TOC  |  Lytes  | Acid-Base Disturbances

METABOLIC ACIDOSIS: WITH Normal ANION GAP (Na - Cl - HCO₃ = 12-14)/
HYPERCHLOREMIC ACIDOSIS

1. Renal tubular acidosis
a. RTA - Distal Type I
Diagnosis:
Dx may be suggested by persistent relatively alkaline urine pH>6, hypokalemia, nephrocalcinosis,
or nephrolithiasis, & hyperchloremic metabolic acidosis with normal anion gap.
Screening test with the second voided morning urine following an overnight fast & ingestion of a small water load. A urine pH < 6 is good evidence against distal RTA.

Confirm diagnosis with acid loading test. If the urine pH does not drop < 5.4 during a 6 8 hr period after the ingestion of 0.1 gm of NH4Cl/kg, this establish the dx of distal RTA.

b. RTA - Proximal Type II
Diagnosis:
Dx is suggested by large bicarbonaturia, hypovolemia, hypokalemia, & Hyperchloremic metabolic acidosis. Urine pH may be 7.0 7.8 in pts with plasma HCO3 of 20-24 meq/l, but may be 5.4 if plasma HCO3 is 16 meq/l.

2. Uremic acidosis (early)

3. Intestinal loss of HCO3 or organic acid anions:  Diarrhea, Pancreatic fistula

4. Ureteroenterostomy

5. Drugs: Acetazolamide (Diamox), Sulfamylon, Cholestyramine (Questran), Acidifying agents: NH4Cl, oral CaCl2, arginine HCl, lysine HCl; Aldactone in cirrhotic pts

6. Rapid IV hydration

7. Correction of respiratory alkalosis

8. Hyperalimentation