Stridor

Stridor
Inspiratory and expiratory stridor in a 13-month child withcroup
Specialty	Otorhinolaryngology,pediatrics

Stridor(fromLatin'creaking/grating noise') is an extra-thoracichigh-pitchedbreath soundresulting fromturbulentair flow in thelarynxor lower in thebronchial tree.It is different from astertor,which is a noise originating in thepharynx.

Stridor is a physical sign which is caused by a narrowed orobstructed airway.It can beinspiratory,expiratoryorbiphasic,although it is usually heard during inspiration. Inspiratory stridor often occurs in children withcroup.It may be indicative of serious airway obstruction from severe conditions such asepiglottitis,a foreign body lodged in the airway, or a laryngeal tumor. Stridor should always command attention to establish its cause. Visualization of the airway by medical experts equipped to control the airway may be needed.

Causes

Stridor may occur as a result of:

• foreign bodies (e.g.,aspiratedforeign body,aspirated food bolus);
• infections (e.g.,epiglottitis,retropharyngeal abscess,croup);
• subglotticstenosis(e.g., following prolonged intubation or congenital);
• airway edema (e.g., following instrumentation of the airway,tracheal intubation,drug side effect,allergic reaction);
• laryngospasm(from aspiration,GERD,or complication ofanesthesia)
• subglottichemangioma(rare);
• vascular ringscompressing the trachea;
• thyroiditis such asRiedel's thyroiditis;
• vocal cordpalsy;
• tracheomalaciaor tracheobronchomalacia (e.g., collapsed trachea).
• congenitalanomalies of the airway are present in 87% of all cases of stridor in infants and children.
• vasculitis.
• infectious mononucleosis
• peritonsillar abscess
• Laryngeal edema is a common cause of stridor post extubation (occurring from pressure of the endotracheal tube on the mucosa as a result of endotracheal tube that is too large (e.g. pediatrics), cuff over inflation, and prolonged intubation times.);
• tumor (e.g., laryngeal papillomatosis,squamous cell carcinomaof larynx, trachea or esophagus);
• ALL(T-cell ALL can present with mediastinal mass that compresses the trachea and causes inspiratory stridor)

Diagnosis

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

Chest and neckx-rays,bronchoscopy,CT-scans,and/orMRIsmay reveal structural pathology.

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

Treatments

The first issue of clinical concern in the setting of stridor is whether or nottracheal intubationortracheostomyis immediately necessary. A reduction in oxygen saturation is considered a late sign of airway obstruction, particularly in a child with healthy lungs and normal gas exchange. 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 on the bed for optimum conditions (e.g., 45 - 90 degrees).
• Use ofnebulizedracemic adrenalineepinephrine(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. (NebulizedCodeinein 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 ofdexamethasone(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 needed for dexamethasone to work fully.
• Use of inhaledHeliox(70%helium,30%oxygen); the effect is almost instantaneous. Helium, being a less dense gas than nitrogen, reduces turbulent flow through the airways. Always ensure an open airway.

In obese patients elevation of thepanniculushas shown to relieve symptoms by 80%.

External links

• Audio Breath SoundsArchived2020-12-15 at theWayback Machine—Multiple case studies with audio files of lung sounds.
• StridorateMedicine
• Congenital stridorateMedicine
• MedlinePlus Encyclopedia:Breathing sounds—abnormal (stridor)
• Diseases Database(DDB):27190
• Stridor sounds at R.A.L.E. Lung Sounds