Drug-Induced Rhabdomyolysis

(Drug-Induced) Rhabdomyolysis

Learning Objectives

1. Identify the etiology of rhabdomyolysis

2. Recognize the presentation and clinical manifestations of the syndrome as

it pertains to drug-induced rhabdomyolysis

3. Describe the pathogenesis of the syndrome

4. Understand the natural history of an untreated case of rhabdomyolysis

5. Recognize what drugs have the potential for causing rhabdomyolysis

6. Discuss the diagnostic testing and interventions applicable for treating

rhabdomyolysis

Quiz Questions

Quiz Answers

1. Describe the etiology of rhabdomyolysis.

c. Events that follow in response to the toxic insult of muscle tissue

2. List three clinical scenarios where rhabdomyolysis may develop.

d. All of the above

3. Identify drugs that may cause rhabdomyolysis.

a. Acetaminophen

b. Diazepam

c. Vasopressin

d. Prednisone

f. Caffeine

4. Name three elements that are released due to muscle injury.

c. Myoglobin, Phosphate, Potassium

5. What level must the myoglobin reach in the blood before it is found in the urine?

d. 230 mg/L

6. Identify the primary intervention for drug-induced rhabdomyolysis.

c. Administering IV normal saline

Process

1. Describe the etiology of rhabdomyolysis.

a. An autoimmune response to a viral infection

b. A disease acquired after being bitten by an infected squirrel

c. Events that follow in response to the toxic insult of muscle tissue

d. All of the above

2. List three clinical scenarios where rhabdomyolysis may develop.

a. MVA, Disney Marathon, Post-propofol anesthesia

b. Alcoholic, Treatment for hyperlipidemia, Third-degree burns

c. Cocaine abuse, Lightning strike, Erythromycin treatment

d. All of the above

3. Identify drugs that may cause rhabdomyolysis. (Choose all that apply)

a. Acetaminophen

b. Diazepam

c. Vasopressin

d. Prednisone

e. Ranitidine

f. Caffeine

4. Name three elements that are released due to muscle injury.

a. Sodium, Potassium, Hydrogen ions

b. Potassium, Vitamin K, Histamine

c. Myoglobin, Phosphate, Potassium

d. Myoglobin, Sodium, Creatinine

5. What level must the myoglobin reach in the blood before it is found in the urine?

a. 540 mg/L

b. 665 mg/L

c. 90 mg/L

d. 230 mg/L

6. Identify the primary intervention for drug-induced rhabdomyolysis.

a. External cooling

b. Administering sedatives

c. Administering IV normal saline

d. Maintaining good oral hygiene

Pathogenesis/Natural History

Muscle injury and/or degradation leads to the release of AST, ALT, LDH, CK isoenzymes and the protein myoglobin into the vascular system

Myoglobin over 230 mg/L will filtrate through the glomeruli, producing myoglobinuria seen as blood in the urine dipstick - urine appears "tea-colored"

Myoglobin accumulates in the glomeruli, restricting the glomerular filtration rate

The elevated blood creatinine level reflects the effect of the myoglobin molecules interfering with the function of the glomeruli in the kidneys

Muscle cell membrane damage releases intracellular potassium causing the hyperkalemia and phosphorus causing hyperphosphatemia

In the early stages of rhabdomyolysis, hypocalcemia is caused by the buildup of calcium in necrotizing muscle tissue

Later, with calcium being released by the same necrotizing muscle tissue, the patient will experience hypercalcemia

And furthermore...

If left unchecked, things can get really ugly...

• intrinsic renal failure becomes acute kidney necrosis which can lead to acute renal failure
• electrolyte imbalance may lead to heart dysrhythmias such as complete heart block, ventricular fibrillation, and asystole (and that means dead)

Drug-Induced Rhabdomyolysis Patho Map

Input 1

Definition/Etiology

Direct toxic insult to musculoskeletal fibers resulting in the disintegration of the muscle and the subsequent release of muscle cell components into blood vessels

Output

Input 2

Diagnostic Test Results

Patient Presentation/Clinical Manifestation

• The elevated CK and liver enzymes, skeletal muscle contraction, hyperthermia, elevated heart rate and blood pressure, myoglobinuria, hypocalcemia, hyperkalemia and the elevated creatinine and phosphate levels were all indicative of rhabdomyolysis
• The patient's erratic, disoriented behaviors as well as her hallucinations were suggestive of controlled substance ingestion

An uncooperative, disoriented, and combative

28-year-old female patient is brought to the ER and placed in five-point leather restraints. She is incoherent and seems to be having auditory and visual hallucinations. Her temperature is 100.5 F,

HR 120 bpm, and BP 150/100. She appears to have some tetany in her right hand. Her urine was noted to be

“tea-colored” with 4+ for blood but no RBC on microscopy. Client is also positive for cocaine and ecstasy.

Management

• Hydrate! Give IV normal saline to increase urine output and "flush" the system of the toxic agents and myoglobin
• External cooling measures/muscle relaxants to decrease body temperature
• Infuse sodium bicarbonate and dextrose/insulin to treat increased urine acidity and hyperkalemia
• Monitor blood urea nitrogen, creatinine, electrolytes
• EKG monitoring for dysrhythmias

Input 3

Pertinent Clinical Findings

------

Be Aware...

• Drug-induced rhabomyolysis is caused by the legal/illicit substances such as those found on the patient's laboratory blood work and urinalysis; alcohol, cocaine, and MDMA (Ecstasy)
• Myoglobinuria is part of rhabdomyolysis as the myoglobin released by the necrotic muscle tissues overwhelm the glomeruli and filter into the renal tubules

What else causes rhabdomyolysis other than illicit drugs or alcohol??

Things like...

• crushing injuries - trauma
• muscle overexertion - like from running a marathon
• muscle compression - compartment syndrome
• malignant hyperthermia - after anesthesia
• infections/inflammation - think Epstein-Barr
• "harmless" drugs like statins/erythromycin - beware!

But hey...there's more!!

Drug-Induced Rhabdomyolysis

Shelley Alvarez

University of Tampa

If you have never experienced a Prezi...

hold on, this IS a bumpy ride!

References

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