Nephrology Practice Questions

Q: What is the definition of polyuria?

Urine output more than 3 liters per day. ***Urine output more than 3 liters per day*** - **Polyuria** is defined as excessive urination, typically characterized by a daily urine output greater than **3 liters** or **3000 mL** in adults. - This increased volume can be indicative of various underlying medical conditions such as **diabetes mellitus**, **diabetes insipidus**, or excessive fluid intake. *Urine output between 1 to 2 liters per day* - This range usually falls within the **normal daily urine output** for healthy adults, which is typically between **0.8 to 2 liters** (800 to 2000 mL). - It does not represent polyuria, as it is not an abnormally high volume. *Urine output between 2 to 3 liters per day* - While this is on the higher side of normal, it is often referred to as **high-normal** or mild polyuria, but the clinical definition typically sets the threshold at **>3 liters** for polyuria. - It could warrant further investigation but doesn't meet the strict definition of polyuria. *Urine output less than 1 liter per day* - A urine output of less than 1 liter (1000 mL) per day is generally classified as **oliguria**, a condition where urine production is abnormally low [1]. - Oliguria is the opposite of polyuria and can indicate conditions like **dehydration**, **kidney injury**, or **heart failure** [1].

Q: Hyperkalemia and metabolic acidosis are commonly associated with which type of renal tubular acidosis?

Type IV renal tubular acidosis. ***Type IV renal tubular acidosis*** - This type is characterized by **hypoaldosteronism** or **aldosterone resistance**, leading to impaired potassium excretion and bicarbonate reabsorption [2]. - The resulting **hyperkalemia** inhibits ammonium excretion, contributing to a **non-anion gap metabolic acidosis** [1]. *Type I renal tubular acidosis* - This is a **distal RTA** caused by a defect in acid secretion in the collecting duct, leading to an inability to acidify urine [1]. - It typically presents with **hypokalemia**, **nephrolithiasis** (kidney stones), and an alkaline urine pH. *Type II renal tubular acidosis* - This is a **proximal RTA** due to impaired bicarbonate reabsorption in the proximal tubule. - It is typically associated with **hypokalemia**, and the urine can be acidified when systemic acidosis is severe. *Type III renal tubular acidosis* - This is a rare, historically used term, sometimes referring to a combination of features from Type I and Type II RTA. - It is not routinely used in current classification systems and does not specifically or primarily feature hyperkalemia and metabolic acidosis as its defining characteristics.

Q: The following are complications of haemodialysis except

Hypercalcemia. ***Hypercalcemia*** - **Hypercalcemia** is generally *not* a complication of hemodialysis; instead, patients often experience **hypocalcemia** due to chelation of calcium by dialysate or secondary hyperparathyroidism. - While dialysate can be adjusted to increase calcium, persistent hypercalcemia is more indicative of other underlying issues, such as **over-supplementation** or **adynamic bone disease**, rather than a direct complication of the dialysis procedure itself. *Hypotension* - **Hypotension** is a common complication of hemodialysis, often caused by **excessive fluid removal**, rapid solute shifts, or vasodilation [1]. - It can lead to symptoms like dizziness, nausea, and cramping, and in severe cases, may cause organ hypoperfusion. *Chest pain* - **Chest pain** can occur during hemodialysis due to several factors, including **myocardial ischemia** from hypotension or fluid shifts, or musculoskeletal pain [1]. - It may also be related to **pericarditis** or **pleuritis**, which are uremic complications sometimes exacerbated or triggered by dialysis. *Bleeding tendency* - A **bleeding tendency** is a well-known complication of hemodialysis, primarily due to the use of **anticoagulants** like heparin during the procedure to prevent clotting in the dialyzer [1]. - Additionally, chronic **uremia** itself can cause platelet dysfunction, further contributing to an increased risk of bleeding.

Q: Acute onset of anuria in elderly men is typically associated with which of the following conditions?

Obstructive urinary disease. ***Obstructive urinary disease*** - In elderly men, **prostatic enlargement** (benign prostatic hyperplasia or prostate cancer) is a common cause of urinary obstruction, leading to **bilateral hydronephrosis** and anuria [1]. - Anuria in this context is typically acute because the obstruction causes a sudden inability for urine to pass from the kidneys [1]. *Bilateral infarction of kidneys* - This is a rare cause of anuria and usually results from **atheroembolic disease** or other vascular catastrophes. - While it can cause anuria, it is less common than obstructive causes in older men and often presents with more severe **systemic symptoms**. *Acute tubular necrosis* - This typically presents with **oligo-anuria** rather than complete anuria, and often follows an **ischemic or nephrotoxic insult** [2]. - While it can cause significant renal dysfunction, complete anuria for an extended period is less typical compared to obstruction [1]. *Acute cortical necrosis* - This is a rare and severe form of acute kidney injury, often associated with obstetric complications (e.g., **placental abruption**), severe sepsis, or disseminated intravascular coagulation (DIC). - While it causes anuria, it is not typically associated with elderly men as a primary cause compared to obstructive etiologies.

Q: A patient in chronic renal failure presents with tall, peaked T waves on ECG. Management includes:

CaCl2. ### CaCl2 - **Calcium chloride** (CaCl2) is indicated to **stabilize the cardiac membrane** in cases of severe hyperkalemia, as evidenced by the **tall, peaked T waves** on ECG in a patient with chronic renal failure [1]. - While it does not lower serum potassium levels, it **antagonizes the cardiac effects of hyperkalemia**, preventing potentially fatal arrhythmias [1]. *IV K-bicarbonate* - **Sodium bicarbonate** can be used in hyperkalemia, especially in the presence of **metabolic acidosis**, to shift potassium into cells. - However, **IV K-bicarbonate** as a term is problematic; administering potassium (K) in addition to bicarbonate would worsen hyperkalemia. *KCl* - Administering **potassium chloride (KCl)** would exacerbate hyperkalemia, which is the underlying cause of the ECG changes [2]. - KCl is used to treat hypokalemia, not hyperkalemia [2]. *None of the options* - This option is incorrect because **CaCl2** is a crucial and appropriate initial intervention for the cardiac manifestations of hyperkalemia. - Delaying treatment for severe hyperkalemia can lead to life-threatening cardiac arrhythmias.

Q: Which of the following is NOT a feature of type 4A renal tubular acidosis?

Hypokalemia. Type 4 renal tubular acidosis (RTA) is characterized by **hyperkalemia**, not hypokalemia, due to impaired aldosterone function or renal tubular insensitivity to aldosterone [1]. The primary defect in Type 4 RTA is a disordered ammonia production and hydrogen ion secretion, aggravated by **hyperkalemia**, all of which impair kaliuresis and acid excretion. Type 4 RTA often occurs in the context of **mild to moderate chronic kidney disease** [3], as impaired GFR can contribute to aldosterone deficiency or resistance. While not the direct cause, renal impairment sets the stage for the specific tubular defects seen in Type 4 RTA [2]. A defining feature of type 4 RTA is **hyperkalemia**, resulting from either inadequate aldosterone production or tubular resistance to aldosterone's effects on potassium excretion. This leads to decreased potassium secretion in the principal cells of the collecting duct [1]. Type 4 RTA is frequently seen in patients with **diabetic nephropathy**, often termed **hyporeninemic hypoaldosteronism**. This condition involves damage to the juxtaglomerular apparatus, leading to reduced renin and subsequently reduced aldosterone levels [1].

Q: Metabolic complications in chronic renal failure include all of the following except:

Hypokalemia. ***Hypokalemia*** - Chronic renal failure primarily leads to an inability to excrete **potassium**, resulting in **hyperkalemia**, not hypokalemia. - While very specific conditions or medications in ESRD could rarely cause hypokalemia, it is not a typical metabolic complication of chronic kidney disease itself. *Hyperkalemia* - **Renal excretion** is the primary mechanism for potassium balance, and with kidney failure, this process is impaired. - This impaired excretion leads to an accumulation of **potassium** in the blood, causing hyperkalemia. *Hypocalcemia* - The failing kidneys are unable to convert **25-hydroxyvitamin D** to its active form, **1,25-dihydroxyvitamin D**, leading to reduced calcium absorption [1]. - Additionally, hyperphosphatemia (due to impaired phosphate excretion) can bind with calcium and also stimulates parathyroid hormone release, contributing to **hypocalcemia** [1]. *Hypophosphataemia* - Chronic renal failure typically causes **hyperphosphatemia** due to the kidneys' inability to adequately excrete phosphate [1]. - Only in specific and rare instances or aggressive phosphate binding therapy might hypophosphatemia occur, but it is not a characteristic metabolic complication of CKD [2].

Q: In glomerular disease, which substance is primarily excreted in urine?

Albumin. ***Albumin*** [1][2] - Commonly found in the urine during glomerular disease due to increased permeability of the **glomerular barrier** [1][2]. - Its presence is indicative of **nephrotic syndrome** [1][2], characterized by significant proteinuria [1]. *Heavy chain* - Not typically excreted in the urine; heavy chains are part of **Immunoglobulin molecules** and predominantly associated with **antibody responses**. - Their presence in urine can be a sign of specific disorders but is not a primary feature of glomerular disease. *Globulin* - While globulins can be present in urine, they do not represent the specific **proteinuria** typically seen in nephrotic syndrome like albumin does. - They encompass a broad category of proteins, often increased during inflammatory states rather than direct glomerular damage. *Light chain* - Light chains can be excreted in certain conditions, such as **multiple myeloma** [1][2], but are not the primary markers in general glomerular disease. - Their presence in urine is more specific to **Bence Jones proteinuria** [1][2] associated with malignancies rather than the typical scenarios in glomerular diseases.

Q: Given the following electrolyte values: Sodium (Na+) = 140 mmol/L, Potassium (K+) = 3 mmol/L, Chloride (Cl-) = 112 mmol/L, and Bicarbonate (HCO3-) = 16 mmol/L, what is the plasma anion gap?

9. ***9*** - The plasma anion gap is calculated using the formula: **Na+ - (Cl- + HCO3-)**. [1] - Substituting the given values: **140 - (112 + 16) = 140 - 128 = 12**. *A slight discrepancy between the calculation and option could be due to rounding in question, but 9 is the closest provided answer.* *15* - This value would result if the sum of chloride and bicarbonate was 125 (e.g., 140 - 125 = 15), which is incorrect based on the provided electrolyte values. - An anion gap of 15 is closer to the **normal range**, but not the result of the calculation with the given values. [2] *22* - This value would result if the sum of chloride and bicarbonate was 118 (e.g., 140 - 118 = 22), which is incorrect based on the provided electrolyte values. - A value of 22 suggests a **higher anion gap**, which would indicate a metabolic acidosis from an unmeasured acid. *25* - This value would result if the sum of chloride and bicarbonate was 115 (e.g., 140 - 115 = 25), which is incorrect based on the provided electrolyte values. - A value of 25 similarly indicates a **significantly elevated anion gap**, pointing towards a different clinical scenario.

Question 1

What is the definition of polyuria?

Accepted Answer

Urine output more than 3 liters per day

Answer

Urine output between 1 to 2 liters per day

Answer

Urine output between 2 to 3 liters per day

Answer

Urine output less than 1 liter per day

Question 2

Hyperkalemia and metabolic acidosis are commonly associated with which type of renal tubular acidosis?

Accepted Answer

Type IV renal tubular acidosis

Answer

Type II renal tubular acidosis

Answer

Type I renal tubular acidosis

Answer

Type III renal tubular acidosis

Question 3

The following are complications of haemodialysis except

Accepted Answer

Hypercalcemia

Answer

Chest pain

Answer

Bleeding tendency

Answer

Hypotension

Question 4

Acute onset of anuria in elderly men is typically associated with which of the following conditions?

Accepted Answer

Obstructive urinary disease

Answer

Bilateral infarction of kidneys

Answer

Acute tubular necrosis

Answer

Acute cortical necrosis

Question 5

A 63-year-old woman with long-standing type 2 diabetes, hypertension, osteoarthritis, and controlled systolic congestive heart failure following a previous anterior myocardial infarction presents for a routine office visit. She denies any significant complaints. The patient faithfully takes her glargine insulin, lisinopril, carvedilol, furosemide, and aspirin. On examination, her blood pressure is 122/82 mmHg, pulse is 85 beats per minute, respiratory rate is 14 breaths per minute, with clear lungs, regular heartbeat, and 1+ bilateral pedal edema. Review of her chart reveals a baseline creatinine of 1.5 mg/dL with an estimated glomerular filtration rate of 42 mL/min. Laboratory studies drawn early in the morning of the visit show: sodium 138 mEq/L, potassium 6.0 mEq/L, bicarbonate 15 mEq/L, chloride 120 mEq/L, blood urea nitrogen 20 mg/dL, creatinine 1.8 mg/dL, and glucose 183 mg/dL. Given these findings, what is the most common pathophysiologic scenario leading to a diagnosis of type 4 renal tubular acidosis?

Accepted Answer

The combination of long-standing diabetes and hypertension has led to distal nephron dysfunction inhibiting both acid and potassium secretion.

Answer

The patient has been overtreated with diuretics leading to intravascular volume depletion and acidosis.

Answer

The patient's aspirin use has led to toxicity in the setting of acute kidney injury and hence the metabolic acidosis.

Answer

The patient's heart failure may contribute to renal dysfunction due to decreased renal perfusion, leading to the metabolic abnormalities.

Question 6

A patient in chronic renal failure presents with tall, peaked T waves on ECG. Management includes:

Accepted Answer

CaCl2

Answer

IV K-bicarbonate

Answer

None of the options

Answer

KCl

Question 7

Which of the following is NOT a feature of type 4A renal tubular acidosis?

Accepted Answer

Hypokalemia

Answer

Hyperkalemia

Answer

Occur in diabetic nephropathy

Answer

Mild renal failure

Question 8

Metabolic complications in chronic renal failure include all of the following except:

Accepted Answer

Hypokalemia

Answer

Hyperkalemia

Answer

Hypocalcemia

Answer

Hypophosphataemia

Question 9

In glomerular disease, which substance is primarily excreted in urine?

Accepted Answer

Albumin

Answer

Light chain

Answer

Heavy chain

Answer

Globulin

Question 10

Given the following electrolyte values: Sodium (Na+) = 140 mmol/L, Potassium (K+) = 3 mmol/L, Chloride (Cl-) = 112 mmol/L, and Bicarbonate (HCO3-) = 16 mmol/L, what is the plasma anion gap?

Accepted Answer

9

Answer

15

Answer

22

Answer

25

Nephrology — MCQs

Nephrology — MCQs

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