Kidney Stones and Obstructive Uropathy — MCQs
A patient presents with hypertension and has a history of renal stones, along with several episodes of renal colic. Which diuretic is the most appropriate to use?
A patient presented with complaints of pain in the flank region with hematuria. On investigation, X-ray shows multiple calcification (stones) in both kidneys. What is the probable diagnosis?
What is the first-line intervention for acute symptomatic hydroureter with ureteral obstruction requiring urgent decompression?
Renal stones are seen as a complication by using the following drug:
The most sensitive imaging modality to detect early renal tuberculosis is:
Which of the following types of kidney stones are commonly associated with urinary tract infections?
Acute onset of anuria in elderly men is typically associated with which of the following conditions?
A 30-year-old female presents with sterile pyuria. The radiograph below is provided. What is the most likely diagnosis?
A child presented with intermittent episodes of left sided flank pain. Ultrasonography reveals large hydronephrosis with dilated renal pelvis and cortical thinning with a normal ureter. Kidney differential function was observed to be 19%. Which of the following is the best management?
Interstitial nephritis is common with
Kidney Stones and Obstructive Uropathy Indian Medical PG Practice Questions and MCQs
Question 1: A patient presents with hypertension and has a history of renal stones, along with several episodes of renal colic. Which diuretic is the most appropriate to use?
- A. Furosemide
- B. Hydrochlorothiazide (Correct Answer)
- C. Ethacrynic acid
- D. Spironolactone
- E. Indapamide
Explanation: **Hydrochlorothiazide** - **Thiazide diuretics** like hydrochlorothiazide reduce urinary calcium excretion, which is beneficial in patients with a history of **calcium renal stones**. - This effect helps prevent the recurrence of renal stones while also treating hypertension. - Among thiazide and thiazide-like diuretics, hydrochlorothiazide has the **most established evidence** for preventing calcium stone recurrence. *Furosemide* - Furosemide is a **loop diuretic** that increases urinary calcium excretion, which would exacerbate the risk of renal stone formation. - While effective for hypertension, its effect on calcium makes it unsuitable for this patient. *Ethacrynic acid* - Ethacrynic acid is also a **loop diuretic** with similar effects to furosemide, including increasing urinary calcium excretion. - This makes it an inappropriate choice for a patient with a history of renal stones. *Spironolactone* - Spironolactone is a **potassium-sparing diuretic** that works by antagonizing aldosterone, primarily affecting sodium and potassium excretion. - It does not significantly impact urinary calcium excretion in a way that would prevent calcium renal stones, nor is it a first-line agent for hypertension with co-existing renal stones. *Indapamide* - Indapamide is a **thiazide-like diuretic** with some calcium-retaining properties, but it is less effective than hydrochlorothiazide in reducing calcium excretion. - While it can be used for hypertension, **hydrochlorothiazide is preferred** specifically for preventing calcium stone recurrence due to stronger evidence and greater effect on reducing urinary calcium.
Question 2: A patient presented with complaints of pain in the flank region with hematuria. On investigation, X-ray shows multiple calcification (stones) in both kidneys. What is the probable diagnosis?
- A. Polycystic kidney disease
- B. Parathyroid Adenoma
- C. Renal calculi (Correct Answer)
- D. CKD
Explanation: ***Renal calculi*** - The presence of **flank pain**, **hematuria**, and **multiple calcifications (stones) in both kidneys** on X-ray directly points to a diagnosis of renal calculi (kidney stones) [1]. - These stones can cause pain due to obstruction and irritation, leading to blood in the urine [1]. *Polycystic kidney disease* - This condition is characterized by the development of numerous **cysts in the kidneys**, which are fluid-filled sacs, not calcifications or stones [2]. - While it can cause flank pain and hematuria, the imaging finding of **multiple calcifications** is inconsistent with typical PCKD presentation [2]. *Parathyroid Adenoma* - A parathyroid adenoma leads to **hyperparathyroidism**, which can cause **hypercalcemia** and subsequently increase the risk of **calcium kidney stones** [1]. - However, the diagnosis directly relates to the presence of stones as seen on X-ray, not the underlying cause of stone formation, and the question does not provide enough information to confirm hyperparathyroidism. *CKD* - **Chronic kidney disease (CKD)** is a progressive loss of kidney function over time, representing a *spectrum* of kidney damage. - While kidney stones can lead to CKD, and CKD can present with various symptoms, the direct finding of **multiple calcifications (stones)** on imaging is a specific indicator of renal calculi rather than CKD itself as the primary diagnosis.
Question 3: What is the first-line intervention for acute symptomatic hydroureter with ureteral obstruction requiring urgent decompression?
- A. Antibiotic prophylaxis alone
- B. Immediate ureterolithotomy
- C. Endoscopic ureteral stenting (Correct Answer)
- D. Urinary alkalization
Explanation: ***Endoscopic ureteral stenting*** - **Endoscopic ureteral stenting** is the primary intervention for **acute symptomatic ureteral obstruction** requiring urgent decompression when the obstruction causes **hydroureter**. - This minimally invasive procedure provides immediate drainage from the kidney to the bladder, preventing further renal damage, managing pain, and relieving obstruction. - **Indications for urgent stenting** include: infected hydronephrosis, impaired renal function, intractable pain, solitary kidney with obstruction, or bilateral obstruction. - Alternative to stenting is **percutaneous nephrostomy**, particularly when retrograde stent placement fails or in infected systems. *Antibiotic prophylaxis alone* - While antibiotics are essential when infection complicates obstruction (pyonephrosis), **antibiotics alone cannot relieve the mechanical obstruction**. - The physical blockage must be addressed to prevent progressive renal damage and sepsis. *Immediate ureterolithotomy* - **Open ureterolithotomy** is a definitive surgical treatment but is **not first-line** for acute obstruction. - It is more invasive and typically reserved for failed endoscopic management, large impacted stones, or anatomical abnormalities preventing endoscopic access. - Modern approach favors initial decompression followed by definitive treatment (ureteroscopy, ESWL, or surgery). *Urinary alkalization* - **Urinary alkalization** may help dissolve **uric acid stones** over time but does not provide immediate relief of acute obstruction. - This is an adjunctive measure for specific stone types, not an emergency intervention for symptomatic hydroureter.
Question 4: Renal stones are seen as a complication by using the following drug:
- A. Zonisamide (Correct Answer)
- B. Oxcarbazepine
- C. Phenytoin
- D. Tiagabine
Explanation: ***Zonisamide*** - **Zonisamide** is a sulfonamide derivative that can inhibit **carbonic anhydrase**, leading to metabolic acidosis and increased urinary calcium excretion, which promotes the formation of **kidney stones**. - Patients on zonisamide should be monitored for **renal stone formation** and advised to maintain adequate hydration. *Oxcarbazepine* - **Oxcarbazepine** is an antiepileptic drug known for causing **hyponatremia** and, less commonly, dermatological reactions such as rash. - It is not typically associated with a significant risk of **renal stone formation**. *Phenytoin* - **Phenytoin** is an older antiepileptic drug commonly associated with side effects such as **gingival hyperplasia**, hirsutism, and folate deficiency. - While it has various side effects, **nephrolithiasis** (kidney stones) is not a common or recognized complication. *Tiagabine* - **Tiagabine** is an antiepileptic drug that works by inhibiting GABA reuptake. Its main side effects include dizziness, weakness, and somnolence. - There is no significant evidence to suggest that **tiagabine** causes **renal stone formation**.
Question 5: The most sensitive imaging modality to detect early renal tuberculosis is:
- A. Intravenous urography
- B. Magnetic resonance imaging (Correct Answer)
- C. Ultrasound
- D. Computed tomography
Explanation: ***Magnetic resonance imaging*** - **MRI** is the most sensitive imaging modality for detecting **early renal tuberculosis** due to its superior soft tissue contrast resolution. - It can identify subtle **parenchymal inflammatory changes**, early granulomas, and edema before calcification or cavitation occurs. - MRI is particularly useful for detecting **early renal cortical involvement** and small lesions that may be missed by other modalities. - Provides excellent anatomical detail without ionizing radiation. *Computed tomography* - **CT** is excellent for detecting **established renal tuberculosis** with calcifications, cavitations, and collecting system abnormalities. - However, calcifications and cavitations represent **intermediate to late findings**, not early disease. - CT is less sensitive than MRI for detecting subtle parenchymal inflammatory changes in early stages. - More useful once the disease has progressed to structural changes. *Ultrasound* - **Ultrasound** is useful for screening and follow-up but has significant limitations for early disease detection. - May miss small lesions, subtle parenchymal changes, and early calcifications. - Operator-dependent and limited by **acoustic windows** and patient body habitus. *Intravenous urography* - **IVU** primarily detects changes in the **collecting system** such as strictures, calyceal clubbing, and ureteral abnormalities. - These represent **late manifestations** of renal tuberculosis, not early disease. - Has largely been replaced by cross-sectional imaging (CT/MRI) for evaluating renal pathology. - Less sensitive for parenchymal involvement compared to CT or MRI.
Question 6: Which of the following types of kidney stones are commonly associated with urinary tract infections?
- A. Struvite stones (Correct Answer)
- B. Cystine stones
- C. Xanthine stones
- D. Calcium oxalate stones
Explanation: ***Struvite stones*** - **Struvite stones** (magnesium ammonium phosphate) are strongly associated with **urinary tract infections (UTIs)** caused by urease-producing bacteria like *Proteus* and *Klebsiella*. - These bacteria hydrolyze urea into ammonia and carbon dioxide, increasing urine pH and promoting the precipitation of struvite, often forming **staghorn calculi** [1]. *Cystine stones* - **Cystine stones** are caused by a **genetic defect** in amino acid transport, leading to increased excretion of cystine, ornithine, lysine, and arginine (COLA) in the urine. - They are not directly associated with UTIs but rather with a rare inherited metabolic disorder called **cystinuria**. *Xanthine stones* - **Xanthine stones** are very rare and typically occur in individuals with **xanthinuria**, a genetic disorder characterized by a deficiency in xanthine oxidase. - They are also not linked to UTIs but are a consequence of abnormal purine metabolism. *Calcium oxalate stones* - **Calcium oxalate stones** are the most common type of kidney stone, resulting from high levels of calcium and oxalate in the urine, often due to dietary factors, malabsorption, or idiopathic hypercalciuria. - While UTIs can complicate any kidney stone, **calcium oxalate stones** are not primarily *caused* by UTIs. [1]
Question 7: Acute onset of anuria in elderly men is typically associated with which of the following conditions?
- A. Bilateral infarction of kidneys
- B. Obstructive urinary disease (Correct Answer)
- C. Acute tubular necrosis
- D. Acute cortical necrosis
Explanation: ***Obstructive urinary disease*** - In elderly men, **prostatic enlargement** (benign prostatic hyperplasia or prostate cancer) is a common cause of urinary obstruction, leading to **bilateral hydronephrosis** and anuria [1]. - Anuria in this context is typically acute because the obstruction causes a sudden inability for urine to pass from the kidneys [1]. *Bilateral infarction of kidneys* - This is a rare cause of anuria and usually results from **atheroembolic disease** or other vascular catastrophes. - While it can cause anuria, it is less common than obstructive causes in older men and often presents with more severe **systemic symptoms**. *Acute tubular necrosis* - This typically presents with **oligo-anuria** rather than complete anuria, and often follows an **ischemic or nephrotoxic insult** [2]. - While it can cause significant renal dysfunction, complete anuria for an extended period is less typical compared to obstruction [1]. *Acute cortical necrosis* - This is a rare and severe form of acute kidney injury, often associated with obstetric complications (e.g., **placental abruption**), severe sepsis, or disseminated intravascular coagulation (DIC). - While it causes anuria, it is not typically associated with elderly men as a primary cause compared to obstructive etiologies.
Question 8: A 30-year-old female presents with sterile pyuria. The radiograph below is provided. What is the most likely diagnosis?
- A. Psoas Calcification
- B. Putty Kidney (Correct Answer)
- C. Staghorn calculus
- D. Nephrocalcinosis
Explanation: ***Putty Kidney*** - The image visible in the question shows a **caseous calcification** of the renal parenchyma, which is characteristic of a "putty kidney," a late manifestation of **renal tuberculosis**. - **Sterile pyuria** is commonly associated with renal tuberculosis, where Mycobacterium tuberculosis infection leads to chronic inflammation and granuloma formation in the kidney, eventually resulting in caseous necrosis and calcification. *Psoas Calcification* - This typically refers to calcification within the **psoas muscle**, which would appear as a linear or amorphous calcification along the path of the muscle, an appearance not consistent with the image. - While psoas abscesses can calcify, they would not manifest as widespread renal parenchymal calcification and are not specifically linked to sterile pyuria in this manner. *Staghorn Calculus* - A **staghorn calculus** is a large, branched kidney stone that fills all or part of the renal pelvis and calyces, resembling the antlers of a stag. - While these stones are composed of mineral salts and would be radiopaque, their morphology is distinctly different from the diffuse, caseous calcification seen in the image. *Nephrocalcinosis* - **Nephrocalcinosis** is a condition characterized by diffuse microcalcifications throughout the renal parenchyma, usually affecting the tubules. - The calcifications in the provided image appear more nodular and clustered, consistent with late-stage tuberculous caseous necrosis, rather than the fine, diffuse pattern of nephrocalcinosis.
Question 9: A child presented with intermittent episodes of left sided flank pain. Ultrasonography reveals large hydronephrosis with dilated renal pelvis and cortical thinning with a normal ureter. Kidney differential function was observed to be 19%. Which of the following is the best management?
- A. Endopylostomy
- B. Nephrectomy
- C. Pyeloplasty (Correct Answer)
- D. External drainage
Explanation: ***Pyeloplasty*** - **Pyeloplasty** is the gold standard for treating **ureteropelvic junction (UPJ) obstruction**, which is indicated by hydronephrosis, a dilated renal pelvis, and a normal ureter. - While **19% differential function** is in the borderline range, pyeloplasty is still preferred in **pediatric patients** because: - There is potential for **functional recovery** after relieving obstruction, especially in children - The kidney retains some salvageable function (generally >15% warrants preservation) - The **cortical thinning** suggests chronic obstruction, but intermittent symptoms indicate acute-on-chronic component with potential for improvement - Preserving renal mass is particularly important in children for long-term renal reserve - **Nephrectomy would only be considered if function was <10-15%** or if there were complications like recurrent infections or symptomatic non-functioning kidney. *Endopylostomy* - **Endopylostomy** (endoscopic pyelotomy) is a minimally invasive procedure for UPJ obstruction, but it has a **lower success rate** (70-85%) compared to open or laparoscopic pyeloplasty (>95%). - It is typically considered for **less severe obstructions** or as a secondary option, not for cases with significant hydronephrosis and cortical thinning where a more definitive repair is needed. - The anatomical distortion from severe hydronephrosis makes endoscopic approach less ideal. *Nephrectomy* - **Nephrectomy** (kidney removal) would be considered if the kidney function was **minimal (<10-15%)** or if the kidney was clearly non-salvageable with persistent complications. - With **19% differential function**, there is still meaningful functional reserve worth preserving, especially in a child who may benefit from improved function post-decompression. - Removing a kidney with nearly 20% function would be overly aggressive and deprive the child of potential renal reserve. *External drainage* - **External drainage** (e.g., nephrostomy tube) is a **temporary measure** primarily used for acute decompression of a severely obstructed kidney or to assess renal recovery potential before definitive repair. - It does not address the underlying anatomical obstruction and is not a long-term solution for UPJ obstruction. - While it could be used as a temporizing measure, definitive surgical correction (pyeloplasty) is the appropriate next step.
Question 10: Interstitial nephritis is common with
- A. Black water fever
- B. Rhabdomyolysis
- C. Tumor lysis syndrome
- D. Nonsteroidal anti-inflammatory drugs (NSAIDs) (Correct Answer)
Explanation: ***Nonsteroidal anti-inflammatory drugs (NSAIDs)*** - **NSAIDs** are a known cause of **acute interstitial nephritis** (AIN), an inflammatory condition affecting the tubules and interstitium of the kidney [1]. - This adverse reaction often manifests as **fever**, **rash**, **eosinophilia**, and **acute kidney injury**, typically 7-10 days after drug exposure. *Black water fever* - **Blackwater fever** is a severe complication of **malaria**, characterized by massive hemolysis leading to **hemoglobinuria**, which darkens the urine. - It primarily causes **acute kidney injury** through **acute tubular necrosis** due to hemoglobin precipitation in the renal tubules, not interstitial nephritis. *Rhabdomyolysis* - **Rhabdomyolysis** involves the breakdown of muscle tissue, releasing myoglobin into the bloodstream, which is toxic to the kidneys. [1] - This condition leads to **acute kidney injury** predominantly through **acute tubular necrosis** due to myoglobin casts obstructing tubules and direct toxicity, not interstitial inflammation. *Tumor lysis syndrome* - **Tumor lysis syndrome** occurs when large numbers of cancer cells are rapidly destroyed, releasing intracellular contents like potassium, phosphate, and nucleic acids. - The high concentration of **uric acid** and **phosphate** in the renal tubules leads to crystal formation, causing **acute kidney injury** primarily through **acute uric acid nephropathy** and **phosphate nephropathy**, rather than interstitial nephritis [1].
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