Neuromuscular Disorders in ICU Flashcards
What are the categories of neuromuscular disorders?
- Spinal level
- Neuromuscular junction
- Non-specific muscle contraction
- Peripheral neuropathy
What are examples of diseases that stem from the spinal anterior horn cells?
- Motor neurone disease
- Poliomyelitis
What is motor neurone disease (MND)?
- Group of diseases affecting motor neurons in brain & spinal cord
- Rapidly progressive, fatal, no cure
- Unknown cause
- Life expectancy approx 2-5 years from diagnosis
What are examples of neuromuscular junction pathologies?
- Myasthenia gravis
- Botulism (rare, related to bacteria)
What is myasthenia gravis?
- Chronic, autoimmune muscular disease
- Varying differences in muscle weakness
- Normal life expectancy
What is ICU acquired weakness?
- Muscle contraction pathology
- Critical illness is only cause of weakness
- Can be critical illness myopathy (CIM) or critical illness polyneuropathy (CIP)
What are the risk factors for ICUAW?
- Prolonged MV
- Severe systemic inflammation
- Corticosteroids & NM blocking agents
- Poor glycaemic control
- Immobility
What is a common peripheral nerve conduction disease?
Guillain Barre syndrome
What is Guillain Barre syndrome (GBS)?
- Demyelinating peripheral neuropathy
- Most common form of neuromuscular paralysis in developed countries
- Umbrella term for heterogenous group of immunologically mediated disorders of peripheral nerve function
What is the pathophysiology of GBS?
- Infiltration of mono-nuclear cells of endoneurium
- Inflammation along length of nerve
- Focused at nerve roots, spinal nerves & plexuses
- Macrophages actively strip myelin from Schwann cells & axons
What are some of the variations of GBS?
- 45% include cranial nerves
- 1/3 of cases require MV
- Sensory loss (vibration, proprioception, pain or hyperaesthesia)
- Autonomic dysfunction
What are some of the types of autonomic dysfunction that may occur in GBS?
- Orthostatic hypotension
- Hypotension
- Hypertension
- Bradycardia
- Ventricular tachyarrhythmias
- Paralytic ileus
- Urinary retention
- Abnormal sweating
- Bladder dysfunction & constipation are common
What are the required signs/symptoms for GBS diagnosis?
- Progressive weakness in both arms & legs (begins in lower extremities & ascends)
- Areflexia (loss of reflexes)
- Ataxia (loss of bodily movements)
- Minimal muscle atrophy
- May have problems with respiration, talking, swelling, bladder & bowel dysfunction
What are the risk factors for GBS?
- Possibly autoimmune
- Association with immunisations
- Frequently preceded by mild respiratory or intestinal infection
What are the supportive signs/symptoms for GBS diagnosis?
- Progression of symptoms over days to 4 weeks
- Symmetry of symptoms
- Mild sensory symptoms/signs
- Cranial nerve involvement
- Recovery beginning after 2-4 weeks
- Autonomic dysfunction
- No fever at onset
- High concentration of protein in CSF
- Electrodiagnostic features
What are some of the stats for GBS?
- 89% have pain
- 25% require MV
- 20% unable to walk unaided at 6 months
- Fatigue for years after
- DVT or PE risk 4-67 days after onset
- 20% have arrhythmias or hyper/hypotension
What can bulbar muscle function lead to in GBS?
- Difficulty in swallowing, airway protection & compromising gas exchange
What can occur within 7 days prior to admission in GBS?
- Inability to cough, stand or flex arms or head
- Raised liver enzymes
- VC <60% predicted
- Pimax = <30cmH2O
- Pemax = <40cmH2O
What ventilation do GBS patients require?
- Mean ventilation range 15-43 days
- Early trache increases comfort & airway safety vs permanent disfigurement, haemorrhage, infection etc
What is the role of physio in GBS?
- Chest treatment: Hyperinflation, manual techniques, positioning, cough assist machine (following weaning)
- Weaning ventilation
- Maintaining ROM & strength as able
- Early mobilisation
What does physio respiratory management in GBS include?
- Observation
- Palpation
- Auscultation
- Cough (measured objectively with peak flow meter)
- Vital capacity
- CXR
- ABGs
- WOB
- Respiratory rate, SpO2
- RPE/Borg scale
What are the key points of cough?
- Adequate expiratory flow required
- Normal peak expiratory flow in 6-12L/s
- Normal peak cough flows reaching 20 L/s
- May be reduced in patients with inspiratory/expiratory weakness (low lung volumes & difficulty clearing secretions)
How is vital capacity measured?
- Mechanical ventilator
- Spirometry
- Compare to normal values
What are the respiratory treatment goals in GBS?
- Volume restoration
- Secretion clearance
