Stridor

Overview
Stridor is a high pitched sound resulting from turbulent gas flow in the upper airway. It may be inspiratory, expiratory or present on both inspiration and expiration. It can be indicative of serious airway obstruction from severe conditions such as epiglottitis, a foreign body lodged in the airway, or a laryngeal tumor. Stridor is indicative of a potential medical emergency and should always command attention. Wherever possible, attempts should be made to immediately establish the cause of the stridor (e.g., foreign body, vocal cord edema, tracheal compression by tumor, functional laryngeal dyskinesia, etc.) That examination requires visualization of the airway by a team of medical experts equipped to control the airway.

Common causes
Stridor has many different potential causes. It may occur as a result of:
 * foreign bodies (e.g., aspirated peanut, aspirated wire),
 * tumor formation (e.g., laryngeal papillomatosis, squamous cell carcinoma),
 * infections (e.g., epiglottitis, retropharyngeal abscess, croup),
 * subglottic stenosis (e.g., following prolonged intubation or congenital),
 * airway edema (e.g., following instrumentation of the airway intubation, drug side effect, allergic reaction),
 * as well as a result of laryngomalacia (the most common congenital cause of stridor),
 * subglottic hemangioma (rare),
 * and vascular rings compressing the trachea.
 * Abnormalities of vocal cord function can also be responsible.
 * Congenital anomalies of the airway are present in 87% of all cases of stridor in infants and children.

Inspiratory stridor

 * Allergy
 * Anaphylaxis
 * Angioneurotic edema
 * Aortic aneurysm
 * Aspiration
 * Bacterial tracheitis
 * Choanal atresia
 * Diptheria
 * Enlarged tonsils/adnoids
 * Epiglottitis
 * Facial fracture
 * Foreign body aspiration
 * Goiter
 * Hemangioma
 * Inhalation injury
 * Laryngeal or tracheal abnormalities
 * Laryngomalacia
 * Larynx Carcinoma
 * Laryngo-tracheal bronchitis
 * Laryngeal fracture
 * Maxillo-facial dysplasis
 * Mandibular fracture
 * Medastinal tumor
 * Nasal polyp
 * Nasal septum deviation
 * Neck or facial swelling
 * Nerve paresis
 * Neck surgery
 * Prolonged intubation
 * Post-radiation
 * Psychogenic
 * Retropharyngeal abscess
 * Scar stenosis
 * Secretions
 * Spasmodic croup
 * Subglottic stenosis
 * Tonsillitis
 * Trauma
 * Vocal cord cancer
 * Vocal cord paralysis

Expiratory stridor

 * Bronchitis
 * Bronchial asthma
 * Cardiac Failure
 * Compression of the bronchii due to lymph node enlargement
 * COPD
 * Foreign body aspiration
 * Pleura process
 * Pneumonia
 * Pneumothorax
 * Trachiobronchitis
 * Tumor infiltration

Treatments
The first issue of clinical concern in the setting of stridor is whether or not tracheal intubation or tracheostomy is immediately necessary. Some patients will need immediate tracheal intubation. If intubation can be delayed for a period a number of other potential options can be considered, depending on the severity of the situation and other clinical details. These include:


 * Expectant management with full monitoring, oxygen by face mask, and positioning the head of the bed for optimum conditions (e.g., 45 - 90 degrees)


 * Use of nebulized racemic epinephrine (0.5 to 0.75 ml of 2.25% racemic epinephrine added to 2.5 to 3 ml of normal saline) in cases where airway edema may be the cause of the stridor. ( Nebulized Cocaine in a dose not exceeding 3 mg/kg may also be used, but not together with racemic epinephrine [because of the risk of ventricular arrhythmias].)


 * Use of dexamethasone (Decadron) 4-8 mg IV q 8 - 12 h in cases where airway edema may be the cause of the stridor; note that some time (in the range of hours) may be need for dexamethasone to work fully.


 * Use of inhaled Heliox (70% helium, 30% oxygen); the effect is almost instantaneous

Diagnosis
Stridor is usually diagnosed the basis of history and physical examination, with a view to revealing the underlying problem or condition.

Chest and neck x-rays, CT-scans, and / or MRIs may reveal structural pathology.

Flexible fiberoptic bronchoscopy can also be very helpful, especially in assessing vocal cord function of in looking for signs of compression or infection.