What is the most common cause of urinary tract infection in children?
Q2Medium
A 10-year-old boy presents with hypertension. There is no other significant history. What is the most likely cause of his hypertension?
Q3Medium
A patient with congenital nephrotic syndrome requires which of the following procedures?
Q4Medium
An 8-year-old child has had abdominal pain and dark urine for 10 days. Physical examination shows blotchy purple skin lesions on the trunk and extremities. Urinalysis shows hematuria and proteinuria. Serologic test results are negative for myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) and proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA). A skin biopsy specimen shows necrotizing vasculitis of small dermal vessels. A renal biopsy specimen shows immune complex deposition in glomeruli, with some IgA-rich immune complexes. Which of the following is the most likely diagnosis?
Q5Medium
After her first urinary tract infection (UTI), a 1-year-old girl has a voiding cystourethrogram with findings shown below. Which of the following is the most appropriate management option?
Nephrology Indian Medical PG Practice Questions and MCQs
Question 1: What is the most common cause of urinary tract infection in children?
A. Escherichia coli (Correct Answer)
B. Klebsiella species
C. Pseudomonas aeruginosa
D. Candida
Explanation: **Explanation:**
**Escherichia coli (Option A)** is the most common cause of urinary tract infection (UTI) in children, accounting for approximately **80–90% of all cases**. The primary mechanism is the ascending route, where fecal flora colonize the perineum and enter the bladder. *E. coli* possesses specific virulence factors, such as **P-fimbriae (pyelonephritis-associated pili)**, which allow the bacteria to adhere to the uroepithelial cells and resist being washed away by urine flow.
**Why other options are incorrect:**
* **Klebsiella species (Option B):** While it is the second most common Gram-negative cause, it typically occurs in children with recurrent UTIs, those who have received prior antibiotics, or those with structural abnormalities.
* **Pseudomonas aeruginosa (Option C):** This is an opportunistic pathogen. It is rarely a cause in healthy children and is usually associated with hospital-acquired infections, urinary tract instrumentation (catheterization), or chronic structural malformations.
* **Candida (Option D):** Fungal UTIs are uncommon in immunocompetent children. They are typically seen in neonates in the NICU, children on prolonged broad-spectrum antibiotics, or those with indwelling catheters.
**High-Yield Clinical Pearls for NEET-PG:**
* **Most common route of infection:** Ascending route (except in neonates, where hematogenous spread is more common).
* **Most common viral cause:** Adenovirus (typically causes acute hemorrhagic cystitis).
* **Gold Standard Diagnosis:** Urine culture obtained via suprapubic aspiration (any growth is significant) or transurethral catheterization (>50,000 CFU/mL).
* **Proteus mirabilis:** Often associated with UTIs in uncircumcised males and is linked to the formation of struvite (staghorn) calculi due to its urease-producing nature.
Question 2: A 10-year-old boy presents with hypertension. There is no other significant history. What is the most likely cause of his hypertension?
A. Chronic glomerulonephritis
B. Polycystic kidney disease (Correct Answer)
C. Reflux nephropathy
D. Renal parenchymal disease
Explanation: **Explanation:**
In the pediatric population, hypertension is most commonly **secondary** to an underlying condition, with renal causes accounting for over 80% of cases.
**Why Polycystic Kidney Disease (PKD) is the correct answer:**
While "Renal Parenchymal Disease" is a broad category, **Autosomal Dominant Polycystic Kidney Disease (ADPKD)** is a specific and frequent cause of asymptomatic hypertension in older children (around age 10). Hypertension in PKD often precedes a significant decline in glomerular filtration rate (GFR) due to the activation of the Renin-Angiotensin-Aldosterone System (RAAS) caused by cyst expansion and local renal ischemia. In the context of a child presenting with *isolated* hypertension and no other history (like hematuria or edema), PKD is a high-yield diagnosis.
**Analysis of Incorrect Options:**
* **Chronic Glomerulonephritis:** Usually presents with a history of hematuria, proteinuria, or previous episodes of acute nephritic syndrome.
* **Reflux Nephropathy:** Typically associated with a history of recurrent Urinary Tract Infections (UTIs) or voiding dysfunction, which is absent in this clinical vignette.
* **Renal Parenchymal Disease:** This is a general umbrella term that includes glomerulonephritis, pyelonephritis, and PKD. In competitive exams like NEET-PG, when a specific disease entity (PKD) is provided alongside a general category, the specific diagnosis is preferred if it fits the clinical profile.
**NEET-PG High-Yield Pearls:**
* **Most common cause of HTN in children:** Renal Parenchymal Disease (overall).
* **Most common cause of HTN in newborns:** Renal Artery Thrombosis (often due to umbilical artery catheterization).
* **Gold Standard for diagnosis:** 24-hour Ambulatory Blood Pressure Monitoring (ABPM).
* **First-line investigation:** Renal Ultrasound (to look for scars, cysts, or size discrepancies).
Question 3: A patient with congenital nephrotic syndrome requires which of the following procedures?
A. Live attenuated vaccines
B. Renal biopsy (Correct Answer)
C. High-dose steroids
D. Low-protein diet
Explanation: **Explanation:**
**Congenital Nephrotic Syndrome (CNS)** is defined as the onset of nephrotic-range proteinuria, edema, and hypoalbuminemia within the first three months of life.
**Why Renal Biopsy is the Correct Answer:**
In CNS, a renal biopsy is a critical diagnostic step to differentiate between various underlying etiologies. While the most common cause is the **Finnish type (NPHS1 mutation)**, a biopsy helps rule out other structural or syndromic causes like Diffuse Mesangial Sclerosis (DMS) or secondary causes like congenital syphilis or CMV. Histopathology in the Finnish type typically shows characteristic microcystic dilatation of the proximal tubules.
**Analysis of Incorrect Options:**
* **Live Attenuated Vaccines:** These are generally **contraindicated** in patients with nephrotic syndrome who are on immunosuppressive therapy or are severely edematous/malnourished due to the risk of disseminated infection.
* **High-dose Steroids:** Unlike Minimal Change Disease (MCD) in older children, CNS is **steroid-resistant**. The condition is caused by genetic mutations in podocyte proteins (e.g., Nephrin, Podocin), making steroid therapy ineffective and potentially toxic.
* **Low-protein Diet:** Patients with CNS lose massive amounts of albumin in the urine. A low-protein diet would worsen the malnutrition and growth failure. Instead, these infants require a **high-protein, high-calorie diet** to compensate for urinary losses.
**High-Yield Clinical Pearls for NEET-PG:**
* **Finnish Type (NPHS1):** Most common cause; inherited as autosomal recessive; mutation in the **Nephrin** gene (chromosome 19q13).
* **Antenatal Diagnosis:** Elevated **Alpha-fetoprotein (AFP)** levels in amniotic fluid or maternal serum.
* **Management:** Definitive treatment is **bilateral nephrectomy** (to stop protein loss) followed by peritoneal dialysis and eventual **renal transplantation**.
Question 4: An 8-year-old child has had abdominal pain and dark urine for 10 days. Physical examination shows blotchy purple skin lesions on the trunk and extremities. Urinalysis shows hematuria and proteinuria. Serologic test results are negative for myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) and proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA). A skin biopsy specimen shows necrotizing vasculitis of small dermal vessels. A renal biopsy specimen shows immune complex deposition in glomeruli, with some IgA-rich immune complexes. Which of the following is the most likely diagnosis?
A. Giant cell arteritis
B. Henoch-Schonlein purpura (Correct Answer)
C. Polyarteritis nodosa
D. Takayasu arteritis
Explanation: **Explanation:**
The clinical presentation of **abdominal pain, dark urine (hematuria), and palpable purpura** (blotchy purple lesions) in a child is the classic triad of **Henoch-Schönlein Purpura (HSP)**, now commonly referred to as **IgA Vasculitis**.
**Why Option B is Correct:**
HSP is a small-vessel vasculitis characterized by the deposition of **IgA-dominant immune complexes**. The skin biopsy showing necrotizing vasculitis of small dermal vessels (leukocytoclastic vasculitis) and the renal biopsy showing IgA-rich deposits in the mesangium are pathognomonic. The negative ANCA results help rule out ANCA-associated vasculitides like Granulomatosis with polyangiitis.
**Why Other Options are Incorrect:**
* **A & D (Giant cell & Takayasu arteritis):** These are **large-vessel vasculitides**. They typically present with absent pulses, bruits, or temporal headaches and do not feature IgA-mediated glomerulonephritis or small-vessel dermal vasculitis.
* **C (Polyarteritis nodosa):** This is a **medium-vessel vasculitis**. While it can cause abdominal pain (mesenteric ischemia) and renal involvement, it typically spares the capillaries (glomeruli) and is not associated with IgA deposition.
**High-Yield Clinical Pearls for NEET-PG:**
* **Most common** systemic vasculitis in children.
* **Classic Tetrad:** Palpable purpura (without thrombocytopenia), arthralgia, abdominal pain, and renal disease.
* **Triggers:** Often follows an Upper Respiratory Tract Infection (URTI).
* **Renal Pathology:** Identical to **IgA Nephropathy (Berger’s disease)**; however, HSP is a systemic multisystem involvement, whereas Berger’s is localized to the kidney.
* **Treatment:** Usually supportive; steroids are used for severe gastrointestinal or renal involvement.
Question 5: After her first urinary tract infection (UTI), a 1-year-old girl has a voiding cystourethrogram with findings shown below. Which of the following is the most appropriate management option?
A. Low-dose daily antibiotics (Correct Answer)
B. Immediate surgical reimplantation of the ureters
C. Weekly urinalyses and culture
D. Diet low in protein
Explanation: ***Low-dose daily antibiotics***
- **Prophylactic antibiotics** are the first-line conservative management for **Grade II-III vesicoureteral reflux (VUR)** in young children to prevent recurrent UTIs and potential **renal scarring**.
- This approach allows time for potential **spontaneous resolution** of VUR as the child grows, which commonly occurs in low-to-moderate grade reflux.
*Immediate surgical reimplantation of the ureters*
- **Ureteral reimplantation** is reserved for **high-grade VUR (Grade IV-V)** or cases with breakthrough infections despite prophylactic antibiotics.
- **Grade II-III VUR** often resolves spontaneously with conservative management, making immediate surgery unnecessarily aggressive.
*Weekly urinalyses and culture*
- **Monitoring alone** without prophylaxis increases the risk of **recurrent UTIs** and potential **renal scarring** in a child with established VUR.
- This approach fails to provide **active protection** against ascending infections that VUR predisposes the patient to.
*Diet low in protein*
- **Protein restriction** is indicated for **chronic kidney disease** with significant **renal impairment**, not for VUR management.
- VUR with normal renal function does not require **dietary modifications**, and protein is essential for normal growth in children.
