Morning Report: 7/31/2012

Today’s morning report comes courtesy of Dr. Lau.

It begins with the following case presentation:

22 yo m with no pmh BIBEMS for syncope c/o nausea, fatigue, and generalized myalgias.

Pt states just returned from a trip to Miami where he was enrolled at a training bootcamp for 2 days and was sunburnt on the beach.

Exam:

Vitals stable, afebrile

Alert and oriented

Mostly 1st degree burns on chest wall

Any thoughts so far?

Keep reading below for lab results and the conclusion:

Labs:

CK: 26000

UA: +myoglobin

K, Cr normal

Dx: Rhabdomyolysis

– Disruption of calcium homeostasis of muscle cell

Direct cell membrane damage
- Trauma, hereditary, biochemical -> direct Ca influx
ATP depletion
- Increased intracell Ca by disrupting Na/K ATPase -> triggers apoptosis, cell death

– Most common presentations

– Less common

Also remember that many pharmaceuticals, eg. Statins, neuroleptics, antihistamines…
Crush injuries, compartment syndrome
Excessive muscular activity (marathon runners, prisoners wanting a hospital vacation does 2000 squats to get rhabdo, now boon of “boot camps” and crossfit)
….

– Labs

Elevated CK
Myoglobin in urine
HyperK, Hyperphos, early hypoCa, late hyperCa
Increased BUN and Cr but decreased BUN:Cr due to release of Cr from muscle, normal 10:1, can be 5:1 in rhabdo

– EKG – look for signs of hyper K

– Early complications

Electrolyte abnormalities -> dysrhymias
Hypovolemia – likely already dehydrated, but damaged muscle -> fluid sequestration -> intravasc volume depletion

– Late

– Treat

Aggressive volume expansion
- Delayed fluid resus -> develop acute renal failure (in fact, pts in mass casualty events – initiate fluid resus before complete extrication)
Urine alkalinization controversial
- Based on animal data that myoglobin precipitation increased in acidic urine
- Not shown to impact outcomes in humans
- NS with 1 amp sodium bicarb at 100 ml/h – but look out for hypoCa
Mannitol controversial, no benefits shown – osmotic diuretic thought to increase urine flow therefore reduce myoglobin cast obstruction of renal tubules
Furosemide if pt is oliguric but must only do so after assuring adequate intravasc volume
Renal replacement therapy if uncorrectable metabolic acidosis, life-threatening hyperK, renal failure