Nephrology — MCQs
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What are the classic clinical signs suggestive of acute pyelonephritis?
Pre-Renal Azotemia is characterized by all of the following findings, EXCEPT:
What is the mechanism of hypokalemia in Gitelman syndrome?
A 43-year-old woman develops acute renal failure following an emergency resection of a leaking abdominal aortic aneurysm. Three days after surgery, the following laboratory values are obtained: Serum electrolytes (mEq/L): Na+:127; K+:5.9; Cl-:92; HCO3-:15. Blood urea nitrogen: 82 mg/dL. Serum creatinine: 6.7 mg/dL. The patient has gained 4 kg since surgery and is mildly dyspneic at rest. Eight hours after these values are reported, an electrocardiogram shows peaked T waves. What is the initial treatment for this patient?
Which drug can be used in patients of cardio-renal syndrome?
Which of the following conditions is NOT associated with an increased anion-gap type of metabolic acidosis?
Which of the following conditions can cause transient proteinuria?
A long-term diabetic patient is found to have microalbuminuria. What is the typical daily excretion range of albumin in mg/day?
Which intervention should be planned for a patient with renal calculi?
The "half-and-half" nail or "half-nail" sign, seen in uremia, is primarily caused by which of the following?
Nephrology Indian Medical PG Practice Questions and MCQs
Question 471: What are the classic clinical signs suggestive of acute pyelonephritis?
- A. Focal scar in the renal cortex
- B. Septicemia
- C. Altered renal function
- D. Chills, fever, and flank pain (Correct Answer)
Explanation: **Explanation:** **Acute Pyelonephritis** is a clinical diagnosis characterized by an infection of the renal parenchyma and renal pelvis, typically ascending from the lower urinary tract. **1. Why Option D is Correct:** The "Classic Triad" of acute pyelonephritis consists of **fever (usually high-grade), chills/rigors, and flank pain (costovertebral angle tenderness).** These systemic symptoms distinguish upper urinary tract infections (UTI) from lower UTIs (cystitis), which typically present only with localizing symptoms like dysuria, frequency, and urgency. The presence of fever and flank pain indicates that the infection has reached the kidneys, triggering a systemic inflammatory response. **2. Why Other Options are Incorrect:** * **Option A (Focal scar):** This is a radiological finding characteristic of **Chronic Pyelonephritis** or reflux nephropathy, often seen on a DMSA scan. It represents permanent tissue damage rather than acute infection. * **Option B (Septicemia):** While pyelonephritis can lead to urosepsis, septicemia is a *complication* rather than a classic diagnostic sign. Most patients present with localized renal inflammation before progressing to systemic sepsis. * **Option C (Altered renal function):** In unilateral acute pyelonephritis, the unaffected kidney usually maintains normal serum creatinine levels. Significant alteration in renal function suggests bilateral involvement, underlying chronic kidney disease, or obstructive uropathy. **High-Yield Clinical Pearls for NEET-PG:** * **Most common organism:** *E. coli* (followed by *Klebsiella* and *Proteus*). * **Gold Standard Investigation:** Urine culture (reveals significant bacteriuria). * **Urinalysis:** Look for **WBC casts**, which are pathognomonic for pyelonephritis (distinguishes it from cystitis). * **Imaging:** Not routinely required unless the patient is diabetic, immunocompromised, or fails to respond to antibiotics within 72 hours (to rule out perinephric abscess or obstruction).
Question 472: Pre-Renal Azotemia is characterized by all of the following findings, EXCEPT:
- A. Fractional Excretion of Sodium (FeNa) < 1%
- B. Urinary osmolality > 500 mosm/kg
- C. Urinary sodium concentration > 40 meq/L (Correct Answer)
- D. Reversible with replacement fluids
Explanation: **Explanation:** Pre-renal azotemia is a state of renal hypoperfusion (e.g., dehydration, hemorrhage, or heart failure) where the kidney's structural integrity is intact, but the glomerular filtration rate (GFR) is reduced [1]. [2] **Why Option C is the correct answer (The Exception):** In pre-renal states, the kidneys respond to hypoperfusion by activating the Renin-Angiotensin-Aldosterone System (RAAS). Aldosterone acts on the distal tubules to maximize sodium reabsorption to expand intravascular volume [3]. Consequently, the **Urinary Sodium concentration is typically LOW (< 20 mEq/L)**. A urinary sodium > 40 mEq/L is characteristic of **Acute Tubular Necrosis (ATN)**, where tubular damage prevents the kidney from reabsorbing sodium. **Analysis of Incorrect Options:** * **Option A (FeNa < 1%):** This is the most sensitive index for pre-renal azotemia. It indicates that the tubules are functioning perfectly and are avidly conserving sodium. * **Option B (Urinary Osmolality > 500 mOsm/kg):** In response to hypovolemia, ADH (Vasopressin) is secreted, causing the kidneys to reabsorb water and produce highly concentrated urine [1]. * **Option D (Reversible with fluids):** By definition, pre-renal azotemia is a functional abnormality. Restoring renal perfusion with IV fluids or blood quickly corrects the GFR and normalizes creatinine [2]. **High-Yield Clinical Pearls for NEET-PG:** * **BUN/Creatinine Ratio:** In pre-renal azotemia, the ratio is typically **> 20:1** (due to increased passive reabsorption of urea). * **Urine Sediment:** Usually shows **normal or hyaline casts** in pre-renal states, whereas **muddy brown granular casts** are seen in ATN. * **Fractional Excretion of Urea (FeUrea):** Useful if the patient is on diuretics; a **FeUrea < 35%** suggests a pre-renal etiology.
Question 473: What is the mechanism of hypokalemia in Gitelman syndrome?
- A. Mineralocorticoid excess (Correct Answer)
- B. Apparent mineralocorticoid excess
- C. Distal delivery of non-reabsorbed anions
- D. Magnesium deficiency
Explanation: ### Explanation **Mechanism of Hypokalemia in Gitelman Syndrome** Gitelman syndrome is an autosomal recessive tubulopathy caused by a mutation in the **SLC12A3 gene**, leading to the loss of function of the **Thiazide-sensitive Sodium-Chloride (Na-Cl) cotransporter** in the Distal Convoluted Tubule (DCT). The primary mechanism for hypokalemia is **Secondary Hyperaldosteronism (Mineralocorticoid Excess)**. When the Na-Cl cotransporter fails, there is decreased sodium reabsorption in the DCT. This leads to: 1. **Volume Depletion:** Reduced sodium reabsorption triggers the Renin-Angiotensin-Aldosterone System (RAAS) [1]. 2. **Increased Distal Sodium Delivery:** The unabsorbed sodium reaches the Collecting Duct. 3. **Aldosterone Action:** Elevated aldosterone acts on the Principal cells of the collecting duct to reabsorb this excess sodium in exchange for **Potassium (K+) and Hydrogen (H+) ions** via the ROMK channels and H+-ATPase [1]. This results in profound hypokalemia and metabolic alkalosis [1]. **Analysis of Incorrect Options:** * **B. Apparent Mineralocorticoid Excess (AME):** This is due to a deficiency of 11β-HSD2 enzyme (allowing cortisol to act on mineralocorticoid receptors). It presents with hypertension, whereas Gitelman syndrome presents with low/normal blood pressure. * **C. Distal delivery of non-reabsorbed anions:** This is the mechanism for hypokalemia in Type 2 (Proximal) RTA (bicarbonaturia) or vomiting (bicarbonate delivery), not the primary driver in Gitelman. * **D. Magnesium deficiency:** While Gitelman syndrome is characterized by **hypomagnesemia** (unlike Bartter syndrome), and low magnesium can exacerbate potassium wasting, it is a *feature* of the syndrome rather than the primary physiological mechanism for the hypokalemia itself. **High-Yield Clinical Pearls for NEET-PG:** * **Gitelman vs. Bartter:** Gitelman presents later (adolescence/adulthood) and features **Hypocalciuria** and **Hypomagnesemia**. * **Mnemonic:** Gitelman is like chronic **Thiazide** use; Bartter is like chronic **Loop diuretic** use. * **Metabolic Profile:** Hypokalemic Metabolic Alkalosis with Normal/Low Blood Pressure [1].
Question 474: A 43-year-old woman develops acute renal failure following an emergency resection of a leaking abdominal aortic aneurysm. Three days after surgery, the following laboratory values are obtained: Serum electrolytes (mEq/L): Na+:127; K+:5.9; Cl-:92; HCO3-:15. Blood urea nitrogen: 82 mg/dL. Serum creatinine: 6.7 mg/dL. The patient has gained 4 kg since surgery and is mildly dyspneic at rest. Eight hours after these values are reported, an electrocardiogram shows peaked T waves. What is the initial treatment for this patient?
- A. 10% calcium gluconate, 10 mL (Correct Answer)
- B. Digoxin, 0.25 mg every 3 h for three doses
- C. Oral Kayexalate
- D. Lidocaine, 100 mg
Explanation: ### Explanation The patient is presenting with **Acute Kidney Injury (AKI)** post-surgery, complicated by severe **hyperkalemia** (K+ 5.9 mEq/L) and symptomatic **ECG changes (peaked T waves)**. **1. Why Option A is Correct:** The presence of ECG changes in the setting of hyperkalemia is a **medical emergency** [1]. The immediate priority is to stabilize the cardiac myocyte membrane to prevent life-threatening arrhythmias (like ventricular fibrillation or asystole). **Intravenous Calcium Gluconate** (10% solution, 10 mL) acts within 1–3 minutes to antagonize the membrane effects of hyperkalemia [1]. It does *not* lower serum potassium levels but provides a "cardioprotective" window while other measures are initiated to shift or remove potassium. **2. Why Other Options are Incorrect:** * **Option B (Digoxin):** Digoxin is contraindicated here. Hyperkalemia can worsen heart block, and conversely, Digoxin inhibits the Na+/K+-ATPase pump, which can further increase extracellular potassium. * **Option C (Oral Kayexalate):** Sodium polystyrene sulfonate (Kayexalate) is a cation-exchange resin used to remove potassium from the body via the GI tract. However, its onset of action is very slow (hours to days), making it inappropriate for emergency stabilization when ECG changes are present. * **Option D (Lidocaine):** Lidocaine is an anti-arrhythmic used for ventricular tachycardia but does not address the underlying cause (hyperkalemia) or stabilize the membrane against potassium-induced toxicity. **3. NEET-PG High-Yield Pearls:** * **ECG Progression in Hyperkalemia:** Peaked T waves → PR prolongation/P wave flattening → QRS widening → "Sine wave" pattern → Asystole. * **Management Sequence:** 1. **Stabilize:** Calcium Gluconate (Cardioprotection) [1]. 2. **Shift:** Insulin + Dextrose, Beta-2 agonists, or Sodium Bicarbonate (drives K+ intracellularly). 3. **Remove:** Loop diuretics, Resins, or **Hemodialysis** (the definitive treatment in renal failure). * **Note:** In patients on Digoxin, use Calcium Gluconate with extreme caution (or use Calcium Chloride) as it may precipitate "stone heart."
Question 475: Which drug can be used in patients of cardio-renal syndrome?
- A. Insulin (Correct Answer)
- B. NSAIDS
- C. ACEI
- D. ARB
Explanation: ### Explanation **Correct Option: A (Insulin)** In the context of **Cardio-Renal Syndrome (CRS)**, patients often present with acute decompensated heart failure and worsening renal function. This state frequently leads to **Hyperkalemia** (due to reduced GFR and often the use of RAAS inhibitors). **Insulin** is a standard emergency treatment for hyperkalemia [1]. It works by stimulating the **Na+/K+-ATPase pump** in skeletal muscle and liver cells, causing a shift of potassium from the extracellular fluid into the intracellular compartment. In CRS management, insulin (usually given with dextrose to prevent hypoglycemia) is a safe and effective way to manage electrolyte imbalances without further compromising hemodynamics or renal perfusion. [1] **Why other options are incorrect:** * **NSAIDS (Option B):** These are strictly contraindicated in CRS. They inhibit prostaglandins, leading to afferent arteriolar vasoconstriction, which further reduces GFR and promotes sodium/water retention, exacerbating both heart and kidney failure. * **ACE Inhibitors & ARBs (Options C & D):** While these are cornerstones of chronic heart failure management, they are often **withheld or used with extreme caution** in acute cardio-renal syndrome [2]. They cause efferent arteriolar vasodilation, which can lead to a precipitous drop in GFR and worsen hyperkalemia in an already unstable patient [2]. **Clinical Pearls for NEET-PG:** * **Definition:** CRS involves a complex pathophysiology where dysfunction in one organ (heart or kidney) leads to acute or chronic dysfunction in the other. * **Management Priority:** The primary goal in CRS is decongestion (usually via loop diuretics). If hyperkalemia occurs during aggressive diuresis or due to renal failure, **Insulin + Glucose** is the rapid-acting "shift" therapy of choice [1]. * **High-Yield Fact:** Always monitor for **hypoglycemia** when using insulin for hyperkalemia, especially in patients with renal failure, as the half-life of insulin is prolonged.
Question 476: Which of the following conditions is NOT associated with an increased anion-gap type of metabolic acidosis?
- A. Shock
- B. Ingestion of antifreeze
- C. Diabetic ketoacidosis
- D. COPD (Correct Answer)
Explanation: **Explanation:** The core concept tested here is the classification of acid-base disorders [2]. Metabolic acidosis is categorized based on the **Anion Gap (AG)**, calculated as $[Na^+] - ([Cl^-] + [HCO_3^-])$. An increased AG indicates the presence of unmeasured anions (organic acids). **Why COPD is the correct answer:** Chronic Obstructive Pulmonary Disease (COPD) causes **Respiratory Acidosis**, not metabolic acidosis [2]. In COPD, alveolar hypoventilation leads to the retention of carbon dioxide ($CO_2$), resulting in hypercapnia. While the body may compensate by increasing bicarbonate ($HCO_3^-$) levels via the kidneys, the primary pathology is respiratory [1]. It does not involve the accumulation of fixed metabolic acids that would increase the anion gap. **Analysis of Incorrect Options (Causes of High AG Metabolic Acidosis):** * **Shock (Option A):** Leads to tissue hypoperfusion and anaerobic metabolism, resulting in the accumulation of **Lactic Acid** [1]. * **Ingestion of Antifreeze (Option B):** Ethylene glycol is metabolized into toxic acids like **glycolic and oxalic acid**, which significantly raise the anion gap. * **Diabetic Ketoacidosis (Option C):** Insulin deficiency leads to the production of ketoacids (**beta-hydroxybutyrate and acetoacetate**), which are unmeasured anions. **NEET-PG High-Yield Pearls:** * **Mnemonic for High AG Metabolic Acidosis:** **MUDPILES** (Methanol, Uremia, DKA, Propylene glycol, Iron/INH, Lactic acidosis, Ethylene glycol, Salicylates). * **Normal AG Metabolic Acidosis (NAGMA):** Primarily caused by GI loss of $HCO_3^-$ (Diarrhea) or renal loss (Renal Tubular Acidosis) [1]. * **Golden Rule:** In any case of metabolic acidosis, always calculate the Anion Gap first to narrow the differential diagnosis.
Question 477: Which of the following conditions can cause transient proteinuria?
- A. Fever
- B. Dehydration
- C. Heavy exercise
- D. All of the above (Correct Answer)
Explanation: **Explanation:** **Transient proteinuria** (also known as functional proteinuria) is a benign, self-limiting condition characterized by a temporary increase in urinary protein excretion in the absence of underlying structural renal disease. It is the most common cause of proteinuria in children and young adults. **Why the correct answer is "All of the above":** The underlying mechanism involves hemodynamic changes in the kidney [3]. Stressors cause alterations in renal blood flow and increased glomerular capillary pressure, leading to a temporary "leakage" of proteins (primarily albumin) across the glomerular basement membrane. * **Fever (Option A):** High body temperature increases metabolic demand and alters glomerular permeability. * **Dehydration (Option B):** Reduced intravascular volume leads to renal vasoconstriction and sluggish blood flow, which can concentrate proteins in the filtrate. * **Heavy Exercise (Option C):** Intense physical activity triggers sympathetic nervous system activation and the renin-angiotensin system, causing transient renal vasoconstriction and increased glomerular pressure [2]. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Transient proteinuria is diagnosed when a follow-up urinalysis (usually after 24–48 hours of rest or resolution of the stressor) is **negative** for protein. * **Quantification:** It typically results in less than 1 gram of protein per day. * **Orthostatic (Postural) Proteinuria:** Another benign variant where protein is present only when the patient is upright [3]. It is diagnosed using a **split-urine collection** (day vs. night). * **Management:** No specific treatment or renal biopsy is required for transient proteinuria; reassurance is the mainstay of management. * **Rule of Thumb:** Persistent proteinuria (detected on two or more occasions) always warrants further investigation for glomerular or tubular disease [1].
Question 478: A long-term diabetic patient is found to have microalbuminuria. What is the typical daily excretion range of albumin in mg/day?
- A. 100 - 150 mg/day
- B. 30 - 300 mg/day (Correct Answer)
- C. 201 - 300 mg/day
- D. 301 - 600 mg/day
Explanation: **Explanation:** Microalbuminuria is the earliest clinical sign of **Diabetic Nephropathy** and represents a level of albumin excretion that is higher than normal but below the detection limit of a standard urine dipstick [1]. 1. **Why Option B is Correct:** The standard clinical definition of microalbuminuria is a persistent albumin excretion rate of **30–300 mg/day** (measured via 24-hour urine collection). On a random spot urine sample, this corresponds to an **Albumin-to-Creatinine Ratio (ACR) of 30–300 mg/g**. This range indicates early glomerular damage where the basement membrane's charge selectivity is compromised [2], but the damage is still potentially reversible with strict glycemic and blood pressure control (specifically using ACE inhibitors or ARBs). 2. **Why Other Options are Incorrect:** * **Option A (100–150 mg/day):** This is a subset of the microalbuminuria range but does not define its lower or upper limits. * **Option C (201–300 mg/day):** This represents "high-range" microalbuminuria, often seen just before progressing to overt nephropathy. * **Option D (301–600 mg/day):** Excretion **>300 mg/day** is classified as **Macroalbuminuria** (Overt Nephropathy or Clinical Albuminuria). At this stage, the urine dipstick becomes positive for protein. **High-Yield Clinical Pearls for NEET-PG:** * **Screening:** Type 1 Diabetics should be screened 5 years after diagnosis; Type 2 Diabetics should be screened **at the time of diagnosis** [1]. * **Gold Standard:** 24-hour urine collection is the gold standard, but **Spot Morning ACR** is the preferred screening method due to convenience. * **Diagnosis:** Requires at least **2 out of 3** positive specimens over a 3-to-6-month period. * **Management:** ACE inhibitors or ARBs are the drugs of choice as they reduce intraglomerular pressure by dilating the efferent arteriole.
Question 479: Which intervention should be planned for a patient with renal calculi?
- A. Maintain bed rest
- B. Increase dietary purines
- C. Restrict fluids
- D. Strain all urine (Correct Answer)
Explanation: **Explanation:** The primary goal in the management of acute renal calculi (nephrolithiasis) is the identification of the stone's composition to guide long-term prevention. [1] **Why "Strain all urine" is correct:** Straining all urine is the most critical nursing and diagnostic intervention. It allows for the physical recovery of the stone or its fragments as they pass through the urethra. Once captured, the stone undergoes **chemical analysis** to determine its type (e.g., Calcium oxalate, Uric acid, Struvite, or Cystine). [1] This analysis is the "gold standard" for tailoring dietary and pharmacological interventions to prevent recurrence. **Analysis of Incorrect Options:** * **A. Maintain bed rest:** Immobility actually promotes urinary stasis and bone demineralization (increasing hypercalciuria), which can worsen stone formation. Patients are encouraged to **ambulate**, as gravity and movement help the stone migrate down the ureter. * **B. Increase dietary purines:** High purine intake (found in red meats and organ meats) increases uric acid levels, leading to **uric acid stones**. Patients with calculi are generally advised to reduce purine intake. [2] * **C. Restrict fluids:** This is contraindicated. Low urine volume is a major risk factor for crystallization. Patients should **increase fluid intake** (aiming for >2.5L urine output/day) to decrease the concentration of calculogenic salts. **Clinical Pearls for NEET-PG:** * **Most common stone:** Calcium Oxalate (Radiopaque; Envelope/Dumbbell shaped). * **Staghorn calculi:** Associated with *Proteus* infections (Urease positive) and composed of **Struvite** (Magnesium Ammonium Phosphate). [3] * **Medical Expulsive Therapy (MET):** Alpha-blockers (e.g., **Tamsulosin**) are used to relax distal ureteral smooth muscle to facilitate stone passage. [1] * **Dietary advice:** Contrary to intuition, a **normal calcium diet** is preferred over a low-calcium diet to prevent increased oxalate absorption in the gut.
Question 480: The "half-and-half" nail or "half-nail" sign, seen in uremia, is primarily caused by which of the following?
- A. Melanin deposition in the nail bed
- B. Increased capillary density in the proximal half of the nail bed (Correct Answer)
- C. Hypoproteinemia leading to edema
- D. Accumulation of circulating toxins affecting nail matrix
Explanation: **Explanation:** **Half-and-half nails (Lindsay’s nails)** are a characteristic clinical finding in patients with chronic kidney disease (CKD) and uremia. The nail is divided into a proximal white/opaque half and a distal red, pink, or brown band (occupying 20–50% of the nail) [1]. 1. **Why the correct answer is right:** The distal brownish-red discoloration is not due to pigment deposition in the nail plate itself, but rather changes in the underlying nail bed. Histopathological studies show that this is caused by **increased capillary density** and thickening of the capillary walls in the distal portion of the nail bed. Additionally, there is an accumulation of connective tissue (melanocyte-stimulating hormone has also been implicated, but the primary vascular change is the hallmark). 2. **Why the incorrect options are wrong:** * **Option A:** Melanin deposition is seen in longitudinal melanonychia (often drug-induced or due to Addison’s disease), not typically in uremic nails. * **Option C:** Hypoproteinemia causes **Muehrcke’s lines** (paired white transverse bands) [1]. These are "apparent leukonychia" caused by localized dermal edema, not increased vascularity. * **Option D:** While uremic toxins affect many systems, the specific "half-and-half" morphology is a result of localized vascular and connective tissue changes rather than a direct toxic effect on the nail matrix (which would more likely cause Beau’s lines) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Lindsay’s Nails:** Half-and-half nails (20-50% distal band); specific for **Uremia/CKD** [1]. * **Terry’s Nails:** Most of the nail is white with a very narrow distal pink band (only 1-2 mm); classically associated with **Liver Cirrhosis**. * **Muehrcke’s Lines:** Transverse white bands that disappear with pressure; associated with **Hypoalbuminemia** (e.g., Nephrotic syndrome) [1]. * **Beau’s Lines:** Transverse depressions/grooves in the nail plate; indicates a temporary cessation of **nail matrix** growth due to severe systemic illness [1].
Practice by Chapter
Acute Kidney Injury
Practice Questions
Chronic Kidney Disease
Practice Questions
Glomerular Diseases
Practice Questions
Tubulointerstitial Diseases
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Nephrotic and Nephritic Syndromes
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Urinary Tract Infections
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Renal Replacement Therapy
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Fluid and Electrolyte Disorders
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Acid-Base Disorders
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Kidney in Systemic Diseases
Practice Questions
Kidney Stones and Obstructive Uropathy
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Hypertension in Kidney Disease
Practice Questions
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