Nephrology — MCQs

Nephrology Indian Medical PG Practice Questions and MCQs

Question 801: Which of the following is a characteristic finding in distal RTA?

A. Urine pH < 5.5
B. Hypokalemia
C. Hypercalciuria (Correct Answer)
D. Nephrolithiasis

Explanation: ***Hypercalciuria*** - **Hypercalciuria** is a characteristic finding in distal RTA (Type 1), leading to increased calcium in the urine. - This occurs due to reduced **distal tubular reabsorption of calcium** and increased bone resorption from chronic acidosis. *Urine pH < 5.5* - In distal RTA, the kidneys are unable to acidify the urine properly, leading to a **urine pH > 5.5** [1]. - A urine pH < 5.5 would suggest a normal kidney response to systemic acidosis, ruling out distal RTA. *Hypokalemia* - While hypokalemia can occur in distal RTA, it is not always present and is not the most definitive characteristic finding. - **Hypokalemia** is more characteristic of Type 1 RTA due to increased potassium excretion in an attempt to excrete H+ ions. *Nephrolithiasis* - **Nephrolithiasis** (kidney stones) is a common complication of distal RTA due to hypercalciuria and alkaline urine [2]. - However, hypercalciuria is the *reason* for the increased risk of nephrolithiasis, making it a more fundamental characteristic finding.

Question 802: Which of the following is not an absolute indication for hemodialysis?

A. GI bleeding (Correct Answer)
B. Convulsions
C. Pericarditis
D. Hyperkalemia of 6.5 mEq/L

Explanation: ***GI bleeding*** - While patients on dialysis may experience gastrointestinal bleeding, it is not a direct indication for initiating or continuing **hemodialysis**. - **GI bleeding** in end-stage renal disease (ESRD) patients can be due to various causes and requires specific management of the bleeding itself, not necessarily an alteration in dialysis prescription. *Convulsions* - **Convulsions** in patients with renal failure, especially due to uremia, are a severe manifestation of **uremic encephalopathy**. - This is an absolute indication for **hemodialysis** as it rapidly removes uremic toxins causing central nervous system dysfunction. *Pericarditis* - **Uremic pericarditis**, characterized by inflammation of the pericardium due to accumulation of uremic toxins, is a serious complication of renal failure. - It is an absolute indication for **hemodialysis** to prevent further cardiac complications like cardiac tamponade. *Hyperkalemia of 6.5 mEq/L* - Severe **hyperkalemia** (typically > 6.0-6.5 mEq/L) is a life-threatening electrolyte imbalance that can cause cardiac arrhythmias. - **Hemodialysis** is highly effective in rapidly removing potassium from the body and is an absolute indication, especially if unresponsive to other medical therapies.

Question 803: Which of the following is not a feature of distal renal tubular acidosis

A. Renal hypercalciuria
B. Normal anion gap
C. Hyperkalemia (Correct Answer)
D. Alkaline urine

Explanation: ***Hyperkalemia*** - **Distal renal tubular acidosis (dRTA)** is characterized by impaired acid excretion, leading to metabolic acidosis. The impaired excretion of acid is often accompanied by impaired potassium secretion, resulting in **hypokalemia**, not hyperkalemia. - While hyperkalemia is a feature of **type 4 RTA**, which is characterized by hypoaldosteronism or renal tubular unresponsiveness to aldosterone, it is not a feature of **distal RTA (type 1)**. [1] *Normal anion gap* - **Distal RTA** is a form of **normal anion gap metabolic acidosis**, also known as **hyperchloremic metabolic acidosis**. [1] - The anion gap is calculated as [Na+] - ([Cl-] + [HCO3-]), and in dRTA, the bicarbonate loss is compensated by an increase in chloride, maintaining a normal anion gap. *Renal hypercalciuria* - **Distal RTA** is associated with **impaired acid excretion**, which leads to chronic metabolic acidosis. - This **acidosis** promotes the dissolution of bone, releasing calcium, and decreases tubular reabsorption of calcium, resulting in **hypercalciuria**. *Alkaline urine* - In **distal RTA**, the distal tubule is unable to acidify the urine due to a defect in hydrogen ion secretion. - This leads to a persistent **urine pH > 5.5** (typically alkaline or inappropriately normal) despite systemic acidosis, making it a key diagnostic feature. [1]

Question 804: Calciphylaxis is a severe life-threatening condition. Which of the following is most commonly associated with it?

A. Parathyroidectomy
B. Medullary carcinoma thyroid
C. Hyperthyroidism
D. End stage Renal disease (Correct Answer)

Explanation: ***End stage Renal disease*** - Calciphylaxis frequently occurs in patients with **end-stage renal disease**, primarily associated with **secondary hyperparathyroidism** [1] and **calcium-phosphate imbalance**. - It leads to **cutaneous ischemia** and necrosis, often requiring aggressive management due to its high **mortality rate**. *Parathyroidectomy* - While parathyroidectomy may affect calcium levels, it is not directly linked to calciphylaxis. - Calciphylaxis more commonly develops due to underlying **chronic renal failure** [1] rather than surgical interventions. *Hyperthyroidism* - Hyperthyroidism primarily causes symptoms related to metabolism, **thyroid hormone excess**, and does not lead to calciphylaxis. - There is no direct correlation between hyperthyroid states and the pathophysiology of calciphylaxis. *Medullary carcinoma thyroid* - This condition involves **medullary thyroid carcinoma**, associated with calcitonin production and does not cause calciphylaxis. - Patients typically experience **thyroid-related symptoms** rather than the vascular complications seen in calciphylaxis.

Question 805: What is the recommended rate of correction for sodium deficit in patients with chronic hyponatremia?

A. 0.5 mmol/hour (Correct Answer)
B. 1 mmol/hour
C. 1.5 mmol/hour
D. 2.0 mmol/hour

Explanation: ***0.5 mmol/hour*** [1] - This rate of correction is recommended to avoid **osmotic demyelination syndrome (ODS)**, also known as central pontine myelinolysis [1]. - The aim is to correct the sodium deficit gradually, with a maximum increase not exceeding **8-10 mmol/L in any 24-hour period** [1]. *1 mmol/hour* - This rate is generally considered too rapid for chronic hyponatremia and increases the risk of **osmotic demyelination syndrome**. - While acceptable in some acute severe cases, it is typically avoided in chronic settings where the brain has adapted to lower osmolality. *1.5 mmol/hour* - This rate would lead to an even faster correction of sodium, significantly elevating the risk of **osmotic demyelination syndrome**. - It would result in a correction of 36 mmol/L over 24 hours, far exceeding the recommended daily limit of 8-10 mmol/L. *2.0 mmol/hour* - Such a rapid correction rate is highly dangerous and almost guarantees the development of **osmotic demyelination syndrome**. - This aggressive correction would lead to severe brain injury due to rapid osmotic shifts.

Question 806: Which of the following statements about Alport's syndrome is incorrect?

A. Nerve deafness
B. Glomerulonephritis
C. Autosomal dominant (Correct Answer)
D. X-linked

Explanation: ***Autosomal dominant*** - While there are rare autosomal dominant forms, the most common and classic presentation of **Alport's syndrome is X-linked recessive**, affecting males more severely. - This statement is incorrect because it implies that autosomal dominant inheritance is the primary or typical mode, which is not true for the majority of cases. *Nerve deafness* - **Sensorineural hearing loss**, particularly for high frequencies, is a common and characteristic extra-renal manifestation of Alport's syndrome. - This symptom typically progresses with age and is a key diagnostic feature. *Glomerulonephritis* - **Progressive glomerulonephritis** is the hallmark renal feature of Alport's syndrome, leading to hematuria, proteinuria, and eventually end-stage renal disease. - It is caused by mutations in collagen type IV genes, which disrupt the integrity of the glomerular basement membrane. *X-linked* - The majority of Alport's syndrome cases (about 85%) are **X-linked recessive**, caused by mutations in the *COL4A5* gene located on the X chromosome. - This explains why males are more severely affected and typically present with earlier onset and more rapid progression of renal disease.

Question 807: Which of the following statements about HIV associated nephropathy (HIVAN) is incorrect?

A. HIVAN is characterized by proteinuria.
B. HIVAN is associated with shrunken kidneys. (Correct Answer)
C. HIVAN typically develops when CD4 count is less than 200.
D. About 15% of cases show mesangial proliferation.

Explanation: ***Shrunken kidneys*** - In HIV-associated nephropathy, kidneys typically appear **enlarged** due to hyperplasia of podocytes and other glomerular changes. - **Shrunken kidneys** are not a characteristic feature, making this statement incorrect. *Develops when CD4<200* - HIV-associated nephropathy often arises when CD4 counts drop **below 200 cells/mm³**, indicating severe immunosuppression. - This is a common threshold for the occurrence of opportunistic infections and kidney issues in HIV patients. *15% cases show mesengial proliferation* - **Mesangial proliferation** can occur in about **15% to 30%** of cases of HIV-associated nephropathy, which aligns with the typical histological findings. - Incorrect assumptions might stem from misunderstanding the varying morphologies associated with HIV nephropathy. *Proteinuria* - **Proteinuria** is a common clinical feature of HIV-associated nephropathy, with the condition often presenting with significant protein loss in the urine. - The nephropathy especially results in **nephrotic syndrome**, characterized by high levels of proteinuria.

Question 808: Distal renal tubular acidosis is associated with:

A. Hypocitraturia
B. Oxalate stones
C. Calcium stones (Correct Answer)
D. Uric acid stones

Explanation: ***Calcium stones*** - Distal renal tubular acidosis (Type 1 RTA) causes metabolic acidosis due to impaired distal tubular **hydrogen ion secretion**. - This leads to **increased urinary calcium excretion** (hypercalciuria) and decreased urinary citrate, creating an environment favorable for the formation of **calcium phosphate renal stones**. *Oxalate stones* - While oxalate is a component of some calcium stones (calcium oxalate), **primary hyperoxaluria** or dietary excess of oxalate are the main causes, not directly distal RTA. - Distal RTA specifically promotes **calcium phosphate stone formation** due to pH changes and hypercalciuria. *Hypocitraturia* - **Hypocitraturia** is indeed a feature of distal RTA as the kidney attempts to excrete acid by reabsorbing citrate, making the urine less inhibitory to stone formation. - However, the most direct and common clinically observed consequence in stone formation is the development of **calcium stones**, as hypocitraturia combined with hypercalciuria facilitates their formation. *Uric acid stones* - **Uric acid stones** typically form in persistently **acidic urine** and are associated with conditions like gout or myeloproliferative disorders. - While distal RTA results in systemic acidosis, the urine pH in distal RTA is typically **alkaline or inappropriately neutral**, which does not favor uric acid stone formation.

Question 809: What is the best treatment for anemia in patients with Chronic Renal Failure (CRF)?

A. Oral Iron Therapy
B. Erythropoietin Stimulating Agents (Correct Answer)
C. Blood transfusion
D. Androgenic Steroids

Explanation: ***Erythropoietin Stimulating Agents*** - **Erythropoietin Stimulating Agents (ESAs)** are the cornerstone of anemia treatment in CRF because the primary cause of anemia in these patients is inadequate production of **endogenous erythropoietin** by the damaged kidneys [1]. - ESAs stimulate the bone marrow to produce red blood cells, effectively reversing the anemia and improving symptoms like fatigue and exercise intolerance [1]. *Oral Iron Therapy* - While **iron deficiency** often coexists with **anemia of chronic disease** in CRF patients, oral iron alone is usually insufficient to correct the anemia; it only addresses the iron component. - Many CRF patients have **functional iron deficiency** due to chronic inflammation, which impairs iron utilization, making oral iron less effective even with adequate stores. *Blood transfusion* - **Blood transfusions** provide a rapid increase in hemoglobin but are not the preferred long-term treatment for anemia in CRF due to risks of **iron overload**, **alloreactions**, and potential sensitization, which can complicate future transplantation. - Transfusions are typically reserved for acute, severe anemia or specific circumstances where ESAs are ineffective or contraindicated. *Androgenic Steroids* - **Androgenic steroids** can stimulate erythropoiesis, but their use is limited due to significant side effects such as **hepatotoxicity**, **virilization**, and **cardiac complications**, making them a less favorable option compared to ESAs. - They are considered a secondary or tertiary option, often in patients unresponsive to primary treatments or when other options are exhausted.

Question 810: Which of the following is a renal-specific nephropathy associated with HIV?

A. Focal Segmental Glomerulosclerosis (FSGS) (Correct Answer)
B. Mesangioproliferative Glomerulonephritis
C. Membranous Nephropathy
D. Membranoproliferative Glomerulonephritis (MPGN)

Explanation: ### Focal Segmental Glomerulosclerosis - It is a common renal complication associated with **HIV infection**, characterized by **podocyte injury** and segmental sclerosis [1]. - Often results in **nephrotic syndrome**, presenting with significant **proteinuria** and edema, making it distinct in HIV renal pathology [1]. ### Membranous Glomerulonephritis - Typically presents with **subepithelial immune complex deposits**, leading to a different pathophysiological mechanism. - More commonly associated with other secondary causes, such as **drugs** or **infection**, rather than being specific to HIV. ### Mesangioproliferative Glomerulonephritis - Characterized by **mesangial cell proliferation and immune complex deposition**, often linked with various infections but not specifically with HIV. - Usually shows **hematuria** and mild proteinuria, lacking the severe nephrotic syndrome seen in focal segmental glomerulosclerosis. ### Membranoproliferative Glomerulonephritis - Features **proliferation of mesangial and endothelial cells**, leading to a distinctive pattern on renal biopsy, not specific to HIV. - Typically presents in other contexts such as **chronic infections** or **autoimmune diseases**, rather than predominantly with HIV.

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Acute Kidney Injury

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Chronic Kidney Disease

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Glomerular Diseases

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Tubulointerstitial Diseases

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Nephrotic and Nephritic Syndromes

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Urinary Tract Infections

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Renal Replacement Therapy

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Fluid and Electrolyte Disorders

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Acid-Base Disorders

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Kidney in Systemic Diseases

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Kidney Stones and Obstructive Uropathy

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Hypertension in Kidney Disease

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Nephrology — MCQs

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