Viva - ICU-AW Flashcards
Definition of ICU-AW
Detectable weakness in critically patients for which no plausible aeotiology is found, other than being critically ill.
How it is divdided
Myopathy (CIM)
Neuropathy/Polyneuropathy (CIPN)
Both (Critical Illness Neuromyopathy, CINM)
Clinically they are indistinguishable
Risk factors
Aetiology is uncertain but risks:
Immobility Severe sepsis MOF Excessive use of sedation Corticosteroids Uncontrolled sugars Neuromuscular blockade
More common in women, neurological disease and the elderly. Also parenteral nutrition
Features of the weakness
Flaccid
Symmetrical
All for limbs
Sparing of the face
How is it graded
MRC Score, graded from 0-5
Three muscles in upper and lower limbs and left/right give a total of 60.
Less < 48 suggests polyneuropathy
How is the MRC scored
0-5
5 Normal 4 Moves against resitsance 3 Moves against gravity 2 Movement with gravity eliminated 1 Flicker/Contraction 0 Nothing
Muscles assessed in MRC
Arm abduction Elbow flexion Wrist extension Hip flexion Knee Extension Foot dorsiflexion
Differentials of ICU-AW
Guillain Barre Myasthenia Lambert Eaton Spinal cord injry Rhabdo Drug induced weakness Myositis Infective - botulism Eletrolyte disturbance
How to investigate
Clinically MRC
Bloods - signs of infection, inflammatory markers
Renal, CK (mild elevation)
Electrolytes - rule out other causes, calcium etc
ESR
Auto antibodies
B12
MRI brainstem and spin
Nerve conduction, EMG, biopsy
What will nerve conduction show
CIM - normal
CIPN - decreased Compound Muscle Action Potential and sensory action potential. Conduction veloctiy normal
What woud EMG show
Needs a co-operative patient….
Small amplitude motor unit potential with short durations
Why would you do a biopsy
Diagnositc uncertainty
Exclude other diagnosis - demyelination
If it is CIM, this can be subclassified:
1) unspecific/uncomplicated
2) thick filament myopathy (loss of myosin with proteolyis)
3) Acute necrotising myopathy
Management
MDT
Prevention
Avoid risk factors
Early mobilisation and physio
Agressive sedation weaning protocol
Optimise nutrition and electrolytes
Stricy sugar control is an option but goes against the NICE-SUGAR trial
Electrical stimulation - can prevent (results vary)
Abdominal electrical stim prevents rectus abdominins and intercostal degradation
Limb, rebuilds after the event
FES - does not work
FES with cyling probably does not work
Cycling - does not work
Inspiratroy muscle training strenghtens the diaphgram but no mortality/weaning benefit demonstrated.
