CCRN Practice Questions – Endocrine with Complete Solutions

CCRN Practice Questions – Endocrine with Complete Solutions Which laboratory values would differentiate diabetic ketoacidosis (DKA) from a hyperosmolar hyperglycemic state (HHS)? a. Serum glucose of 600 mg/dL b. Serum potassium of 4 mEq/L c. Positive serum ketones d. Serum osmolality of 320 mOsm/L - Answer- Correct answer: c Rationale: In DKA there is an absolute insulin deficiency that causes glycogenolysis and gluconeogenesis. The gluconeogenesis causes the incomplete breakdown of free fatty acids, which results in ketones in the blood and urine. In HHS, there is a relative insulin deficiency that causes glycogenolysis but does not cause gluconeogenesis. Therefore tests for ketones are positive in DKA but typically negative in HHS. Test-Taking Strategy: A serum glucose of 600 mg/dL is abnormal but could be due to DKA or HHS. A serum potassium of 4 mEq/L could be seen in DKA or HHS. Elevated serum osmolality of 320 mOsm/L could be seen in DKA or HHS and is due to dehydration. Only the serum ketones distinguish between the two hyperglycemic crises. A patient with type 1 diabetes mellitus is discharged after myocardial infarction. When teaching the patient about his medications, it is important to inform him that which of the following medications would prevent the early symptoms of hypoglycemia? a. Verapamil (Calan) b. Diazepam (Valium) c. Metoprolol (Lopressor) d. Humulin insulin - Answer- Correct answer: c Rationale: The early symptoms of hypoglycemia are mediated by the sympathetic nervous system. Sympathetic blocking agents would block these symptoms. Metoprolol (Lopressor) is a beta-blocker, which would block the tachycardia, nervousness, and diaphoresis indicative of early hypoglycemia. Test-Taking Strategy: Think "prevent equals block." Option a is a calcium channel blocker, and option c is a beta-blocker. Remember that beta in beta-blocker refers to the receptors of the sympathetic nervous system and that the early indications of hypoglycemia are sympathetic nervous system symptoms. Choose option c A patient received Humulin NPH insulin at 7 AM. He was nauseated and vomiting at lunchtime and did not eat. It is now 3 PM. What are the early signs of hypoglycemia for which the nurse should monitor? a. Decreased skin turgor; abdominal pain; fever b. Tachycardia; tachypnea; diaphoresis c. Thirst; hypotension; fruity odor to breath d. Flushed skin; confusion; rapid, deep breathing - Answer- Correct answer: b Rationale: The early signs of hypoglycemia are mediated by the sympathetic nervous system, which acts to mobilize glucose stores. Later signs of hypoglycemia are related to low glucose levels in the brain (neuroglycopenia). Test-Taking Strategy: Remember that sympathetic nervous system innervation occurs in any physiologic stressor. Because the question says "early," choose the option that identifies sympathetic nervous system signs. Choose option b. A patient received Humulin NPH insulin at 7 AM. He was nauseated and vomiting at lunchtime and did not eat. If this patient develops manifestations of hypoglycemia, treatment would include: a. 25 mL of 50% dextrose in water (D50W). b. glucagon intramuscularly. c. 4 oz of apple juice. d. 100 mL of 5% dextrose in water (D5W). - Answer- Correct answer: a Rationale: The treatment for mild hypoglycemia is 10 to 15 g of carbohydrates. This normally is administered as 4 oz of orange juice if the patient can drink (unless the patient has renal failure when lower potassium, lower water options are better). This patient has not been able to take anything by mouth all day. Glucagon is a hormone that mobilizes glucose from glucose stores but takes longer than directly giving glucose. D5W has 5 g of dextrose per 100 mL, which would provide only 20 calories. D50W has 50 g of dextrose per 100 mL. A volume of 25 mL of D50W would provide 12.5 g of carbohydrate and 50 calories. Test-Taking Strategy: The case presentation is a hypoglycemic patient who is unable to take food by mouth, so eliminate option c. Glucagon should be used only if intravenous administration of glucose is not possible, so eliminate option b. Administration of 100 mL of D5W would provide less than the recommended carbohydrate dosage for mild hypoglycemia. Choose option a. A 25-year-old woman is admitted with diabetic ketoacidosis (DKA). The following laboratory values were reported from blood taken at admission: Serum glucose 450 mg/dL Potassium 4.5 mEq/L pH 7.15 She has received regular insulin bolus, and an infusion has been initiated. Two liters of normal saline has been administered. The last serum glucose is 215 mg/dL, and the pH is 7.32. Which therapy would be inappropriate? a. Changing the intravenous solution to include dextrose b. Adding potassium to the intravenous solution c. Administering sodium bicarbonate d. Slowing the insulin infusion - Answer- Correct answer: c Rationale: Treatment of metabolic acidosis is first of all treatment of the cause. The acidosis in DKA is caused by an insulin deficiency and should be treated with insulin therapy and rehydration. Sodium bicarbonate generally is reserved for pH of 7 or less. Dextrose should be added to the intravenous solution when the serum glucose is less than 250 mg/dL. The serum potassium is normal on admission only because the patient is acidotic and potassium is shifted out of the cell and into the serum. As soon as the pH is corrected, the potassium will shift back into the cell and the serum potassium will drop and need to be replaced. As the serum glucose comes down, the insulin infusion should be adjusted. Test-Taking Strategy: The pH is very close to normal, and sodium bicarbonate is reserved for severely acidotic states A patient had a craniotomy 2 days ago for removal of a tumor. He is awake and talking to the nurse and demonstrates no neurologic deficit. Blood pressure is 110/80 mm Hg, pulse is 92 beats/min, and respiratory rate is 22 breaths/min. Urine outputs have been approximately 60 mL/hr over the last 2 days, but he has had a recent change. He has had 300 to 400 mL/hr of urine output over the last several hours. The urine has a specific gravity of 1.002. The nurse checks his serum glucose and finds that it is 100 mg/dL. The nurse should suspect: a. diabetic ketoacidosis. b. syndrome of inappropriate antidiuretic hormone (SIADH). c. acute adrenal crisis. d. diabetes insipidus. - Answer- Correct answer: d Rationale: The classic sign of diabetes insipidus is diuresis of very dilute urine. The normal serum glucose indicates that this diuresis is not being caused by hyperglycemia. Test-Taking Strategy: Eliminate option a because the serum glucose is normal. Eliminate option b because SIADH causes decreased amounts of urine with high urine specific gravity. Aldosterone is the problem in acute adrenal crisis (option c), and the diuresis that occurs is isotonic. This urine is extremely hypotonic. Remember that the specific gravity of water is 1.000. This urine is much like water because of the inability of the kidney to concentrate it as a result of a deficiency of antidiuretic hormone. Choose option d A patient had a craniotomy 2 days ago for removal of a tumor. He is awake and talking to the nurse and demonstrates no neurologic deficit. Blood pressure is 110/80 mm Hg, pulse is 92 beats/min, and respiratory rate is 22 breaths/min. Urine outputs have been approximately 60 mL/hr over the last 2 days, but he has had a recent change. He has had 300 to 400 mL/hr of urine output over the last several hours. The urine has a specific gravity of 1.002. The nurse checks his serum glucose and finds that it is 100 mg/dL. The nurse would expect the following osmolality of the urine and serum: a. Both are elevated. b. Both are decreased. c. Urine osmolality is decreased, and serum osmolality is increased. d. Urine osmolality is increased, and serum osmolality is decreased. - Answer- Correct answer: c Rationale: The dilute urine has a low osmolality, and as the patient becomes increasingly dehydrated, the serum osmolality will be increased. Test-Taking Strategy: Remember that osmolality is a reflection of solutes in solution. This patient is losing more water than sodium, so the urine osmolality will be low, but the sodium left in the blood will make the serum osmolality high. A patient had a craniotomy 2 days ago for removal of a tumor. He is awake and talking to the nurse and demonstrates no neurologic deficit. Blood pressure is 110/80 mm Hg, pulse is 92 beats/min, and respiratory rate is 22 breaths/min. Urine outputs have been approximately 60 mL/hr over the last 2 days, but he has had a recent change. He has had 300 to 400 mL/hr of urine output over the last several hours. The urine has a specific gravity of 1.002. The nurse checks his serum glucose and finds that it is 100 mg/dL. The intravenous solution most appropriate for fluid replacement would be: a. 5% dextrose in water (D5W). b. normal saline. c. lactated Ringer's solution. d. 10% dextrose in water (D10W). - Answer- Correct answer: a