A-50-year-old man has a history of frequent episodes of renal colic with high calcium renal stones. The most useful agent in the treatment of recurrent calcium stones is:

Correct Answer: C

Rationale: Rationale: The correct answer is C: Hydrochlorothiazide. It is a thiazide diuretic that reduces calcium excretion, preventing stone formation. Furosemide (A) and spironolactone (B) do not target calcium excretion specifically. Acetazolamide (D) is a carbonic anhydrase inhibitor and not commonly used for calcium stones.

Correct Answer: D

Rationale: The correct answer is D: Conivaptan. Conivaptan is a non-peptide competitive antagonist of ADH, indicated for managing SIADH by blocking ADH's water-sparing effects in the collecting ducts. Mannitol (A) is an osmotic diuretic used for reducing intracranial pressure, not specifically for SIADH. Bumetanide (B) is a loop diuretic used for conditions like heart failure and edema. Spironolactone (C) is a potassium-sparing diuretic used for conditions like hypertension and heart failure, not specifically for SIADH.

Correct Answer: C

Rationale: Acetazolamide is a carbonic anhydrase inhibitor that reduces intraocular pressure by decreasing aqueous humor production, making it effective in treating glaucoma. It is not commonly used as a diuretic due to its short duration of action and side effects. Therefore, choice C is correct. Choices A, B, and D are incorrect as acetazolamide is not indicated for liver cirrhosis, CHF, or kidney failure. Liver cirrhosis typically requires diuretics to manage ascites, CHF is managed with loop diuretics, and kidney failure may require different types of diuretics based on the underlying cause.

Correct Answer: C

Rationale: The correct answer is C: Encourage fluid intake of 3000 mL/day. This is important post-nephrolithotomy to prevent urinary stasis and aid in flushing out potential stone fragments. Adequate hydration also helps in preventing urinary tract infections. Administering IV fluids and blood transfusions (A) may be necessary in certain cases, but not specifically indicated for this scenario. Administering narcotic analgesics (B) may be required for pain management, but it does not address the underlying issue of preventing complications. Suggesting herbs or spices (D) is unrelated and may not be recommended due to potential interactions with medications.

Correct Answer: C

Rationale: The correct answer is C because hematuria (blood in urine) and change in urinary pattern are classic symptoms of bladder cancer. Hematuria is the most common presenting symptom. Weight loss and low back pain (choice A) are more indicative of advanced stages of cancer. Fatigue and anemia (choice B) are nonspecific symptoms. Difficulty initiating urinary stream and nocturia (choice D) may be seen in other conditions but are not specific to bladder cancer.