Nephrology Practice Questions

Q: Which of the following is false regarding Bartter syndrome?

Metabolic acidosis. **Explanation:** **Bartter syndrome** is a group of autosomal recessive disorders characterized by a defect in the thick ascending limb (TAL) of the loop of Henle. It mimics the effect of **Loop diuretics** (like Furosemide) by inhibiting the Na-K-2Cl cotransporter (NKCC2). **Why Metabolic Acidosis is the Correct Answer (False Statement):** Bartter syndrome causes **Metabolic Alkalosis**, not acidosis. The failure of sodium reabsorption in the TAL leads to increased distal delivery of sodium to the collecting duct. To reabsorb this sodium, the body exchanges it for Potassium ($K^+$) and Hydrogen ions ($H^+$) via the action of aldosterone [1]. The excessive loss of $H^+$ ions in the urine results in **hypokalemic metabolic alkalosis** [2]. **Analysis of Other Options:** * **A. Hypokalemia:** Increased distal delivery of sodium leads to excessive potassium secretion in the collecting ducts, causing significant hypokalemia [1]. * **B. Renal stones:** In the TAL, calcium reabsorption is dependent on the lumen-positive potential created by potassium recycling. In Bartter syndrome, this is disrupted, leading to **hypercalciuria**. This increased urinary calcium often leads to nephrocalcinosis or renal stones. * **C. Increased aldosterone:** The loss of salt and water leads to volume depletion, which activates the Renin-Angiotensin-Aldosterone System (RAAS), resulting in **secondary hyperaldosteronism** [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Bartter vs. Gitelman:** Bartter syndrome presents early in life with polyuria, polydipsia, and **hypercalciuria**. Gitelman syndrome (mimicking Thiazides) presents later in life and is characterized by **hypocalciuria** and hypomagnesemia. * **Blood Pressure:** Despite high renin and aldosterone levels, patients with Bartter syndrome are typically **normotensive** or hypotensive due to salt wasting. * **Key Association:** It is associated with juxtaglomerular apparatus hyperplasia.

Q: Which of the following is NOT a feature of the maintenance phase of acute kidney injury?

Hypercalcemia. In the **maintenance phase** of Acute Kidney Injury (AKI), the Glomerular Filtration Rate (GFR) reaches its nadir, leading to the accumulation of metabolic waste and electrolyte imbalances. ### **Why Hypercalcemia is the Correct Answer** **Hypocalcemia**, not hypercalcemia, is the classic feature of the maintenance phase of AKI. This occurs due to two primary mechanisms: 1. **Reduced Vitamin D activation:** The damaged renal parenchyma cannot convert 25-hydroxyvitamin D into its active form (1,21-dihydroxyvitamin D). 2. **Hyperphosphatemia:** Elevated phosphate levels (due to decreased excretion) lead to the precipitation of calcium-phosphate salts in soft tissues, further lowering serum calcium [1]. *Note: Hypercalcemia is only seen during the **recovery (diuretic) phase** if there is mobilization of calcium from tissues or underlying rhabdomyolysis.* ### **Explanation of Incorrect Options** * **Hyperuricemia (A):** Reduced GFR leads to decreased renal clearance of uric acid, causing its accumulation. * **Hypermagnesemia (B):** Magnesium is primarily excreted by the kidneys. In AKI, impaired excretion leads to elevated levels, which can cause neuromuscular depression. * **Hypernatremia (C):** While hyponatremia is more common (due to water retention), hypernatremia can occur if there is a disproportionate loss of free water or excessive administration of sodium-containing fluids [1]. ### **High-Yield Clinical Pearls for NEET-PG** * **Most common electrolyte abnormality in AKI:** Hyperkalemia (due to decreased distal delivery of sodium and reduced K+ secretion). * **Metabolic state:** High anion gap metabolic acidosis (due to retention of organic acids like phosphates and sulfates). * **Recovery Phase:** Watch for **hypokalemia** and **hypomagnesemia** due to osmotic diuresis as the tubular function lags behind GFR recovery.

Q: A 30-year-old man presents with hematuria. Examination reveals an elevated blood pressure of 164/94 mm Hg. An ultrasound of the kidneys shows multiple renal cysts in both kidneys. His father had a similar condition. Which of the following is NOT associated with this syndrome?

Rheumatoid arthritis (RA). The clinical presentation of a young male with hypertension, hematuria, bilateral multiple renal cysts, and a positive family history (father) is diagnostic of **Autosomal Dominant Polycystic Kidney Disease (ADPKD)** [1]. **Why Option D is the Correct Answer:** **Rheumatoid Arthritis (RA)** is an autoimmune inflammatory joint disease and has **no known association** with ADPKD. ADPKD is a systemic genetic disorder involving connective tissue and epithelial cell abnormalities, but it does not predispose patients to RA. **Analysis of Incorrect Options:** * **Option A (Liver cysts):** Polycystic liver disease is the **most common extra-renal manifestation** of ADPKD. While usually asymptomatic, they increase in frequency with age [1]. * **Option B (Intracranial aneurysms):** Approximately 5-10% of ADPKD patients develop "Berry aneurysms" in the Circle of Willis. Rupture leads to subarachnoid hemorrhage, a major cause of mortality. * **Option C (Autosomal dominant inheritance):** ADPKD follows an autosomal dominant pattern, typically caused by mutations in the **PKD1** (Chromosome 16 - 85% cases) or **PKD2** (Chromosome 4 - 15% cases) genes [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of death:** Cardiovascular disease (due to hypertension and LVH). * **Other Extra-renal manifestations:** Pancreatic cysts, Mitral Valve Prolapse (MVP), diverticulosis, and seminal vesicle cysts. * **Diagnosis:** Ultrasound is the primary screening tool. Criteria are based on the number of cysts relative to age (e.g., ≥3 cysts bilaterally in ages 15–39). * **Treatment:** Tolvaptan (V2-receptor antagonist) is used to slow disease progression in rapidly progressing cases.

Q: Which of the following leads to hyponatremia and low osmolality?

CHF. **Explanation:** The correct answer is **CHF (Congestive Heart Failure)**. **1. Why CHF is correct:** Hyponatremia is classified based on serum osmolality. CHF causes **hypoosmolar hypervolemic hyponatremia** [1]. In CHF, decreased effective arterial blood volume (EABV) triggers the baroreceptors, leading to a non-osmotic release of **Antidiuretic Hormone (ADH)**. ADH acts on the V2 receptors in the collecting ducts, causing water retention that exceeds sodium retention [1]. This results in a "dilutional" hyponatremia where both serum sodium and serum osmolality are low. **2. Why the other options are incorrect:** * **Hyperlipidemia (A) and Hyperproteinemia (B):** These cause **Pseudohyponatremia**. In these conditions, the lipid or protein fraction of the plasma is increased, leading to a falsely low sodium measurement when using older flame photometry. Crucially, the **serum osmolality remains normal** (Isotonic hyponatremia). * **IVIG therapy (C):** High-dose IVIG can lead to **Translocational Hyponatremia**. The infusion of sucrose (often used as a stabilizer in IVIG) increases plasma osmolality, drawing water from the intracellular to the extracellular space. This results in hyponatremia with **high serum osmolality** (Hypertonic hyponatremia). **3. High-Yield NEET-PG Pearls:** * **True Hyponatremia** is always associated with **low serum osmolality** (<280 mOsm/kg). * **Hypertonic Hyponatremia:** Think Hyperglycemia or Mannitol [2]. * **Isotonic Hyponatremia (Pseudohyponatremia):** Think Hypertriglyceridemia or Paraproteinemia (Multiple Myeloma). * **Urine Sodium in CHF:** Typically **<20 mEq/L** (due to RAAS activation), helping differentiate it from renal causes of volume overload [1].

Q: All of the following are true about Rhabdomyolysis, except:

Hypercalcemia. Explanation: Rhabdomyolysis involves the rapid breakdown of skeletal muscle, leading to the release of intracellular contents into the systemic circulation. **Why Hypercalcemia is the Correct Answer (The Exception):** In the **acute phase** of rhabdomyolysis, **hypocalcemia** (low calcium) is typically observed rather than hypercalcemia. This occurs because calcium deposits into the damaged muscle tissues (dystrophic calcification) and binds with the excess phosphate released from cells. While hypercalcemia can occur later during the recovery phase (due to the mobilization of these deposits), it is not a characteristic feature of the initial presentation. **Analysis of Other Options:** * **Hyperuricemia (A):** Muscle breakdown releases purines, which are metabolized by the liver into uric acid. This can lead to secondary gout or contribute to acute kidney injury (AKI). * **Hyperphosphatemia (B):** Phosphorus is a major intracellular anion. Massive cell lysis releases large amounts of phosphate into the blood. * **Elevated Creatine Kinase (D):** CK is the most sensitive marker for muscle damage. Levels typically exceed five times the upper limit of normal (often >10,000 U/L) and are diagnostic of the condition. **NEET-PG High-Yield Pearls:** * **Classic Triad:** Muscle pain, weakness, and dark (tea-colored) urine. * **Urinalysis Paradox:** The dipstick is positive for "blood" (due to myoglobinuria), but microscopy shows **no RBCs**. * **Most Common Electrolyte Abnormality:** Hyperkalemia (the most life-threatening complication). * **Treatment:** Aggressive fluid resuscitation (Normal Saline) to maintain urine output and prevent Myoglobin-induced AKI.

Q: A 12-year-old boy presented with severe vomiting and diarrhea. He was brought to the hospital due to severe oliguria. He was given IV fluids and furosemide without any diuresis. Blood biochemistry revealed: Urea 120 mg% and serum creatinine 4 mg%. What is the most likely diagnosis?

Hemolytic uremic syndrome. ### Explanation The correct diagnosis is **Hemolytic Uremic Syndrome (HUS)**. **Why it is correct:** The clinical triad of HUS consists of **Microangiopathic Hemolytic Anemia (MAHA), Thrombocytopenia, and Acute Kidney Injury (AKI)** [1], [2]. In children, the most common form is "D+ HUS" (Diarrhea-associated), typically caused by Shiga toxin-producing *E. coli* (O157:H7) [1]. The patient’s history of severe diarrhea followed by oliguria and significantly elevated nitrogenous waste (Urea 120, Creatinine 4) is a classic presentation [2]. The **failure to respond to IV fluids and furosemide** indicates established intrinsic renal damage (thrombotic microangiopathy), which is characteristic of HUS rather than simple dehydration [1]. **Why incorrect options are wrong:** * **Prerenal Azotemia:** While diarrhea causes dehydration, prerenal AKI should respond to aggressive fluid resuscitation with an increase in urine output. The lack of diuresis here points toward intrinsic damage. * **Acute Tubular Necrosis (ATN):** While ATN can follow severe dehydration, the specific prodrome of diarrhea in a pediatric patient strongly favors HUS. In exams, "diarrhea + renal failure" in a child is HUS until proven otherwise. * **Acute Glomerulonephritis (AGN):** AGN typically presents with hematuria (cola-colored urine), hypertension, and edema, usually following a respiratory or skin infection (e.g., PSGN), not a diarrheal illness. **Clinical Pearls for NEET-PG:** * **Most common cause of AKI in children:** HUS. * **Pathogenesis:** Shiga toxin causes endothelial injury, leading to platelet microthrombi in the glomerular capillaries [1]. * **Peripheral Smear:** Look for **Schistocytes** (fragmented RBCs) [1]. * **Management:** Primarily supportive (dialysis if needed). Antibiotics and anti-motility agents are generally avoided as they may worsen toxin release.

Question 1

A patient presents with hematuria, proteinuria, and hypertension. Which of the following conditions is most likely associated with normal serum complement levels in this clinical scenario?

Accepted Answer

Henoch-Schonlein purpura

Answer

Mixed essential cryoglobulinemia

Answer

Hepatitis C-associated membranoproliferative glomerulonephritis

Answer

Diffuse proliferative lupus nephritis

Question 2

Which of the following is false regarding Bartter syndrome?

Accepted Answer

Metabolic acidosis

Answer

Hypokalemia

Answer

Renal stones

Answer

Increased aldosterone

Question 3

A 30-year-old man presents with generalized edema and hypertension. Urine examination shows sub-nephrotic proteinuria (< 2 gm) and microscopic hematuria. Serum complement levels are decreased and he is positive for anti-hepatitis C antibodies. What is the most likely diagnosis?

Accepted Answer

Membranoproliferative glomerulonephritis (MPGN)

Answer

Post-streptococcal Glomerulonephritis (PSGN)

Answer

Mixed cryoglobulinemia

Answer

Focal segmental Glomerulosclerosis (FSGS)

Question 4

Which of the following is NOT a feature of the maintenance phase of acute kidney injury?

Accepted Answer

Hypercalcemia

Answer

Hyperuricemia

Answer

Hypermagnesemia

Answer

Hypernatremia

Question 5

Which of the following statements is WRONG regarding adult polycystic kidney disease?

Accepted Answer

The presentation is bilateral

Answer

Kidneys are enlarged in size

Answer

Patients tend to have extra-renal congenital anomalies

Answer

Mitral valve prolapse may be present

Question 6

Hemodialysis can be performed for long periods from the same site due to which of the following?

Accepted Answer

Arteriovenous fistula results in aerialization of vein

Answer

Arteriovenous fistula reduces bacterial contamination of site

Answer

Arteriovenous fistula reduces chances of graft failure

Answer

Arteriovenous fistula facilitates small bore needles for high flow rates

Question 7

A 30-year-old man presents with hematuria. Examination reveals an elevated blood pressure of 164/94 mm Hg. An ultrasound of the kidneys shows multiple renal cysts in both kidneys. His father had a similar condition. Which of the following is NOT associated with this syndrome?

Accepted Answer

Rheumatoid arthritis (RA)

Answer

Liver cysts

Answer

Intracranial aneurysms

Answer

Autosomal dominant inheritance

Question 8

Which of the following leads to hyponatremia and low osmolality?

Accepted Answer

CHF

Answer

Hyperlipidemia

Answer

Hyperproteinemia

Answer

IVIG therapy

Question 9

All of the following are true about Rhabdomyolysis, except:

Accepted Answer

Hypercalcemia

Answer

Hyperuricemia

Answer

Hyperphosphatemia

Answer

Elevated Creatine kinase

Question 10

A 12-year-old boy presented with severe vomiting and diarrhea. He was brought to the hospital due to severe oliguria. He was given IV fluids and furosemide without any diuresis. Blood biochemistry revealed: Urea 120 mg% and serum creatinine 4 mg%. What is the most likely diagnosis?

Accepted Answer

Hemolytic uremic syndrome

Answer

Prerenal azotemia

Answer

Acute glomerulonephritis

Answer

Acute tubular necrosis

Nephrology — MCQs

Nephrology — MCQs

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