USMLE Step 3 Quiz
Practice Dialysis And Transplant Care in USMLE Step 3 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.
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A 58-year-old man who is 6 months post-deceased donor renal transplant presents for follow-up. His medications include tacrolimus, mycophenolate mofetil, and prednisone. His blood pressure today is 155/95 mm Hg; it was 150/92 mm Hg one month ago. He has no other medical history. His serum creatinine is stable at 1.4 mg/dL and potassium is 4.2 mEq/L. Which of the following is the most appropriate initial agent for managing his hypertension?
This quiz focuses on Dialysis And Transplant Care, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 3.
Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.
A 58-year-old man who is 6 months post-deceased donor renal transplant presents for follow-up. His medications include tacrolimus, mycophenolate mofetil, and prednisone. His blood pressure today is 155/95 mm Hg; it was 150/92 mm Hg one month ago. He has no other medical history. His serum creatinine is stable at 1.4 mg/dL and potassium is 4.2 mEq/L. Which of the following is the most appropriate initial agent for managing his hypertension?
Explanation: Post-transplant hypertension is common, often exacerbated by immunosuppressive medications, particularly calcineurin inhibitors like tacrolimus. Tacrolimus can cause afferent arteriolar vasoconstriction, leading to hypertension and a decrease in GFR. Dihydropyridine calcium channel blockers, such as amlodipine, are the preferred first-line agents as they cause vasodilation of the afferent arteriole, directly counteracting this effect and potentially improving allograft blood flow. ACE inhibitors or ARBs may cause an acute rise in creatinine and hyperkalemia in this setting. Thiazide diuretics are less effective with a reduced GFR and can worsen electrolyte abnormalities associated with tacrolimus. Beta-blockers are not considered first-line agents for this condition.
A 45-year-old woman on continuous ambulatory peritoneal dialysis (CAPD) for end-stage renal disease presents to the emergency department with a 2-day history of diffuse abdominal pain, fever, and nausea. Her peritoneal dialysis effluent is cloudy. A sample of the effluent is sent for cell count, Gram stain, and culture. The cell count shows 450 WBC/μL with 85% neutrophils. What is the most appropriate next step in management?
Explanation: This patient's presentation is classic for peritonitis, a common and serious complication of peritoneal dialysis. The diagnosis is confirmed by cloudy effluent and a fluid WBC count >100/μL with >50% neutrophils. The standard of care is to initiate empiric intraperitoneal (IP) antibiotics immediately after diagnosis. IP administration achieves high local concentrations and is more effective than intravenous (IV) administration for uncomplicated PD peritonitis. Catheter removal is reserved for severe, refractory, or fungal peritonitis. An abdominal CT scan is not necessary for the initial diagnosis if the clinical picture is clear.
A 38-year-old man who is 9 months post-kidney transplant presents with a progressive rise in his serum creatinine from a baseline of 1.5 mg/dL to 2.4 mg/dL over the past 6 weeks. He has no other symptoms. His immunosuppressive regimen is tacrolimus, mycophenolate, and prednisone. A quantitative urine PCR is positive for BK polyomavirus with a viral load of 100,000 copies/mL. A renal biopsy is pending. What is the most appropriate initial management step?
Explanation: This patient has BK virus-associated nephropathy (BKVAN), a significant cause of allograft dysfunction. The cornerstone of management is a reduction in overall immunosuppression to allow the host immune system to clear the virus. This is typically achieved by first reducing or discontinuing the antimetabolite agent (mycophenolate mofetil or azathioprine). Increasing immunosuppression would worsen the viral replication. Antiviral agents like cidofovir have significant toxicity and are reserved for severe cases unresponsive to immunosuppression reduction. Switching to sirolimus has been studied but is not the standard initial step.
A 55-year-old woman with end-stage renal disease due to polycystic kidney disease had a radiocephalic arteriovenous fistula (AVF) created in her left forearm 10 weeks ago. She is scheduled to begin hemodialysis next week. On examination of the fistula, there is a weak, high-pitched bruit and no palpable thrill. The fistula is small and difficult to palpate. What is the most appropriate next step in her management?
Explanation: This patient's AVF shows signs of non-maturation. A mature fistula should be easily palpable, have a continuous, low-pitched bruit, and a palpable thrill. By 8-12 weeks, the fistula should be ready for use. The physical findings suggest an outflow stenosis or other anatomical problem. The most appropriate next step is to obtain imaging, such as a duplex ultrasound or a fistulogram, to identify the underlying issue, which may be amenable to percutaneous intervention. Proceeding with cannulation is unsafe and likely to fail. Placing a catheter is premature before investigating the cause of fistula failure. Waiting longer is unlikely to result in maturation without intervention.
A 48-year-old woman is evaluated 4 months after a kidney transplant. Her immunosuppressive regimen includes tacrolimus, mycophenolate mofetil, and a tapering dose of prednisone. She reports increased thirst and urination. Laboratory studies show a fasting blood glucose of 152 mg/dL and a hemoglobin A1c of 7.4%. She had no history of diabetes prior to her transplant. This patient's condition is most likely a side effect of which two of her medications?
Explanation: New-onset diabetes after transplantation (NODAT) is a common metabolic complication. The risk is significantly increased by certain immunosuppressive agents. Both glucocorticoids (prednisone) and calcineurin inhibitors (especially tacrolimus) are known to be diabetogenic. Prednisone induces insulin resistance, while tacrolimus is directly toxic to pancreatic beta cells. Mycophenolate mofetil is not significantly associated with the development of NODAT. Therefore, the combination of tacrolimus and prednisone is the most likely cause of this patient's hyperglycemia.
A 72-year-old man with newly diagnosed end-stage renal disease requires initiation of dialysis. He has a history of multiple complex abdominal surgeries for Crohn's disease, resulting in adhesions. He also has severe diabetic retinopathy causing near-blindness and lives with his daughter who works full-time. He expresses a strong desire for a therapy that minimizes disruption to his daily life. Which dialysis modality is most appropriate for this patient?
Explanation: This patient has multiple contraindications to home-based dialysis modalities. His extensive abdominal surgical history makes peritoneal dialysis (both CAPD and APD) high-risk due to potential adhesions affecting catheter function and fluid distribution. His near-blindness and lack of a full-time caregiver make both home hemodialysis and peritoneal dialysis unsafe and impractical, as these require significant patient or caregiver ability for sterile technique and machine operation. Therefore, in-center hemodialysis, where treatment is administered by trained medical staff, is the safest and most appropriate option.
A 52-year-old man who is 7 months post-renal transplant presents with a 2-week history of low-grade fever, malaise, non-productive cough, and progressive dyspnea. His medications include tacrolimus, mycophenolate, and prednisone. He has been compliant with his trimethoprim-sulfamethoxazole prophylaxis. A chest X-ray reveals diffuse bilateral interstitial infiltrates. Bronchoalveolar lavage is performed. Which of the following is the most likely causative organism?
Explanation: The timing of infection post-transplant is critical for diagnosis. The period from 1 to 12 months is the highest risk for opportunistic infections, particularly CMV. This patient's subacute presentation with pneumonitis (fever, cough, dyspnea) and diffuse interstitial infiltrates is classic for CMV infection. While PJP can present similarly, it is less likely given that the patient is compliant with prophylaxis. S. pneumoniae typically causes an acute, lobar pneumonia. BK virus primarily causes nephropathy, not pneumonitis.
A 68-year-old woman on maintenance hemodialysis (Monday-Wednesday-Friday) is admitted with cellulitis and requires intravenous vancomycin. Her dry weight is 70 kg. The hospital protocol suggests a loading dose of 20 mg/kg. After the loading dose is given, what is the most appropriate strategy for maintenance dosing?
Explanation: Vancomycin is a large molecule that is significantly cleared by high-flux hemodialysis. Dosing must be adjusted for renal failure and the dialysis schedule. The standard approach is to give a loading dose, followed by smaller maintenance doses administered after each dialysis session to replace the drug that was removed. Dosing is then guided by pre-dialysis trough levels. Fixed daily or every-48-hour dosing is inappropriate as it does not account for clearance during dialysis and can lead to either toxic or sub-therapeutic levels. A maintenance dose of 500-750 mg post-dialysis is a common starting point.
A 70-year-old man is two hours into his outpatient hemodialysis session. The nurse reports that he is complaining of dizziness and nausea. His blood pressure has dropped from 150/85 mm Hg to 88/52 mm Hg. The ultrafiltration goal for the session is 3.5 liters. Which of the following is the most appropriate initial intervention?
Explanation: Intradialytic hypotension is a common complication of hemodialysis, primarily caused by rapid fluid removal exceeding the plasma refilling rate. The immediate management involves two key steps: first, reducing or temporarily stopping ultrafiltration to halt further volume loss, and second, rapidly expanding the intravascular volume with an intravenous bolus of isotonic crystalloid (e.g., 100-250 mL of normal saline). Placing the patient in the Trendelenburg position is also helpful. Albumin is a second-line agent for refractory cases. Stopping the session is premature, and midodrine is an oral agent used for prevention, not acute treatment.
A 54-year-old man on in-center hemodialysis is undergoing dietary counseling. His most recent pre-dialysis laboratory results included a potassium of 6.4 mEq/L and a phosphorus of 6.1 mg/dL. He reports struggling with dietary restrictions. The patient should be advised that which of the following meals is most likely contributing to his electrolyte abnormalities?
Explanation: This question requires identifying a meal high in both potassium and phosphorus. French fries (from potatoes) are a major source of potassium. Cheese and processed meat (burger patty) are significant sources of phosphorus. The whole wheat bun also contains more phosphorus than a white bun. The other meal options are lower in both electrolytes: chicken and rice are acceptable protein and carb sources; shrimp salad is low in K and Phos; egg whites and white toast are also safe choices.
A 35-year-old woman is 4 weeks post-deceased donor kidney transplant. She presents to the clinic with a 3-day history of low-grade fever, malaise, and tenderness over the graft site in her right iliac fossa. Her urine output has decreased over the past 24 hours. Laboratory studies show her serum creatinine has risen from a baseline of 1.2 mg/dL to 2.8 mg/dL. Her tacrolimus level is within the therapeutic range. What is the most likely diagnosis?
Explanation: The clinical presentation of fever, allograft tenderness, and an acute rise in serum creatinine within the first few months after transplantation is classic for acute cellular (T-cell mediated) rejection. Delayed graft function occurs immediately post-transplant and is characterized by the need for dialysis in the first week. While a UTI must be ruled out, the graft tenderness makes rejection more likely. Tacrolimus toxicity can cause a rise in creatinine, but it is typically not associated with fever and tenderness, and her drug level is therapeutic.
A renal allograft biopsy is performed on a patient presenting with fever, graft tenderness, and a rising creatinine 3 weeks post-transplant. The pathology report shows a diffuse interstitial infiltrate of lymphocytes and tubulitis. There is no evidence of antibody-mediated injury. These findings confirm Banff grade 1A acute cellular rejection. What is the most appropriate initial treatment for this condition?
Explanation: When you encounter post-transplant complications, always classify the rejection type first—this determines your treatment approach. Acute cellular rejection involves T-cell mediated damage to tubules and interstitium, while antibody-mediated rejection shows evidence of complement activation and donor-specific antibodies. This patient has classic Banff grade 1A acute cellular rejection: lymphocytic interstitial infiltrate with tubulitis occurring within the typical 1-6 week timeframe post-transplant. The absence of antibody-mediated injury confirms this is purely cellular rejection. For mild to moderate acute cellular rejection (Banff grades 1A and 1B), high-dose intravenous pulse methylprednisolone is the standard first-line treatment. This rapidly suppresses the inflammatory response and is effective in 80-90% of cases. Choice A (antithymocyte globulin) is reserved for severe acute cellular rejection (Banff grade 2A/3) or steroid-resistant cases, not as initial therapy for grade 1A rejection. Choice B (increasing baseline tacrolimus) is insufficient for treating established acute rejection—you need aggressive immunosuppression to reverse the process, not just maintenance adjustment. Choice C (plasmapheresis and IVIG) treats antibody-mediated rejection by removing circulating antibodies and complement, but this patient has no evidence of antibody-mediated injury. The correct answer is D—pulse steroids are the appropriate initial treatment for this grade of cellular rejection. Study tip: Remember the rejection treatment hierarchy: mild cellular rejection gets pulse steroids first, severe cellular rejection or steroid resistance gets antithymocyte globulin, and antibody-mediated rejection gets plasmapheresis/IVIG. Always match the treatment intensity to the rejection severity.
A 62-year-old man on maintenance hemodialysis three times weekly has a hemoglobin of 9.8 g/dL despite a stable dose of epoetin alfa for the past 3 months. His blood pressure is well-controlled. Further laboratory studies are ordered to evaluate for iron deficiency. Which of the following sets of results would be most consistent with absolute iron deficiency requiring intravenous iron supplementation in this patient?
Explanation: In patients with end-stage renal disease on hemodialysis, the targets for iron status are different from the general population due to chronic inflammation and ESA therapy. Absolute iron deficiency, which indicates depleted iron stores, is typically defined by a transferrin saturation (TSAT) of ≤20% and a ferritin level of <100 ng/mL (or <200 ng/mL in some guidelines). Functional iron deficiency (ferritin >200 ng/mL, TSAT <20%) indicates adequate stores but insufficient mobilization. The values in choice B (Ferritin 80, TSAT 15%) clearly indicate absolute iron deficiency, which is the strongest indication for IV iron therapy to improve ESA response.
A 60-year-old man with no prior medical care presents to the emergency department with confusion and lethargy. Laboratory studies reveal a BUN of 190 mg/dL and serum creatinine of 16.5 mg/dL. He is diagnosed with end-stage renal disease and scheduled for his first hemodialysis session. Near the end of the 2.5-hour session, he becomes agitated, complains of a severe headache, and then experiences a generalized tonic-clonic seizure. This patient's acute neurologic deterioration is best explained by which of the following mechanisms?
Explanation: This patient is experiencing dialysis disequilibrium syndrome (DDS), a rare but serious complication of initial hemodialysis in patients with severe azotemia. The pathophysiology involves the rapid removal of urea from the blood. Because the blood-brain barrier is relatively impermeable to urea, a significant osmotic gradient develops between the plasma and the brain tissue. This gradient drives water into the brain, causing cerebral edema, which leads to neurological symptoms including headache, confusion, and seizures. To prevent DDS, initial dialysis sessions in severely uremic patients are typically shorter and less efficient.
A 42-year-old woman wants to donate a kidney to her brother. Her medical history is significant for well-controlled hypertension for the past 3 years, managed with amlodipine. Her blood pressure in the office is 125/78 mm Hg. Her BMI is 28. Laboratory evaluation reveals a serum creatinine of 0.8 mg/dL, an estimated GFR of 95 mL/min/1.73m², and a 24-hour urine collection shows protein excretion of 250 mg. Which of the following is the strongest contraindication to her serving as a living donor?
Explanation: Living kidney donors undergo rigorous screening to ensure their own long-term health. While controlled hypertension may be acceptable in some older donors, significant proteinuria is a major contraindication. Proteinuria greater than 200-300 mg/day suggests underlying kidney damage and places the donor at a significantly increased risk of developing progressive chronic kidney disease and end-stage renal disease after nephrectomy. Her age, BMI, and well-controlled blood pressure are less concerning than the established proteinuria.
A patient receives a living-related kidney transplant. Immediately after the vascular anastomoses are completed and the kidney is reperfused, the allograft becomes swollen, cyanotic, and flaccid. Urine output, which was briefly present, ceases completely. This event is most likely caused by which of the following?
Explanation: This is a classic description of hyperacute rejection, which occurs within minutes to hours of transplantation. It is a type II hypersensitivity reaction caused by pre-formed recipient antibodies (IgG) against donor antigens, most commonly ABO blood group antigens or HLA class I antigens. The antigen-antibody binding activates the complement system, leading to endothelial damage, inflammation, and thrombosis, causing irreversible graft destruction. T-cell mediated rejection (acute cellular rejection) occurs days to weeks later. Renal artery thrombosis is in the differential but the diffuse cyanosis and swelling are more characteristic of an immune process. Immune complex deposition is characteristic of chronic rejection.
An 88-year-old woman with end-stage renal disease, advanced dementia, and severe peripheral vascular disease is admitted with uremic encephalopathy. The medical team discusses renal replacement therapy with her son, who is her healthcare proxy. The son is concerned that chronic hemodialysis will be a significant burden and may not improve his mother's quality of life, given her cognitive and functional decline. He asks about other options. What is the most appropriate response?
Explanation: This question tests your understanding of shared decision-making and ethical approaches to life-sustaining treatments in patients with multiple serious comorbidities. When facing complex end-of-life decisions, the goal is to align medical interventions with the patient's values and goals while avoiding both premature abandonment of potentially beneficial care and inappropriate prolongation of suffering. The time-limited trial approach in option D represents best practice in this scenario. It acknowledges the uncertainty about whether dialysis will meaningfully improve this patient's quality of life while respecting the family's concerns about treatment burden. A time-limited trial allows the team to assess her response to dialysis over a defined period (typically weeks to months) and then reevaluate based on functional improvement, symptom relief, and quality of life measures. Option A is inappropriately coercive and fails to engage in meaningful shared decision-making. While uremia can be fatal, presenting death as inevitable without dialysis doesn't address the family's legitimate concerns about treatment burden versus benefit. Option B, while potentially informative, doesn't directly address the family's specific concerns or provide a clear path forward. Statistical data alone rarely resolves difficult individual decisions. Option C incorrectly assumes that dementia automatically disqualifies someone from dialysis. While advanced dementia affects prognosis and quality of life considerations, it doesn't create an absolute contraindication. Remember that time-limited trials are valuable tools when the benefit-burden ratio of an intervention is unclear. They provide a structured way to "try and see" while maintaining the option to discontinue if goals aren't met.
A 59-year-old woman on maintenance hemodialysis for 4 years has the following laboratory results: serum calcium 8.4 mg/dL (normal 8.5-10.5), serum phosphorus 7.2 mg/dL (normal 2.5-4.5), and intact parathyroid hormone (PTH) 1100 pg/mL (normal for ESRD <600). She is on a stable dose of sevelamer. Despite dietary counseling, her phosphorus and PTH levels remain elevated. Which of the following is the most appropriate addition to her regimen?
Explanation: This patient has severe secondary hyperparathyroidism, a component of chronic kidney disease-mineral and bone disorder (CKD-MBD), characterized by hyperphosphatemia and markedly elevated PTH. After optimizing phosphate binders and diet, the next step is to target the parathyroid gland directly. Cinacalcet is a calcimimetic that increases the sensitivity of the calcium-sensing receptors on the parathyroid gland to calcium, thereby decreasing PTH secretion without increasing serum calcium or phosphorus. Active vitamin D analogs (like calcitriol or paricalcitol) could also be used, but they can increase calcium and phosphorus absorption, which is undesirable here. Cholecalciferol is an inactive form of vitamin D. Parathyroidectomy is reserved for refractory cases. IV calcium would worsen hyperphosphatemia.