Nephrology Practice Questions

Q: In Bartter syndrome defect is seen in:

Defect in thick ascending limb of loop of Henle. ***Defect in thick ascending limb of loop of Henle*** - Bartter syndrome results from a **genetic defect** affecting the activity of the **Na-K-2Cl cotransporter (NKCC2)** in the thick ascending limb of the loop of Henle. - This defect impairs **sodium, potassium, and chloride reabsorption**, leading to their increased excretion and characteristic electrolyte imbalances. *Defect in proximal convoluted tubule (PCT)* - Defects in the **proximal convoluted tubule** are typically associated with conditions like **Fanconi syndrome**, affecting reabsorption of glucose, amino acids, phosphate, and bicarbonate [1]. - This does not align with the characteristic **electrolyte imbalances** seen in Bartter syndrome, particularly hypokalemia and metabolic alkalosis. *Defect in distal convoluted tubule (DCT)* - Defects in the **distal convoluted tubule** are seen in conditions like **Gitelman syndrome**, which affects the Na-Cl cotransporter. - While both Bartter and Gitelman syndromes present with hypokalemia and metabolic alkalosis, the specific transporter affected and the severity of certain electrolyte disturbances differ. *No defect* - Bartter syndrome is a well-defined **genetic disorder** characterized by specific renal tubular defects. - Stating there is no defect is incorrect, as the syndrome arises directly from impaired renal tubule function.

Q: Which of the following is a cause of hypokalemic metabolic alkalosis with hypertension?

Liddle syndrome. ***Liddle syndrome*** - It is an **autosomal dominant** disorder characterized by a mutation in the **ENaC channel**, leading to increased sodium reabsorption and potassium excretion, thus causing **hypokalemia**, **metabolic alkalosis**, and **hypertension**. [1] - This condition mimics **primary hyperaldosteronism** but has **low plasma renin activity** and **low aldosterone levels**. [1] *Bartter syndrome* - This is a genetic disorder affecting the **Na-K-2Cl cotransporter** in the **thick ascending limb** of the loop of Henle, leading to **salt wasting** and compensatory **renin-angiotensin-aldosterone system activation**. - It presents with **hypokalemia**, **metabolic alkalosis**, but typically with **normal or low blood pressure**, not hypertension. *Gitelman syndrome* - This is an autosomal recessive disorder affecting the **thiazide-sensitive Na-Cl cotransporter** in the **distal convoluted tubule**. - It causes **hypokalemic metabolic alkalosis**, hypomagnesemia, and hypocalciuria, but patients are typically **normotensive** or **hypotensive**, distinguishing it from Liddle syndrome. *Renal tubular acidosis* - This is a group of disorders characterized by the **kidneys' inability to excrete acid** or **reabsorb bicarbonate**, leading to **metabolic acidosis**. [2] - While it can cause electrolyte abnormalities, hypokalemia is a feature of certain types (e.g., RTA type 1 and 2), but the defining feature is **metabolic acidosis**, not metabolic alkalosis, and it is not typically associated with hypertension from the primary tubular defect. [2]

Q: Which type of renal stones is associated with laxative abuse?

Uric acid stones. ***Uric acid stones*** - Chronic laxative abuse can lead to **dehydration** and **diarrhea**, causing significant fluid and bicarbonate loss. This loss results in systemic metabolic acidosis and a persistently **acidic urine pH**. [1] - A persistently **acidic urine pH** (typically below 5.5) reduces the solubility of uric acid, promoting its crystallization and the formation of uric acid stones. [1] *Ammonium urate stones* - These stones are often seen in conditions with chronic **urinary tract infections** (UTIs) caused by **urea-splitting organisms** (e.g., Proteus), especially in children or in contexts of chronic diarrhea where ammonia production is increased. - While laxative abuse can cause diarrhea, it primarily leads to an acidic urine pH rather than the alkaline pH and high ammonia concentration typically associated with ammonium urate stones. *Struvite stones* - **Struvite stones** (magnesium ammonium phosphate) are predominantly associated with **urinary tract infections** by **urea-splitting organisms** (e.g., Proteus mirabilis) that elevate urinary pH and ammonia levels. [1] - Laxative abuse leads to an acidic urine pH, which is not conducive to struvite stone formation. *Calcium oxalate stones* - **Calcium oxalate stones** are the most common type of renal stone and are usually associated with hypercalciuria, hyperoxaluria, hypocitraturia, or low urine volume. - While dehydration from laxative abuse can increase urine concentration, the primary biochemical derangement leading to uric acid stones (acidic urine) is different from the risk factors for calcium oxalate stones.

Q: Most common acute complication of dialysis is

Hypotension. ***Hypotension*** - **Intradialytic hypotension** is the most common acute complication, occurring in 15-30% of dialysis sessions. - It is often caused by rapid removal of fluid (ultrafiltration), leading to a significant drop in blood pressure [1]. *Bleeding* - While bleeding can occur due to **anticoagulation** used during dialysis or as a complication of vascular access, it is less common than hypotension. - It is not considered the most frequent acute complication of the dialysis procedure itself. *Dementia* - **Dementia** is a chronic neurological condition that is not an acute complication directly attributable to a single dialysis session. - It can be a long-term comorbidity in patients with end-stage renal disease (ESRD), but not an immediate side effect. *Muscle cramps* - **Muscle cramps** are a relatively common acute complication during or immediately after dialysis, affecting about 5-20% of patients. - However, their frequency is generally lower than that of intradialytic hypotension [1].

Q: Muehrcke lines in nails are seen in

Nephrotic syndrome. ***Nephrotic syndrome*** - **Muehrcke lines** are paired, white, transverse lines that do not move with nail growth, characteristic of **hypoalbuminemia** seen in nephrotic syndrome [1]. - These lines are caused by **edema** in the nail bed, making them visible through the nail plate. *Bartter syndrome* - Characterized by a defect in the **sodium-potassium-chloride cotransporter** in the loop of Henle, leading to electrolyte imbalances. - It does not typically present with nail changes like Muehrcke lines. *Nail-patella syndrome* - A genetic disorder causing **skeletal abnormalities**, including hypoplastic or absent patellae and nail dysplasia. - Nail changes are usually structural abnormalities (e.g., triangular lunulae, ridging), not Muehrcke lines. *Acute tubular necrosis* - Involves damage to the **renal tubules**, often causing acute kidney injury and electrolyte disturbances. - While it can lead to kidney dysfunction, it is not specifically associated with Muehrcke lines.

Q: Which of the following types of kidney stones are commonly associated with urinary tract infections?

Struvite stones. ***Struvite stones*** - **Struvite stones** (magnesium ammonium phosphate) are strongly associated with **urinary tract infections (UTIs)** caused by urease-producing bacteria like *Proteus* and *Klebsiella*. - These bacteria hydrolyze urea into ammonia and carbon dioxide, increasing urine pH and promoting the precipitation of struvite, often forming **staghorn calculi** [1]. *Cystine stones* - **Cystine stones** are caused by a **genetic defect** in amino acid transport, leading to increased excretion of cystine, ornithine, lysine, and arginine (COLA) in the urine. - They are not directly associated with UTIs but rather with a rare inherited metabolic disorder called **cystinuria**. *Xanthine stones* - **Xanthine stones** are very rare and typically occur in individuals with **xanthinuria**, a genetic disorder characterized by a deficiency in xanthine oxidase. - They are also not linked to UTIs but are a consequence of abnormal purine metabolism. *Calcium oxalate stones* - **Calcium oxalate stones** are the most common type of kidney stone, resulting from high levels of calcium and oxalate in the urine, often due to dietary factors, malabsorption, or idiopathic hypercalciuria. - While UTIs can complicate any kidney stone, **calcium oxalate stones** are not primarily *caused* by UTIs. [1]

Q: Which of the following conditions is a direct indication for initiating dialysis?

Severe hyperkalemia. ### Severe hyperkalemia - **Severe hyperkalemia** (potassium levels typically >6.5 mEq/L or rapidly rising, especially with ECG changes) is an immediate life-threatening indication for dialysis when conservative measures fail or are insufficient [1]. - Dialysis effectively removes **excess potassium** from the blood, preventing fatal cardiac arrhythmias. *Severe metabolic acidosis* - While **severe metabolic acidosis** (pH <7.1-7.2) can be an indication, it is often managed first with bicarbonate administration and is typically not a stand-alone **direct** *emergency* indication for dialysis unless accompanied by other severe features or resistance to medical therapy. - The decision to dialyze for acidosis often depends on the underlying cause, degree of renal failure, and response to initial management [2]. *Fluid overload* - **Fluid overload** is a common complication of kidney failure, but it becomes a *direct* indication for dialysis when it is **refractory to diuretic therapy** and causes life-threatening symptoms such as **pulmonary edema** [2]. - Without such refractory state and immediate danger, fluid overload itself is not always an *immediate* trigger for dialysis compared to severe hyperkalemia. *Acute kidney injury* - **Acute kidney injury** (AKI) is the underlying *condition* that can lead to indications for dialysis, but AKI itself is not a *direct indication* for dialysis. - Dialysis is initiated for the *complications* of AKI, such as refractory hyperkalemia, severe metabolic acidosis, or fluid overload, rather than the diagnosis of AKI alone [2].

Q: Polyuria with low fixed specific gravity urine is seen in ?

Chronic glomerulonephritis. ***Chronic glomerulonephritis*** - Damage to the **renal tubules** in chronic glomerulonephritis impairs their ability to concentrate urine, leading to polyuria with a **low, fixed specific gravity**. [1] - This fixed specific gravity reflects the kidneys' inability to adjust urine concentration in response to hydration status, a hallmark of **chronic kidney disease**. [2] *Diabetes mellitus* - Polyuria in diabetes mellitus is caused by **osmotic diuresis** due to high glucose levels in the urine, leading to increased urinary volume. [2] - While there is polyuria, the specific gravity is not necessarily fixed and can vary, often being high due to the presence of glucose. *Diabetes insipidus* - Diabetes insipidus causes polyuria and dilute urine due to either a deficiency of **ADH (central DI)** or renal unresponsiveness to ADH **(nephrogenic DI)**. - While it causes polyuria with low specific gravity, it's typically *not* fixed; the urine specific gravity can still fluctuate to some extent depending on the patient's hydration, or in response to ADH if it's central DI. *Potomania* - Potomania, or **primary polydipsia**, is excessive water intake that leads to dilutional hyponatremia and polyuria. - The kidneys are otherwise healthy and can still concentrate urine to some extent if water intake is restricted, preventing a truly fixed low specific gravity.

Q: All are seen in Nephrotic syndrome except

Increased protein C levels. ***Increased protein C levels*** - In **nephrotic syndrome**, there is an **increased urinary loss of anticoagulant proteins**, including **Protein C** and **Protein S**, leading to a state of **hypercoagulability**. [1] - Therefore, **Protein C levels are decreased**, not increased, making this the exception. *Atherosclerosis* - **Hyperlipidemia**, a hallmark of nephrotic syndrome, contributes significantly to **accelerated atherosclerosis** due to dysregulation of lipid metabolism. - The increased levels of **LDL cholesterol** and other lipoproteins promote plaque formation and arterial stiffening. *Thrombo-embolism* - Patients with nephrotic syndrome are at a significantly **increased risk of thromboembolic events**, such as deep vein thrombosis and pulmonary embolism, due to a **hypercoagulable state**. - This state results from the **urinary loss of anticoagulant proteins** (e.g., antithrombin III, Protein C, Protein S) and increased levels of procoagulant factors (e.g., fibrinogen, factor V, factor VIII). *Lipiduria* - **Lipiduria**, the presence of lipids in the urine, is a characteristic feature of nephrotic syndrome, often manifested as **oval fat bodies** and **fatty casts**. [1] - This occurs due to the increased glomerular permeability that allows lipoproteins to filter into the urine. [1]

Q: What condition is characterized by hypertension and hypokalemia?

Liddle's Syndrome. ***Liddle's Syndrome*** - This syndrome is characterized by **overactivity of the epithelial sodium channel (ENaC)** in the collecting ducts, leading to increased sodium reabsorption and potassium excretion. [1] - The resulting **sodium retention causes hypertension**, while the **potassium excretion leads to hypokalemia**. *Gitelman's Syndrome* - This is an **autosomal recessive kidney disorder** causing a defect in the **thiazide-sensitive NaCl cotransporter** in the distal convoluted tubule. - It presents with **hypokalemia and hypomagnesemia**, but typically with **normal or low blood pressure**, not hypertension. *Bartter Syndrome* - This is a group of **autosomal recessive salt-wasting tubulopathies** affecting the **Na-K-2Cl cotransporter** in the thick ascending limb of the loop of Henle. - It leads to **hypokalemia, metabolic alkalosis, and normal or low blood pressure**, similar to chronic loop diuretic use. *All of the options* - While all mentioned conditions involve **hypokalemia**, only **Liddle's Syndrome** is consistently associated with **hypertension**. - **Gitelman's and Bartter syndromes** typically present with **normal or low blood pressure**.

Question 1

In Bartter syndrome defect is seen in:

Accepted Answer

Defect in thick ascending limb of loop of Henle

Answer

Defect in proximal convoluted tubule (PCT)

Answer

Defect in distal convoluted tubule (DCT)

Answer

No defect

Question 2

Which of the following is a cause of hypokalemic metabolic alkalosis with hypertension?

Accepted Answer

Liddle syndrome

Answer

Bartter syndrome

Answer

Gitelman syndrome

Answer

Renal tubular acidosis

Question 3

Which type of renal stones is associated with laxative abuse?

Accepted Answer

Uric acid stones

Answer

Struvite stones

Answer

Calcium oxalate stones

Answer

Ammonium urate stones

Question 4

Most common acute complication of dialysis is

Accepted Answer

Hypotension

Answer

Bleeding

Answer

Dementia

Answer

Muscle cramps

Question 5

Muehrcke lines in nails are seen in

Accepted Answer

Nephrotic syndrome

Answer

Bartter syndrome

Answer

Nail-patella syndrome

Answer

Acute tubular necrosis

Question 6

Which of the following types of kidney stones are commonly associated with urinary tract infections?

Accepted Answer

Struvite stones

Answer

Cystine stones

Answer

Xanthine stones

Answer

Calcium oxalate stones

Question 7

Which of the following conditions is a direct indication for initiating dialysis?

Accepted Answer

Severe hyperkalemia

Answer

Severe metabolic acidosis

Answer

Fluid overload

Answer

Acute kidney injury

Question 8

Polyuria with low fixed specific gravity urine is seen in ?

Accepted Answer

Chronic glomerulonephritis

Answer

Diabetes mellitus

Answer

Diabetes insipidus

Answer

Potomania

Question 9

All are seen in Nephrotic syndrome except

Accepted Answer

Increased protein C levels

Answer

Atherosclerosis

Answer

Thrombo-embolism

Answer

Lipiduria

Question 10

What condition is characterized by hypertension and hypokalemia?

Accepted Answer

Liddle's Syndrome

Answer

Gitelman's Syndrome

Answer

Bartter Syndrome

Answer

All of the options

Nephrology — MCQs

Nephrology — MCQs

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