Kyphoscoliosis

Epidemiology


Etiology

Connective Tissue Disorder

Neuromuscular Disease

  • Cerebral Palsy
  • Friedrich’s Ataxia (see Friedrich’s Ataxia, [[Friedrichs Ataxia]])
  • Muscular Dystrophy (see Muscular Dystrophy, [[Muscular Dystrophy]])
    • Physiology: weakness of the paraspinal muscles resulting in abnormal development
  • Poliomyelitis (see Poliomyelitis, [[Poliomyelitis]])

Thoracic Cage Disorder

  • Post-Empyema
  • Post-Surgery for Recurrent Pneumothorax
  • Post-Thoracoplasty

Vertebral Disease

  • Neurofibromatosis (see Neurofibromatosis, [[Neurofibromatosis]])
  • Osteomalacia
  • Osteoporosis
  • Spondylitis
  • Tuberculosis (see xxxx, [[xxxx]])
  • Vitamin D-Resistant Rickets (see xxxx, [[xxxx]])

Idiopathic Kyphoscoliosis

  • Accounts for 80% of cases of kyphoscoliosis
  • Involves genetic factors and develops in early childhood

Physiology

Definitions

  • Kyphosis: curvature of spine in sagittal plane
    • May be isolated deformity (when associated with vertebral destruction)
  • Scoliosis: curvature of spine in coronal plane
    • Almost always involves some degree of kyphosis
  • Kyphoscoliosis: curvature of spine in both sagittal and coronal planes

Decreased

Pulmonary Hypertension

  • Pulmonary hypertension due to chest wall disease (hypoventilation due to decreased chest wall compliance: hypoxic pulmonary vasoconstriction and medial proliferation, compression of pulmon-ary arteries by low volumes)

  • Decreased chest wall compli-ance/lung compliance: increased elastic load (with increased work of breathing)

  • Ventilatory response to CO2: normal-slightly decreased (response is proportional to degree of mechanical limitation and lung volume restriction)

Diagnosis

Complete Blood Count (CBC) (see Complete Blood Count, [[Complete Blood Count]])

Arterial Blood Gas (ABG) (see Arterial Blood Gas, [[Arterial Blood Gas]])

  • Hypoxemia (see Hypoxemia, [[Hypoxemia]])
  • Normocapnia or Hypercapnia (see Chronic Hypoventilation, [[Chronic Hypoventilation]])
    • Hypercapnia occurs when VC is <30% of predicted (hypercapnia may also be related to patient age and inspiratory muscle weakness)

Pulmonary Function Tests (PFT’s) (see Pulmonary Function Tests, [[Pulmonary Function Tests]])

  • Restrictive Pattern: may be mild in adolescents with kyphoscoliosis
    • Normal FEV1/FVC (about 80% predicted)
    • Decreased VC (in adults: decreased in propor-tion to deformity/ uniformly decreased in patients with scoliosis >90 degrees): due to inspiratory muscle weakness, mechanical disadvantage of respiratory muscles
    • Decreased TLC (in adults: decreased in proportion to deformity/ uniformly decreased in patients with scoliosis >90 degrees): due to decreased lung compliance
    • Decreased FRC (due to decreased end-expira-tory position of chest wall due to decreased lung compliance)
    • Relatively preserved RV
    • Increased RV/ TLC ratio (as high as 50%)
    • Decreased lung compliance (due to decreased chest wall compliance and breathing at low lung volumes/ worsens with aging due to unknown structural changes): usually normal compliance in children, even with severe kyphoscoliosis
    • Decreased MIPS/MEPS: occurs independent of thoracic curvature/ probably due to mechanical disadvantage of muscles (MIP is typically about 50% of predicted in eucapnic cases, 25% of predicted in hypercapnic cases)
    • Decreased MVV (typically 40% of predicted)

Exercise Test (see xxxx, [[xxxx]])

  • Decreased VO2max: typically to 60-85% of normal
    • Due to deconditioning

Chest X-Ray (CXR) (see Chest X-Ray, [[Chest X-Ray]])

  • Reveals the deformity of spine (quantified by Cobb angle) and ribs

Chest CT (see Chest Computed Tomography, [[Chest Computed Tomography]])

  • Assesses deformity, lung parenchyma

Ventilation/Perfusion (V/Q) Scan (see Ventilation-Perfusion Scan, [[Ventilation-Perfusion Scan]])

  • Mismatch occurs when Cobb scoliosis angle is >65 degrees

Sleep Study (see Sleep Study, [[Sleep Study]])

  • xxx

Clinical Manifestations

Pulmonary manifestations

Dyspnea (see Dyspnea, [[Dyspnea]])

  • xxx

Rapid, Shallow Respiration (see Tachypnea, [[Tachypnea]])

  • Physiology:

Pulmonary Hypertension/Cor Pulmonale (see Pulmonary Hypertension, [[Pulmonary Hypertension]]): predicts death within one year without treatment

  • Physiology
    • Low Lung Volumes with Compression of Pulmonary Arteries
    • Decreased Chest Wall Compliance, Resulting in Hypoventilation
    • Hypoxic Pulmonary Vasoconstriction
    • Medial Proliferation
  • Clinical
    • xxx

Respiratory Muscle Fatigue

  • Physiology: respiratory muscle weakness and decreased lung compliance

Acute or Chronic Hypoventilation/Respiratory Failure (see Respiratory Failure, [[Respiratory Failure]])

  • Risk Factors for Respiratory Failure
    • Advanced Age of Onset
    • Cobb Angle >100 Degrees
    • Decreased Inspiratory Muscle Strength
    • Degree of Spinal Deformity
    • Presence of Paralysis: controversial
    • Sleep-Disordered Breathing

Nocturnal Hypoventilation

  • Physiology
    • Mechanism of NREM-Associated Hypoventilation: decreased respiratory drive during NREM
    • Mechanism of REM-Associated Hypoventilation: inhibition of intercostal and accessory muscles during RME
  • Clinical: worse during REM

Central Sleep Apnea (CSA) (see Central Sleep Apnea, [[Central Sleep Apnea]])

  • Physiology:

Obstructive Sleep Apnea (OSA) (see Obstructive Sleep Apnea, [[Obstructive Sleep Apnea]])

  • Physiology: due to distorted upper airway

Rheumatologic/Orthopedic Manifestations

  • Kyphosis: may be isolated deformity (when associated with vertebral destruction)
  • Scoliosis: almost always involves some degree of kyphosis

Treatment

General Measures

  • Chest Physical Therapy (CPT): as required
  • Oxygen (see Oxygen, [[Oxygen]]): improves survival in kyphoscoliosis (best results in patients <65 y/o and with pCO2 >55)
  • Prompt Treatment of Respiratory Infections
  • Treatment of Airway Obstruction: if present
    • Bronchodilators
  • Treatment of Concomitant Congestive Heart Failure (CHF) (see Congestive Heart Failure, [[Congestive Heart Failure]]): if present
  • Vaccination

Intermittent Positive Pressure Ventilation

  • Benefit lasts up to 3 hours after a 5 minute treatment (decreases atelectasis, etc.)

Treatment of Nocturnal Hypoventilation

Nocturnal Non-Invasive Positive Pressure Ventilation (NIPPV) (see Non-Invasive Positive Pressure Ventilation, [[Non-Invasive Positive Pressure Ventilation]])

  • General Comments
    • Systematic Review of Nocturnal NIPPV in Patients with Neuromuscular Disease and Chest Wall Disorders (2000) [MEDLINE]
      • Nocturnal ventilation improved short-term clinical symptoms and may prolong survival
      • However, comparison of efficacy between NIPPV vs mechanical ventilation could not be made from the available data
  • Average Volume Assured Pressure Support (VAPS) (see Volume Assured Pressure Support, [[Volume Assured Pressure Support]]) [MEDLINE]
    • Technique: set a target tidal volume, and the machine will maintain that tidal volume by varying the degree of pressure support delivered
    • Clinical Efficacy
      • VAPS may be more comfortable than bilevel ventilation (BiPAP) with a backup rate, as BiPAP provides a fixed amount of pressure support that is not affected by the patient’s effort

Tracheostomy with Nocturnal Mechanical Ventilation (see Tracheostomy, [[Tracheostomy]])

  • May Be Required in Severe Cases

Treatment of Obstructive Sleep Apnea (OSA) (see Obstructive Sleep Apnea, [[Obstructive Sleep Apnea]])

  • xxx

Surgical Intervention

  • High Surgical Complication Rates: >50% complication rate (in patients >20 y/o) with typically little clinical benefit

References

  • Nocturnal mechanical ventilation for chronic hypoventilation in patients with neuromuscular and chest wall disorders. Cochrane Database Syst Rev. 2000;(2):CD001941 [MEDLINE]
  • Therapy for sleep hypoventilation and central apnea syndromes. Curr Treat Options Neurol 2012;14(5):427-437 [MEDLINE]