**Question:** Most common cause of stridor sholy after bih

**Core Concept:** Stridor is high-pitched inspiratory noise heard during breathing, typically in infants and young children, and can be indicative of a laryngeal or tracheal obstruction. Bih refers to the laryngeal inlet, which is the opening into the larynx where the vocal cords are located.

**Why the Correct Answer is Right:** The correct answer, "Bih (laryngeal)", refers to the most common cause of stridor after birth, which is a laryngeal obstruction. Laryngeal causes of stridor can be due to primary congenital or acquired conditions affecting the larynx. Examples include:

1. **Laryngomalacia:** A condition characterized by the flaccidity and collapse of the supraglottic soft tissues, leading to laryngeal obstruction during inspiration.
2. **Laryngeal cysts:** Benign or malignant masses can obstruct the laryngeal inlet, causing stridor.
3. **Laryngeal tumors (benign or malignant):** These can cause laryngeal obstruction due to their size, location, or growth pattern.
4. **Laryngeal deviation:** Structural abnormalities leading to a narrowing of the laryngeal inlet, such as a subglottic stenosis or a laryngeal cartilage malformation.
5. **Laryngotracheobronchitis (croup):** Inflammatory process involving the larynx, trachea, and bronchi, which can lead to stridor due to edema and narrowing of the airways.

**Why Each Wrong Option is Incorrect:**

A. **Vocal cord paralysis (VCP):** Vocal cord paralysis occurs when one or both vocal cords are unable to move properly, resulting in a fixed position and airway obstruction. However, this is generally acquired, not present at birth.

B. **Vocal cord polyps:** These are benign growths on the vocal cords, which usually cause hoarse voice and dysphonia (hoarseness), not stridor.

C. **Laryngeal edema:** While edema can cause stridor, it is not specific to the laryngeal inlet, as it can affect any part of the airway.

D. **Laryngeal tuberculosis:** Although tuberculosis can involve the larynx, the question specifically asks for the most common cause of stridor after birth. Tuberculosis is a rare cause of stridor, and the term "Bih" is unclear and confusing.

**Clinical Pearls:**

1. Stridor in neonates and infants is a significant symptom as it can indicate a critical airway obstruction, which requires immediate attention and intervention.
2. A thorough clinical examination and history are essential in differentiating between supraglottic and subglottic stridor, guiding the appropriate management of the child or patient.
3. Early recognition and management of stridor can prevent respiratory