A patient with psychologic disorder is being treated with a drug. Few months * he is worried that he is constantly thirsty and urinates copiously frequently throughout the day and night. Which of the following drugs most likely cause inappropriate secretion of ADH?

Correct Answer: B

Rationale: The correct answer is B: Lithium. Lithium is known to cause nephrogenic diabetes insipidus, a condition where the kidneys are unable to respond to antidiuretic hormone (ADH), leading to excessive urination and thirst. This is due to lithium disrupting the normal function of the kidneys in retaining water. Diazepam (A) is a benzodiazepine used for anxiety and does not affect ADH secretion. Haloperidol (C) is an antipsychotic that can cause hyperprolactinemia but not inappropriate ADH secretion. Phenytoin (D) is an anticonvulsant and does not impact ADH secretion.

Correct Answer: B

Rationale: The correct answer is B: 1-5 litres. This is the average volume of glomerular filtrate that adults produce daily. The kidneys filter around 180 liters of blood plasma daily, but only 1-5 liters of urine is excreted. The gall bladder (A) stores bile, not involved in urine production. The ureter (C) is a tube that carries urine from the kidney to the bladder, doesn't relate to the volume of filtrate. 80 liters (D) is too high for daily urine production and would lead to severe dehydration.

Correct Answer: B

Rationale: The correct answer is B. Without ADH, the proximal parts of the nephron are permeable to water, not impermeable. ADH acts on the distal tubules and collecting ducts to increase water reabsorption. This allows the body to retain water and concentrate urine. Choice A (ureter) is not related to ADH and Choice C and D are incomplete options.

Correct Answer: C

Rationale: The correct answer is C because vancomycin as a one-off 2 grams to CAPD bags is not sufficient for proven gram-positive infection. For CAPD peritonitis, continuous intraperitoneal antibiotics are required, not just a single dose. This is because peritoneal dialysis fluid is continuously present in the peritoneal cavity, necessitating ongoing antibiotic therapy. Choice A is incorrect because a positive Gram stain in only 10-40% of culture-positive bags does not rule out peritonitis. Choice B is incorrect as coagulase-negative staphylococci are the most common organisms isolated in CAPD peritonitis, not Staph aureus. Choice D is incorrect as antibiotics are usually needed parenterally in addition to intraperitoneal administration for severe cases or systemic infections.

Correct Answer: D

Rationale: The correct answer is D because the corpus spongiosum is a column of erectile tissue in the penis that surrounds the urethra and expands into the glans. This expansion forms the glans, which is the rounded tip of the penis. This is anatomically accurate as the glans is indeed an expanded cone-shaped structure at the distal end of the penis. A: The urethral meatus is actually located at the tip of the glans, which is at the distal end of the penis, not the ventral side. B: The prepuce is the foreskin that covers the glans, not the shaft of the penis. C: The penis is actually made up of three cylindrical columns of erectile tissue - two corpora cavernosa and one corpus spongiosum.