Epidemiology
- Incidence: 8 per 1000
Etiology
- Probably due to congenital defect of connective tissue surrounding sternum
- Associated with : Marfan’s syndrome
Physiology
- Pulmonary HTN due to chest wall disease (decreased chest volume with normal rib cage mobility)
- Hypoventilation leads to hypoxia/ acidosis (with resultant pulmonary vasoconstriction)
Diagnosis
- PFT’s (usually mild restriction):
-FEV1/FVC ratio: normal (about 80% of predicted)
-VC: normal-mildly decreased (usually about 90% of predicted)
-TLC: normal-mildly decreased (usually about 80% of predicted)
-Lung compliance: normal
-MVV: normal
Exercise test: controversial as to whether exercise is altered
Clinical
(symptoms occur in up to 30% of cases)
- Chest pain
- Exertional dyspnea
- Sunken anterior chest
- Pulmonary Hypertension/Cor Pulmonale (see [[Pulmonary Hypertension]])
- Chronic Hypoventilation (see Chronic Hypoventilation, [[Chronic Hypoventilation]])
Treatment
- Surgery: useful for patients with transthoracic distance: sternovertebral distance ratio >3.5
- May improve TLC/ MVV/ VO2max (controversial) but is cosmetically useful
- Younger patients may benefit more (due to normal growth following surgery) but this is unproven
References
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