Nephrology Practice Questions

Q: Hyperchloremic metabolic acidosis is seen in all EXCEPT?

Gitelman syndrome. The core concept tested here is the differentiation between **Normal Anion Gap Metabolic Acidosis (NAGMA)** and **Metabolic Alkalosis**. **Why Gitelman Syndrome is the correct answer:** Gitelman syndrome is a salt-wasting tubulopathy caused by a defect in the thiazide-sensitive NaCl cotransporter in the distal convoluted tubule. It presents with **Metabolic Alkalosis** (not acidosis), hypokalemia, and hypomagnesemia [1]. Because it causes alkalosis, it cannot be the cause of hyperchloremic metabolic acidosis. **Analysis of incorrect options (Causes of NAGMA):** * **Renal Tubular Acidosis (RTA) Type 1:** RTAs are classic causes of NAGMA [2]. In Type 1 (Distal RTA), there is a failure to secrete H+ ions. To maintain electrical neutrality, the kidney retains Chloride, leading to hyperchloremia. * **Diarrhea:** This is the most common gastrointestinal cause of NAGMA. Loss of bicarbonate-rich intestinal fluids leads to a relative increase in serum Chloride to balance the loss of HCO3-. * **Uremia:** While advanced chronic kidney disease (CKD) typically causes a High Anion Gap Metabolic Acidosis (HAGMA) due to phosphate/sulfate retention, **early-stage renal failure (uremia)** often presents as a hyperchloremic NAGMA before the anion gap widens. **NEET-PG High-Yield Pearls:** 1. **NAGMA Formula:** Remember the mnemonic **USED CARP** (Ureterosigmoidostomy, Small bowel fistula, Extra-chloride, Diarrhea, Carbonic anhydrase inhibitors, RTA, Pancreatic fistula). 2. **Gitelman vs. Bartter:** Gitelman presents in older children/adults with **hypocalciuria**, whereas Bartter presents in infancy with **hypercalciuria**. Both cause metabolic alkalosis [1]. 3. **Anion Gap:** Always calculate the Anion Gap ($Na - [Cl + HCO3]$). If it is normal (8–12 mEq/L) in the presence of acidosis, it is Hyperchloremic Metabolic Acidosis [2].

Q: All are features of Rapidly progressive glomerulonephritis (RPGN) except?

Rapid recovery. **Explanation:** Rapidly Progressive Glomerulonephritis (RPGN) is a clinical syndrome characterized by a rapid and progressive loss of renal function, typically leading to end-stage renal disease (ESRD) within weeks to months if left untreated [3]. **Why "Rapid recovery" is the correct answer:** RPGN is defined by its aggressive nature. Without aggressive immunosuppressive therapy (such as pulse steroids, cyclophosphamide, or plasmapheresis), it does **not** recover rapidly; instead, it leads to irreversible renal failure [3]. Recovery is often incomplete even with treatment, making "Rapid recovery" the false statement. **Analysis of incorrect options:** * **Crescent formation:** This is the hallmark pathological feature of RPGN [1], [2]. Crescents form due to the proliferation of parietal epithelial cells and the infiltration of monocytes into Bowman’s space following glomerular capillary wall rupture [2]. * **Hypertension:** As a form of nephritic syndrome, RPGN involves fluid retention and activation of the renin-angiotensin system, leading to hypertension and edema [2]. * **Non-selective proteinuria:** Damage to the glomerular filtration barrier allows proteins of various molecular weights to leak into the urine [2]. While usually not in the nephrotic range, the proteinuria is non-selective [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Classification:** RPGN is divided into three types [1]: * **Type I:** Anti-GBM disease (e.g., Goodpasture syndrome) – Linear IgG deposits [1], [3]. * **Type II:** Immune-complex mediated (e.g., PSGN, SLE) – Granular deposits [1], [3]. * **Type III:** Pauci-immune (e.g., Wegener’s/GPA, Microscopic polyangiitis) – ANCA associated [3]. * **Histology:** Diagnosis requires >50% of glomeruli to show crescent formation on light microscopy [1]. * **Urinalysis:** Characterized by "active sediment" (RBC casts and dysmorphic RBCs).

Q: Nephrocalcinosis is seen in which of the following conditions?

Medullary sponge kidney. **Explanation:** Nephrocalcinosis refers to the generalized deposition of calcium salts (calcium oxalate or calcium phosphate) within the renal parenchyma [3]. It is typically classified into medullary (most common) and cortical types [3]. **1. Why Medullary Sponge Kidney (MSK) is Correct:** MSK is a congenital disorder characterized by cystic dilatation of the collecting ducts [1]. This leads to urinary stasis and localized hypercalciuria within the dilated ducts, creating an ideal environment for the formation of calcium phosphate or calcium oxalate stones [1]. Consequently, MSK is one of the most common causes of **medullary nephrocalcinosis**. **2. Why the Other Options are Incorrect:** * **Hypoparathyroidism:** This condition is characterized by *low* serum calcium levels [4]. Nephrocalcinosis is associated with **Hyperparathyroidism** (due to hypercalcemia and hypercalciuria) [3]. * **Diabetes Mellitus:** While DM is a leading cause of chronic kidney disease and papillary necrosis, it does not typically cause the parenchymal calcium deposition seen in nephrocalcinosis. **3. High-Yield Clinical Pearls for NEET-PG:** * **Medullary Nephrocalcinosis (Common Causes):** Remember the mnemonic **"R-A-M"**: **R**enal Tubular Acidosis (Type 1/Distal), **A**ntacids (Milk-alkali syndrome), and **M**edullary Sponge Kidney [3]. Hyperparathyroidism and Sarcoidosis are also major causes [2], [3]. * **Cortical Nephrocalcinosis (Rare):** Classically seen in **Acute Tubular Necrosis (ATN)**, Chronic Glomerulonephritis, and **Ethylene Glycol poisoning**. It may occur in areas of cortical necrosis [3]. * **Radiology:** On X-ray or CT, MSK presents with a characteristic "bouquet of flowers" or "paintbrush" appearance due to contrast filling the dilated ducts [1].

Q: All of the following may be associated with massive proteinuria EXCEPT?

Polyarteritis nodosa. Massive proteinuria (nephrotic-range proteinuria, typically >3.5 g/day) occurs due to significant damage to the glomerular filtration barrier (podocytes or basement membrane) [2]. **Why Polyarteritis Nodosa (PAN) is the correct answer:** PAN is a systemic necrotizing vasculitis that primarily affects **medium-sized arteries**. In the kidneys, it involves the renal arteries and their branches (interlobar and arcuate arteries), leading to microaneurysms, ischemia, and infarction. Crucially, PAN **spares the glomeruli** (it is a non-glomerular disease). Therefore, it typically presents with hypertension and hematuria, but **not** massive proteinuria [3]. **Analysis of Incorrect Options:** * **Amyloidosis:** This is a classic cause of nephrotic syndrome. Deposition of amyloid fibrils in the glomerular basement membrane disrupts the filtration barrier, leading to some of the highest levels of proteinuria seen in clinical practice [4]. * **Renal Vein Thrombosis (RVT):** RVT is both a cause and a consequence of nephrotic syndrome. While it is most commonly associated with Membranous Nephropathy, the resulting venous congestion can exacerbate glomerular damage and proteinuria. * **Polycystic Kidneys (ADPKD):** While mild-to-moderate proteinuria is more common, massive proteinuria can occur in advanced stages due to secondary focal segmental glomerulosclerosis (FSGS) caused by hyperfiltration in the remaining nephrons [1]. **NEET-PG High-Yield Pearls:** * **PAN Rule of Thumb:** PAN is "Glomerulonephritis-negative." If a vasculitis involves the glomerulus (causing RPGN or massive proteinuria), think of Small Vessel Vasculitis (e.g., GPA, MPA) instead [3]. * **PAN & Hepatitis B:** Approximately 10-30% of PAN cases are associated with Hepatitis B surface antigenemia. * **Diagnosis:** The gold standard for PAN is a biopsy or visceral angiography showing "string of pearls" microaneurysms.

Q: Which of the following is used for staging of Chronic Kidney Disease (CKD)?

Estimated Glomerular Filtration Rate (e-GFR) and albuminuria. **Explanation:** The staging of Chronic Kidney Disease (CKD) is based on the **KDIGO (Kidney Disease: Improving Global Outcomes)** classification system, which utilizes two primary parameters: **e-GFR (G-stage)** and **Albuminuria (A-stage)** [1]. This is often referred to as the "CGA" classification (Cause, GFR, and Albuminuria). 1. **Why Option D is correct:** CKD is defined as abnormalities of kidney structure or function present for >3 months [1]. While e-GFR measures the filtration capacity (Stages G1–G5), albuminuria (measured via Urine Albumin-to-Creatinine Ratio - UACR) is a sensitive marker of kidney damage and a potent predictor of cardiovascular risk and progression to End-Stage Renal Disease (ESRD) [1]. Even if e-GFR is normal (>90 ml/min), a patient can be diagnosed with CKD if persistent albuminuria is present. 2. **Why other options are incorrect:** * **Option A:** Serum creatinine is used to *calculate* e-GFR (via formulas like CKD-EPI), but it is not a staging criterion on its own due to variations based on muscle mass and age [1]. * **Option B:** Serum albumin reflects nutritional status or systemic inflammation; it is not used for CKD staging. * **Option C:** Urine output is a criterion for **AKIs (Acute Kidney Injury)** via the RIFLE, AKIN, or KDIGO criteria, but it is not used for staging chronic disease. **High-Yield Clinical Pearls for NEET-PG:** * **CKD Definition:** e-GFR 3 months** [1]. * **Formula of Choice:** The **CKD-EPI formula** is currently preferred over MDRD for estimating GFR. * **Albuminuria Categories:** A1 ( 300 mg/g - "macroalbuminuria") [1]. * **Most common cause of CKD:** Diabetes Mellitus (followed by Hypertension) [1].

Q: Systemic eosinophilia with renal failure is found in all of the following except:

Chronic interstitial nephritis. ### Explanation The presence of **systemic eosinophilia** in the context of renal failure is a significant diagnostic clue pointing toward hypersensitivity, embolic, or vasculitic processes. **Why Chronic Interstitial Nephritis (CIN) is the correct answer:** Chronic Interstitial Nephritis is characterized by progressive interstitial fibrosis and tubular atrophy [2]. Unlike the acute form, the inflammatory infiltrate in CIN is predominantly mononuclear (lymphocytes and macrophages) rather than eosinophilic. Because it is a chronic, scarring process rather than an active hypersensitivity reaction, it is **not** associated with systemic eosinophilia or eosinophiluria. **Analysis of Incorrect Options:** * **Drug-induced Acute Interstitial Nephritis (AIN):** This is a classic Type IV hypersensitivity reaction. Systemic eosinophilia is seen in approximately 30–50% of cases, often accompanied by a skin rash and fever [3]. * **Atherosclerotic Renal Failure (Atheroembolic Disease):** Following vascular procedures, cholesterol crystals can dislodge and cause distal ischemia [1]. This triggers a systemic inflammatory response, and **eosinophilia** is a hallmark laboratory finding in about 60–80% of these patients [1]. * **Polyarteritis Nodosa (PAN):** As a systemic necrotizing vasculitis, PAN (especially when associated with certain triggers or overlapping with eosinophilic granulomatosis with polyangiitis) can present with significant peripheral eosinophilia and multi-organ failure, including the kidneys [3]. **NEET-PG High-Yield Pearls:** 1. **Hansel’s Stain:** The preferred stain to detect eosinophils in urine (more sensitive than Wright’s stain). 2. **Triad of AIN:** Fever, rash, and arthralgia (though all three are present in <10% of patients). 3. **Atheroembolic Clue:** Look for "blue toe syndrome" or livedo reticularis following a cardiac catheterization in a patient with rising creatinine and eosinophilia [1].

Q: A 25-year-old man presents with renal failure. His uncle died of renal failure 3 years ago. On slit lamp examination, keratoconus is present. What is the most likely diagnosis?

Alport syndrome. **Explanation:** The clinical triad of **hereditary renal failure**, a positive **family history**, and specific **ocular abnormalities** (like keratoconus) is classic for **Alport Syndrome** [1]. **1. Why Alport Syndrome is correct:** Alport syndrome is caused by mutations in the genes encoding the **alpha chains of Type IV collagen** (COL4A3, COL4A4, COL4A5) [1]. Since Type IV collagen is a structural component of basement membranes, its defect affects: * **Kidneys:** Leads to progressive glomerulonephritis and renal failure. * **Eyes:** Causes **Anterior Lenticonus** (pathognomonic), **Keratoconus**, and maculopathy. * **Ears:** Results in Sensorineural Hearing Loss (SNHL). The mention of the uncle's death suggests an X-linked dominant inheritance pattern (the most common form), though autosomal forms exist. **2. Why other options are incorrect:** * **ADPCKD:** While it causes renal failure and has a strong family history, it typically presents in the 4th-5th decade and is associated with extra-renal manifestations like hepatic cysts and berry aneurysms, not keratoconus [2]. * **ARPCKD:** Usually presents in infancy or childhood with bilateral flank masses and pulmonary hypoplasia; it is associated with congenital hepatic fibrosis, not ocular defects. * **Denys-Drash Syndrome:** Characterized by the triad of Wilms tumor, pseudohermaphroditism, and early-onset nephropathy. It does not feature a family history of renal failure or keratoconus. **Clinical Pearls for NEET-PG:** * **Pathognomonic Eye Sign:** Anterior Lenticonus (conical protrusion of the lens). * **Electron Microscopy (EM):** Shows a characteristic **"Basket-weave appearance"** due to irregular thinning and thickening of the Glomerular Basement Membrane (GBM) [1]. * **Inheritance:** 80% are X-linked Dominant (mutations in *COL4A5*). * **Rule of thumb:** If a young male has hematuria, hearing loss, and eye signs—think Alport Syndrome.

Q: What is the best initial test for determining the stage of renal insufficiency?

Serum creatinine. **Explanation:** **1. Why Serum Creatinine is the Correct Answer:** Serum creatinine is considered the **best initial test** because it is simple, inexpensive, and widely available [1]. In clinical practice, the staging of Chronic Kidney Disease (CKD) is primarily based on the **Estimated Glomerular Filtration Rate (eGFR)**, which is calculated using formulas (like MDRD or CKD-EPI) that rely predominantly on the **serum creatinine** value [1]. It serves as the fundamental baseline biomarker for assessing renal function in an initial workup. **2. Analysis of Incorrect Options:** * **Creatinine Clearance (CrCl):** While more accurate than serum creatinine alone, it requires a cumbersome **24-hour urine collection**, making it impractical as an "initial" test [2]. It is usually reserved for specific scenarios like pregnancy, extremes of body size, or prior to dosing highly toxic drugs. * **Glomerular Filtration Rate (GFR):** This is the "Gold Standard" for determining the *actual* stage of renal insufficiency [2]. However, true GFR measurement requires the infusion of exogenous markers like **Inulin** (the physiological gold standard) or radioisotopes (Iothalamate) [1]. These are complex and expensive, hence not the "initial" test. * **Serum Urea:** This is an unreliable marker for staging because levels are significantly influenced by non-renal factors such as high-protein diet, GI bleed, dehydration, and steroid use. **3. Clinical Pearls for NEET-PG:** * **Gold Standard for GFR:** Inulin clearance [2]. * **Most accurate formula for eGFR:** CKD-EPI (preferred over MDRD) [1]. * **Creatinine Lag:** Serum creatinine may not rise until **50% of nephron function** is lost, making it a late marker in acute settings but the standard for staging chronic insufficiency. * **Cockcroft-Gault Formula:** Used for drug dosing; it incorporates Age, Weight, and Serum Creatinine.

Question 1

Fractional excretion of sodium < 1 is seen in which of the following conditions?

Accepted Answer

Pre-renal azotemia

Answer

Acute tubular necrosis

Answer

Acute ureteral obstruction

Answer

Interstitial nephritis

Question 2

Hyperchloremic metabolic acidosis is seen in all EXCEPT?

Accepted Answer

Gitelman syndrome

Answer

Renal tubular acidosis type 1

Answer

Diarrhea

Answer

Uremia

Question 3

All are features of Rapidly progressive glomerulonephritis (RPGN) except?

Accepted Answer

Rapid recovery

Answer

Crescent formation

Answer

Hypertension

Answer

Non-selective proteinuria

Question 4

Nephrocalcinosis is seen in which of the following conditions?

Accepted Answer

Medullary sponge kidney

Answer

Hypoparathyroidism

Answer

Diabetes Mellitus

Answer

All of the above

Question 5

All of the following may be associated with massive proteinuria EXCEPT?

Accepted Answer

Polyarteritis nodosa

Answer

Amyloidosis

Answer

Renal vein thrombosis

Answer

Polycystic kidneys

Question 6

Which of the following is used for staging of Chronic Kidney Disease (CKD)?

Accepted Answer

Estimated Glomerular Filtration Rate (e-GFR) and albuminuria

Answer

Estimated Glomerular Filtration Rate (e-GFR) and serum creatinine

Answer

Estimated Glomerular Filtration Rate (e-GFR) and serum albumin

Answer

Estimated Glomerular Filtration Rate (e-GFR) and urine output

Question 7

Systemic eosinophilia with renal failure is found in all of the following except:

Accepted Answer

Chronic interstitial nephritis

Answer

Drug-induced interstitial nephritis

Answer

Atherosclerotic renal failure

Answer

Polyarteritis nodosa

Question 8

A 25-year-old man presents with renal failure. His uncle died of renal failure 3 years ago. On slit lamp examination, keratoconus is present. What is the most likely diagnosis?

Accepted Answer

Alport syndrome

Answer

Autosomal Dominant Polycystic Kidney Disease (ADPCKD)

Answer

Autosomal Recessive Polycystic Kidney Disease (ARPCKD)

Answer

Denys-Drash syndrome

Question 9

T.T.K.G >8 is seen in all except?

Accepted Answer

Cushing syndrome

Answer

Diabetes mellitus

Answer

Acute glomerulonephritis

Answer

Adrenocortical insufficiency

Question 10

What is the best initial test for determining the stage of renal insufficiency?

Accepted Answer

Serum creatinine

Answer

Creatinine clearance

Answer

Glomerular filtration rate

Answer

Serum urea

Nephrology — MCQs

Nephrology — MCQs

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