1. Type 1 RTA: distal tubule, error with H-K transporter in a-intercalated cells. Associated with severe acidosis due to inability to excrete H, and hypokalemia due to inability to re-absorb K. Easily treated with bicarbonate, children will often "outgrow" it. In adults, often due to autoimmune disease (sjogren's lupus) and can often be a presenting feature of the disease. In children, can be due to genetics (mutated transporter) or nephrotoxic drugs (ifosfamide).
2. Type 2 RTA: proximal tubule, error with Na-Bicarbonate transporter. Kidneys waste bicarbonate; Treatment is bicarbonate supplementation, but it's like filling a bucket with a leak in the bottom. Difficult to treat, often associated with significantly damaged tubules, often requires lifelong treatment. Sometimes associated with Fanconi's syndrome. In adults, often due to accumulation of immunoglobulin light chains (multiple myeloma), which are resistant to degradation by lysosomal enzymes of prox tubule cells and will thus accumulate there.
3. Type 4 RTA: distal tubule, error with aldosterone action; either aldosterone deficiency or resistance. Results in hyperkalemia (aldosterone causes loss of K). Treat with aldosterone-mimetic.
4. All cases of RTA will cause non-anion gap acidosis, since "the kidneys compensate for NaHCO3 loss by retaining NaCl in an attempt to preserve volume, with the net effect being a mEq-for-mEq exchange of chloride for bicarbonate and no change in the AG." -uptodate
5. Common presenting symptoms of RTA in children: failure to thrive, kidney stones, paralysis/weakness (from electrolyte abnormalities), tachypnea.
6. Giving maintenance fluids: if you give isotonic maintenance fluids, people will eventually become edematous. People with normal kidneys will naturally pull back the vast majority of the sodium in their urine, leading water to go with it. Water follows salt, so the more salt you give the more water you give. Additionally, the stress response (2/2 pain, stress from being in the hospital) leads to ADH secretion, which pulls back more water and leads patients to become volume overloaded. If you want to avoid this, you give hypotonic maintenance fluids, so that there is less salt in their system. However, when you do this, you risk diluting out their serum and giving them hyponatremia.
-In adults, who often are suffering from some degree of heart or renal failure, you don't want to volume overload them, so you tend to give more hypotonic solutions (0.5NS, for example)
-In children, who have healthier hearts, you're more worried about hyponatremia, so you give isotonic solutions (0.9 NS, or LR).
7. Insensible fluid losses: 400-600 ml/m2/day. Max Na replenishment rate: 10 mEq/day
8. if you're really worried about edema/third spacing, you can give someone albumin to pull all the fluid out of their third spaces, and then chase them with lasix.
9. Most common cause of congenital blindness in utero: CMV, then rubella. Most common cause of preventable blindness in infants: chlamydia. Erythromycin eye drops cover GC, but not chlamydia well. if you're worried about chlamydia, do systemic erythromycin.
10. Treatment for moms with GBS: first line penicillin (0% resistance). Next line clinda (15% resistance). If resistant to clinda, give vanc. Side effects of ceftriaxone (biliary sludging/cholecystitis), erythromycin (pyloric stenosis), doxycycline (stained teeth/bones since it's a Ca chelator)