70 Rhabdomyolysis & myoglobin

KYJ  70 Rhabdomyolysis

Was asked in class what Rhabdomyolysis was today. So I thought that would be a good KYJ topic.

Rhabdo = stripy
Myo = muscle
Lysis = destroy

Rhabdomyolysis is skeletal muscle damage.
In cases of crush injury, hyperthermia, over extreme muscle exercise, and electrocution, it is probable that muscle tissue can be injured.

Muscle yields a high concentration of proteins and electrolytes that are released when Muscle cells are damaged.

Myoglobin
Myoglobin is the large red protein in muscle, which transports oxygen.  It is essentially the same as haemoglobin in the red blood cell, in that it carries oxygen.

When injured (rhabdomyolysis), muscle cells spill or leak this from their cytoplasm.  It is picked up in lymphatic fluid and extruded into blood.  As it is filtered out in urine, it shows up by making the urine appear blood stained.  Urine will test positive for blood and is called myoglobinuria.  The sad consequence is renal failure as myoglobin clogs up the renal tubules.

Potassium
Potassium (K+) is the principle intra cellular cation (positive charged electrolyte).  It exists in low quantities in blood, but high concentration inside cells.
As muscle cells are damaged, it leaches out into the blood causing a dangerous elevation in serum potassium (hyperkalaemia). If too high, it becomes cardiotoxic.  Spiking potassium after crush injuries is the likely cause of sudden cardiac arrest in the minutes following rescue.

Creatine Kinase
CK is an enzyme that is used in the process of converting glucose to energy in muscle cells. When muscles are subject to rhabdomyolysis, they release this enzyme which may be detected in blood and used as a gauge as to how severe the tissue damage is.

Rhabdomyolysis alone is a deadly killer. It's cardiac effects and kidney damage are sinister sequelae of a large injury to muscles.