SHM's Clinical Quick Talks-Metabolic Acidosis

Pdf Summary

The document is a comprehensive guide on diagnosing and managing metabolic acidosis, authored by Jennifer K. Readlynn, MD, FHM. It outlines a systematic approach for identifying metabolic acidosis and other potential acid-base disorders in patients, detailing the use of blood gas analyses to determine the primary cause—whether metabolic or respiratory—and applying Winter’s formula for evaluation. The text differentiates between anion gap metabolic acidosis (AGMA) and non-anion gap metabolic acidosis (NAGMA) and provides formulas and criteria for assessment, such as the anion and osmolar gaps.<br /><br />Metabolic acidosis can significantly impact patient health, increasing the risk of bone demineralization, muscle catabolism, chronic kidney disease (CKD) progression, and mortality. The treatment varies between chronic and acute cases, with sodium bicarbonate playing a crucial role. Chronic cases should maintain a serum bicarbonate level of 24 mmol/L. In acute scenarios, intravenous bicarbonate is recommended if the pH is below 7.1, adjusting the dosage based on the patient’s volume status and underlying cause.<br /><br />Specific types of renal tubular acidosis (RTA) are discussed: <br />- Type 1 involves distal tubule defects leading to stone formation,<br />- Type 2 impacts proximal tubules and is associated with Fanconi syndrome, and <br />- Type 4 is characterized by hypoaldosteronism and hyperkalemia.<br /><br />Non-RTA causes of NAGMA include excessive chloride administration, plasma exchanges, and bicarbonate losses from GI issues. For AGMA, common contributors include ethylene glycol, methanol, ketoacidosis, and salicylate intoxication. The document stresses not to mix sodium bicarbonate with normal saline, turning it hypertonic, and highlights resources and mnemonics useful for practitioners.

Asset Subtitle

Jennifer Readlynn

Keywords

metabolic acidosis

anion gap

blood gas analysis

Winter's formula

renal tubular acidosis

sodium bicarbonate

chronic kidney disease

hyperkalemia

ketoacidosis

ethylene glycol