Stridor: Causes, Pathophysiology, and Management Strategies for Airway Obstruction
Discuss briefly stridor.
Or
Write briefly on stridor.
Answer. Stridor is an abnormal, high-pitched sound produced by turbulent airflow through a partially obstructed airway at the level of the supraglotts, glotts, subglotts, and/or trachea.
- Stridor is a symptom, not a diagnosis or disease, and the underlying cause must be determined.
- Stridor may be inspiratory, expiratory, or biphasic depending on its timing in the respiratory cycle.
- Inspiratory stridor suggests a laryngeal obstruction,while expiratory stridor implies tracheobronchial obstruction.
- Biphasic stridor suggests a subglottic or glottic anomaly.
- In addition to a complete history and physical,as well as other possible additional studies, most cases require flxible and/or rigid endoscopy to adequately evaluate the etiology of stridor.
“Symptoms Of Stridor In Children”
Stridor Pathophysiology
Gases produce pressure equally in all directions; however,when a gas moves in a linear direction, it produces pressure in the forward vector and decreases the lateral pressure.
When air passes through a narrowed flxible airway in a child, the lateral pressure that holds the airway open can drop precipitously (the Bernoulli principle) and cause the tube to close.
This process obstructs airflw and produces stridor.
Stridors may result from lesions involving the CNS, the cardiovascular system, the GI system, and the respiratory tract.
Stridor Etiology
Stridor may occur as a result of:
- Foreign bodies (e.g., aspirated foreign body, aspirated food bolus);
- Tumor (e.g., laryngeal papillomatosis, squamous cell carcinoma of larynx, trachea or esophagus)
- Acute lymphatic leukemia (ALL) (T-cell ALL can present with mediastinal mass that compresses the trachea and causes inspiratory stridor)
- Infections (e.g., epiglottitis, retropharyngeal abscess, croup)
- Subglottc stenosis (e.g., following prolonged intubation or congenital)
“Recovery Process After Stridor Treatment”
- Airway edema (e.g., following instrumentation of the airway, tracheal intubation, drug side effct, allergic reaction)
- Subglottc 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.
- Vasculitis.
“Treating Stridor Caused By Croup”
Stridor Treatment
Stridor Medical Care
- Immediate tracheal intubation should be done.
- Expectant management with full monitoring, oxygen by facemask, and positioning the head on the bed for optimum conditions (e.g., 45–90°).
- Use of nebulized racemic adrenaline 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.
- Use of dexamethasone (Decadron) 4–8 mg IV, 8 12 hourly 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.
“Dealing With Noisy Breathing Caused By Stridor”
- Use of inhaled Heliox (70% helium, 30% oxygen); the effct is almost instantaneous.
Helium, being a less dense gas than nitrogen, reduces turbulent flw through the airways.
Always ensure an open airway. - In obese patients elevation of the panniculus has shown to relieve symptoms by 80%.
“Preventing Complications From Untreated Stridor”
Stridor Surgical Care
- Certain conditions, such as severe laryngomalacia,laryngeal stenosis, critical tracheal stenosis, laryngeal and tracheal tumors and lesions (e.g., laryngeal papillomas, hemangiomas, others), and foreign body aspiration,require surgical correction.
- Occasionally, tracheotomy is done to protect the airway to bypass laryngeal abnormalities and stent or bypass tracheal abnormalities.
- Other conditions, such as retropharyngeal and peritonsillar abscess, may have to be dealt with on an emergent basis.
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