It should be kept in mind that these are at best only temporizing measures and the potassium must be removed from the patient by the kidneys or through the GI tract or dialysis. Loop and thiazide diuretics increase potassium excretion in the urine in patients with normal or mild to moderately impaired renal function, particularly when combined with saline hydration (in appropriate patients) to maintain distal sodium delivery and flow. Kayexalate works in the GI tract by promoting the exchange of potassium for sodium along the gastrointestinal tract. Each gram of resin removes .5 to 1 meq of potassium in exchange for 2 to 3 meq of sodium. Significant amounts of calcium and magnesium also may be removed. Two newer agents, Patiromer and Zirconium have been found to be effective alternatives for treatment of hyperkalemia. Only Patiromer has received FDA approval. Patiromer is a nonabsorbable organic polymer that binds to potassium in the colon in exchange for calcium.
This ultrasound demonstrates a normal kidney by size and echogenicity. This is consistent with the presence of acute renal failure and not chronic renal disease. These patients tend to have a better chance of recovering normal renal function then a patient who has underlying renal disease, which would be manifested by increased echogenicity and small kidneys. This ultrasound also rules out stone disease and the likelihood that obstruction is responsible for the acute renal failure. It should be kept in mind that patients with renal obstruction might have low, normal or increased amounts of urine output due to a solute diuresis and for this reason one cannot make the diagnosis of obstruction on the basis of urine volume. Occasionally early obstruction or ureteral obstruction secondary to infiltrating tumors may not be seen on an ultrasound because the ureters will not be dilated. For this reason it is important to check the urine osmolality. This will be very low in patients that have obstruction because of damage to the distal nephron.