Chronic Hypoventilation

Etiology: Disorders with Decreased Ventilatory Drive

Metabolic Alkalosis (see Metabolic Alkalosis)

  • Elevated serum bicarbonate -> increased serum pH -> physiologic decrease in central respiratory drive

Chemosensitivity Disorders

  • Carotid Body Dysfunction (see Carotid Body Dysfunction, [[Carotid Body Dysfunction]]): may play a role in sudden infant death syndrome (SIDS)
  • Carotid Body Trauma: due to carotid endarterectomy, etc
  • Central Sleep Apnea (see Central Sleep Apnea, [[Central Sleep Apnea]])
  • Chronic Mountain Sickness (see Chronic Mountain Sickness, [[Chronic Mountain Sickness]]): chronic hypoxia
  • Hypothyroidism (see Hypothyroidism, [[Hypothyroidism]]): hypothyroidism-associated chronic hypoventilation is due to a combination of decreased central respiratory drive, neuropathy, and myopathy

Brainstem Disease

(Note: Ambien does not produce significant respiratory depression)


Etiology: Disorders with Decreased Ventilatory Output (Despite Increased Ventilatory Effort)

Spinal Cord Disease

High Cervical (Above C3) or Low-Mid Cervical (C3-C8) Spinal Cord Disease (see Cervical Spinal Cord Disease, [[Cervical Spinal Cord Disease]])

  • Atlanto-Axial Subluxation: associated with rheumatoid arthritis
  • Cervical Disk Disease with Cord Compression
  • Cervical Osteoarthritis
  • Cervical Space-Occupying Lesions
    • Cervical Echinococcal Cyst
    • Cervical Epidural Abscess
    • Cervical Gumma
    • Cervical Hematoma
    • Cervical Tumor
  • Cervical Spinal Cord Infarction (see Spinal Cord Infarction, [[Spinal Cord Infarction]])
  • Cervical Spine Trauma with Cord Injury
  • Diastematomyelia: bony spur in spinal canal, which may compress cervical spinal cord
  • Post-Cervical Cordotomy: procedure done to achieve pain control may damage ascending and descending tracts
  • Spondylolisthesis/Cervical Spondylosis
  • Syringomelia: cavitation of central cord
  • Thoracic Outlet Syndrome (see Thoracic Outlet Syndrome, [[Thoracic Outlet Syndrome]])
  • Transverse Myelitis (see Transverse Myelitis, [[Transverse Myelitis]])

Cervical Root Disease (see Cervical Root Disease, [[Cervical Root Disease]])

  • Cervical Osteoarthritis (with bilateral C3-C5 compression)
  • Cervical Spine Manipulation/Mass Lesion (with bilateral C3-C5 compression)
  • Herpes Zoster (bilaterally involving C3-C5)
  • Multiple Sclerosis (bilaterally involving C3-C5)
  • Neuralgic Amyotrophy (bilaterally involving C3-C5): usually affects brachial plexus

Motor Neuron Disease

  • Amyotrophic Lateral Sclerosis (ALS) (see Amyotrophic Lateral Sclerosis, [[Amyotrophic Lateral Sclerosis]])
    • Upper and lower motor neuron disease
    • Acute ventilatory failure may be the initial presentation of ALS
  • Kennedy Disease: lower motor neuron disease due to androgen receptor mutation (X-linked) with age of onset from adolescence-old age in males
  • Poliomyelitis (see Poliomyelitis, [[Poliomyelitis]])
  • Post-Polio Syndrome (see Poliomyelitis, [[Poliomyelitis]])
  • Primary Lateral Sclerosis: upper motor neuron disease
  • Progressive Muscular Atrophy (PMA): lower motor neuron disease
  • Spinal Muscular Atrophies: lower motor neuron disease
  • Strychnine Intoxication (see Strychnine, [[Strychnine]])
  • Survival of Motor Neuron (SMN) Protein-Associated Spinal Muscular Atrophy (all involve gene defect of the Survival of Motor Neuron protein)
    • Werdnig-Hoffman Disease (Type 1): lower motor neuron disease with onset at 0-6 mo
    • Type 2 Survival of Motor Neuron Protein-Associated Spinal Muscular Atrophy: lower motor neuron disease with onset at 7-18 mo
    • Kugelberg-Welander Disease (Type 3): lower motor neuron disease with onset at >18 mo
    • Adult-Onset (Type 4) Survival of Motor Neuron Protein-Associated Spinal Muscular Atrophy: lower motor neuron disease with adult onset
  • Tetanus (see Tetanus, [[Tetanus]])
    • Mechanism: damaged upper motor neurons can no longer inhibit lower motor neurons

Peripheral Neuropathy (see Phrenic Neuropathy, [[Phrenic Neuropathy]])

Infection/Toxin

Other

  • Acute Intermittent Porphyria (see Acute Intermittent Porphyria, [[Acute Intermittent Porphyria]])
  • Chronic Inflammatory Demyelinating Polyneuropathy (see Chronic Inflammatory Demyelinating Polyneuropathy, [[Chronic Inflammatory Demyelinating Polyneuropathy]])
  • Critical Illness Polyneuropathy (see ICU-Acquired Weakness, [[ICU-Acquired Weakness]])
  • Diabetic Neuropathy (see Diabetic Neuropathy, [[Diabetic Neuropathy]])
  • Guillain-Barre Syndrome (see Guillain-Barre Syndrome, [[Guillain-Barre Syndrome]]): most common etiology of acute paralysis and neuromuscular ventlatory failure presenting to acute care hospitals
    • 33% of cases develop acute ventilatory failure
    • May be acute or subacute
    • Ascending paralysis (similar to tick paralysis and in contrast to descending paralysis seen in botulism and paralytic-neurotoxic shellfish poisoning)
  • Hypothyroidism (see Hypothyroidism, [[Hypothyroidism]]): hypothyroidism-associated chronic hypoventilation is due to a combination of decreased central respiratory drive, phrenic neuropathy, and respiratory muscle myopathy
  • Idiopathic Peripheral Neuropathy
  • Mediastinal/Esophageal Surgical Injury or Traumatic Injury of Bilateral Phrenic Nerves
    • Phrenic nerve injury occurs in 2-20% of open heart surgery cases
    • L>R sided injury
    • Mechanisms: cold cardioplegia, dissection of LIMA, and/or stretching of phrenic nerve
  • Multiple Sclerosis (see Multiple Sclerosis, [[Multiple Sclerosis]])
  • Neurofibromatosis (see Neurofibromatosis, [[Neurofibromatosis]]): case report of bilateral diaphragmatic paralysis
  • Systemic Lupus Erythematosus (SLE) (see Systemic Lupus Erythematosus, [[Systemic Lupus Erythematosus]]): neuropathy with vasculitis of phrenic nerves + myopathy

Neuromuscular Junction Disease (Involving Respiratory Muscles)

  • Myasthenia Gravis (see Myasthenia Gravis, [[Myasthenia Gravis]]): acute ventilatory failure may be the initial presentation of myasthenia gravis
  • Lambert-Eaton Myasthenic Syndrome (LEMS) (see Lambert-Eaton Myasthenic Syndrome, [[Lambert-Eaton Myasthenic Syndrome]])
  • Botulism (see Botulism, [[Botulism]])
    • Mechanism: botulinum toxin blocks acetylcholine release at neuromuscular junction
    • Descending paralysis (similar to paralytic-neurotoxic shellfish poisoning and in contrast to ascending paralysis seen in GBS and tick paralysis)
  • Tick Paralysis (see Tick Paralysis, [[Tick Paralysis]])
    • Mechanism: toxin probably impairs acetylcholine mobilization at motor nerve terminal
    • Ascending paralysis (similar to GBS and in contrast to descending paralysis seen in paralytic-neurotoxic shellfish poisoning and botulism)
  • Organophosphate Intoxication (see Organophosphates, [[Organophosphates]]) [MEDLINE]
  • Carbamate Intoxication (see Carbamates, [[Carbamates]]) [MEDLINE]
  • VX Nerve Agent (see VX Nerve Agent, [[VX Nerve Agent]])
  • Pharmacologic Neuromuscular Junction Antagonists
    • Aminoglycosides (see Aminoglycosides, [[Aminoglycosides]]): usually clinically relevant only in the presence of other NM disease
    • Fluoroquinolones (see Fluoroquinolones, [[Fluoroquinolones]]): usually clinically relevant only in the presence of other neuromuscular disease
    • Anti-Cholinergics: usually clinically relevant only in the presence of other neuromuscular disease
    • Procainamide (see Procainamide, [[Procainamide]]): usually clinically relevant only in the presence of other neuromuscular disease
    • Polymyxin B (see Polymyxins, [[Polymyxins]]): usually clinically relevant only in the presence of other neuromuscular disease
    • Sodium Colistimethate (aka Colistin, Polymyxin E) (see Polymyxins, [[Polymyxins]]): usually clinically relevant only in the presence of other neuromuscular disease

Myopathy (Involving Respiratory Muscles)/Muscle Dysfunction (see Myopathy, [[Myopathy]])

Periodic Paralysis Syndromes

Rheumatologic

Electrolyte-Related

Other

  • Bilateral Diaphragmatic Paralysis (see Bilateral Diaphragmatic Paralysis, [[Bilateral Diaphragmatic Paralysis]])
  • Critical Illness Polymyopathy (see ICU-Acquired Weakness, [[ICU-Acquired Weakness]])
    • Necrotizing Myopathy from Steroids + NMJ Blockers:
  • Hyperthyroidism (see Hyperthyroidism, [[Hyperthyroidism]])
    • Proximal and distal myopathy -> manifests as both inspiratory and expiratory weakness
  • Hypothyroidism (see Hypothyroidism, [[Hypothyroidism]]): hypothyroidism-associated chronic hypoventilation is due to a combination of decreased central respiratory drive, neuropathy, and myopathy
    • Manifests as both inspiratory and expiratory weakness

Progressive Upper Airway Obstruction (with Increased Work of Breathing) (see Obstructive Lung Disease, [[Obstructive Lung Disease]])

  • Infection
  • Neoplasm
    • Cervical Node Metastases: extrinsic compression of upper airway
      • Thyroid Cancer (see Thyroid Cancer, [[Thyroid Cancer]])
      • Head and Neck Cancer
    • Histiocytoma
    • Laryngeal Carcinoma
    • Laryngeal Papilloma
    • Laryngeal Cartilaginous Tumor
    • Laryngeal Angioma
    • Laryngeal Cystic Hygroma
    • Lymphoma Involving Upper Airway (see Lymphoma, [[Lymphoma]])
    • Thyroid Cancer (see Thyroid Cancer, [[Thyroid Cancer]])
    • Tracheal Adenoid Cystic Carcinoma (see Adenoid Cystic Carcinoma, [[Adenoid Cystic Carcinoma]])
  • Neurologic
  • Other
    • Bilateral Vocal Fold Immobility (see Bilateral Vocal Fold Immobility, [[Bilateral Vocal Fold Immobility]])
    • Congenital Small Cricoid Cartilage
    • Esophageal Foreign Body: extrinsic compression of upper airway
    • Laryngeal Congenital Malformation
    • Laryngeal Granuloma
    • Laryngeal Polyp
    • Relapsing Polychondritis (see Relapsing Polychondritis, [[Relapsing Polychondritis]])
    • Thyromegaly/Goiter (see Goiter, [[Goiter]])
    • Tracheal Cyst
    • Tracheomalacia (see Tracheomalacia, [[Tracheomalacia]])
    • Tonsillar/Adenoid Enlargement

Obstructive Airway Disease (with Increased Work of Breathing) (see Obstructive Lung Disease, [[Obstructive Lung Disease]])


Acute Parenchymal Lung Disease (with Increased Work of Breathing)

  • Chronic Obstructive Pulmonary Disease (COPD) (see Chronic Obstructive Pulmonary Disease, [[Chronic Obstructive Pulmonary Disease]]): most common cause of chronic hypoventilation
  • Idiopathic Pulmonary Fibrosis (IPF) (see Idiopathic Pulmonary Fibrosis, [[Idiopathic Pulmonary Fibrosis]]: acute ventilatory failure may be manifested as the end-stage of the IPF or more commonly, in conjunction with pneumonia, surgery, or other illness
    • In end-stage IPF requiring mechanical ventilation, lung compliance has been noted to be significantly decreased

Pleural or Chest Wall Disease (with Increased Work of Breathing)


Diagnosis of Chronic Hypoventilation

  • Chemosensitivity Disorders
    • ABG: normal A-a gradient
    • PFT’s: normal spirometry and lung volumes (usually), normal MIP+MEP
  • Neuromuscular Disease
    • ABG: normal A-a gradient
    • PFT’s: restriction, decreased MIP+MEP
  • Upper Airway/Lower Airway/Chest Wall Disease
    • ABG: increased A-a gradient
    • PFT’s: restriction or obstruction, normal MIP+MEP

Clinical Features of Chronic Hypoventilation

  • Consequences of Hypoventilation-Associated Sleep-Disordered Breathing
    • Morning Headache: due to cerebral vasodilation
    • Sleep Disruption: due to cerebral vasodilation
    • Daytime Somnolence: due to cerebral vasodilation
    • Confusion: due to cerebral vasodilation
    • Pulmonary Hypertension/Cor Pulmonale (see Pulmonary Hypertension, [[Pulmonary Hypertension]])
  • Consequences of Hypoventilation-Associated Hypercapnia
    • Metabolic Compensation: elevated bicarbonate
  • Consequences of Hypoventilation-Associated Hypoxemia
    • Cyanosis
    • Polycythemia
    • Pulmonary Hypertension/Cor Pulmonale (see Pulmonary Hypertension, [[Pulmonary Hypertension]])

Treatment

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References

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