Which pieces of information link up correctly?

Choice A rationale
Hypercalcemia is characterized by increased calcium levels in the blood, often due to increased absorption of calcium from the gut. However, in chronic kidney disease (CKD), the kidneys’ ability to activate vitamin D is impaired, leading to decreased calcium absorption from the gut, not increased. Therefore, hypercalcemia is not a typical sign of CKD1.
Choice B rationale
A positive Chvostek’s sign is indicative of hypocalcemia, which is a common symptom in CKD. The kidneys’ reduced ability to activate vitamin D leads to decreased calcium absorption from the gut, resulting in low calcium levels in the blood. This hypocalcemia can cause neuromuscular irritability, leading to a positive Chvostek’s sign.
Choice C rationale
Tetany is a condition characterized by muscle cramps and spasms, often due to hypocalcemia. In CKD, hypocalcemia occurs due to the kidneys’ inability to activate vitamin D, leading to decreased calcium absorption from the gut. This hypocalcemia can cause hyperexcitability of nerves and muscles, resulting in tetany.
Choice D rationale
Hyperphosphatemia is characterized by high phosphate levels in the blood. In CKD, the kidneys’ ability to excrete phosphate is impaired, leading to its accumulation in the blood. However, this is not directly related to the inability to absorb phosphate from the gut but rather the kidneys’ reduced excretion capacity.

Choice A rationale
Urine specific gravity of 1.029 indicates concentrated urine, which is common in dehydration but not specific to prerenal AKI. It reflects the kidney’s ability to concentrate urine in response to fluid deficit.
Choice B rationale
BUN of 28 mg/dL can indicate dehydration or renal impairment. However, it is not as specific as creatinine in diagnosing prerenal AKI. BUN can be elevated due to other factors like high protein intake or gastrointestinal bleeding.
Choice C rationale
Creatinine of 2.4 mg/dL is a critical indicator of kidney function. Elevated creatinine levels are more specific to renal impairment, including prerenal AKI, as they reflect the kidney’s ability to filter waste products.
Choice D rationale
Dry mucous membranes are a sign of dehydration but are not specific to prerenal AKI. They indicate fluid volume deficit but do not directly reflect kidney function.