Nephrology Practice Questions

Q: What is the most common cause of persistent hypertension in a child with intrinsic renal disease?

Chronic pyelonephritis. **Explanation:** **Chronic pyelonephritis** (often associated with vesicoureteral reflux and renal scarring) is the most common cause of persistent hypertension in children with intrinsic renal disease. The underlying mechanism involves **segmental renal scarring**, which leads to localized ischemia. This ischemia triggers the **Renin-Angiotensin-Aldosterone System (RAAS)**, resulting in sustained elevation of blood pressure. In pediatric practice, any child with a history of recurrent urinary tract infections (UTIs) and hypertension must be evaluated for reflux nephropathy. **Analysis of Incorrect Options:** * **Chronic Glomerulonephritis (A):** While a common cause of acute hypertension (e.g., PSGN), it is less frequently the cause of *persistent* hypertension compared to the structural scarring seen in chronic pyelonephritis. * **Obstructive Uropathy (C):** This can lead to chronic kidney disease and hypertension, but it usually manifests as hypertension *after* significant renal parenchymal damage or secondary infection (pyelonephritis) has occurred. * **Renal Tumor (D):** While Wilms' tumor can cause hypertension due to renin production or renal artery compression, it is a rare cause compared to inflammatory/infectious parenchymal diseases. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of hypertension in children (overall):** Renal parenchymal disease (specifically chronic pyelonephritis/scarring). * **Most common cause of acute hypertension in children:** Acute Post-Streptococcal Glomerulonephritis (PSGN). * **Most common cause of renovascular hypertension in children:** Fibromuscular dysplasia (unlike atherosclerosis in adults). * **Gold standard for detecting renal scars:** DMSA Scan.

Q: All are features of Bartter syndrome EXCEPT?

Hypocalciuria. **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. It mimics the effect of **Loop diuretics (Furosemide)**. **Why Hypocalciuria is the correct answer:** In Bartter syndrome, the defect in the NKCC2 transporter (or related channels) leads to a loss of the positive transepithelial potential. This potential is normally the driving force for the paracellular reabsorption of Calcium and Magnesium. Consequently, patients experience **Hypercalciuria** (increased urinary calcium), which often leads to nephrocalcinosis. **Hypocalciuria** is actually a hallmark feature of **Gitelman syndrome** (which mimics Thiazide diuretics). **Analysis of incorrect options:** * **Hypokalemia:** Impaired sodium reabsorption in the TAL increases sodium delivery to the distal tubule. This stimulates aldosterone, which promotes potassium excretion in exchange for sodium, leading to profound hypokalemia. * **Metabolic Alkalosis:** Increased distal delivery of sodium and high aldosterone levels also promote hydrogen ion secretion, resulting in hypokalemic metabolic alkalosis. * **Salt Wasting:** Since the TAL is responsible for reabsorbing ~25% of filtered sodium, a defect here leads to significant urinary salt loss, polyuria, and secondary activation of the Renin-Angiotensin-Aldosterone System (RAAS). **NEET-PG High-Yield Pearls:** * **Bartter vs. Gitelman:** Bartter presents early (infancy/childhood) with polyhydramnios and hypercalciuria. Gitelman presents later (adolescence) with hypocalciuria and hypomagnesemia. * **Mnemonic:** **B**artter = **B**ig (Loop of Henle/Loop diuretics); **G**itelman = **G**ritty (Distal tubule/Thiazides). * **Clinical Sign:** Patients often have a "triangular face" and large ears.

Q: A 7-year-old girl presents with generalized body swelling. Urinalysis shows grade 3 proteinuria and the presence of hyaline and fatty casts. She has no history of hematuria. Which of the following statements about her condition is true?

No IgG deposits or C3 deposition on renal biopsy. The clinical presentation of generalized body swelling (edema) and heavy proteinuria (Grade 3) in a 7-year-old child, in the absence of hematuria, is the classic hallmark of **Minimal Change Disease (MCD)**. MCD is the most common cause of Nephrotic Syndrome in children (approx. 80% of cases). ### **Why Option A is Correct** In Minimal Change Disease, **Immunofluorescence (IF) microscopy** typically shows **no deposits** (negative for IgG, IgA, IgM, and C3). The primary pathology is seen only on Electron Microscopy, which reveals the **effacement (fusion) of podocyte foot processes**. Light microscopy usually appears normal, hence the name "Minimal Change." ### **Why Other Options are Incorrect** * **Option B (Low C3):** MCD is characterized by normal serum complement levels. Low C3 levels are seen in "nephritic" conditions like Post-Streptococcal Glomerulonephritis (PSGN), Membranoproliferative Glomerulonephritis (MPGN), or Systemic Lupus Erythematosus (SLE). * **Option C (IgA Nephropathy):** This typically presents as asymptomatic microscopic hematuria or gross hematuria following an upper respiratory tract infection (synpharyngitic hematuria), not pure nephrotic syndrome. * **Option D (Alport’s Syndrome):** This is a hereditary collagen disorder presenting with hematuria, progressive renal failure, sensorineural hearing loss, and ocular defects (lenticonus). ### **High-Yield NEET-PG Pearls** * **Most common cause of Nephrotic Syndrome in children:** Minimal Change Disease. * **Most common cause in adults:** Focal Segmental Glomerulosclerosis (FSGS) or Membranous Nephropathy. * **Hallmark finding:** Effacement of foot processes on Electron Microscopy. * **Treatment of choice:** Corticosteroids (Prednisolone). MCD is highly steroid-responsive. * **Selectivity:** Proteinuria in MCD is typically "highly selective" (mainly albumin).

Q: In children, what is the definition of acute kidney injury in terms of urine output?

Less than 0.5 ml/kg/hr for more than 6 hours. The definition of Acute Kidney Injury (AKI) in children is primarily based on the **pRIFLE** (Pediatric Risk, Injury, Failure, Loss, End-stage renal disease) and **KDIGO** criteria. Both classifications define the earliest stage of AKI (Stage 1 or "Risk") based on a reduction in urine output. ### Why Option B is Correct The standard pediatric threshold for AKI is a urine output of ** 1 ml/kg/hr) and serves as an early physiological marker of declining glomerular filtration before a significant rise in serum creatinine occurs. ### Analysis of Incorrect Options * **Option A ( 12 hours, or **Stage 3 (Failure)** if it persists for >24 hours. It is too stringent for the initial definition of AKI. * **Options C & D:** These values are too high. While a child producing 0.8 or 1 ml/kg/hr may be monitored, they do not meet the formal diagnostic criteria for AKI. ### High-Yield Clinical Pearls for NEET-PG * **Creatinine Criteria:** In children, AKI is also defined as an increase in serum creatinine to **≥1.5 times the baseline** or an absolute increase of **≥0.3 mg/dL** within 48 hours. * **pRIFLE vs. KDIGO:** While KDIGO is the global standard, **pRIFLE** is specifically validated for pediatrics and uses "estimated Creatinine Clearance (eCCl)" rather than absolute creatinine values. * **Normal Urine Output:** * Infants: 2 ml/kg/hr * Children: 1–1.5 ml/kg/hr * Adolescents: 0.5–1 ml/kg/hr

Q: In hemolytic uremic syndrome, which of the following is characteristic?

All of the above. **Hemolytic Uremic Syndrome (HUS)** is defined by a classic clinical triad: **Microangiopathic Hemolytic Anemia (MAHA), Thrombocytopenia, and Acute Kidney Injury (AKI).** It is most commonly seen in children following a prodrome of bloody diarrhea caused by Shiga toxin-producing *E. coli* (STEC), specifically serotype O157:H7. ### **Explanation of Options:** * **Microangiopathic Hemolytic Anemia (MAHA):** This is a hallmark of HUS. Endothelial injury leads to the formation of microthrombi in small vessels. As RBCs pass through these partially occluded vessels, they are mechanically shredded, resulting in **schistocytes** (fragmented cells) on a peripheral smear and a negative Coombs test. * **Thrombocytopenia and Renal Failure:** Platelets are consumed during the formation of microthrombi, leading to low platelet counts (usually <150,000/mm³). The renal microvasculature is particularly susceptible, leading to decreased GFR, oliguria, and hematuria. * **Normal Coagulative Profile:** This is a **critical diagnostic differentiator.** Unlike Disseminated Intravascular Coagulation (DIC), the coagulation cascade is not activated in HUS. Therefore, PT, aPTT, and Fibrinogen levels remain **normal**. ### **NEET-PG High-Yield Pearls:** * **Most common cause of AKI in children:** HUS. * **Pathogenesis:** Shiga toxin causes direct endothelial damage, primarily in the glomerulus. * **Atypical HUS:** Caused by uncontrolled activation of the alternative complement pathway (Factor H deficiency); treated with **Eculizumab**. * **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.

Question 1

All are features of Alport syndrome, except?

Accepted Answer

Hypertelorism

Answer

Hematuria

Answer

Sensorineural hearing loss

Answer

Lenticonus

Question 2

What is the most common cause of persistent hypertension in a child with intrinsic renal disease?

Accepted Answer

Chronic pyelonephritis

Answer

Chronic glomerulonephritis

Answer

Obstructive uropathy

Answer

Renal tumor

Question 3

All are features of Bartter syndrome EXCEPT?

Accepted Answer

Hypocalciuria

Answer

Hypokalemia

Answer

Metabolic alkalosis

Answer

Salt wasting

Question 4

An 11-year-old child presents with failure to thrive and metabolic acidosis with an increased anion gap. Which of the following is NOT a likely diagnosis in the differential diagnosis?

Accepted Answer

Renal tubular acidosis

Answer

Insulin dependent diabetes mellitus

Answer

Chronic renal failure

Answer

Inborn errors of metabolism

Question 5

Which of the following is NOT a clinical feature of minimal change glomerulonephritis?

Accepted Answer

Hypertension

Answer

Edema

Answer

Selective proteinuria

Answer

Fever

Question 6

A 7-year-old girl presents with generalized body swelling. Urinalysis shows grade 3 proteinuria and the presence of hyaline and fatty casts. She has no history of hematuria. Which of the following statements about her condition is true?

Accepted Answer

No IgG deposits or C3 deposition on renal biopsy

Answer

C3 level will be low

Answer

IgA nephropathy is the likely diagnosis

Answer

Alport's syndrome is the likely diagnosis

Question 7

A 4-year-old boy develops a large erythematous rash around the site of a mosquito bite. One month later, he is taken to a pediatrician due to a puffy face and swollen ankles. The scanty urine sample has a reddish-brown hue and contains both red blood cells and protein. Which of the following distinctive features would be most likely to be seen on renal biopsy?

Accepted Answer

Subepithelial electron dense humps

Answer

Fusion of podocyte foot processes

Answer

IgA in the mesangium

Answer

Linear IgG deposits

Question 8

In children, what is the definition of acute kidney injury in terms of urine output?

Accepted Answer

Less than 0.5 ml/kg/hr for more than 6 hours

Answer

Less than 0.3 ml/kg/hr for more than 6 hours

Answer

Less than 0.8 ml/kg/hr for more than 6 hours

Answer

Less than 1 ml/kg/hr for more than 6 hours

Question 9

In hemolytic uremic syndrome, which of the following is characteristic?

Accepted Answer

All of the above

Answer

Thrombocytopenia and renal failure

Answer

Normal coagulative profile

Answer

Microangiopathic hemolytic anemia

Question 10

A 9-year-old boy presents with decreased urine output, cola-colored urine, and swelling of the face and hands for 2 days. He is hypertensive, has a puffy face, and pitting edema of the lower limbs. Four weeks prior, he had skin lesions. A diagnosis of post-streptococcal glomerulonephritis is made. If an antibiotic is to be used to limit the spread of nephritogenic organisms, what is the drug of choice?

Accepted Answer

Penicillin

Answer

Cefixime

Answer

Meropenem

Answer

Amoxycillin

Nephrology — MCQs

Nephrology — MCQs

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