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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