Nephrology Practice Questions

Q: Which of the following nasal sprays is very effective in the control of enuresis?

Desmopressin. **Explanation:** **Desmopressin (DDAVP)** is the correct answer because it is a synthetic analogue of the antidiuretic hormone (ADH/Vasopressin). In the management of nocturnal enuresis, it works by binding to **V2 receptors** in the renal collecting ducts, increasing water reabsorption and reducing the volume of urine produced overnight to less than the functional bladder capacity. It is particularly effective in children with "nocturnal polyuria." While available as an oral melt or tablet, the nasal spray was historically the first-line delivery method (though its use in children is now more cautious due to the risk of hyponatremia). **Analysis of Incorrect Options:** * **A. Pitressin:** This is a sterile solution of synthetic Vasopressin. Unlike Desmopressin, it acts on both V1 (vasoconstriction) and V2 receptors. Its short half-life and significant pressor effects make it unsuitable for the long-term management of enuresis. * **C. Lipressin:** This is Lysine-vasopressin. It has a shorter duration of action and more pronounced pressor (V1) effects compared to Desmopressin, making it less effective and less safe for treating bedwetting. **High-Yield Clinical Pearls for NEET-PG:** * **First-line management:** Always start with behavioral modifications (fluid restriction, bladder training) and **Enuresis Alarms** (highest long-term cure rate). * **Desmopressin:** Provides the most rapid symptomatic relief; ideal for short-term use (e.g., camps or sleepovers). * **Side Effect Warning:** The most serious side effect of Desmopressin is **hyponatremic encephalopathy**. Patients must restrict fluid intake 1 hour before and 8 hours after administration. * **Imipramine:** A TCA used as a second-line drug for enuresis but carries a risk of cardiotoxicity in overdose.

Q: Which of the following would be the plasma osmolality of a child with plasma Na+ 125 mEq/L, glucose of 108 mg/dL, and blood urea nitrogen (BUN) of 140 mg/dL?

306 mOsm/kg. To calculate the plasma osmolality, we use the standard clinical formula which accounts for the primary osmotically active particles in the blood: Sodium, Glucose, and Blood Urea Nitrogen (BUN). ### **The Formula** **Calculated Plasma Osmolality = 2 × [Na⁺] + [Glucose / 18] + [BUN / 2.8]** ### **Step-by-Step Calculation** 1. **Sodium component:** 2 × 125 = **250** 2. **Glucose component:** 108 / 18 = **6** 3. **BUN component:** 140 / 2.8 = **50** 4. **Total:** 250 + 6 + 50 = **306 mOsm/kg** ### **Why Option B is Correct** Option B (**306 mOsm/kg**) is the precise result of the calculation. Despite the child having hyponatremia (Na+ 125), the significantly elevated BUN (140 mg/dL)—likely due to renal failure—contributes substantially to the total osmolality, bringing it into the hyperosmolar range. ### **Why Other Options are Incorrect** * **Options A, C, and D** are incorrect because they result from mathematical errors or using incorrect divisors (e.g., forgetting to divide glucose by 18 or BUN by 2.8). In NEET-PG, examiners often provide options that would be reached if a student used 5.6 instead of 2.8 for BUN or failed to double the Sodium value. ### **High-Yield Clinical Pearls for NEET-PG** * **Effective Osmolality (Tonicity):** This excludes urea because urea is a "permeable solute" that crosses cell membranes freely. The formula for effective osmolality is: **2 × [Na⁺] + [Glucose / 18]**. * **Osmolar Gap:** This is the difference between *measured* osmolality (via laboratory osmometer) and *calculated* osmolality. A gap >10 mOsm/L suggests the presence of unmeasured substances like ethanol, methanol, or ethylene glycol. * **Normal Range:** Normal plasma osmolality typically ranges from **275–295 mOsm/kg**.

Q: Which of the following is a true statement about pyelonephritis in children?

All of the above.. **Explanation:** Pyelonephritis in the pediatric population often presents with a clinical spectrum that varies significantly by age, making a high index of suspicion crucial for diagnosis. * **Option A (Neonates):** In neonates and young infants, the clinical presentation is notoriously **non-specific**. Instead of localized urinary symptoms, they often present with systemic signs such as irritability, poor feeding, lethargy, jaundice, or vomiting. * **Option B (Flank Pain):** As children grow older (typically school-age and adolescents), they are better able to localize pain. In these age groups, classic signs of upper urinary tract involvement, such as **flank pain and costovertebral angle tenderness**, become common findings. * **Option C (Fever of Unknown Cause):** Urinary Tract Infection (UTI) is one of the most common bacterial causes of **Fever Without a Source (FWS)** in children under 2 years. Current guidelines mandate that pyelonephritis must be ruled out in any young child with an unexplained fever, as delayed treatment can lead to permanent renal scarring. Since all three statements accurately describe the clinical reality of pediatric pyelonephritis, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Urine culture obtained via midstream catch (older children) or supra-pubic aspiration/catheterization (infants). * **Most Common Organism:** *E. coli* (80-90%). * **Imaging:** The first-line imaging is a **Renal Bladder Ultrasound (RBUS)**. A **Voiding Cystourethrogram (VCUG)** is indicated if the ultrasound is abnormal or if there is a recurrence of febrile UTI. * **Gold Standard for Scarring:** DMSA Scan (Dimercaptosuccinic acid) is the most sensitive test to detect acute pyelonephritis and late renal scarring.

Q: A 16-month-old child presents with excessive thirst and frequent, large voids of urine. Examination reveals dehydration, but no history of vomiting or diarrhea. What is the most likely cause?

Diabetes insipidus. **Explanation:** The clinical presentation of **excessive thirst (polydipsia)** and **frequent, large voids (polyuria)** in a child without gastrointestinal losses (vomiting/diarrhea) strongly suggests a disorder of water homeostasis. **Why Diabetes Insipidus (DI) is correct:** Diabetes Insipidus is characterized by either a deficiency of Antidiuretic Hormone (ADH) from the posterior pituitary (Central DI) or a lack of renal response to ADH (Nephrotic DI). This leads to an inability to concentrate urine, resulting in the excretion of large volumes of dilute urine. In infants and toddlers, this manifests as dehydration, irritability (relieved by drinking water), and polyuria. **Why the other options are incorrect:** * **Water Intoxication:** This occurs due to excessive intake of free water, leading to hyponatremia and fluid overload, not dehydration. * **Nephrotic Syndrome:** Typically presents with edema (due to hypoalbuminemia), proteinuria, and decreased urine output (oliguria), rather than polyuria and dehydration. * **Diabetes Mellitus (DM):** While DM causes polyuria (osmotic diuresis due to glycosuria) and polydipsia, it is usually associated with weight loss, polyphagia, and often ketoacidosis in children. DI is the more specific diagnosis for pure water loss leading to dehydration in this age group. **High-Yield Clinical Pearls for NEET-PG:** * **Water Deprivation Test:** The gold standard for diagnosing DI and differentiating it from primary polydipsia. * **Desmopressin (dDAVP) Challenge:** Used to differentiate Central DI (responds to dDAVP) from Nephrogenic DI (no response). * **Initial Sign in Infants:** Unexplained fever and "wet diapers" that are heavy but contain very pale, dilute urine. * **Biochemical Hallmark:** High serum osmolality (>300 mOsm/kg) with low urine osmolality (<300 mOsm/kg).

Q: A mother brought her 14-year-old boy with the complaint of cough with blood in sputum and red colored urine. On examination, his BP was 140/90 mmHg. Investigations showed his hemoglobin is 10 mg/dl and hematocrit is 31%. His urinalysis is suggestive of hematuria and proteinuria. Which of the following is the probable diagnosis?

Goodpasture syndrome. ### Explanation The clinical presentation of **hemoptysis** (cough with blood) and **hematuria** (red-colored urine) in a patient with hypertension and anemia points toward a **Pulmonary-Renal Syndrome**. **1. Why Goodpasture Syndrome is Correct:** Goodpasture syndrome is characterized by the presence of circulating **anti-glomerular basement membrane (anti-GBM) antibodies**. These antibodies attack the α3 chain of Type IV collagen found in both the alveolar basement membrane of the lungs and the glomerular basement membrane of the kidneys. This leads to: * **Diffuse Alveolar Hemorrhage:** Presenting as hemoptysis and iron-deficiency anemia (Hb 10 mg/dl). * **Rapidly Progressive Glomerulonephritis (RPGN):** Presenting as hematuria, proteinuria, and hypertension. **2. Why the Other Options are Incorrect:** * **Hemolytic-uremic syndrome (HUS):** Typically presents with a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury, usually following bloody diarrhea. It does not cause pulmonary hemorrhage. * **Poststreptococcal glomerulonephritis (PSGN):** A common cause of nephritic syndrome in children (hematuria, hypertension, edema) following a throat or skin infection. However, it does not involve the lungs or cause hemoptysis. * **Nephrotic syndrome:** Characterized by massive proteinuria (>3.5g/day), hypoalbuminemia, and generalized edema. Hemoptysis is not a feature, and hematuria is uncommon. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Confirmed by linear immunofluorescence (IF) showing IgG deposits along the GBM. * **Demographics:** Bimodal distribution (young males in their 20s and older females in their 60s). * **Treatment:** Plasmapheresis (to remove antibodies), corticosteroids, and cyclophosphamide. * **Differential for Pulmonary-Renal Syndrome:** Goodpasture syndrome, GPA (Wegener's), and SLE.

Q: Urinary ascites is due to which of the following?

All of the above. **Explanation:** Urinary ascites refers to the accumulation of urine within the peritoneal cavity. This occurs when there is a breach in the integrity of the urinary tract (extravasation) combined with a pressure gradient that forces urine into the abdomen. **Why "All of the Above" is Correct:** The underlying mechanism is the **leakage of urine** from any level of the urinary system into the retroperitoneal or intraperitoneal space. * **Injury to bladder during surgery (Option A):** Iatrogenic trauma (e.g., during pelvic or abdominal surgery) can cause a direct transmural tear in the bladder wall, leading to the intraperitoneal collection of urine. * **Ureteric obstruction (Option B):** Acute or chronic obstruction (e.g., by stones or tumors) increases intraluminal pressure. This can lead to a rupture of the renal pelvis or a "forniceal tear," causing urine to leak into the retroperitoneum and subsequently track into the peritoneal cavity. * **Congenital urethral atresia (Option C):** This is a classic cause in neonates. Severe distal obstruction (like Posterior Urethral Valves or Atresia) causes massive back-pressure, leading to transudation of urine across the thin bladder wall or rupture of the urinary tract. **Clinical Pearls for NEET-PG:** * **Most Common Cause in Neonates:** Posterior Urethral Valves (PUV) is the leading cause of spontaneous urinary ascites in newborns. * **Biochemical Hallmark:** The hallmark of urinary ascites is an **elevated Creatinine level in the ascitic fluid** compared to the serum Creatinine level (Fluid:Serum Creatinine ratio > 1). * **Metabolic Derangement:** Patients often present with "Pseudo-renal failure," characterized by hyponatremia, hyperkalemia, and elevated BUN/Creatinine due to the peritoneal reabsorption of urinary waste products. * **Diagnosis:** Voiding Cystourethrogram (VCUG) is the gold standard for identifying the site of leakage or obstruction in neonates.

Q: What is true about Nephrotic syndrome in a child?

Proteinuria of 4 gm/m2/hr is characteristic.. **Explanation:** Nephrotic Syndrome (NS) is defined by a triad of massive proteinuria, hypoalbuminemia ( 2 mg/mg. * **24-hour urine collection:** >40 mg/m²/hr. * **Dipstick:** 3+ or 4+. * *Note:* The option "4 gm/m²/hr" is a common typographical representation in exams for **40 mg/m²/hr** (or >3.5g/24hr in adults). In the context of competitive exams, this quantitative threshold is the physiological definition of the disease. **2. Analysis of Incorrect Options:** * **Option A:** While Minimal Change Disease (MCD) is indeed the most common cause of NS in children (approx. 80%), Option B is a more definitive physiological characteristic used to define the syndrome itself. (In many versions of this question, Option A is also considered true; however, if forced to choose the "most" characteristic feature, the protein threshold is the diagnostic gold standard). * **Option C:** The mainstay of therapy for the first episode of NS is **Corticosteroids (Prednisolone)**, not steroid-sparing agents like Cyclosporine or Azathioprine. * **Option D:** While Spontaneous Bacterial Peritonitis (SBP) is a known complication of NS (often due to *Streptococcus pneumoniae*), it is a **complication**, not a characteristic feature of the disease itself. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication:** Infections (due to loss of IgG and Complement factors in urine). * **Most common infection:** Peritonitis (Organism: *S. pneumoniae*). * **Hyperlipidemia:** Occurs due to increased hepatic synthesis of lipids in response to low oncotic pressure. * **Hypercoagulability:** Due to loss of Antithrombin III and increased levels of Factor VIII and fibrinogen.

Q: A child presents with a blood pressure of 190/110 mmHg, pedal edema ++, facial edema, and gross hematuria. Ascites is absent. What is the most likely diagnosis?

Acute Glomerulonephritis. ### Explanation The clinical presentation of **hypertension (190/110 mmHg)**, **gross hematuria**, and **edema** (facial and pedal) constitutes the classic **Nephritic Syndrome** triad. **1. Why Acute Glomerulonephritis (AGN) is correct:** AGN, most commonly Post-Streptococcal Glomerulonephritis (PSGN) in children, is characterized by an inflammatory process in the glomeruli. This leads to a decrease in Glomerular Filtration Rate (GFR), resulting in salt and water retention. The hallmark features are: * **Hematuria:** "Coke-colored" or smoky urine due to RBC leakage. * **Hypertension:** Significant elevation due to fluid overload and renin-angiotensin activation. * **Edema:** Typically periorbital/facial in the morning, becoming generalized. * **Absence of Ascites:** Edema in AGN is usually mild to moderate; massive edema/ascites is more characteristic of Nephrotic Syndrome. **2. Why the other options are incorrect:** * **Nephrotic Syndrome:** Characterized by massive proteinuria (>3.5g/day), hypoalbuminemia, and **generalized edema (Anasarca)** including ascites. Hypertension and gross hematuria are uncommon. * **Renal Thrombosis:** Usually presents in neonates with a palpable flank mass, thrombocytopenia, and hematuria, but not typically with this degree of systemic hypertension and facial edema. * **Renal Amyloidosis:** Rare in children; typically presents as chronic Nephrotic Syndrome rather than acute nephritic features. **3. NEET-PG High-Yield Pearls:** * **Most common cause of AGN in children:** PSGN (follows skin infection by 3–6 weeks or throat infection by 1–2 weeks). * **Best initial test:** Urinalysis (shows RBC casts and dysmorphic RBCs). * **Serology:** Low C3 levels are characteristic of PSGN (normalize within 6–8 weeks). * **Management:** Primarily supportive (fluid restriction, diuretics, and antihypertensives like Nifedipine).

Q: A 7-year-old boy presents with smoky-colored urine. His mother reports a sore throat several weeks prior that was untreated. Physical examination reveals hypertension and mild generalized edema. Urinalysis shows red blood cell casts. Which of the following accurately describes the likely causative microorganism?

Is sensitive to bacitracin. ### Explanation The clinical presentation of **smoky-colored urine** (hematuria), **hypertension**, **edema**, and **RBC casts** following a **sore throat** (pharyngitis) is classic for **Post-Streptococcal Acute Glomerulonephritis (PSAGN)**. This condition is a Type III hypersensitivity reaction caused by nephritogenic strains of **Group A Beta-Hemolytic Streptococcus (GABHS)**, specifically *Streptococcus pyogenes*. #### Why Option D is Correct: *Streptococcus pyogenes* (Group A Strep) is characterized by its sensitivity to the antibiotic **Bacitracin**. In a laboratory setting, a Bacitracin sensitivity test is a primary method used to differentiate GABHS from other beta-hemolytic streptococci (like Group B Strep, which is resistant). #### Why Other Options are Incorrect: * **Option A:** *S. pyogenes* causes **beta-hemolysis** (complete lysis of RBCs, creating a clear zone on blood agar), not alpha-hemolysis (partial green discoloration, typical of *S. pneumoniae* or *Viridans strep*). * **Option B:** All Streptococci are **catalase-negative**. This test distinguishes them from Staphylococci, which are catalase-positive. * **Option C:** **Coagulase-positive** is a specific characteristic of *Staphylococcus aureus*. Streptococci do not produce coagulase. #### NEET-PG High-Yield Pearls: * **Latent Period:** PSAGN occurs **1–3 weeks** after pharyngitis or **3–6 weeks** after skin infections (impetigo/pyoderma). * **Diagnosis:** Look for **low C3 levels** (C4 is usually normal) and elevated **ASO titers** (after pharyngitis) or **Anti-DNase B** (after skin infections). * **Histopathology:** Light microscopy shows a "starry sky" or "lumpy-bumpy" appearance; Electron microscopy shows **subepithelial humps**. * **Prognosis:** Excellent in children; most recover with supportive care (fluid restriction and diuretics).

Question 1

Which of the following nasal sprays is very effective in the control of enuresis?

Accepted Answer

Desmopressin

Answer

Pitressin

Answer

Lipressin

Answer

None of the above

Question 2

Which of the following is not true of acute Post-Streptococcal Glomerulonephritis (PSGN)?

Accepted Answer

PSGN following streptococcal skin infection will usually show positive Anti-Streptolysin O (ASLO) titre

Answer

Electron dense humps on glomerular basement membrane

Answer

Renal biopsy is indicated if prolonged hypocomplementemia persists beyond 2 months

Answer

C3 is low in the acute phase and returns to normal in 6-8 weeks

Question 3

Which of the following would be the plasma osmolality of a child with plasma Na+ 125 mEq/L, glucose of 108 mg/dL, and blood urea nitrogen (BUN) of 140 mg/dL?

Accepted Answer

306 mOsm/kg

Answer

360 mOsm/kg

Answer

312 mOsm/kg

Answer

318 mOsm/kg

Question 4

Which of the following is a true statement about pyelonephritis in children?

Accepted Answer

All of the above.

Answer

Neonates can present with non-specific symptoms.

Answer

Flank pain is a common finding.

Answer

Pyelonephritis should be suspected in all children less than 2 years of age with fever of unknown cause.

Question 5

A 16-month-old child presents with excessive thirst and frequent, large voids of urine. Examination reveals dehydration, but no history of vomiting or diarrhea. What is the most likely cause?

Accepted Answer

Diabetes insipidus

Answer

Water intoxication

Answer

Nephrotic syndrome

Answer

Diabetes mellitus

Question 6

A mother brought her 14-year-old boy with the complaint of cough with blood in sputum and red colored urine. On examination, his BP was 140/90 mmHg. Investigations showed his hemoglobin is 10 mg/dl and hematocrit is 31%. His urinalysis is suggestive of hematuria and proteinuria. Which of the following is the probable diagnosis?

Accepted Answer

Goodpasture syndrome

Answer

Hemolytic-uremic syndrome

Answer

Poststreptococcal glomerulonephritis

Answer

Nephrotic syndrome

Question 7

Urinary ascites is due to which of the following?

Accepted Answer

All of the above

Answer

Injury to bladder during surgery

Answer

Ureteric obstruction

Answer

Congenital urethral atresia

Question 8

What is true about Nephrotic syndrome in a child?

Accepted Answer

Proteinuria of 4 gm/m2/hr is characteristic.

Answer

Minimal change disease is the commonest cause.

Answer

Cyclosporine and Azathioprine are the mainstay of therapy.

Answer

Spontaneous bacterial peritonitis is associated with it.

Question 9

A child presents with a blood pressure of 190/110 mmHg, pedal edema ++, facial edema, and gross hematuria. Ascites is absent. What is the most likely diagnosis?

Accepted Answer

Acute Glomerulonephritis

Answer

Nephrotic Syndrome

Answer

Renal Thrombosis

Answer

Renal Amyloidosis

Question 10

A 7-year-old boy presents with smoky-colored urine. His mother reports a sore throat several weeks prior that was untreated. Physical examination reveals hypertension and mild generalized edema. Urinalysis shows red blood cell casts. Which of the following accurately describes the likely causative microorganism?

Accepted Answer

Is sensitive to bacitracin

Answer

Causes alpha-hemolysis on blood agar

Answer

Is catalase positive

Answer

Is coagulase positive

Nephrology — MCQs

Nephrology — MCQs

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