croup. upper airway obstruction. swelling and irritation of vocal

respiratory croup cough windpipe throat acute larynx bronchitis laryngotracheobronchitis laryngitis inflammation viral voice mouth trachea influenza infection bacteria subglottic difficulty narrowing noisy syncytial bronchiolitis sound obstruction respiration pediatric breathing children symptom failure illnesses blocked syndrome asthma wheezing bronchial pneumonia swelling upper airway irritation vocal cord tube problem poor airflow lung