L.S. is brought to the emergency department for management of acute mushroom poisoning. Her respirations are slow and shallow, and she is nonresponsive. She is admitted to the critical care unit to be closely monitored for the development of respiratory failure and renal failure, which often accompany mushroom poisoning. Her urine output is decreased to about 20 ml/hr. Her laboratory values are serum K+ = 5.7 mEq/L; arterial blood gases (ABGs): pH = 7.13, PaCO2 = 56 mm Hg, PaO2 = 89 mm Hg, HCO3- = 18 mEq/L.
1A. What is the most likely cause of L.S.’s potassium imbalance? Explain the role of the kidney in potassium excretion
Answer: L.S. is experiencing a intrarenal acute renal failure in the category of tubular necrosis (due to ingested mushroom toxins).
The kidneys helps to maintain the electrolyte concentrations by filtering electrolytes and water from blood, routing some to the blood, and excreting any excess into the urine.
Therefore, the kidneys help to maintain a balance between daily consumption and excretion of electrolytes and water.
Explanation:
Daily variations in potassium excretion are controlled mainly by changes in secretion in distal and collecting tubules.
• Maintaining potassium balance depends primarily on renal excretion which is determined by:
• the rate of potassium filtration
• the rate of potassium reabsorption by the tubules o the rate of potassium secretion by the tubules
i.e. About 65% the filtered potassium is reabsorbed the proximal tubule and another 25% to 30% in the ascending loop of Henle.
