Nephrology Practice Questions

Q: In which stage of Chronic Kidney Disease is a decrease in Glomerular Filtration Rate (GFR) typically apparent?

Stage II. **Explanation:** The classification of Chronic Kidney Disease (CKD) is based on the **KDIGO guidelines**, which categorize stages according to the Glomerular Filtration Rate (GFR). **Why Stage II is the correct answer:** In **Stage I CKD**, the GFR remains normal or even increased (≥90 mL/min/1.73 m²). The diagnosis at this stage relies on markers of kidney damage (e.g., albuminuria, structural changes). **Stage II CKD** is defined by a **mild decrease in GFR (60–89 mL/min/1.73 m²)**. Therefore, Stage II is the earliest point at which a quantitative decline in GFR becomes apparent and measurable, even if the patient remains asymptomatic. **Analysis of Incorrect Options:** * **Stage I:** GFR is ≥90 mL/min. There is kidney damage, but the filtration rate has not yet decreased. * **Stage III:** Characterized by a moderate decrease in GFR (30–59 mL/min). While the decrease is very evident here, it is not the *first* stage where the decline appears. * **Stage IV:** Characterized by a severe decrease in GFR (15–29 mL/min). This represents advanced disease nearing the need for renal replacement therapy. **High-Yield Clinical Pearls for NEET-PG:** * **Definition of CKD:** Evidence of kidney damage or GFR <60 mL/min for **≥3 months**. * **Stage III Breakdown:** It is often subdivided into **IIIa** (GFR 45–59) and **IIIb** (GFR 30–44). * **Stage V:** Known as End-Stage Renal Disease (ESRD) when GFR is **<15 mL/min**. * **Most Common Cause:** Diabetes Mellitus is the leading cause of CKD worldwide, followed by Hypertension. * **First Sign:** Microalbuminuria is often the earliest clinical sign of diabetic nephropathy, preceding the GFR decline.

Q: Which of the following are treatments for hyperkalemia?

All of the above. Hyperkalemia is a medical emergency defined by serum potassium levels >5.5 mEq/L. Management focuses on three pillars: membrane stabilization, intracellular shifting, and elimination [1]. **Explanation of the Correct Answer:** The correct answer is **D (All of the above)** because each option utilizes the principle of **intracellular shifting**—moving potassium from the extracellular fluid into the cells to rapidly lower plasma levels [2]. * **Intravenous Dextrose (with Insulin):** This is the most reliable method for shifting potassium. Insulin stimulates the Na+-K+ ATPase pump, driving potassium into cells. Dextrose is co-administered to prevent hypoglycemia. * **Parenteral Sodium Bicarbonate:** By increasing systemic pH (alkalosis), it induces an H+/K+ exchange where hydrogen ions leave the cell and potassium ions enter to maintain electroneutrality [2]. It is most effective in patients with underlying metabolic acidosis. * **Albuterol (Beta-2 Agonists):** These stimulate the Na+-K+ ATPase pump via cyclic AMP signaling. Note that the dose required for hyperkalemia is significantly higher (10–20 mg) than the standard dose for asthma. **High-Yield Clinical Pearls for NEET-PG:** 1. **C-BIG-K mnemonic:** **C**alcium gluconate (stabilizes cardiac membrane), **B**icarbonate/Beta-agonists, **I**nsulin + **G**lucose, **K**ayexalate (elimination). 2. **First Step:** If ECG changes (e.g., peaked T-waves, widened QRS) are present, the immediate first step is **IV Calcium Gluconate** [1]. It does *not* lower potassium but protects the heart. 3. **Definitive Treatment:** While the options above shift potassium, **Hemodialysis** is the most effective way to actually remove potassium from the body in refractory cases or renal failure.

Q: Which of the following are causes of anemia in Chronic Kidney Disease (CKD)?

All the above. Anemia in Chronic Kidney Disease (CKD) is typically **normocytic and normochromic**, primarily driven by a multifactorial process [1]. **Explanation of the Correct Answer:** The correct answer is **D (All the above)** because CKD affects red blood cell (RBC) production, lifespan, and nutrient availability: 1. **Erythropoietin (EPO) Deficiency:** This is the **most significant cause**. EPO is produced by the peritubular interstitial cells of the kidney. [2] As renal mass declines, EPO production decreases, leading to reduced bone marrow stimulation. 2. **Decreased Erythrocyte Survival:** The "uremic milieu" (accumulation of toxins like guanidinosuccinic acid) creates a hostile environment for RBCs, leading to increased fragility and premature destruction (hemolysis) [1]. 3. **Nutrient Deficiencies (Folic Acid/Iron):** Patients with CKD often have poor dietary intake. Furthermore, water-soluble vitamins like **folic acid** are lost during the dialysis process. Iron deficiency is also common due to chronic blood loss (GI bleeds, frequent blood sampling) and increased **hepcidin** levels, which block iron absorption and mobilization [2], [3]. **Why other options are considered part of the whole:** Options A, B, and C are all individual contributors. Selecting only one would be incomplete, as the pathogenesis of renal anemia involves the interplay of hormonal deficiency, toxic suppression of the marrow, and nutritional loss [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Target Hemoglobin:** In CKD patients on EPO therapy, the target Hb is **10–11.5 g/dL**. Aiming for >13 g/dL increases the risk of stroke and cardiovascular events (CHOIR and CREATE trials). * **Hepcidin:** This is the "master regulator" of iron. In CKD, inflammation increases hepcidin, leading to **functional iron deficiency** [2]. * **First Step in Management:** Always rule out and treat iron deficiency before starting Erythropoiesis-Stimulating Agents (ESAs).

Q: A patient in the oliguric phase of renal failure is expected to have a 24-hour urine output less than which of the following values?

400ml. ### Explanation **Correct Option: B. 400ml** In clinical nephrology, **Oliguria** is defined as a urine output of less than **400 ml/day** (or <0.5 ml/kg/hour in adults) [1]. This threshold is physiologically significant because it represents the minimum amount of urine required to excrete the average daily load of metabolic waste products (solutes like urea and creatinine), assuming the kidneys are maximally concentrating the urine (approx. 1200 mOsm/L). When output falls below this level, solute accumulation occurs, leading to azotemia. **Analysis of Incorrect Options:** * **A. 200ml:** While 200ml is technically oliguric, it is not the standard diagnostic threshold. Urine output <100 ml/day is specifically defined as **Anuria** [1], which often suggests complete urinary tract obstruction, bilateral renal artery occlusion, or cortical necrosis. * **C. 800ml & D. 1000ml:** These values fall within the range of normal or "non-oliguric" urine output. Patients can still be in acute kidney injury (AKI) with these volumes; this is termed **Non-oliguric AKI** [2] (commonly seen in aminoglycoside toxicity or interstitial nephritis), which generally carries a better prognosis than oliguric AKI. **Clinical Pearls for NEET-PG:** * **Phases of AKI:** 1. Initiation phase, 2. Oliguric phase (maintenance), 3. Polyuric phase (recovery). * **Polyuric Phase:** During recovery, urine output can exceed 3–5 liters/day. The most common cause of death in this phase is **hypokalemia** and dehydration. * **Azotemia vs. Uremia:** Azotemia is the biochemical increase in nitrogenous waste; Uremia is the clinical syndrome resulting from that increase. * **Fractional Excretion of Sodium (FeNa):** In the oliguric phase of Prerenal AKI, FeNa is 2%.

Q: A 21-year-old female presents with a history of brown-colored urine that occurred approximately two months prior, lasting for about three days, following a cold. Currently, urinalysis shows blood with red cells and red cell casts. Further laboratory tests, including CBC, serum electrolytes, BUN, creatinine, glucose, ANAs, and serum complement levels (C3 and C4), are all within normal limits. Immunofluorescence examination of a renal biopsy reveals large, irregular deposits of IgA/C3 in the mesangium, with no linear staining pattern. What is the most likely diagnosis for this patient?

Berger's disease. **Explanation:** The clinical presentation is classic for **Berger’s disease (IgA Nephropathy)**, the most common primary glomerulonephritis worldwide. **Why Berger’s Disease is Correct:** 1. **Synpharyngitic Hematuria:** The history of brown-colored urine occurring shortly (within 1-2 days) after an upper respiratory tract infection ("a cold") is a hallmark [1]. This contrasts with Post-Streptococcal Glomerulonephritis (PSGN), which has a longer latent period (1-3 weeks) [1]. 2. **Normal Complements:** Unlike PSGN or Lupus Nephritis, serum C3 and C4 levels remain **normal** in IgA Nephropathy. 3. **Biopsy Findings:** Immunofluorescence showing **granular, irregular IgA and C3 deposits** restricted to the **mesangium** is the gold-standard diagnostic feature [1]. **Why Other Options are Incorrect:** * **Focal Segmental Glomerulosclerosis (FSGS):** Typically presents with nephrotic syndrome (heavy proteinuria). Biopsy shows segmental sclerosis in some glomeruli, not mesangial IgA deposits. * **Goodpasture’s Disease:** Characterized by anti-GBM antibodies. Immunofluorescence shows a **smooth, linear IgG staining** pattern along the glomerular basement membrane, not irregular mesangial IgA [1]. It often involves pulmonary hemorrhage. * **Lipoid Nephrosis (Minimal Change Disease):** The most common cause of nephrotic syndrome in children. Light microscopy and immunofluorescence are typically negative; diagnosis requires electron microscopy to see podocyte effacement. **High-Yield Pearls for NEET-PG:** * **Most common** primary GN worldwide: IgA Nephropathy. * **Henoch-Schönlein Purpura (HSP):** The systemic version of IgA nephropathy (presents with rash, joint pain, and abdominal pain). * **Prognosis:** Persistent proteinuria (>1g/day) and hypertension are the strongest predictors of progression to ESRD [1]. * **Association:** Often associated with Celiac disease and liver cirrhosis (decreased clearance of IgA complexes).

Q: Which of the following is NOT a feature of acute glomerulonephritis?

Polyuria. **Explanation:** Acute Glomerulonephritis (AGN) is characterized by the **Nephritic Syndrome**, a clinical triad resulting from acute glomerular inflammation [1]. This inflammation leads to a sudden decline in the Glomerular Filtration Rate (GFR), which triggers the classic presentation. **Why Polyuria is the correct answer:** Polyuria (increased urine output) is **not** a feature of AGN. In fact, the pathophysiology of AGN involves glomerular capillary clogging by inflammatory cells and mesangial proliferation [1]. This significantly reduces the GFR, leading to salt and water retention. Consequently, patients present with **Oliguria** (urine output <400 ml/day), not polyuria [2]. Polyuria is more commonly associated with the recovery phase of acute tubular necrosis, diabetes mellitus, or diabetes insipidus. **Analysis of incorrect options:** * **B. Hematuria:** This is the hallmark of nephritic syndrome [1]. Glomerular injury allows RBCs to leak into the Bowman’s space, often resulting in "smoky" or "cola-colored" urine [2]. * **C. Red cell casts:** These are highly specific for glomerular bleeding. When RBCs pass through the nephron, they are trapped in a matrix of Tamm-Horsfall protein in the distal tubules, forming casts. Their presence confirms the kidney as the source of hematuria. * **D. Oliguria:** As explained, the reduction in GFR and compensatory fluid retention lead to decreased urine output, which is a core component of the nephritic presentation [2]. **High-Yield Clinical Pearls for NEET-PG:** * **The Nephritic Pentad:** Hematuria, Oliguria, Azotemia, Hypertension, and Edema (usually periorbital) [2]. * **Most common cause:** Post-Streptococcal Glomerulonephritis (PSGN) is the classic prototype, occurring 1–3 weeks after a skin or throat infection [2]. * **Diagnostic Clue:** Low C3 complement levels are typically seen in PSGN, Systemic Lupus Erythematosus (SLE), and Membranoproliferative GN.

Q: What is the most important sign in hemodynamically significant renal artery stenosis?

Presence of collateral vessels. **Explanation:** The hallmark of **hemodynamically significant renal artery stenosis (RAS)** is the functional impact of the narrowing on renal perfusion. **1. Why "Presence of collateral vessels" is correct:** The development of collateral circulation (typically from the ureteral, adrenal, or capsular arteries) is the most definitive sign of a hemodynamically significant stenosis. Collaterals only form when the pressure gradient across the stenosis is high enough to recruit alternative pathways to maintain renal blood flow. This indicates that the stenosis is severe enough (usually >70-80% occlusion) to trigger a compensatory anatomical response. **2. Analysis of Incorrect Options:** * **Elevated renin level (Ipsilateral):** While a renin ratio of ≥ 1.5:1 between the affected and unaffected side suggests renovascular hypertension, it is a functional marker of ischemia rather than a definitive anatomical sign of significant stenosis. It can be influenced by medications (ACE inhibitors/Beta-blockers) [1]. * **Transstenotic pressure gradient:** A peak systolic pressure gradient of **≥ 20 mm Hg** (not 40 mm Hg) or a mean gradient of **> 10 mm Hg** is generally considered hemodynamically significant. Option C provides an incorrect threshold. * **Decrease in renal size:** While a difference in kidney size (>1.5 cm) is a common finding in chronic RAS, it is a non-specific sign of renal atrophy and can occur in various parenchymal diseases [1]. **Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Digital Subtraction Angiography (DSA). * **Initial Screening Tool:** Duplex Doppler Ultrasound (look for "Tardus Parvus" pulse). * **Classic Presentation:** Resistant hypertension, flash pulmonary edema, or AKI after starting an ACE inhibitor [1]. * **Most common cause:** Atherosclerosis (elderly males); Fibromuscular Dysplasia (young females).

Q: For a patient with chronic renal failure (CRF), which of the following would be a specific indication to start dialysis?

Pericardial friction rub. ### Explanation In the management of Chronic Renal Failure (CRF), the decision to initiate dialysis is based on clinical manifestations of uremia rather than isolated laboratory values [1]. **Why Option D is Correct:** A **pericardial friction rub** is a diagnostic sign of **uremic pericarditis**, which is an absolute and urgent indication for dialysis. Uremic toxins cause inflammation of the pericardial sac; if left untreated, this can progress to pericardial effusion or life-threatening cardiac tamponade. Unlike other complications, uremic pericarditis does not respond to conservative management and requires immediate renal replacement therapy (RRT). **Why the Other Options are Incorrect:** * **Option A (BUN >90 mg/dl):** There is no absolute numerical threshold for BUN to start dialysis. While high levels (often >100 mg/dl) correlate with uremia, the patient’s clinical status (e.g., encephalopathy, vomiting) is more important than the number itself [1]. * **Option B (Urine output <10 ml/h):** Oliguria alone is not a specific indication for dialysis in CRF. Many patients with end-stage renal disease (ESRD) remain oliguric for months while being managed conservatively until other systemic complications arise. * **Option C (Hematocrit <30%):** Anemia is a common feature of CRF due to erythropoietin deficiency [1]. It is managed with Erythropoiesis-Stimulating Agents (ESAs) and iron supplementation, not dialysis. **Clinical Pearls for NEET-PG:** To remember the urgent indications for dialysis, use the mnemonic **AEIOU**: * **A** – Refractory Metabolic **A**cidosis (pH 6.5 mEq/L or ECG changes) * **I** – **I**ntoxications (e.g., Salicylates, Lithium, Methanol, Ethylene glycol) * **O** – Refractory Fluid **O**verload (Pulmonary edema) * **U** – **U**remic complications (**Pericarditis**, Encephalopathy, Asterixis, or bleeding diathesis) [1]

Question 1

In which stage of Chronic Kidney Disease is a decrease in Glomerular Filtration Rate (GFR) typically apparent?

Accepted Answer

Stage II

Answer

Stage I

Answer

Stage III

Answer

Stage IV

Question 2

Which of the following are treatments for hyperkalemia?

Accepted Answer

All of the above

Answer

Intravenous dextrose infusion

Answer

Parenteral sodium bicarbonate

Answer

Albuterol

Question 3

Which of the following are causes of anemia in Chronic Kidney Disease (CKD)?

Accepted Answer

All the above

Answer

Erythropoietin production deficiency

Answer

Folic acid deficiency

Answer

Decreased erythrocyte survival

Question 4

A patient in the oliguric phase of renal failure is expected to have a 24-hour urine output less than which of the following values?

Accepted Answer

400ml

Answer

200ml

Answer

800ml

Answer

1000ml

Question 5

Urinary eosinophilia is a feature of?

Accepted Answer

Atheroembolic kidney disease

Answer

Renal vein thrombosis

Answer

Gaucher disease

Answer

Myeloma Kidney

Question 6

A 21-year-old female presents with a history of brown-colored urine that occurred approximately two months prior, lasting for about three days, following a cold. Currently, urinalysis shows blood with red cells and red cell casts. Further laboratory tests, including CBC, serum electrolytes, BUN, creatinine, glucose, ANAs, and serum complement levels (C3 and C4), are all within normal limits. Immunofluorescence examination of a renal biopsy reveals large, irregular deposits of IgA/C3 in the mesangium, with no linear staining pattern. What is the most likely diagnosis for this patient?

Accepted Answer

Berger's disease

Answer

Focal segmental glomerulosclerosis

Answer

Goodpasture's disease

Answer

Lipoid nephrosis

Question 7

Which of the following is NOT a feature of acute glomerulonephritis?

Accepted Answer

Polyuria

Answer

Hematuria

Answer

Red cell cast

Answer

Oliguria

Question 8

What is the most important sign in hemodynamically significant renal artery stenosis?

Accepted Answer

Presence of collateral vessels

Answer

Elevated renin level in ipsilateral renal vein

≥ 1.5 : 1

Answer

Transstenotic pressure gradient

≥ 40 mm Hg

Answer

Decrease in renal size

Question 9

For a patient with chronic renal failure (CRF), which of the following would be a specific indication to start dialysis?

Accepted Answer

Pericardial friction rub

Answer

Blood urea nitrogen (BUN) rises to >90 mg/dl

Answer

Urine output falls to <10 ml/h

Answer

Hematocrit falls to <30%

Question 10

Urine analysis of a patient suffering from heatstroke reveals which of the following?

Accepted Answer

Red cell casts

Answer

Isomorphic red cells

Answer

Hemosiderin

Answer

Hyaline cast

Nephrology — MCQs

Nephrology — MCQs

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