Nephrology Practice Questions

Q: Lowe's syndrome is characterized by the following, except:

Undescended testes. **Lowe’s Syndrome**, also known as **Oculocerebrorenal Syndrome**, is a rare X-linked recessive disorder caused by a mutation in the *OCRL1* gene. This gene encodes a phosphatase enzyme found in the Golgi apparatus, and its deficiency leads to multisystemic dysfunction primarily affecting the eyes, brain, and kidneys. ### **Explanation of Options** * **Correct Answer (B) Undescended testes:** This is the correct choice because cryptorchidism (undescended testes) is **not** a characteristic feature of Lowe’s syndrome. While the syndrome involves multiple systems, the reproductive system is typically not affected in this specific manner. * **Option (A) Hypophosphatemic rickets:** Lowe’s syndrome causes **proximal renal tubular acidosis (Fanconi Syndrome)**. The resulting renal phosphate wasting leads to hypophosphatemia, which manifests clinically as rickets in children. * **Option (C) Defect in the CNS and eyes:** This is a hallmark of the disease. Ocular findings include **bilateral congenital cataracts** (present in 100% of cases) and glaucoma. CNS involvement presents as profound hypotonia ("floppy baby"), intellectual disability, and behavioral issues. * **Option (D) Aminoaciduria:** As part of the generalized **Fanconi Syndrome**, the proximal tubule fails to reabsorb solutes, leading to aminoaciduria, glucosuria, and low-molecular-weight proteinuria. ### **High-Yield Clinical Pearls for NEET-PG** * **Inheritance:** X-linked Recessive (primarily affects males). * **The "Triad":** Congenital cataracts, Neonatal hypotonia, and Renal Fanconi syndrome. * **Biochemical Marker:** Elevated levels of lysosomal enzymes in the serum and metabolic acidosis with a normal anion gap. * **Diagnosis:** Confirmed by measuring **inositol polyphosphate 5-phosphatase** activity in skin fibroblasts or through *OCRL* gene sequencing.

Q: A child presents with recurrent muscle cramps and spasms. Laboratory analysis reveals hypokalemia, metabolic alkalosis, hypocalciuria, and increased urinary magnesium. What is the most probable diagnosis?

Gittelman syndrome. **Explanation:** The clinical presentation of **Gittelman syndrome** is characterized by the triad of hypokalemic metabolic alkalosis, **hypocalciuria**, and **hypomagnesemia** (due to renal magnesium wasting). It is an autosomal recessive disorder caused by a mutation in the **SLC12A3 gene**, leading to a defect in the **Thiazide-sensitive Sodium-Chloride (NaCl) cotransporter** in the Distal Convoluted Tubule (DCT). This mimics the chronic use of Thiazide diuretics. **Why the other options are incorrect:** * **Bartter Syndrome:** While it also presents with hypokalemic metabolic alkalosis, it is characterized by **hypercalciuria** (increased urinary calcium) and often presents earlier in infancy with polyuria and growth retardation. It mimics the effect of **Loop diuretics** (defect in the NKCC2 transporter in the Thick Ascending Limb). * **Liddle Syndrome:** This is a "pseudo-aldosteronism" caused by overactivity of ENaC channels. While it causes hypokalemia and metabolic alkalosis, it is distinguished by **hypertension** and low renin/aldosterone levels. Gittelman patients are typically normotensive or hypotensive. **High-Yield NEET-PG Pearls:** * **Gittelman vs. Bartter:** The "Gold Standard" differentiator is urinary calcium. **Gittelman = Low Calcium**; **Bartter = High Calcium.** * **Mnemonic:** **G**ittelman is like **G**entle (presents later in childhood/adolescence) and associated with low **M**agnesium (**M**agnesium starts with 'M', the next letter after 'L' in Gitte**l**man). * **Metabolic Profile:** Both Bartter and Gittelman present with **increased Renin and Aldosterone** (Secondary Hyperaldosteronism) due to volume depletion.

Q: What is the best initial treatment for enuresis?

Bed alarm. **Explanation:** Monosymptomatic nocturnal enuresis (bedwetting in children >5 years without daytime symptoms) is primarily managed through behavioral interventions and conditioning. **Why Bed Alarm is Correct:** The **bedwetting alarm** is considered the **most effective long-term treatment** and the best initial active intervention. It works on the principle of **classical conditioning**: a sensor detects moisture and triggers an alarm, waking the child to void in the toilet. Over time, the child learns to associate bladder fullness with waking up. It has a higher long-term cure rate and lower relapse rate compared to pharmacological options. **Why Incorrect Options are Wrong:** * **Oxybutynin (A):** This is an anticholinergic used for "non-monosymptomatic" enuresis (children with daytime urgency or overactive bladder). It is not the first-line for isolated nocturnal bedwetting. * **Desmopressin (B):** An ADH analogue that reduces urine production. While it provides rapid symptomatic relief (useful for sleepovers), it has a **high relapse rate** once discontinued and is generally considered second-line or used as an adjunct to alarms. * **Imipramine (D):** A tricyclic antidepressant once commonly used, it is now rarely recommended due to its narrow therapeutic index and the risk of **cardiotoxicity/fatal arrhythmia** in overdose. **Clinical Pearls for NEET-PG:** 1. **Initial Step:** Always start with **behavioral advice** (limiting evening fluids, scheduled voiding) and reassurance. If these fail, the **bed alarm** is the next best step. 2. **Age Criteria:** Enuresis is only diagnosed if the child is **≥5 years** of age. 3. **Success Metric:** Alarm therapy usually requires 3–4 months of consistent use to be effective. 4. **Rule Out:** Before starting treatment, always rule out secondary causes like UTI, Diabetes Mellitus, or Constipation.

Q: What is the drug of choice for nocturnal enuresis in children?

Desmopressin. **Explanation:** **Nocturnal Enuresis** (bedwetting) is defined as involuntary voiding of urine during sleep in children aged ≥5 years. **Why Desmopressin is the Correct Answer:** Desmopressin (DDAVP), a synthetic analogue of Antidiuretic Hormone (ADH), is the **first-line pharmacological treatment**. It works by binding to V2 receptors in the renal collecting ducts, increasing water reabsorption and reducing urine volume produced overnight. It is preferred due to its rapid onset of action and superior safety profile compared to older alternatives. **Analysis of Incorrect Options:** * **Imipramine & Amitriptyline:** These are Tricyclic Antidepressants (TCAs). While effective in increasing bladder capacity and anticholinergic action, they are **second or third-line** due to the risk of cardiotoxicity (arrhythmias) and potential lethality in accidental overdose. * **Benzodiazepines:** These have no role in the management of enuresis; they may actually worsen the condition by deepening sleep and causing muscle relaxation. **High-Yield Clinical Pearls for NEET-PG:** * **Initial Management:** The first step is always **behavioral modification** (fluid restriction before bed, bladder training) and **Enuresis Alarms** (most effective long-term therapy with the lowest relapse rate). * **Drug of Choice:** Desmopressin is the drug of choice when alarms fail or for short-term relief (e.g., sleepovers). * **Caution:** When using Desmopressin, fluid intake must be restricted 1 hour before and 8 hours after administration to prevent **hyponatremia** and water intoxication. * **Rule Out:** Always exclude secondary causes like UTI, Diabetes Mellitus, or Constipation before diagnosing primary enuresis.

Q: What is the treatment of choice for nocturnal enuresis?

Behavioral therapy. **Explanation:** Nocturnal enuresis (bedwetting) is defined as involuntary voiding of urine during sleep in children aged ≥5 years. The management follows a stepped approach, prioritizing non-pharmacological interventions. **Why Behavioral Therapy is the Correct Answer:** Behavioral therapy is the **first-line treatment of choice**. It begins with **lifestyle modifications** (limiting evening fluid intake, scheduled voiding before bed) and **positive reinforcement** (star charts). If these fail, the **enuresis alarm** (conditioning therapy) is considered the most effective long-term treatment with the lowest relapse rates. It works by conditioning the child to wake up when the bladder is full. **Analysis of Incorrect Options:** * **Oxybutynin (A):** An anticholinergic used primarily for "overactive bladder" or daytime urgency. It is not first-line for isolated nocturnal enuresis. * **Imipramine (B):** A tricyclic antidepressant once commonly used; however, it is now a **last-resort** due to its narrow therapeutic index and risk of fatal cardiac arrhythmias in overdose. * **Desmopressin (C):** An ADH analogue that reduces urine production. While it provides rapid symptomatic relief (useful for sleepovers), it has a **high relapse rate** once discontinued and is generally reserved for cases resistant to behavioral therapy. **NEET-PG High-Yield Pearls:** * **Definition Age:** Must be at least 5 years old (developmental age). * **Most Common Cause:** Maturation delay of sleep-wake mechanisms. * **First-line:** Behavioral/Lifestyle changes → Enuresis Alarm. * **Best Pharmacotherapy:** Desmopressin (oral melt formulation preferred). * **Rule Out:** Always screen for constipation, UTI, or Diabetes Mellitus if enuresis is secondary (started after a 6-month dry period).

Q: During the physical examination of a newborn boy, the pediatrician notices that the urethral meatus is positioned on the lower side of the penile shaft. What is the appropriate diagnosis for this congenital birth defect?

Hypospadias. ### Explanation **Correct Answer: C. Hypospadias** **Understanding the Concept:** Hypospadias is a common congenital anomaly where the **urethral meatus** is located on the **ventral (underside)** aspect of the penis, rather than at the tip of the glans. It results from the failure of the urethral folds to fuse completely during the 8th to 14th weeks of gestation. It is frequently associated with **chordee** (ventral curvature of the penis) and a "hooded" prepuce (incomplete foreskin). **Analysis of Incorrect Options:** * **A. Epispadias:** This is a rarer condition where the urethral opening is on the **dorsal (upper)** surface of the penis. It is often associated with bladder exstrophy. * **B. Hydroureter:** This refers to the dilation of the ureter, usually due to an obstruction or vesicoureteral reflux (VUR). It is an internal anatomical finding, not a visible external urethral defect. * **D. Peyronie disease:** This is an **acquired** condition in adults characterized by fibrous plaque formation in the tunica albuginea, leading to painful erections and penile curvature. It is not a congenital urethral malformation. **High-Yield Clinical Pearls for NEET-PG:** * **Management Rule:** **Circumcision is strictly contraindicated** in newborns with hypospadias because the preputial skin is required for future surgical reconstruction (urethroplasty). * **Timing of Surgery:** Ideally performed between **6 to 12 months** of age. * **Associated Findings:** Always check for **undescended testes** (cryptorchidism) and inguinal hernias. If hypospadias is severe (proximal) and associated with undescended testes, consider an evaluation for **Disorders of Sex Development (DSD)**. * **Location:** Can be glandular (most common), coronal, penile, or scrotal.

Q: An 8-year-old boy presents with a history of diarrhea followed by decreased urine output. Blood examination shows 90,000 thrombocytes/cm³. What is the most likely diagnosis?

Hemolytic Uremic Syndrome. ### Explanation The clinical presentation of an 8-year-old boy with a prodrome of **diarrhea**, followed by **decreased urine output** (acute kidney injury) and **thrombocytopenia** (90,000/cm³), is the classic triad of **Hemolytic Uremic Syndrome (HUS)**. #### Why Option A is Correct: HUS is the most common cause of acute renal failure in children. It typically follows an infection with Shiga toxin-producing *E. coli* (STEC), most commonly serotype **O157:H7**. The toxin causes endothelial damage, leading to microangiopathic hemolytic anemia (MAHA), thrombocytopenia (due to platelet consumption), and renal microthrombi resulting in oliguria. #### Why Other Options are Incorrect: * **B. Disseminated Intravascular Coagulation (DIC):** While DIC also presents with thrombocytopenia and renal failure, it is characterized by abnormal coagulation profiles (prolonged PT/aPTT and low fibrinogen). In HUS, the coagulation profile is typically **normal**. * **C. Hemophilia:** This is an X-linked recessive disorder causing factor VIII or IX deficiency. It presents with deep tissue bleeds or hemarthrosis, not diarrhea-associated renal failure or thrombocytopenia. * **D. Idiopathic Thrombocytopenic Purpura (ITP):** ITP presents with isolated thrombocytopenia, usually following a viral respiratory infection. It does not cause renal failure or follow a diarrheal prodrome. #### High-Yield Clinical Pearls for NEET-PG: * **The HUS Triad:** 1. Microangiopathic Hemolytic Anemia (Schistocytes on smear), 2. Thrombocytopenia, 3. Acute Kidney Injury. * **Management:** Primarily supportive (fluid/electrolyte balance, dialysis). **Antibiotics and anti-motility agents are contraindicated** as they may increase toxin release and worsen the condition. * **Atypical HUS:** Caused by uncontrolled complement activation (Factor H deficiency); it does not require a diarrheal prodrome.

Q: An infant with a history of diarrhea 5 days back presents with urea of 200 mg% and creatinine of 5 mg/dL. The platelet count is 90,000/mm 3. Fragmented RBCs are found in the peripheral smear. What is the most likely diagnosis?

Hemolytic Uremic Syndrome (HUS). ### Explanation The clinical presentation describes the classic **triad of Hemolytic Uremic Syndrome (HUS)**: 1. **Microangiopathic Hemolytic Anemia (MAHA):** Evidence of fragmented RBCs (schistocytes) on peripheral smear. 2. **Thrombocytopenia:** Platelet count <150,000/mm³ (90,000 in this case). 3. **Acute Kidney Injury (AKI):** Significantly elevated Urea (200 mg%) and Creatinine (5 mg/dL). The history of **diarrhea** 5 days prior strongly suggests **Typical HUS**, usually caused by Shiga toxin-producing *E. coli* (STEC, O157:H7). The toxin damages glomerular endothelial cells, leading to microthrombi formation, which consumes platelets and mechanically shears RBCs. #### Why the other options are incorrect: * **Thrombotic Thrombocytopenic Purpura (TTP):** While it shares the MAHA and thrombocytopenia features, TTP is rare in infants and typically presents with a **pentad** including prominent neurological symptoms and fever. It is caused by ADAMTS13 deficiency. * **Idiopathic Thrombocytopenic Purpura (ITP):** ITP presents with isolated thrombocytopenia. It does **not** cause fragmented RBCs (hemolysis) or renal failure. * **Hemolytic Anemia:** This is a broad term. While hemolysis is present here, it does not account for the concurrent thrombocytopenia and acute renal failure. #### NEET-PG High-Yield Pearls: * **Most common cause of AKI in children:** HUS. * **Typical HUS:** Preceded by bloody diarrhea (*E. coli* O157:H7); prognosis is generally good with supportive care. * **Atypical HUS:** Due to alternative complement pathway dysregulation; carries a poorer prognosis and requires Eculizumab. * **Management:** Primarily supportive (fluids, dialysis). **Antibiotics and anti-motility agents are contraindicated** in STEC-HUS as they may increase toxin release.

Question 1

Lowe's syndrome is characterized by the following, except:

Accepted Answer

Undescended testes

Answer

Hypophosphatemic rickets

Answer

Defect in the CNS and eyes

Answer

Aminoaciduria

Question 2

A child presents with recurrent muscle cramps and spasms. Laboratory analysis reveals hypokalemia, metabolic alkalosis, hypocalciuria, and increased urinary magnesium. What is the most probable diagnosis?

Accepted Answer

Gittelman syndrome

Answer

Bartter syndrome

Answer

Liddle syndrome

Answer

None of the above

Question 3

Which one of the following statements is false with regard to pyuria in children?

Accepted Answer

Presence of more than 5 white blood cells/high power field for girls and more than 3 white blood cells/high power field for boys

Answer

Infection can occur without pyuria

Answer

Pyuria may be present without urinary tract infection

Answer

Isolated pyuria is neither confirmatory nor diagnostic for urinary tract infection

Question 4

What is the best initial treatment for enuresis?

Accepted Answer

Bed alarm

Answer

Oxybutinin

Answer

Desmopressin

Answer

Imipramine

Question 5

What is the drug of choice for nocturnal enuresis in children?

Accepted Answer

Desmopressin

Answer

Imipramine

Answer

Amitriptyline

Answer

Benzodiazepines

Question 6

What is the treatment of choice for nocturnal enuresis?

Accepted Answer

Behavioral therapy

Answer

Oxybutynin

Answer

Imipramine

Answer

Desmopressin

Question 7

What is the most common cause of urinary ascites?

Accepted Answer

Posterior urethral valve

Answer

Bilateral pelviureteric junction obstruction

Answer

Meatal stenosis

Answer

Infantile polycystic kidney disease

Question 8

During the physical examination of a newborn boy, the pediatrician notices that the urethral meatus is positioned on the lower side of the penile shaft. What is the appropriate diagnosis for this congenital birth defect?

Accepted Answer

Hypospadias

Answer

Epispadias

Answer

Hydroureter

Answer

Peyronie disease

Question 9

An 8-year-old boy presents with a history of diarrhea followed by decreased urine output. Blood examination shows 90,000 thrombocytes/cm³. What is the most likely diagnosis?

Accepted Answer

Hemolytic Uremic Syndrome

Answer

Disseminated Intravascular Coagulation

Answer

Hemophilia

Answer

Idiopathic Thrombocytopenic Purpura

Question 10

An infant with a history of diarrhea 5 days back presents with urea of 200 mg% and creatinine of 5 mg/dL. The platelet count is 90,000/mm
3. Fragmented RBCs are found in the peripheral smear. What is the most likely diagnosis?

Accepted Answer

Hemolytic Uremic Syndrome (HUS)

Answer

Thrombotic Thrombocytopenic Purpura (TTP)

Answer

Idiopathic Thrombocytopenic Purpura (ITP)

Answer

Hemolytic Anemia

Nephrology — MCQs

Nephrology — MCQs

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