Nephrology Practice Questions

Q: A patient with acute kidney injury (creatinine > 4) has been undergoing dialysis in the ICU for 15 days and has developed deep vein thrombosis (DVT) due to immobilization. What is the most appropriate anticoagulant to administer?

Argatroban. ### Explanation The management of anticoagulation in patients with severe renal impairment (AKI or ESRD) requires careful selection based on the route of drug elimination. **Why Argatroban is the Correct Choice:** Argatroban is a parenteral Direct Thrombin Inhibitor (DTI) [1]. Its primary clinical advantage in this scenario is its **hepatic metabolism and biliary excretion**. Unlike many other anticoagulants, its clearance is independent of renal function. In a patient with a creatinine > 4 mg/dL undergoing dialysis, Argatroban can be administered without the risk of accumulation or toxicity, making it the safest choice among the options provided. **Analysis of Incorrect Options:** * **Desirudin & Lepirudin:** Both are recombinant hirudins (DTIs) that are **predominantly cleared by the kidneys**. In patients with renal failure, these drugs have a significantly prolonged half-life, leading to a high risk of life-threatening hemorrhage. (Note: Lepirudin has largely been withdrawn from many markets due to this risk and immunogenicity). * **Aspirin:** Aspirin is an antiplatelet agent, not an anticoagulant [1]. It is ineffective for the treatment of established Deep Vein Thrombosis (DVT). **NEET-PG High-Yield Pearls:** * **Drug of Choice for HIT:** Argatroban is also the preferred anticoagulant for patients with Heparin-Induced Thrombocytopenia (HIT) who have renal failure [1]. * **Monitoring:** Argatroban is monitored using **aPTT** (target 1.5–3 times the baseline). * **Renal vs. Hepatic:** Remember the mnemonic: **A**rgatroban = **A**liver (Liver/Hepatic clearance); **L**epirudin = **L**eaving via kidney (Renal clearance). * **LMWH/Fondaparinux:** These are generally contraindicated or require extreme caution/dose reduction when CrCl < 30 ml/min [1].

Q: A 72-year-old man develops acute renal failure following aortic angiography. He has gained weight, has rales at both lung bases, and is dyspneic. His fractional excretion of sodium is greater than 1. Peripheral smear shows eosinophilia, and his labs reveal an elevated erythrocyte sedimentation rate, proteinuria, and microscopic hematuria. What is the most likely cause of his renal failure?

Atheroembolic renal disease. ### Explanation **Atheroembolic Renal Disease (AERD)**, also known as cholesterol crystal embolism, is the most likely diagnosis. This condition occurs when cholesterol crystals are dislodged from atherosclerotic plaques in the aorta during invasive vascular procedures (like aortic angiography) [1]. **Why Option B is Correct:** The clinical triad of **recent vascular intervention**, **acute/subacute renal failure**, and **systemic inflammatory markers** is classic for AERD [1]. * **Inflammatory markers:** The presence of **eosinophilia**, elevated ESR, and low complement levels (hypocomplementemia) are hallmark features [1]. * **Urinalysis:** Unlike pure Acute Tubular Necrosis (ATN), AERD often presents with mild proteinuria and microscopic hematuria [1]. * **FENa > 1%:** This indicates intrinsic renal damage rather than a pre-renal state. **Why the Other Options are Incorrect:** * **A. Hypovolemia:** While it causes renal failure, it presents with a **FENa < 1%**, clear lungs, and no eosinophilia. * **C. Acute Tubular Necrosis (ATN):** Contrast-induced nephropathy (a form of ATN) is a common differential post-angiography. However, ATN does **not** typically cause eosinophilia or an elevated ESR [1]. * **D. Cardiogenic Shock:** While the patient has rales and dyspnea, there is no mention of hypotension or poor peripheral perfusion. **High-Yield Clinical Pearls for NEET-PG:** * **Pathognomonic finding:** Skin involvement like **Livedo Reticularis** or "Blue Toe Syndrome" (purple toes with palpable pulses) [1]. * **Histopathology:** Kidney biopsy shows pathognomonic **"Hollenhorst plaques"** or needle-shaped cholesterol clefts within the lumen of small arteries. * **Management:** Primarily supportive; avoid further anticoagulation as it may prevent the stabilization of the plaque [1].

Q: Heroin abuse is associated with which type of glomerulonephritis?

Focal segmental glomerulosclerosis. **Explanation:** **Heroin-Associated Nephropathy (HAN)** is a classic clinical entity characterized by the development of **Focal Segmental Glomerulosclerosis (FSGS)** [1]. 1. **Why FSGS is correct:** Intravenous heroin use leads to a specific form of secondary FSGS [1]. The pathophysiology involves direct toxicity to podocytes [2], chronic inflammation, and potential contaminants in the drug. Patients typically present with massive proteinuria (nephrotic syndrome) [2] and a rapid progression to End-Stage Renal Disease (ESRD). On biopsy, it shows segmental scarring of some (but not all) glomeruli, similar to the collapsing variant seen in HIV-associated nephropathy (HIVAN) [1]. 2. **Why other options are incorrect:** * **Crescentic GN:** This is the hallmark of Rapidly Progressive Glomerulonephritis (RPGN) [3], associated with conditions like Goodpasture syndrome [4] or ANCA-associated vasculitis, not typically heroin. * **Membranous GN:** This is most commonly associated with Hepatitis B, Hepatitis C, gold therapy, or malignancies. While heroin users may have Hep B/C, the direct association of heroin itself is with FSGS [3]. * **Diffuse Proliferative GN:** This is the classic pattern for SLE (Class IV) or post-streptococcal GN [1]. **High-Yield Clinical Pearls for NEET-PG:** * **The "Collapsing" Variant:** Both Heroin and HIV are strongly associated with the collapsing variant of FSGS, which has the worst prognosis. * **Race Factor:** HAN is significantly more common in the African American population. * **Differential Diagnosis:** If a question mentions an IV drug user with **fever and hematuria**, think of **Staph. aureus Endocarditis** leading to Post-Infectious GN. If it mentions **painless nephrotic syndrome**, think of **FSGS**. * **Other FSGS associations:** Obesity, Sickle Cell Disease, and Pamidronate use.

Q: What is the new indication of tolvaptan as approved by FDA recently?

Polycystic kidney disease. **Explanation:** **Tolvaptan** is a selective, competitive **Vasopressin V2-receptor antagonist**. While it was initially approved for the treatment of hyponatremia (SIADH, heart failure, and cirrhosis), its most significant recent FDA approval is for **Autosomal Dominant Polycystic Kidney Disease (ADPKD)** [1]. **Why Polycystic Kidney Disease (PKD) is correct:** In ADPKD, arginine vasopressin (AVP) levels are often elevated. AVP binds to V2 receptors in the renal collecting ducts, increasing intracellular cyclic AMP (cAMP). This cAMP stimulates both the proliferation of cyst-lining epithelial cells and the secretion of fluid into the cysts. By blocking V2 receptors, Tolvaptan lowers cAMP levels, thereby **slowing the rate of cyst growth** and the decline in glomerular filtration rate (GFR). It is specifically indicated for adults at risk of rapidly progressing ADPKD [1]. **Why the other options are incorrect:** * **Phenylketonuria (A):** This is a metabolic disorder of amino acid metabolism (phenylalanine hydroxylase deficiency) treated primarily via dietary restriction, not vasopressin modulation. * **Pancreatic tumours (B):** Tolvaptan has no established role in the management of pancreatic oncology. * **Polycystic ovarian disease (C):** PCOS is an endocrine disorder involving insulin resistance and androgen excess; it does not involve the V2-receptor pathway. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** V2-receptor antagonist (Aquaretic). * **Major Side Effect:** Significant risk of **hepatotoxicity** (requires regular LFT monitoring). * **Common Side Effects:** Polyuria, thirst, and xerostomia (due to increased free water excretion). * **Contraindication:** Patients with underlying significant liver disease or those unable to sense/respond to thirst.

Question 1

A patient with acute kidney injury (creatinine > 4) has been undergoing dialysis in the ICU for 15 days and has developed deep vein thrombosis (DVT) due to immobilization. What is the most appropriate anticoagulant to administer?

Accepted Answer

Argatroban

Answer

Desirudin

Answer

Lepirudin

Answer

Aspirin

Question 2

High serum uric acid, high serum phosphates, and high serum creatinine in a patient will be observed in which of the following conditions?

Accepted Answer

Chronic lymphocytic leukemia

Answer

Obstructive jaundice

Answer

Status epilepticus

Answer

Typhoid

Question 3

All of the following are seen in Hemolytic Uremic Syndrome (HUS) except?

Accepted Answer

Altered sensorium

Answer

Thrombocytopenia

Answer

Hemolytic anemia

Answer

Renal failure

Question 4

Which of the following symptoms do you expect to see in a patient diagnosed with acute pyelonephritis?

Accepted Answer

Costovertebral angle tenderness and chills

Answer

Jaundice and flank pain

Answer

Burning sensation on urination

Answer

Polyuria and nocturia

Question 5

Which of the following statements about prerenal azotaemia is false?

Accepted Answer

Parenchymal damage to kidney

Answer

Physiological response to renal hypoperfusion

Answer

Certain drugs can provoke acute prerenal failure

Answer

Persistent renal hypoperfusion leads to ischaemic acute tubular necrosis

Question 6

What is the leading cause of hyperkalemia?

Accepted Answer

Reduced renal excretion

Answer

Redistribution of potassium

Answer

Adrenal neurohormonal surge

Answer

Drugs

Question 7

Which disease recurs after kidney transplantation?

Accepted Answer

Systemic Lupus Erythematosus

Answer

Diabetes Mellitus

Answer

Membranoproliferative Glomerulonephritis

Answer

Mesangial proliferative glomerulonephritis

Question 8

A 72-year-old man develops acute renal failure following aortic angiography. He has gained weight, has rales at both lung bases, and is dyspneic. His fractional excretion of sodium is greater than 1. Peripheral smear shows eosinophilia, and his labs reveal an elevated erythrocyte sedimentation rate, proteinuria, and microscopic hematuria. What is the most likely cause of his renal failure?

Accepted Answer

Atheroembolic renal disease

Answer

Hypovolemia

Answer

Acute tubular necrosis

Answer

Cardiogenic shock

Question 9

Heroin abuse is associated with which type of glomerulonephritis?

Accepted Answer

Focal segmental glomerulosclerosis

Answer

Crescentic glomerulonephritis

Answer

Membranous glomerulonephritis

Answer

Diffuse proliferative glomerulonephritis

Question 10

What is the new indication of tolvaptan as approved by FDA recently?

Accepted Answer

Polycystic kidney disease

Answer

Phenylketonuria

Answer

Pancreatic tumours

Answer

Polycystic ovarian disease

Nephrology — MCQs

Nephrology — MCQs

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