Can cause chronic [[Blood gas#Metabolic acidosis|metabolic acidosis]] > a group of conditions with an impaired ability to: > - *secrete H+* in the distal convoluted tubule or > - *absorb HCO3-* in the proximal convoluted tubule **features** - [[hypokalemia|hypo-k]] (except for type 4) - nephrocalcinosis - rickets or osteomalacia - [[Blood gas#NAGMA]] # ​most common causes in ED - chronic renal diseases - ibuprofen abuse - [[Toluene toxicity]] - look for hypo-k and [[rhabdomyolysis]] - Heavy metal toxicity eg [[Iron overdose]] or [[Lead]] - [[​Lithium Toxicity|lithium]] - Excess spironolactone (look for hyper-k) # type 1 - distal - distal, impaired H+ secretion - inability to acidify the urine to a pH of <5.5 - Leads to NAGMA acidemia - Low K reabsorption → hypokalemia - [[Hypocalcemia|hypocalcaemia]] - hyperchloraemia - contributes to stone formation **causes** - amphoterecin - severe hypokalemia - [[​Lithium Toxicity|lithium]] - sjogren's syndrome - SLE - urinary obstruction - Hereditary # type 2 - proximal - proximal - impaired renal HCO3 resorption in *proximal tubule* **causes** - fanconi syndrome - Look for osteomalacia or rickets (bone demineralization) due to *phosphate wasting* - urinate out phosphate - Glycosuria - other genetic diseases - myeloma # type 3 - rare Combined proximal and distal # type 4 - absolute hypoaldosteronism or aldosterone insensitivity - Type 4 RTA is not actually a tubular disorder at all nor does it have a clinical syndrome similar to the other types of RTA described above. It was included in the classification of renal tubular acidoses as it is associated with a mild [[Blood gas#NAGMA]] due to a _physiological_ reduction in proximal tubular ammonium excretion - defective ammonia production → reduced urine buffering capacity - Secondary to hypoaldosteronism - ==[[hyperkalemia]] is the cardinal feature== **causes** - aldosterone deficiency - glucocorticoid insufficiency - loss of renal cell mas > 70% - urinary tract obstruction - ==Drugs causing aldosterone resistance== - NSAIDS - ACE-i - ARBs - spironolactone # management - treat type 1 RTA with citrated [[HCO3 therapy]] decreases systemic acidosis - may prevent renal calculi, progression of renal disease, secondary bone disease