A 2-year-old boy from urban Delhi presents with acute watery diarrhea and clinical signs of dehydration. His serum sodium is 128 mEq/L, potassium is 2.8 mEq/L, and chloride is 95 mEq/L. Regarding electrolyte abnormalities and their management in acute diarrhea, all of the following statements are correct EXCEPT:

Explanation

## Electrolyte Abnormalities in Acute Diarrhea ### Hypokalemia Pathophysiology **Key Point:** Potassium depletion in diarrhea occurs via: 1. **Fecal losses** — the primary mechanism (stool K^+^ concentration 20–30 mEq/L) 2. **Metabolic acidosis** — shifts K^+^ intracellularly in exchange for H^+^ (paradoxically worsens serum hypokalemia despite total body depletion) 3. **Aldosterone activation** — secondary to volume depletion increases renal K^+^ wasting This is why serum potassium may underestimate total body potassium depletion in diarrhea. ### Hyponatremia Management **Clinical Pearl:** Hyponatremia (Na^+^ 128 mEq/L) in acute diarrhea is typically **hypotonic** (dilutional), caused by: - Hypotonic stool losses (stool Na^+^ ~40–60 mEq/L, much less than plasma) - Replacement with hypotonic fluids (water, breast milk, dilute juices) - ADH release from volume depletion **Warning:** Rapid correction of hyponatremia (>10–12 mEq/L per 24 hours) risks **osmotic demyelination syndrome** and cerebral edema. Correct slowly over 48 hours using: - Isotonic saline (0.9% NaCl) initially - Gradual increase in serum sodium - Fluid restriction if ongoing hypotonic intake ### Zinc Supplementation: NO Contraindication in Electrolyte Abnormalities **High-Yield:** Zinc supplementation (10 mg/day for 10–14 days) is **NOT contraindicated** by electrolyte abnormalities. In fact: - Zinc is essential for intestinal epithelial repair and immune function - It should be started **immediately** in acute diarrhea, regardless of electrolyte status - Delaying zinc until electrolyte correction is incorrect and delays recovery - WHO/UNICEF guidelines make no exception for electrolyte abnormalities **Mnemonic: ZINC EARLY** — Zinc In Neonates/Children: Early administration Reduces Length of illness, Yields faster recovery ### Glucose-Sodium Cotransport **Key Point:** The sodium-glucose cotransporter (SGLT1) on the intestinal epithelium allows coupled absorption of glucose and sodium even in secretory diarrhea, because: - This transporter is **active transport** (not dependent on osmotic gradient) - It works independently of cAMP-mediated secretion - Low-osmolarity ORT (75 mEq/L Na^+^, 65 mmol/L glucose) exploits this mechanism - This is why ORT remains effective even in cholera and other secretory diarrheas ### Summary Table: Electrolyte Abnormalities in Diarrhea | Electrolyte | Mechanism | Management | |---|---|---| | Hypokalemia | Fecal losses + intracellular shift from acidosis | Oral/IV K^+^ replacement; correct acidosis | | Hyponatremia | Hypotonic losses + hypotonic fluid intake | Slow correction over 48 hrs; isotonic saline | | Hypochloremia | Fecal losses | Corrected with saline-based ORS | | Metabolic acidosis | Loss of bicarbonate in stool | Corrected by rehydration and tissue perfusion | [cite:Park 26e Ch 7; Harrison 21e Ch 143]