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Upper Airway Obstruction BY AHMAD YOUNES PROFESSOR OF THORACIC MEDICINE Mansoura Faculty of Medicine. Upper Airway Obstruction.
BYAHMAD YOUNESPROFESSOR OF THORACIC MEDICINE
Mansoura Faculty of Medicine
Typically, significant anatomic obstruction precedes overt symptoms. For example, by the time exertional dyspnea occurs, the airway diameter is likely to be reduced to about 8 mm.
Dyspnea at rest develops when the airway diameter reaches 5 mm, coinciding with the onset of stridor.
Stridor is a loud ,musical sound of constant pitch that usually connotes obstruction of the larynx or upper trachea.
Sound recordings from the neck and chest have shown that the sound signals from the asthmatic wheeze and stridor are of similar frequency. This explains why errors in diagnosis can be made and an upper airway obstruction due to a tumor or foreign body may be mistakenly treated as asthma.
CT of the neck shows a laryngeal abscess with significant impingement on the laryngeal inlet. The flow-volume loop demonstrates a plateau of flow during inspiration and expiration, the FEF50%/FIF50% ratio is near 1.
Variable extrathoracic obstruction due to thyroid cyst. A. CT of the neck shows a 10- × 4-cm cystic mass (large arrow) in the thyroid gland compressing the trachea (small arrow).B . Flow-volume loop shows inspiratory obstruction.FEF50%/FIF50% is very high, and the inspiratory curve is flattened.
Variable intrathoracic obstruction due to squamous cell carcinoma of the trachea.A. CT of the chest shows a tracheal lesion (arrow). B . Superimposed flow volume loops show a plateau of expiratory flow preceded by a peak of flow at higher lung volumes. The forced inspiratory flow is preserved in comparison to expiratory flow, but it is also reduced. FEF50%/FIF50% is 0.4.
Acute epiglottitis.Lateral soft-tissue radiograph ofthe neck of a patient with stridor shows swelling of the epiglottis (large arrow) and loss of normal convexity of the edematous aryepiglottic folds (small arrow).
A. CT scan of the chestdemonstrating marked narrowing of the trachea with intraluminalcalcified nodular projections in a patient with tracheopathiaosteoplastica. B . CT scan of the chestdemonstrating multiplanner reformation of the trachea in thesagittal plane of the same patient.
HRCT of the chest with three-dimensional reconstruction of the upper airway showing focal tracheal compression (A, B )..
Deep Cervical Space Infections
Sarcoidosis may be associated with granulomatous infiltration and obstruction of the upper airways.
Pulmonary amyloidosisincludes tracheobronchial manifestations.
Tracheopathia osteoplasticais a rare, benign disease of the trachea and major bronchi in which cartilaginous or osseous nodules project into the airway lumen, often causing considerable airway deformity.
Inflammatory bowel disease produces tracheobronchial stenosis and severe airflow obstruction.
Laryngopharyngeal reflux may contribute to subglottic stenosis and, when documented, merits treatment.
Idiopathic progressive subglottic stenosis may be diagnosed in the absence of a clear, underlying etiology.
Mediastinal Masses and Lymphadenopathy
Pulmonary artery slingwith anomalous origin of the left pulmonary artery from the right pulmonary artery is very rare in adults.
Variable extrathoracic obstructiondue to vocal cord dysfunction.Two consecutive flow-volume loops from a young woman with inspiratory stridor.Variable effort accounts for the differences in configuration.FEF50%/FIF50% in each is very high.The inspiratory loop is flat and demonstrates a saw tooth pattern. This pattern has also beenassociated with sleep apnea syndrome and various neuromuscular disorders.