Download Slide 1

Chapter 29
Neuromuscular and Other Diseases
of the Chest Wall
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
Learning Objectives


List the potential respiratory complications
associated with neuromuscular disease.
Identify the clinical signs and symptoms
associated with respiratory muscle weakness.
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
2
Learning Objectives (cont.)


Describe techniques for monitoring the
patient with respiratory muscle weakness.
Describe the general respiratory care
management of patients with respiratory
muscle weakness.
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
3
Learning Objectives (cont.)

Describe the clinical findings and treatment for
each of the following neuromuscular disorders:
Duchennes muscular dystrophy, Myotonic
dystrophy, Polymyositis , Myasthenia gravis,
Lambert-Eaton syndrome, Guillain-Barre
syndrome, Unilateral diaphragmatic paralysis,
Amyotrophic lateral sclerosis, Critical illness
myopathy and polyneuropathy, Spinal cord
injury, Stroke, Traumatic brain injury,
Kyphoscoliosis, Flail chest
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
4
Introduction

Pulmonary consequences of NMD may
include:




Hyperventilation
Central apnea
Atelectasis leading to hypoxemia
Hypertension
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
5
Introduction (cont.)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
6
All of the following are consequences of
Neuromuscular disorder, except:
A.
B.
C.
D.
Atelactasis leading to hypoxemia
Hypertension
Central Apnea
Stroke
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
7
Principles of Neuromuscular
Weakness of Ventilatory Muscles



Pathophysiology & pulmonary function testing
Monitoring & assessing patients for
respiratory insufficiency
Management of respiratory muscle weakness
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
8
Pathophysiology & PFTs

NMD normal lung parenchyma reveals
restrictive defect



Normal or increased
RV & diffusing capacity
.
corrected for VA
Positional changes suggest diaphragmatic
weakness



Decreased VC, FEV1, TLC
Seated to supine: >20% decline in FEV1 & VC
Decreased PImax & Pemax
ABG: ⇓PaO2, ⇓PaCO2, but deterioration leads
to ⇑PaCO2
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
9
Pathophysiology & PFTs (cont.)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
10
All of the following reveal a restrictive lung defect,
except:
A.
B.
C.
D.
Increased RV
Decreased FVC
Decreased FEV1
Decreased TLC
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
11
Monitoring & Assessing Patients for
Respiratory Insufficiency

Respiratory muscle weakness leads to
fatigue & respiratory failure




May necessitate MV, so monitor carefully to
determine when to initiate
Monitoring involves serial measurements of
PImax, VC, & ABG values
May monitor maximal nasal sniff inspiratory
force & nocturnal oximetry
Close monitoring of all respiratory function is
important
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
12
Management of Respiratory
Muscle Weakness




Weakness leads to respiratory insufficiency &
retained secretions
Consider NIV or MV via tracheostomy
Augmentation of secretion clearance & assist with
cough
NIV increasingly used for short-term & intermittent
ventilatory support


i.e., Pneumonia or surgical event
Diaphragmatic pacing for spinal injuries FDA
approved

May be useful to treat NMD as well
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
13
Specific Neuromuscular Diseases

Disorders of muscle:



Duchenne Muscular Dystrophy
Myotinic Dystrophy
Polymyositis
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
14
Duchenne Muscular Dystrohpy



Genetic muscle-wasting disorder
Manifests early by waddling gait, lordosis,
frequent falls
Most affected children are wheelchair
dependent by age 12




Point of significant respiratory function decline
Adapt rapid shallow breathing pattern
Progression leads to PPV, initially only nocturnal
Death occurs by age 20, usually result of
declining respiratory muscle strength &
subsequent infection
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
15
Myotonic Dystrophy


Most common MD in adults
Respiratory dysfunction is common






Respiratory muscle weakness
OSA & CSA , very common even at early age
Bulbar muscle dysfunction
Aspiration
Tend to be sensitive to anesthesia & respiratory
depressants so prolonged postoperative
monitoring is required
Nocturnal NIV for oxygen & ventilation issues,
while central hypoventilation requires
tracheostomy & MV
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
16
Polymyositis


Inflammatory myopathy of unknown cause
Ventilatory insufficiency & failure are usual



If occurs, parallel progression of limb weakness
Corticosteroids are mainstay of initial
management
10–30% develop interstitial lung disease, with
diffuse infiltrates predominantly in bases
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
17
Disorders of the Neuromuscular
Junction


Myasthenia gravis (MG)
Lambert-Eaton syndrome (LES)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
18
Disorders of the Neuromuscular
Junction
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
19
Myasthenia Gravis

Characterized by intermittent muscle
weakness





Worsens with repetition
Improves with anticholinesterase medications
Caused by antibodies that inactivate ACh-R,
blocking electrical impulse transmission
Neoplastic growth within the thymus gland is
common
Typically occurs earlier in life in women &
later in men
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
20
Myasthenia Gravis (cont.)

Characterized by progressive loss of muscle
function often starting with eye muscles



Vary through day or progress, especially with
repetitive use
Diagnosis is by presence of anti–ACh-R
antibodies & improvement with use of
edrophonium
Treatment includes


Thymectomy & anticholinesterase drugs
Plasmapheresis to remove anti–ACh-R antibodies
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
21
Myasthenia Gravis (cont.)

Pulmonary complications depend on affected
muscles




Typically display


Upper airway obstruction
Exertional dyspnea
Ventilatory failure
Decreased TLC, VC, PImax, PEmax
• Sensitive markers of early respiratory muscle weakness
Myasthenic crisis is acute respiratory
insufficiency caused by infection, surgery or
excess anticholinesterase inhibitors
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
22
Myasthenia Gravis (cont.)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
23
Myasthenia Gravis (cont.)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
24
Lambert-Eaton Syndrome



More than fifty percent of cases associated with
cancer, most of those with small cell carcinoma of
lung
Autoantibodies interfere with release of ACh
Presence is supported by nerve conduction
studies


Increasing strength with repetition differentiates LES
from MG
Respiratory failure is rare
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
25
Disorders of the Nerves


Guillain-Barre Syndrome (GBS)
Phrenic Nerve & Diaphragmatic Paralysis
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
26
Disorders of the Nerves (cont.)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
27
Guillain-Barre Syndrome




Most common peripheral neuropathy
Characterized by paralysis & hyporeflexia, selflimiting
Thought to be caused by antimyelin antibodies
Diagnosis: High CSF protein levels & slow
impulse transmission
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
28
Patient has a sigh mechanism compromised with
Atelactasis ,mild hypoxemia and VC of 30 mL/kg.
Which would be most appropriate?
A.
B.
C.
D.
Chest physical therapy
Incentive Spirometry
Positive pressure ventilation
Full ventilation
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
29
Phrenic Nerve Damage &
Diaphragmatic Paralysis




Phrenic nerve arises from C3 to C5
Damage to one phrenic nerve affects one
hemidiaphragm
Bilateral interruption in high cervical injuries
results in complete diaphragmatic paralysis
Reversible unilateral paralysis can occur due
to pneumonia

Typically asymptomatic, diagnosed by radiography
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
30
Phrenic Nerve Damage &
Diaphragmatic Paralysis
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
31
Which of the following does the phrenic nerve
arise from?:
A.
B.
C.
D.
C1 to C3
C3 to C5
T1 to T3
T3 to T5
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
32
Disorders of the Spinal Cord


Amytrophic Lateral Sclerosis (ALS): Lou
Gehrig Disease
Spinal Cord Trauma
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
33
Amyotrophic Lateral Sclerosis (ALS):
Lou Gehrig Disease




Characterized by progressive deterioration of
upper & lower motor neurons
Male-to-female ratio for ALS is approximately
1.2:1
80% of patients have died by 5 years
Medical treatment is essentially ineffective

Riluzole: trials shown extended life 4.2 months
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
34
Amyotrophic Lateral Sclerosis (ALS):
Lou Gehrig Disease (cont.)

Supportive therapy central theme in
managing ALS



Key strategies: Prevent respiratory complications
& assess need for MV
If PEmax <40 cm H2O patient has ineffective
cough
• Treat with assisted cough, postural drainage
Consider instituting MV if:
• PImax <60 cm H2O, PaCO2 >45 mm Hg, VC <20 ml/kg,
or NSIF >–40 cm H2O
• Many patients opt not to prolong life with MV
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
35
All of the following would lead to initiation
mechanical ventilation in ALS patients, except:
A.
B.
C.
D.
VC >20 ml/kg
PaCO2 >45 mm Hg
PImax <60 cm H2O
NSIF >–40 cm H2O
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
36
Spinal Cord Trauma



Respiratory impact of spinal injury depends
on level of injury & if complete or partial
High cervical injuries (C1-2) result in
complete paralysis & death unless immediate
MV is instituted
Middle-low cervical injury (C3-C8): though
diaphragm is impacted at C3-C5, many can
come off MV

Adapt rapid shallow breathing pattern by use of
accessory muscles
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
37
Disorders of the Brain

Trauma, stroke, hemorrhage, & infection can
all impact respiration by:

Abnormalities in lungs themselves, such as
neurogenic pulmonary edema
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
38
Stroke




Interruption of blood flow to portion of brain,
which results in persistent dysfunction
Could be thrombotic, embolic or hemorrhagic
Impairment related to which structures were
damaged
Treatment



Early (3–4.5 hours) use of thrombolytic agents
after thrombotic event improves survival & function
Physical & occupational therapy
Speech therapy if indicated
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
39
Stroke (cont.)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
40
Traumatic Brain Injury

Blunt or penetrating injury resulting in brain
lesions


May cause direct trauma to respiratory centers
Cause neurogenic pulmonary edema,
hypersecretion of mucus, leading to respiratory
failure
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
41
Disorders of the Thoracic Cage


Kyphoscoliosis
Flail chest
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
42
Kyphoscoliosis


Posterior angulation of thorax (kyphosis) &
lateral curature of spine (scoliosis) occur
together
Kyphoscoliosis may result in hypoventilation,
hypercapnia, & pulmonary HTN


Decreased compliance seen with these patients
• Result in ⇓TLC & VC & restrictive disorder
• May have impaired diaphragmatic function
Spinal fixation may improve compliance, prevent
further pulmonary dysfunction, preexisting
conditions will not be reversed
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
43
Kyphoscoliosis (cont.)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
44
Kyphoscoliosis (cont.)
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
45
Flail Chest

Multiple rib fractures result in portion of chest
wall becoming free-floating, moving in
paradoxic motion during respiratory cycle


Bows out during expiration, in during inspiration
Often accompanied by pneumothorax,
pulmonary contusion, hemothorax, which
require emergent care
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
46