Nephrology — MCQs

Nephrology Indian Medical PG Practice Questions and MCQs

Question 81: Which immunoglobulin is found in Henoch-Schonlein Purpura?

A. IgA (Correct Answer)
B. IgM
C. IgG
D. IgE

Explanation: **Explanation:** **Henoch-Schönlein Purpura (HSP)**, now commonly referred to as **IgA Vasculitis**, is the most common systemic vasculitis in children. The hallmark of its pathogenesis is the deposition of immune complexes containing **galactose-deficient IgA1** in the walls of small vessels (capillaries, venules, and arterioles). 1. **Why IgA is Correct:** HSP is a Type III hypersensitivity reaction. The core pathology involves abnormal glycosylation of IgA1, leading to the formation of autoantibodies and subsequent immune complex deposition in the skin, joints, gastrointestinal tract, and kidneys. On renal biopsy, immunofluorescence characteristically shows **mesangial IgA deposition**, identical to what is seen in IgA Nephropathy (Berger’s disease). 2. **Why other options are incorrect:** * **IgM & IgG:** While these may occasionally be found as secondary components in the immune complexes, they are not the primary diagnostic or pathogenic drivers of HSP. * **IgE:** This immunoglobulin is associated with Type I hypersensitivity (atopy, asthma, anaphylaxis) and parasitic infections, not the systemic small-vessel vasculitis seen in HSP. **NEET-PG High-Yield Pearls:** * **Classic Tetrad:** Non-thrombocytopenic palpable purpura (usually on lower limbs/buttocks), arthritis/arthralgia, abdominal pain (intussusception is a known complication), and renal involvement. * **Diagnosis:** Primarily clinical. Platelet count will be **normal** (distinguishes it from ITP). * **Renal Prognosis:** The long-term prognosis of HSP depends entirely on the severity of renal involvement (HSP Nephritis). * **Treatment:** Mostly supportive; steroids are used for severe abdominal pain or significant renal involvement but do not prevent chronic kidney disease.

Question 82: Deficiency of abdominal muscles is associated with which of the following conditions?

A. Eagle-Barrette syndrome (Correct Answer)
B. Christopher syndrome
C. Megacystitis
D. Megaureter

Explanation: **Explanation:** The correct answer is **Eagle-Barrett Syndrome**, more commonly known as **Prune Belly Syndrome**. This is a rare congenital anomaly characterized by a classic triad: 1. **Deficiency of abdominal wall musculature:** This leads to the characteristic wrinkled, "prune-like" appearance of the overlying skin. 2. **Urinary tract abnormalities:** These typically include a large, thin-walled bladder (megacystitis), dilated ureters (megaureter), and renal dysplasia. 3. **Bilateral cryptorchidism:** Failure of the testes to descend into the scrotum. **Analysis of Options:** * **A. Eagle-Barrett Syndrome:** This is the definitive diagnosis for the triad mentioned above. The muscle deficiency is thought to result from fetal abdominal distension caused by early urinary tract obstruction. * **B. Christopher Syndrome:** This is not a recognized medical term related to abdominal wall defects or nephrology. * **C & D. Megacystitis and Megaureter:** While these are *components* or features of Eagle-Barrett syndrome, they are descriptive terms for dilated bladders and ureters, respectively. They can occur independently due to other obstructive pathologies (like Posterior Urethral Valves) and do not inherently imply a deficiency of abdominal muscles. **High-Yield Clinical Pearls for NEET-PG:** * **Epidemiology:** Occurs almost exclusively in **males** (95%). * **Associated Findings:** Often associated with pulmonary hypoplasia (due to oligohydramnios) and orthopedic deformities like clubfoot. * **Prognosis:** Depends largely on the degree of renal dysplasia and pulmonary hypoplasia. * **Radiology:** Voiding cystourethrogram (VCUG) often shows a dilated prostatic urethra and massive vesicoureteral reflux.

Question 83: An 8-month-old boy is referred for evaluation following a urinary tract infection. Ultrasound examination of the abdomen is normal. What is the most appropriate investigation to evaluate his lower urinary tract?

A. Radionuclide cystogram
B. Micturating cystourethrogram (Correct Answer)
C. Intravenous pyelogram
D. Cystoscopy

Explanation: **Explanation:** The investigation of choice for evaluating the lower urinary tract in a pediatric patient following a UTI is a **Micturating Cystourethrogram (MCUG)**, also known as a Voiding Cystourethrogram (VCUG). **Why MCUG is the Correct Choice:** MCUG is the gold standard for diagnosing **Vesicoureteral Reflux (VUR)** and visualizing the anatomy of the **urethra**. In a male infant, it is crucial to rule out **Posterior Urethral Valves (PUV)**, which can only be accurately identified during the voiding phase of this study. While ultrasound is a screening tool for hydronephrosis, it often misses VUR and urethral pathology, necessitating an MCUG for definitive evaluation. **Analysis of Incorrect Options:** * **Radionuclide Cystogram (RNC):** While it involves less radiation than MCUG, it provides poor anatomical detail. It is used for screening siblings or follow-up of known VUR, but it cannot diagnose PUV or other urethral abnormalities. * **Intravenous Pyelogram (IVP):** This primarily evaluates the upper urinary tract (kidneys and ureters). It is largely obsolete in pediatric UTI workups due to radiation and the superiority of USG and CT/MRU. * **Cystoscopy:** This is an invasive procedure. It is reserved for therapeutic interventions or when imaging is inconclusive; it is never the first-line investigation for a routine UTI workup. **Clinical Pearls for NEET-PG:** * **DMSA Scan:** The gold standard for detecting **renal scarring** (acute pyelonephritis). * **DTPA/MAG-3 Scan:** Used to evaluate renal function and **obstructive uropathy** (e.g., PUJ obstruction). * **AAP Guidelines:** Recommend an MCUG if the initial USG shows hydronephrosis, scarring, or if there is a recurrence of a febrile UTI. However, in the context of evaluating the *lower* tract specifically, MCUG remains the answer.

Question 84: A 3-year-old child presented with a history of abdominal mass, polyuria, and polydipsia. Investigations, including intravenous pyelography, revealed a streaky appearance of the kidneys. What is the chromosomal location of the gene involved in this condition?

A. 6p (Correct Answer)
B. 6q
C. 14p
D. 14q

Explanation: ### Explanation The clinical presentation described—a 3-year-old with an abdominal mass, polyuria, polydipsia, and a characteristic **"streaky appearance"** on intravenous pyelography (IVP)—is classic for **Autosomal Recessive Polycystic Kidney Disease (ARPKD)**. **1. Why 6p is Correct:** ARPKD is caused by a mutation in the **PKHD1 gene**, which is located on the **short arm of chromosome 6 (6p)**. This gene encodes **fibrocystin** (also known as polyductin), a protein found in the primary cilia of epithelial cells in the renal tubules and bile ducts. In ARPKD, the kidneys undergo fusiform dilation of the collecting ducts. On IVP, the contrast fills these dilated ducts, creating the pathognomonic **"sunburst" or "streaky" appearance**. Polyuria and polydipsia occur due to a defect in the concentrating ability of the distal tubules. **2. Why Other Options are Incorrect:** * **6q:** While the gene is on chromosome 6, it is specifically located on the short arm (p), not the long arm (q). * **14p/14q:** These locations are not associated with ARPKD. However, mutations in **PKD1** (Chromosome **16p**) and **PKD2** (Chromosome **4q**) are responsible for Autosomal Dominant Polycystic Kidney Disease (ADPKD), which typically presents in adulthood. **3. Clinical Pearls for NEET-PG:** * **Hepatic Involvement:** ARPKD is universally associated with **Congenital Hepatic Fibrosis**. If the patient survives the neonatal period, they often develop portal hypertension and splenomegaly. * **Potter Sequence:** Severe cases present at birth with pulmonary hypoplasia, limb deformities, and characteristic facies due to oligohydramnios. * **Ultrasound Finding:** Bilateral, symmetrically enlarged, echogenic ("bright") kidneys with loss of corticomedullary differentiation. * **Differential:** Unlike ADPKD, the cysts in ARPKD are microscopic and represent dilated collecting ducts, not discrete macrocysts.

Question 85: What is the diagnosis for pulmonary hypoplasia associated with uropathy?

A. Potter syndrome (Correct Answer)
B. Patau syndrome
C. Perthes disease
D. All of the above

Explanation: **Explanation:** **Potter Syndrome (Option A)** is the correct diagnosis. It refers to a distinct physical sequence resulting from **oligohydramnios** (low amniotic fluid). In cases of fetal uropathy (such as posterior urethral valves or bilateral renal agenesis), the fetus fails to excrete urine into the amniotic sac. Amniotic fluid is essential for lung development; its absence leads to **pulmonary hypoplasia**, which is the most common cause of death in these neonates. The lack of fluid also causes fetal compression, leading to "Potter facies" (flattened nose, recessed chin, low-set ears) and limb deformities. **Why other options are incorrect:** * **Patau Syndrome (Option B):** This is Trisomy 13, characterized by midline defects such as cleft lip/palate, holoprosencephaly, polydactyly, and microphthalmia, rather than a primary association with uropathy-induced lung hypoplasia. * **Perthes Disease (Option C):** Also known as Legg-Calvé-Perthes disease, this is an orthopedic condition involving avascular necrosis of the femoral head in children, unrelated to renal or pulmonary pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Potter Sequence (POTTER):** **P**ulmonary hypoplasia, **O**ligohydramnios, **T**wisted face (Potter facies), **T**wisted skin (wrinkled), **E**xtremity defects, **R**enal failure/agenesis. * The most common cause of Potter sequence is **Bilateral Renal Agenesis**. * In males, **Posterior Urethral Valves (PUV)** is a frequent obstructive uropathy leading to this sequence. * **Key finding on X-ray:** Small thoracic volume with bell-shaped chest.

Question 86: Which of the following gene mutations can lead to idiopathic steroid-resistant nephrotic syndrome?

A. NPHS1
B. NPHS2
C. WT1
D. All of the above (Correct Answer)

Explanation: **Explanation:** Steroid-resistant nephrotic syndrome (SRNS) is frequently caused by genetic mutations affecting the **podocyte architecture** or the **glomerular basement membrane**. Unlike steroid-sensitive cases (often Minimal Change Disease), genetic SRNS does not respond to immunosuppression because the defect is structural, not immunological. * **NPHS1 (Option A):** This gene encodes **Nephrin**, a key transmembrane protein of the slit diaphragm. Mutations in *NPHS1* lead to **Finnish-type Congenital Nephrotic Syndrome**, which typically presents within the first three months of life and is characteristically resistant to steroids. * **NPHS2 (Option B):** This gene encodes **Podocin**. Mutations in *NPHS2* are the most common cause of autosomal recessive familial SRNS and are frequently associated with **Focal Segmental Glomerulosclerosis (FSGS)** on biopsy. * **WT1 (Option C):** The **Wilms Tumor 1** gene is essential for podocyte development. Mutations here can lead to isolated SRNS or syndromic forms like **Denys-Drash Syndrome** (characterized by SRNS, male pseudohermaphroditism, and Wilms tumor) and **Frasier Syndrome**. Since all three genes are well-documented causes of idiopathic SRNS, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Congenital Nephrotic Syndrome:** Defined as onset within 0–3 months of age. *NPHS1* is the most common mutation. * **Infantile Nephrotic Syndrome:** Onset between 4–12 months. *NPHS2* and *PLCE1* are common. * **Management Tip:** Patients with confirmed genetic mutations (like *NPHS2*) should generally avoid prolonged steroid toxicity, as the likelihood of response is near zero. Genetic testing is recommended for all children with SRNS.

Question 87: What is the most common cause of severe obstructive uropathy in neonates?

A. Prune-Belly syndrome
B. Bladder neck obstruction
C. Posterior urethral valves (Correct Answer)
D. None of these

Explanation: **Explanation:** **Posterior Urethral Valves (PUV)** is the most common cause of lower urinary tract obstruction (LUTO) in male neonates and the leading cause of severe obstructive uropathy in the neonatal period. It occurs due to the presence of abnormal congenital mucosal folds in the prostatic urethra, which act as a valve, impeding the outflow of urine from the bladder. * **Why Option C is correct:** PUV leads to high-pressure urinary retention, causing secondary bladder wall hypertrophy, bilateral hydroureteronephrosis, and potentially irreversible renal dysplasia. It is a frequent cause of chronic kidney disease (CKD) in children. * **Why Option A is incorrect:** Prune-Belly syndrome (Eagle-Barrett syndrome) is a rare triad of abdominal muscle deficiency, undescended testes, and urinary tract abnormalities. While it involves uropathy, it is significantly less common than PUV. * **Why Option B is incorrect:** Bladder neck obstruction is a rare cause of neonatal uropathy and is usually a diagnosis of exclusion or associated with neurogenic bladder rather than a primary obstructive anatomical entity like PUV. **High-Yield Clinical Pearls for NEET-PG:** 1. **Antenatal Presentation:** Often detected on ultrasound as bilateral hydronephrosis, a distended thick-walled bladder, and the characteristic **"Keyhole sign"** (dilated posterior urethra). 2. **Clinical Sign:** A neonate with a **poor/dribbling urinary stream** and a palpable midline abdominal mass (distended bladder). 3. **Gold Standard Investigation:** **Voiding Cystourethrogram (VCUG)** is the definitive diagnostic test. 4. **Immediate Management:** Bladder drainage via a feeding tube/catheter, followed by definitive surgical management (Endoscopic Valve Ablation).

Question 88: What is the most common cause of end-stage renal disease (ESRD) in children?

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

Explanation: **Explanation:** **Nephronophthisis (NPHP)** is the most common genetic cause of end-stage renal disease (ESRD) in children and adolescents. It is an autosomal recessive tubulointerstitial cystic kidney disease. Unlike adult-onset renal failure, which is often driven by glomerular diseases or diabetes, pediatric ESRD is frequently caused by **ciliopathies** and congenital anomalies of the kidney and urinary tract (CAKUT). NPHP typically presents with a triad of polyuria, polydipsia, and anemia, leading to progressive renal failure by the first or second decade of life. **Analysis of Options:** * **Nephronophthisis (Correct):** It is the leading inherited cause of pediatric ESRD. On ultrasound, kidneys appear normal-sized or small with increased echogenicity and loss of corticomedullary differentiation; cysts are usually small and located at the corticomedullary junction. * **ADPKD (Incorrect):** While it is the most common inherited kidney disease overall, it typically manifests in **adulthood** (4th–5th decade). It rarely causes ESRD during childhood. * **Medullary Cystic Disease (Incorrect):** Now often referred to as Autosomal Dominant Tubulointerstitial Kidney Disease (ADTKD), it is clinically similar to NPHP but presents in **adults** (mean age of ESRD is 30–50 years). * **ARPKD (Incorrect):** Although it presents in infancy or childhood with massive bilateral kidney enlargement, it is statistically less common as a cause of ESRD compared to the NPHP group of disorders. **Clinical Pearls for NEET-PG:** * **Key Triad:** Polyuria, Polydipsia, and Anemia (due to early erythropoietin deficiency) in a child with a "bland" urine sediment (no blood/protein). * **Senior-Løken Syndrome:** NPHP associated with Retinitis Pigmentosa (High-yield association). * **Imaging:** Unlike polycystic diseases, NPHP usually features **small to normal-sized kidneys.**

Question 89: Wilm's tumor is associated with all of the following conditions EXCEPT:

A. Hemihypertrophy
B. Aniridia
C. Hypertension
D. Bilateral polycystic kidney (Correct Answer)

Explanation: **Explanation:** Wilms tumor (Nephroblastoma) is the most common primary renal malignancy in children. It is frequently associated with specific congenital malformations and genetic syndromes, but **Bilateral Polycystic Kidney Disease (BPKD)** is not one of them. BPKD is a genetic ciliopathy and does not predispose patients to Wilms tumor. **Analysis of Options:** * **A. Hemihypertrophy:** This is a classic association, often seen in **Beckwith-Wiedemann Syndrome (BWS)**. BWS is characterized by macroglossia, omphalocele, and organomegaly. Children with isolated hemihypertrophy have an increased risk of embryonal tumors like Wilms and hepatoblastoma. * **B. Aniridia:** Absence of the iris is a hallmark of the **WAGR syndrome** (Wilms tumor, Aniridia, Genitourinary anomalies, and intellectual disability/Range of developmental delays). This results from a microdeletion on chromosome 11p13 involving the *WT1* and *PAX6* genes. * **C. Hypertension:** Hypertension is present in about 25% of Wilms tumor cases. It occurs due to increased **renin production** by the tumor cells or compression of the renal artery by the tumor mass (Goldblatt phenomenon). **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common presentation:** An asymptomatic, large, smooth abdominal mass that **does not cross the midline** (unlike Neuroblastoma). 2. **Denys-Drash Syndrome:** Characterized by the triad of Wilms tumor, male pseudohermaphroditism, and early-onset renal failure (diffuse mesangial sclerosis). 3. **Genetics:** Associated with mutations on **Chromosome 11** (*WT1* at 11p13 and *WT2* at 11p15). 4. **Staging:** Wilms tumor is staged surgically. The most common site of distant metastasis is the **Lungs**.

Question 90: All are features of hemolytic uremic syndrome, except?

A. Hyperkalemia
B. Anemia
C. Renal microthrombi
D. Neuropsychiatric disturbances (Correct Answer)

Explanation: **Explanation:** Hemolytic Uremic Syndrome (HUS) is a clinical triad characterized by **Microangiopathic Hemolytic Anemia (MAHA)**, **Thrombocytopenia**, and **Acute Kidney Injury (AKI)**. It most commonly follows a prodromal diarrheal illness caused by Shiga toxin-producing *E. coli* (STEC), specifically serotype O157:H7. **Why Option D is the Correct Answer:** While HUS can occasionally present with mild neurological symptoms (like irritability or lethargy) due to uremia or electrolyte imbalances, **Neuropsychiatric disturbances** are a hallmark feature of **Thrombotic Thrombocytopenic Purpura (TTP)**, not HUS. TTP is defined by a "pentad" that includes the HUS triad plus fever and prominent neurological involvement. In pediatric HUS, the pathology is primarily localized to the renal vasculature. **Analysis of Incorrect Options:** * **Option A (Hyperkalemia):** This is a common complication of HUS. As the kidneys fail (AKI), they lose the ability to excrete potassium. Additionally, the hemolysis of red blood cells releases intracellular potassium into the bloodstream. * **Option B (Anemia):** MAHA is a core component of the HUS triad. It occurs as RBCs are sheared while passing through narrowed, fibrin-clotted small vessels, leading to the presence of **schistocytes** (helmet cells) on a peripheral smear. * **Option C (Renal microthrombi):** The underlying pathophysiology involves endothelial injury leading to the formation of platelet-fibrin microthrombi within the glomerular capillaries and afferent arterioles. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Anemia + Thrombocytopenia + Renal Failure. * **Peripheral Smear:** Look for **Schistocytes** and a high LDH. * **Management:** Primarily supportive (fluids, dialysis). **Antibiotics and anti-motility agents are contraindicated** in STEC-HUS as they may increase toxin release and worsen the condition. * **Atypical HUS:** Caused by uncontrolled complement activation (Factor H deficiency); treated with **Eculizumab**.

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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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