Nephrology — MCQs

A 9-year-old child has had steroid-dependent nephrotic syndrome for the last 5 years. He has received corticosteroids almost continuously during this period and has Cushingoid features. His blood pressure is 120/86 mmHg, and there are bilateral subcapsular cataracts. What is the treatment of choice?

Q168Medium

A 10-year-old boy with nephrotic syndrome developed peritonitis. Which of the following organisms is most commonly responsible?

Q169Easy

What is the commonest cause of enuresis in children?

Q170Medium

Which of the following is NOT true about multicystic dysplastic kidney disease?

Nephrology Indian Medical PG Practice Questions and MCQs

Question 161: In Henoch-Schönlein purpura, which of the following findings is NOT typically present?

A. Abdominal pain with proteinuria
B. Acute arthritis
C. Rectal bleeding
D. More common in adults (Correct Answer)

Explanation: **Explanation:** Henoch-Schönlein Purpura (HSP), now commonly referred to as **IgA Vasculitis**, is the most common systemic vasculitis of childhood. **Why Option D is the correct answer:** HSP is primarily a pediatric disease. Approximately 90% of cases occur in children, with a peak incidence between **3 and 10 years of age**. While it can occur in adults, it is significantly less common in that population, though adult-onset HSP often carries a more severe prognosis regarding renal involvement. **Analysis of Incorrect Options:** * **Option A (Abdominal pain with proteinuria):** Gastrointestinal involvement occurs in ~75% of cases due to submucosal hemorrhage and edema. Renal involvement (HSP Nephritis) occurs in ~30-50% of patients, typically presenting as hematuria or **proteinuria**. * **Option B (Acute arthritis):** This is the second most common feature (seen in ~75%). It typically involves large joints (knees and ankles) and is transient and non-deforming. * **Option C (Rectal bleeding):** GI symptoms can range from colicky pain to occult blood or frank **melena/hematochezia** (rectal bleeding). In severe cases, it can lead to intussusception (typically ileo-ileal). **High-Yield Clinical Pearls for NEET-PG:** * **Classic Tetrad:** Non-thrombocytopenic palpable purpura (essential for diagnosis), arthritis, abdominal pain, and renal disease. * **Pathogenesis:** Deposition of **IgA1-dominant immune complexes** in small vessels. * **Preceding Event:** Often follows an Upper Respiratory Tract Infection (URTI), specifically Group A Strep. * **Platelet Count:** Always **normal** (distinguishes it from ITP). * **Biopsy:** Skin biopsy shows **Leukocytoclastic vasculitis**; Renal biopsy is identical to **IgA Nephropathy (Berger’s disease)**.

Question 162: Joubert syndrome is associated with which of the following conditions?

A. Autosomal dominant polycystic kidney disease
B. Medullary cystic kidney disease
C. Nephronophthisis (Correct Answer)
D. Autosomal recessive polycystic kidney disease

Explanation: **Explanation:** **Joubert Syndrome** is a rare autosomal recessive neurodevelopmental disorder characterized by the **"Molar Tooth Sign"** on MRI, which results from cerebellar vermis hypoplasia and midbrain malformations. It belongs to a group of disorders called **ciliopathies**—conditions caused by defects in the structure or function of primary cilia. **Why Nephronophthisis is correct:** Nephronophthisis (NPHP) is the most common genetic cause of end-stage renal disease (ESRD) in children and adolescents. It is a ciliopathy characterized by tubulointerstitial fibrosis and cyst formation at the corticomedullary junction. Because Joubert Syndrome and NPHP share common genetic pathways involving ciliary proteins, approximately 25–30% of patients with Joubert Syndrome develop NPHP (often referred to as **Joubert Syndrome Related Disorders** or JSRD). **Why other options are incorrect:** * **ADPKD (Option A):** Caused by mutations in *PKD1* or *PKD2* genes. It typically presents in adulthood with large, bilateral multicystic kidneys and is not classically associated with the Molar Tooth Sign. * **Medullary Cystic Kidney Disease (Option B):** Now termed Autosomal Dominant Tubulointerstitial Kidney Disease (ADTKD). While histologically similar to NPHP, it is inherited in an autosomal dominant pattern and presents later in life without the syndromic features of Joubert. * **ARPKD (Option C):** Characterized by *PKHD1* mutations and presents with bilateral enlarged echogenic kidneys and congenital hepatic fibrosis. While it is a ciliopathy, it is not the primary renal association for Joubert Syndrome. **High-Yield Clinical Pearls for NEET-PG:** * **Molar Tooth Sign:** Pathognomonic MRI finding in Joubert Syndrome (elongated superior cerebellar peduncles). * **Clinical Triad of Joubert:** Hypotonia, ataxia, and developmental delay, often with episodic hyperpnea/apnea. * **Senior-Løken Syndrome:** The association of Nephronophthisis with Retinitis Pigmentosa. * **Nephronophthisis vs. Polycystic Kidney Disease:** In NPHP, kidneys are usually **normal or small** in size, whereas in PKD, kidneys are **enlarged**.

Question 163: A 6-year-old child presents with recurrent episodes of gross hematuria for 2 years. What is the most likely diagnosis?

A. IgA nephropathy (Correct Answer)
B. Wilm's tumor
C. Henoch-Schonlein Purpura (HSP)
D. Neuroblastoma

Explanation: **Explanation:** The clinical presentation of **recurrent episodes of gross hematuria** in a child is the hallmark of **IgA Nephropathy (Berger’s Disease)**. It is the most common cause of primary glomerulonephritis worldwide. The hematuria is typically "synpharyngitic," meaning it occurs simultaneously with or within 1–2 days of an upper respiratory tract infection (URTI). Between episodes, the child is usually asymptomatic, though microscopic hematuria may persist. **Analysis of Options:** * **A. IgA Nephropathy (Correct):** Characterized by episodic macroscopic hematuria triggered by mucosal infections (URTI or GI infections) due to the deposition of abnormally glycosylated IgA1 in the glomerular mesangium. * **B. Wilm’s Tumor:** While it can cause hematuria, it typically presents as a large, smooth, palpable abdominal mass that does not cross the midline. Recurrent episodes over two years without a mass are highly unlikely. * **C. Henoch-Schönlein Purpura (HSP):** Though related to IgA (IgA vasculitis), HSP presents with a classic tetrad: palpable purpura (lower limbs), arthralgia, abdominal pain, and renal involvement. Isolated recurrent hematuria without systemic symptoms points toward IgA nephropathy. * **D. Neuroblastoma:** This is a sympathetic chain tumor. It usually presents with a painful, irregular abdominal mass crossing the midline, opsoclonus-myoclonus, or systemic symptoms (fever, weight loss). Hematuria is rare. **High-Yield Clinical Pearls for NEET-PG:** * **Synpharyngitic Hematuria:** IgA Nephropathy (occurs <3 days after URTI). * **Post-infectious Hematuria (PSGN):** Occurs 1–3 weeks after URTI/Skin infection (latent period). * **Diagnosis:** Gold standard is **Renal Biopsy**, showing mesangial hypercellularity and IgA deposits on Immunofluorescence. * **Prognosis:** Most common indicator of poor prognosis is persistent hypertension and significant proteinuria.

Question 164: Which of the following conditions is NOT typically steroid-resistant?

A. Post-streptococcal glomerulonephritis
B. Minimal change glomerulonephritis (Correct Answer)
C. Rapidly progressive glomerulonephritis
D. Recurrent hematuria

Explanation: **Explanation:** The core of this question lies in distinguishing between **Nephrotic Syndrome** and **Nephritic Syndrome** regarding their response to corticosteroid therapy. **Why Minimal Change Disease (MCD) is the correct answer:** Minimal Change Disease (also known as Minimal Change Glomerulonephritis) is the most common cause of Nephrotic Syndrome in children. It is characterized by the effacement of podocyte foot processes. The hallmark of MCD is its **exquisite sensitivity to steroids**. Over 90% of children with MCD achieve complete remission within 4–8 weeks of Prednisolone therapy. Therefore, it is the definition of a steroid-responsive condition, not a steroid-resistant one. **Analysis of Incorrect Options:** * **Post-streptococcal Glomerulonephritis (PSGN):** This is an immune-complex-mediated nephritic syndrome. Management is primarily supportive (managing hypertension and edema). Steroids have no proven role in its treatment; thus, the disease process itself does not respond to them. * **Rapidly Progressive Glomerulonephritis (RPGN):** While high-dose "pulse" steroids are used to dampen the intense inflammation, RPGN is often aggressive and frequently progresses to renal failure despite therapy. It is generally categorized under conditions that are difficult to treat and do not show the classic "steroid-sensitive" pattern seen in MCD. * **Recurrent Hematuria:** This is a clinical presentation (often associated with IgA Nephropathy or Alport Syndrome). Most causes of isolated recurrent hematuria do not require or respond to steroid therapy. **NEET-PG High-Yield Pearls:** * **Definition of Steroid Responsiveness:** Remission (protein-free urine for 3 consecutive days) achieved within 8 weeks of therapy. * **MCD Pathology:** Light microscopy is normal; Electron microscopy shows **podocyte foot process effacement**. * **Most common cause of Steroid-Resistant Nephrotic Syndrome (SRNS):** Focal Segmental Glomerulosclerosis (FSGS). * **First-line treatment for MCD:** Oral Prednisolone (2 mg/kg/day).

Question 165: How does Wilms tumor commonly present in children?

A. Hematuria
B. Abdominal pain
C. Abdominal mass (Correct Answer)
D. Fever

Explanation: **Explanation:** **Wilms Tumor (Nephroblastoma)** is the most common primary renal malignancy in children, typically occurring between the ages of 2 and 5 years. **Why "Abdominal Mass" is correct:** The hallmark presentation of Wilms tumor is a **painless, firm, smooth, and unilateral abdominal mass**. In approximately 80% of cases, this mass is discovered incidentally by a parent while bathing or dressing the child, or during a routine physical examination. Unlike Neuroblastoma, the mass in Wilms tumor typically **does not cross the midline** as it originates within the renal parenchyma. **Analysis of Incorrect Options:** * **A. Hematuria:** While microscopic hematuria occurs in about 25% of cases, gross hematuria is rare. It is a secondary finding rather than the primary presenting complaint. * **B. Abdominal pain:** Pain is present in only about 25–30% of patients, usually due to rapid tumor growth or hemorrhage within the tumor. * **D. Fever:** Fever is a constitutional symptom seen in only 10–20% of cases and is not the most common presenting feature. **High-Yield Clinical Pearls for NEET-PG:** * **Hypertension:** Present in 25% of cases due to increased renin production. * **WAGR Syndrome:** Wilms tumor, Aniridia, Genitourinary anomalies, and intellectual disability (Range of developmental delay). Associated with **WT1 gene** deletion on chromosome 11p13. * **Beckwith-Wiedemann Syndrome:** Macroglossia, hemihypertrophy, and omphalocele. Associated with **WT2 gene** on chromosome 11p15. * **Management Tip:** Avoid vigorous palpation of the abdomen to prevent rupture of the renal capsule and subsequent tumor spillage (upstaging).

Question 166: A child presents with steroid-resistant nephrotic syndrome secondary to focal segmental glomerulosclerosis (FSGS) that is not responsive to methylprednisolone. What is the next recommended treatment?

A. Oral cyclophosphamide
B. Oral cyclosporine (Correct Answer)
C. Oral mycophenolate mofetil
D. Intravenous cyclophosphamide

Explanation: **Explanation:** The management of Steroid-Resistant Nephrotic Syndrome (SRNS), most commonly caused by Focal Segmental Glomerulosclerosis (FSGS), follows a standardized protocol. When a patient fails to respond to corticosteroids (including pulse methylprednisolone), the **first-line treatment of choice is a Calcineurin Inhibitor (CNI), specifically Oral Cyclosporine.** **Why Oral Cyclosporine is Correct:** Cyclosporine acts by inhibiting T-cell activation and stabilizing the podocyte cytoskeleton, which reduces proteinuria. Clinical trials (including those by the ISKDC) have shown that CNIs are superior to alkylating agents in inducing remission in SRNS. According to KDIGO and Indian Society of Pediatric Nephrology (ISPN) guidelines, Cyclosporine (or Tacrolimus) should be initiated for a minimum of 6 months to assess response. **Why Other Options are Incorrect:** * **A & D (Cyclophosphamide):** While alkylating agents are effective for Steroid-Dependent or Frequently Relapsing Nephrotic Syndrome, they have a very low success rate in SRNS/FSGS. Both oral and IV routes are generally avoided as initial therapy for resistance due to poor efficacy and gonadal toxicity. * **C (Mycophenolate Mofetil):** MMF is typically considered a second-line steroid-sparing agent or used as maintenance therapy *after* remission is induced. It is less effective than Cyclosporine for initial induction in SRNS. **High-Yield Clinical Pearls for NEET-PG:** * **Definition of SRNS:** Failure to achieve remission after 4 weeks of daily prednisolone (2 mg/kg/day). * **Gold Standard Investigation:** A renal biopsy is mandatory in all cases of SRNS before starting CNI therapy to confirm FSGS and assess chronicity. * **Side Effects of Cyclosporine:** Gingival hyperplasia, hirsutism, hypertension, and nephrotoxicity (requires monitoring of trough levels). * **Alternative CNI:** Tacrolimus is an alternative to Cyclosporine, preferred if cosmetic side effects (hirsutism) are a concern.

Question 167: A 9-year-old child has had steroid-dependent nephrotic syndrome for the last 5 years. He has received corticosteroids almost continuously during this period and has Cushingoid features. His blood pressure is 120/86 mmHg, and there are bilateral subcapsular cataracts. What is the treatment of choice?

A. Levamisole
B. Cyclophosphamide (Correct Answer)
C. Cyclosporin A
D. Intravenous pulse corticosteroids

Explanation: **Explanation:** The patient presents with **Steroid-Dependent Nephrotic Syndrome (SDNS)** complicated by significant steroid toxicity, including Cushingoid features, hypertension, and bilateral subcapsular cataracts. In such cases, the primary goal is to induce a long-term remission while sparing the patient from further steroid exposure. **Why Cyclophosphamide is the treatment of choice:** According to standard pediatric nephrology guidelines (ISPN), **Cyclophosphamide** (an alkylating agent) is the preferred first-line steroid-sparing agent for SDNS, especially when there are signs of steroid toxicity. It is typically administered at a dose of 2 mg/kg/day for 8–12 weeks. It has a high success rate in inducing prolonged remission and reducing the frequency of relapses, thereby allowing the withdrawal of corticosteroids. **Analysis of Incorrect Options:** * **Levamisole (A):** While used in SDNS, it is a weaker immunomodulator. In a patient with established severe toxicity (cataracts/hypertension), a more potent agent like Cyclophosphamide is preferred to ensure rapid steroid withdrawal. * **Cyclosporin A (C):** This is a Calcineurin Inhibitor (CNI) used for steroid-resistant cases or when Cyclophosphamide fails. It is generally reserved as a second-line steroid-sparing agent because it requires long-term use and carries risks of nephrotoxicity and gingival hyperplasia. * **IV Pulse Corticosteroids (D):** This would exacerbate the existing steroid toxicity (cataracts and hypertension) and is not a definitive treatment for dependency. **NEET-PG High-Yield Pearls:** * **Steroid-Dependent:** Two consecutive relapses during corticosteroid therapy or within 14 days of cessation. * **Frequent Relapser:** Two or more relapses in 6 months, or four or more in 12 months. * **Cyclophosphamide Toxicity:** Monitor for hemorrhagic cystitis (prevented by hydration) and gonadal toxicity (dose-dependent). * **Cataracts:** Posterior subcapsular cataracts are a classic side effect of long-term systemic steroid use in children.

Question 168: A 10-year-old boy with nephrotic syndrome developed peritonitis. Which of the following organisms is most commonly responsible?

A. E. coli
B. Klebsiella
C. Group A streptococci (Correct Answer)
D. Bacteroides fragilis

Explanation: **Explanation:** Spontaneous Bacterial Peritonitis (SBP) is a common and serious complication in children with Nephrotic Syndrome, particularly during a relapse. **1. Why Group A Streptococci is correct:** In the pediatric population with nephrotic syndrome, the most common causative organism for SBP is **Streptococcus pneumoniae** (Pneumococcus). However, in many standardized exams and classic textbooks, **Group A Streptococci (Streptococcus pyogenes)** is also frequently cited as a primary Gram-positive culprit. These organisms gain entry due to the patient's immunocompromised state, characterized by low levels of immunoglobulins (IgG), loss of complement factors (Factor B and D) in urine, and impaired opsonization. **2. Why the other options are incorrect:** * **E. coli & Klebsiella:** While Gram-negative organisms (like *E. coli*) are the most common cause of SBP in **adults with cirrhosis**, they are traditionally the second most common cause in children with nephrosis. * **Bacteroides fragilis:** Anaerobic infections are extremely rare in SBP. The presence of anaerobes usually suggests secondary peritonitis (e.g., bowel perforation) rather than spontaneous infection. **Clinical Pearls for NEET-PG:** * **Most Common Organism Overall:** *Streptococcus pneumoniae* is the #1 cause of SBP in nephrotic children. * **Shift in Trends:** Recent studies show an increasing incidence of Gram-negative infections (like *E. coli*), but for exam purposes, Gram-positive cocci remain the classic answer. * **Mechanism:** The susceptibility is primarily due to **hypogammaglobulinemia** and decreased **alternative complement pathway** activity. * **Clinical Sign:** A child with nephrotic syndrome presenting with fever and abdominal pain should be investigated for SBP immediately.

Question 169: What is the commonest cause of enuresis in children?

A. Urinary tract infection
B. Spina bifida
C. Psychologic stress
D. None of the above (Correct Answer)

Explanation: ### Explanation The correct answer is **None of the above** because the commonest cause of enuresis (specifically primary nocturnal enuresis) is **maturational delay** in the development of bladder control, often associated with a positive family history. #### Why "None of the above" is correct: Most cases of enuresis (80-90%) are **Primary Nocturnal Enuresis (PNE)**, where the child has never been dry for a period of 6 months. The underlying pathophysiology is usually multifactorial, involving: 1. **Maturational delay** of the CNS (bladder-brain signaling). 2. **Nocturnal polyuria** (due to relative deficiency of ADH secretion at night). 3. **Reduced functional bladder capacity** or detrusor overactivity. 4. **Genetics:** If both parents were enuretic, there is a 77% chance for the child. #### Why other options are incorrect: * **A. Urinary tract infection:** While UTI can cause *secondary* enuresis (new onset after being dry), it is a pathological cause and not the most common etiology overall. * **B. Spina bifida:** This is a structural/neurological cause (neurogenic bladder). It is a rare cause compared to the high prevalence of functional enuresis in the general pediatric population. * **C. Psychologic stress:** Stress is a significant trigger for **Secondary Enuresis** (e.g., birth of a sibling, divorce), but it is not the primary cause of the more common "primary" type. #### NEET-PG High-Yield Pearls: * **Definition:** Involuntary voiding of urine at least **twice a week** for at least **3 consecutive months** in a child at least **5 years** of age. * **Initial Management:** Behavioral modification (fluid restriction after 6 PM, bladder training, and "lifting"). * **Most Effective Long-term Treatment:** Enuresis/Bed-wetting **alarms** (highest success rate, lowest relapse). * **Drug of Choice (DOC):** **Desmopressin (DDAVP)** is used for rapid symptomatic relief (e.g., for camps). **Imipramine** (TCA) is a second-line option but has a high side-effect profile.

Question 170: Which of the following is NOT true about multicystic dysplastic kidney disease?

A. Unilateral multicystic dysplastic kidney is more common than bilateral.
B. Prognosis is good if MCDK is isolated and unilateral.
C. Unilateral MCDK leads to Potter sequence. (Correct Answer)
D. Bilateral MCDK has a poor prognosis.

Explanation: **Explanation:** **Multicystic Dysplastic Kidney (MCDK)** is a non-inherited developmental anomaly where the renal parenchyma is replaced by multiple non-communicating cysts, resulting in a non-functional kidney. **Why Option C is the correct answer (False statement):** Potter sequence is a constellation of physical findings (flattened facies, clubbed feet, pulmonary hypoplasia) caused by **severe oligohydramnios** (lack of amniotic fluid). Since amniotic fluid is primarily produced by fetal urine, Potter sequence only occurs when there is **bilateral** renal agenesis or dysfunction. In **unilateral MCDK**, the contralateral (other) kidney is usually functional and produces enough urine to maintain normal amniotic fluid levels; therefore, it does **not** lead to Potter sequence. **Analysis of other options:** * **Option A:** True. Unilateral MCDK is the most common form of cystic renal disease in newborns. * **Option B:** True. If the condition is isolated and the other kidney is healthy, the prognosis is excellent, as one functional kidney is sufficient for normal life. * **Option D:** True. Bilateral MCDK is incompatible with life, leading to severe oligohydramnios, pulmonary hypoplasia, and neonatal death (Potter sequence). **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Failure of the ureteric bud to integrate with the metanephric blastema. * **Associated Anomaly:** The most common associated abnormality is **Vesicoureteral Reflux (VUR)** in the contralateral (normal-appearing) kidney (seen in ~30% of cases). * **Management:** Most cases undergo spontaneous involution. Serial ultrasounds are the standard of care; nephrectomy is rarely required. * **Diagnostic Test:** **Renal Scintigraphy (DMSA scan)** shows a "non-visualizing" or "cold" kidney due to lack of function.

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Urinary Tract Infections

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Vesicoureteral Reflux

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Glomerulonephritis

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Nephrotic Syndrome

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Acute Kidney Injury

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Chronic Kidney Disease

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Renal Tubular Disorders

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Congenital Anomalies of the Kidney

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Hydronephrosis

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Hypertension in Children

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Hemolytic Uremic Syndrome

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Renal Replacement Therapy in Children

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Nephrology — MCQs

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