Which disorder is best characterized by laboratory findings of increased serum inorganic phosphorus, magnesium, potassium, uric acid, urea, and creatinine, with decreased serum calcium and erythropoietin?

Which disorder is best characterized by laboratory findings of increased serum inorganic phosphorus, magnesium, potassium, uric acid, urea, and creatinine, with decreased serum calcium and erythropoietin?

• A. Chronic renal failure
• B. Renal tubular disease
• C. Nephrotic syndrome
• D. Acute glomerulonephritis

Answer: (A)

When kidney function declines, wastes and minerals start building up because the kidneys can’t filter them out effectively. In chronic renal failure, the reduced glomerular filtration rate leads to retention of nitrogenous wastes (urea and creatinine), uric acid, and electrolytes such as phosphate, potassium, and magnesium. Phosphate retention drives a drop in calcium levels, partly through binding and reduced activation of vitamin D, so serum calcium falls. The kidneys also lose their ability to produce erythropoietin, leading to lower erythropoietin levels and anemia. This combination—high phosphate, potassium, magnesium, uric acid, urea, and creatinine with low calcium and erythropoietin—mirrors the classic lab pattern seen in chronic renal failure. Renal tubular disease often involves phosphate wasting and different calcium handling, so the specific pattern is less characteristic. Nephrotic syndrome centers on protein loss and edema with its own electrolyte shifts, not this full retention profile. Acute glomerulonephritis presents more with abrupt nephritic features like hematuria and proteinuria and variable, less defining electrolyte changes.

When kidney function declines, wastes and minerals start building up because the kidneys can’t filter them out effectively. In chronic renal failure, the reduced glomerular filtration rate leads to retention of nitrogenous wastes (urea and creatinine), uric acid, and electrolytes such as phosphate, potassium, and magnesium. Phosphate retention drives a drop in calcium levels, partly through binding and reduced activation of vitamin D, so serum calcium falls. The kidneys also lose their ability to produce erythropoietin, leading to lower erythropoietin levels and anemia. This combination—high phosphate, potassium, magnesium, uric acid, urea, and creatinine with low calcium and erythropoietin—mirrors the classic lab pattern seen in chronic renal failure.

Renal tubular disease often involves phosphate wasting and different calcium handling, so the specific pattern is less characteristic. Nephrotic syndrome centers on protein loss and edema with its own electrolyte shifts, not this full retention profile. Acute glomerulonephritis presents more with abrupt nephritic features like hematuria and proteinuria and variable, less defining electrolyte changes.