This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
Recognised cause of stridor in newborn- 
Select and explain. 
A. Cystic hygroma, B. A Vascular ring, C. Laryngomalacia, D. All are true
D: All are true
Answer: D: All are true 
Explanation: Ans. is 'd' i.e., All of the above Stridor o Stridor refers to the physical finding of excessively noisy breathing and is general due to airway obstruction. Causes of Stridor in a child Infections Congenital Neoplasms o Croup (laryngotracheobronchitis) o Laryngomalacia o Subglottic hemangioma o Epiglotitis o Vocal cord palsy o Laryngeal papillomas o Bacterial tracheitis o Subglottic stenosis o Retropharyngeal abscess o Vascular ring o Saccular cyst o Cystic hygroma, when it occurs in larynx then it can cause respiratory tract obustruction