Nephrology Practice Questions

Q: Which of the following is NOT a part of "Triple therapy" immunosuppression for a post-renal transplant patient?

Belatacept. The "Triple Therapy" regimen is the gold standard for maintenance immunosuppression in post-renal transplant patients. It is designed to target different pathways of the immune response to maximize graft survival while minimizing the toxicity of any single drug. ### **Explanation of the Correct Answer** **D. Belatacept:** This is a selective T-cell costimulation blocker (binds to CD80 and CD86). While it is FDA-approved for prophylaxis of organ rejection, it is **not** part of the classic "Triple Therapy" regimen. It is typically used as an alternative to Calcineurin Inhibitors (CNIs) to avoid nephrotoxicity, but it is administered via intravenous infusion rather than the standard oral triple-drug protocol. ### **Analysis of Incorrect Options** The classic Triple Therapy consists of one drug from each of the following three categories: * **A. Prednisone (Corticosteroids):** Provides broad anti-inflammatory and immunosuppressive effects by inhibiting cytokine gene expression. * **B. Cyclosporine (Calcineurin Inhibitors):** Inhibits IL-2 production. In modern practice, **Tacrolimus** has largely replaced Cyclosporine due to better efficacy, but both are considered the "backbone" of triple therapy. * **C. Azathioprine (Antimetabolites):** Inhibits purine synthesis to prevent T-cell proliferation. In contemporary regimens, **Mycophenolate Mofetil (MMF)** is more commonly used than Azathioprine. ### **NEET-PG High-Yield Pearls** * **Standard Modern Triple Therapy:** Tacrolimus + Mycophenolate Mofetil (MMF) + Prednisolone. * **Side Effect Profile:** * **Cyclosporine:** Nephrotoxicity, Gingival hyperplasia, Hirsutism. * **Tacrolimus:** Nephrotoxicity, Neurotoxicity, Post-transplant Diabetes Mellitus (PTDM). * **MMF:** GI upset and Bone marrow suppression. * **Sirolimus (mTOR inhibitor):** Often used if CNIs must be withdrawn due to nephrotoxicity, but it impairs wound healing.

Q: What does the delta gap compare?

Change in anion gap with bicarbonate. **Explanation:** The **Delta Gap** (also known as the Delta-Delta) is a clinical calculation used to assess complex acid-base disorders, specifically when a High Anion Gap Metabolic Acidosis (HAGMA) is present. **Why the correct answer is right:** The fundamental principle of HAGMA is that for every unit increase in the Anion Gap (due to unmeasured anions like lactate or ketones), there should be a corresponding molar decrease in bicarbonate ($HCO_3^-$) as it buffers the added acid. The Delta Gap compares the **change in Anion Gap ($\Delta AG$)** to the **change in Bicarbonate ($\Delta HCO_3^-$)**. * **Formula:** $\Delta \text{Gap} = (\text{Measured AG} - 12) / (24 - \text{Measured } HCO_3^-)$ * A ratio of **1 to 2** suggests a pure HAGMA. * A ratio **> 2** suggests a concurrent Metabolic Alkalosis. * A ratio **< 1** suggests a concurrent Normal Anion Gap Metabolic Acidosis (NAGMA). **Why incorrect options are wrong:** * **Options A, B, and D:** While Sodium ($Na^+$), Potassium ($K^+$), and Chloride ($Cl^-$) are components used to calculate the initial Anion Gap ($AG = Na^+ - [Cl^- + HCO_3^-]$), the Delta Gap specifically evaluates the *relationship* between the excess anions and the buffering capacity of bicarbonate. It does not compare the AG change to cations ($Na, K$) or chloride in isolation. **High-Yield Clinical Pearls for NEET-PG:** * **Normal Anion Gap:** 8–12 mEq/L. * **Winter’s Formula:** Used to calculate expected $pCO_2$ compensation in metabolic acidosis ($1.5 \times HCO_3^- + 8 \pm 2$). * **MUDPILES:** Mnemonic for HAGMA causes (Methanol, Uremia, DKA, Propylene glycol, Iron/INH, Lactate, Ethylene glycol, Salicylates). * **Key Rule:** If the Delta Gap is significantly elevated (>2), always look for a hidden metabolic alkalosis (e.g., vomiting or diuretic use).

Q: All of the following antibiotics are known to cause acute interstitial nephritis, except?

Aminoglycosides. **Explanation:** Acute Interstitial Nephritis (AIN) is a classic **Type IV hypersensitivity reaction** (delayed-type) occurring in the renal interstitium, most commonly triggered by drugs. **Why Aminoglycosides are the correct answer:** Aminoglycosides (e.g., Gentamicin, Amikacin) do not cause AIN. Instead, they are the classic cause of **Acute Tubular Necrosis (ATN)**. They cause direct dose-dependent toxicity to the proximal convoluted tubule cells. Clinically, this manifests as non-oliguric renal failure occurring 5–10 days after starting therapy, unlike the idiosyncratic, non-dose-dependent nature of AIN. **Why the other options are incorrect:** * **Sulphonamides:** These are among the most common triggers for drug-induced AIN. They can also cause crystalluria and obstructive uropathy. * **Ciprofloxacin:** Fluoroquinolones are well-documented causes of AIN. They may also present with granulomatous findings on renal biopsy. * **Erythromycin:** While less common than Penicillins or NSAIDs, Macrolides (including Erythromycin and Azithromycin) are recognized causes of drug-induced hypersensitivity AIN. **NEET-PG High-Yield Pearls:** 1. **Classic Triad of AIN:** Fever, Rash, and Arthralgia (present in only <10–15% of cases). 2. **Laboratory Hallmark:** **Eosinophiluria** (Hansel’s stain) and peripheral eosinophilia. 3. **Gold Standard Diagnosis:** Renal Biopsy (shows interstitial inflammatory infiltrate with eosinophils). 4. **Common Triggers (The 5 P's):** **P**ee (Diuretics), **P**ain-killers (NSAIDs), **P**enicillins/Cephalosporins, **P**PIs (Omeprazole), and **P**ifampicin (Rifampicin).

Q: Which of the following conditions is characterized by these ECG changes?

Hyperkalemia. ***Hyperkalemia*** - Classic ECG changes include **peaked T waves**, **widened QRS complexes**, and **flattened or absent P waves** as potassium levels rise. - Severe hyperkalemia can progress to a **sine wave pattern** on ECG, which is a life-threatening arrhythmia requiring immediate treatment. *Hyponatremia* - **Sodium imbalances** do not produce characteristic or specific ECG changes. - Clinical manifestations are primarily **neurological** (confusion, seizures) rather than cardiac rhythm disturbances. *Hypernatremia* - Like hyponatremia, **elevated sodium levels** do not cause distinctive ECG abnormalities. - Symptoms are mainly **neurological** (altered mental status, hyperreflexia) due to cellular dehydration. *Hypokalemia* - ECG changes include **flattened T waves**, **prominent U waves**, and **ST depression** - opposite to hyperkalemia findings. - May also cause **prolonged QT interval** and increased risk of **torsades de pointes** arrhythmia.

Question 1

All of the following factors are associated with adverse prognosis and high risk of renal progression in Lupus Nephritis, EXCEPT:

Accepted Answer

Anti-LA (SSB)

Answer

High levels of Anti-ds DNA

Answer

Persistent proteinuria (nephrotic range > 3 gm/day)

Answer

Hypocomplementenemia

Question 2

Which of the following is NOT a part of "Triple therapy" immunosuppression for a post-renal transplant patient?

Accepted Answer

Belatacept

Answer

Prednisone

Answer

Cyclosporine

Answer

Azathioprine

Question 3

What does the delta gap compare?

Accepted Answer

Change in anion gap with bicarbonate

Answer

Change in anion gap with chloride only

Answer

Change in anion gap with sodium and potassium

Answer

Change in anion gap with sodium only

Question 4

All of the following antibiotics are known to cause acute interstitial nephritis, except?

Accepted Answer

Aminoglycosides

Answer

Erythromycin

Answer

Sulphonamides

Answer

Ciprofloxacin

Question 5

A 55-year-old man with type II diabetes mellitus, essential hypertension, and ischemic heart disease presents for a routine examination. Laboratory studies reveal a serum potassium of 6 mEq/L. He has no muscle weakness and no ECG changes apart from evidence of a prior inferior wall myocardial infarction. He has mild compensated metabolic acidosis with a normal serum anion gap. Urine examination shows significantly lower than expected potassium excretion despite an elevated serum potassium concentration. Which of the following is most likely to explain the hyperkalemia observed in this patient?

Accepted Answer

Decreased renin secretion

Answer

Decreased insulin secretion

Answer

Increased blood glucose

Answer

Increased BNP secretion

Question 6

Increased anion gap acidosis is seen in which of the following conditions?

Accepted Answer

Diabetic ketoacidosis (DKA), Alcoholic ketoacidosis (AKA), Renal tubular acidosis (RTA), Alcoholic fatty liver disease (AFLD)

Answer

Renal tubular acidosis (RTA), Alcoholic fatty liver disease (AFLD), Organic aciduria

Answer

Alcoholic fatty liver disease (AFLD), Organic aciduria, Diarrhoea

Answer

Diabetic ketoacidosis (DKA), Alcoholic fatty liver disease (AFLD), Diarrhoea

Question 7

Which of the following conditions is characterized by these ECG changes?

Accepted Answer

Hyperkalemia

Answer

Hyponatremia

Answer

Hypernatremia

Answer

Hypokalemia

Question 8

In which one of the following conditions is a renal biopsy contraindicated?

Accepted Answer

Uncontrolled hypertension

Answer

Acute renal failure

Answer

Nephrotic syndrome

Answer

Isolated hematuria

Question 9

Pre-renal azotemia is associated with which of the following characteristic features?

Accepted Answer

Urinary sodium < 10 mmol/L

Answer

Renal failure index > 1

Answer

Urine osmolality < 500 mOsm/kg

Answer

Urinary creatinine/plasma creatinine ratio < 20

Question 10

A patient presents with the following blood biochemical values: Calcium 6 mg/dL; Uric acid 13 mg/dL; Phosphorus 12 mg/dL; Creatinine 6 mg/dL. Which of the following is a possible diagnosis?

Accepted Answer

Uric acid nephropathy

Answer

Krait bite

Answer

Hypercalcemic nephropathy

Answer

Rickets

Nephrology — MCQs

Nephrology — MCQs

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