The parents of a child newly diagnosed with cystic fibrosis (CF) are concerned about the secretions and respiratory issues their child is experiencing. Which pathophysiological process should the nurse use to respond to the parents?

Choice A reason: Insulin reduces serum glucose in diabetes mellitus, not water loss in diabetes insipidus (DI). DI results from vasopressin deficiency, causing excessive urination. Insulin is irrelevant, as DI is a fluid balance disorder, not a glucose metabolism issue, making this response incorrect and misleading for the client.

Choice B reason: Assessing dietary habits and glucose levels pertains to diabetes mellitus, not diabetes insipidus. DI involves water loss due to vasopressin deficiency, not glucose dysregulation. This response misaligns with DI’s pathophysiology, as insulin or glucose monitoring is unnecessary, and vasopressin therapy is the standard treatment.

Choice C reason: Maintaining normal serum glucose is a goal for diabetes mellitus, not diabetes insipidus, which involves water loss from vasopressin deficiency. DI treatment focuses on fluid balance via vasopressin, not glucose control. This response is incorrect, as it conflates DI with an unrelated metabolic condition.

Choice D reason: Diabetes insipidus is managed with vasopressin (ADH) therapy to reduce excessive urination and conserve water, addressing the underlying deficiency. This response accurately explains DI’s treatment, distinguishing it from diabetes mellitus and clarifying that insulin is not needed, aligning with evidence-based endocrinology practice for fluid balance.

Choice A reason: The loop of Henle regulates water and electrolyte reabsorption, not protein filtration. Proteinuria results from glomerular damage, allowing proteins to leak into urine. The loop’s role in concentration does not involve protein handling, making it incorrect for the structure impaired in CKD-related proteinuria.

Choice B reason: The glomerulus filters blood, normally preventing large proteins from entering urine. In CKD, glomerular damage (e.g., from hypertension or diabetes) increases permeability, causing proteinuria. This is a hallmark of glomerular injury, aligning with CKD’s pathophysiology, making the glomerulus the correct structure responsible for proteinuria.

Choice C reason: The distal convoluted tubule regulates electrolytes and acid-base balance, not protein filtration. Proteinuria stems from glomerular dysfunction, not tubular issues. The distal tubule’s role in reabsorption does not involve proteins, making it incorrect for the structure causing proteinuria in chronic kidney disease.

Choice D reason: Bowman’s capsule collects glomerular filtrate but does not filter proteins itself. Proteinuria occurs due to glomerular barrier damage, allowing proteins to pass into the capsule. While adjacent, the capsule is not the primary impaired structure, making the glomerulus the correct choice for CKD-related proteinuria.