2.6.2. Rhabdo Flashcards
What is the term ER (not Emergency Room)?
Exertional Rhabdomyolysis
What is Exertional Rhabdomyolysis?
Condition or syndrome of skeletal muscle breakdown with release of myocyte contents into the circulation
What determines the lethality of Exertional Rhabdomyolysis?
Risk of developing metabolic abnormalities and acute renal failure are primary determinants of morbidity and mortality
How does Myolysis come about?
Myolysis may arise from a variety of stresses that cause injury to muscle tissue
Common causes of Rhabdo
- Unaccustomed exercises (new routine, etc)
- Eccentric exercise more damaging to muscle fibers than concentric exercise
- More common in Type 2 muscle fibers (anaerobic, fast twitch fibers)
- Sudden increase in volume or intensity of exercise bouts
- TIMED exercises (“beating the clock”)
How long after a strong exertion do symptoms show up?
Symptoms precipitated by strenuous exercise or exertion usually 24 to 48 hrs prior to presentation
Most common muscle injury associated with Rhabdo?
Direct injury appears to be predominantly to Type II (white, anaerobic, fast twitch) muscle fibers
How can ATP cause Rhabdo?
Impairment of either ATP production or utilization can cause Rhabdo
Muscle injury results in the release of what into the bloodstream?
Muscle injury results in release of potassium, uric acid, calcium phosphate, myoglobin, and muscle enzymes (CK, LDH, AST, ALT) into plasma
There are many causes of Rhabdo, but what do they all TYPICALLY lead to after the decrease in intracellular ATP?
After the reduction in ATP, there is a Calcium influx into the sarcoplasmic reticulum, which, like a reperfusion injury and compartment syndrome, leads to a mess of increases like:
- Free radicals
- Calcium dependent phosphorylases
- Nucleases
- Proteases
- Local PMN Cells
Which leads to rhabdo
Diagnosis for Rhabdo is different amongst many diagnosticians, but what do we know about diagnosing rhabdo? What do we see in the labs?
- importantly, Creatine Kinase levels are well above normal limits
- BUT, normal limits can vary depending on the Pt population (men vs women, athletes vs non-athletes, white/African-American/Asian/etc
- HIGH CK LEVELS DO NOT AUTOMATICALLY MEAN YOU HAVE RHABDO, OR EVEN IMPAIRED ABILITY
Glad we cleared that up.
There are may factors that can put people at risk for getting Acute Rhabdo. What are four conditions metabolically that can lead to Rhabdo sooner rather than later, and how do these patients typically present to the clinic?
Hallmarks of clinical presentation are myalgias, cramping, and exercise intolerance
- Myoadenylate Deaminase Deficiency
- Glycogen Storage Disease
- Fatty Oxidation Defects
- Mitochondrial Myopathies
Describe the “High Risk” warrior athlete.
- Delayed clinical recovery (more than a week) when activity has been restricted
- Persistent CK elevation despite 4 weeks at rest
- ER complicated by acute renal failure of any degree
- Muscle injury after low to moderate workload
When we need a referral for a rhabdo expert, they will typically request an EIMP, an Exercise intolerance mutation profile. What are the three conditions that often point to rhabdo?
Carnitine Palmitoyltransferase II Deficiency
Myophosphorylase Deficiency
Myoadenylate Deaminase Deficiency
What three SNPs are associated with ER?
CKMM Ncol, ACTN3 R577X, and MYLK C37885A.
