A client with a sudden onset of big toe joint pain and swelling is diagnosed with gout. Which pathophysiologic process is producing the symptoms of gout?

Acne vulgaris is a common skin condition characterized by various types of lesions, including comedones, papules, and pustules, primarily affecting areas with a high density of sebaceous glands, such as the face, neck, chest, and upper back. Here's why option C is the correct choice:

A) Small, skin-colored, pedunculated papules in areas of skin folds and on other areas as skin tags:

This description is more characteristic of acrochordons or skin tags, which are benign skin growths commonly found in areas of friction or skin folds. Skin tags are not typically associated with acne vulgaris.

B) Hyperpigmented areas that vary in form and color and are slightly elevated from the skin:

This description suggests post-inflammatory hyperpigmentation, which can occur after resolution of inflammatory lesions in acne vulgaris. However, it does not capture the primary pathological findings observed in active acne lesions.

C) Hyperactive sebaceous areas forming comedones, papules, pustules on the face, neck, and upper back:

Correct. Acne vulgaris is characterized by the formation of various lesions, including comedones (open and closed), papules, and pustules, resulting from the obstruction of hair follicles and overactivity of sebaceous glands. These lesions typically appear on areas with a high density of sebaceous glands, such as the face, neck, chest, and upper back.

D) Sharply demarcated silvery scaling plaques with underlying redness on the elbows and knees:

This description is more indicative of psoriasis, a chronic autoimmune skin condition characterized by sharply demarcated, raised, silvery scaling plaques commonly affecting extensor surfaces such as the elbows and knees. Psoriasis lesions are distinct from those seen in acne vulgaris.

The loop of Henle, a critical structure within the nephron of the kidney, plays a key role in the concentration of urine through the process of countercurrent multiplication. Here's why option D is the correct choice:

A) Calyx:

The calyx is a structure in the kidney that collects urine from the renal papillae and channels it into the renal pelvis. It does not directly participate in the concentration of urine.

B) Proximal convoluted tubule:

The proximal convoluted tubule primarily reabsorbs water, electrolytes, and nutrients from the glomerular filtrate, but it does not contribute significantly to the concentration of urine.

C) Renal pelvis:

The renal pelvis is a funnel-shaped structure that collects urine from the calyces and funnels it into the ureter. It is not directly involved in the concentration of urine.

D) The loop of Henle:

Correct. The loop of Henle is the nephron segment responsible for generating a hypertonic medullary interstitium, which creates the osmotic gradient necessary for urine concentration. The loop of Henle achieves this through countercurrent multiplication, where the descending limb allows passive reabsorption of water, while the ascending limb actively pumps out sodium and chloride ions. This creates an osmotic gradient that allows for further water reabsorption in the collecting ducts, leading to concentrated urine.