Nephrology (CKD, glomerular diseases)

Nephrology (CKD, glomerular diseases) US Medical PG Question 1: A 45-year-old woman comes to the physician because of a 3-month history of worsening fatigue, loss of appetite, itching of the skin, and progressive leg swelling. Although she has been drinking 2–3 L of water daily, she has been passing only small amounts of urine. She has type 1 diabetes mellitus, chronic kidney disease, hypertension, and diabetic polyneuropathy. Her current medications include insulin, torasemide, lisinopril, and synthetic erythropoietin. Her temperature is 36.7°C (98°F), pulse is 87/min, and blood pressure is 138/89 mm Hg. She appears pale. There is 2+ pitting edema in the lower extremities. Sensation to pinprick and light touch is decreased over the feet and legs bilaterally. Laboratory studies show: Hemoglobin 11.4 g/dL Leukocyte count 6000/mm3 Platelet count 280,000/mm3 Serum Na+ 137 mEq/L K+ 5.3 mEq/L Cl− 100 mEq/L HCO3− 20 mEq/L Urea nitrogen 85 mg/dL Creatinine 8 mg/dL pH 7.25 Which of the following long-term treatments would best improve quality of life and maximize survival in this patient?

• A. Peritoneal dialysis
• B. Living donor kidney transplant (Correct Answer)
• C. Cadaveric kidney transplant
• D. Hemofiltration
• E. Fluid restriction

Nephrology (CKD, glomerular diseases) Explanation: ***Living donor kidney transplant*** - A **living donor kidney transplant** offers the best outcomes for **quality of life and survival** in eligible patients with end-stage renal disease (ESRD), particularly when compared to dialysis, due to better graft survival rates and reduced complications. - The patient's symptoms (fatigue, itching, leg swelling, oliguria, high urea nitrogen, creatinine, hyperkalemia, metabolic acidosis) are consistent with **ESRD**, and while she has several comorbidities, she is not explicitly stated to have contraindications for transplantation. *Peritoneal dialysis* - While an effective treatment for ESRD, **dialysis generally provides lower quality of life** and survival benefits compared to successful kidney transplantation. - She already has significant fluid overload symptoms and **oliguria**, making adequate fluid removal through peritoneal dialysis potentially challenging without strict management and impacting her overall well-being. *Cadaveric kidney transplant* - A **cadaveric kidney transplant** is a viable option and offers better outcomes than dialysis, but it generally has **poorer graft survival** and a longer wait time compared to a living donor transplant due to delayed graft function and cold ischemia time. - Given the option, a **living donor transplant is superior** in terms of long-term outcomes and reduces the time spent on dialysis. *Hemofiltration* - **Hemofiltration is a form of renal replacement therapy**, similar to hemodialysis, often used in acute settings or for critically ill patients with severe fluid overload or electrolyte imbalances. - While it can manage her symptoms, it is not a long-term treatment that **improves quality of life or maximizes survival** better than transplantation for ESRD. *Fluid restriction* - **Fluid restriction** is a supportive measure to manage fluid overload in patients with ESRD; however, it addresses symptoms rather than the underlying progressive renal failure. - While necessary as part of supportive care, it does not offer a definitive long-term solution or improve survival for ESRD, which requires **renal replacement therapy or transplantation**.

Nephrology (CKD, glomerular diseases) US Medical PG Question 2: A 64-year-old African American female comes to the physician's office for a routine check-up. The patient's past medical history is significant for hypertension, diabetes, and osteoarthritis in her right knee. Her medications include metformin, glimepiride, lisinopril, metoprolol, hydrochlorothiazide, and ibuprofen as needed. Her only complaint is an unremitting cough that started about 3 weeks ago and she has noticed some swelling around her mouth. The drug most likely responsible for her recent symptoms causes its primary renal hemodynamic effect on which part of the kidney?

• A. Collecting duct
• B. Distal convoluted tubule
• C. Juxtaglomerular cells
• D. Efferent arteriole (Correct Answer)
• E. Afferent arteriole

Nephrology (CKD, glomerular diseases) Explanation: ***Efferent arteriole*** - The patient's symptoms of an **unremitting cough** and **angioedema** (swelling around her mouth) are classic side effects of **ACE inhibitors**, such as **lisinopril**. - ACE inhibitors primarily exert their renal hemodynamic effects by **dilating the efferent arteriole**, leading to a decrease in intraglomerular pressure and glomerular filtration rate. *Collecting duct* - The collecting duct is the primary site of action for **vasopressin (ADH)** and **aldosterone**, regulating water and sodium reabsorption, respectively. - While other medications like **thiazides** (used by the patient) affect distal tubules and collecting ducts indirectly, their direct impact on the collecting duct is not the cause of angioedema or cough. *Distal convoluted tubule* - The distal convoluted tubule is the main site of action for **thiazide diuretics** (e.g., hydrochlorothiazide), which inhibit the Na-Cl cotransporter. - This tubule segment is not directly involved in the mechanism leading to angioedema or cough caused by ACE inhibitors. *Juxtaglomerular cells* - Juxtaglomerular cells are responsible for producing **renin**, which is the initial step in the **renin-angiotensin-aldosterone system (RAAS)**. - While ACE inhibitors block the conversion of angiotensin I to angiotensin II, they do not directly act on the juxtaglomerular cells themselves to cause their side effects. *Afferent arteriole* - The afferent arteriole is primarily regulated by **sympathetic tone** and local factors, and is the main site of action for medications like **NSAIDs** (e.g., ibuprofen, which the patient takes as needed). - While NSAIDs cause **afferent arteriole constriction** and can impair renal function, they do not cause angioedema or a chronic cough.

Nephrology (CKD, glomerular diseases) US Medical PG Question 3: A 45-year-old man presents with a 3-day history of right-sided flank pain due to a lodged ureteral stone. What changes would be expected to be seen at the level of glomerular filtration?

• A. Increase in glomerular capillary oncotic pressure
• B. Increase in Bowman's space oncotic pressure
• C. Increase in filtration fraction
• D. Increase in Bowman's space hydrostatic pressure (Correct Answer)
• E. No change in filtration fraction

Nephrology (CKD, glomerular diseases) Explanation: ***Increase in Bowman's space hydrostatic pressure*** - A lodged ureteral stone causes **obstruction** of urine flow, leading to a backup of fluid in the renal tubules and eventually into **Bowman's space**. - This increased fluid volume in Bowman's space directly raises its **hydrostatic pressure**, which opposes glomerular filtration, thereby reducing the net filtration pressure. *Increase in glomerular capillary oncotic pressure* - **Glomerular capillary oncotic pressure** primarily reflects the protein concentration within the glomerular capillaries, which would not be directly increased by a ureteral stone. - This parameter typically rises when fluid is filtered out, increasing protein concentration in the remaining blood, but not as the initial insult from obstruction. *Increase in Bowman's space oncotic pressure* - **Bowman's space oncotic pressure** is normally very low because the glomerular filtration barrier prevents significant protein filtration. - An increase in this pressure would imply increased protein leakage into Bowman's space, which is not a direct consequence of a ureteral obstruction. *Increase in filtration fraction* - The **filtration fraction** is the ratio of glomerular filtration rate (GFR) to renal plasma flow. - Ureteral obstruction typically **decreases GFR** due to increased Bowman's space hydrostatic pressure, which would lead to a reduction, not an increase, in the filtration fraction, assuming renal plasma flow remains stable or slightly reduced. *No change in filtration fraction* - Ureteral obstruction significantly impacts the forces driving glomerular filtration, primarily by increasing **Bowman's space hydrostatic pressure**. - This change inevitably leads to a **decrease in GFR**, thus altering the filtration fraction, meaning it would not remain unchanged.

Nephrology (CKD, glomerular diseases) US Medical PG Question 4: Activation of the renin-angiotensin-aldosterone system yields a significant physiological effect on renal blood flow and filtration. Which of the following is most likely to occur in response to increased levels of Angiotensin-II?

• A. Decreased renal plasma flow, decreased filtration fraction
• B. Decreased renal plasma flow, increased glomerular capillary oncotic pressure
• C. Increased renal plasma flow, decreased filtration fraction
• D. Increased renal plasma flow, increased filtration fraction
• E. Decreased renal plasma flow, increased filtration fraction (Correct Answer)

Nephrology (CKD, glomerular diseases) Explanation: ***Decreased renal plasma flow, increased filtration fraction*** - **Angiotensin II** causes **efferent arteriolar constriction**, which reduces blood flow leaving the glomerulus, thereby **decreasing renal plasma flow**. - This efferent constriction also increases **glomerular hydrostatic pressure** and reduces plasma flow distal to the glomerulus, leading to a **higher filtration fraction** (GFR/RPF). *Decreased renal plasma flow, decreased filtration fraction* - While **renal plasma flow decreases**, a **decreased filtration fraction** would imply that either GFR decreases disproportionately more than RPF or GFR does not increase despite the RPF reduction, which is not the typical response to **angiotensin II** due to its predominant effect on the **efferent arteriole**. *Decreased renal plasma flow, increased glomerular capillary oncotic pressure* - **Increased glomerular capillary oncotic pressure** is a consequence of increased filtration fraction, as more fluid is filtered out, leaving behind a more concentrated plasma. This option includes a correct element (decreased RPF) but pairs it with a less direct and defining outcome of acute Angiotensin II action as the primary physiological effect. *Increased renal plasma flow, decreased filtration fraction* - **Angiotensin II** causes **vasoconstriction**, predominantly of the efferent arteriole, which by definition would **decrease renal plasma flow**, not increase it. - A **decreased filtration fraction** would be inconsistent with efferent arteriolar constriction which typically raises GFR relative to RPF. *Increased renal plasma flow, increased filtration fraction* - **Angiotensin II** causes **vasoconstriction**, leading to a **decrease in renal plasma flow**, not an increase. - While **filtration fraction is increased**, the initial premise of increased renal plasma flow is incorrect.

Nephrology (CKD, glomerular diseases) US Medical PG Question 5: A 58-year-old man presents to the Emergency Department after 3 hours of intense suprapubic pain associated with inability to urinate for the past day or two. His medical history is relevant for benign prostatic hyperplasia (BPH) that has been under treatment with prazosin and tadalafil. Upon admission, he is found to have a blood pressure of 180/100 mm Hg, a pulse of 80/min, a respiratory rate of 23/min, and a temperature of 36.5°C (97.7°F). He weighs 84 kg (185.1 lb) and is 175 cm (5 ft 7 in) tall. Physical exam, he has suprapubic tenderness. A bladder scan reveals 700 ml of urine. A Foley catheter is inserted and the urine is drained. Initial laboratory tests and their follow up 8 hours after admission are shown below. Admission 8 hours after admission Serum potassium 4.2 mmol/L Serum potassium 4.0 mmol/L Serum sodium 140 mmol/L Serum sodium 142 mmol/L Serum chloride 102 mmol/L Serum chloride 110 mmol/L Serum creatinine 1.4 mg/dL Serum creatinine 1.6 mg/dL Serum blood urea nitrogen 64 mg/dL Serum blood urea nitrogen 62 mg/dL Urine output 250 mL Urine output 260 mL A senior attending suggests a consultation with Nephrology. Which of the following best justifies this suggestion?

• A. Estimated glomerular filtration rate (eGFR)
• B. Urine output (Correct Answer)
• C. Serum creatinine (SCr)
• D. Serum blood urea nitrogen (BUN)
• E. Serum potassium

Nephrology (CKD, glomerular diseases) Explanation: ***Urine output*** - The patient's **urine output is severely reduced** at 260 mL over 8 hours (approximately **32.5 mL/hour**), which constitutes **oliguria** (defined as <0.5 mL/kg/hr; this patient at 84 kg should produce ≥42 mL/hr). - Despite **relief of the post-renal obstruction** via Foley catheterization, the persistent oliguria indicates **intrinsic kidney injury** rather than simple mechanical obstruction. - The combination of **oliguria persisting after decompression** + **rising serum creatinine** (1.4→1.6 mg/dL) meets **KDIGO criteria for Stage 2 AKI** (urine output <0.5 mL/kg/hr for ≥12 hours). - This requires **urgent nephrology consultation** to assess for acute tubular necrosis (ATN), guide fluid management during potential post-obstructive diuresis, and consider renal replacement therapy if oliguria worsens. *Serum creatinine (SCr)* - The serum creatinine **rose from 1.4 to 1.6 mg/dL** despite bladder decompression, which is concerning and suggests intrinsic renal injury. - However, creatinine is a **lagging indicator** of kidney function - it takes 24-48 hours to reflect acute changes in GFR, whereas **urine output is a real-time indicator** of kidney function. - While the rising creatinine supports the need for nephrology involvement, **urine output is the more immediate and actionable parameter** that prompted the attending's suggestion at this early time point. *Estimated glomerular filtration rate (eGFR)* - eGFR is **calculated from serum creatinine** using equations that assume steady-state conditions, which **do not apply in acute kidney injury**. - In the **acute setting with rapidly changing kidney function**, eGFR calculations are unreliable and can significantly overestimate or underestimate true GFR. - Clinicians rely more on **urine output and serial creatinine measurements** rather than eGFR when managing AKI. *Serum blood urea nitrogen (BUN)* - The BUN decreased slightly from 64 to 62 mg/dL, remaining elevated but showing minimal change after catheterization. - Elevated BUN can reflect **pre-renal azotemia, dehydration, or upper GI bleeding** and is less specific for intrinsic kidney injury than oliguria. - The **BUN:Cr ratio** is approximately 40:1 (64/1.6), suggesting a **pre-renal component**, but this alone doesn't justify urgent nephrology consultation as strongly as the persistent oliguria does. *Serum potassium* - Serum potassium levels remain **normal** (4.2→4.0 mmol/L) and do not indicate a metabolic emergency. - While **hyperkalemia** is a common complication of AKI that would warrant nephrology involvement, this patient's potassium is well-controlled and not the driving concern at this time.

Nephrology (CKD, glomerular diseases) US Medical PG Question 6: A 72-year-old woman with a medical history significant for chronic kidney disease stage 4, hypertension, and type 2 diabetes mellitus, presents to the office for a scheduled visit. During her last visit, the physician started discussing with her the possibility of starting her on dialysis for her chronic kidney disease. The patient has no complaints about her health and enjoys spending time with her family. At presentation, she is afebrile; the blood pressure is 139/89 mm Hg and the heart rate is 80/min. On physical examination, her pulses are bounding, the complexion is pale, she has a grade ⅙ holosystolic murmur, breath sounds remain clear, and 2+ pedal edema to the knee. The measurement of which of the following laboratory values is most appropriate to screen for renal osteodystrophy in this patient?

• A. Erythrocyte sedimentation rate
• B. Serum vitamin B-12 level
• C. Serum C-reactive protein level
• D. Serum thyroid-stimulating hormone level
• E. Serum intact parathyroid hormone level (Correct Answer)

Nephrology (CKD, glomerular diseases) Explanation: ***Serum intact parathyroid hormone level*** - **Renal osteodystrophy**, a common complication of **chronic kidney disease (CKD)** stage 4 and 5, is primarily caused by secondary hyperparathyroidism. - **Intact parathyroid hormone (iPTH)** is critical in diagnosing and monitoring this condition, as elevated levels indicate impaired mineral and bone metabolism due to failing kidneys. *Erythrocyte sedimentation rate* - **Erythrocyte sedimentation rate (ESR)** is a general marker of inflammation and is not specific for renal osteodystrophy. - While CKD can be associated with inflammation, ESR does not directly assess mineral and bone disorders. *Serum vitamin B-12 level* - **Vitamin B-12** deficiency can cause anemia and neurological symptoms, but it is not directly involved in the pathogenesis or diagnosis of renal osteodystrophy. - This test would be more relevant if the patient presented with symptoms of **pernicious anemia** or neuropathy. *Serum C-reactive protein level* - **C-reactive protein (CRP)**, like ESR, is a general **inflammatory marker** and does not provide specific information about bone health or mineral metabolism in CKD. - High CRP levels might indicate infection or systemic inflammation but are not used to screen for renal osteodystrophy. *Serum thyroid-stimulating hormone level* - **Thyroid-stimulating hormone (TSH)** assesses **thyroid function**, which is distinct from renal osteodystrophy. - Thyroid disorders can impact bone health, but TSH is not the primary screening test for bone disease related to CKD.

Nephrology (CKD, glomerular diseases) US Medical PG Question 7: A 55-year-old man presents to his primary care physician with a complaint of fatigue for a couple of months. He was feeling well during his last visit 6 months ago. He has a history of hypertension for the past 8 years, diabetes mellitus for the past 5 years, and chronic kidney disease (CKD) for a year. The vital signs include: blood pressure 138/84 mm Hg, pulse 81/min, temperature 36.8°C (98.2°F), and respiratory rate 9/min. On physical examination, moderate pallor is noted on the palpebral conjunctiva and nail bed. Complete blood count results are as follows: Hemoglobin 8.5 g/dL RBC 4.2 million cells/µL Hematocrit 39% Total leukocyte count 6,500 cells/µL Neutrophils 61% Lymphocytes 34% Monocytes 4% Eosinophils 1% Basophils 0% Platelets 240,000 cells/µL A basic metabolic panel shows: Sodium 133 mEq/L Potassium 5.8 mEq/L Chloride 101 mEq/L Bicarbonate 21 mEq/L Albumin 3.1 mg/dL Urea nitrogen 31 mg/dL Creatinine 2.8 mg/dL Uric acid 6.4 mg/dL Calcium 8.1 mg/dL Glucose 111 mg/dL Which of the following explanations best explains the mechanism for his decreased hemoglobin?

• A. Progressive metabolic acidosis
• B. Side effect of his medication
• C. Failure of adequate erythropoietin production (Correct Answer)
• D. Failure of 1-alpha-hydroxylation of 25-hydroxycholecalciferol
• E. Increased retention of uremic products

Nephrology (CKD, glomerular diseases) Explanation: ***Failure of adequate erythropoietin production*** - The patient's history of **chronic kidney disease (CKD)** is the key factor. As kidney function declines, the peritubular interstitial cells in the renal cortex, which produce **erythropoietin (EPO)**, are damaged, leading to inadequate EPO synthesis. - **Erythropoietin** is essential for stimulating red blood cell production in the bone marrow, so its deficiency directly causes **normocytic, normochromic anemia**, consistent with the patient's low hemoglobin (8.5 g/dL) and pallor. *Progressive metabolic acidosis* - While metabolic acidosis can occur in CKD, it primarily impacts overall metabolic function and can mildly suppress bone marrow, but it is not the **primary mechanism** for severe anemia in CKD. - The patient's bicarbonate of 21 mEq/L indicates mild acidosis, not severe enough to be the dominant cause of his profound anemia. *Side effect of his medication* - Although some medications can cause anemia (e.g., ACE inhibitors or angiotensin receptor blockers can rarely worsen renal anemia), there is no information provided about specific medications that would directly cause this degree of **hemoglobin reduction** as their primary side effect in this context. - His complex medical history and lab findings point more directly to a CKD-related etiology for anemia rather than an unmentioned medication side effect. *Failure of 1-alpha-hydroxylation of 25-hydroxycholecalciferol* - This process is crucial for the production of **calcitriol (active vitamin D)** in the kidneys, and its failure primarily leads to **hypocalcemia** and **renal osteodystrophy**. - While related to CKD, impairment of vitamin D activation does not directly explain **decreased hemoglobin production** or significant anemia. *Increased retention of uremic products* - The accumulation of **uremic toxins** in CKD can indeed suppress bone marrow, shorten red blood cell survival, and impair iron utilization, contributing to anemia. - However, the most significant and direct mechanism for anemia in CKD, especially at this stage, is the **lack of erythropoietin production**, which is a hormonal deficiency rather than a toxic effect.

Nephrology (CKD, glomerular diseases) US Medical PG Question 8: A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

• A. "Does the diarrhea typically precede the constipation, or vice-versa?"
• B. "Is the diarrhea foul-smelling?"
• C. "Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"
• D. "Are the symptoms worse in the morning or at night?"
• E. "Can you tell me more about the symptoms you have been experiencing?" (Correct Answer)

Nephrology (CKD, glomerular diseases) Explanation: ***Can you tell me more about the symptoms you have been experiencing?*** - This **open-ended question** encourages the patient to provide a **comprehensive narrative** of their symptoms, including details about onset, frequency, duration, alleviating/aggravating factors, and associated symptoms, which is crucial for diagnosis. - In a patient presenting with vague, intermittent symptoms like alternating constipation and diarrhea, allowing them to elaborate freely can reveal important clues that might not be captured by more targeted questions. *Does the diarrhea typically precede the constipation, or vice-versa?* - While knowing the sequence of symptoms can be helpful in understanding the **pattern of bowel dysfunction**, it is a very specific question that might overlook other important aspects of the patient's experience. - It prematurely narrows the focus without first obtaining a broad understanding of the patient's overall symptomatic picture. *Is the diarrhea foul-smelling?* - Foul-smelling diarrhea can indicate **malabsorption** or **bacterial overgrowth**, which are important to consider in some gastrointestinal conditions. - However, this is a **specific symptom inquiry** that should follow a more general exploration of the patient's symptoms, as it may not be relevant if other crucial details are missed. *Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life* - Quantifying pain intensity is useful for assessing the **severity of discomfort** and monitoring changes over time. - However, for a patient with intermittent rather than acute, severe pain, understanding the **character, location, and triggers** of the pain is often more diagnostically valuable than just a numerical rating initially. *Are the symptoms worse in the morning or at night?* - Diurnal variation can be relevant in certain conditions, such as inflammatory bowel diseases where nocturnal symptoms might be more concerning, or functional disorders whose symptoms might be stress-related. - This is another **specific question** that should come after gathering a more complete initial picture of the patient's symptoms to ensure no key information is overlooked.

Nephrology (CKD, glomerular diseases) US Medical PG Question 9: A 43-year-old man is referred by his family physician because his urine dipstick reveals 3+ protein and urinalysis reveals 1-2 red cells/high power field, but is otherwise negative. He does not have any current complaints. His family history is irrelevant. He denies smoking and alcohol use. His temperature is 36.7°C (98.06°F), blood pressure is 130/82 mm Hg, and pulse is 78/min. Physical examination is unremarkable. Which of the following is the best next step in the management of this patient’s condition?

• A. Reassurance
• B. Repeat the urine dipstick test
• C. 24-hour urine collection (Correct Answer)
• D. Start captopril
• E. Urine culture

Nephrology (CKD, glomerular diseases) Explanation: ***24-hour urine collection*** - The presence of **3+ proteinuria on dipstick** (approximately ≥300 mg/dL) is significant and requires **quantification** to assess the degree of proteinuria and guide further management. - A **24-hour urine collection** is the traditional gold standard method to quantify total protein excretion and determine if the patient has clinically significant proteinuria (>150 mg/day is abnormal; >3.5 g/day indicates nephrotic-range proteinuria). - Alternatively, a **spot urine protein-to-creatinine ratio (PCR)** or **albumin-to-creatinine ratio (ACR)** can be used, but among the given options, 24-hour collection is the appropriate next step. - The concurrent finding of **microscopic hematuria (1-2 RBCs/hpf)** further supports the need for evaluation of possible **glomerular disease** or other renal pathology. *Repeat the urine dipstick test* - Repeating a dipstick is appropriate for **trace or 1+ proteinuria** to rule out transient causes (exercise, fever, orthostatic proteinuria, concentrated urine). - However, **3+ proteinuria is too significant** to simply repeat the dipstick; it requires quantification to determine the severity and guide further diagnostic workup (e.g., renal biopsy if nephrotic-range). *Urine culture* - While infection can cause proteinuria and hematuria, the urinalysis is described as "otherwise negative," suggesting an absence of **leukocytes, nitrites, or bacteria** typical of a urinary tract infection. - The patient is **asymptomatic** without dysuria, frequency, or fever, making infection unlikely. - A urine culture would be appropriate if there were clinical signs of UTI. *Reassurance* - Giving reassurance would be **inappropriate and potentially harmful** given the finding of **3+ proteinuria**, which is a significant indicator of potential renal pathology. - Proteinuria of this magnitude can indicate **glomerulonephritis, diabetic nephropathy, hypertensive nephrosclerosis**, or other kidney diseases requiring further evaluation. - The presence of concurrent **microscopic hematuria** raises additional concern for glomerular disease. *Start captopril* - Captopril, an **ACE inhibitor**, is used to reduce proteinuria and provide renoprotection in patients with **confirmed chronic kidney disease**, particularly in the setting of **diabetes or hypertension**. - Initiating treatment is **premature** without first quantifying the proteinuria, establishing a diagnosis, and ruling out secondary causes. - The patient's blood pressure (130/82 mm Hg) is at the upper limit of normal but does not mandate immediate antihypertensive therapy before completing the diagnostic evaluation.

Nephrology (CKD, glomerular diseases) US Medical PG Question 10: A 55-year-old Caucasian woman visits her family physician for a checkup and to discuss her laboratory results from a previous visit. The medical history is significant for obesity, hypothyroidism, and chronic venous insufficiency. The medications include thyroxine and a multivitamin. In her previous visit, she complained about being hungry all the time, urinating multiple times a day, and craving water for most of the day. Blood and urine samples were obtained. Today her blood pressure is 120/70 mm Hg, the pulse is 80/min, the respiratory rate is 18/min, and the body temperature is 36.4°C (97.5°F). The physical examination reveals clear lungs with regular heart sounds and no abdominal tenderness. There is mild pitting edema of the bilateral lower extremities. The laboratory results are as follows: Elevated SCr for an eGFR of 60 mL/min/1.73 m² Spot urine albumin-to-creatinine ratio 250 mg/g Urinalysis Specific gravity 1.070 Proteins (++) Glucose (+++) Nitrites (-) Microscopy Red blood cells none White blood cells none Hyaline casts few A bedside renal ultrasound revealed enlarged kidneys bilaterally without hydronephrosis. Which of the following kidney-related test should be ordered next?

• A. Renal computed tomography
• B. No further renal tests are required
• C. Urine protein electrophoresis (Correct Answer)
• D. Renal arteriography
• E. Renal biopsy

Nephrology (CKD, glomerular diseases) Explanation: ***Urine protein electrophoresis*** - The patient's symptoms (polyuria, polydipsia, hunger) along with **significant proteinuria** (++ on urinalysis, **albumin-to-creatinine ratio of 250 mg/g**) and **glucosuria** (+++) suggest possible **diabetes mellitus** and associated **diabetic nephropathy**. - While diabetic nephropathy is likely, other proteinuric kidney diseases, such as **monoclonal gammopathy** (e.g., related to multiple myeloma), can also present with proteinuria and enlarged kidneys. Urine protein electrophoresis helps to **differentiate albuminuria from other proteinurias**, such as light chains, which is crucial for diagnosis and treatment. *Renal computed tomography* - This imaging study would be considered if there was suspicion of **renal masses**, stones, or other structural abnormalities not clearly defined by ultrasound, or if **hydronephrosis** was present, which is not the case here. - Given the primary concern is proteinuria with symptoms suggestive of diabetes, a CT scan is not the most immediate next step for characterizing the type of proteinuria. *No further renal tests are required* - This is incorrect because the patient has significant proteinuria and symptoms suggesting a systemic disease that involves the kidneys, requiring further investigation to **confirm the etiology of the kidney damage** and guide management. - The elevated specific gravity, proteinuria, and glucosuria, along with enlarged kidneys, warrant **further diagnostic workup** beyond an eGFR and ACR. *Renal arteriography* - This invasive procedure is used to visualize the **renal arteries** and assess for conditions like **renal artery stenosis** or vasculitis. - There is no clinical indication (e.g., uncontrolled hypertension despite medication, abdominal bruits, flash pulmonary edema) to suggest renal artery stenosis, and the current presentation points toward a primary glomerular issue. *Renal biopsy* - While a **renal biopsy** might eventually be necessary, it is an **invasive procedure** and usually performed after less invasive tests (like urine protein electrophoresis) have been conducted and if the diagnosis remains unclear or if there's a need for precise histological classification, especially if non-diabetic kidney disease is suspected. - In this case, characterizing the type of proteinuria is important first, as **diabetic nephropathy** can often be diagnosed clinically without a biopsy if typical features are present and other causes are ruled out.

Nephrology (CKD, glomerular diseases) Flashcard 1 of 8

Question: How do levels of serum BUN change with kidney dysfunction? _____

Answer: Increased BUN

Nephrology (CKD, glomerular diseases) Flashcard 2 of 8

Question: What cardiac pathology is a consequence of uremia (renal failure)? _____

Answer: Pericarditis

Nephrology (CKD, glomerular diseases) Flashcard 3 of 8

Question: What is the most common cause of end-stage renal disease in the U.S.? _____

Answer: Diabetic glomerulonephropathy

Nephrology (CKD, glomerular diseases) Flashcard 4 of 8

Question: Chronic renal disease is characterized by _____-calcemia

Answer: hypo

Nephrology (CKD, glomerular diseases) Flashcard 5 of 8

Question: Which chemotherapeutic drug is used in the treatment of lupus nephritis?_____

Answer: Mycophenolate mofetil

Nephrology (CKD, glomerular diseases) Flashcard 6 of 8

Question: Membranoproliferative glomerulonephritis has a(n) _____ response to corticosteroids

Answer: poor

Nephrology (CKD, glomerular diseases) Flashcard 7 of 8

Question: Fabry's disease

Answer:

Extra Information: accumulation of ceramide trihexosideperipheral neuropathy in hands/feet, angiokeratomas, cardiovascular and renal diseaseXRα-galactosidase A

Nephrology (CKD, glomerular diseases) Flashcard 8 of 8

Question: autosomal dominant polycystic kidney disease (ADPKD)

Answer:

Extra Information: in adult: flank pain, hematuria, hypertension, progressive renal failurebilateral massive enlargement of kidneys with cystsADPKD1