Myoglobinuria secondary to myonecrosis is a proven cause of
renal failure, especially in
critically ill patients. Physiologic
amputation or cryoamputation has been used at our institution for the past two decades as a safe and effective treatment for lower extremity
infection, intractable rest
pain, and irreversible myonecrosis. We retrospectively studied five
critically ill patients with myonecrosis of lower extremities associated with
myoglobinuria. The etiology of myonecrosis included preexisting
peripheral vascular disease or
crush injury to the lower extremities. It was determined that all five patients were too ill to undergo emergency
amputation.
Myoglobinuria was documented in all five patients and cleared within 24 hours of physiologic
amputation in four patients. All five patients had elevated
creatine phosphokinase levels (mean 20,270 mU/mL, range 12,090 to 43,164 mU/mL) that significantly decreased within 48 hours of physiologic
amputation (mean 6,488 mU/mL, range 2,250 to 13,580 mU/mL).
Mechanical ventilation and cardiovascular support were required in four patients. All patients had transient episodes of
renal insufficiency with two progressing to anuric
renal failure and requiring dialysis. One patient's
renal failure resolved after 56 days, but the other patient died of a
cerebrovascular accident 22 days after initiation of physiologic
amputation. The mean duration of physiologic
amputation was 15.6 days (range 5 to 32 days) with no significant complication due to physiologic
amputation. All five patients had
surgical amputation successfully. Three patients survived. The two deaths in the study were due to a
cerebrovascular accident in one patient and a
cardiopulmonary arrest in another. Physiologic
amputation is a treatment option that halts myonecrosis, prevents
myoglobinuria, and lessens the risk of associated
acute renal failure. Physiologic
amputation may be appropriately used in patients with
myoglobinuria due to extremity myonecrosis who are deemed too
critically ill to survive emergency
amputation.