Nephrology Practice Questions

Q: A 43-year-old man had a subarachnoid hemorrhage from an intracranial aneurysm 8 years ago. He has also had progressive renal impairment associated with hematuria. What is the most likely diagnosis?

polycystic kidney disease. **Explanation:** The clinical presentation of a middle-aged patient with a history of **intracranial aneurysm (Subarachnoid Hemorrhage)** and progressive **renal impairment with hematuria** is a classic description of **Autosomal Dominant Polycystic Kidney Disease (ADPKD)**. **1. Why ADPKD is correct:** ADPKD is the most common inherited kidney disease. It is characterized by the growth of numerous cysts in the kidneys, which eventually lead to renal failure and hematuria (due to cyst rupture) [1]. A key extra-renal manifestation of ADPKD is **berry aneurysms** in the Circle of Willis; rupture of these aneurysms leads to subarachnoid hemorrhage (SAH). Approximately 5-10% of ADPKD patients develop intracranial aneurysms. **2. Why other options are incorrect:** * **Medullary Sponge Kidney:** This is a congenital dilation of collecting ducts [2]. While it can cause hematuria and stones, it is typically a benign condition that does not lead to progressive renal failure or intracranial aneurysms. * **Medullary Cystic Disease (Nephronophthisis):** This presents with small kidneys and tubulointerstitial fibrosis leading to polyuria and salt wasting [2]. It does not typically present with hematuria or berry aneurysms. * **Bartter Syndrome:** This is a renal tubular defect (thick ascending limb) presenting as hypokalemic metabolic alkalosis with normal blood pressure. It does not cause renal cysts or aneurysms. **Clinical Pearls for NEET-PG:** * **Genetics:** Most cases are due to mutations in **PKD1** (Chromosome 16 - more severe) or **PKD2** (Chromosome 4) [1]. * **Extra-renal manifestations:** Hepatic cysts (most common), Berry aneurysms, Mitral Valve Prolapse (MVP), and Diverticulosis. * **Diagnosis:** Ultrasonography is the initial screening modality of choice. * **Management:** Tolvaptan (Vasopressin V2 receptor antagonist) is used to slow disease progression.

Q: Which one of the following is not a feature of type I renal tubular acidosis?

Increased anion gap. Renal Tubular Acidosis (RTA) is characterized by a **Normal Anion Gap Metabolic Acidosis (NAGMA)**. In NAGMA, the loss of bicarbonate is compensated by a reciprocal increase in serum chloride levels (hyperchloremic acidosis), keeping the anion gap within the normal range (8–12 mEq/L) [1]. Therefore, an **Increased Anion Gap** is not a feature of Type I RTA; it is instead seen in conditions like ketoacidosis, lactic acidosis, or renal failure [1]. **Analysis of Options:** * **Option A (Lower tubule re-absorption of calcium):** In Type I RTA, chronic metabolic acidosis leeches calcium from bones and inhibits distal tubule calcium reabsorption. This leads to hypercalciuria, often resulting in nephrolithiasis and nephrocalcinosis. * **Option B (Defective bicarbonate absorption in distal tubule):** While Type I is primarily a defect in **hydrogen ion (H+) secretion** by the alpha-intercalated cells, this failure to acidify urine prevents the "regeneration" and reclamation of bicarbonate, leading to a systemic deficit. * **Option C (Low serum potassium level):** Hypokalemia is a hallmark of Type I RTA. To compensate for the inability to secrete H+, the distal tubule increases potassium secretion to maintain electrical neutrality. **High-Yield Clinical Pearls for NEET-PG:** * **Type I (Distal) RTA:** Urinary pH is characteristically **> 5.5** (inability to acidify urine despite systemic acidosis) [1]. * **Associations:** Often associated with autoimmune diseases like Sjögren’s syndrome or Amphotericin B toxicity. * **Mnemonic:** Remember **"Distal = Stone"** (Type I is associated with kidney stones, whereas Type II/Proximal is not). * **Anion Gap Rule:** All RTAs (Type I, II, and IV) present with **NAGMA**. If a question mentions an elevated anion gap, look for causes other than RTA.

Q: Which of the following is not seen in Alport syndrome?

Massive proteinuria. **Explanation:** Alport syndrome is a hereditary type IV collagen disorder caused by mutations in the genes encoding the $\alpha$-3, $\alpha$-4, or $\alpha$-5 chains of type IV collagen [1]. This collagen is a vital structural component of the glomerular basement membrane (GBM), the cochlea, and the lens of the eye. **Why Massive Proteinuria is the correct answer:** Alport syndrome typically presents as a **nephritic syndrome**, not a nephrotic syndrome. While mild-to-moderate proteinuria develops as the disease progresses toward chronic kidney disease, **massive (nephrotic-range) proteinuria** is not a characteristic or early feature. The hallmark is persistent microscopic or gross hematuria due to the thinning and subsequent splitting of the GBM [1]. **Analysis of incorrect options:** * **A. Hematuria:** This is the most common and earliest clinical manifestation. It is often persistent and exacerbated by upper respiratory infections. * **B. Lenticonus:** Anterior lenticonus (conical protrusion of the lens) is a pathognomonic ocular finding in Alport syndrome, occurring in about 25% of X-linked cases. * **C. Autosomal recessive inheritance:** While the **X-linked dominant** form (COL4A5 mutation) is the most common (85%), Alport syndrome can also be inherited in **autosomal recessive** and autosomal dominant patterns (COL4A3 or COL4A4 mutations). **Clinical Pearls for NEET-PG:** 1. **Electron Microscopy:** Shows the classic **"Basket-weave appearance"** due to irregular thinning and thickening of the GBM with lamellation of the lamina densa [1]. 2. **Clinical Triad:** Hereditary nephritis (hematuria/ESRD), Sensorineural hearing loss (bilateral, high-frequency), and Ocular defects (Anterior lenticonus). 3. **Goodpasture Syndrome connection:** Patients with Alport syndrome who undergo kidney transplantation may develop anti-GBM antibodies against the "new" collagen, leading to post-transplant glomerulonephritis.

Question 1

Dementia in a patient with chronic renal failure undergoing chronic hemodialysis is most commonly due to which of the following?

Accepted Answer

Aluminium toxicity

Answer

Uremia

Answer

Cerebral amyloid angiopathy

Answer

Beta-amyloid deposition

Question 2

A 43-year-old man had a subarachnoid hemorrhage from an intracranial aneurysm 8 years ago. He has also had progressive renal impairment associated with hematuria. What is the most likely diagnosis?

Accepted Answer

polycystic kidney disease

Answer

medullary sponge kidney

Answer

medullary cystic disease

Answer

Bartter syndrome

Question 3

A 60-year-old diabetic woman with a creatinine of 2.2 requires a coronary angiogram for evaluation of coronary artery disease. Which of the following is the most effective in reducing the risk of contrast-induced nephropathy?

Accepted Answer

Give IV hydration with normal saline or sodium bicarbonate prior to and following the procedure.

Answer

Administer mannitol immediately after the contrast is given.

Answer

Perform prophylactic hemodialysis after the procedure.

Answer

Administer indomethacin 25 mg the morning of the procedure.

Question 4

A patient presents with hypovolemia and a serum sodium level of 154 mEq/L. What is the initial treatment recommended?

Accepted Answer

Normal saline

Answer

Half normal saline with 5% dextrose

Answer

Dextran 40

Answer

Ringer's lactate

Question 5

20 mEq (mmol) of potassium chloride in 500 ml of 5% dextrose solution is given intravenously to treat which of the following?

Accepted Answer

Metabolic alkalosis

Answer

Respiratory alkalosis

Answer

Metabolic acidosis

Answer

Respiratory acidosis

Question 6

What are the characteristic electrolyte imbalances associated with Congestive Heart Failure (CHF)?

Accepted Answer

Hypervolemic hyponatremia with urinary sodium < 20 mEq/L

Answer

Hypovolemic hyponatremia with urinary sodium < 20 mEq/L

Answer

Euvolemic hyponatremia with urinary sodium < 20 mEq/L

Answer

None of the above

Question 7

What has the maximum chance of infection in dialysis?

Accepted Answer

Venous catheter

Answer

AV fistula

Answer

Tunnel catheter

Answer

AV graft fistula

Question 8

Which one of the following is not a feature of type I renal tubular acidosis?

Accepted Answer

Increased anion gap

Answer

Lower tubule re-absorption of calcium

Answer

Defective bicarbonate absorption in distal tubule

Answer

Low serum potassium level

Question 9

Which of the following is not seen in Alport syndrome?

Accepted Answer

Massive proteinuria

Answer

Hematuria

Answer

Lenticonus

Answer

Autosomal recessive inheritance

Question 10

Chinese herb nephropathy is caused by which of the following?

Accepted Answer

Aristolochic acid

Answer

Mushroom

Answer

Lead poisoning

Answer

Tenofovir

Nephrology — MCQs

Nephrology — MCQs

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