Pigment Nephropathy and Rhabdomyolysis Flashcards
what happens in muscle crush injury with the kidneys?
there’s an increase in extracellular fluid volume within the damaged tissue
see release in myoglobin to and this can decrease renal perfusion due to extracellular fluid segrestration and result in acute kidney injury.
how to treat pts with crush injury?
initial goal is to quickly restore extracellular fluid volume and renal perfusion.
HIgh urine outflow also helps to wash out obstructing pigment casts. Do this with saline. at 1-2L per hour for first two hours with subsequent amounts based on labs.
What is a potential side effect of rapid fluid resuscitation with crush injury in attempt to protect kidneys?
pulmonary edema and peripheral nerve entrapment from a compartment syndrome due to muscle swelling that is accelerated by fluid retention.
DO we use LR for crush injury?
no because it contains K and can cause hyperkalemia?
do we use mannitol for crush injury to protect kidneys?
no, only in severe cases and it needs close monitoring of labs and serum osmolality
Do we use sodium bicarb for treatment of pigment induced nephropathy related to crush injury?
no.
Lab features of rhabdomyolysis:
elevated CK >10K generally above
red to brown urine with positive blood and no RBCs (myoglobinuria)
Electrolytes changes: hyperK, hyperphosphatemia, hyperuricemia due to intracellular electrolyte release
Hypocalcemia and dehydration to influx of calcium and intravascular fluid into injured muscles
Cr AKI due to tubular injury from myoglobulinuria
FENA can be falsely low
can get rhabdomyolysis from
seizure
excessive exercise
drug use PCP
Why is FENA falsely low in rhabdomyolysis?
AKI results from abundance of filtered heme pigment leading to acute tubular necrosis and causes <1% FENA because despite intrinsic renal injury due to renal vasoconstriction,
hyperkalemia, hyperphosphatemia and hyperuricemia from muscle lysis are disproportionate to degree of renal failure
