Which hormone causes water retention by increasing sodium reabsorption?

A. Scattered areas of hypopigmentation of the skin is incorrect because hypopigmentation refers to lightened areas of skin, which are more typical of conditions like vitiligo. Psoriasis lesions are not defined by loss of pigment but by inflammation and thickened plaques.

B. Ruptured vesicles with yellowish-brown crusts is incorrect because this describes impetigo, a bacterial skin infection caused by Staphylococcus aureus or Streptococcus pyogenes. Impetigo presents with vesicles that rupture easily and form characteristic honey-colored crusts. Psoriasis does not involve vesicles or crusting.

C. Silvery scales covering red patches of skin is correct because this is the classic presentation of plaque psoriasis, the most common form of psoriasis. The lesions consist of well-demarcated, raised, erythematous plaques with silvery-white scales resulting from excessive keratinocyte proliferation and rapid epidermal turnover. Common sites include the elbows, knees, scalp, and lower back. The scales can flake off and may be itchy or painful.

D. Round papules with clear centers scattered over the body is incorrect because this description fits chickenpox (varicella), which presents with vesicular lesions with a clear center. Psoriasis lesions are plaques with scales, not small vesicular papules.

A. Decreased kidney production of erythropoietin is correct because in end-stage renal failure, the kidneys lose their ability to produce adequate amounts of erythropoietin, a hormone that stimulates the bone marrow to produce red blood cells. Without sufficient erythropoietin, red blood cell production decreases, leading to anemia. This is one of the most common causes of anemia in chronic kidney disease.

B. Increased hemoglobin levels in the blood is incorrect because anemia is characterized by decreased hemoglobin levels, not increased. End-stage renal disease leads to reduced red blood cell production, which lowers hemoglobin levels.

C. Decreased red blood cell destruction is incorrect because decreased destruction would actually increase red blood cell count, not cause anemia. In renal failure, anemia is mainly due to decreased production, not reduced destruction.

D. Increased glomerular filtration in the kidneys is incorrect because end-stage renal failure is associated with a decreased glomerular filtration rate (GFR), not increased. Reduced filtration contributes to the accumulation of waste products but does not directly cause anemia in the way decreased erythropoietin does.