Laboratory abnormalities typical of renal hydrothorax include:

Laboratory abnormalities typical of renal hydrothorax include:

• A. Hypokalemia and hypercalcemia
• B. Hyperkalemia and elevated creatinine with decreased eGFR
• C. Hyperphosphatemia and hyponatremia only
• D. Normal kidney function with nonpitting edema

Answer: (B)

In renal hydrothorax, the labs reflect impaired kidney function. When the kidneys aren’t filtering well, potassium is not excreted effectively, leading to hyperkalemia, and waste products accumulate, shown as an elevated creatinine. The estimated glomerular filtration rate (eGFR) drops as nephron function declines. So the combination of hyperkalemia with elevated creatinine and a decreased eGFR is the classic lab pattern you’d expect in this setting. Other choices don’t fit because they imply electrolyte or kidney-function patterns that are not typical of renal failure. For example, renal failure-driven conditions usually present with high potassium and rising creatinine with reduced GFR, not low potassium or normal kidney function with edema.

In renal hydrothorax, the labs reflect impaired kidney function. When the kidneys aren’t filtering well, potassium is not excreted effectively, leading to hyperkalemia, and waste products accumulate, shown as an elevated creatinine. The estimated glomerular filtration rate (eGFR) drops as nephron function declines. So the combination of hyperkalemia with elevated creatinine and a decreased eGFR is the classic lab pattern you’d expect in this setting.

Other choices don’t fit because they imply electrolyte or kidney-function patterns that are not typical of renal failure. For example, renal failure-driven conditions usually present with high potassium and rising creatinine with reduced GFR, not low potassium or normal kidney function with edema.