Etiology
Genetic Disease
- Carbonic Anhydrase I (CA-I) Deficiency/Alteration
- Ehlers-Danlos Syndrome (see Ehlers-Danlos Syndrome)
- Familial Type 1 Distal Renal Tubular Acidosis
- Autosomal Dominant
- Autosomal Recessive
- Hereditary Elliptocytosis (see Hereditary Elliptocytosis)
- Marfan Syndrome (see Marfan Syndrome)
- Medullary Cystic Disease: produces both distal RTA and proximal RTA
- Neuroaxonal Dystrophy
- Osteopetrosis
- Sickle Cell Disease (see Sickle Cell Disease)
- Wilson Disease (see Wilson Disease)
Tubulointerstitial Renal Disease
- Chronic Pyelonephritis
- Leprosy (see Leprosy)
- Obstructive Uropathy
- Renal Transplant Rejection (see Renal Transplant)
Nephrocalcinosis Syndromes
- Fabry Disease (see Fabry Disease)
- Hereditary Fructose Intolerance
- Hypercalcemia (see Hypercalcemia)
- Hyperthyroidism (see Hyperthyroidism)
- Milk Alkali Syndrome (see Milk Alkali Syndrome)
- Medullary Sponge Kidney
- Primary Hypercalciuria
- Primary Hyperoxaluria (see Primary Hyperoxaluria)
- Primary/Familial Hyperparathyroidism (see Hyperparathyroidism)
- Sarcoidosis (see Sarcoidosis)
- Vitamin D Intoxication (see Vitamin D)
Autoimmune Disease
- Chronic Active Hepatitis
- Hashimoto’s Thyroiditis (see Hashimoto’s Thyroiditis)
- Primary Biliary Cirrhosis (PBC) (see Primary Biliary Cirrhosis)
- Idiopathic Pulmonary Fibrosis (IPF) (see Idiopathic Pulmonary Fibrosis)
- Rheumatoid Arthritis (RA) (see Rheumatoid Arthritis)
- Sjogren’s Syndrome (see Sjogren’s Syndrome): produces both distal RTA and proximal RTA
- Systemic Lupus Erythematosus (SLE) (see Systemic Lupus Erythematosus)
- Vasculitis (see Vasculitis)
Hypergammaglobulinemic States
- Amyloidosis (see Amyloidosis): produces both distal RTA and proximal RTA
- Cryoglobulinemia (see Cryoglobulinemia)
- Multiple Myeloma (see Multiple Myeloma): produces both distal RTA and proximal RTA
Drugs/Toxins
- Amphotericin B (see Amphotericin)
- Cyclamate
- Ifosfamide (Ifex) (see Ifosfamide): produces both distal RTA and proximal RTA
- Lithium Carbonate (see Lithium)
- Toluene Intoxication (see Toluene)
Other
- Cirrhosis (see End-Stage Liver Disease)
- Human Immunodeficiency Virus (HIV)/AIDS (see Human Immunodeficiency Virus): possible etiology
- Idiopathic (Sporadic) Type 1 Distal Renal Tubular Acidosis
Physiology
- Impaired distal tubular H+ secretion/ excessive back-diffusion of H+ in collecting duct (by intercalated cells)
- Renal bicarbonate loss: bicarbonate is replaced by chloride (produces hyperchloremia)
Diagnosis
- Serum Potassium: hypokalemia
- Urine pH: >5.4
- Urine AG: (urine Na+ + urine K+) – (urine Cl-)
- Normal: -20 to -50 mEq/L
- Positive: due to decreased renal ammonium ion (NH4+) excretion, as NH4Cl
- NH4Cl Oral Load Test: patient is unable to decrease urine pH <5.4
Clinical Manifestations
Renal Manifestations
Non-Anion Gap Metabolic Acidosis (see Metabolic Acidosis-Normal Anion Gap)
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Treatment
- Potassium citrate or potassium bicarbonate: typical requirement is 1-2 mEq/kg/day
References
- The use of the urinary anion gap in the diagnosis of hyperchloremic metabolic acidosis. N Engl J Med 1988; 318 594-599
- A modified classification of metabolic acidosis: a pathophysiological approach. Nephron 1992; 60:129-133