Renal Tubular Functions: Best article 2025

1. Proximal Tubule Functions

• Reabsorption of:
• Sodium (Na+), Potassium (K+), Chloride (Cl-), and Bicarbonate (HCO3−)
• Glucose, amino acids, phosphate, and uric acid
• Secretion of organic acids and bases
• Production of ammonia (NH3)

2. Loop of Henle Functions

• Reabsorption of water in the descending limb
• Reabsorption of Na+, Cl-, and K+ in the ascending limb
• Establishment of the medullary concentration gradient

3. Distal Tubule and Collecting Duct Functions

• Reabsorption of Na+ and secretion of K+ and H+
• Fine-tuning of water reabsorption under the influence of antidiuretic hormone (ADH)
• Acid-base regulation

Tests to Evaluate Proximal Tubular Disorders

1. Bicarbonate Reabsorption:

• Venous Blood Gas (VBG): Low serum bicarbonate (metabolic acidosis).
• Urinary pH: Normal or mildly reduced (despite acidosis).

1. Glucose Reabsorption:

• Urine Glucose Testing: Positive for glucose despite normal blood glucose levels (renal glycosuria).

1. Phosphate Reabsorption:

• Serum Phosphate: Hypophosphatemia.
• Urine Phosphate: Increased urinary excretion of phosphate.

1. Amino Acid Reabsorption:

• Aminoaciduria: Detected via urine chromatography.

1. Urinary Concentration Capacity:

• Fractional Excretion of Solutes: Elevated values for solutes like sodium, uric acid, and potassium.

Treatment of Proximal Renal Tubular Acidosis (pRTA) in Children

1. Alkali Therapy:

• Sodium bicarbonate or potassium citrate to correct acidosis.
• Target serum bicarbonate: 20-22 mEq/L.

1. Potassium Supplementation:

• Correct hypokalemia with oral potassium chloride or potassium citrate.

1. Phosphate Supplementation (if necessary):

• To treat hypophosphatemia if present.

1. Vitamin D and Calcium:

• If rickets or osteomalacia is present, provide calcitriol and calcium.

1. Dietary Management:

• Adequate hydration and a diet rich in fruits and vegetables to maintain acid-base balance.

1. “Proximal renal tubular acidosis treatment in children”
2. “Tests to diagnose proximal tubule dysfunction”
3. “Renal tubular acidosis pediatric management guidelines”
4. “Role of bicarbonate in treating pRTA in children”
5. “Symptoms of proximal tubule renal disorder in kids”