Stones Flashcards
Vignette: A 45-year-old man presents with recurrent kidney stones. On further evaluation, you suspect primary hyperparathyroidism as the underlying cause.
Options:
A) 2–5%
B) 3–5%
C) 10–40%
D) 20–40%
Correct Answer: B) 3–5%
Explanation:
A) 2–5%: Incorrect, the prevalence of Resorptive hypercalciuria due to primary hyperparathyroidism is 3–5%.
B) 3–5%: Correct, Resorptive hypercalciuria, often linked to primary hyperparathyroidism, has a prevalence of 3–5%.
C) 10–40%: Incorrect, this prevalence rate is for Hyperuricosuric calcium nephrolithiasis and Hypocitraturic calcium nephrolithiasis.
D) 20–40%: Incorrect, this prevalence rate corresponds to Absorptive hypercalciuria.
Memory Tool: Think “Resorp-three-five” to remember the prevalence of Resorptive hypercalciuria.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Knowing the prevalence of different types can help guide diagnostic evaluations.
Topic: Metabolic/Environmental defect causing Renal Hypercalciuria
Vignette: A 37-year-old woman experiences her third episode of renal stones within a year. A metabolic evaluation indicates impaired renal calcium reabsorption.
Options:
A) Absorptive hypercalciuria
B) Renal hypercalciuria
C) Renal phosphate leak
D) Hyperuricosuric calcium nephrolithiasis
Correct Answer: B) Renal hypercalciuria
Explanation:
A) Absorptive hypercalciuria: Incorrect, this condition is due to increased gastrointestinal calcium absorption.
B) Renal hypercalciuria: Correct, impaired renal calcium reabsorption leads to Renal hypercalciuria.
C) Renal phosphate leak: Incorrect, this is characterized by impaired renal phosphorus absorption.
D) Hyperuricosuric calcium nephrolithiasis: Incorrect, this is due to dietary purine excess or uric acid overproduction.
Memory Tool: “Hyper-calciu-‘Renal’-ya” to remember that renal calcium problems relate to Renal hypercalciuria.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Understanding the metabolic cause can inform targeted treatment.
Topic: Prevalence of Cystinuria in Nephrolithiasis
Vignette: A 24-year-old man presents with painful renal colic. You diagnose him with Cystinuria.
Options:
A) <1%
B) 5–10%
C) 15–30%
D) 20–40%
Correct Answer: A) <1%
Explanation:
A) <1%: Correct, Cystinuria is a rare cause of nephrolithiasis, with a prevalence of less than 1%.
B) 5–10%: Incorrect, this prevalence range is for Hypomagnesiuric calcium nephrolithiasis.
C) 15–30%: Incorrect, this corresponds to Idiopathic low urine pH.
D) 20–40%: Incorrect, this is the prevalence of Absorptive hypercalciuria.
Memory Tool: Think “Cysti-nu-ria, <1 rare-ia” to remember its rarity.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Recognizing rare causes is crucial for an accurate diagnosis.
opic: Prevalence of Hypomagnesiuric Calcium Nephrolithiasis
Vignette: A 52-year-old woman is experiencing repeated bouts of kidney stones. Her lab results show decreased intestinal magnesium absorption.
Options:
A) 2–15%
B) 3–5%
C) 5–10%
D) 10–50%
Correct Answer: C) 5–10%
Explanation:
A) 2–15%: Incorrect, this is the prevalence range for Hyperoxaluric calcium nephrolithiasis.
B) 3–5%: Incorrect, this corresponds to Resorptive hypercalciuria.
C) 5–10%: Correct, the prevalence of Hypomagnesiuric calcium nephrolithiasis is 5–10%.
D) 10–50%: Incorrect, this prevalence range is for Hypocitraturic calcium nephrolithiasis and Low urine volume.
Memory Tool: Think of “Hypo-magnesiuric, mag-5-10” for easy recall.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Knowing the prevalence of a condition aids in diagnosis and management.
Topic: Metabolic/Environmental defect causing Hyperuricosuric Calcium Nephrolithiasis
Vignette: A 60-year-old male has been diagnosed with Hyperuricosuric calcium nephrolithiasis. He is a known meat lover.
Options:
A) Oxalate overproduction
B) Dietary purine excess
C) Impaired renal phosphorus absorption
D) Gastrointestinal alkali loss
Correct Answer: B) Dietary purine excess
Explanation:
A) Oxalate overproduction: Incorrect, this corresponds to Primary hyperoxaluria.
B) Dietary purine excess: Correct, Hyperuricosuric calcium nephrolithiasis often occurs due to dietary purine excess or uric acid overproduction.
C) Impaired renal phosphorus absorption: Incorrect, this leads to Renal phosphate leak.
D) Gastrointestinal alkali loss: Incorrect, this is related to Chronic diarrheal syndrome in Hypocitraturic calcium nephrolithiasis.
Memory Tool: Remember “Hyper-‘uric’-osuric = excess purine” to keep the link in mind.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Dietary modification may be key in treating this form of nephrolithiasis.
opic: Prevalence of Low Urine Volume as a Cause of Nephrolithiasis
Vignette: A 38-year-old woman presents with kidney stones. She confesses to consuming very little water daily.
Options:
A) <1%
B) 5–10%
C) 10–50%
D) 15–30%
orrect Answer: C) 10–50%
Explanation:
A) <1%: Incorrect, this is the prevalence of Cystinuria.
B) 5–10%: Incorrect, this corresponds to Hypomagnesiuric calcium nephrolithiasis.
C) 10–50%: Correct, low urine volume due to inadequate fluid intake can cause nephrolithiasis in 10–50% of cases.
D) 15–30%: Incorrect, this is the prevalence for Idiopathic low urine pH.
Memory Tool: “Low urine? High chance! 10–50%” to remember the prevalence range.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Emphasizing hydration may prevent future episodes.
Question 1: A patient is found to have struvite stones and you suspect the presence of a urease-producing bacteria. Which of the following gram-negative bacteria is most likely (>90% of isolates) to produce urease?
Options:
A. Haemophilus influenzae
B. Proteus mirabilis
C. Pseudomonas aeruginosa
D. Klebsiella pneumoniae
Correct Answer:
B. Proteus mirabilis
Explanation:
A. Haemophilus influenzae: Occasional urease-producer (5%-30% of isolates).
B. Proteus mirabilis: Usually produces urease (>90% of isolates).
C. Pseudomonas aeruginosa: Occasional urease-producer (5%-30% of isolates).
D. Klebsiella pneumoniae: Occasional urease-producer (5%-30% of isolates).
Memory Tool:
Remember the phrase “Proteus Mira-Bliss” to recall that Proteus mirabilis is blissfully (>90%) urease-positive.
Reference Citation:
Gleeson MJ, Griffith DP: Infection stones. In Resnick MI, Pak CYC, editors: Urolithiasis: a medical and surgical reference, Philadelphia, 1990, Saunders, p 115. (Table 91.3)
Rationale:
Knowing the urease-producing capacity of bacteria is essential for accurate diagnosis and treatment of struvite stones.
Question 2: Which gram-positive organism is LEAST likely to produce urease based on the given table?
Options:
A. Corynebacterium ulcerans
B. Bacillus species
C. Peptococcus asaccharolyticus
D. Staphylococcus aureus
Correct Answer:
D. Staphylococcus aureus
Explanation:
A. Corynebacterium ulcerans: Listed as a urease-producer.
B. Bacillus species: Listed as a urease-producer.
C. Peptococcus asaccharolyticus: Listed as a urease-producer.
D. Staphylococcus aureus: Listed as a urease-producer, but unlike the others, it is well-known to produce urease occasionally rather than usually.
Memory Tool:
Remember “Staph Aure-LEAST” to remember that Staphylococcus aureus is least likely among the options to produce urease.
Reference Citation:
Gleeson MJ, Griffith DP: Infection stones. In Resnick MI, Pak CYC, editors: Urolithiasis: a medical and surgical reference, Philadelphia, 1990, Saunders, p 115. (Table 91.3)
Rationale:
Identifying organisms least likely to produce urease can help in differential diagnosis and in directing antibiotic therapy.
Question 3: A patient presents with suspected infection stones, and Mycoplasma is being considered as a causative agent. Which Mycoplasma species should be suspected as a urease-producer?
Options:
A. T-strain Mycoplasma
B. Mycoplasma genitalium
C. Ureaplasma urealyticum
D. Mycoplasma pneumoniae
Correct Answer:
C. Ureaplasma urealyticum
Explanation:
A. T-strain Mycoplasma: Listed as a urease-producer, but it’s not typically associated with urological issues.
B. Mycoplasma genitalium: Not listed in the table.
C. Ureaplasma urealyticum: Specifically listed as a Mycoplasma species that usually produces urease.
D. Mycoplasma pneumoniae: Not listed in the table.
Memory Tool:
“Urea-plasma, Urea-lytic!”—Ureaplasma urealyticum is the Mycoplasma species concerned with urea breakdown.
Reference Citation:
Gleeson MJ, Griffith DP: Infection stones. In Resnick MI, Pak CYC, editors: Urolithiasis: a medical and surgical reference, Philadelphia, 1990, Saunders, p 115. (Table 91.3)
Rationale:
Differentiating between Mycoplasma species is vital for accurate diagnosis and treatment of infection stones.
uestion 4: You suspect an infection stone caused by yeast in a patient. Which of the following yeasts is NOT listed as a urease-producer?
Options:
A. Cryptococcus
B. Candida albicans
C. Rhodotorula
D. Sporobolomyces
orrect Answer:
B. Candida albicans
Explanation:
A. Cryptococcus: Listed as a urease-producing yeast.
B. Candida albicans: Not listed as a urease-producer in the table; Candida humicola is listed instead.
C. Rhodotorula: Listed as a urease-producing yeast.
D. Sporobolomyces: Listed as a urease-producing yeast.
Memory Tool:
Remember “Candida Albi-GONE” to help remember that Candida albicans is gone from the list of urease-producers.
Reference Citation:
Gleeson MJ, Griffith DP: Infection stones. In Resnick MI, Pak CYC, editors: Urolithiasis: a medical and surgical reference, Philadelphia, 1990, Saunders, p 115. (Table 91.3)
Rationale:
Knowing which yeasts don’t produce urease could guide treatment choices and further diagnostics.
Clinical Vignette:
You are consulting for a patient who reports having sharp, intermittent pain in the lower abdomen. Upon microscopic examination of a collected urinary calculus, you observe an “envelope, tetrahedral” appearance.
Multiple-Choice Options:
A) Calcium oxalate monohydrate
B) Calcium oxalate dihydrate
C) Calcium phosphate-apatite
D) Uric acid
Correct Answer:
B) Calcium oxalate dihydrate
In-Depth Explanation:
A) Calcium oxalate monohydrate: Incorrect. This type of urinary calculus usually has an “hourglass” appearance under the microscope.
B) Calcium oxalate dihydrate: Correct. The “envelope, tetrahedral” microscopic appearance is characteristic of calcium oxalate dihydrate crystals.
C) Calcium phosphate-apatite: Incorrect. This typically appears “amorphous” under microscopic examination.
D) Uric acid: Incorrect. These crystals usually appear as “amorphous shards, plates” microscopically.
Clinical Vignette:
A patient has chronic kidney issues and upon examination, you observe urinary calculi with a needle-shaped appearance.
Multiple-Choice Options:
A) Brushite
B) Cystine
C) Magnesium ammonium phosphate (struvite)
D) Uric acid
Correct Answer:
A) Brushite
In-Depth Explanation:
A) Brushite: Correct. The “needle-shaped” appearance is characteristic of Brushite calculi.
B) Cystine: Incorrect. Cystine calculi would have a “hexagonal” appearance.
C) Magnesium ammonium phosphate (struvite): Incorrect. These typically appear as “rectangular, coffin-lid” shapes.
D) Uric acid: Incorrect. Uric acid crystals appear as “amorphous shards, plates.”
Memory Tool:
“Brushite is like a needle in a haystack” can help you remember the needle-shaped appearance of Brushite.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Recognizing the microscopic appearance of various calculi allows for better treatment planning, especially for patients with chronic kidney issues.
Clinical Vignette:
A young patient presents with a history of recurrent urinary tract stones. A microscopic evaluation reveals a hexagonal-shaped urinary calculus.
Multiple-Choice Options:
A) Magnesium ammonium phosphate (struvite)
B) Brushite
C) Cystine
D) Uric acid
Correct Answer:
C) Cystine
In-Depth Explanation:
A) Magnesium ammonium phosphate (struvite): Incorrect. Struvite usually appears as “rectangular, coffin-lid” shapes.
B) Brushite: Incorrect. Brushite calculi are “needle-shaped.”
C) Cystine: Correct. A “hexagonal” shape is characteristic of Cystine calculi.
D) Uric acid: Incorrect. These crystals usually appear as “amorphous shards, plates.”
Memory Tool:
Remember, “Cystine is Six-sided” to associate the hexagonal shape with Cystine.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Identifying Cystine calculi is especially important in younger patients with recurrent urinary tract stones, as it may indicate a genetic predisposition requiring specialized treatment.
Clinical Vignette:
A 40-year-old woman presents with fever and chills in addition to urinary symptoms. Microscopic examination of her urinary calculus shows a “rectangular, coffin-lid” shape.
Multiple-Choice Options:
A) Calcium phosphate-apatite
B) Magnesium ammonium phosphate (struvite)
C) Calcium oxalate monohydrate
D) Uric acid
Correct Answer:
B) Magnesium ammonium phosphate (struvite)
In-Depth Explanation:
A) Calcium phosphate-apatite: Incorrect. Typically appears as “amorphous.”
B) Magnesium ammonium phosphate (struvite): Correct. Struvite calculi are usually “rectangular, coffin-lid” in shape.
C) Calcium oxalate monohydrate: Incorrect. This type generally has an “hourglass” appearance.
D) Uric acid: Incorrect. These usually appear as “amorphous shards, plates.”
Memory Tool:
Think “Struvite is your coffin-lid ticket to UTIs” to remember its rectangular, coffin-lid shape and its association with urinary tract infections.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Struvite stones are often associated with infections, and identifying them can guide the choice of antibiotics alongside stone management.
Clinical Vignette:
You are treating an elderly male patient who has been experiencing flank pain. Microscopic evaluation of his urinary calculus shows “amorphous shards, plates.”
Multiple-Choice Options:
A) Brushite
B) Cystine
C) Calcium phosphate-apatite
D) Uric acid
Correct Answer:
D) Uric acid
In-Depth Explanation:
A) Brushite: Incorrect. Brushite calculi would show a “needle-shaped” appearance.
B) Cystine: Incorrect. These are usually “hexagonal” in shape.
C) Calcium phosphate-apatite: Incorrect. This type appears “amorphous,” but not as shards or plates.
D) Uric acid: Correct. Uric acid calculi present as “amorphous shards, plates.”
Memory Tool:
“Uric Acid is Unpredictable Shards” can help you remember the unique appearance of uric acid calculi.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Knowing the characteristic appearance of uric acid stones may point to specific dietary factors or metabolic issues, aiding in targeted treatment.
Clinical Vignette:
A 30-year-old male is experiencing recurring urinary tract infections. Upon microscopic evaluation, you notice the urinary calculus appears “amorphous.”
Multiple-Choice Options:
A) Calcium phosphate-apatite
B) Magnesium ammonium phosphate (struvite)
C) Calcium oxalate monohydrate
D) Uric acid
Correct Answer:
A) Calcium phosphate-apatite
In-Depth Explanation:
A) Calcium phosphate-apatite: Correct. The “amorphous” appearance is characteristic of Calcium phosphate-apatite calculi.
B) Magnesium ammonium phosphate (struvite): Incorrect. These usually have a “rectangular, coffin-lid” appearance.
C) Calcium oxalate monohydrate: Incorrect. These appear as “hourglass.”
D) Uric acid: Incorrect. These appear as “amorphous shards, plates.”
Memory Tool:
“Phosphate is Formless” can help you remember the amorphous nature of Calcium phosphate-apatite stones.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Understanding the amorphous nature of Calcium phosphate-apatite stones may prompt further evaluation for underlying causes, especially in younger patients with recurrent infections.
Question 1:
A 45-year-old male presents with recurrent calcium oxalate stones. After a thorough evaluation, you decide to start him on a thiazide diuretic. Which of the following doses is correct for Hydrochlorothiazide for this indication?
A. 50 mg PO daily
B. 25 mg PO bid
C. 10 mg PO daily
D. 100 mg PO daily
Correct Answer: B
Explanation:
A: 50 mg daily is not the recommended dosage for Hydrochlorothiazide for urinary calculi. It’s an incorrect dosage.
B: 25 mg PO bid is the correct dosage as per the guidelines provided in Table 92.4.
C: 10 mg daily is lower than the recommended dosage.
D: 100 mg PO daily is excessive and not recommended.
Memory Tool: “25 Twice” helps you remember the dose and frequency.
Reference Citation: Table 92.4
Rationale: Knowing the correct dosage is crucial for effective treatment and minimizing side effects.
What is the appropriate dosage of Allopurinol to prevent urinary calculi?
A. 100 mg PO daily
B. 250 mg PO daily
C. 300 mg PO daily
D. 400 mg PO daily
Correct Answer: C
Explanation:
A: 100 mg PO daily is below the recommended dosage.
B: 250 mg daily is close but not the recommended dose.
C: 300 mg PO daily is the correct dose according to Table 92.4.
D: 400 mg PO daily is above the recommended dose.
Memory Tool: “Alo-300” to remember the dosage.
Reference Citation: Table 92.4
Rationale: Prescribing the correct dose of Allopurinol can prevent complications related to urinary calculi.
For a patient who has frequent uric acid stones, which medication can be given, and at what dosage according to Table 92.4?
A. Potassium citrate at 10 mEq PO daily
B. Potassium citrate at 20 mEq PO bid-tid
C. Sodium cellulose phosphate at 5 g/day
D. Magnesium gluconate at 0.5–1 g tid
Correct Answer: B
Explanation:
A: The dosage for Potassium citrate is not correct. It is lower than the recommended dosage.
B: Potassium citrate at 20 mEq PO bid-tid is the correct choice for uric acid stones as per the table.
C: Sodium cellulose phosphate’s recommended dosage is 10–15 g/day, not 5 g/day.
D: Magnesium gluconate could be an option but is not specified for uric acid stones in the table.
Memory Tool: “Citrate Twenty Twice-Three”
Reference Citation: Table 92.4
Rationale: Correct medication and dosage are crucial for targeted treatment of different types of urinary calculi.
Question 4:
You’re managing a patient with cystine stones. Which medication, according to Table 92.4, would be appropriate for management, and what is its recommended dosage?
A. α-Mercaptopropionyl glycine 200 mg PO daily
B. α-Mercaptopropionyl glycine 100 mg PO bid
C. d-Penicillamine 500 mg PO daily
D. Acetohydroxamic acid 500 mg PO bid
Correct Answer: B
Explanation:
A: The dosage is not accurate. It should be 100 mg PO bid.
B: α-Mercaptopropionyl glycine 100 mg PO bid is the correct dosage according to Table 92.4 and is suitable for cystine stones.
C: d-Penicillamine is a choice, but 500 mg is not the recommended dosage according to the table.
D: Acetohydroxamic acid is not recommended for cystine stones according to Table 92.4.
Memory Tool: “Alpha 100 Twice” for α-Mercaptopropionyl glycine.
Reference Citation: Table 92.4
Rationale: Understanding medication and dosages for specific stone types is vital for effective treatment.
Which medication can be prescribed at a dosage of 25–50 mg PO daily for preventing urinary calculi, according to Table 92.4?
A. Hydrochlorothiazide
B. Chlorthalidone
C. Indapamide
D. Captopril
Correct Answer: B
Explanation:
A: Hydrochlorothiazide is given at 25 mg PO bid, not 25–50 mg PO daily.
B: Chlorthalidone is correctly prescribed at 25–50 mg PO daily.
C: Indapamide’s dosage is 2.5 mg PO daily.
D: Captopril has a different dosing schedule altogether.
Memory Tool: “Chlor 25 to 50” to remember Chlorthalidone dosage.
Reference Citation: Table 92.4
Rationale: Being aware of the appropriate dosages for each medication is crucial for effective stone management.
What is the advised dosage of Magnesium gluconate to prevent urinary calculi?
A. 0.5–1 g bid
B. 0.5–1 g qid
C. 0.5–1 g tid
D. 0.5–1 g daily
Correct Answer: C
Explanation:
A: Bid is incorrect, the advised frequency is tid.
B: Qid is more frequent than the recommended tid.
C: 0.5–1 g tid is the correct dosage.
D: Daily is less frequent than the recommended tid.
Memory Tool: “Magne-Three” to remember tid dosing for Magnesium gluconate.
Reference Citation: Table 92.4
Rationale: Correct dosing is crucial for effective prophylaxis against urinary calculi.
Question 7:
According to Table 92.4, what is the correct dosage of Sodium cellulose phosphate for preventing urinary calculi?
A. 5–10 g/day divided with meals
B. 10–15 g/day divided with meals
C. 20 g/day divided with meals
D. 10 g/day divided with meals
Correct Answer: B
Explanation:
A: This dosage is lower than the recommended 10–15 g/day.
B: 10–15 g/day divided with meals is the correct dosage according to Table 92.4.
C: 20 g/day exceeds the recommended dosage.
D: This dosage is within the range but doesn’t capture the full recommended range of 10–15 g/day.
Memory Tool: “Cellu-10 to 15” to remember Sodium cellulose phosphate dosage.
Reference Citation: Table 92.4
Rationale: Accurate dosing ensures effectiveness while minimizing potential side effects.
A 55-year-old woman has been diagnosed with calcium phosphate stones. What is the appropriate dose of Orthophosphate for preventing future episodes, according to Table 92.4?
A. 0.5 g PO bid
B. 1 g PO tid
C. 0.5 g PO tid
D. 2 g PO daily
Correct Answer: C
Explanation:
A: Bid is not the recommended frequency; it should be tid.
B: The dose is too high; it should be 0.5 g.
C: 0.5 g PO tid is the correct dosage.
D: This dosage is not advised as per the table.
Memory Tool: “Ortho-0.5-Three” for remembering the dose and frequency.
Reference Citation: Table 92.4
Rationale: Specific knowledge of dosages for certain stone types aids in providing the best patient care.