Nephrology — MCQs

Q: What is the most common cause of urinary tract infection in children?

Escherichia coli. **Explanation:** **Escherichia coli (Option A)** is the most common cause of urinary tract infection (UTI) in children, accounting for approximately **80–90% of all cases**. The primary mechanism is the ascending route, where fecal flora colonize the perineum and enter the bladder. *E. coli* possesses specific virulence factors, such as **P-fimbriae (pyelonephritis-associated pili)**, which allow the bacteria to adhere to the uroepithelial cells and resist being washed away by urine flow. **Why other options are incorrect:** * **Klebsiella species (Option B):** While it is the second most common Gram-negative cause, it typically occurs in children with recurrent UTIs, those who have received prior antibiotics, or those with structural abnormalities. * **Pseudomonas aeruginosa (Option C):** This is an opportunistic pathogen. It is rarely a cause in healthy children and is usually associated with hospital-acquired infections, urinary tract instrumentation (catheterization), or chronic structural malformations. * **Candida (Option D):** Fungal UTIs are uncommon in immunocompetent children. They are typically seen in neonates in the NICU, children on prolonged broad-spectrum antibiotics, or those with indwelling catheters. **High-Yield Clinical Pearls for NEET-PG:** * **Most common route of infection:** Ascending route (except in neonates, where hematogenous spread is more common). * **Most common viral cause:** Adenovirus (typically causes acute hemorrhagic cystitis). * **Gold Standard Diagnosis:** Urine culture obtained via suprapubic aspiration (any growth is significant) or transurethral catheterization (>50,000 CFU/mL). * **Proteus mirabilis:** Often associated with UTIs in uncircumcised males and is linked to the formation of struvite (staghorn) calculi due to its urease-producing nature.

Q: A 10-year-old boy presents with hypertension. There is no other significant history. What is the most likely cause of his hypertension?

Polycystic kidney disease. **Explanation:** In the pediatric population, hypertension is most commonly **secondary** to an underlying condition, with renal causes accounting for over 80% of cases. **Why Polycystic Kidney Disease (PKD) is the correct answer:** While "Renal Parenchymal Disease" is a broad category, **Autosomal Dominant Polycystic Kidney Disease (ADPKD)** is a specific and frequent cause of asymptomatic hypertension in older children (around age 10). Hypertension in PKD often precedes a significant decline in glomerular filtration rate (GFR) due to the activation of the Renin-Angiotensin-Aldosterone System (RAAS) caused by cyst expansion and local renal ischemia. In the context of a child presenting with *isolated* hypertension and no other history (like hematuria or edema), PKD is a high-yield diagnosis. **Analysis of Incorrect Options:** * **Chronic Glomerulonephritis:** Usually presents with a history of hematuria, proteinuria, or previous episodes of acute nephritic syndrome. * **Reflux Nephropathy:** Typically associated with a history of recurrent Urinary Tract Infections (UTIs) or voiding dysfunction, which is absent in this clinical vignette. * **Renal Parenchymal Disease:** This is a general umbrella term that includes glomerulonephritis, pyelonephritis, and PKD. In competitive exams like NEET-PG, when a specific disease entity (PKD) is provided alongside a general category, the specific diagnosis is preferred if it fits the clinical profile. **NEET-PG High-Yield Pearls:** * **Most common cause of HTN in children:** Renal Parenchymal Disease (overall). * **Most common cause of HTN in newborns:** Renal Artery Thrombosis (often due to umbilical artery catheterization). * **Gold Standard for diagnosis:** 24-hour Ambulatory Blood Pressure Monitoring (ABPM). * **First-line investigation:** Renal Ultrasound (to look for scars, cysts, or size discrepancies).

Q: A patient with congenital nephrotic syndrome requires which of the following procedures?

Renal biopsy. **Explanation:** **Congenital Nephrotic Syndrome (CNS)** is defined as the onset of nephrotic-range proteinuria, edema, and hypoalbuminemia within the first three months of life. **Why Renal Biopsy is the Correct Answer:** In CNS, a renal biopsy is a critical diagnostic step to differentiate between various underlying etiologies. While the most common cause is the **Finnish type (NPHS1 mutation)**, a biopsy helps rule out other structural or syndromic causes like Diffuse Mesangial Sclerosis (DMS) or secondary causes like congenital syphilis or CMV. Histopathology in the Finnish type typically shows characteristic microcystic dilatation of the proximal tubules. **Analysis of Incorrect Options:** * **Live Attenuated Vaccines:** These are generally **contraindicated** in patients with nephrotic syndrome who are on immunosuppressive therapy or are severely edematous/malnourished due to the risk of disseminated infection. * **High-dose Steroids:** Unlike Minimal Change Disease (MCD) in older children, CNS is **steroid-resistant**. The condition is caused by genetic mutations in podocyte proteins (e.g., Nephrin, Podocin), making steroid therapy ineffective and potentially toxic. * **Low-protein Diet:** Patients with CNS lose massive amounts of albumin in the urine. A low-protein diet would worsen the malnutrition and growth failure. Instead, these infants require a **high-protein, high-calorie diet** to compensate for urinary losses. **High-Yield Clinical Pearls for NEET-PG:** * **Finnish Type (NPHS1):** Most common cause; inherited as autosomal recessive; mutation in the **Nephrin** gene (chromosome 19q13). * **Antenatal Diagnosis:** Elevated **Alpha-fetoprotein (AFP)** levels in amniotic fluid or maternal serum. * **Management:** Definitive treatment is **bilateral nephrectomy** (to stop protein loss) followed by peritoneal dialysis and eventual **renal transplantation**.

Q: An 8-year-old child has had abdominal pain and dark urine for 10 days. Physical examination shows blotchy purple skin lesions on the trunk and extremities. Urinalysis shows hematuria and proteinuria. Serologic test results are negative for myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) and proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA). A skin biopsy specimen shows necrotizing vasculitis of small dermal vessels. A renal biopsy specimen shows immune complex deposition in glomeruli, with some IgA-rich immune complexes. Which of the following is the most likely diagnosis?

Henoch-Schonlein purpura. **Explanation:** The clinical presentation of **abdominal pain, dark urine (hematuria), and palpable purpura** (blotchy purple lesions) in a child is the classic triad of **Henoch-Schönlein Purpura (HSP)**, now commonly referred to as **IgA Vasculitis**. **Why Option B is Correct:** HSP is a small-vessel vasculitis characterized by the deposition of **IgA-dominant immune complexes**. The skin biopsy showing necrotizing vasculitis of small dermal vessels (leukocytoclastic vasculitis) and the renal biopsy showing IgA-rich deposits in the mesangium are pathognomonic. The negative ANCA results help rule out ANCA-associated vasculitides like Granulomatosis with polyangiitis. **Why Other Options are Incorrect:** * **A & D (Giant cell & Takayasu arteritis):** These are **large-vessel vasculitides**. They typically present with absent pulses, bruits, or temporal headaches and do not feature IgA-mediated glomerulonephritis or small-vessel dermal vasculitis. * **C (Polyarteritis nodosa):** This is a **medium-vessel vasculitis**. While it can cause abdominal pain (mesenteric ischemia) and renal involvement, it typically spares the capillaries (glomeruli) and is not associated with IgA deposition. **High-Yield Clinical Pearls for NEET-PG:** * **Most common** systemic vasculitis in children. * **Classic Tetrad:** Palpable purpura (without thrombocytopenia), arthralgia, abdominal pain, and renal disease. * **Triggers:** Often follows an Upper Respiratory Tract Infection (URTI). * **Renal Pathology:** Identical to **IgA Nephropathy (Berger’s disease)**; however, HSP is a systemic multisystem involvement, whereas Berger’s is localized to the kidney. * **Treatment:** Usually supportive; steroids are used for severe gastrointestinal or renal involvement.

Q: After her first urinary tract infection (UTI), a 1-year-old girl has a voiding cystourethrogram with findings shown below. Which of the following is the most appropriate management option?

Low-dose daily antibiotics. ***Low-dose daily antibiotics*** - **Prophylactic antibiotics** are the first-line conservative management for **Grade II-III vesicoureteral reflux (VUR)** in young children to prevent recurrent UTIs and potential **renal scarring**. - This approach allows time for potential **spontaneous resolution** of VUR as the child grows, which commonly occurs in low-to-moderate grade reflux. *Immediate surgical reimplantation of the ureters* - **Ureteral reimplantation** is reserved for **high-grade VUR (Grade IV-V)** or cases with breakthrough infections despite prophylactic antibiotics. - **Grade II-III VUR** often resolves spontaneously with conservative management, making immediate surgery unnecessarily aggressive. *Weekly urinalyses and culture* - **Monitoring alone** without prophylaxis increases the risk of **recurrent UTIs** and potential **renal scarring** in a child with established VUR. - This approach fails to provide **active protection** against ascending infections that VUR predisposes the patient to. *Diet low in protein* - **Protein restriction** is indicated for **chronic kidney disease** with significant **renal impairment**, not for VUR management. - VUR with normal renal function does not require **dietary modifications**, and protein is essential for normal growth in children.

Q: Which of the following is NOT a characteristic of nephrotic syndrome in children?

Low complement levels are typically observed. **Explanation:** The hallmark of **Minimal Change Disease (MCD)**, the most common cause of Nephrotic Syndrome in children, is that it is a **"pauci-immune"** condition. In typical childhood nephrotic syndrome, the complement system is not consumed; therefore, **serum complement levels (C3 and C4) remain normal.** Low complement levels should instead raise suspicion for nephritic conditions like Post-Streptococcal Glomerulonephritis (PSGN), Lupus Nephritis, or Membranoproliferative Glomerulonephritis (MPGN). **Analysis of Options:** * **Option A:** Hypertension is generally **not associated** with pure nephrotic syndrome (MCD). Its presence, along with hematuria, often suggests a "nephritic" component or a different pathology like FSGS. * **Option B:** **Minimal Change Disease** accounts for approximately 80-90% of cases in children under 10 years of age, making it the most common histological subtype in this demographic. * **Option C:** **Massive proteinuria** is the defining feature. In pediatric terms, this is defined as >40 mg/m²/hr or a spot protein:creatinine ratio >2. In adults, the threshold is >3.5 g/24 hours. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Nephrotic Syndrome (Children):** Minimal Change Disease (MCD). * **Most common cause of Nephrotic Syndrome (Adults):** Membranous Nephropathy (globally) or FSGS (increasingly common). * **MCD Morphology:** Light microscopy is normal; Electron microscopy shows **effacement of podocyte foot processes.** * **Treatment:** Corticosteroids (Prednisolone) are the first-line treatment. * **Indications for Renal Biopsy:** Age 12 years, persistent hypertension, gross hematuria, or **low complement levels.**

Q: A 9-year-old boy presents with decreased urine output, cola-colored urine, and swelling of the face and hands for 2 days. He is hypertensive, has a puffy face, and pitting edema of the lower limbs. He had a history of skin lesions 4 weeks prior. A diagnosis of post-streptococcal glomerulonephritis is made. At what point are C3 levels likely to return to normal?

8 weeks. **Explanation:** **1. Why Option C (8 weeks) is correct:** Post-streptococcal glomerulonephritis (PSGN) is an immune-complex-mediated disease (Type III hypersensitivity). The activation of the **alternative complement pathway** leads to the consumption of C3, resulting in low serum C3 levels in >90% of patients during the acute phase. A hallmark of PSGN is that these levels are **transient**. In a typical case, C3 levels begin to rise after the first week and return to the normal range within **6 to 8 weeks**. If C3 remains low beyond 8–12 weeks, alternative diagnoses like Membranoproliferative Glomerulonephritis (MPGN) or Systemic Lupus Erythematosus (SLE) must be considered. **2. Why other options are incorrect:** * **Options A & B (2 and 4 weeks):** While C3 levels start rising early, they usually remain below the normal reference range during the first month of the illness. * **Option D (6 weeks):** Although some patients may normalize by 6 weeks, **8 weeks** is the standard clinical benchmark used in textbooks (like Nelson Pediatrics) and exams to differentiate PSGN from chronic nephritic conditions. **3. High-Yield Clinical Pearls for NEET-PG:** * **Latent Period:** PSGN occurs 1–3 weeks after pharyngitis and 3–6 weeks after pyoderma (skin lesions). * **Sequence of Recovery:** 1. **Diuresis:** First sign of improvement (usually within 1 week). 2. **C3 Normalization:** Within 8 weeks. 3. **Hematuria:** Can persist for 6 months to 1 year. 4. **Proteinuria:** Usually disappears within 6 months. * **Gold Standard Diagnosis:** Renal biopsy (though rarely needed) shows "lumpy-bumpy" appearance on immunofluorescence and "subepithelial humps" on electron microscopy. * **C4 Levels:** Typically remain **normal** in PSGN (unlike SLE where both C3 and C4 are low).

Q: A 3-year-old child presents with 3+ proteinuria, oliguria, and edema. There is no hematuria. What is the most likely diagnosis?

Minimal change glomerulonephritis. **Explanation:** The clinical presentation of **3+ proteinuria, edema, and oliguria** in a 3-year-old child is the classic triad of **Nephrotic Syndrome**. **1. Why Minimal Change Disease (MCD) is correct:** MCD is the most common cause of Nephrotic Syndrome in children (accounting for ~80% of cases). The hallmark of MCD is **"highly selective" proteinuria** (mainly albumin) due to the loss of the glomerular polyanion charge. Crucially, MCD typically presents **without hematuria, hypertension, or azotemia**, making it the most likely diagnosis in this pediatric case. **2. Why other options are incorrect:** * **Membranous Glomerulonephritis:** This is the most common cause of nephrotic syndrome in **adults**, not children. It is often associated with secondary causes like Hepatitis B or SLE. * **Mesangioproliferative Glomerulonephritis:** This often presents with a "nephritic-nephrotic" picture, frequently involving hematuria, which is absent here. * **Rapidly Progressive Glomerulonephritis (RPGN):** This is a **Nephritic Syndrome** characterized by a rapid decline in GFR, crescent formation on biopsy, and prominent hematuria/hypertension. **Clinical Pearls for NEET-PG:** * **Light Microscopy:** Glomeruli appear normal (hence "Minimal Change"). * **Electron Microscopy (Gold Standard):** Shows **effacement (fusion) of podocyte foot processes**. * **Treatment:** Highly steroid-responsive (Prednisolone is the drug of choice). * **Age Factor:** Peak incidence is between **2–6 years**. If a child presents with nephrotic syndrome under 1 year or over 10 years, consider non-MCD causes.

Q: A 10-year-old girl presents with polyuria and polydipsia, along with hypokalemia, hypercalciuria, and metabolic alkalosis. What is the probable diagnosis?

Bartter syndrome. ### Explanation **Bartter Syndrome** is the correct diagnosis because it typically presents in early childhood with the triad of **hypokalemia, metabolic alkalosis, and hypercalciuria**. It is caused by a defect in the thick ascending limb (TAL) of the Loop of Henle (specifically the NKCC2 transporter, ROMK, or ClC-Kb channels). This mimics the effect of **Loop diuretics** (Furosemide), leading to salt wasting, activation of the RAAS system, and increased urinary calcium excretion. #### Why the other options are incorrect: * **Gitelman Syndrome:** Often presents later (adolescence/adulthood). While it also features hypokalemia and metabolic alkalosis, it is characterized by **hypocalciuria** (low urinary calcium), mimicking **Thiazide diuretics**. * **Liddle Syndrome:** This is a "pseudoaldosteronism" caused by overactivity of ENaC channels. While it causes hypokalemia and alkalosis, it presents with **hypertension** and low renin/aldosterone levels. Bartter syndrome patients are typically normotensive. * **Alport’s Syndrome:** This is a collagen IV defect presenting with **hereditary nephritis (hematuria)**, sensorineural deafness, and ocular defects. It does not cause the electrolyte disturbances described. #### High-Yield Clinical Pearls for NEET-PG: * **Bartter vs. Gitelman:** The "Gold Standard" differentiator is urinary calcium. **Bartter = High/Normal Calcium**; **Gitelman = Low Calcium**. * **Mnemonic:** **B**artter is like a **B**oop (Loop) diuretic; **G**itelman is like a **G**iazide (Thiazide) diuretic. * **Antenatal Bartter:** Can present with polyhydramnios and severe salt wasting in the neonatal period. * **Treatment:** NSAIDs (to inhibit prostaglandins) and potassium-sparing diuretics/potassium supplements.

Q: A 2-year-old child presents with a 1-year history of generalized edema. His blood pressure is 107/70 mmHg. Urine examination shows hyaline casts and 3+ proteinuria, with no white blood cells or red blood cells. What is the likely diagnosis?

Selective proteinuria. **Explanation:** The clinical presentation of a 2-year-old with generalized edema and significant proteinuria (3+) without hematuria or hypertension (BP 107/70 mmHg is normal for this age) is classic for **Minimal Change Disease (MCD)**. MCD is the most common cause of Nephrotic Syndrome in children. The hallmark of MCD is **selective proteinuria**, meaning the glomerular basement membrane loses its negative charge (polyanionic charge barrier), allowing small, negatively charged proteins like **albumin** to leak through, while larger proteins (globulins) are retained. **Why other options are incorrect:** * **Uremia:** This refers to the clinical syndrome of advanced renal failure. In this case, the absence of hypertension or mentioned azotemia makes uremia unlikely at presentation. * **Focal Segmental Glomerulosclerosis (FSGS):** While FSGS also causes nephrotic syndrome, it often presents with **non-selective proteinuria**, hypertension, and microscopic hematuria, and is less common than MCD in a 2-year-old. * **Low serum complement level:** Serum C3 and C4 levels are **normal** in MCD and FSGS. Low complement is characteristic of "nephritic" conditions like Post-Streptococcal Glomerulonephritis (PSGN) or Lupus Nephritis. **Clinical Pearls for NEET-PG:** * **MCD Pathogenesis:** Effacement (fusion) of podocyte foot processes seen on Electron Microscopy. * **Light Microscopy:** Appears normal (hence "Minimal Change"). * **Treatment:** Highly steroid-sensitive; Prednisolone is the first-line treatment. * **Selective Proteinuria Index:** A ratio of IgG clearance to Albumin clearance <0.1 indicates highly selective proteinuria.

An 8-year-old child has had abdominal pain and dark urine for 10 days. Physical examination shows blotchy purple skin lesions on the trunk and extremities. Urinalysis shows hematuria and proteinuria. Serologic test results are negative for myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) and proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA). A skin biopsy specimen shows necrotizing vasculitis of small dermal vessels. A renal biopsy specimen shows immune complex deposition in glomeruli, with some IgA-rich immune complexes. Which of the following is the most likely diagnosis?

Q5Medium

After her first urinary tract infection (UTI), a 1-year-old girl has a voiding cystourethrogram with findings shown below. Which of the following is the most appropriate management option?

Q6Medium

Which of the following is NOT a characteristic of nephrotic syndrome in children?

Q7Medium

A 9-year-old boy presents with decreased urine output, cola-colored urine, and swelling of the face and hands for 2 days. He is hypertensive, has a puffy face, and pitting edema of the lower limbs. He had a history of skin lesions 4 weeks prior. A diagnosis of post-streptococcal glomerulonephritis is made. At what point are C3 levels likely to return to normal?

Q8Medium

A 3-year-old child presents with 3+ proteinuria, oliguria, and edema. There is no hematuria. What is the most likely diagnosis?

Q9Medium

A 10-year-old girl presents with polyuria and polydipsia, along with hypokalemia, hypercalciuria, and metabolic alkalosis. What is the probable diagnosis?

Q10Medium

A 2-year-old child presents with a 1-year history of generalized edema. His blood pressure is 107/70 mmHg. Urine examination shows hyaline casts and 3+ proteinuria, with no white blood cells or red blood cells. What is the likely diagnosis?

Nephrology Indian Medical PG Practice Questions and MCQs

Question 1: What is the most common cause of urinary tract infection in children?

A. Escherichia coli (Correct Answer)
B. Klebsiella species
C. Pseudomonas aeruginosa
D. Candida

Explanation: **Explanation:** **Escherichia coli (Option A)** is the most common cause of urinary tract infection (UTI) in children, accounting for approximately **80–90% of all cases**. The primary mechanism is the ascending route, where fecal flora colonize the perineum and enter the bladder. *E. coli* possesses specific virulence factors, such as **P-fimbriae (pyelonephritis-associated pili)**, which allow the bacteria to adhere to the uroepithelial cells and resist being washed away by urine flow. **Why other options are incorrect:** * **Klebsiella species (Option B):** While it is the second most common Gram-negative cause, it typically occurs in children with recurrent UTIs, those who have received prior antibiotics, or those with structural abnormalities. * **Pseudomonas aeruginosa (Option C):** This is an opportunistic pathogen. It is rarely a cause in healthy children and is usually associated with hospital-acquired infections, urinary tract instrumentation (catheterization), or chronic structural malformations. * **Candida (Option D):** Fungal UTIs are uncommon in immunocompetent children. They are typically seen in neonates in the NICU, children on prolonged broad-spectrum antibiotics, or those with indwelling catheters. **High-Yield Clinical Pearls for NEET-PG:** * **Most common route of infection:** Ascending route (except in neonates, where hematogenous spread is more common). * **Most common viral cause:** Adenovirus (typically causes acute hemorrhagic cystitis). * **Gold Standard Diagnosis:** Urine culture obtained via suprapubic aspiration (any growth is significant) or transurethral catheterization (>50,000 CFU/mL). * **Proteus mirabilis:** Often associated with UTIs in uncircumcised males and is linked to the formation of struvite (staghorn) calculi due to its urease-producing nature.

Question 2: A 10-year-old boy presents with hypertension. There is no other significant history. What is the most likely cause of his hypertension?

A. Chronic glomerulonephritis
B. Polycystic kidney disease (Correct Answer)
C. Reflux nephropathy
D. Renal parenchymal disease

Explanation: **Explanation:** In the pediatric population, hypertension is most commonly **secondary** to an underlying condition, with renal causes accounting for over 80% of cases. **Why Polycystic Kidney Disease (PKD) is the correct answer:** While "Renal Parenchymal Disease" is a broad category, **Autosomal Dominant Polycystic Kidney Disease (ADPKD)** is a specific and frequent cause of asymptomatic hypertension in older children (around age 10). Hypertension in PKD often precedes a significant decline in glomerular filtration rate (GFR) due to the activation of the Renin-Angiotensin-Aldosterone System (RAAS) caused by cyst expansion and local renal ischemia. In the context of a child presenting with *isolated* hypertension and no other history (like hematuria or edema), PKD is a high-yield diagnosis. **Analysis of Incorrect Options:** * **Chronic Glomerulonephritis:** Usually presents with a history of hematuria, proteinuria, or previous episodes of acute nephritic syndrome. * **Reflux Nephropathy:** Typically associated with a history of recurrent Urinary Tract Infections (UTIs) or voiding dysfunction, which is absent in this clinical vignette. * **Renal Parenchymal Disease:** This is a general umbrella term that includes glomerulonephritis, pyelonephritis, and PKD. In competitive exams like NEET-PG, when a specific disease entity (PKD) is provided alongside a general category, the specific diagnosis is preferred if it fits the clinical profile. **NEET-PG High-Yield Pearls:** * **Most common cause of HTN in children:** Renal Parenchymal Disease (overall). * **Most common cause of HTN in newborns:** Renal Artery Thrombosis (often due to umbilical artery catheterization). * **Gold Standard for diagnosis:** 24-hour Ambulatory Blood Pressure Monitoring (ABPM). * **First-line investigation:** Renal Ultrasound (to look for scars, cysts, or size discrepancies).

Question 3: A patient with congenital nephrotic syndrome requires which of the following procedures?

A. Live attenuated vaccines
B. Renal biopsy (Correct Answer)
C. High-dose steroids
D. Low-protein diet

Explanation: **Explanation:** **Congenital Nephrotic Syndrome (CNS)** is defined as the onset of nephrotic-range proteinuria, edema, and hypoalbuminemia within the first three months of life. **Why Renal Biopsy is the Correct Answer:** In CNS, a renal biopsy is a critical diagnostic step to differentiate between various underlying etiologies. While the most common cause is the **Finnish type (NPHS1 mutation)**, a biopsy helps rule out other structural or syndromic causes like Diffuse Mesangial Sclerosis (DMS) or secondary causes like congenital syphilis or CMV. Histopathology in the Finnish type typically shows characteristic microcystic dilatation of the proximal tubules. **Analysis of Incorrect Options:** * **Live Attenuated Vaccines:** These are generally **contraindicated** in patients with nephrotic syndrome who are on immunosuppressive therapy or are severely edematous/malnourished due to the risk of disseminated infection. * **High-dose Steroids:** Unlike Minimal Change Disease (MCD) in older children, CNS is **steroid-resistant**. The condition is caused by genetic mutations in podocyte proteins (e.g., Nephrin, Podocin), making steroid therapy ineffective and potentially toxic. * **Low-protein Diet:** Patients with CNS lose massive amounts of albumin in the urine. A low-protein diet would worsen the malnutrition and growth failure. Instead, these infants require a **high-protein, high-calorie diet** to compensate for urinary losses. **High-Yield Clinical Pearls for NEET-PG:** * **Finnish Type (NPHS1):** Most common cause; inherited as autosomal recessive; mutation in the **Nephrin** gene (chromosome 19q13). * **Antenatal Diagnosis:** Elevated **Alpha-fetoprotein (AFP)** levels in amniotic fluid or maternal serum. * **Management:** Definitive treatment is **bilateral nephrectomy** (to stop protein loss) followed by peritoneal dialysis and eventual **renal transplantation**.

Question 4: An 8-year-old child has had abdominal pain and dark urine for 10 days. Physical examination shows blotchy purple skin lesions on the trunk and extremities. Urinalysis shows hematuria and proteinuria. Serologic test results are negative for myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) and proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA). A skin biopsy specimen shows necrotizing vasculitis of small dermal vessels. A renal biopsy specimen shows immune complex deposition in glomeruli, with some IgA-rich immune complexes. Which of the following is the most likely diagnosis?

A. Giant cell arteritis
B. Henoch-Schonlein purpura (Correct Answer)
C. Polyarteritis nodosa
D. Takayasu arteritis

Explanation: **Explanation:** The clinical presentation of **abdominal pain, dark urine (hematuria), and palpable purpura** (blotchy purple lesions) in a child is the classic triad of **Henoch-Schönlein Purpura (HSP)**, now commonly referred to as **IgA Vasculitis**. **Why Option B is Correct:** HSP is a small-vessel vasculitis characterized by the deposition of **IgA-dominant immune complexes**. The skin biopsy showing necrotizing vasculitis of small dermal vessels (leukocytoclastic vasculitis) and the renal biopsy showing IgA-rich deposits in the mesangium are pathognomonic. The negative ANCA results help rule out ANCA-associated vasculitides like Granulomatosis with polyangiitis. **Why Other Options are Incorrect:** * **A & D (Giant cell & Takayasu arteritis):** These are **large-vessel vasculitides**. They typically present with absent pulses, bruits, or temporal headaches and do not feature IgA-mediated glomerulonephritis or small-vessel dermal vasculitis. * **C (Polyarteritis nodosa):** This is a **medium-vessel vasculitis**. While it can cause abdominal pain (mesenteric ischemia) and renal involvement, it typically spares the capillaries (glomeruli) and is not associated with IgA deposition. **High-Yield Clinical Pearls for NEET-PG:** * **Most common** systemic vasculitis in children. * **Classic Tetrad:** Palpable purpura (without thrombocytopenia), arthralgia, abdominal pain, and renal disease. * **Triggers:** Often follows an Upper Respiratory Tract Infection (URTI). * **Renal Pathology:** Identical to **IgA Nephropathy (Berger’s disease)**; however, HSP is a systemic multisystem involvement, whereas Berger’s is localized to the kidney. * **Treatment:** Usually supportive; steroids are used for severe gastrointestinal or renal involvement.

Question 5: After her first urinary tract infection (UTI), a 1-year-old girl has a voiding cystourethrogram with findings shown below. Which of the following is the most appropriate management option?

A. Low-dose daily antibiotics (Correct Answer)
B. Immediate surgical reimplantation of the ureters
C. Weekly urinalyses and culture
D. Diet low in protein

Explanation: ***Low-dose daily antibiotics*** - **Prophylactic antibiotics** are the first-line conservative management for **Grade II-III vesicoureteral reflux (VUR)** in young children to prevent recurrent UTIs and potential **renal scarring**. - This approach allows time for potential **spontaneous resolution** of VUR as the child grows, which commonly occurs in low-to-moderate grade reflux. *Immediate surgical reimplantation of the ureters* - **Ureteral reimplantation** is reserved for **high-grade VUR (Grade IV-V)** or cases with breakthrough infections despite prophylactic antibiotics. - **Grade II-III VUR** often resolves spontaneously with conservative management, making immediate surgery unnecessarily aggressive. *Weekly urinalyses and culture* - **Monitoring alone** without prophylaxis increases the risk of **recurrent UTIs** and potential **renal scarring** in a child with established VUR. - This approach fails to provide **active protection** against ascending infections that VUR predisposes the patient to. *Diet low in protein* - **Protein restriction** is indicated for **chronic kidney disease** with significant **renal impairment**, not for VUR management. - VUR with normal renal function does not require **dietary modifications**, and protein is essential for normal growth in children.

Question 6: Which of the following is NOT a characteristic of nephrotic syndrome in children?

A. Hypertension is not associated
B. Minimal change disease is common in children less than 10 years
C. Massive proteinuria is greater than 3.5 grams per 24 hours
D. Low complement levels are typically observed (Correct Answer)

Explanation: **Explanation:** The hallmark of **Minimal Change Disease (MCD)**, the most common cause of Nephrotic Syndrome in children, is that it is a **"pauci-immune"** condition. In typical childhood nephrotic syndrome, the complement system is not consumed; therefore, **serum complement levels (C3 and C4) remain normal.** Low complement levels should instead raise suspicion for nephritic conditions like Post-Streptococcal Glomerulonephritis (PSGN), Lupus Nephritis, or Membranoproliferative Glomerulonephritis (MPGN). **Analysis of Options:** * **Option A:** Hypertension is generally **not associated** with pure nephrotic syndrome (MCD). Its presence, along with hematuria, often suggests a "nephritic" component or a different pathology like FSGS. * **Option B:** **Minimal Change Disease** accounts for approximately 80-90% of cases in children under 10 years of age, making it the most common histological subtype in this demographic. * **Option C:** **Massive proteinuria** is the defining feature. In pediatric terms, this is defined as >40 mg/m²/hr or a spot protein:creatinine ratio >2. In adults, the threshold is >3.5 g/24 hours. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Nephrotic Syndrome (Children):** Minimal Change Disease (MCD). * **Most common cause of Nephrotic Syndrome (Adults):** Membranous Nephropathy (globally) or FSGS (increasingly common). * **MCD Morphology:** Light microscopy is normal; Electron microscopy shows **effacement of podocyte foot processes.** * **Treatment:** Corticosteroids (Prednisolone) are the first-line treatment. * **Indications for Renal Biopsy:** Age <1 year or >12 years, persistent hypertension, gross hematuria, or **low complement levels.**

Question 7: A 9-year-old boy presents with decreased urine output, cola-colored urine, and swelling of the face and hands for 2 days. He is hypertensive, has a puffy face, and pitting edema of the lower limbs. He had a history of skin lesions 4 weeks prior. A diagnosis of post-streptococcal glomerulonephritis is made. At what point are C3 levels likely to return to normal?

A. 2 weeks
B. 4 weeks
C. 8 weeks (Correct Answer)
D. 6 weeks

Explanation: **Explanation:** **1. Why Option C (8 weeks) is correct:** Post-streptococcal glomerulonephritis (PSGN) is an immune-complex-mediated disease (Type III hypersensitivity). The activation of the **alternative complement pathway** leads to the consumption of C3, resulting in low serum C3 levels in >90% of patients during the acute phase. A hallmark of PSGN is that these levels are **transient**. In a typical case, C3 levels begin to rise after the first week and return to the normal range within **6 to 8 weeks**. If C3 remains low beyond 8–12 weeks, alternative diagnoses like Membranoproliferative Glomerulonephritis (MPGN) or Systemic Lupus Erythematosus (SLE) must be considered. **2. Why other options are incorrect:** * **Options A & B (2 and 4 weeks):** While C3 levels start rising early, they usually remain below the normal reference range during the first month of the illness. * **Option D (6 weeks):** Although some patients may normalize by 6 weeks, **8 weeks** is the standard clinical benchmark used in textbooks (like Nelson Pediatrics) and exams to differentiate PSGN from chronic nephritic conditions. **3. High-Yield Clinical Pearls for NEET-PG:** * **Latent Period:** PSGN occurs 1–3 weeks after pharyngitis and 3–6 weeks after pyoderma (skin lesions). * **Sequence of Recovery:** 1. **Diuresis:** First sign of improvement (usually within 1 week). 2. **C3 Normalization:** Within 8 weeks. 3. **Hematuria:** Can persist for 6 months to 1 year. 4. **Proteinuria:** Usually disappears within 6 months. * **Gold Standard Diagnosis:** Renal biopsy (though rarely needed) shows "lumpy-bumpy" appearance on immunofluorescence and "subepithelial humps" on electron microscopy. * **C4 Levels:** Typically remain **normal** in PSGN (unlike SLE where both C3 and C4 are low).

Question 8: A 3-year-old child presents with 3+ proteinuria, oliguria, and edema. There is no hematuria. What is the most likely diagnosis?

A. Minimal change glomerulonephritis (Correct Answer)
B. Membranous glomerulonephritis
C. Mesangioproliferative glomerulonephritis
D. Rapidly progressive glomerulonephritis

Explanation: **Explanation:** The clinical presentation of **3+ proteinuria, edema, and oliguria** in a 3-year-old child is the classic triad of **Nephrotic Syndrome**. **1. Why Minimal Change Disease (MCD) is correct:** MCD is the most common cause of Nephrotic Syndrome in children (accounting for ~80% of cases). The hallmark of MCD is **"highly selective" proteinuria** (mainly albumin) due to the loss of the glomerular polyanion charge. Crucially, MCD typically presents **without hematuria, hypertension, or azotemia**, making it the most likely diagnosis in this pediatric case. **2. Why other options are incorrect:** * **Membranous Glomerulonephritis:** This is the most common cause of nephrotic syndrome in **adults**, not children. It is often associated with secondary causes like Hepatitis B or SLE. * **Mesangioproliferative Glomerulonephritis:** This often presents with a "nephritic-nephrotic" picture, frequently involving hematuria, which is absent here. * **Rapidly Progressive Glomerulonephritis (RPGN):** This is a **Nephritic Syndrome** characterized by a rapid decline in GFR, crescent formation on biopsy, and prominent hematuria/hypertension. **Clinical Pearls for NEET-PG:** * **Light Microscopy:** Glomeruli appear normal (hence "Minimal Change"). * **Electron Microscopy (Gold Standard):** Shows **effacement (fusion) of podocyte foot processes**. * **Treatment:** Highly steroid-responsive (Prednisolone is the drug of choice). * **Age Factor:** Peak incidence is between **2–6 years**. If a child presents with nephrotic syndrome under 1 year or over 10 years, consider non-MCD causes.

Question 9: A 10-year-old girl presents with polyuria and polydipsia, along with hypokalemia, hypercalciuria, and metabolic alkalosis. What is the probable diagnosis?

A. Gitelmann syndrome
B. Liddle syndrome
C. Bartter syndrome (Correct Answer)
D. Alport's syndrome

Explanation: ### Explanation **Bartter Syndrome** is the correct diagnosis because it typically presents in early childhood with the triad of **hypokalemia, metabolic alkalosis, and hypercalciuria**. It is caused by a defect in the thick ascending limb (TAL) of the Loop of Henle (specifically the NKCC2 transporter, ROMK, or ClC-Kb channels). This mimics the effect of **Loop diuretics** (Furosemide), leading to salt wasting, activation of the RAAS system, and increased urinary calcium excretion. #### Why the other options are incorrect: * **Gitelman Syndrome:** Often presents later (adolescence/adulthood). While it also features hypokalemia and metabolic alkalosis, it is characterized by **hypocalciuria** (low urinary calcium), mimicking **Thiazide diuretics**. * **Liddle Syndrome:** This is a "pseudoaldosteronism" caused by overactivity of ENaC channels. While it causes hypokalemia and alkalosis, it presents with **hypertension** and low renin/aldosterone levels. Bartter syndrome patients are typically normotensive. * **Alport’s Syndrome:** This is a collagen IV defect presenting with **hereditary nephritis (hematuria)**, sensorineural deafness, and ocular defects. It does not cause the electrolyte disturbances described. #### High-Yield Clinical Pearls for NEET-PG: * **Bartter vs. Gitelman:** The "Gold Standard" differentiator is urinary calcium. **Bartter = High/Normal Calcium**; **Gitelman = Low Calcium**. * **Mnemonic:** **B**artter is like a **B**oop (Loop) diuretic; **G**itelman is like a **G**iazide (Thiazide) diuretic. * **Antenatal Bartter:** Can present with polyhydramnios and severe salt wasting in the neonatal period. * **Treatment:** NSAIDs (to inhibit prostaglandins) and potassium-sparing diuretics/potassium supplements.

Question 10: A 2-year-old child presents with a 1-year history of generalized edema. His blood pressure is 107/70 mmHg. Urine examination shows hyaline casts and 3+ proteinuria, with no white blood cells or red blood cells. What is the likely diagnosis?

A. Selective proteinuria (Correct Answer)
B. Uremia
C. Focal segmental glomerulosclerosis
D. Low serum complement level

Explanation: **Explanation:** The clinical presentation of a 2-year-old with generalized edema and significant proteinuria (3+) without hematuria or hypertension (BP 107/70 mmHg is normal for this age) is classic for **Minimal Change Disease (MCD)**. MCD is the most common cause of Nephrotic Syndrome in children. The hallmark of MCD is **selective proteinuria**, meaning the glomerular basement membrane loses its negative charge (polyanionic charge barrier), allowing small, negatively charged proteins like **albumin** to leak through, while larger proteins (globulins) are retained. **Why other options are incorrect:** * **Uremia:** This refers to the clinical syndrome of advanced renal failure. In this case, the absence of hypertension or mentioned azotemia makes uremia unlikely at presentation. * **Focal Segmental Glomerulosclerosis (FSGS):** While FSGS also causes nephrotic syndrome, it often presents with **non-selective proteinuria**, hypertension, and microscopic hematuria, and is less common than MCD in a 2-year-old. * **Low serum complement level:** Serum C3 and C4 levels are **normal** in MCD and FSGS. Low complement is characteristic of "nephritic" conditions like Post-Streptococcal Glomerulonephritis (PSGN) or Lupus Nephritis. **Clinical Pearls for NEET-PG:** * **MCD Pathogenesis:** Effacement (fusion) of podocyte foot processes seen on Electron Microscopy. * **Light Microscopy:** Appears normal (hence "Minimal Change"). * **Treatment:** Highly steroid-sensitive; Prednisolone is the first-line treatment. * **Selective Proteinuria Index:** A ratio of IgG clearance to Albumin clearance <0.1 indicates highly selective proteinuria.

Practice by Chapter

Urinary Tract Infections

Practice Questions

Vesicoureteral Reflux

Practice Questions

Glomerulonephritis

Practice Questions

Nephrotic Syndrome

Practice Questions

Acute Kidney Injury

Practice Questions

Chronic Kidney Disease

Practice Questions

Renal Tubular Disorders

Practice Questions

Congenital Anomalies of the Kidney

Practice Questions

Hydronephrosis

Practice Questions

Hypertension in Children

Practice Questions

Hemolytic Uremic Syndrome

Practice Questions

Renal Replacement Therapy in Children

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free

Nephrology — MCQs

Nephrology — MCQs

On this page

Practice by Chapter

Want unlimited practice?