Nephrology Practice Questions

Q: A 25-year-old man has IDDM for 5 years. Which is the best early indicator for diabetic nephropathy?

Albuminuria. **Explanation:** The earliest clinical hallmark of diabetic nephropathy (DN) is **Albuminuria**, specifically **Microalbuminuria** (defined as 30–300 mg/day) [1]. In patients with Type 1 Diabetes (IDDM), this typically manifests after 5 years of disease duration. **Why Albuminuria is the correct answer:** Hyperglycemia leads to non-enzymatic glycosylation of the glomerular basement membrane and efferent arteriolar vasoconstriction. This causes glomerular hyperfiltration and increased intraglomerular pressure, leading to the leakage of small amounts of albumin [1]. It precedes any decline in GFR or rise in nitrogenous waste, making it the most sensitive early screening tool [2]. **Why other options are incorrect:** * **Hypertension:** While hypertension is a key feature of DN, it usually develops concurrently with or after the onset of albuminuria. It is a consequence of renal damage rather than the earliest indicator. * **Rising Blood Urea Nitrogen (BUN) & Rising Creatinine:** These are markers of advanced renal dysfunction (decreased GFR). By the time these values rise, significant irreversible structural damage (Kimmelstiel-Wilson nodules) has already occurred [2]. They are late indicators, not early ones. **High-Yield Clinical Pearls for NEET-PG:** 1. **Natural History:** The stages of DN are: Hyperfiltration → Silent Phase (Thickened GBM) → **Microalbuminuria (Earliest clinical sign)** → Macroalbuminuria (Overt Nephropathy) → ESRD [2]. 2. **Screening:** In IDDM, screen for albuminuria 5 years after diagnosis. In NIDDM (Type 2), screen at the time of diagnosis. 3. **Pathology:** The most specific histological finding is **Kimmelstiel-Wilson (KW) nodules** (nodular glomerulosclerosis) [2]. 4. **Management:** ACE inhibitors or ARBs are the drugs of choice as they reduce intraglomerular pressure by dilating the efferent arteriole.

Q: What is the most common cause of nephrotic syndrome in elderly patients?

Membranous glomerulonephritis. **Explanation:** **Membranous Nephropathy (MN)**, also known as Membranous Glomerulonephritis, is the most common cause of primary nephrotic syndrome in the elderly population (typically defined as >60 years). Pathologically, it is characterized by the thickening of the glomerular basement membrane due to the deposition of immune complexes (IgG and C3) in the subepithelial space, leading to a "spike and dome" appearance on electron microscopy [1]. In elderly patients, a significant proportion (up to 25%) of MN cases are **secondary**, most commonly associated with underlying **malignancies** (solid tumors of the lung, colon, or breast). **Analysis of Incorrect Options:** * **Minimal Change Disease (MCD):** This is the most common cause of nephrotic syndrome in **children**. While it can occur in adults, it is less frequent than MN in the elderly [1]. * **IgA Nephropathy:** This is the most common cause of **primary glomerulonephritis** worldwide, but it typically presents as **nephritic syndrome** (recurrent hematuria) in young adults, rather than pure nephrotic syndrome in the elderly [1]. * **Focal Segmental Glomerulosclerosis (FSGS):** Though not listed as a primary option, it is the most common cause of nephrotic syndrome in **young adults** and African Americans. **High-Yield Clinical Pearls for NEET-PG:** * **Primary MN:** 70-80% of cases are associated with antibodies against the **Phospholipase A2 Receptor (PLA2R)**. * **Secondary MN:** Always rule out malignancy, SLE, Hepatitis B, and drugs (NSAIDs, Gold, Penicillamine) in elderly patients. * **Complication:** MN has the highest risk of **renal vein thrombosis** among all nephrotic syndromes. * **Rule of Thumb:** Children = MCD; Young Adults = FSGS; Elderly = MN.

Q: A patient undergoing hemodialysis complains of muscle cramps. Which intervention is effective in relieving muscle cramps?

Infuse normal saline solution. ### Explanation **Correct Option: B (Infuse normal saline solution)** Muscle cramps are one of the most common complications of hemodialysis [1], typically occurring due to **hypovolemia** and **hypotension** caused by rapid fluid removal (ultrafiltration). When the intravascular volume is depleted, it leads to muscle hypoperfusion and electrolyte shifts across the cell membrane, triggering involuntary contractions. Infusing a bolus of **Normal Saline (0.9% NaCl)** or hypertonic saline increases the plasma osmolality and intravascular volume [2], which improves muscle perfusion and rapidly alleviates the cramp. **Analysis of Incorrect Options:** * **A. Increase the rate of dialysis:** This would accelerate fluid removal and solute clearance, likely worsening hypotension and exacerbating muscle cramps. * **C. Administer a 5% dextrose solution:** Dextrose 5% (D5W) is an isotonic solution that becomes hypotonic once the glucose is metabolized [2]. It does not stay in the intravascular space effectively and can lead to hyposmolality, which may actually trigger or worsen cramps. * **D. Active range of motion exercises:** While passive stretching of the affected muscle can provide temporary relief, active exercise during a dialysis-induced hypotensive episode is impractical and does not address the underlying volume deficit. **Clinical Pearls for NEET-PG:** * **Most common cause of cramps in HD:** Excessive or rapid ultrafiltration (hypovolemia). * **Prevention:** Accurate assessment of "dry weight," reducing sodium modeling, and avoiding heavy meals during dialysis. * **First-line management:** Reducing the ultrafiltration rate to zero and administering a 100–200 mL bolus of Normal Saline. * **Alternative treatment:** Hypertonic solutions (e.g., 23.4% saline or 50% dextrose) can be used as they create an osmotic shift of fluid into the intravascular space.

Q: An 18-year-old student presents with dark urine, fever, and flank pain, and is diagnosed with acute glomerulonephritis. What is the most likely preceding event in this student's health history?

Recent sore throat. ### Explanation The clinical presentation of dark urine (hematuria), fever, and flank pain in a young patient is classic for **Post-Streptococcal Glomerulonephritis (PSGN)**. This is a Type III hypersensitivity reaction occurring after an infection with nephritogenic strains of Group A Beta-hemolytic *Streptococcus* (GABHS). **Why "Recent sore throat" is correct:** PSGN typically follows a **pharyngeal infection** (sore throat) or a **skin infection** (impetigo). There is a characteristic latent period between the infection and the onset of renal symptoms: 1–3 weeks after pharyngitis and 3–6 weeks after pyoderma. The deposition of immune complexes in the glomerular basement membrane leads to the "lumpy-bumpy" appearance on immunofluorescence and the classic "coke-colored" or smoky urine [1]. **Why the other options are incorrect:** * **Renal calculi:** While stones cause flank pain and hematuria, they do not typically cause the systemic inflammatory features of glomerulonephritis (like RBC casts or significant proteinuria) unless complicated by obstructive pyelonephritis. * **Renal trauma:** This would cause gross hematuria and pain immediately following an injury, not a systemic nephritic syndrome. * **Family history:** While some nephropathies (like Alport syndrome) are hereditary, the acute onset following a febrile illness strongly points toward an infectious trigger rather than a genetic predisposition [1]. **NEET-PG High-Yield Pearls:** * **Most common cause** of acute nephritic syndrome in children/young adults worldwide. * **Lab findings:** Low C3 levels (complement consumption) and elevated ASO titers (after pharyngitis) or Anti-DNAse B (after skin infection). * **Light Microscopy:** "Starry sky" appearance or "Lumpy-bumpy" deposits of IgG and C3. * **Electron Microscopy:** Subepithelial "humps." * **Prognosis:** Excellent in children (95% recover), but more guarded in adults.

Q: Prominent U waves on the ECG is a feature of which of the following conditions?

Hypokalemia. **Explanation:** The correct answer is **Hypokalemia (Option C)**. **1. Why Hypokalemia is Correct:** Potassium is the primary intracellular cation responsible for the repolarization phase of the cardiac action potential. In hypokalemia (serum $K^+ < 3.5$ mEq/L), the resting membrane potential becomes more negative, and the duration of the action potential is prolonged. This delay in ventricular repolarization manifests on the ECG as: * **Prominent U waves:** A positive wave following the T wave (most characteristic). * **Flattening or inversion of T waves.** * **ST-segment depression.** * **Prolonged PR interval.** **2. Why the Other Options are Incorrect:** * **Hyperkalemia (Option D):** Characterized by "Tall Peaked T waves" (earliest sign), followed by loss of P waves, QRS widening, and eventually a "Sine wave" pattern leading to asystole. * **Hyponatremia and Hypernatremia (Options A & B):** Sodium imbalances primarily affect neurological status (cerebral edema or shrinkage) and volume status. They do not typically produce specific, diagnostic ECG changes like potassium imbalances do. **3. High-Yield Clinical Pearls for NEET-PG:** * **U wave origin:** Likely represents delayed repolarization of the Purkinje fibers or Mid-myocardial (M) cells. * **Hypomagnesemia:** Often co-exists with hypokalemia and can also cause U waves and Torsades de Pointes. * **Mnemonic for Hypokalemia ECG:** "6 **L**'s" — **L**ow T wave, **L**ine depressed (ST), **L**ong PR, **L**ethal ventricular arrhythmias, **L**arge U wave, **L**ax muscles (weakness). * **Digitalis toxicity:** Can also cause U waves, but usually alongside a "scooped" ST segment.

Q: All of the following infections have a well-recognized association with nephropathies except?

Hepatitis A. **Explanation:** The association between systemic infections and glomerular diseases is a high-yield topic in Nephrology. The correct answer is **Hepatitis A**, as it is primarily an acute, self-limiting infection and is **not** typically associated with chronic immune-complex mediated nephropathies [2]. **1. Why Hepatitis A is the correct answer:** Unlike Hepatitis B and C, which are notorious for causing chronic infections and subsequent glomerular damage (like Membranous Nephropathy or Cryoglobulinemic Vasculitis), Hepatitis A does not lead to chronicity [2]. While rare cases of transient acute kidney injury (AKI) due to ATN or interstitial nephritis have been reported, it lacks a "well-recognized" association with specific nephropathies. **2. Analysis of incorrect options:** * **Staphylococcus epidermidis:** Well-recognized for causing **"Shunt Nephritis."** This occurs when infected ventriculoatrial shunts lead to chronic antigenemia and immune-complex deposition in the glomeruli (MPGN pattern) [1]. * **Salmonella typhi:** Associated with **Glomerulonephritis** during the course of typhoid fever. It can present with proteinuria and hematuria due to immune-complex deposition in the mesangium. * **Legionnaire's disease:** Frequently associated with renal involvement, most commonly **Acute Tubular Necrosis (ATN)** or tubulointerstitial nephritis, often presenting with microscopic hematuria and proteinuria. **Clinical Pearls for NEET-PG:** * **Hepatitis B:** Most commonly associated with **Membranous Nephropathy (MGN)** and Polyarteritis Nodosa (PAN). * **Hepatitis C:** Most strongly associated with **Type I MPGN** and **Mixed Cryoglobulinemia** [2]. * **HIV:** Classically associated with **Collapsing variant of FSGS** (HIVAN) [1]. * **Syphilis:** A classic infectious cause of Membranous Nephropathy.

Q: A 21-year-old woman presents with a 2-day history of abdominal pain, nausea, and vomiting. On examination, her blood pressure is 100/70 mmHg, pulse 100/min, JVP is below sternal angle, and abdomen is diffusely tender. Her urine output is low and electrolytes reveal elevated urea and normal creatinine. For the above patient with AKI, what are the characteristic urine electrolyte and microscopy findings?

Urinary sodium 20:1** (elevated urea with normal/near-normal creatinine), indicating that the kidneys are structurally intact but responding to decreased perfusion [1]. **1. Why Option C is Correct:** In prerenal states, the kidneys attempt to restore intravascular volume by maximizing sodium and water reabsorption. The intact tubular function allows for the activation of the Renin-Angiotensin-Aldosterone System (RAAS), leading to: * **Urinary Sodium 500 mOsm/kg)** as the kidneys concentrate urine to conserve water [1]. **2. Why the Other Options are Incorrect:** * **Option A:** Urinary osmolality 500 mOsm/kg) [1]. * **Option B:** Oxalate crystals are characteristic of ethylene glycol poisoning or secondary to high-dose Vitamin C. They are not a feature of volume-depletion-induced prerenal AKI. * **Option D:** FeNa > 1% (and often > 2%) is characteristic of **Acute Tubular Necrosis (ATN)**, where tubular damage prevents the kidney from reabsorbing sodium. **Clinical Pearls for NEET-PG:** * **Prerenal AKI:** FeNa 500, Hyaline casts [1]. * **Intrinsic AKI (ATN):** FeNa > 1%, UNa > 40, Urine Osmolality < 350, **Muddy brown granular casts** [2]. * **Exception:** FeNa can be < 1% in certain intrinsic causes like Contrast-induced nephropathy and Acute Glomerulonephritis.

Question 1

What is the drug of choice for stage I hypertension with diabetic nephropathy associated with frank proteinuria?

Accepted Answer

ACE inhibitor

Answer

Alpha blocker

Answer

Beta blocker

Answer

Calcium channel blocker

Question 2

A 25-year-old man has IDDM for 5 years. Which is the best early indicator for diabetic nephropathy?

Accepted Answer

Albuminuria

Answer

Hypertension

Answer

Rising blood urea nitrogen

Answer

Rising creatinine

Question 3

What is the most common cause of nephrotic syndrome in elderly patients?

Accepted Answer

Membranous glomerulonephritis

Answer

Minimal change glomerulonephritis

Answer

IgA nephropathy

Answer

None of the above

Question 4

A patient undergoing hemodialysis complains of muscle cramps. Which intervention is effective in relieving muscle cramps?

Accepted Answer

Infuse normal saline solution

Answer

Increase the rate of dialysis

Answer

Administer a 5% dextrose solution

Answer

Encourage active range of motion exercises

Question 5

An 18-year-old student presents with dark urine, fever, and flank pain, and is diagnosed with acute glomerulonephritis. What is the most likely preceding event in this student's health history?

Accepted Answer

Recent sore throat

Answer

Renal calculi

Answer

Renal trauma

Answer

Family history of acute glomerulonephritis

Question 6

Glomerulonephritis associated with sensory neural deafness are features of?

Accepted Answer

Alport's syndrome

Answer

Nail patella syndrome

Answer

Down's syndrome

Answer

Fabry's syndrome

Question 7

Prominent U waves on the ECG is a feature of which of the following conditions?

Accepted Answer

Hypokalemia

Answer

Hyponatremia

Answer

Hypernatremia

Answer

Hyperkalemia

Question 8

All of the following infections have a well-recognized association with nephropathies except?

Accepted Answer

Hepatitis A

Answer

Staphylococcus Epidermidis

Answer

Salmonella Typhi

Answer

Legionnaire's disease

Question 9

A 63-year-old man with a history of alcoholism and smoking presents with fatigue and confusion. Physical examination reveals a blood pressure of 110/70 with no orthostatic change. Laboratory data are as follows: Na: 110 mEq/L, K: 3.7 mEq/L, Cl: 82 mEq/L, HCO3: 20 mEq/L, Glucose: 100 mg/dL, BUN: 5 mg/dL, Creatinine: 0.7 mg/dL, Urinalysis: normal, Urine specific gravity: 1.016. Which of the following is the most likely diagnosis?

Accepted Answer

Inappropriate secretion of antidiuretic hormone

Answer

Volume depletion

Answer

Psychogenic polydipsia

Answer

Cirrhosis

Question 10

A 21-year-old woman presents with a 2-day history of abdominal pain, nausea, and vomiting. On examination, her blood pressure is 100/70 mmHg, pulse 100/min, JVP is below sternal angle, and abdomen is diffusely tender. Her urine output is low and electrolytes reveal elevated urea and normal creatinine. For the above patient with AKI, what are the characteristic urine electrolyte and microscopy findings?

Accepted Answer

Urinary sodium < 20 mEq/L

Answer

Urinary osmolality < 100 mOsm/kg

Answer

Oxalate crystals in the urine

Answer

Fractional sodium excretion > 1%

Nephrology — MCQs

Nephrology — MCQs

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