Nephrology Practice Questions

Q: Proximal tubular dysfunction is seen in all of the following disorders EXCEPT?

Fabry disease. The question tests the ability to distinguish between various lysosomal storage disorders and their specific renal manifestations. Proximal tubular dysfunction, often manifesting as **Fanconi Syndrome** (characterized by glucosuria, phosphaturia, aminoaciduria, and bicarbonate loss), is a hallmark of certain metabolic diseases but is notably absent in others [1]. **1. Why Fabry Disease is the Correct Answer:** Fabry disease is an X-linked recessive deficiency of **$\alpha$-galactosidase A**, leading to the accumulation of globotriaosylceramide (Gb3). While it causes significant renal pathology, the primary site of damage is the **glomerulus** (podocytes) and the **distal nephron/collecting ducts**. It presents with proteinuria and progressive renal failure, but it does **not** typically cause proximal tubular dysfunction or Fanconi syndrome. **2. Analysis of Incorrect Options:** * **Cystinosis:** This is the **most common cause** of inherited Fanconi syndrome in children. Cystine crystals accumulate within the lysosomes of proximal tubular cells, leading to severe dysfunction. * **Lowe Syndrome (Oculocerebrorenal syndrome):** An X-linked disorder affecting the *OCRL1* gene. It presents with a classic triad of congenital cataracts, intellectual disability, and **proximal renal tubular acidosis**. * **Pompe Disease (GSD Type II):** While primarily a neuromuscular disorder (acid maltase deficiency), glycogen accumulation can occur in the proximal tubules, leading to tubular dysfunction in some clinical presentations. **Clinical Pearls for NEET-PG:** * **Fanconi Syndrome Mnemonic:** "**L**ow **C**ystine **W**ilson **G**lycogen" (**L**owe, **C**ystinosis, **W**ilson disease, **G**alactosemia/Glycogen storage diseases) [2]. * **Fabry Disease Key Finding:** Look for "Maltese cross" appearance of lipid droplets in urine and angiokeratomas on physical exam. * **Cystinosis Key Finding:** Corneal cystine crystals on slit-lamp exam.

Q: A 22-year-old male presents with fever, hematuria, and hypertension. Intravenous pyelography (IVP) shows a "spider leg" deformity. What is the most likely diagnosis?

Autosomal dominant polycystic kidney disease (ADPKD). ### Explanation **Correct Option: A. Autosomal dominant polycystic kidney disease (ADPKD)** The "spider leg" appearance on Intravenous Pyelography (IVP) is a classic radiological sign of ADPKD. This occurs because multiple large, fluid-filled cysts in the renal parenchyma compress and stretch the renal calyces and pelvis, making them appear elongated, thin, and spindly—resembling the legs of a spider. Clinically, ADPKD often presents in young adults (20–40 years) [1] with a triad of hypertension, hematuria, and palpable abdominal masses (flank pain). **Analysis of Incorrect Options:** * **B. ARPKD:** Typically presents in infancy or childhood with bilateral flank masses and renal failure. On IVP, it shows a characteristic **"sunray" or "paintbrush" appearance** due to dilated collecting ducts, rather than calyceal stretching. * **C. Medullary sponge kidney:** Characterized by cystic dilatation of the collecting ducts. The classic IVP finding is a **"bouquet of flowers" or "paintbrush" appearance** [2] due to the accumulation of contrast in the dilated ducts. * **D. Hydronephrosis:** Results in the dilatation of the renal pelvis and calyces. On IVP, this appears as **"clubbing" of the calyces**, not the thin, elongated deformity seen in ADPKD. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Most common cause is a mutation in the **PKD1 gene** (Chromosome 16), followed by PKD2 (Chromosome 4) [1]. * **Extra-renal manifestations:** The most common is **Liver cysts**. The most serious is **Berry aneurysms** (leading to Subarachnoid Hemorrhage). Others include mitral valve prolapse and diverticulosis. * **Diagnosis:** Ultrasound is the initial investigation of choice (Revised Ravine’s criteria). * **Treatment:** Tolvaptan (Vasopressin V2 receptor antagonist) is used to slow disease progression.

Q: How is glomerular proteinuria differentiated from non-glomerular proteinuria?

Proteinuria > 3.0 - 3.5 g/day. The differentiation between glomerular and non-glomerular (tubular or overflow) proteinuria is based on the **quantity** and **composition** of the proteins excreted. **1. Why Option A is Correct:** The glomerular filtration barrier (basement membrane and podocytes) normally restricts large proteins like albumin [2]. When this barrier is significantly damaged (e.g., Nephrotic Syndrome), massive amounts of protein leak into the urine [1]. **Proteinuria > 3.0 - 3.5 g/day** is almost exclusively a hallmark of **glomerular disease** [1]. In contrast, tubular or overflow proteinuria rarely exceeds 2 g/day because the filtered load of small proteins is limited. **2. Analysis of Incorrect Options:** * **Option B:** In glomerular proteinuria, **Albumin > Globulin** (selective or non-selective). Globulins predominate in "Overflow Proteinuria" (e.g., Multiple Myeloma) [1]. * **Option C:** The **Albumin to $eta_2$-microglobulin ratio** is a classic differentiator. In glomerular disease, the ratio is high (**>1000:1**) because albumin is the primary protein. A ratio of **<10:1** suggests tubular disease, where low-molecular-weight proteins like $eta_2$-microglobulin are not reabsorbed. * **Option D:** **Tamm-Horsfall protein** (Uromodulin) is a physiological protein secreted by the thick ascending limb of Henle. It is the matrix for all urinary casts but does not help differentiate the etiology of pathological proteinuria. **Clinical Pearls for NEET-PG:** * **Gold Standard for quantification:** 24-hour urine protein collection (though Spot Protein-Creatinine Ratio is preferred in practice) [1]. * **Dipstick Sensitivity:** Primarily detects **Albumin** [1]. It may miss Bence-Jones proteins (globulins) seen in Multiple Myeloma (Sulfosalicylic acid test is used instead) [1]. * **Microalbuminuria:** 30–300 mg/day; the earliest sign of Diabetic Nephropathy [1].

Q: Chronic renal failure with inappropriately high haemoglobin levels may be seen with which of the following conditions?

Polycystic renal disease. **Explanation:** In most cases of Chronic Kidney Disease (CKD), patients develop **normocytic normochromic anemia** due to the deficiency of Erythropoietin (EPO), which is primarily produced by the peritubular interstitial cells of the kidney [4]. **Why Polycystic Kidney Disease (PKD) is the correct answer:** In **Autosomal Dominant Polycystic Kidney Disease (ADPKD)**, the renal cysts are lined with epithelial cells that can become hypoxic due to the expansion of the cysts compressing surrounding vasculature. This localized intrarenal hypoxia stimulates the cyst walls and the remaining compressed parenchyma [1] to continue producing **Erythropoietin**. Consequently, patients with PKD often maintain higher hemoglobin levels than expected for their degree of renal failure, and in some cases, they may even develop secondary polycythemia. **Why the other options are incorrect:** * **A & B (Hypertensive and Ischaemic Nephropathy):** These conditions involve progressive loss of the renal parenchyma and interstitial fibrosis [3], leading to a predictable decline in EPO production and significant anemia. * **C (Diabetic Nephropathy):** This is actually associated with **disproportionately severe anemia** [2]. Damage to the autonomic nerves (denervation of the kidney) and tubulointerstitial fibrosis often lead to an earlier and more profound EPO deficiency compared to other causes of CKD. **High-Yield Clinical Pearls for NEET-PG:** * **"Relative Polycythemia" in CKD:** Apart from ADPKD, other renal conditions associated with high EPO/Hgb include **Renal Cell Carcinoma (RCC)**, Hydronephrosis, and Post-renal transplant erythrocytosis. * **Anemia in CKD:** Usually starts when GFR falls below **30-45 mL/min**. * **Target Hgb:** In CKD patients on EPO therapy, the target Hgb is typically **10–11.5 g/dL**; exceeding 13 g/dL increases the risk of cardiovascular events and stroke.

Q: Which of the following are considered bad prognostic factors in Lupus Nephritis?

All of the above. Lupus Nephritis (LN) is one of the most severe complications of Systemic Lupus Erythematosus (SLE). [1] Prognosis is determined by both clinical markers and histological findings (ISN/RPS classification). **Why "All of the Above" is Correct:** The progression of renal damage in SLE is driven by immune complex deposition and subsequent inflammatory cascades. The following are established indicators of poor renal outcomes: * **Anti-dsDNA Antibodies:** High titers are strongly associated with active lupus nephritis (especially Class III and IV). They correlate with disease flares and indicate a higher risk of progression to End-Stage Renal Disease (ESRD). * **Hypocomplementemia (Low C3, C4):** Low complement levels signify active classical pathway consumption due to immune complex formation. Persistent hypocomplementemia despite treatment suggests ongoing disease activity and a higher likelihood of chronic scarring. * **Persistent Proteinuria (>3 gm/day):** Nephrotic-range proteinuria that fails to resolve with induction therapy is a major predictor of poor long-term prognosis. It indicates significant glomerular basement membrane damage and increases the risk of interstitial fibrosis. **Clinical Pearls for NEET-PG:** 1. **Most Common Cause of Death in SLE:** Renal failure (early) and Cardiovascular disease (late). 2. **Gold Standard for Diagnosis:** Renal Biopsy. It is essential to differentiate between proliferative (Class III/IV) and membranous (Class V) types, as management differs. [1] 3. **Most Common & Severe Type:** Class IV (Diffuse Proliferative Lupus Nephritis). 4. **Other Bad Prognostic Factors:** Elevated Serum Creatinine at presentation, African-American ethnicity, and high "Chronicity Index" on biopsy. 5. **Treatment Goal:** Achieving a "Complete Renal Response" (proteinuria <0.5g/day and normal Cr) within 6–12 months is the best predictor of long-term kidney survival.

Q: Which of the following is not a common manifestation of nephrotic syndrome?

Hematuria. **Explanation:** The hallmark of **Nephrotic Syndrome** is the disruption of the glomerular filtration barrier (specifically the podocytes), leading to massive protein loss [1]. To diagnose Nephrotic Syndrome, a triad of clinical findings must be present: **Heavy proteinuria (>3.5 g/day), Hypoalbuminemia (<3 g/dL), and Generalized Edema (Anasarca).** **Why Hematuria is the correct answer:** Hematuria is the classic feature of **Nephritic Syndrome**, which involves inflammatory damage to the glomerular capillaries (e.g., PSGN, IgA Nephropathy) [1]. While "microscopic" hematuria can occasionally occur in certain nephrotic conditions (like Membranous Nephropathy), it is **not** a defining or common manifestation. Nephrotic syndrome is primarily a "non-inflammatory" protein-losing state. **Analysis of Incorrect Options:** * **Hypoalbuminemia:** Direct result of massive urinary protein loss (proteinuria) [1]. As the liver cannot synthesize albumin fast enough to compensate for the loss, serum levels drop. * **Anasarca:** Low serum albumin decreases **plasma oncotic pressure**, leading to fluid extravasation into the interstitium, causing generalized edema (anasarca) [1]. * **Hyperlipidemia:** In response to low oncotic pressure, the liver increases the synthesis of lipoproteins (LDL, VLDL) [1]. Additionally, there is decreased catabolism of lipids due to the loss of lipoprotein lipase in the urine. **High-Yield Clinical Pearls for NEET-PG:** * **Hypercoagulability:** Nephrotic patients are at high risk for venous thromboembolism (especially **Renal Vein Thrombosis**) due to the urinary loss of **Antithrombin III**, Protein C, and S [1]. * **Infection Risk:** Increased susceptibility to encapsulated organisms (e.g., *S. pneumoniae*) due to the loss of **Immunoglobulins** and Complement factors in urine [1]. * **Maltese Cross Appearance:** Seen under polarized microscopy in the urine sediment due to lipiduria (fatty casts).

Q: Chronic laxative abuse can result in the formation of which type of renal stone?

Ammonium urate. **Explanation:** The correct answer is **Ammonium urate**. **Pathophysiology:** Chronic laxative abuse leads to chronic diarrhea, resulting in significant loss of water, bicarbonate, and potassium from the gastrointestinal tract. This triggers a specific metabolic environment conducive to ammonium urate stone formation: 1. **Dehydration:** Leads to low urine volume and concentrated urine. 2. **Metabolic Acidosis:** Loss of bicarbonate causes the kidneys to increase **ammoniagenesis** (production of $NH_4^+$) to buffer the acid. 3. **Hypokalemia:** Intracellular potassium depletion further stimulates renal ammonia production. 4. **Hyperuricosuria:** The resulting acidic, concentrated urine with high ammonium concentrations promotes the precipitation of ammonium acid urate. **Analysis of Incorrect Options:** * **A. Xanthine:** These are rare stones typically associated with hereditary xanthine oxidase deficiency or the use of Allopurinol. * **B. Cysteine:** These occur due to an autosomal recessive defect in the transport of dibasic amino acids (COLA: Cysteine, Ornithine, Lysine, Arginine) in the proximal tubule. * **D. Struvite (Triple Phosphate):** These are "infection stones" (Magnesium Ammonium Phosphate) associated with urease-producing bacteria like *Proteus* or *Klebsiella*, which make the urine alkaline [1]. **Clinical Pearls for NEET-PG:** * **Ammonium urate stones** are radiolucent (like pure uric acid stones) but may appear faintly radiopaque if they co-precipitate with calcium [2]. * They are also commonly seen in patients with **inflammatory bowel disease (IBD)** due to similar chronic malabsorption/diarrhea mechanisms. * **Key Triad for Laxative Abuse:** Hypokalemia, metabolic alkalosis (if vomiting) or acidosis (if diarrhea), and ammonium urate stones.

Question 1

Proximal tubular dysfunction is seen in all of the following disorders EXCEPT?

Accepted Answer

Fabry disease

Answer

Pompe disease

Answer

Lowe syndrome

Answer

Cystinosis

Question 2

All are true for nephrotic syndrome except?

Accepted Answer

Hypertension

Answer

Edema

Answer

Massive proteinuria

Answer

Hyperlipidemia

Question 3

A 30-year-old female patient is undergoing hemodialysis with an internal arteriovenous fistula in place. What measures should be taken to prevent complications associated with this device?

Accepted Answer

Avoid taking blood pressures in the arm with the fistula.

Answer

Insert intravenous lines above the fistula.

Answer

Palpate pulses above the fistula.

Answer

Report any bruit or thrill over the fistula to the physician.

Question 4

A 22-year-old male presents with fever, hematuria, and hypertension. Intravenous pyelography (IVP) shows a "spider leg" deformity. What is the most likely diagnosis?

Accepted Answer

Autosomal dominant polycystic kidney disease (ADPKD)

Answer

Autosomal recessive polycystic kidney disease (ARPKD)

Answer

Medullary sponge kidney

Answer

Hydronephrosis

Question 5

How is glomerular proteinuria differentiated from non-glomerular proteinuria?

Accepted Answer

Proteinuria > 3.0 - 3.5 g/day

Answer

Globulin > albumin

Answer

Albumin to B2 microglobulin ratio 100:1

Answer

Tamm-Horsfall protein

Question 6

Chronic renal failure with inappropriately high haemoglobin levels may be seen with which of the following conditions?

Accepted Answer

Polycystic renal disease

Answer

Hypertensive nephropathy

Answer

Ischaemic nephropathy

Answer

Diabetic nephropathy

Question 7

Which of the following are considered bad prognostic factors in Lupus Nephritis?

Accepted Answer

All of the above

Answer

Anti-ds DNA antibodies

Answer

Hypocomplementemia

Answer

Persistent proteinuria (>3 gm/day)

Question 8

Which of the following is not a common manifestation of nephrotic syndrome?

Accepted Answer

Hematuria

Answer

Hyperlipidemia

Answer

Anasarca

Answer

Hypoalbuminemia

Question 9

Chronic laxative abuse can result in the formation of which type of renal stone?

Accepted Answer

Ammonium urate

Answer

Xanthine

Answer

Cysteine

Answer

Struvite

Question 10

A patient has Insulin-Dependent Diabetes Mellitus diagnosed at age 15 years. What is the most reliable indicator for diabetic nephropathy?

Accepted Answer

Urinary protein greater than 550 mg per day for 3 consecutive samples

Answer

Urine albumin less than 50 mg per day in 3 consecutive samples

Answer

Development of diabetic retinopathy

Answer

Hematuria

Nephrology — MCQs

Nephrology — MCQs

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