Nephrology Practice Questions

Q: Chyluria is associated with the passage of urine which is:

White. ### Explanation **Correct Answer: A. White** **Medical Concept:** Chyluria is the presence of **chyle** (a mixture of lymph and emulsified fats/chylomicrons) in the urine. This occurs due to an abnormal communication between the intestinal lymphatics and the urinary tract (lymphourinary fistula). Because chyle contains a high concentration of triglycerides and fat globules, it gives the urine a characteristic **milky-white, turbid appearance**. [1] **Analysis of Options:** * **A. White (Correct):** The high lipid content (chylomicrons) scatters light, resulting in a milky appearance. This is the hallmark of chyluria. * **B. Dark yellow:** Typically seen in concentrated urine (dehydration) or conjugated hyperbilirubinemia. * **C. Straw coloured:** This is the appearance of normal, healthy urine due to the pigment urochrome. [1] * **D. Brown:** Often referred to as "tea-colored" or "cola-colored" urine, this is associated with myoglobinuria, hemoglobinuria, or acute glomerulonephritis. **Clinical Pearls for NEET-PG:** * **Etiology:** The most common cause worldwide is **Wuchereria bancrofti** (Filariasis), which causes lymphatic obstruction. Non-parasitic causes include trauma, tumors, or congenital malformations. * **Diagnosis:** 1. **Ether Test:** Adding ether to the urine dissolves the fat, making the urine clear (confirmatory bedside test). 2. **Biochemical:** Presence of triglycerides in urine. * **Clinical Feature:** Patients may complain of "milky urine" that may clot upon standing (due to fibrinogen in lymph). * **Management:** Conservative management includes a **High Protein, Low Fat diet** (specifically supplemented with **Medium Chain Triglycerides/MCTs**, as they are absorbed directly into the portal vein, bypassing the lymphatics).

Q: All are features of HIV-associated nephropathy, EXCEPT:

Edema. HIV-Associated Nephropathy (HIVAN) is a classic manifestation of HIV infection, typically presenting as a **collapsing variant of Focal Segmental Glomerulosclerosis (FSGS)**. It is most commonly seen in patients of African descent with the APOL1 risk allele. [1] **Why "Edema" is the correct answer:** Despite having massive, nephrotic-range proteinuria, patients with HIVAN characteristically **do not present with edema or hypertension**. The exact mechanism is not fully elucidated, but it is attributed to the rapid progression of the disease and the profound tubulointerstitial damage that may lead to a "salt-wasting" state, preventing the fluid retention typically seen in other nephrotic syndromes. **Analysis of Incorrect Options:** * **A. Nephrotic range proteinuria:** This is a hallmark of HIVAN. Patients often present with heavy proteinuria (frequently >3.5g/day) due to severe podocyte injury. [1] * **B. Large kidney:** Unlike most causes of chronic kidney disease where kidneys shrink, HIVAN is characterized by **normal to large-sized, echogenic kidneys** on ultrasound. This is due to marked interstitial edema and tubular dilation (microcystic transformation). * **C. Hypoalbuminemia:** Due to the massive loss of protein in the urine (nephrotic range), serum albumin levels drop significantly. **NEET-PG High-Yield Pearls:** * **Pathology:** Collapsing FSGS with microcystic tubular dilation. * **Electron Microscopy:** Presence of **Tubuloreticular inclusions (TRIs)** in endothelial cells (induced by high Interferon-alpha levels). * **Clinical Course:** Rapid progression to End-Stage Renal Disease (ESRD) if untreated. * **Treatment:** Highly Active Antiretroviral Therapy (HAART) is the mainstay of treatment and can stabilize renal function. ACE inhibitors/ARBs are used for proteinuria.

Q: A 28-year-old male sustained a severe crush injury in an accident. Which of the following complications is he most likely to develop?

Acute Renal Failure. The clinical scenario describes a classic case of **Rhabdomyolysis** following a crush injury. When muscle tissue is severely damaged, it releases large amounts of **myoglobin** into the bloodstream [1]. **Why Acute Renal Failure (ARF) is the correct answer:** Myoglobin causes Acute Kidney Injury (AKI/ARF) through three primary mechanisms [2]: 1. **Intratubular obstruction:** Myoglobin precipitates with Tamm-Horsfall protein in the distal tubules, forming casts. 2. **Direct cytotoxicity:** The heme fraction of myoglobin is toxic to proximal tubular cells. 3. **Renal Vasoconstriction:** Myoglobin scavenges Nitric Oxide, leading to intrarenal ischemia. **Analysis of Incorrect Options:** * **B. Hypophosphatemia:** Incorrect. Muscle cell lysis releases intracellular phosphate, leading to **Hyperphosphatemia**, not hypophosphatemia. * **C. Hypercalcemia:** Incorrect. In the acute phase, calcium deposits in damaged muscle (dystrophic calcification), leading to **Hypocalcemia**. Hypercalcemia may only occur later during the recovery phase as calcium is mobilized back into the blood. * **D. Acute Myocardial Infarction:** While hyperkalemia from muscle breakdown can cause arrhythmias, a direct MI is not a standard complication of crush injury in a young patient. **NEET-PG High-Yield Pearls:** * **Diagnosis:** The most sensitive marker is an elevated **Serum Creatine Kinase (CK)**, typically >5 times the upper limit. * **Urinalysis:** A "dipstick positive for blood" but "negative for RBCs on microscopy" is pathognomonic for myoglobinuria. * **Management:** Aggressive fluid resuscitation with Normal Saline is the gold standard to maintain high urine output and prevent pigment cast formation [3]. * **Electrolyte Triad:** Hyperkalemia, Hyperphosphatemia, and Hypocalcemia.

Q: Hematuria with dysmorphic RBCs is a feature of which one of the following?

Hereditary nephritis. **Explanation:** The presence of **dysmorphic Red Blood Cells (RBCs)** in urine is a hallmark of **glomerular bleeding**. When RBCs pass through the damaged glomerular basement membrane (GBM) and travel through the varying osmotic gradients of the renal tubules, they undergo mechanical and chemical stress, leading to distorted shapes (e.g., acanthocytes or "Mickey Mouse" cells). * **Hereditary Nephritis (Alport Syndrome):** This is a glomerular disease caused by mutations in Type IV collagen. Since the pathology lies within the glomerulus, RBCs must cross the GBM to enter the filtrate, resulting in dysmorphic RBCs and RBC casts. * **Incorrect Options (A, B, and D):** These represent **extra-glomerular (lower urinary tract)** sources of bleeding. In these cases, RBCs enter the urine downstream from the nephron, bypassing the osmotic stress of the tubules. Consequently, the RBCs remain **isomorphic** (uniform in size and shape). * **Acute Cystitis & Prostatitis:** Inflammation of the bladder and prostate, respectively. * **Cyclophosphamide Toxicity:** Causes **Hemorrhagic Cystitis** due to the metabolite acrolein irritating the bladder lining. **NEET-PG High-Yield Pearls:** 1. **Acanthocytes:** A specific type of dysmorphic RBC with vesicle-like protrusions; if they comprise >5% of urinary RBCs, it is highly predictive of glomerular disease. 2. **RBC Casts:** Always indicate a renal/glomerular origin of hematuria. 3. **Terminal Hematuria:** Suggests a bladder neck or prostatic source. 4. **Initial Hematuria:** Suggests a urethral source. 5. **Total Hematuria:** Suggests a source at or above the level of the bladder (including kidneys).

Q: Which of the following criteria is included in the definition of Acute Kidney Injury?

50% increase in baseline serum creatinine in a week. The definition of **Acute Kidney Injury (AKI)** is standardized globally by the **KDIGO (Kidney Disease: Improving Global Outcomes)** criteria. AKI is defined by a rapid decline in renal function, characterized by specific changes in serum creatinine (SCr) or urine output [1]. ### Why Option D is Correct According to KDIGO, AKI is diagnosed if any of the following occur: 1. **Increase in SCr by ≥0.3 mg/dL** within 48 hours. 2. **Increase in SCr to ≥1.5 times baseline** (a 50% increase) within the last 7 days [1]. 3. **Urine output 20:1 suggests **Prerenal Azotemia** (due to increased urea reabsorption), but it is a diagnostic clue for the *cause* of AKI, not part of the formal definition. * **Option C:** "Urine output <1000 mL/day" is not a criterion. **Oliguria** is defined as <400 mL/day, and **Anuria** as <100 mL/day. AKI criteria use weight-based hourly output (<0.5 mL/kg/h). ### High-Yield NEET-PG Pearls * **Staging:** KDIGO Stage 3 (Failure) is defined by a 3-fold increase in SCr, SCr ≥4.0 mg/dL, or the initiation of Renal Replacement Therapy (RRT). * **Earliest Marker:** Urine output usually drops before SCr rises. * **New Biomarkers:** For exams, remember **NGAL** (Neutrophil Gelatinase-Associated Lipocalin) and **KIM-1** (Kidney Injury Molecule-1) are early markers of tubular damage, often rising before creatinine.

Question 1

Chinese herb nephropathy is caused by which of the following?

Accepted Answer

Aristolochic acid

Answer

Mushroom

Answer

Lead poisoning

Answer

Tenofovir

Question 2

Chyluria is associated with the passage of urine which is:

Accepted Answer

White

Answer

Dark yellow

Answer

Straw coloured

Answer

Brown

Question 3

Uremia is not associated with hypertension in which of the following situations?

Accepted Answer

Renal amyloidosis

Answer

Renal polyarteritis nodosa

Answer

Narrowing of the renal artery

Answer

Hyperplastic aeriolar nephrosclerosis

Question 4

All are features of HIV-associated nephropathy, EXCEPT:

Accepted Answer

Edema

Answer

Nephrotic range proteinuria

Answer

Large kidney

Answer

Hypoalbuminemia

Question 5

A 28-year-old male sustained a severe crush injury in an accident. Which of the following complications is he most likely to develop?

Accepted Answer

Acute Renal Failure

Answer

Hypophosphatemia

Answer

Hypercalcemia

Answer

Acute Myocardial Infarction

Question 6

Which of the following is not a cause of chloride-responsive metabolic alkalosis?

Accepted Answer

Congenital adrenal hyperplasia

Answer

Vomiting

Answer

Cystic fibrosis

Answer

Post hypercapnia syndrome

Question 7

Hematuria with dysmorphic RBCs is a feature of which one of the following?

Accepted Answer

Hereditary nephritis

Answer

Acute cystitis

Answer

Prostatitis

Answer

Cyclophosphamide toxicity

Question 8

Serum C3 is persistently low in which of the following conditions?

Accepted Answer

Lupus nephritis

Answer

Post-streptococcal glomerulonephritis

Answer

Membranoproliferative glomerulonephritis

Answer

Glomerulonephritis related to bacterial endocarditis

Question 9

A 19-year-old man presents with hemoptysis and decreased urine output. Physical examination reveals normal lung and heart sounds, with no skin rash, palpable lymph nodes, or abdominal abnormalities. Chest X-ray shows bilateral lower lobe infiltrates, and his creatinine is elevated. Urinalysis is positive for red blood cells and protein. A renal biopsy reveals autoantibodies to basement membranes. Which of the following is the most likely diagnosis?

Accepted Answer

Goodpasture syndrome

Answer

Thyroiditis

Answer

Myasthenia gravis

Answer

Thrombocytopenia

Question 10

Which of the following criteria is included in the definition of Acute Kidney Injury?

Accepted Answer

50% increase in baseline serum creatinine in a week

Answer

Increase of serum creatinine by 1 mg/dL in 24 hours

Answer

BUN/Creatinine ratio above 20

Answer

Urine output less than 1000 mL in a day

Nephrology — MCQs

Nephrology — MCQs

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