Nephrology Practice Questions

Q: A 13-year-old boy is referred for evaluation of nocturnal enuresis and short stature. His blood pressure is normal. The hemoglobin level is 8 g/dL, urea 112 mg/dL, creatinine 6 mg/dL, sodium 119 mEq/dL, potassium 4 mEq/L, calcium 7 mg/dL, phosphate 6 mg/dL, and alkaline phosphatase 300 U/L. Urinalysis shows trace proteinuria with hyaline casts; no red and white cells are seen. Ultrasound shows bilateral small kidneys, and the micturating cystourethrogram is normal. What is the most likely diagnosis?

Nephronophthisis. **Explanation:** The clinical presentation of a child with **short stature, nocturnal enuresis (polyuria), and progressive renal failure** (elevated urea/creatinine) with **bilateral small kidneys** and a bland urinary sediment is classic for **Nephronophthisis (NPHP)**. **Why Nephronophthisis is correct:** NPHP is an autosomal recessive tubulointerstitial cystic kidney disease and the most common genetic cause of End-Stage Renal Disease (ESRD) in children. * **Polyuria/Polydipsia:** Defective urinary concentration leads to nocturnal enuresis. * **Salt Wasting:** The low sodium (119 mEq/dL) reflects the inability of the tubules to conserve salt. * **Bland Sediment:** Unlike glomerulonephritis, NPHP shows minimal proteinuria and no hematuria. * **Imaging:** Small, echogenic kidneys are characteristic (unlike Medullary Cystic Kidney Disease, which presents in adults). **Why other options are incorrect:** * **Alport’s Syndrome:** Typically presents with persistent microscopic hematuria, sensorineural deafness, and ocular defects (lenticonus). * **Medullary Sponge Kidney:** Usually an asymptomatic incidental finding in adults; it is associated with nephrolithiasis and hypercalciuria, not early-onset ESRD or small kidneys. * **Chronic Glomerulonephritis:** Would typically present with significant proteinuria, active urinary sediment (RBC casts), and often hypertension, which is absent here. **NEET-PG High-Yield Pearls:** * **NPHP + Retinitis Pigmentosa** = Senior-Løken Syndrome. * **NPHP + Cerebellar Ataxia** = Joubert Syndrome. * **Key Triad:** Polyuria, growth retardation, and anemia out of proportion to renal failure (due to decreased erythropoietin from interstitial damage). * **Biopsy:** Characterized by the "tubulointerstitial triad": tubular basement membrane thickening/disruption, tubular atrophy, and interstitial fibrosis.

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

Unilateral MCDK leads to Potter sequence.. **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.

Q: What is the most common cause of hydronephrosis in children?

Pelviureteric junction (PUJ) obstruction. **Explanation:** **Pelviureteric Junction (PUJ) Obstruction** is the most common cause of congenital hydronephrosis in children. It occurs due to an anatomical or functional narrowing at the junction where the renal pelvis meets the ureter, leading to impaired urine flow and subsequent dilatation of the renal pelvis and calyces. **Analysis of Options:** * **A. PUJ Obstruction (Correct):** It is the leading cause of both neonatal and pediatric hydronephrosis. It is most commonly unilateral and often detected on antenatal ultrasound. * **B. Ureterocele:** This is a cystic dilation of the distal ureter. While it can cause hydroureteronephrosis, it is much less common than PUJ obstruction. * **C. Posterior Urethral Valve (PUV):** This is the most common cause of **bilateral** hydronephrosis in **male** infants. While clinically significant and a common cause of bladder outlet obstruction, its overall incidence is lower than PUJ obstruction. * **D. Ectopic Ureters:** These occur when the ureter terminates outside the bladder trigone. While they can cause obstruction or reflux, they are a relatively rare cause of hydronephrosis. **Clinical Pearls for NEET-PG:** * **Most common cause of unilateral hydronephrosis:** PUJ Obstruction. * **Most common cause of bilateral hydronephrosis in males:** Posterior Urethral Valve (PUV). * **Gold standard investigation for PUJ Obstruction:** DTPA or MAG-3 scan (Diuretic Renography) to assess the degree of obstruction and renal function. * **Classic Presentation:** Often asymptomatic (detected antenatally) or may present as a palpable flank mass or episodic "Dietl’s crisis" (intermittent flank pain associated with high fluid intake).

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

Posterior urethral valves. **Explanation:** **Posterior Urethral Valves (PUV)** are the most common cause of bladder outlet obstruction and urinary retention in male children. They consist of abnormal congenital mucosal folds within the prostatic urethra that act as a one-way valve, impeding the flow of urine. This leads to high intravesical pressures, bladder hypertrophy, and secondary vesicoureteral reflux (VUR), which can eventually cause renal dysplasia. **Analysis of Options:** * **Posterior Urethral Valves (Correct):** It is the classic "high-yield" cause of obstructive uropathy in boys. It typically presents with a poor urinary stream, a palpable midline bladder, and potentially a "keyhole sign" on prenatal ultrasound. * **Urethral Stenosis/Stricture:** While it can cause retention, it is much less common in children than PUV and is often secondary to trauma or instrumentation rather than being a primary congenital cause. * **Urethral Aplasia:** This is an extremely rare condition where the urethra fails to develop. It is usually incompatible with life unless an alternative drainage route (like a patent urachus) exists. * **Ectopic Ureteric Opening:** This typically presents with urinary incontinence (dribbling) in females or recurrent infections, rather than acute urinary retention. **Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Voiding Cystourethrogram (VCUG) is the investigation of choice (shows a dilated posterior urethra and a narrow stream). * **Initial Management:** Immediate bladder decompression using a small-feeding tube (catheterization). * **Definitive Treatment:** Endoscopic primary valve ablation (fulguration). * **Radiological Sign:** The "Keyhole Sign" on ultrasound (dilated bladder + dilated posterior urethra).

Q: A child with vesicoureteric reflux of grade 2 presents to the outpatient department. What is the preferred treatment method?

Antibiotics. **Explanation:** Vesicoureteric Reflux (VUR) is the retrograde flow of urine from the bladder into the ureter. The management of VUR is primarily determined by the **Grade of Reflux** (International Classification I-V) and the presence of symptoms. **Why Antibiotics is the Correct Answer:** For **Low-grade VUR (Grades I and II)**, the standard of care is **Medical Management** with Continuous Antibiotic Prophylaxis (CAP). The underlying concept is that low-grade reflux has a high rate of **spontaneous resolution** as the child grows and the ureterovesical junction matures. Antibiotics (e.g., Trimethoprim-Sulfamethoxazole or Nitrofurantoin) are used to maintain sterile urine and prevent recurrent Urinary Tract Infections (UTIs), thereby protecting the kidneys from pyelonephritis and scarring while waiting for resolution. **Analysis of Incorrect Options:** * **Observation:** While some modern protocols debate the necessity of CAP in toilet-trained children without infections, the standard textbook management for a child presenting with VUR remains antibiotic prophylaxis to prevent renal damage. * **Sting Operation (Sub-ureteric Teflon/Deflux Injection):** This is a minimally invasive endoscopic procedure reserved for Grade III-IV reflux or cases where medical management fails. * **Ureteric Reimplantation:** This is a surgical intervention (e.g., Cohen’s or Politano-Leadbetter technique) indicated for **High-grade VUR (Grades IV and V)**, bilateral reflux, or failure of medical therapy. **Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Voiding Cystourethrogram (VCUG/MCU). * **Initial Investigation for UTI in children:** Ultrasound (to look for hydronephrosis). * **Most common cause of secondary VUR:** Posterior Urethral Valves (PUV). * **Indication for Surgery:** Breakthrough UTIs despite antibiotics, non-compliance, or Grade V reflux with scarring.

Q: Nephrotic range of proteinuria is defined as:

greater than 40 mg/m2/hr. **Explanation:** In pediatric nephrology, defining the severity of proteinuria is crucial for diagnosing Nephrotic Syndrome. The hallmark of this condition is "massive" or **nephrotic-range proteinuria**, which leads to hypoalbuminemia and subsequent edema. **Why Option B is correct:** The standard definition for nephrotic-range proteinuria in children is a protein excretion rate of **>40 mg/m²/hr**. This value is derived from timed urine collections and is the most precise metric used in clinical guidelines (such as ISPN and KDIGO) to differentiate nephrotic syndrome from milder forms of glomerular injury. **Analysis of Incorrect Options:** * **Option A (>30 mg/m²/hr):** This is a sub-nephrotic range. While abnormal, it does not meet the diagnostic threshold for Nephrotic Syndrome. * **Option C (>2 gm/m²/24hrs):** While 1 gram/m²/24hrs is sometimes used as a threshold for "heavy" proteinuria, the specific diagnostic cutoff for nephrotic range is generally cited as **>1 gram/m²/day** or more accurately **>50 mg/kg/day**. 2 grams is an arbitrary figure in this context. * **Option D (>4 gm/m²/24hrs):** This value is excessively high and far exceeds the minimum diagnostic criteria. **High-Yield Clinical Pearls for NEET-PG:** * **Spot Urine Protein/Creatinine Ratio (uPCR):** In clinical practice, a ratio of **>2 mg/mg** (or >200 mg/mmol) is considered nephrotic range. * **Dipstick Grading:** Nephrotic syndrome typically shows **3+ or 4+** on a urine dipstick. * **Definition of Nephrotic Syndrome:** It is a clinical triad of Nephrotic-range proteinuria, Hypoalbuminemia (<2.5 g/dL), and Edema. Hyperlipidemia is a frequent association but not always required for diagnosis. * **Normal Proteinuria:** In children, normal protein excretion is **<4 mg/m²/hr**.

Q: Which of the following is NOT true about Bartter syndrome?

Hyperkalemic metabolic alkalosis. **Explanation:** **Bartter syndrome** is a group of autosomal recessive disorders characterized by a defect in the thick ascending limb (TAL) of the loop of Henle, mimicking the effect of chronic loop diuretic (furosemide) use. **1. Why Option A is the correct answer (The False Statement):** The hallmark of Bartter syndrome is **Hypokalemic metabolic alkalosis**, not hyperkalemic. The defect in the TAL leads to failure of sodium, chloride, and potassium reabsorption. The resulting increased sodium delivery to the distal tubule triggers aldosterone secretion, which promotes potassium and hydrogen ion excretion in the collecting duct, leading to hypokalemia and metabolic alkalosis. **2. Analysis of Incorrect Options (True Statements):** * **Option B:** Antenatal/Neonatal Bartter syndrome (Type IV) is caused by mutations in the **BSND gene (encoding Barttin)**. This type is uniquely associated with sensorineural deafness (ototoxicity) because Barttin is essential for chloride channels in both the kidney and the inner ear. * **Option C:** The primary pathophysiology involves a defect in the **NKCC2 transporter**, ROMK channel, or ClC-Kb channel, all of which result in decreased potassium and solute reabsorption in the TAL. * **Option D:** Most forms of Bartter syndrome (Types I-IV) follow an **autosomal recessive** inheritance pattern. **High-Yield Clinical Pearls for NEET-PG:** * **Bartter vs. Gitelman:** Bartter presents early (infancy) with **hypercalciuria** (stones), whereas Gitelman presents later (adolescence) with **hypocalciuria** and hypomagnesemia. * **Mnemonic:** **B**artter is like **B**loop (Loop diuretics); **G**itelman is like **G**thiazide (Thiazide diuretics). * **Clinical Features:** Polyhydramnios (antenatal), failure to thrive, and "floppy baby" due to hypokalemia.

Q: A newborn male presents with urinary retention, lethargy and a distended bladder. Antenatal ultrasound showed a "keyhole sign" with a thickened bladder wall. Which of the following is the most likely diagnosis?

Posterior urethral valves. ***Posterior urethral valves***- The **"keyhole sign"** seen on antenatal ultrasound, characterized by a dilated posterior urethra and a thickened, distended bladder, is highly specific for **posterior urethral valves (PUV)**.- PUV is the most common cause of severe **lower urinary tract obstruction** in male newborns, leading directly to symptoms like lethargy, a palpable **distended bladder**, and urinary retention.*Hypospadias*- *Hypospadias* is an abnormal location of the **urethral meatus** on the ventral aspect of the penis.- It does not cause the severe **obstructive uropathy** (like urinary retention and bladder distension) or the **keyhole sign** observed in this patient.*Vesicoureteral reflux*- *Vesicoureteral reflux* (VUR) involves the reflux of urine from the bladder back up to the ureters and is typically a **non-obstructive** cause of hydronephrosis and UTIs.- While VUR can coexist with PUV, it is the secondary phenomenon, and VUR itself does not cause the primary **urethral obstruction** or the characteristic **keyhole appearance**.*Neurogenic bladder*- A *neurogenic bladder* results from impaired nerve supply, often due to conditions like **spina bifida**, leading to poor bladder emptying.- While it can cause retention, the unique finding of the **keyhole sign** points specifically to a fixed, **anatomical obstruction** in the posterior urethra, which is not characteristic of neurological issues.

Q: What is the recommended treatment for nephrotic syndrome in children?

Steroids. ***Steroids***- **Corticosteroids** (typically Prednisone/Prednisolone) are the recommended **first-line therapy** for pediatric nephrotic syndrome, as *minimal change disease* (**MCD**) is the most common cause (90% of cases).- The vast majority of children with MCD are **steroid-sensitive**, exhibiting remission (proteinuria cessation) within 2-4 weeks of high-dose treatment.*Steroids and cyclophosphamide*- Combination therapy including **cyclophosphamide** is typically reserved for children who show **steroid dependence** or **frequent relapses**, not for initial therapy.- Adding cyclophosphamide as a first-line agent is unnecessary due to its potential for significant **gonadal toxicity** and other systemic side effects.*Cyclophosphamide*- **Cyclophosphamide** is a powerful **second-line immunosuppressive agent** used primarily for children who are steroid-dependent or **steroid-resistant**.- Using it as initial monotherapy is inappropriate because children with MCD usually respond well to steroids alone, avoiding risks like **myelosuppression**.*ACE inhibitors*- **Angiotensin-converting enzyme (ACE) inhibitors** are used primarily to reduce **proteinuria** by lowering **glomerular hydrostatic pressure**.- Their role is generally adjunctive management for resistant proteinuria or for treating associated **hypertension**, not as the primary agent to induce remission.

Question 1

A 13-year-old boy is referred for evaluation of nocturnal enuresis and short stature. His blood pressure is normal. The hemoglobin level is 8 g/dL, urea 112 mg/dL, creatinine 6 mg/dL, sodium 119 mEq/dL, potassium 4 mEq/L, calcium 7 mg/dL, phosphate 6 mg/dL, and alkaline phosphatase 300 U/L. Urinalysis shows trace proteinuria with hyaline casts; no red and white cells are seen. Ultrasound shows bilateral small kidneys, and the micturating cystourethrogram is normal. What is the most likely diagnosis?

Accepted Answer

Nephronophthisis

Answer

Alport's syndrome

Answer

Medullary sponge kidney

Answer

Chronic glomerulonephritis

Question 2

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

Accepted Answer

Unilateral MCDK leads to Potter sequence.

Answer

Unilateral multicystic dysplastic kidney is more common than bilateral.

Answer

Prognosis is good if MCDK is isolated and unilateral.

Answer

Bilateral MCDK has a poor prognosis.

Question 3

What is the most common cause of hydronephrosis in children?

Accepted Answer

Pelviureteric junction (PUJ) obstruction

Answer

Ureterocele

Answer

Posterior urethral valve

Answer

Ectopic ureter

Question 4

What is the most common cause of urinary retention in children?

Accepted Answer

Posterior urethral valves

Answer

Urethral stenosis

Answer

Urethral aplasia

Answer

Ectopic ureteric opening

Question 5

A child with vesicoureteric reflux of grade 2 presents to the outpatient department. What is the preferred treatment method?

Accepted Answer

Antibiotics

Answer

Observation

Answer

Sting operation

Answer

Ureteric reimplantation

Question 6

Nephrotic range of proteinuria is defined as:

Accepted Answer

greater than 40 mg/m2/hr

Answer

greater than 30 mg/m2/hr

Answer

greater than 2 gm/m2/24hrs

Answer

greater than 4 gm/m2/24hrs

Question 7

Which of the following is NOT true about Bartter syndrome?

Accepted Answer

Hyperkalemic metabolic alkalosis

Answer

Presentation in neonates with ototoxicity and Barttin gene mutation

Answer

Decreased potassium absorption from the thick ascending limb of the loop of Henle

Answer

Autosomal recessive inheritance

Question 8

What is the daily water requirement for a child weighing 30 kg, with a height of 123 cm, and a body surface area (BSA) of 1 m²?

Accepted Answer

1700 ml

Answer

1300 ml

Answer

2000 ml

Answer

2500 ml

Question 9

A newborn male presents with urinary retention, lethargy and a distended bladder. Antenatal ultrasound showed a "keyhole sign" with a thickened bladder wall. Which of the following is the most likely diagnosis?

Accepted Answer

Posterior urethral valves

Answer

Hypospadias

Answer

Vesicoureteral reflux

Answer

Neurogenic bladder

Question 10

What is the recommended treatment for nephrotic syndrome in children?

Accepted Answer

Steroids

Answer

ACE inhibitors

Answer

Cyclophosphamide

Answer

Steroids and cyclophosphamide

Nephrology — MCQs

Nephrology — MCQs

On this page

Practice by Chapter

Want unlimited practice?