why is he displaying ataxic gait, lack of coordination, and confusion? What vitamin or mineral deficiency would these symptoms likely result from? What is this condition called? What other nutritional deficiencies would this patient be at increased risk for? Why? [5 POINTS]
How does chronic alcoholism impact the cardiovascular system? What type of cardiomyopathy is likely to be caused by chronic alcoholism? Explain your answer. [3 POINTS]
Part 8: question 16 [26 POINTS BONUS]
16. **EXTRA CREDIT** Several electrolytes have significant roles and/or effects in the body and have functions in multiple organ systems. One example of an electrolyte that has important roles and/or effects in every organ system within our bodies is Ca2+. Discuss how Ca2+ affects each of the body systems below:
A. Nervous system
B. Muscular system
C. Skeletal system
D. Hematological system
E. Cardiovascular system
F. Immune system
G. Respiratory system
H. Gastrointestinal system
I. Urinary system
J. Reproductive system
K. Integumentary system
L. Endocrine system
M. Lymphatic system
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