Urinary Tract Obstruction and Stones — MCQs
A young patient presents to the OPD with recurrent colicky abdominal pain. Urine examination shows the presence of red blood cells (RBCs) and the following crystal shape in the figure. What is the most likely diagnosis?
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?
Which of the following is typically seen on ultrasound in acute pyelonephritis?
Investigation of choice in small renal calculi is:
A 45-year-old Caucasian male with a history of chronic myeloid leukemia for which he is receiving chemotherapy presents to the emergency room with oliguria and colicky left flank pain. His serum creatinine is 3.0 mg/dL and his urine pH is 5.0. You diagnose nephrolithiasis. His kidney stones, however, are not visible on abdominal x-ray. His stone is most likely composed of which of the following?
Which of the following types of kidney stones are commonly associated with urinary tract infections?
Causes of retention of urine in reproductive age group: a) Cervical fibroid b) Retroverted gravid uterus c) Unilateral hydronephrosis d) Severe UTI e) Posterior urethral valve
Struvite stones are primarily composed of which metal?
All of the following are true about xanthogranulomatous pyelonephritis except which of the following?
Ectopic ureter may be frequently associated with which of the following conditions?
Urinary Tract Obstruction and Stones Indian Medical PG Practice Questions and MCQs
Question 1: A young patient presents to the OPD with recurrent colicky abdominal pain. Urine examination shows the presence of red blood cells (RBCs) and the following crystal shape in the figure. What is the most likely diagnosis?
- A. Cystine stone (Correct Answer)
- B. Glomerulonephritis
- C. Oxalate stone
- D. Polycystic kidney disease
- E. Uric acid stone
Explanation: ***Cystine stone*** - The image displays classic **hexagonal** crystals, which are pathognomonic for **cystine stones**. - Recurrent colicky abdominal pain in a young patient with hematuria (RBCs in urine) is highly suggestive of **nephrolithiasis** (kidney stones), and the crystal morphology confirms cystine as the cause. - Cystine stones are associated with **cystinuria**, an autosomal recessive disorder causing defective renal tubular reabsorption of cystine. *Glomerulonephritis* - While glomerulonephritis can cause hematuria, the presence of **hexagonal crystals** in the urine is not a feature of this condition. - Glomerulonephritis typically involves **dysmorphic RBCs** and **RBC casts** in the urine, not hexagonal crystals. *Oxalate stone* - **Calcium oxalate crystals** typically appear as **envelope-shaped (dihydrate)** or **dumbbell-shaped (monohydrate)**. - While oxalate stones are the most common cause of kidney stones and colicky pain, their crystal morphology is distinct from the hexagonal shape seen here. *Polycystic kidney disease* - Polycystic kidney disease is a genetic disorder characterized by **multiple cysts** in the kidneys, which can cause pain and hematuria. - However, it does **not** typically present with specific crystal shapes like those shown in the image, as the primary pathology is structural, not related to crystal formation. *Uric acid stone* - **Uric acid crystals** typically appear as **rhomboid or diamond-shaped** crystals, often with a yellow-brown color. - While uric acid stones can cause similar symptoms (colicky pain, hematuria), the crystal morphology is distinctly different from the hexagonal cystine crystals shown in the image. - Uric acid stones are associated with **hyperuricemia**, **low urine pH**, and conditions like gout.
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: Which of the following is typically seen on ultrasound in acute pyelonephritis?
- A. Decreased vascularity
- B. Enlarged kidney with diffuse swelling (Correct Answer)
- C. Localized hypoechogenic areas in the kidney
- D. Fluid collection around the kidney
Explanation: ***Enlarged kidney with diffuse swelling*** - In **acute pyelonephritis**, the **most consistent ultrasound finding** is **renal enlargement** with **diffuse swelling** of the affected kidney. - This occurs due to **inflammatory edema** and increased fluid content within the renal parenchyma, representing the body's inflammatory response to infection. - **Diffuse enlargement** is present in the majority of cases and is often the **earliest sonographic manifestation**, making it the most typical finding. *Localized hypoechogenic areas in the kidney* - **Focal or multifocal hypoechoic areas** are indeed **highly characteristic** of acute pyelonephritis and represent zones of **parenchymal edema and inflammation**. - These are seen in approximately **20-80% of cases** and are considered a hallmark feature. - However, they may not be present in all cases, particularly in early or mild disease, whereas **renal enlargement is more consistently present**. - When visible, these areas have high specificity for the diagnosis. *Fluid collection around the kidney* - **Perinephric fluid collections** or abscesses indicate **complicated pyelonephritis** with extension of infection beyond the renal capsule. - These are **not typical findings in uncomplicated acute pyelonephritis** and suggest more severe or advanced infection requiring aggressive management. *Decreased vascularity* - Acute pyelonephritis typically shows **increased vascularity** on color Doppler due to **hyperemia and inflammatory vasodilation**. - **Decreased vascularity** is associated with **renal infarction**, severe ischemia, or chronic scarring—not acute bacterial infection.
Question 4: Investigation of choice in small renal calculi is:
- A. Low dose non enhanced CT (Correct Answer)
- B. High dose non enhanced CT
- C. Low dose enhanced CT
- D. High dose enhanced CT
Explanation: ***Low dose non enhanced CT*** - **Low dose non-enhanced CT (LD-NCCT)** is the investigation of choice for suspected renal calculi, including **small stones as small as 1-2 mm**, due to its **high sensitivity (95-100%) and specificity (94-96%)** for detecting stones. - **Non-contrast** is preferred because contrast material can obscure small stones, and stones themselves are intrinsically dense enough to be visualized without it. - Low-dose protocols reduce radiation exposure by **50-75%** compared to standard CT while maintaining excellent diagnostic accuracy for stone detection. *High dose non enhanced CT* - A **high dose non-enhanced CT** is unnecessary as the diagnostic accuracy for renal calculi is already excellent with a low-dose protocol. - Using a high dose would lead to **increased radiation exposure** to the patient without providing additional diagnostic benefits for stone detection. - Modern low-dose protocols achieve similar image quality for stone identification. *Low dose enhanced CT* - **Enhanced CT** involves the administration of intravenous contrast, which is generally not required for the detection of renal calculi. - Contrast can potentially **obscure small stones** by making them less conspicuous against the enhanced renal parenchyma and collecting system. - It adds risks associated with contrast administration, such as allergic reactions or contrast-induced nephropathy, without improving stone detection. *High dose enhanced CT* - **High dose enhanced CT** combines the disadvantages of both high radiation exposure and contrast material. - This approach is not indicated for renal calculi and would expose the patient to **unnecessary risks and radiation** without improving diagnostic yield for stones. - Contrast is reserved for evaluating complications or alternative diagnoses, not primary stone detection.
Question 5: A 45-year-old Caucasian male with a history of chronic myeloid leukemia for which he is receiving chemotherapy presents to the emergency room with oliguria and colicky left flank pain. His serum creatinine is 3.0 mg/dL and his urine pH is 5.0. You diagnose nephrolithiasis. His kidney stones, however, are not visible on abdominal x-ray. His stone is most likely composed of which of the following?
- A. Uric acid (Correct Answer)
- B. Cystine
- C. Calcium phosphate
- D. Magnesium ammonium phosphate
- E. Calcium oxalate
Explanation: ***Uric acid*** - The patient has **chronic myeloid leukemia (CML)** and is receiving **chemotherapy**, which can cause a rapid turnover of cells, leading to **hyperuricemia** and the formation of uric acid stones. - Uric acid stones are **radiolucent** (not visible on X-ray) and are associated with a **low urine pH** (5.0 in this case). *Cystine* - Cystine stones are caused by a **genetic defect** in amino acid transport, leading to high urinary cystine levels. - While they are also **radiolucent**, there is no clinical information to suggest a genetic predisposition for cystinuria in this patient. *Calcium phosphate* - Calcium phosphate stones are typically **radio-opaque** and usually form in alkaline urine, which contradicts the patient's low urine pH [1]. - They are often associated with conditions like **renal tubular acidosis** or hyperparathyroidism [1]. *Magnesium ammonium phosphate* - These are also known as **struvite stones** and are highly suggestive of **urinary tract infections** with urea-splitting organisms (e.g., *Proteus*) [1]. - They tend to grow large, form **staghorn calculi**, and are **radio-opaque** [1]. *Calcium oxalate* - Calcium oxalate stones are the **most common type** of kidney stone and are **radio-opaque**, making them visible on X-ray. - They are typically associated with conditions causing **hypercalciuria** or hyperoxaluria, which are not explicitly indicated here, and they would be visible on the X-ray.
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: Causes of retention of urine in reproductive age group: a) Cervical fibroid b) Retroverted gravid uterus c) Unilateral hydronephrosis d) Severe UTI e) Posterior urethral valve
- A. ACD
- B. BCD
- C. ABC
- D. ABD (Correct Answer)
Explanation: ***Correct: ABD*** - **Cervical fibroid** and **retroverted gravid uterus** can cause extrinsic compression of the urethra or bladder neck, leading to **urinary retention** in women of reproductive age. - **Severe UTI** can cause bladder inflammation and dysfunction, manifesting as acute urinary retention. *Incorrect: ACD* - This option incorrectly includes **unilateral hydronephrosis** as a direct cause of urinary retention. - Unilateral hydronephrosis is typically due to an obstruction higher up in one ureter and does not directly obstruct bladder emptying, though bilateral hydronephrosis *could* occur with lower urinary tract obstruction. *Incorrect: BCD* - This option correctly identifies **retroverted gravid uterus** and **severe UTI** as causes but incorrectly includes **unilateral hydronephrosis**. - It also omits **cervical fibroid**, which is a significant cause of retention in this demographic. *Incorrect: ABC* - This option incorrectly includes **unilateral hydronephrosis**. - Unilateral hydronephrosis affects the upper urinary tract (kidney/ureter) and does not cause bladder outlet obstruction or urinary retention. **Key Points:** - **Cervical fibroid**: Causes mechanical urethral/bladder neck compression - **Retroverted gravid uterus**: Classic cause in 2nd trimester (12-16 weeks) when incarcerated uterus compresses urethra - **Severe UTI**: Causes retention via bladder inflammation, edema, and detrusor dysfunction - **Unilateral hydronephrosis**: Upper urinary tract issue, NOT a cause of urinary retention - **Posterior urethral valve**: Congenital male condition, irrelevant to reproductive age women
Question 8: Struvite stones are primarily composed of which metal?
- A. Magnesium (Correct Answer)
- B. Calcium
- C. Sodium
- D. Potassium
Explanation: ***Magnesium*** - **Struvite stones** are primarily composed of **magnesium ammonium phosphate**, formed in the presence of urease-producing bacteria. - The presence of magnesium is a defining component of these **infection-related stones**. *Calcium* - **Calcium** is the primary component of the most common type of kidney stones, **calcium oxalate** and **calcium phosphate stones**. - These are typically unrelated to bacterial infections, unlike struvite stones. *Sodium* - **Sodium** is not a primary component of any common type of kidney stone. - While high sodium intake can increase the risk of stone formation, it does not directly form the stone matrix. *Potassium* - **Potassium** is not a characteristic component of kidney stones. - It plays a role in urinary pH regulation but is not directly incorporated into stone formation.
Question 9: All of the following are true about xanthogranulomatous pyelonephritis except which of the following?
- A. It is a form of chronic pyelonephritis
- B. Focal form is common in children
- C. Seen only in infancy (Correct Answer)
- D. Proteus mirabilis is the most common organism
Explanation: ***Seen only in infancy*** - Xanthogranulomatous pyelonephritis can occur in **adults** as well, not just in infancy, making this statement false [1]. - It is often associated with obstructive uropathy and chronic infection across various age groups. *Proteus is most common organism* - While **Proteus** species are commonly associated [1], the most frequent organism in xanthogranulomatous pyelonephritis can also include **E. coli**. - It reflects a polymicrobial infection rather than being limited to a single organism. *It is a form of chronic pyelonephritis* - Xanthogranulomatous pyelonephritis is indeed a variant of **chronic pyelonephritis**, characterized by extensive **granulomatous inflammation** [1]. - This chronic condition arises typically due to obstructive pathology leading to chronic infection. *Focal form is common in children* - The **focal form** is less common in children and is more frequently observed in **adults** with underlying conditions. - Children tend to present with a more diffuse form of **xanthogranulomatous pyelonephritis** when it occurs. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 939-940.
Question 10: Ectopic ureter may be frequently associated with which of the following conditions?
- A. Dysuria
- B. Paradoxical incontinence (Correct Answer)
- C. Bilateral hydroureter
- D. Oliguria
Explanation: ***Paradoxical incontinence*** - Ectopic ureters in females often insert distal to the external sphincter (e.g., vagina, vestibule), leading to **continuous leakage of urine** despite periods of normal voiding. This is known as paradoxical incontinence, where the bladder fills and empties normally, but urine also constantly dribbles from the ectopic opening. - In males, ectopic ureters usually insert proximal to the external sphincter (e.g., prostatic urethra, seminal vesicle) and therefore rarely cause incontinence but rather present with **ureteral obstruction** or **epididymitis**. *Oliguria* - **Oliguria** refers to a decreased urine output and is typically associated with **renal failure**, dehydration, or severe obstruction, not directly or frequently with an ectopic ureter itself. - An ectopic ureter may cause obstruction leading to **hydronephrosis** or renal damage, which could eventually lead to oliguria, but it is not the immediate or frequent direct association. *Dysuria* - **Dysuria** means painful urination, most commonly associated with **urinary tract infections (UTIs)**, urethritis, or bladder inflammation. - While an ectopic ureter can predispose to UTIs, dysuria is a symptom of infection rather than a direct, frequent consequence of the anatomical anomaly itself. *Bilateral hydroureter* - **Bilateral hydroureter** suggests obstruction of both ureters, often at the level of the bladder or urethra, or a systemic condition affecting both kidneys. - An ectopic ureter is usually a unilateral anomaly, causing **unilateral hydroureter** if it is obstructed, not typically bilateral.
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