Sodium and water homeostasis in children with shigellosis

Area of Science:

• Pediatric Infectious Diseases
• Renal Physiology
• Endocrinology

Background:

• Shigellosis is associated with higher mortality in hyponatremic children in Bangladesh.
• Hyponatremia (serum sodium < 130 mmol/L) is a critical concern in pediatric shigellosis.
• Understanding the impact on renal hemodynamics and homeostasis is vital for management.

Purpose of the Study:

• To investigate the effects of Shigella dysenteriae type I infection on renal hemodynamics.
• To analyze sodium and water homeostasis in hyponatremic (HN) versus normonatremic (NN) children before treatment.
• To explore the roles of plasma renin, aldosterone, and anti-diuretic hormone (ADH).

Main Methods:

• Studied 21 moderately ill children with Shigella dysenteriae type I.
• Measured glomerular filtration rate (GFR) using inulin and iohexol clearances.
• Assessed effective renal plasma flow (ERPF) via para-aminohippuric acid clearance.
• Quantified plasma renin, aldosterone, and ADH levels.

Main Results:

• HN children had higher hemoglobin and hematocrit than NN children.
• Inverse correlation between serum sodium and hemoglobin; direct correlation with urinary sodium and chloride.
• Direct correlations observed between aldosterone and hemoglobin, renin and systolic blood pressure.
• Inverse correlation between aldosterone and serum sodium; normal GFR and ERPF.
• Detectable ADH levels were present in both groups despite low serum osmolality.

Conclusions:

• Hyponatremia in shigellosis appears multifactorial.
• Normal renal function suggests hyponatremia is not due to volume expansion from reduced GFR.
• Inappropriate or physiological increase in ADH secretion may play a significant role.
• Increased fecal sodium losses could also contribute to hyponatremia.