Acidosis is acid intoxication due to faulty metabolism and elimination of acid chemicals.
A syndrome of persistent dehydration, hyperchloremia, hypokalemia, metabolic acidosis, and nephrocalcinosis, renal tubular acidosis (RTA) results from the kidney's inability to conserve bicarbonate. The prognosis is usually good but depends on the severity of renal damage that precedes treatment.
CAUSES
metabolic acidosis usually results from renal excretion of bicarbonate. However, metabolic acidosis associated with RTA results from a defect in the kidney's normal tubular acidification of urine. RTA occurs as distal RTA or proximal RTA.
Distal RTA
Type I RTA results from an inability of the distal tubule to secrete hydrogen ions against established gradient across the tubular membrane. This results in decreased excretion of titratable acids and ammonium, increased loos of potassium and bicarbonate in the urine, and systemic acidosis.
Prolonged acidosis causes mobilization of calcium from bone and eventually hypercalciuria (increased presence of calcium in the urine), predisposing to the formation of renal calculi (kidney stones).
Distal RTA may be classified as primary or secondary:
- Primary distal RTA may occur sporadically or through a hereditary defect and is most prevalent in females, older children, adolescents, and young adults.
- secondary distal RTA has been linked to many renal or systemic conditions. such as starvation, malnutrition, hepatic cirrhosis, and several genetically transmitted disorders.
Proximal RTA
type II RTA results from defective reabsorption of bicarbonate in the proximal tubule. This causes bicarbonate to flood the distal tubule, which normally secretes hydrogen ions, and leads to impaired formation of titratable acids and ammonium for excretion. Ultimately, metabolic acidosis results.
SIGNS & SYMPTOMS
In infants, RTA produces loss of appetite, vomiting, occasional fever, increased urination, dehydration, growth retardation, apathy, weakness, tissue wasting, constipation, nephrocalcinosis, and rickets.
In children and adults, RTA may lead to urinary tract infection, rickets, and growth problems. Possible complications of RTA include nephrocalcinosis and pyelonephritis.
TREATMENT
Supportive treatment for people with RTA requires replacement for those substances being abnormally excreted, especially bicarbonate. it may include sodium bicarbonate tablets or Shohl's solution to control acidosis, oral potassium for dangerously low potassium levels, and vitamin D for bone disease. If pyelonephritis occurs, treatment may include antibiotics as well.
Treatment for renal calculi secondary to nephrocalcinosis varies and may include supportive therapy until the calculi pass or until surgery for severe obstruction is performed.
see your doctor immediately if you notice blood in the urine or experience low abdominal or flank pain. If you have a low potassium level, eat foods with a high potassium content, such as bananas and baked potatoes. Orange juice is also high in potassium. Because RTA may be caused by a genetic defects, you should also seek genetic counseling or screening for this disorder.