rhabdomyolysis -registar teaching (9-10-12)b
DESCRIPTION
An overview of the management of Rhabdomyolysis, put together for the weekly Emergency Medicine registrar teaching session at Wollongong Hospital ED. Information in the presentation is from both the journals and medicine 2.0 (and in particular "FOAMed" -the free open access medical education network that aims to improve sharing of medical education resources through the web). Enjoy. @trainthetrainerTRANSCRIPT
Bishan Rajapakse – ED Registrar
Wollongong Hospital ED Reg teaching - 3/10/12
Rhabdomyolysis
Image courtesy of Dr Carl Oller https://vimeo.com/34408361
Rhabdomyolysis - Overview
Rhabdomyolysis in ACEM fellowship curriculum
Clinical Case – ‘teaser’ “Rhabdo facts”
Epidemiology, causes, pathophys &management
Clinical Cases – ‘pleaser’ Discussion Summary – take home points
ACEM fellowship syllabus
7-10% of ARF is 2˚ to Rhabdo
Case 1 – ‘Young crush’
26yo male Crush injury to R arm, 4x4 rolled back onto R arm
whilst under car Posterior compartment R Arm bruised and swollen Numbness and paraesthesia Suspected brachial plexus, CT Neck unremarkable
Labs results in resus (16/9/12 19:36)
Ph 6.92, Lactate 21, Cr 96 CK 419
Urine dipstick – Haematuria ++ Urine myoglobinuria not ordered
What do you think?
Is Rhabdomyolysis present? How do we make the diagnosis? What are the key features?
If it is Rhabdomyolysis? What is the management? What are his risks of ARF & death?
Progress
2nd CK 4 hours later CK 2,353 U/L
Admitted under trauma surgery Aggressive fluids, good UO
Serial CKs 17/9/12
03:11 – 3,999 U/L 06:00 – 4,604 U/L 14:30 – 6,275 U/L, Na 142, K 4.2, Ur 5.4, Cr 96
Pain and paraesthesia improving day 2 Patient discharged against medical advice!!
Rhabdomyolysis Rhabdmyolysis = ‘destruction of striated muscle’
Muscle breakdown and necrosis, Leaking of intracellular constituents into Circulation & ECF
Severity Ranges from Asymptomatic illness (with mild CK) to life threatening
condition extreme CK, Electrolyte imbalances, ARF & DIC
Causes Most commonly – muscular trauma Less commonly – muscle enzyme deficiencies, electrolyte abnormalities
Presentation Limb weakness, myalgia, swelling and tea coloured urine Commonly assoc with myoglobinuria, if severe can cause ARF
Investigations - CK >5,000 indicates serious muscle injury Management
ALS (airway breathing & circulation) Followed by measures to preserve renal function=vigorous hydration Use of alkalysing agents and osmotic diuretic – common by unproven
benefitHuerta-Alardin A, Varon J, Marik P. Bench-to-bedside review: Rhabdomyolysis -- an overview for clinicians. Critical Care. 2005;9(15774072):158-169.
Rhabdomyolysis - epidemiology Seen in 85% of patients with traumatic
injury Common in Earthquakes Acute Kidney injury in 10-50%
7-80% mortality Outcome generally good, but…
Co-existing valculopathy – mortality 32% In ICU patients – 22% mortality if RF
absent, 59% if RF present
Categories of cause
Physical Trauma (Crush syndrome) Exertion (strenuous exercise, siezure, AWS) Muscle hypoxia (limb compression, prolonged
immobilisation or LOC, major artery occlusion) Non Physical
Genetic defects (glycolysis or glyconeogenesis) Infections (legionella, malaria, herpes) Body temp changes Metabolic and electrolyte disorders (Na,K) Drugs and toxins (cocaine, statins) Endocrine/Autoimmune causes (polymyositis) Idiopathic
Clinical Illustrations
Dengue viral myositis 17 yo boy, fever and myalgia Day 4 developed oliguria, CK 60,000 (rpt 90,000) Reduced Calcium, elevated Phospate Oliguria and refractory hypotension – leading to
death Viral infections Rhabdomyolyis
Young male, heroin OD Elevated CK, Hyperkalaemia, Hypocalcaemia,
Sunderalingam et al “Dengue viral myositis complicated with rhabdomyolyis and super infection of methicillin resistant Staphylococcus aureus” awaiting publication
Pathophysiology
Method (and mechanism) of cellular destruction Direct injury to cell membrane
(crushing, tearing, dissolving) Muscle cell hypoxia leading to depletion ATP
(Anaerobic conditions, shock states, vascular occlusion and tissue compression)
Electrolyte disturbance disrupting the Na/K
pump (K :vomiting diarrhoea, extensive diuresis, Na: water intoxication)
Pathophysiology
Huerta-Alardin A, Varon J, Marik P. Bench-to-bedside review: Rhabdomyolysis -- an overview for clinicians. Critical Care. 2005;9(15774072):158-169.
How does Myoglobin cause ARF?
Perutz (Hb), Kendrick (Myoglobin)
Myoglobin
Haemoglobin
Myoglobinuric ARF
2 Cruicial Factors-Hypovolaemia/dehydration-Aciduria
ARF
Haem protein toxicity-Renal vasoconstriction-Diminished renal circulation-Intraluminal cast formation & direct haem protein-induced cytotoxicity
“in absence of hypovolaemia & aciduria heme proteins have minimal nephrotoxic effects”
Cast formation enhanced by urine Ph
It is suggested that ARF is caused by tubular obstruction
Pigmented Cast formation
The New England journal of medicine. 2009;361(19571284):62-72.
Investigations
CK levels >5000 U/L related to ARF (norm 45-260) Rises within 12 hrs, peak 1-3 days, declines 3-5days post muscle
injury After peak drops by 40% per day (T ½ 1.5d)
Myoglobinuria Urine dipstick positive for “blood” no red bood cells in urine sediment
Electrolytes K+, PO4, Uric acid, LDH, ALT, AST, carbonic anhydrase III Ca++, (initially low as moves into cells, may increase later)
Coagulation studies DIC may develop
Tox screen Etoh commonly associated with diagnosis Heroin and other illicit drugs
Urinalysis
Management
Advance Life Support Aggressive fluid therapy Urinary Alkalinisation +/-Mannitol Follow up CK and Electrolytes If suspect ARF
Cardiac monitoring Dialysis if necessary
Commonly used but controversial-Little clinical evidence
-Rationale “preserving urine flow in ARF may reduce damage”
-Useful if become fluid overloaded whilst being treated for Rhabdomyolysis
Case 3 – Could it be renal colic
65 year-old male presenting with right-sided flank pain radiating to the groin. The following CT scan was taken to confirm a presumed diagnosis of renal colic:
http://lifeinthefastlane.com/2009/12/renal-riddle-001/
CT scan
-Right sided retro peritoneal blood- AAA
Patient went for emergency AAA repair
Routine post op biochemistry
• increased urea and creatinine (with urea-to-creatinine ratio)• hyperphosphataemia, hypocalcaemia, hyperkalaemia • increased CK (usually to greater than 40,000)
http://lifeinthefastlane.com/2009/12/renal-riddle-001/
Rhabdomyolysis - treatment
aggressively correct hypovolaemia Target UO 2-3ml/kg/hr
Monitor K closely and treat hypokalaemia Alternate N/Saline with 1L litre of D5W
Avoid K & lactate containing solutions 100mmol of HCO3 if urine pH <6.5
“Consider” mannitol, up to 200g/day, not > 800g total dose.
Consider haemodyalysis if resistant hyperkalemia of more than 6.5mmol/L
Bosch X, Poch E, Grau JM. Rhabdomyolysis and acute kidney injury. The New England journal of medicine. 2009;361(19571284):62-72.
Hyperkalaemia (>5.5) in Rhabdo Check K every 4 hours when CK>60,000
Treat hyperkalaemia aggressively ECG
CaCl or CaGluconate Consider cardiac monitoring if K>6 Check plasma Calcium (aggravates hyperK)
K>6 1) Insulin and glucose, Salbutamol, 2) NaHCO3 if acidaemia (may worsen HypoCa, not efficacious as
no1 above) Optional - Remove potassium
Resins (sodium polystyrene sulfonate) Haemodialysis Loop diuretics (only once fluid level has been expanded
The New England journal of medicine. 2009;361(19571284):62-72.
Summary
Rhabdomyolysis – muslce necrosis Limb weakness, myalgia, swelling and tea coloured
urine Can be life threatening, common cause of ARF (7-10%)
Multiple causes – Physical and Non Physical Most commonly crush injury & immobility Can be drugs, tox
CK rise >5,000 Rx – Vigorous hydration – protect kidneys
Monitor electrolytes & correct hyperkalaemia Alkalinisation if Urine ph<6.5, Mannitol if fluid overload
References/Acknowledgements Critical Care
Huerta-Alardin A, Varon J, Marik P. Bench-to-bedside review: Rhabdomyolysis -- an overview for clinicians. Critical Care. 2005;9(15774072):158-169.
NEJM Bosch X, Poch E, Grau JM. Rhabdomyolysis and acute kidney injury. The New England
journal of medicine. 2009;361(19571284):62-72.
LTFL Paul Young (Intensivist Wellington, NZ) http://lifeinthefastlane.com/2009/12/renal-riddle-
001/
Free EM talks (Joe Lex) Garry Gaddis (Orthopaedic Surgeon) – talk “Rabdomyolysis & compartment syndrome” Cancun
Trauma conference 2008 (http://freeemergencytalks.net/2010/04/gary-gaddis-rhabdomyolysis-and-compartment-syndrome/)
Personal discussion/case reports unpublished data Darren Roberts (Clinical Pharm and Tox, UK) Vinothan Sunderalingam (Physician Trainee, Sri Lanka) Jorge Sesperz (Trauma researcher)
Wollongong ED Reg Facebook group
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Please join up today!
http://www.facebook.com/
groups/131728460307304/
And do start commenting –
remember – it’s only “us”
And don’t forget “Free EM talks – rock!!”
(http://freeemergencytalks.net/2010/04/gary-gaddis-rhabdomyolysis-and-compartment-syndrome/)
Discussion: …..Time for your thoughts!
Extra slides
BUN : Cr Ratio
http://en.wikipedia.org/wiki/BUN-to-creatinine_ratio
BUN: Cr ratio is low in Rhabdomyolysis
Mannitol & Loop diuretics??
Limited evidence for Diuretics preventing acute kidney injury Diuretics decreasing Mortality
Diuretics are useful if become fluid overloaded whilst being treated for Rhabdomyolysis
Gary Gaddis MD, Orthopaedist “Rhabdomyolysis & Compartment Syndrome
Talk at Orthopaedic Emergencies and Trauma (Cancun 2008) Pod cast from Joe Lex @ http://freeemergencytalks.net/
Huerta-Alardin A, Varon J, Marik P. Bench-to-bedside review: Rhabdomyolysis -- an overview for clinicians. Critical Care. 2005;9(15774072):158-169.