Fluid and electrolyte management Practice Questions

Question 1

A physician at an internal medicine ward notices that several of his patients have hyponatremia without any associated symptoms. Severe hyponatremia, often defined as < 120 mEq/L, is associated with altered mental status, coma, and seizures, and warrants treatment with hypertonic saline. Because some patients are chronically hyponatremic, with serum levels < 120 mEq/L, but remain asymptomatic, the physician is considering decreasing the cutoff for severe hyponatremia to < 115 mEq/L. Changing the cutoff to < 115 mEq/L would affect the validity of serum sodium in predicting severe hyponatremia requiring hypertonic saline in which of the following ways?

Accepted Answer

Increased specificity and decreased negative predictive value

Answer

Increased sensitivity and decreased positive predictive value

Answer

Increased specificity and decreased positive predictive value

Answer

Decreased specificity and increased negative predictive value

Answer

Decreased sensitivity and decreased positive predictive value

Question 2

A 7-year-old boy is brought to the emergency room because of severe, acute diarrhea. He is drowsy with a dull, lethargic appearance. He has sunken eyes, poor skin turgor, and dry oral mucous membranes and tongue. He has a rapid, thready pulse with a systolic blood pressure of 60 mm Hg and his respirations are 33/min. His capillary refill time is 6 sec. He has had no urine output for the past 24 hours. Which of the following is the most appropriate next step in treatment?

Accepted Answer

Start IV fluid resuscitation with normal saline or Ringer’s lactate, along with monitoring of vitals and urine output

Answer

Start IV fluid resuscitation by administering colloid solutions

Answer

Provide oral rehydration therapy to correct dehydration

Answer

Give initial IV bolus of 2 L of Ringer’s lactate, followed by packed red cells, fresh frozen plasma, and platelets in a ratio of 1:1:1

Answer

Give antidiarrheal drugs

Question 3

A 46-year-old woman presents to the clinic complaining that she “wets herself.” She states that over the past year she has noticed increased urinary leakage. At first it occurred only during her job, which involves restocking shelves with heavy appliances. Now she reports that she has to wear pads daily because leakage of urine will occur with simply coughing or sneezing. She denies fever, chills, dysuria, hematuria, or flank pain. She has no significant medical or surgical history, and takes no medications. Her last menstrual period was 8 months ago. She has 3 healthy daughters that were born by vaginal delivery. Which of the following tests, if performed, would most likely identify the patient’s diagnosis?

Accepted Answer

Q-tip test

Answer

Methylene blue dye

Answer

Post-void residual volume

Answer

Urodynamic testing

Answer

Estrogen level

Question 4

The serum brain natriuretic peptide and N-terminal pro-BNP are elevated. A diagnosis of heart failure with preserved ejection fraction is made. In addition to supplemental oxygen therapy, which of the following is the most appropriate initial step in management?

Accepted Answer

Intravenous furosemide therapy

Answer

Intravenous dobutamine

Answer

Intravenous morphine therapy

Answer

Thoracentesis

Answer

Intermittent hemodialysis

Question 5

On cardiology service rounds, your team sees a patient admitted with an acute congestive heart failure exacerbation. In congestive heart failure, decreased cardiac function leads to decreased renal perfusion, which eventually leads to excess volume retention. To test your knowledge of physiology, your attending asks you which segment of the nephron is responsible for the majority of water absorption. Which of the following is a correct pairing of the segment of the nephron that reabsorbs the majority of all filtered water with the means by which that segment absorbs water?

Accepted Answer

Proximal convoluted tubule via passive diffusion following ion reabsorption

Answer

Distal convoluted tubule via passive diffusion following ion reabsorption

Answer

Distal convoluted tubule via aquaporin channels

Answer

Thick ascending loop of Henle via passive diffusion following ion reabsorption

Answer

Collecting duct via aquaporin channels

Question 6

A 21-year-old woman is admitted to the hospital for severe malnutrition with a BMI of 15 kg/m2. Past medical history is significant for chronic anorexia nervosa. During the course of her stay, she is treated with parenteral fluids and nutrition management. On the 4th day, her status changes. Her blood pressure is 110/75 mm Hg, heart rate is 120/min, respiratory rate is 25/min, and temperature is 37.0°C (98.6°F). On physical exam, her heart is tachycardic with a regular rhythm and her lungs are clear to auscultation bilaterally. She appears confused, disoriented, and agitated. Strength in her lower extremities is 4/5. What is the next step in management?

Accepted Answer

Measure electrolytes

Answer

MRI of the brain

Answer

Administer insulin

Answer

Arrange for outpatient counseling

Answer

Doppler ultrasound on lower extremities

Question 7

A 45-year-old man presents to the physician with limb weakness over the last 24 hours. He is an otherwise healthy man with no significant past medical history. On physical examination, his vital signs are stable. On neurological examination, there is decreased strength in the muscles of all 4 extremities, and the deep tendon reflexes are depressed. A detailed laboratory evaluation shows that he has generalized decreased neuronal excitability due to an electrolyte imbalance. Which of the following electrolyte imbalances is most likely to be present in the man?

Accepted Answer

Acute hypercalcemia

Answer

Acute hypochloremia

Answer

Acute hypernatremia

Answer

Acute hyperkalemia

Answer

Acute hypomagnesemia

Question 8

A 29-year-old man is brought to the emergency room 6 hours after the onset of severe epigastric pain and vomiting. His heart rate is 110/min and blood pressure is 98/72 mm Hg. He is diagnosed with acute pancreatitis, and fluid resuscitation with normal saline is initiated. Which of the following is the most likely immediate effect of fluid resuscitation in this patient?

Accepted Answer

Increase in myocardial oxygen demand

Answer

Increase in plasma oncotic pressure

Answer

Increase in glomerular filtration fraction

Answer

Increase in volume of distribution

Answer

Increase in cardiac afterload

Question 9

A 78-year-old male with history of coronary artery disease, status post coronary stent placement currently on aspirin and clopidogrel was found down in his bathroom by his wife. His GCS score was 3 and an accurate physical exam is limited. A stat non-contrast CT scan of his brain demonstrated a large right parietal intracranial hemorrhage with surrounding edema. He was promptly transferred to the intensive care unit (ICU) for monitoring. Over the next day, his mental status continues to worsen but repeat CT scan shows no new bleeding. In addition, the patient’s urinary output has been >200 cc/hr over the last several hours and increasing. His temperature is 99.0 deg F (37.2 deg C), blood pressure is 125/72 mmHg, pulse is 87/min, and respirations are 13/min. Which of the following values would most likely correspond to the patient’s urine specific gravity, urine osmolality, plasma osmolality, and serum sodium?

Accepted Answer

Low, Low, High, High

Answer

Low, High, High, High

Answer

High, High, Low, Low

Answer

Low, Low, High, Low

Answer

High, Low, Low, High

Question 10

A 24-year-old woman is brought to the emergency department after being assaulted. The paramedics report that the patient was found conscious and reported being kicked many times in the torso. She is alert and able to respond to questions. She denies any head trauma. She has a past medical history of endometriosis and a tubo-ovarian abscess that was removed surgically two years ago. Her only home medication is oral contraceptive pills. Her temperature is 98.5°F (36.9°C), blood pressure is 82/51 mmHg, pulse is 136/min, respirations are 24/min, and SpO2 is 94%. She has superficial lacerations to the face and severe bruising over her chest and abdomen. Her lungs are clear to auscultation bilaterally and her abdomen is soft, distended, and diffusely tender to palpation. Her skin is cool and clammy. Her FAST exam reveals fluid in the perisplenic space.

Which of the following is the next best step in management?

Accepted Answer

Emergency laparotomy

Answer

Abdominal radiograph

Answer

Abdominal CT

Answer

Fluid resuscitation

Answer

Diagnostic peritoneal lavage

Fluid and electrolyte management

Study Resources

Lessons

Questions

Flashcards

Lessons

Body fluid compartments

Assessment of volume status

Crystalloid vs. colloid solutions

Maintenance fluid requirements

Replacement of ongoing losses

Electrolyte disorders (Na, K, Ca, Mg)

Acid-base disorders in surgical patients

Goal-directed fluid therapy

Fluid management in special populations

Transfusion triggers and strategies

Blood component therapy

Massive transfusion protocols

Point-of-care coagulation testing

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