Nephrology Practice Questions

Q: Broad cast is characteristic of which of the following conditions?

Crescentic Glomerulonephritis (CRF). **Explanation:** **Broad casts** (also known as "Renal Failure Casts") are significantly wider than ordinary casts. They are formed in the **large collecting ducts** that have undergone compensatory dilatation due to a severe reduction in the number of functioning nephrons [1]. 1. **Why Option A is Correct:** Broad casts are the hallmark of **Chronic Renal Failure (CRF)**. In chronic kidney disease, as nephrons are lost, the remaining viable nephrons hypertrophy and their collecting ducts dilate to handle the increased solute load [1]. When urinary stasis occurs in these wide ducts, broad casts are formed. While the question lists "Crescentic GN," it is categorized here as a precursor to or a manifestation of rapidly progressing chronic/end-stage renal pathology where nephron loss is extensive. 2. **Why Other Options are Incorrect:** * **Acute Glomerulonephritis (Ac GN):** Characterized primarily by **RBC casts** (dysmorphic RBCs), indicating glomerular inflammation [1]. * **Acute Renal Failure (ARF):** Typically associated with **Muddy Brown (Granular) casts**, which are pathognomonic for Acute Tubular Necrosis (ATN). * **Renal Tuberculosis:** Characterized by **sterile pyuria** (WBCs in urine without bacterial growth on standard culture) and occasionally "pipestem" ureters on imaging, but not specific casts. **NEET-PG High-Yield Pearls:** * **Waxy Casts:** Also seen in CRF; they represent the final stage of granular cast degeneration and indicate extreme chronicity. * **Hyaline Casts:** Most common type; seen in concentrated urine, dehydration, or after vigorous exercise (non-specific). * **Fatty Casts ("Maltese Cross"):** Pathognomonic for **Nephrotic Syndrome**. * **WBC Casts:** Characteristic of **Acute Pyelonephritis** or Tubulointerstitial Nephritis.

Q: Interstitial nephritis associated with uveitis is seen in which of the following?

Autoimmune diseases. **Explanation:** The clinical entity described is **TINU Syndrome (Tubulointerstitial Nephritis and Uveitis)**. It is a rare, systemic **autoimmune** condition characterized by the coexistence of acute interstitial nephritis (AIN) [1] and uveitis (typically bilateral, non-granulomatous, and anterior). **Why Autoimmune is Correct:** TINU is classified as an autoimmune/idiopathic disorder because it involves a T-cell mediated delayed hypersensitivity reaction. It is often associated with specific HLA alleles (like HLA-DRB1*0102). The underlying pathophysiology involves an autoimmune attack on shared antigens found in both the renal tubular cells and the uveal tract of the eye. **Analysis of Incorrect Options:** * **Infections (A):** While infections (e.g., Legionella, Leptospirosis) can cause AIN, they do not typically present with the specific constellation of uveitis seen in TINU. * **Drugs (B):** Drug-induced AIN (caused by NSAIDs, Penicillins, or PPIs) is the most common cause of interstitial nephritis overall [1]. However, drug-induced cases present with systemic features like rash, fever, and eosinophilia [1], rather than uveitis. * **Allergy (D):** Allergic interstitial nephritis is essentially the same as drug-induced AIN. While it involves an immune response, it is a Type I or Type IV hypersensitivity to an external allergen, not a primary autoimmune process targeting the eyes. **NEET-PG High-Yield Pearls:** * **Demographics:** TINU is most common in adolescent girls and young women. * **Clinical Presentation:** Renal symptoms (elevated creatinine, sterile pyuria) usually precede or occur simultaneously with ocular symptoms (eye pain, redness, photophobia). * **Diagnosis:** Definitive diagnosis of the renal component requires a **Kidney Biopsy** showing interstitial edema and mononuclear cell infiltration [1]. * **Treatment:** Systemic corticosteroids are the mainstay of treatment for both the nephritis and the uveitis.

Q: All are features of Acute Renal Failure (ARF) except?

Hypertension. Explanation Acute Renal Failure (ARF), now more commonly referred to as Acute Kidney Injury (AKI), is characterized by a sudden decline in GFR leading to the accumulation of nitrogenous waste products [1]. Why Hypertension is the Correct Answer (The "Except"): Hypertension is not a defining feature or a common cause of ARF. In fact, Hypotension (Option A) is a hallmark of pre-renal AKI, the most common type of ARF [1]. While hypertension can occur in specific cases like acute glomerulonephritis or volume overload [1], it is generally a feature of Chronic Kidney Disease (CKD) due to long-standing renin-angiotensin activation and structural vascular changes. In the acute setting, the primary hemodynamic driver is often decreased perfusion (hypotension). Analysis of Other Options: * Metabolic Acidosis (Option B): In ARF, the kidneys fail to excrete fixed acids (like phosphates and sulfates) and cannot regenerate bicarbonate, leading to a high anion gap metabolic acidosis. * Hyperkalemia (Option C): This is the most life-threatening electrolyte abnormality in ARF [1]. Reduced GFR leads to decreased potassium excretion, often exacerbated by metabolic acidosis (which shifts K+ out of cells). High-Yield Clinical Pearls for NEET-PG: * Most common cause of ARF: Pre-renal azotemia (due to hypovolemia/hypotension) [1]. * Most common cause of Intra-renal ARF: Acute Tubular Necrosis (ATN). * Indications for Urgent Dialysis (AEIOU): Acidosis (refractory), Electrolytes (Hyperkalemia >6.5), Ingestion (toxins), Overload (pulmonary edema), Uremia (pericarditis/encephalopathy). * Fractional Excretion of Sodium (FeNa): 2% in ATN.

Q: Which of the following criteria is included in the definition of Acute Kidney Injury?

50% increase in baseline serum creatinine in a week. The definition of **Acute Kidney Injury (AKI)** is standardized globally by the **KDIGO (Kidney Disease: Improving Global Outcomes)** criteria. AKI is defined by a rapid decline in renal function, characterized by specific changes in serum creatinine (SCr) or urine output [1]. ### Why Option D is Correct According to KDIGO, AKI is diagnosed if any of the following occur: 1. **Increase in SCr by ≥0.3 mg/dL** within 48 hours. 2. **Increase in SCr to ≥1.5 times baseline** (a 50% increase) within the last 7 days [1]. 3. **Urine output 20:1 suggests **Prerenal Azotemia** (due to increased urea reabsorption), but it is a diagnostic clue for the *cause* of AKI, not part of the formal definition. * **Option C:** "Urine output <1000 mL/day" is not a criterion. **Oliguria** is defined as <400 mL/day, and **Anuria** as <100 mL/day. AKI criteria use weight-based hourly output (<0.5 mL/kg/h). ### High-Yield NEET-PG Pearls * **Staging:** KDIGO Stage 3 (Failure) is defined by a 3-fold increase in SCr, SCr ≥4.0 mg/dL, or the initiation of Renal Replacement Therapy (RRT). * **Earliest Marker:** Urine output usually drops before SCr rises. * **New Biomarkers:** For exams, remember **NGAL** (Neutrophil Gelatinase-Associated Lipocalin) and **KIM-1** (Kidney Injury Molecule-1) are early markers of tubular damage, often rising before creatinine.

Q: RBC casts are seen in all the following conditions except:

Diabetic nephropathy. The presence of **RBC casts** in urine is a pathognomonic sign of **glomerular hematuria**, indicating an active inflammatory process within the glomerulus (Glomerulonephritis). [1] **1. Why Diabetic Nephropathy is the correct answer:** Diabetic nephropathy is a **non-inflammatory** glomerular disease characterized by basement membrane thickening and mesangial expansion (Kimmelstiel-Wilson nodules). [1] It typically presents with progressive proteinuria and a "bland" urinary sediment. While microscopic hematuria can occasionally occur, the formation of RBC casts is not a feature of this condition. **2. Analysis of Incorrect Options:** * **Wegener’s Granulomatosis (GPA):** This is a small-vessel vasculitis that causes **Pauci-immune Crescentic Glomerulonephritis**. [1] The intense glomerular inflammation leads to the leakage of RBCs into the nephron, forming casts. * **Systemic Lupus Erythematosus (SLE):** Lupus nephritis (especially Classes III and IV) involves immune complex deposition and severe glomerular inflammation, frequently resulting in RBC casts. [1] * **Infective Endocarditis:** This can cause **post-infectious glomerulonephritis** or embolic phenomena, leading to an active nephritic sediment containing RBC casts. [2] **Clinical Pearls for NEET-PG:** * **RBC Casts = Nephritic Syndrome:** Always look for these in cases of Post-Streptococcal GN (PSGN), Goodpasture syndrome, and Alport syndrome. [1], [2] * **Dysmorphic RBCs:** Like RBC casts, acanthocytes (mickey-mouse shaped RBCs) suggest a glomerular origin of bleeding. * **Bland Sediment:** Seen in Diabetic Nephropathy and Amyloidosis (mostly proteinuria). * **Fatty Casts/Maltese Cross:** Pathognomonic for **Nephrotic Syndrome**. * **Muddy Brown Casts:** Pathognomonic for **Acute Tubular Necrosis (ATN)**.

Question 1

All of the following are seen in patients with acute renal failure, EXCEPT?

Accepted Answer

Acute uric acid nephropathy with hyperkalemia

Answer

Hypocalcemia

Answer

Hyperphosphatemia

Answer

Increased body weight

Question 2

Broad cast is characteristic of which of the following conditions?

Accepted Answer

Crescentic Glomerulonephritis (CRF)

Answer

Acute Glomerulonephritis (Ac GN)

Answer

Acute Renal Failure (ARF)

Answer

Renal Tuberculosis (Renal TB)

Question 3

Interstitial nephritis associated with uveitis is seen in which of the following?

Accepted Answer

Autoimmune diseases

Answer

Infections

Answer

Drugs

Answer

Allergy

Question 4

Serum C3 is persistently low in which of the following conditions?

Accepted Answer

Lupus nephritis

Answer

Post-streptococcal glomerulonephritis

Answer

Membranoproliferative glomerulonephritis

Answer

Glomerulonephritis related to bacterial endocarditis

Question 5

A 19-year-old man presents with hemoptysis and decreased urine output. Physical examination reveals normal lung and heart sounds, with no skin rash, palpable lymph nodes, or abdominal abnormalities. Chest X-ray shows bilateral lower lobe infiltrates, and his creatinine is elevated. Urinalysis is positive for red blood cells and protein. A renal biopsy reveals autoantibodies to basement membranes. Which of the following is the most likely diagnosis?

Accepted Answer

Goodpasture syndrome

Answer

Thyroiditis

Answer

Myasthenia gravis

Answer

Thrombocytopenia

Question 6

All are features of Acute Renal Failure (ARF) except?

Accepted Answer

Hypertension

Answer

Hypotension

Answer

Metabolic acidosis

Answer

Hyperkalemia

Question 7

Which of the following criteria is included in the definition of Acute Kidney Injury?

Accepted Answer

50% increase in baseline serum creatinine in a week

Answer

Increase of serum creatinine by 1 mg/dL in 24 hours

Answer

BUN/Creatinine ratio above 20

Answer

Urine output less than 1000 mL in a day

Question 8

Which of the following causes Nephrogenic Diabetes Insipidus?

Accepted Answer

Sheehan's syndrome

Answer

Amyloidosis

Answer

Polycystic kidney Disease

Answer

Lithium

Question 9

Uremic lung most often results due to –

Accepted Answer

Pulmonary edema

Answer

Fibrosis

Answer

Alveolar injury

Answer

Congestive cardiac liver

Question 10

RBC casts are seen in all the following conditions except:

Accepted Answer

Diabetic nephropathy

Answer

Wegener's granulomatosis

Answer

Systemic lupus erythematosus (SLE)

Answer

Infective endocarditis

Nephrology — MCQs

Nephrology — MCQs

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