Question

A 38 year old woman has sudden onset of nausea and vomiting and severe, colicky flank pain that radiates to the perineum. On physical examination, the patient shifts position frequently and seems unable to sit still. Urinalysis shows trace protein, 3+ blood, pH = 7.2. Microscopic analysis shows many red cells and a few white cells, but no casts or bacteria. Laboratory analysis shows: Na⁺ 141 K⁺ 3.0, Cl⁻ 119, HCO³⁻12, BUN 17, Creatinine 1.0, glucose 111, calcium 9.8, magnesium 1.6, phosphate 3.0. Which of the following is the most likely etiology of this patient's electrolyte abnormalities?

A. Increased production of endogenous lactic acid
B. Decreased net secretion of H+ at the distal renal tubule
C. Deficiency of aldosterone
D. Excessive release of parathyroid hormone
E. Physiological stress response to pain

Answer 1

The most likely etiology of this woman's electrolyte abnormalities is chronic renal disease with acidosis due to poor tubular reabsorption of Na.

Step-by-step explanation:

The most likely etiology of this woman's electrolyte abnormalities is chronic renal disease with acidosis due to poor tubular reabsorption of Na. The presence of trace protein and 3+ blood in the urinalysis, along with the absence of casts or bacteria, suggests kidney dysfunction. The electrolyte abnormalities, such as low potassium (3.0 mmol/L) and low bicarbonate (12 mmol/L), are consistent with acidosis resulting from impaired tubular reabsorption of sodium in the kidney.