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Organ System Disorders

Multisystem Disorders Practice Questions

19 free Multisystem Disorders practice questions for the USMLE Step 1. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.

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Question 1 of 19 Medium

A 56-year-old man presents with hypotension, warm flushed skin, and bounding pulses. He is febrile and confused. Which mechanism best explains his shock state?

  1. A Reduced cardiac output from myocardial depression
  2. B Widespread vasodilation due to nitric oxide release
  3. C Severe intravascular volume loss from hemorrhage
  4. D Mechanical obstruction of venous return

Correct answer: Widespread vasodilation due to nitric oxide release

Septic shock causes massive vasodilation via cytokine-mediated nitric oxide release. This results in warm skin, hypotension, and distributive shock.

Question 2 of 19 Medium

A patient with hypovolemic shock from trauma has cool, clammy skin. Which compensatory mechanism is responsible?

  1. A Decreased sympathetic activity
  2. B Increased parasympathetic tone
  3. C Peripheral vasoconstriction
  4. D Histamine release

Correct answer: Peripheral vasoconstriction

Hypovolemic shock triggers sympathetic activation causing peripheral vasoconstriction. This shunts blood to vital organs and causes cool, clammy skin.

Question 3 of 19 Medium

A 70-year-old woman with urosepsis develops acute respiratory distress syndrome (ARDS). Which finding is most characteristic of ARDS physiology?

  1. A Increased lung compliance
  2. B Decreased diffusion barrier
  3. C Noncardiogenic pulmonary edema
  4. D Reduced alveolar protein content

Correct answer: Noncardiogenic pulmonary edema

ARDS is caused by increased pulmonary capillary permeability leading to noncardiogenic pulmonary edema. This causes decreased compliance and impaired oxygenation.

Question 4 of 19 Medium

A diabetic patient presents with confusion, dehydration, and a glucose level of 900 mg/dL. pH is 7.35. Which diagnosis is most likely?

  1. A Diabetic ketoacidosis
  2. B Hyperosmolar hyperglycemic state
  3. C Lactic acidosis
  4. D Starvation ketosis

Correct answer: Hyperosmolar hyperglycemic state

Hyperosmolar hyperglycemic state presents with extreme hyperglycemia, dehydration, and near-normal pH. Ketosis and acidosis are minimal or absent.

Question 5 of 19 Medium

A patient with septic shock is treated with norepinephrine. Which effect does this medication primarily provide?

  1. A Bradycardia with peripheral vasodilation
  2. B Increased heart rate with minimal vasoconstriction
  3. C Vasoconstriction preserving coronary perfusion
  4. D Selective pulmonary artery vasodilation

Correct answer: Vasoconstriction preserving coronary perfusion

Norepinephrine causes potent α1-mediated vasoconstriction, helping restore systemic vascular resistance. It supports blood pressure in septic shock.

Question 6 of 19 Medium

A 48-year-old man with a history of obesity and hypertension is diagnosed with metabolic syndrome. Which laboratory pattern is most consistent with this condition?

  1. A High HDL, low triglycerides
  2. B Low LDL, normal glucose
  3. C High triglycerides, low HDL
  4. D Low fasting glucose, low triglycerides

Correct answer: High triglycerides, low HDL

Metabolic syndrome is characterized by insulin resistance, high triglycerides, low HDL, hypertension, and central obesity. These factors increase cardiovascular risk.

Question 7 of 19 Medium

A trauma patient has signs of obstructive shock. Which finding supports this diagnosis?

  1. A Warm extremities
  2. B Reduced systemic vascular resistance
  3. C Jugular venous distention
  4. D Metabolic alkalosis

Correct answer: Jugular venous distention

Obstructive shock (e.g., tension pneumothorax, tamponade) results in impaired venous return causing jugular venous distention. SVR increases as compensation.

Question 8 of 19 Medium

A septic patient becomes hypotensive after receiving 4 liters of fluid. Which mechanism is responsible for persistent hypotension?

  1. A β1-receptor downregulation
  2. B Increased renal sodium retention
  3. C Cytokine-mediated vasoplegia
  4. D Increased vagal tone

Correct answer: Cytokine-mediated vasoplegia

Septic shock causes vasoplegia—severe vasodilation that does not respond to fluids alone. Cytokines impair vascular smooth muscle tone.

Question 9 of 19 Medium

A patient with anaphylactic shock develops severe bronchospasm and hypotension. Which mediator is primarily responsible?

  1. A Acetylcholine
  2. B Histamine
  3. C Norepinephrine
  4. D Vasopressin

Correct answer: Histamine

Anaphylaxis involves massive mast cell degranulation with histamine release causing bronchoconstriction and vasodilation. Epinephrine reverses these effects.

Question 10 of 19 Medium

A patient with septic shock develops lactic acidosis. Which mechanism contributes most directly?

  1. A Hyperglycemic osmotic diuresis
  2. B Decreased tissue oxygen delivery
  3. C Overproduction of ketone bodies
  4. D Excessive insulin release

Correct answer: Decreased tissue oxygen delivery

Tissue hypoperfusion in shock leads to anaerobic metabolism and lactate accumulation. Lactic acidosis is a marker of poor perfusion.

Question 11 of 19 Medium

A patient with Addison disease presents with hypotension and hyperkalemia. Which mechanism explains these findings?

  1. A Excess aldosterone secretion
  2. B Low cortisol with elevated ACTH
  3. C Low aldosterone causing sodium loss
  4. D High insulin causing potassium shift

Correct answer: Low aldosterone causing sodium loss

Aldosterone deficiency leads to sodium loss, volume depletion, hypotension, and hyperkalemia. This is characteristic of adrenal insufficiency.

Question 12 of 19 Medium

A patient presents with confusion after fasting for 24 hours. Serum glucose is 45 mg/dL. Which hormone is MOST responsible for initial counter-regulation?

  1. A Insulin
  2. B Glucagon
  3. C Epinephrine
  4. D Cortisol

Correct answer: Glucagon

Glucagon is the first hormone to increase during hypoglycemia, stimulating hepatic glucose release. Epinephrine and cortisol act later.

Question 13 of 19 Medium

A patient with sepsis develops disseminated intravascular coagulation (DIC). Which finding is most characteristic?

  1. A Increased fibrinogen levels
  2. B Thrombocytosis
  3. C Widespread microthrombi and bleeding
  4. D Increased antithrombin III activity

Correct answer: Widespread microthrombi and bleeding

DIC results from systemic coagulation activation causing both thrombi and consumption of clotting factors. This leads to bleeding and organ damage.

Question 14 of 19 Medium

A patient with cardiogenic shock has decreased cardiac output. Which compensatory mechanism increases systemic vascular resistance?

  1. A Increased vagal tone
  2. B Sympathetic activation
  3. C Decrease in renin release
  4. D Decreased vasopressin

Correct answer: Sympathetic activation

Sympathetic activation increases SVR to maintain perfusion pressure. However, perfusion to organs may still be inadequate.

Question 15 of 19 Medium

A homeless man with chronic alcoholism has confusion and ataxia. Labs show low glucose and normal ketones. Which deficiency is most likely?

  1. A Folate
  2. B Thiamine
  3. C Vitamin B12
  4. D Niacin

Correct answer: Thiamine

Thiamine deficiency in alcoholism impairs glucose metabolism, leading to Wernicke encephalopathy. Ketone levels remain normal because fatty acid metabolism is intact.

Question 16 of 19 Medium

A patient in hypovolemic shock receives a large saline infusion. Which parameter is expected to improve first?

  1. A Cardiac output
  2. B Systemic vascular resistance
  3. C Left ventricular contractility
  4. D Serum potassium

Correct answer: Cardiac output

Volume resuscitation increases preload, improving cardiac output rapidly. Contractility and SVR changes occur later.

Question 17 of 19 Medium

A patient with severe burns develops profound edema. Which mechanism explains this fluid shift?

  1. A Reduced hydrostatic pressure
  2. B Increased capillary permeability
  3. C Increased plasma oncotic pressure
  4. D Decreased interstitial oncotic pressure

Correct answer: Increased capillary permeability

Burn injury increases capillary permeability, allowing plasma proteins and fluid to leak into interstitial spaces. This causes significant edema.

Question 18 of 19 Medium

A patient in septic shock is started on broad-spectrum antibiotics. After 12 hours his blood pressure improves, but his urine output remains low. Which organ is likely injured?

  1. A Heart
  2. B Kidneys
  3. C Liver
  4. D Lungs

Correct answer: Kidneys

Acute kidney injury is common in septic shock due to sustained hypoperfusion. Low urine output persists even after BP improves.

Question 19 of 19 Medium

A diabetic patient has metabolic syndrome. Which physical finding is most strongly associated?

  1. A Underweight habitus
  2. B Central obesity
  3. C Peripheral muscle wasting
  4. D Enlarged lymph nodes

Correct answer: Central obesity

Central obesity is a hallmark of metabolic syndrome and strongly correlates with insulin resistance. It increases cardiovascular and metabolic risks.

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