Nephrology Practice Questions

Q: Normal sized to enlarged kidneys in a patient with chronic failure is indicative of which of the following conditions?

Primary amyloidosis. **Explanation:** In most cases of Chronic Kidney Disease (CKD), kidneys are typically shrunken and scarred (small, echogenic kidneys on ultrasound) [1]. However, certain conditions are classic exceptions where kidneys remain **normal-sized or enlarged** despite advanced renal failure. **1. Why Primary Amyloidosis is correct:** In Primary Amyloidosis (AL), there is an extracellular deposition of insoluble amyloid fibrils within the renal parenchyma (glomeruli, tubules, and interstitium). This progressive accumulation increases the overall mass and volume of the kidney, preventing the typical shrinkage seen in chronic failure. Even as the GFR declines, the kidneys remain large and "waxy." **2. Why the other options are incorrect:** * **Benign Nephrosclerosis:** This is the result of long-standing hypertension, leading to hyaline arteriolosclerosis and ischemic atrophy. It characteristically results in **symmetrically shrunken kidneys** with a finely granular surface. * **Chronic Glomerulonephritis:** This represents the end-stage of various glomerular diseases. It is the most common cause of **small, contracted kidneys** due to extensive fibrosis and loss of nephrons. * **Chronic Interstitial Nephritis:** Chronic inflammation of the tubules and interstitium leads to progressive tubular atrophy and interstitial fibrosis, resulting in **small, irregular kidneys [2].** **3. High-Yield Clinical Pearls for NEET-PG:** To remember the causes of **Large Kidneys in CKD**, use the mnemonic **"SHAPE"**: * **S:** **S**cleroderma (Systemic Sclerosis) * **H:** **H**IV-associated nephropathy (HIVAN) * **A:** **A**myloidosis * **P:** **P**olycystic Kidney Disease (ADPKD) * **E:** **E**ndocrinopathy (**Diabetes Mellitus** – the most common cause) *Note: In Diabetes, kidneys are enlarged in the early stages (hyperfiltration) and typically remain normal-sized even when renal failure develops.*

Q: Which of the following is NOT used in the management of hyperkalemia?

50 ml of 50% dextrose. In the management of hyperkalemia, the goal is to stabilize the cardiac membrane, shift potassium into cells, and eventually remove it from the body. **Explanation of the Correct Answer:** **Option A (50 ml of 50% dextrose)** is the correct answer because it is **not** used alone. While insulin is a mainstay of treatment (shifting potassium into cells via Na+/K+ ATPase stimulation), dextrose is only administered alongside insulin to prevent hypoglycemia. Giving 50% dextrose alone can actually worsen hyperkalemia; the resulting hyperosmolality draws water out of cells, which pulls potassium into the extracellular space via "solvent drag," potentially exacerbating the arrhythmia risk. **Explanation of Incorrect Options:** * **B. Sodium Bicarbonate:** It induces alkalosis, which causes a hydrogen-potassium exchange, shifting K+ into the intracellular compartment [1]. It is particularly useful if metabolic acidosis is present. * **C. Salbutamol:** As a Beta-2 agonist, it stimulates the Na+/K+ ATPase pump, promoting the intracellular shift of potassium [2]. * **D. Calcium Gluconate:** This is the first-line treatment for hyperkalemia with ECG changes. It does not lower serum potassium levels but stabilizes the cardiac myocyte membrane to prevent lethal arrhythmias [1]. **NEET-PG High-Yield Pearls:** * **C-BIG-K Mnemonic:** **C**alcium gluconate (Stabilize), **B**icarbonate/Beta-agonists (Shift), **I**nsulin + **G**lucose (Shift), **K**ayexalate/Diuretics/Dialysis (Remove). * **Fastest Acting:** Calcium gluconate (1-3 minutes) but has the shortest duration [1]. * **Definitive Treatment:** Hemodialysis is the most effective method for potassium removal in patients with renal failure.

Q: Which of the following is a common feature of Gitelman syndrome?

Metabolic alkalosis. **Explanation:** **Gitelman syndrome** is an autosomal recessive salt-wasting tubulopathy caused by a loss-of-function mutation in the **SLC12A3 gene**, which encodes the **thiazide-sensitive sodium-chloride (Na-Cl) cotransporter** in the distal convoluted tubule (DCT). 1. **Why Metabolic Alkalosis is Correct:** The defect in the Na-Cl cotransporter leads to increased delivery of sodium and water to the collecting duct. This stimulates the Renin-Angiotensin-Aldosterone System (RAAS). Aldosterone promotes sodium reabsorption in exchange for potassium and **hydrogen ions (H+)** in the intercalated cells. The excessive loss of H+ ions results in **hypokalemic metabolic alkalosis**, mimicking the chronic use of thiazide diuretics. 2. **Analysis of Incorrect Options:** * **A. Hyperkalemia:** Incorrect. Increased distal delivery of sodium and high aldosterone levels lead to significant potassium wasting, resulting in **hypokalemia**. * **C. Hypermagnesemia:** Incorrect. Gitelman syndrome is uniquely characterized by profound **hypomagnesemia** due to magnesium wasting in the DCT. * **D. High calcium excretion:** Incorrect. Unlike Bartter syndrome (which presents with hypercalciuria), Gitelman syndrome is characterized by **hypocalciuria** (low urinary calcium). This occurs because the reduced intracellular sodium in the DCT cells enhances the activity of the basolateral Na/Ca exchanger, promoting calcium reabsorption. **NEET-PG High-Yield Pearls:** * **Gitelman vs. Bartter:** Gitelman presents later (adolescence/adulthood) and features **hypocalciuria** and **hypomagnesemia**. Bartter presents earlier (infancy) with **hypercalciuria** (mimicking loop diuretics). * **Mnemonic:** **G**itelman = **G**radual (late onset) + **G**ood (low) urinary calcium. * **Clinical Presentation:** Patients often present with muscle cramps, fatigue, and salt craving.

Q: All of the following statements are true about adult polycystic kidney disease, except:

Hypertension is rare. Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common hereditary kidney disease [1]. Understanding its systemic nature is crucial for NEET-PG. **Why Option B is the correct answer (The False Statement):** Contrary to the option, **hypertension is very common** in ADPKD, occurring in approximately 70-80% of patients even before a significant decline in GFR. The underlying mechanism is the activation of the **Renin-Angiotensin-Aldosterone System (RAAS)**. As cysts enlarge, they compress intrarenal vasculature, causing localized ischemia, which triggers renin release. Controlling hypertension is the primary intervention to slow disease progression. **Analysis of other options:** * **Option A:** ADPKD follows an **Autosomal Dominant** inheritance pattern, primarily involving mutations in the *PKD1* (85%, Chromosome 16) or *PKD2* (15%, Chromosome 4) genes [1]. * **Option C:** ADPKD is a systemic ciliopathy. **Polycystic Liver Disease (PLD)** is the most common extrarenal manifestation. Cysts can also occur in the pancreas, spleen, and seminal vesicles. * **Option D:** Urinary tract infections, including **pyelonephritis** and infected cysts, are frequent complications due to stasis and structural abnormalities within the distorted renal parenchyma. **NEET-PG High-Yield Pearls:** 1. **Most common extrarenal manifestation:** Liver cysts (70% of patients). 2. **Most serious extrarenal complication:** Berry Aneurysms (Circle of Willis), which can lead to Subarachnoid Hemorrhage (SAH). 3. **Diagnosis:** Ultrasonography is the first-line screening tool (Ravine’s criteria). 4. **Treatment:** ACE inhibitors/ARBs are the drugs of choice for hypertension; **Tolvaptan** (V2 receptor antagonist) is used to slow cyst growth.

Q: What is the most common organism isolated in emphysematous pyelonephritis?

Escherichia coli. **Explanation:** **Emphysematous Pyelonephritis (EPN)** is a severe, necrotizing infection of the renal parenchyma characterized by the presence of gas within the kidney or perinephric space. It is a urological emergency, predominantly seen in patients with uncontrolled diabetes mellitus (approx. 90% of cases) or urinary tract obstruction. [1] **Why Escherichia coli is correct:** * **E. coli** is the most common organism isolated, accounting for approximately **60-70%** of cases. [1] * **Pathophysiology:** In diabetic patients, high tissue glucose levels provide a substrate for facultative anaerobes like *E. coli*. These bacteria undergo mixed-acid fermentation, producing carbon dioxide ($CO_2$) and hydrogen ($H_2$) gas, which accumulates in the renal tissues. **Why other options are incorrect:** * **Klebsiella pneumoniae:** This is the second most common cause (approx. 10-20%). While it also performs fermentation leading to gas production, its prevalence is significantly lower than *E. coli*. * **Proteus mirabilis:** Though associated with staghorn calculi and urease-producing infections, it is a rare cause of EPN compared to the coliforms. * **Pseudomonas aeruginosa:** This is an uncommon isolate in EPN, usually seen in healthcare-associated infections or post-instrumentation, but it is not the primary causative agent. **High-Yield Clinical Pearls for NEET-PG:** * **Risk Factors:** Diabetes Mellitus (most common) and Female gender. [1] * **Diagnosis:** **NCCT Abdomen** is the gold standard (shows gas in the renal parenchyma). * **Management:** Medical management with IV antibiotics and percutaneous drainage (PCD) is the first line. Emergency nephrectomy is reserved for patients who fail conservative therapy. * **Classification:** Often classified using the **Wan et al.** or **Huang and Tseng** criteria based on CT findings.

Question 1

Normal sized to enlarged kidneys in a patient with chronic failure is indicative of which of the following conditions?

Accepted Answer

Primary amyloidosis

Answer

Benign nephrosclerosis

Answer

Chronic glomerulonephritis

Answer

Chronic interstitial nephritis

Question 2

Which of the following is NOT used in the management of hyperkalemia?

Accepted Answer

50 ml of 50% dextrose

Answer

Sodium bicarbonate

Answer

Salbutamol

Answer

Calcium gluconate

Question 3

In which one of the following conditions is a renal biopsy contraindicated?

Accepted Answer

Uncontrolled hypertension

Answer

Acute renal failure

Answer

Nephrotic syndrome

Answer

Isolated hematuria

Question 4

What is the earliest finding in diabetic nephropathy?

Accepted Answer

Urine albumin > 30 mg/dl

Answer

Shrunken kidney

Answer

Fibrin caps

Answer

Elevated creatinine clearance

Question 5

Which of the following is a common feature of Gitelman syndrome?

Accepted Answer

Metabolic alkalosis

Answer

Hyperkalemia

Answer

Hypermagnesemia

Answer

High calcium excretion

Question 6

All of the following statements are true about adult polycystic kidney disease, except:

Accepted Answer

Hypertension is rare

Answer

Autosomal dominant inheritance

Answer

Can be associated with cysts in liver, lungs and pancreas

Answer

Pyelonephritis is common

Question 7

All of the following are examples of microvascular causes of acute kidney injury, EXCEPT:

Accepted Answer

Renal vein thrombosis

Answer

Antiphospholipid antibody syndrome

Answer

Radiation nephritis

Answer

Thrombotic thrombocytopenic purpura

Question 8

Pre-renal azotemia is associated with which of the following characteristic features?

Accepted Answer

Urinary sodium < 10 mmol/L

Answer

Renal failure index > 1

Answer

Urine osmolality < 500 mOsm/kg

Answer

Urinary creatinine/plasma creatinine ratio < 20

Question 9

What is the most common organism isolated in emphysematous pyelonephritis?

Accepted Answer

Escherichia coli

Answer

Proteus

Answer

Pseudomonas

Answer

Klebsiella

Question 10

A patient presents with the following blood biochemical values: Calcium 6 mg/dL; Uric acid 13 mg/dL; Phosphorus 12 mg/dL; Creatinine 6 mg/dL. Which of the following is a possible diagnosis?

Accepted Answer

Uric acid nephropathy

Answer

Krait bite

Answer

Hypercalcemic nephropathy

Answer

Rickets

Nephrology — MCQs

Nephrology — MCQs

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