Nephrology Practice Questions

Q: What is the frequency of renal involvement in Henoch-Schonlein Purpura (HSP)?

40-60%. **Explanation:** Henoch-Schönlein Purpura (HSP), now commonly referred to as **IgA Vasculitis**, is the most common systemic vasculitis in children. It is characterized by the classic tetrad of palpable purpura, arthritis/arthralgia, abdominal pain, and renal involvement. **1. Why 40-60% is correct:** Renal involvement (HSP Nephritis) occurs in approximately **40-60%** of affected children. While the cutaneous and gastrointestinal symptoms often appear first, renal manifestations—ranging from microscopic hematuria and proteinuria to nephritic or nephrotic syndrome—typically develop within 4 to 6 weeks of the initial presentation. It is the most serious complication of HSP, as it determines the long-term prognosis of the patient. **2. Analysis of Incorrect Options:** * **A (20-40%):** This underestimates the prevalence. While some mild cases may go undetected, prospective screening shows a higher incidence. * **B (>80%):** This is too high. While skin involvement is present in 100% of cases and GI symptoms in ~75%, renal involvement does not occur in the vast majority. * **D (10%):** This is significantly lower than the established clinical data for pediatric populations. **3. NEET-PG High-Yield Pearls:** * **Pathology:** Renal biopsy shows mesangial IgA deposition, identical to **IgA Nephropathy (Berger’s Disease)**; hence, HSP is often considered the systemic version of IgA Nephropathy. * **Prognosis:** Most children recover fully, but **1-5%** may progress to End-Stage Renal Disease (ESRD). * **Monitoring:** All patients with HSP require serial urinalysis and blood pressure monitoring for at least **6 months** post-diagnosis to catch late-onset nephritis. * **Treatment:** While steroids help with GI pain, they do not prevent the development of renal disease. Severe nephritis may require immunosuppressants (e.g., Cyclophosphamide).

Q: The final stage of congenital nephrotic syndrome occurs due to gene mutations affecting which of the following proteins?

Nephrin. **Explanation:** The correct answer is **Nephrin (Option C)**. Congenital Nephrotic Syndrome of the Finnish type (CNF) is an autosomal recessive disorder caused by a mutation in the **NPHS1 gene**, which encodes the protein **Nephrin**. **Why Nephrin is correct:** Nephrin is a transmembrane protein located in the **slit diaphragm** between the foot processes of podocytes. It acts as a primary molecular sieve, preventing the leakage of albumin into the urine. In CNF, the absence or dysfunction of Nephrin leads to the complete breakdown of the filtration barrier, resulting in massive proteinuria starting in utero or shortly after birth. **Analysis of Incorrect Options:** * **Option A: Podocin:** Mutations in the **NPHS2 gene** encode Podocin. While this causes Steroid-Resistant Nephrotic Syndrome (SRNS), it typically presents in early childhood (Autosomal Recessive) rather than the classic congenital Finnish type. * **Option B: Alpha-actinin-4:** Mutations in the **ACTN4 gene** lead to an Autosomal Dominant form of Focal Segmental Glomerulosclerosis (FSGS), usually presenting in adolescence or adulthood. * **Option C: CD2-associated protein (CD2AP):** This protein anchors Nephrin to the actin cytoskeleton. Mutations are rare but are associated with sporadic cases of FSGS rather than classic congenital nephrotic syndrome. **NEET-PG High-Yield Pearls:** * **Finnish Type (NPHS1):** Presents with a large placenta (>25% of birth weight) and elevated maternal serum alpha-fetoprotein (MSAFP). * **Treatment:** CNF is resistant to steroids; definitive management requires bilateral nephrectomy followed by dialysis and renal transplantation. * **Denys-Drash Syndrome:** Characterized by early-onset nephrotic syndrome, Wilms tumor, and male pseudohermaphroditism (WT1 gene mutation).

Q: A 20-year-old male presents with features of acute renal failure 5 days after an episode of diarrhea. Blood examination shows thrombocytopenia and Hb 10 gm%. What is the likely cause?

Haemolytic uremic syndrome. ### Explanation The clinical presentation of **Acute Renal Failure (ARF)**, **Thrombocytopenia**, and **Anemia** (Microangiopathic Hemolytic Anemia) following a diarrheal episode is the classic triad of **Hemolytic Uremic Syndrome (HUS)**. **1. Why Option A is correct:** HUS is primarily caused by **Shiga toxin-producing *E. coli* (STEC)**, most commonly serotype **O157:H7**. The toxin causes endothelial injury in the glomerular microvasculature, leading to platelet aggregation (thrombocytopenia) and the formation of microthrombi. As Red Blood Cells (RBCs) pass through these narrowed vessels, they are mechanically shredded, resulting in **schistocytes** (fragmented cells) and hemolytic anemia. The renal involvement manifests as oliguria and azotemia. **2. Why the other options are incorrect:** * **B. Hereditary Spherocytosis:** This is a congenital membrane defect causing extravascular hemolysis in the spleen. It presents with jaundice and splenomegaly, not acute renal failure or thrombocytopenia. * **C. Hemolytic Crises:** While this involves rapid RBC destruction (often seen in G6PD deficiency or Sickle Cell Disease), it does not typically present with the specific triad of thrombocytopenia and prodromal diarrhea leading to ARF. * **D. Chronic Glomerulonephritis:** This presents with a long-term history of hypertension, proteinuria, and shrunken kidneys, rather than an acute onset following a gastrointestinal infection. **Clinical Pearls for NEET-PG:** * **Most common cause of ARF in children:** HUS. * **Peripheral Smear:** Look for **Schistocytes** (helmet cells). * **D+ HUS (Typical):** Associated with diarrhea (STEC). * **D- HUS (Atypical):** Associated with complement dysregulation (Factor H deficiency). * **Management:** Primarily supportive (dialysis, transfusion). **Antibiotics and anti-motility agents are contraindicated** as they may increase toxin release.

Q: What condition carries a high risk of renal dysplasia?

Posterior urethral valve. **Explanation:** **Posterior Urethral Valve (PUV)** is the most common cause of lower urinary tract obstruction (LUTO) in male infants. The high risk of **renal dysplasia** in PUV is explained by the **"Pop-off Mechanism"** and the timing of the insult. During fetal development, the obstruction causes high intravesical pressure, which is transmitted back to the developing metanephros. This increased pressure disrupts normal nephrogenesis, leading to irreversible cystic renal dysplasia (Potter sequence in severe cases). The degree of dysplasia is often inversely proportional to the presence of "pop-off" valves (like a VUR or urinoma) which can sometimes decompress the system. **Analysis of Incorrect Options:** * **Bladder Exstrophy:** While this is a severe malformation of the genitourinary tract, the primary issue is a failure of the abdominal wall to close. It is not typically associated with high-pressure obstructive uropathy in utero, so renal dysplasia is rare at birth. * **Anorectal Malformation (ARM):** ARMs are frequently associated with renal anomalies (as part of the VACTERL association), most commonly renal agenesis or ectopia, but they do not physiologically cause renal dysplasia via obstruction. * **Neonatal Sepsis:** This is an acquired systemic infection. While it can lead to Acute Kidney Injury (AKI) due to hypoperfusion or nephrotoxicity, it does not cause structural renal dysplasia. **Clinical Pearls for NEET-PG:** * **Classic Triad of PUV:** Distended bladder, weak urinary stream, and a palpable renal mass (hydronephrosis). * **Diagnosis:** The gold standard investigation is **Voiding Cystourethrogram (VCUG)**, which shows a dilated posterior urethra and a "spinning top" bladder. * **Antenatal Ultrasound:** Look for the **"Keyhole sign"** (dilated bladder and posterior urethra). * **Prognosis:** Serum creatinine at the end of the first year of life is the best predictor of long-term renal function.

Q: Which of the following statements about nephrotic syndrome in a child are true or false? 1. Minimal change nephrotic syndrome accounts for 80-85% of cases. 2. Serum albumin level is typically below 2.5 g/dL. 3. Cyclosporine and azathioprine are the mainstay of therapy. 4. Pretreatment biopsy is performed in all cases.

1 and 2 are true, 3 and 4 are false. **Explanation:** Nephrotic syndrome in children is characterized by the triad of massive proteinuria (>40 mg/m²/hr), hypoalbuminemia, and edema. 1. **Statement 1 is True:** Minimal Change Disease (MCD) is the most common histological subtype in children, accounting for approximately **80–85%** of cases. It typically presents between ages 1 and 7 and is highly steroid-responsive. 2. **Statement 2 is True:** Hypoalbuminemia is a hallmark of the condition. Diagnostic criteria generally define it as a serum albumin level **<2.5 g/dL**. This leads to decreased oncotic pressure and subsequent edema. 3. **Statement 3 is False:** The mainstay of therapy is **Corticosteroids (Prednisolone)**. Cyclosporine is a second-line agent used for steroid-resistant or dependent cases. Azathioprine has limited efficacy in MCD and is rarely used. 4. **Statement 4 is False:** Pretreatment biopsy is **not** indicated in most children. Since the majority have MCD, a trial of steroids is initiated empirically. Biopsy is reserved for "atypical" presentations (age 12 years, gross hematuria, hypertension, or low complement levels) and steroid resistance. **High-Yield Clinical Pearls for NEET-PG:** * **First-line treatment:** Prednisolone at 2 mg/kg/day (max 60 mg) for 6 weeks, followed by 1.5 mg/kg alternate days for 6 weeks. * **Most common complication:** Infections (specifically **Spontaneous Bacterial Peritonitis** caused by *S. pneumoniae*). * **Hyperlipidemia:** Common due to increased hepatic synthesis of lipoproteins triggered by low oncotic pressure. * **Relapse definition:** Urine albumin 3+ or 4+ for 3 consecutive days.

Q: Potter's Facies is seen with which of the following conditions?

Bilateral renal agenesis. **Explanation:** **Potter’s Facies** is a characteristic physical appearance of a newborn resulting from **oligohydramnios** (low amniotic fluid). The correct answer is **Bilateral renal agenesis**, as fetal urine is the primary contributor to amniotic fluid volume in the second and third trimesters. **The Underlying Concept: Potter Sequence** When kidneys fail to develop (bilateral renal agenesis) or are obstructed, the lack of fetal urine leads to severe oligohydramnios. This results in: 1. **Mechanical Compression:** The uterine walls press directly against the fetus, causing the "Potter’s Facies" (flattened nose, recessed chin, prominent epicanthal folds, and low-set, "pressed" ears). 2. **Pulmonary Hypoplasia:** Amniotic fluid is essential for lung development; its absence is the most common cause of death in these neonates. 3. **Limb Deformities:** Clubbed feet and joint contractures due to lack of space for movement. **Analysis of Incorrect Options:** * **Xanthogranulomatous pyelonephritis:** A chronic inflammatory process (often due to *Proteus* infection) resulting in a non-functioning kidney, but it is usually unilateral and occurs later in life. * **Hepatic fibrosis:** While associated with Autosomal Recessive Polycystic Kidney Disease (ARPKD)—which *can* cause Potter sequence—isolated hepatic fibrosis does not cause oligohydramnios. * **Kasabach-Merritt Syndrome:** A rare condition involving giant hemangiomas and consumptive coagulopathy (thrombocytopenia); it has no association with renal development. **High-Yield Pearls for NEET-PG:** * **Potter Type I:** ARPKD (Infantile type). * **Potter Type II:** Renal Agenesis (Multicystic dysplastic kidney). * **Potter Type III:** ADPKD (Adult type presenting in infancy). * **Potter Type IV:** Obstructive uropathy (e.g., Posterior Urethral Valves). * **Most common cause of death:** Pulmonary hypoplasia, not renal failure.

Q: Which of the following findings is considered proteinuria in a case of nephrotic syndrome?

All the above. Nephrotic syndrome in children is clinically defined by a triad of **massive proteinuria**, hypoalbuminemia ( 40 mg/m²/hr**. This is calculated via a timed (usually 24-hour) urine collection. * **Option B (Spot Protein:Creatinine Ratio):** Since 24-hour collections are difficult in children, a random "spot" urine sample is often used. A **Protein:Creatinine ratio (uPCR) >2 mg/mg** (or >200 mg/mmol) correlates accurately with nephrotic-range proteinuria. * **Option C (Urine Dipstick):** This is the most common screening tool. A semi-quantitative reading of **3+ or 4+** (which corresponds to >300 mg/dL or 1000 mg/dL respectively) on a fresh morning sample is diagnostic of heavy proteinuria. Since all three criteria are valid methods to define nephrotic-range proteinuria, **Option D** is the correct answer. ### **High-Yield Clinical Pearls for NEET-PG:** * **Definition of Remission:** Urine dipstick 0 or Trace for 3 consecutive days. * **Definition of Relapse:** Urine dipstick ≥2+ for 3 consecutive days. * **Most Common Cause:** Minimal Change Disease (MCD) is the most common cause of nephrotic syndrome in children (80-85%). * **First-line Treatment:** Prednisolone (2 mg/kg/day) for 6 weeks, followed by 1.5 mg/kg on alternate days for 6 weeks. * **Key Complication:** Spontaneous Bacterial Peritonitis (most common organism: *Streptococcus pneumoniae*).

Q: What is the characteristic finding in the peripheral smear of a patient with hemolytic uremic syndrome?

Burr cells with fragmented red blood cells. **Explanation:** Hemolytic Uremic Syndrome (HUS) is characterized by the classic triad of **Microangiopathic Hemolytic Anemia (MAHA)**, thrombocytopenia, and acute kidney injury. The primary pathology involves endothelial injury, leading to the formation of microthrombi in small vessels (predominantly glomerular capillaries). As Red Blood Cells (RBCs) attempt to pass through these partially occluded vessels, they are mechanically shredded by fibrin strands. This process results in the hallmark finding on a peripheral smear: **Fragmented RBCs (Schistocytes/Helmet cells)** and **Burr cells (Echinocytes)**. **Analysis of Options:** * **Option D (Correct):** The combination of fragmented RBCs (schistocytes) and Burr cells is the diagnostic morphological feature of MAHA seen in HUS. * **Option A:** While Burr cells are seen in uremia (renal failure), they are not the *only* finding. In HUS, the mechanical fragmentation (schistocytes) is equally critical for diagnosis. * **Option B:** Anisopoikilocytosis refers to variation in size and shape; while present, it is a non-specific finding seen in many anemias (like Iron Deficiency) and is not diagnostic of HUS. * **Option C:** A leukemoid reaction (high WBC count) may occur in severe infections but is not a characteristic feature of the RBC morphology required to diagnose HUS. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Shiga toxin-producing *E. coli* (STEC), specifically serotype **O157:H7**. * **Triad:** Microangiopathic Hemolytic Anemia + Thrombocytopenia + Acute Renal Failure. * **Lab findings:** Increased LDH, decreased haptoglobin, and a **Negative Direct Coombs Test** (distinguishes it from autoimmune hemolysis). * **Management:** Primarily supportive; **Antibiotics and Platelet transfusions are generally avoided** as they may worsen the toxin release and microthrombi formation.

Question 1

What is the frequency of renal involvement in Henoch-Schonlein Purpura (HSP)?

Accepted Answer

40-60%

Answer

20-40%

Answer

>80%

Answer

10%

Question 2

The final stage of congenital nephrotic syndrome occurs due to gene mutations affecting which of the following proteins?

Accepted Answer

Nephrin

Answer

Podocin

Answer

Alpha-actinin

Answer

CD2 activated protein

Question 3

A 20-year-old male presents with features of acute renal failure 5 days after an episode of diarrhea. Blood examination shows thrombocytopenia and Hb 10 gm%. What is the likely cause?

Accepted Answer

Haemolytic uremic syndrome

Answer

Hereditary spherocytosis

Answer

Haemolytic crises

Answer

Chronic glomerulonephritis

Question 4

An 8-year-old boy presents with headaches, dizziness, and malaise approximately 2 weeks after a severe sore throat. His mother describes puffiness of his face and darkening of his urine. She also notes that her son is passing less urine and that he is becoming increasingly short of breath. On physical examination, there is anasarca, hypertension (190/130 mm Hg), and tachycardia. The urine is scanty and brownish red. Urinalysis shows 3+ proteinuria. Microscopic examination of the urine discloses numerous RBCs, as well as occasional granular and red cell casts. A renal biopsy is stained by direct immunofluorescence microscopy for complement C3. Which of the following is the most likely cause of acute postinfectious glomerulonephritis in the patient?

Accepted Answer

Group A beta-hemolytic streptococci

Answer

Escherichia coli

Answer

Epstein-Barr virus

Answer

Klebsiella sp.

Question 5

What condition carries a high risk of renal dysplasia?

Accepted Answer

Posterior urethral valve

Answer

Bladder exstrophy

Answer

Anorectal malformation

Answer

Neonatal sepsis

Question 6

Which of the following statements about nephrotic syndrome in a child are true or false?
1. Minimal change nephrotic syndrome accounts for 80-85% of cases.
2. Serum albumin level is typically below 2.5 g/dL.
3. Cyclosporine and azathioprine are the mainstay of therapy.
4. Pretreatment biopsy is performed in all cases.

Accepted Answer

1 and 2 are true, 3 and 4 are false

Answer

1 and 4 are true, 2 and 3 are false

Answer

3 and 4 are true, 1 and 2 are false

Answer

2 and 3 are false, 1 and 4 are true

Question 7

Potter's Facies is seen with which of the following conditions?

Accepted Answer

Bilateral renal agenesis

Answer

Xanthogranulomatous pyelonephritis

Answer

Hepatic fibrosis

Answer

Kasabach-Merritt Syndrome

Question 8

Which of the following findings is considered proteinuria in a case of nephrotic syndrome?

Accepted Answer

All the above

Answer

Urine albumin >40 mg/m2/hr

Answer

Spot urine protein : creatinine ratio >2

Answer

Urine dipstick 3+ or 4+

Question 9

What is the characteristic finding in the peripheral smear of a patient with hemolytic uremic syndrome?

Accepted Answer

Burr cells with fragmented red blood cells

Answer

Burr cell

Answer

Anisopoikilocytosis

Answer

Leukemoid reaction

Question 10

What is the most common cause of rapidly progressive glomerulonephritis in children?

Accepted Answer

Pauci-immune glomerulonephritis

Answer

Goodpasture syndrome

Answer

Membranous glomerulonephritis

Answer

IgA nephropathy

Nephrology — MCQs

Nephrology — MCQs

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