Contrast-Induced Nephropathy — MCQs
An 8-year-old child presents with hematuria 5 days after a throat infection. What is the most likely diagnosis?
Which of the following contrast agents is PREFERRED in a patient with renal dysfunction for the prevention of contrast-induced nephropathy?
Which of the following is Iso-osmolar agent?
The most appropriate investigation to diagnose and determine the extent of renal injury in a 15-year-old boy who presents with hematuria and left-sided abdominal pain 48 hours after sustaining a blunt abdominal injury, with a pulse rate of 96/minute, blood pressure of 110/70 mmHg, hemoglobin of 10.8 gm%, and packed cell volume of 31%, would be-
A dense persistent nephrogram may be seen in all of the following except:
A child presents with brown colored urine and oliguria for last 3 days. He has mild facial and pedal edema. His blood pressure is 126/90. He has +3 proteinuria with 100 red cell and a few granular casts. His creatinine is 0.9, urea is 56. What is his diagnosis?
Uremic complications typically arise during which of the following phases of renal failure?
Which among the following is the BEST irrigating fluid during ECCE?
Excretory urography is contraindicated in:
Causes of thickened gallbladder wall on ultrasound examination are all except:
Contrast-Induced Nephropathy Indian Medical PG Practice Questions and MCQs
Question 1: An 8-year-old child presents with hematuria 5 days after a throat infection. What is the most likely diagnosis?
- A. Nephrotic syndrome
- B. Ig A nephropathy (Correct Answer)
- C. Post streptococcal nephropathy
- D. Hereditary nephritis (Alport syndrome)
Explanation: ***Ig A nephropathy*** - This condition is characterized by **hematuria** that typically occurs within days (1-5 days) of an **upper respiratory tract infection**. - The rapid onset of symptoms after infection is a key differentiator from post-streptococcal glomerulonephritis. *Nephrotic syndrome* - This syndrome is defined by **massive proteinuria**, **hypoalbuminemia**, **edema**, and **hyperlipidemia**, not primarily by gross hematuria following an infection. - While some forms of nephrotic syndrome can cause hematuria, the prominent feature here is the timing after a throat infection and gross hematuria. *Post streptococcal nephropathy* - This condition typically presents with **hematuria** 7-21 days after a Streptococcus infection, a longer latency period than described here. - It often involves a decline in renal function, hypertension, and edema, which are not the primary focus of the vignette's timing. *Hereditary nephritis (Alport syndrome)* - This is a genetic disorder causing progressive renal failure, **sensorineural hearing loss**, and ocular abnormalities. - While it causes hematuria, it is typically chronic and not acutely triggered by a throat infection in a specific timeframe as described.
Question 2: Which of the following contrast agents is PREFERRED in a patient with renal dysfunction for the prevention of contrast-induced nephropathy?
- A. Iso-osmolar contrast (Correct Answer)
- B. High osmolar contrast
- C. Ionic contrast
- D. Low osmolar contrast
Explanation: ***Iso-osmolar contrast*** - **Iso-osmolar contrast agents** (e.g., iodixanol) have an osmolality of ~290 mOsm/kg, which is identical to that of plasma. - **This is the PREFERRED choice** in patients with renal dysfunction as multiple studies demonstrate the lowest risk of contrast-induced nephropathy (CIN). - The iso-osmolar formulation minimizes osmotic stress on renal tubules and reduces the risk of acute kidney injury. - **Current guidelines recommend iso-osmolar agents as first-line** in high-risk patients with pre-existing renal impairment. *Low osmolar contrast* - **Low osmolar contrast agents** have osmolality of 600-900 mOsm/kg, which is significantly lower than high osmolar agents but still 2-3 times higher than plasma. - While **acceptable and safer than high osmolar agents**, they are not as optimal as iso-osmolar contrast for patients with renal dysfunction. - These agents are widely used and represent a reasonable alternative when iso-osmolar agents are not available. *High osmolar contrast* - **High osmolar contrast agents** have osmolality >1400 mOsm/kg (about 5 times that of plasma). - They carry the **highest risk of contrast-induced nephropathy** due to severe osmotic load and direct tubular toxicity. - **Contraindicated or strongly avoided** in patients with pre-existing renal dysfunction. *Ionic contrast* - **Ionic contrast** refers to the chemical structure (dissociates into ions) rather than osmolality. - Can be either high or low osmolar—the ionic nature alone does not determine renal safety. - The critical factor for nephrotoxicity prevention is osmolality, not ionic charge.
Question 3: Which of the following is Iso-osmolar agent?
- A. Non-ionic Dimer contrast media (Correct Answer)
- B. Ionic Monomer - High osmolality contrast media
- C. Non-ionic Monomer - Low osmolality contrast media
- D. Ionic Dimer - Low osmolality contrast media
Explanation: ***Non-ionic Dimer contrast media*** - **Iodixanol** is the only available non-ionic dimer contrast agent, and it is **iso-osmolar** with blood plasma (290 mOsm/kg). - Its iso-osmolality contributes to a lower incidence of adverse reactions, particularly in patients at high risk. *Ionic Monomer - High osmolality contrast media* - These agents have an osmolality significantly higher than that of blood plasma, often 6-8 times greater. - High osmolality leads to a higher incidence of adverse effects due to cellular fluid shifts and direct endothelial damage. *Non-ionic Monomer - Low osmolality contrast media* - These agents have an osmolality lower than ionic monomers but are still hyperosmolar compared to blood plasma (typically 2-3 times higher). - While generally safer than high-osmolality agents, they can still cause discomfort and adverse reactions due to their hyperosmolality. *Ionic Dimer - Low osmolality contrast media* - Ionic dimers, such as **ioxaglate**, are considered low-osmolality agents but are still hyperosmolar relative to plasma. - They feature two benzene rings with iodine atoms and are salts, contributing to their osmolality.
Question 4: The most appropriate investigation to diagnose and determine the extent of renal injury in a 15-year-old boy who presents with hematuria and left-sided abdominal pain 48 hours after sustaining a blunt abdominal injury, with a pulse rate of 96/minute, blood pressure of 110/70 mmHg, hemoglobin of 10.8 gm%, and packed cell volume of 31%, would be-
- A. Sonographic evaluation of abdomen
- B. Intravenous pyelography
- C. Contrast enhanced computed tomography (Correct Answer)
- D. MR urography
Explanation: ***Contrast enhanced computed tomography*** - **CT with intravenous contrast** is the gold standard for evaluating **renal trauma**, providing detailed anatomical information on the extent of injury, including lacerations, hematomas, and urinary extravasation, which might be missed by other modalities. - It rapidly assesses the **parenchyma**, **collecting system**, and surrounding structures, allowing for proper staging of the injury and guiding management decisions. *Sonographic evaluation of abdomen* - **Ultrasound** is useful for rapidly detecting **free fluid** (e.g., blood) in the abdomen and assessing major organ integrity, but its ability to characterize renal parenchymal injuries or urinary extravasation is limited. - It is **operator-dependent** and often insufficient for detailed staging of renal trauma compared to CT. *Intravenous pyelography* - **IVP** primarily evaluates the **collecting system** and ureteral patency but has limited sensitivity for assessing renal parenchymal injuries or perinephric hematomas. - It involves radiation exposure and a contrast load, and generally provides **less anatomical detail** than modern CT scans. *MR urography* - **MR urography** provides excellent soft tissue contrast without ionizing radiation, but it is typically **less readily available** in an emergency setting and takes longer to perform than CT. - Its role in acute trauma is usually reserved for cases where **iodinated contrast is contraindicated** (e.g., severe allergy, renal insufficiency) or when specific soft-tissue detail is crucial for follow-up.
Question 5: A dense persistent nephrogram may be seen in all of the following except:
- A. Severe hydronephrosis
- B. Dehydration
- C. Acute ureteral obstruction
- D. Systemic hypertension (Correct Answer)
Explanation: ***Systemic hypertension*** - **Systemic hypertension** is not typically associated with a dense, persistent nephrogram on imaging. While chronic hypertension can cause renal damage, it does not directly lead to the characteristic prolonged parenchymal enhancement. - A dense, persistent nephrogram suggests impaired contrast excretion or increased reabsorption, neither of which is a primary manifestation of systemic hypertension itself. *Severe hydronephrosis* - **Severe hydronephrosis** leads to impaired urine flow and delayed transit of contrast medium through the renal tubules, resulting in a persistent nephrogram. - The dilated collecting system and compressed parenchyma can retain contrast for an extended period due to reduced glomerular filtration rate (GFR) in the affected kidney. *Dehydration* - In cases of **dehydration**, the kidneys attempt to conserve water, leading to increased reabsorption of water from the renal tubules. - This process can concentrate the contrast medium within the tubules, resulting in a denser and more persistent nephrogram as it slowly transits through the kidney. *Acute ureteral obstruction* - **Acute ureteral obstruction** causes a build-up of pressure within the renal collecting system, impairing glomerular filtration and slowing the passage of contrast. - The contrast medium remains within the renal parenchyma for a prolonged period due to the blockage, leading to a dense and persistent nephrogram and delayed excretion.
Question 6: A child presents with brown colored urine and oliguria for last 3 days. He has mild facial and pedal edema. His blood pressure is 126/90. He has +3 proteinuria with 100 red cell and a few granular casts. His creatinine is 0.9, urea is 56. What is his diagnosis?
- A. PSGN (Correct Answer)
- B. FSGS
- C. IgA Nephropathy
- D. Nephrolithiasis
Explanation: ***PSGN*** - The presentation with **brown urine**, **oliguria**, **edema**, **hypertension**, and **hematuria with red cell casts** is classic for an acute nephritic syndrome. - Given the patient is a child, and the constellation of symptoms including **sudden onset**, **significant hypertension**, and **granular casts**, **Post-Streptococcal Glomerulonephritis (PSGN)** is the most likely diagnosis. - PSGN typically follows streptococcal pharyngitis or skin infection by 1-3 weeks and presents with acute nephritic syndrome. *FSGS* - **Focal Segmental Glomerulosclerosis (FSGS)** typically presents with **nephrotic syndrome** (heavy proteinuria, hypoalbuminemia, severe edema), not primarily with nephritic features. - While it can cause proteinuria, the presence of **red cell casts** and significant hematuria with acute hypertension points to an inflammatory glomerulonephritis, not FSGS. *IgA Nephropathy* - **IgA Nephropathy (Berger's disease)** can also cause nephritic syndrome in children with hematuria and RBC casts. - However, it typically presents with **recurrent episodes of gross hematuria** occurring **during or immediately after** upper respiratory infections (synpharyngitic hematuria), rather than the delayed presentation seen here. - It usually has a more chronic course with less prominent edema and hypertension compared to PSGN. *Nephrolithiasis* - **Nephrolithiasis (kidney stones)** would typically present with **colicky flank pain** and hematuria. - It would not explain the prominent **edema**, **hypertension**, **significant proteinuria**, or presence of **red cell casts** seen in this patient.
Question 7: Uremic complications typically arise during which of the following phases of renal failure?
- A. Initiation
- B. Maintenance (Correct Answer)
- C. Diuretic Phase
- D. Recovery Phase
Explanation: ***Maintenance*** - During the **maintenance phase**, renal function is severely impaired, leading to the accumulation of **uremic toxins** and metabolic waste products. - This prolonged period of reduced kidney function is when **uremic complications** such as pericarditis, encephalopathy, and coagulopathy typically manifest. *Initiation* - The **initiation phase** is characterized by the initial insult to the kidneys and the onset of reduced glomerular filtration, but significant uremic complications are usually not yet apparent. - It is a period of evolving injury, and the body's compensatory mechanisms may still be able to mitigate acute toxicity. *Diuretic Phase* - The **diuretic phase** is a period of gradual improvement from renal failure, where urine output increases, but the kidneys may still have impaired ability to concentrate urine or fully excrete waste. - While electrolyte imbalances can occur, severe uremic complications are less common as renal function starts to recover. *Recovery Phase* - In the **recovery phase**, renal function gradually normalizes, and the kidneys regain their ability to excrete waste products effectively. - Uremic complications would typically be resolving, not arising, during this phase as **renal repair** takes place.
Question 8: Which among the following is the BEST irrigating fluid during ECCE?
- A. Ringer lactate
- B. Normal saline
- C. Balanced salt solution
- D. Balanced salt solution + glutathione (Correct Answer)
Explanation: ***Balanced salt solution + glutathione*** - **Balanced salt solution with glutathione** is considered the best irrigating fluid for ECCE because it closely mimics the **natural aqueous humor**, maintaining corneal endothelial cell health and viability during surgery. - The addition of **glutathione** provides an antioxidant effect, protecting the corneal endothelium from oxidative stress and maintaining its metabolic function during prolonged irrigation. *Ringer lactate* - While **Ringer's lactate** is a balanced electrolyte solution, it lacks the specific components and buffering capacity present in specialized ophthalmic irrigating solutions. - It does not contain **glutathione** or other agents crucial for maintaining corneal endothelial viability and function during intraocular surgery. *Normal saline* - **Normal saline (0.9% NaCl)** lacks essential ions (calcium, magnesium, potassium) and appropriate pH buffering required for intraocular use. - Its use can lead to **corneal edema** and endothelial cell damage due to ionic imbalance and the absence of protective components found in balanced salt solutions. *Balanced salt solution* - A **plain balanced salt solution (BSS)** is a significant improvement over normal saline or Ringer's lactate as it is physiologically balanced for intraocular use, containing essential electrolytes. - However, it lacks the **antioxidant properties of glutathione**, which provides superior protection to corneal endothelial cells during extended surgical procedures.
Question 9: Excretory urography is contraindicated in:
- A. Single kidney
- B. Trauma
- C. Multiple myeloma (Correct Answer)
- D. Renal artery hypertension
Explanation: ***Multiple myeloma*** - Patients with **multiple myeloma** are at high risk of developing **contrast-induced nephropathy** due to the precipitation of Bence Jones proteins in renal tubules when exposed to iodinated contrast agents. - This can lead to **acute kidney injury** or worsening of pre-existing renal impairment, making excretory urography generally contraindicated. *Single kidney* - While careful consideration is needed, having a **single kidney** does not inherently contraindicate excretory urography if renal function is good. - The primary concern is protecting the remaining kidney from **contrast-induced nephropathy** in patients with pre-existing renal dysfunction, not the number of kidneys. *Trauma* - In cases of **renal trauma**, excretory urography (or more commonly, CT urography) can be used to assess the extent of injury and integrity of the urinary tract. - It is often indicated to evaluate **hematuria** or suspected kidney damage, not contraindicated. *Renal artery hypertension* - Excretory urography was historically used to evaluate for **renal artery stenosis**, a cause of **renal artery hypertension**, by looking for delayed contrast excretion or kidney size differences. - While it has largely been replaced by more modern imaging like CT angiography or MRA, it is not considered a contraindication and can provide some diagnostic information.
Question 10: Causes of thickened gallbladder wall on ultrasound examination are all except:
- A. Congestive cardiac failure
- B. Postprandial state
- C. Kawasaki disease (Correct Answer)
- D. Cholecystitis
Explanation: ***Kawasaki disease*** (Correct Answer) - While Kawasaki disease can cause **gallbladder hydrops** (distension with bile), the primary ultrasound finding is an **enlarged, distended gallbladder** rather than isolated wall thickening. - When gallbladder involvement occurs in Kawasaki disease, it manifests as **acalculous cholecystitis** with hydrops, but this is **not a typical or common presentation** compared to the other causes listed. - The hallmark features of Kawasaki disease are **coronary artery aneurysms** and systemic vasculitis, not primary gallbladder pathology. - In clinical practice, gallbladder wall thickening would **not be attributed to Kawasaki disease** as a primary differential diagnosis. *Incorrect: Congestive cardiac failure* - **Systemic fluid overload** and venous congestion in CHF leads to gallbladder wall thickening due to **transudative edema**. - This is a **common cause** of non-inflammatory gallbladder wall thickening (>3mm). - The wall appears thickened, hypoechoic, and **edematous** without pericholecystic fluid. *Incorrect: Postprandial state* - After eating, the gallbladder **contracts to release bile**, causing the wall to appear thicker on ultrasound due to **accordion-like folding** of the mucosa. - This is a **normal physiological finding** and typically resolves within 1-2 hours. - Scanning should ideally be done after **6-8 hours of fasting** to avoid this pseudo-thickening. *Incorrect: Cholecystitis* - **Acute cholecystitis** is the **classic cause** of gallbladder wall thickening (>3mm, often >5mm). - Associated findings include **gallstones, pericholecystic fluid, positive sonographic Murphy's sign**, and wall edema. - The wall shows **layering** (subserosal edema) and hyperemia on Doppler imaging.
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