Stridor

Stridor

Stridor is a high pitched sound resulting from turbulent air flow in the upper airway. It is primarily inspiratory. 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.

A reduction in oxygen saturation is considered a late sign of airways obstruction, particularly in a child with healthy lungs and normal gas exchange.

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 adrenaline (0.5 to 0.75 ml of 2.25% racemic adrenaline added to 2.5 to 3 ml of normal saline) in cases where airway oedema 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 adrenaline [because of the risk of ventricular arrhythmias].)

• Use of dexamethasone (Decadron) 4-8 mg IV q 8 - 12 h in cases where airway oedema 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. Helium, being a less dense gas than nitrogen, reduces turbulent flow through the airways.

Causes

Stridor may occur as a result of:

• foreign bodies (e.g., aspirated peanut, aspirated food bolus),
• tumor (e.g., laryngeal papillomatosis, squamous cell carcinoma of larynx, trachea or esophagus),
• 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),
• laryngomalacia (the most common congenital cause of stridor); a video showing inspiratory stridor in a child with laryngomalacia can be seen at http://www.veomed.com/va073015232009.
• subglottic hemangioma (rare),
• vascular rings compressing the trachea
• Many thyroiditis such as Riedel's thyroiditis
• vocal cord palsy
• Tracheomalacia or Tracheobronchomalacia (e.g., collapsed trachea)
• Congenital anomalies of the airway are present in 87% of all cases of stridor in infants and children.
• Patients with enlarged oral and laryngeal anatomy have a close correlation to parents who tested positive for cannabis during pregnancy.

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, bronchoscopy, CT-scans, and / or MRIs may reveal structural pathology.

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

External links

• Stridor at eMedicine
• Congenital stridor at eMedicine
• MedlinePlus Encyclopedia: Breathing sounds - abnormal (stridor)
• Diseases Database (DDB): 27190
• Stridor sounds at R.A.L.E. Lung Sounds