Nephrology Practice Questions

Q: What is the recommended fluid administration rate in an infant weighing 10 kg?

4 ml/kg/hr. The correct answer is **4 ml/kg/hr** based on the standard **Holliday-Segar Formula**, which is the gold standard for calculating maintenance fluid requirements in pediatric patients. ### **Medical Concept: The 4-2-1 Rule** The Holliday-Segar method estimates caloric expenditure to determine fluid needs. For hourly maintenance rates, we use the **4-2-1 Rule**: * **First 10 kg:** 4 ml/kg/hr * **Next 10 kg (11–20 kg):** Add 2 ml/kg/hr * **Each kg above 20 kg:** Add 1 ml/kg/hr For an infant weighing **10 kg**, the calculation is simply: $10 \text{ kg} \times 4 \text{ ml/kg/hr} = 40 \text{ ml/hr}$. ### **Analysis of Options** * **Option A (1 ml/kg/hr):** This is the rate for every kg **above 20 kg**. For a 10 kg infant, this would lead to severe dehydration. * **Option B (2 ml/kg/hr):** This is the incremental rate for the **second 10 kg** of body weight (11–20 kg range). * **Option C (3 ml/kg/hr):** This does not correspond to any standard step in the 4-2-1 maintenance formula. * **Option D (4 ml/kg/hr):** Correct. This is the standard hourly rate for the first 10 kg of body weight. ### **High-Yield Clinical Pearls for NEET-PG** 1. **Daily Requirements:** If the question asks for daily (24h) fluid, use the **100-50-20 rule** (100 ml/kg for the first 10 kg). For this infant, it would be 1000 ml/day. 2. **Isotonic Fluids:** Recent guidelines (AAP) recommend **Isotonic solutions** (e.g., 0.9% Normal Saline) with 5% Dextrose as maintenance fluid in hospitalized children to prevent iatrogenic hyponatremia. 3. **Exceptions:** Maintenance rates are reduced in conditions with SIADH or oliguric renal failure and increased in cases of fever or burns.

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

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

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

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

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

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

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

Syndrome of inappropriate antidiuretic hormone (SIADH). **Explanation:** Hyponatremia (Serum Sodium <135 mEq/L) is the most common electrolyte abnormality encountered in hospitalized children. **Why SIADH is the correct answer:** The **Syndrome of Inappropriate Antidiuretic Hormone (SIADH)** is considered the most common cause of hyponatremia in the pediatric population, particularly in hospitalized patients. It is characterized by the non-physiological release of ADH despite low serum osmolality and normal blood volume. In children, this is frequently triggered by **CNS infections (meningitis, encephalitis)**, **pulmonary conditions (pneumonia)**, and **post-operative stress**. The excess ADH leads to water retention and dilutional hyponatremia. **Analysis of Incorrect Options:** * **A. Excessive sweating:** While sweating leads to loss of sodium and water, it is typically a **hypernatremic** process because sweat is hypotonic (more water is lost than sodium). * **B. Vomiting:** This causes hypovolemic hyponatremia due to fluid loss and subsequent ADH release (non-osmotic trigger). While common, it is statistically less frequent than SIADH-mediated hyponatremia in clinical settings. * **D. Diuretic use:** This is a common cause in elderly patients (especially thiazides) but is a relatively rare cause of hyponatremia in the general pediatric population. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Euvolemic Hyponatremia:** SIADH. * **Diagnostic Criteria for SIADH:** Low serum osmolality ( 100 mOsm/kg), and high urine sodium (>20-40 mEq/L) in a euvolemic patient. * **Management:** Fluid restriction is the first-line treatment for SIADH. * **Danger:** Rapid correction of chronic hyponatremia can lead to **Central Pontine Myelinolysis (Osmotic Demyelination Syndrome).**

Q: A 3-year-old child presents with a four-day history of facial puffiness, fever, and tea-colored urine. What is the most likely complication the child will NOT experience?

Hypokalemia. ### Explanation The clinical presentation of a 3-year-old with facial puffiness, fever, and tea-colored urine (hematuria) is classic for **Acute Post-Streptococcal Glomerulonephritis (PSGN)**. PSGN is a nephritic syndrome characterized by a sudden decrease in the Glomerular Filtration Rate (GFR). **Why Hypokalemia is NOT expected:** In acute glomerulonephritis, the primary pathology is glomerular inflammation leading to a **decreased GFR**. This results in the retention of water, sodium, and metabolic waste products. Because the kidneys cannot effectively excrete potassium, the typical electrolyte abnormality is **Hyperkalemia**, not hypokalemia. Therefore, Option A is the correct answer as it is the complication the child will NOT experience. **Analysis of other options:** * **Hypertensive Encephalopathy (B):** Fluid overload and renin-angiotensin system activation lead to hypertension. If blood pressure rises rapidly, it can cause cerebral edema, leading to seizures or altered sensorium. * **Acute Renal Failure (C):** Severe inflammation can lead to a significant drop in GFR, resulting in oliguria and azotemia (elevated urea/creatinine), fulfilling the criteria for acute kidney injury. * **Acidosis (D):** With a reduced GFR, the kidneys fail to excrete hydrogen ions and regenerate bicarbonate, leading to **Metabolic Acidosis**. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Group A Beta-hemolytic Streptococcus (Post-pharyngeal or post-pyodermal). * **Latent period:** 1–2 weeks after pharyngitis; 3–6 weeks after skin infection (impetigo). * **Hallmark Lab Finding:** Low **C3 complement levels** (returns to normal in 6–8 weeks). * **Microscopy:** RBC casts are pathognomonic; "Lumpy-bumpy" appearance on immunofluorescence (IgG and C3 deposits). * **Management:** Primarily supportive (fluid restriction and diuretics). Antibiotics do not prevent PSGN but limit the spread of the nephritogenic strain.

Q: What is the most common cause of abdominal swelling in a newborn?

Multicystic dysplastic kidney. **Explanation:** In the neonatal period, the most common cause of a palpable abdominal mass is of **renal origin** (approximately 55% of cases). Among these, **Multicystic Dysplastic Kidney (MCDK)** is the most frequent cause of a neonatal abdominal swelling/mass. **1. Why Multicystic Dysplastic Kidney (MCDK) is correct:** MCDK results from the abnormal induction of the metanephric blastema by the ureteric bud, leading to a non-functioning kidney filled with multiple non-communicating cysts of varying sizes. It typically presents as a unilateral, irregular, flank mass in an otherwise healthy newborn. It is often detected during routine prenatal ultrasound. **2. Why the other options are incorrect:** * **Autosomal Recessive Polycystic Kidney Disease (ARPKD):** While it presents in the neonatal period with bilateral flank masses and "Potter sequence" features, it is significantly less common than MCDK. * **Autosomal Dominant Polycystic Kidney Disease (ADPKD):** This typically manifests in adulthood (3rd to 5th decade). While a "very-early onset" form exists, it is rare in newborns. * **Horseshoe Kidney:** This is the most common renal fusion anomaly, but it is usually asymptomatic and rarely presents as a palpable abdominal swelling in a newborn unless associated with hydronephrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common neonatal abdominal mass:** MCDK. * **Most common cause of neonatal hydronephrosis:** Pelviureteric Junction (PUJ) Obstruction. * **Most common malignant abdominal tumor in neonates:** Neuroblastoma (though Wilms tumor is more common in older children). * **Management of MCDK:** Most cases are managed conservatively with serial ultrasounds, as many undergo spontaneous involution. The contralateral kidney must be monitored for compensatory hypertrophy or associated VUR (Vesicoureteral Reflux).

Q: A seven-year-old asymptomatic girl is found to have persistent hypertension. There is no significant family history and urine examination is normal. Which of the following is the most likely cause?

Renal Parenchymal Disease. **Explanation:** In pediatric practice, the rule of thumb is that the younger the child and the higher the blood pressure, the more likely it is to be **secondary hypertension**. **1. Why Renal Parenchymal Disease is correct:** Renal Parenchymal Disease (e.g., chronic glomerulonephritis, reflux nephropathy, or scarring from previous UTIs) is the **most common cause of secondary hypertension in children**, accounting for approximately 60-80% of cases. While the question states the urine examination is currently normal, many parenchymal diseases (like reflux nephropathy or focal segmental glomerulosclerosis in early stages) can present with persistent hypertension before significant proteinuria or hematuria becomes constant. **2. Analysis of Incorrect Options:** * **Essential Hypertension:** While increasing in prevalence due to childhood obesity, it is typically a diagnosis of exclusion and is more common in adolescents (older children) with a positive family history. * **Polycystic Kidney Disease (ADPKD/ARPKD):** While a cause of hypertension, it usually presents with palpable abdominal masses or a significant family history (in ADPKD), which are absent here. * **Coarctation of the Aorta:** This is a classic cause of upper limb hypertension, but it is usually associated with diminished/delayed femoral pulses and a systolic murmur, making it less likely than renal causes in an asymptomatic 7-year-old. **Clinical Pearls for NEET-PG:** * **Most common cause of HTN in children:** Renal Parenchymal Disease. * **Most common renovascular cause:** Fibromuscular Dysplasia (FMD) or Takayasu Arteritis (in India). * **Initial Investigation:** Renal Ultrasound with Doppler is often the first-line imaging to rule out parenchymal and vascular causes. * **Definition:** Hypertension in children is defined as Systolic or Diastolic BP **≥95th percentile** for age, sex, and height on three separate occasions.

Question 1

What is the recommended fluid administration rate in an infant weighing 10 kg?

Accepted Answer

4 ml/kg/hr

Answer

1 ml/kg/hr

Answer

2 ml/kg/hr

Answer

3 ml/kg/hr

Question 2

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

Accepted Answer

Group A beta-hemolytic streptococci

Answer

Escherichia coli

Answer

Epstein-Barr virus

Answer

Klebsiella sp.

Question 3

What condition carries a high risk of renal dysplasia?

Accepted Answer

Posterior urethral valve

Answer

Bladder exstrophy

Answer

Anorectal malformation

Answer

Neonatal sepsis

Question 4

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

Accepted Answer

1 and 2 are true, 3 and 4 are false

Answer

1 and 4 are true, 2 and 3 are false

Answer

3 and 4 are true, 1 and 2 are false

Answer

2 and 3 are false, 1 and 4 are true

Question 5

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

Accepted Answer

All the above

Answer

Urine albumin >40 mg/m2/hr

Answer

Spot urine protein : creatinine ratio >2

Answer

Urine dipstick 3+ or 4+

Question 6

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

Accepted Answer

Pauci-immune glomerulonephritis

Answer

Goodpasture syndrome

Answer

Membranous glomerulonephritis

Answer

IgA nephropathy

Question 7

What is the most common cause of hyponatremia in children?

Accepted Answer

Syndrome of inappropriate antidiuretic hormone (SIADH)

Answer

Excessive sweating

Answer

Vomiting

Answer

Diuretic use

Question 8

A 3-year-old child presents with a four-day history of facial puffiness, fever, and tea-colored urine. What is the most likely complication the child will NOT experience?

Accepted Answer

Hypokalemia

Answer

Hypertensive encephalopathy

Answer

Acute renal failure

Answer

Acidosis

Question 9

What is the most common cause of abdominal swelling in a newborn?

Accepted Answer

Multicystic dysplastic kidney

Answer

Autosomal dominant polycystic kidney disease

Answer

Autosomal recessive polycystic kidney disease

Answer

Horseshoe kidney

Question 10

A seven-year-old asymptomatic girl is found to have persistent hypertension. There is no significant family history and urine examination is normal. Which of the following is the most likely cause?

Accepted Answer

Renal Parenchymal Disease

Answer

Essential Hypertension

Answer

Polycystic Kidney Disease

Answer

Coarctation of the Aorta

Nephrology — MCQs

Nephrology — MCQs

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