Nephrology Practice Questions

Q: Hyperkalemia is seen in which type of Renal Tubular Acidosis?

Type 4 RTA. **Explanation:** The hallmark of **Type 4 Renal Tubular Acidosis (RTA)**, also known as Hyperkalemic RTA, is the presence of **hyperkalemia**. This condition is primarily caused by either **aldosterone deficiency** or **aldosterone resistance** (pseudohypoaldosteronism). Aldosterone normally acts on the principal cells of the collecting duct to reabsorb sodium and secrete potassium and hydrogen ions [1]. When aldosterone action is impaired, potassium is retained in the blood, and the distal tubule fails to excrete $H^+$ ions, leading to a metabolic acidosis with high serum potassium levels. **Analysis of Incorrect Options:** * **Type 1 RTA (Distal RTA):** Characterized by a failure of distal intercalated cells to secrete $H^+$. This leads to an inability to acidify urine (pH > 5.5) and is typically associated with **hypokalemia**, as potassium is lost in exchange for sodium [2]. * **Type 2 RTA (Proximal RTA):** Caused by a defect in proximal bicarbonate reabsorption. The resulting bicarbonaturia leads to potassium wasting, typically causing **hypokalemia**. * **Type 3 RTA:** This is a rare, historical term referring to a hybrid of Type 1 and Type 2 features (seen in carbonic anhydrase II deficiency). Like Types 1 and 2, it is generally associated with **hypokalemia**. **High-Yield Clinical Pearls for NEET-PG:** * **Type 4 RTA** is the most common form of RTA in clinical practice, frequently seen in patients with **Diabetes Mellitus** (Hyporeninemic hypoaldosteronism). * **Urine pH:** In Type 4 RTA, the urine pH is typically **< 5.5** (the distal acidification mechanism is intact, but the buffer capacity is low due to low ammonia production). * **Drugs causing Type 4 RTA:** ACE inhibitors, ARBs, NSAIDs, Heparin, and Spironolactone [1]. * **Mnemonic:** "Type **4** is the only one with **High** K+" (4 looks like an 'H' for High).

Q: Broad casts in urinary sediments are specific for:

Chronic renal failure. **Explanation:** **Broad casts** (also known as "Renal Failure Casts") are a hallmark finding in **Chronic Renal Failure (CRF)** [1]. 1. **Why Chronic Renal Failure is correct:** Broad casts are significantly wider than ordinary casts. They form in the **large collecting ducts** that have undergone compensatory **dilation and hypertrophy** due to the loss of surrounding functioning nephrons [1]. This structural remodeling is a characteristic feature of end-stage renal disease or advanced chronic kidney disease (CKD) [1]. Their presence indicates severe reduction in nephron number and stasis in these dilated tubules. 2. **Why other options are incorrect:** * **Acute Renal Failure (ARF):** Typically characterized by **Muddy Brown (Granular) casts**, which represent acute tubular necrosis (ATN). The tubules have not had time to undergo the chronic dilation required to form broad casts. * **Rapidly Progressive Renal Failure (RPGN):** This is clinically associated with **Red Blood Cell (RBC) casts**, signifying glomerular inflammation (crescentic glomerulonephritis). * **Asymptomatic Urinary Abnormality:** This usually presents with isolated proteinuria or hematuria (e.g., IgA nephropathy) without the extensive tubular remodeling seen in advanced renal failure. **High-Yield Clinical Pearls for NEET-PG:** * **Broad Casts:** Specific for Chronic Renal Failure/End-stage renal disease. * **RBC Casts:** Pathognomonic for Glomerulonephritis. * **WBC Casts:** Suggestive of Pyelonephritis or Interstitial Nephritis. * **Fatty Casts ("Maltese Cross"):** Seen in Nephrotic Syndrome. * **Hyaline Casts:** Can be normal (after exercise/dehydration) or seen in concentrated urine. * **Waxy Casts:** Found in chronic renal states; they represent the final stage of granular cast degeneration.

Q: Renal osteodystrophy is characterized by all EXCEPT?

Alkaline phosphatase. **Explanation:** Renal Osteodystrophy (ROD) is a component of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD). The question asks which parameter does **not** characterize the condition. While Alkaline Phosphatase (ALP) is often elevated in high-turnover bone disease (like osteitis fibrosa cystica), it is a **non-specific marker**. It can be elevated in liver disease or other bone pathologies, making it the least characteristic diagnostic feature compared to the direct hormonal and mineral derangements of CKD. **Analysis of Options:** * **Phosphorus (B):** Hyperphosphatemia is the primary trigger. As GFR declines, phosphate excretion decreases, leading to its accumulation in the blood [2]. * **Calcium (A):** Hypocalcemia occurs due to hyperphosphatemia (calcium-phosphate precipitation) and a deficiency of 1,25-dihydroxyvitamin D (Calcitriol) because the failing kidney cannot perform 1-alpha hydroxylation [1]. * **Parathormone (D):** Secondary Hyperparathyroidism is a hallmark. Low calcium and high phosphorus stimulate the parathyroid glands to secrete PTH to mobilize calcium from bones, leading to bone resorption [2]. * **Alkaline Phosphatase (C):** While bone-specific ALP rises during active bone remodeling, it is not a defining biochemical criterion for the *pathophysiology* of ROD in the same way that the Ca-P-PTH axis is. **High-Yield Pearls for NEET-PG:** * **Sequence of events:** ↓ GFR → ↑ Phosphate → ↓ 1,25(OH)₂D₃ → ↓ Calcium → ↑ PTH [2]. * **Most common bone lesion:** Osteitis fibrosa cystica (due to high PTH) [2]. * **Adynamic Bone Disease:** Characterized by **low** PTH and **low** ALP, often due to over-suppression of the parathyroid gland [2]. * **Radiology:** "Rugger-jersey spine" is a classic sign of renal osteodystrophy.

Q: Which of the following is the common extrarenal involvement in autosomal dominant polycystic kidney disease?

Hepatic cysts. **Explanation:** Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a multisystemic disorder characterized by the growth of numerous cysts in the kidneys and various extrarenal manifestations [1]. **Why Hepatic Cysts are the Correct Answer:** **Hepatic cysts** are the **most common extrarenal manifestation** of ADPKD, occurring in approximately 70–90% of patients during their lifetime (detected via MRI). These cysts arise from the biliary epithelium. While they are numerous, they rarely lead to hepatic failure because the intervening liver parenchyma remains functional. They are more common and more extensive in females, particularly those who have been pregnant, due to the influence of estrogen. **Analysis of Incorrect Options:** * **A. Mitral Valve Prolapse (MVP):** This is the most common **valvular** abnormality in ADPKD (occurring in ~25% of patients), but it is less frequent than hepatic cysts. * **C. Splenic Cysts:** These occur in ADPKD but are much rarer (approx. 5%) compared to hepatic involvement. * **D. Colonic Diverticulosis:** There is an increased association between ADPKD and diverticulosis (and diverticulitis), especially in patients with end-stage renal disease, but it is not the most common extrarenal finding. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of death:** Cardiovascular disease (due to hypertension and LVH). * **Most common extrarenal manifestation:** Hepatic cysts. * **Most serious/dreaded complication:** Rupture of **Berry Aneurysms** (Circle of Willis), leading to Subarachnoid Hemorrhage (SAH). * **Genetics:** Mutation in **PKD1** (Chromosome 16 - 85% cases, more severe) or **PKD2** (Chromosome 4 - 15% cases [1], slower progression). * **Other associations:** Pancreatic cysts, seminal vesicle cysts, and abdominal/inguinal hernias.

Q: Which feature differentiates prerenal azotemia from acute tubular necrosis (ATN)?

Urine osmolality > 500 mosmol/kg. The differentiation between prerenal azotemia and acute tubular necrosis (ATN) hinges on the functional integrity of the renal tubules. [1] **1. Why Option A is correct:** In **prerenal azotemia**, the kidneys are structurally intact but under-perfused. To compensate for low blood volume, the tubules maximize water reabsorption under the influence of ADH. This results in highly concentrated urine with a **Urine Osmolality > 500 mOsm/kg**. In contrast, in **ATN**, the tubular cells are damaged and lose their concentrating ability (isosthenuria), typically resulting in a urine osmolality < 350 mOsm/kg. **2. Why other options are incorrect:** * **Option B:** While a low urinary sodium is characteristic of prerenal states, the standard diagnostic threshold is **< 20 mEq/L**, not < 10 mEq/L. Furthermore, Urine Osmolality is considered a more reliable physiological indicator of tubular water-handling capacity in this specific comparison. * **Option C:** The Plasma transferrin/Ig ratio is not a standard clinical parameter used to differentiate these two conditions; it is more relevant in specific proteinuric or nutritional assessments. **Clinical Pearls for NEET-PG:** To master this topic, remember the

Q: Which of the following treatments is appropriate for tall peaked T waves on ECG?

Inhaled Salbutamol. **Explanation:** **Tall peaked T waves** on an ECG are the earliest and most characteristic sign of **Hyperkalemia**. Management focuses on three goals: stabilizing the cardiac membrane, shifting potassium into cells, and removing potassium from the body. **Why Inhaled Salbutamol is correct:** Salbutamol is a $\beta_2$-adrenergic agonist. It stimulates the Na⁺/K⁺-ATPase pump in skeletal muscle, which promotes the **intracellular shift of potassium**, thereby rapidly lowering serum potassium levels. It is an effective "shifter" therapy, often used alongside insulin-dextrose. **Analysis of Incorrect Options:** * **A. Atropine IV:** Used for symptomatic bradycardia or AV blocks; it has no effect on serum potassium levels. * **B. Nitroprusside IV:** A potent vasodilator used in hypertensive emergencies; it does not treat electrolyte imbalances. * **D. Inhaled Betamethasone:** While some corticosteroids have mineralocorticoid activity that can lower potassium over long periods, inhaled steroids have no role in the acute management of hyperkalemia. **NEET-PG High-Yield Pearls:** 1. **Immediate First Step:** If the ECG shows changes (like peaked T waves or QRS widening), the first drug to administer is **IV Calcium Gluconate** (10 ml of 10%). It stabilizes the cardiac membrane but does *not* lower potassium. 2. **The "Shifters":** Insulin with Dextrose (most reliable), Inhaled Salbutamol, and IV Sodium Bicarbonate (if metabolic acidosis is present). 3. **Definitive Removal:** Loop diuretics (Furosemide), Potassium-binding resins (Patiromer, Lokelma), or **Hemodialysis** (the gold standard for refractory hyperkalemia). 4. **ECG Progression:** Peaked T waves $\rightarrow$ P wave flattening/PR prolongation $\rightarrow$ QRS widening $\rightarrow$ "Sine wave" pattern $\rightarrow$ Ventricular Fibrillation.

Question 1

Hyperkalemia is seen in which type of Renal Tubular Acidosis?

Accepted Answer

Type 4 RTA

Answer

Type 1 RTA

Answer

Type 2 RTA

Answer

Type 3 RTA

Question 2

Proximal renal tubular acidosis has all the following features except?

Accepted Answer

Nephrocalcinosis

Answer

Hypokalemia

Answer

Bicarbonate wasting

Answer

Hyperchloremia

Question 3

Broad casts in urinary sediments are specific for:

Accepted Answer

Chronic renal failure

Answer

Acute renal failure

Answer

Rapidly progressive renal failure

Answer

Asymptomatic urinary abnormality

Question 4

Renal osteodystrophy is characterized by all EXCEPT?

Accepted Answer

Alkaline phosphatase

Answer

Calcium level

Answer

Phosphorus level

Answer

Parathormone levels

Question 5

Which of the following is the common extrarenal involvement in autosomal dominant polycystic kidney disease?

Accepted Answer

Hepatic cysts

Answer

Mitral valve prolapse

Answer

Splenic cysts

Answer

Colonic diverticulosis

Question 6

What is the primary diagnostic laboratory finding in nephrotic syndrome?

Accepted Answer

Massive albuminuria

Answer

Elevated blood urea

Answer

Severe anaemia

Answer

Hyperglycemia

Question 7

A patient with autosomal dominant polycystic kidney disease (ADPKD) is taking tolvaptan and is complaining of abdominal pain and loose stools. What is the likely cause of these symptoms?

Accepted Answer

Side effects of tolvaptan

Answer

Colonic diverticulosis

Answer

Diverticulitis

Answer

Appendicitis

Question 8

During a routine physical examination, a 42-year-old female is found to have an elevated blood pressure of 150/100 mmHg. Workup reveals a small left kidney and a normal-sized right kidney. Laboratory examination reveals elevated serum renin levels, and renal vein renin levels are increased on the left but decreased on the right. This patient's hypertension is most likely the result of?

Accepted Answer

Fibromuscular hyperplasia of the left renal artery

Answer

Atherosclerotic narrowing of the left renal artery

Answer

Atherosclerotic narrowing of the right renal artery

Answer

Fibromuscular hyperplasia of the right renal artery

Question 9

Which feature differentiates prerenal azotemia from acute tubular necrosis (ATN)?

Accepted Answer

Urine osmolality > 500 mosmol/kg

Answer

Urinary sodium excretion < 10 mEq/L

Answer

Plasma transferrin/Ig ratio

Answer

All the above

Question 10

Which of the following treatments is appropriate for tall peaked T waves on ECG?

Accepted Answer

Inhaled Salbutamol

Answer

Atropine IV

Answer

Nitroprusside IV

Answer

Inhaled betamethasone

Nephrology — MCQs

Nephrology — MCQs

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