Article by Dr Manasa S, B.A.M.S
Stridor, characterized by its abnormal, high-pitched respiratory sound, serves as a vital indicator of compromised airflow within a narrowed airway. Often pronounced during the inhalation phase, this condition signals a notable obstruction in the upper respiratory tract. Understanding the root cause of stridor is paramount for effective symptom management. Factors such as medical history, age, and symptom severity, particularly in children, play pivotal roles in discerning the underlying condition precipitating this respiratory anomaly.
Causes of stridor
Stridor is caused due to underlying pathology and may result from acute or chronic factors.
Acute stridor
Acute stridor typically starts within minutes to hours, they can also develop over days.
Acute causes include conditions such as croup, bacterial tracheitis, epiglottis, retropharyngeal abscess, foreign body aspiration, peritonsillar abscess, airway burns, anaphylaxis, therapeutic hypothermia, and post-extubation complications.
Patients with acute stridor are at a risk of experiencing rapid progression of the symptoms.
Chronic stridor
It is caused by a congenital or acquired abnormality.
It may persist for weeks
Generally, it becomes apparent within few weeks of life, some cases may manifest later in childhood
Causes of chronic stridor include conditions such as laryngomalacia, laryngeal webs, laryngeal cysts. Laryngeal clefts, subglottic stenosis, vocal cord paralysis, tracheomalacia, vascular ring, tracheal stenosis, and hypocalcemic spasm.
Common causes of stridor
– Laryngitis or swelling and irritation of the voice box
– Inhaling smoke
– Overproduction of phlegm
– Swollen tonsils
– Inhaling a foreign object
– An allergic reaction
– An injury to the airways
– Bronchoscopies and laryngoscopies
– Swelling of the face or neck
– Long term use of a breathing tube
– Cancer of the vocal cords
– Neck surgery
Symptoms associated with stridor
Hive – The presence of hives should prompt an immediate evaluation for anaphylaxis, which may be attributed to an allergic trigger.
Cough – Characteristic of croup, a barking cough signifies a potential respiratory issue requiring attention.
Drooling – Drooling, when observed alongside a muffled voice, suggests a likely supraglottic obstruction, such as a retropharyngeal abscess or epiglottitis. Conversely, drooling combined with dysphagia may indicate potential complications such as foreign body aspiration or external abnormalities compressing the oesophagus.
Mental Status – An altered mental state, particularly when accompanied by increased work of breathing, should serve as a significant indicator of a potential impending loss of airway.
Stridor During Feeding – The occurrence of stridor during feeding necessitates consideration of various underlying issues including tracheoesophageal fistula, gastroesophageal reflux, or swallowing dysfunction.
Fever – Fever, commonly associated with croup, epiglottitis, bacterial tracheitis, and retropharyngeal abscess, requires careful evaluation. Children displaying signs of toxicity coupled with a high fever are at an increased likelihood of bacterial infection, necessitating prompt medical attention.
Types of stridor
The classification of stridor is contingent upon its aetiology and anatomical location within the body. These classifications comprise:
1. Inspiratory stridor, characterized by the occurrence of sound during inhalation. This manifestation often arises from lax tissue surrounding the vocal cords, particularly prevalent in paediatric cases.
2. Expiratory stridor, distinguished by the presence of sound during exhalation. This presentation typically indicates an underlying issue located further down the respiratory tract.
3. Biphasic stridor, wherein the sound is evident during both inhalation and exhalation. This condition may stem from abnormalities in the cartilaginous structures situated beneath the vocal cords
Stridor in children
Stridor is most commonly seen in children than adults as children have narrower airways and that makes children more susceptible to blockages. Stridor can be congenital as well. In case of congenital abnormalities, the stridor and other related symptoms appear within a few weeks or months of the child birth.
Causes of stridor in adults
– Allergies
– Inhaling food or an object
– Surgery to your thyroid, chest, or oesophagus
– A breathing tube (intubation)
– Subglottic or tracheal stenosis
– Epiglottitis
– Tests like bronchoscopy or laryngoscopy
– Airway injury
– Vocal cord problems like an injury or paralysis
– Growths such as tumours
– Laryngitis
– Tonsillitis
– Smoke inhalation
– An abscess
Causes of Stridor in Children
Croup
Inflammation of vocal cords and windpipe, usually viral.
Most common in children between 6 months and 6 years, and more prevalent in males.
Symptoms – barking cough, hoarse voice, breathing difficulties.
At-home treatment would be sufficient in many cases. One should seek medical attention for breathing
difficulties.
Inhaled Object
Accidental inhalation of foreign objects.
Symptoms – stridor, difficulty breathing, wheezing, difficulty swallowing.
May require X-ray or other tests for confirmation.
Surgical removal for large, sharp, or dangerous objects.
Laryngomalacia
Softening of vocal cord tissues, leading to airway obstruction.
Typically present from birth; most children outgrow it.
Symptoms: inspiratory stridor, difficulty feeding, acid reflux.
Often improves without treatment by 18-20 months.
Vocal Cord Paralysis
Lack of movement in one or both vocal cords due to nerve injury or infection.
Symptoms: inspiratory stridor, weak voice, coughing or choking while feeding.
Surgical intervention may be necessary for unilateral paralysis lasting 1-2 years.
Subglottic Stenosis
Narrowing of airways within the voice box, usually due to scarring.
Symptoms: stridor, breathing difficulties, recurring croup.
Mild cases may improve without treatment; severe cases may require surgery.
Subglottic Haemangioma
Benign tumour of capillaries in the airway.
Symptoms: biphasic stridor, difficulty breathing, barking cough.
Rapid growth in infancy, followed by shrinkage.
Treatment may include propranolol, steroids, surgery, or a temporary breathing tube.
Vocal Cord Lesions
Nodules or papilloma affecting vocal cord function.
Symptoms: stridor, changes to voice, difficulty breathing, difficulty in eating, difficulty in exercising and acid reflux.
Surgery may be necessary for papilloma; nodules may require monitoring and reflux management.
Vascular Rings
Congenital abnormality where blood vessel rings encircle the windpipe.
Symptoms: noisy breathing, difficulty in eating and swallowing, choking, persistent cough and a feeling of something stuck in the throat.
Diagnosis is done with the help of MRI
Surgery may be needed to relieve pressure on the windpipe.
Bacterial Tracheitis
Rare, life-threatening bacterial infection of the windpipe.
Symptoms: biphasic stridor, septic shock.
Treatment involves intravenous antibiotics, breathing tubes, and ICU care.
Epiglottitis
Bacterial infection causing epiglottis inflammation.
Symptoms: stridor, fever, difficulty breathing, difficulty in swallowing, hoarse voice, drooling and bluish skin colour.
Requires oxygen, breathing tube, and hospitalization in most cases.
Diagnosis
The first step is the physical examination which is followed by detailed medical history.
Chest X- ray
CT scan of the chest
Laryngoscopy, which helps to see the voice box
Pulse oximetry to evaluate the person’s blood oxygen levels
Bronchoscopy to visualise inside of the airways and lungs
Spirometry test to measure how much air can be breathed in and out
Sputum analysis
Electromyography to measure the electrical current going through the nerves and muscles
Arterial blood gas analysis to measure carbon dioxide and oxygen
Complications
If proper diagnosis is not made without treatment, blocked airways can be dangerous or deadly.
When should an emergency department be called for help?
Seek immediate medical attention if your child experiences the following symptoms:
– Stridor that worsens within the first 4 to 8 months of age.
– Difficulty feeding, including choking or inhaling food.
– Failure to thrive with low weight gain.
– Persistent vomiting.
Call your local emergency number if your child exhibits any of the following:
– Gasping for air.
– Flaring of the nostrils during breathing.
– Visible retractions, where the child’s neck and chest pull inward with each breath.
– Cyanosis, or a bluish discoloration of the skin.
– Episodes of apnoea, characterized by pauses in breathing.
– Noticeable changes in behaviour or responsiveness.
– Loss of consciousness
Treatment of Stridor
When addressing stridor, management depends on its underlying cause. A swift initial airway assessment is crucial to determine if immediate intervention is needed.
Precautions to follow include:
– Avoiding actions that could agitate children with stridor.
– Remaining watchful for signs of rapid deterioration, indicating potential respiratory failure. Prioritizing airway securing over direct examination or manipulation of the pharynx in suspected epiglottitis cases.
– Ensuring a skilled healthcare professional accompanies the patient at all times, possibly in a controlled environment like an operating room for further airway evaluation.
– Considering foreign body aspirations in cases of sudden symptom development, such as coughing and choking in previously healthy children.
– Steer clear of beta-agonists in croup cases to avoid worsening upper airway obstruction.
– Administering antibiotics for bacterial tracheitis and epiglottitis.
– Utilizing both steroids and racemic epinephrine for managing croup effectively.
– Recognizing the need for surgical drainage in retropharyngeal and peritonsillar abscesses.
– Addressing severe conditions like laryngomalacia, laryngeal stenosis, critical tracheal stenosis, laryngeal and tracheal tumours, and foreign body aspiration through surgical correction.
Few common preventive measures
Reducing the risk of stridor involves various preventive measures. While it’s impossible to prevent all cases due to diverse causes, you can take steps to lower your risk:
– Supervise your child closely during playtime or mealtime.
– Cut food into small, manageable pieces to minimize choking hazards.
– Ensure thorough chewing of food before swallowing.
– Keep small objects out of reach of children and away from your mouth.
– Steer clear of environments with smoke or pollutants.
– Regularly clean and sanitize frequently touched surfaces and objects, such as toys.
– Maintain good hand hygiene by washing hands regularly with soap and water.
Stridor: Ayurveda perspective
Kapha, Vata and Kaphavrita Vata link
In stridor we can find that the abnormal respiratory sound has high pitch, which is obviously caused by aggravated vata trying to escape, being stuck in srotas (passages, pathways, channels) blocked by kapha. So, it may be a kaphavrita vata (kapha enveloping vata) condition. The narrowing of the tracts or respiratory passages are undoubtedly caused by accumulation of kapha (mucus, secretions).
Prana and Udana Vata link
The stridor is confined to trachea, epiglottis, larynx, pharyngeal area and around tonsils. So, the kha-vaigunya i.e. deformity and srotorodha – obstruction of channels is mainly in the kantha pradesha i.e. throat and neck. This is a junction for movement of prana and udana vata. So, stridor may be caused when kapha blocks either of these vata subtypes or interferes with their mutual chemistry in bringing about easy respiration / breathing.
Kasa link
Overproduction of phlegm is also one of the causes of stridor. So, Kaphaja Kasa can present with a cough associated with stridor. When the congestion becomes severe, the same cough may appear like vataja kasa with stridor-like sounds.
Injury to the airways can also cause stridor. So, the cough caused by injury i.e. kshataja kasa can be considered as causal of stridor in these cases. ‘Paravata iva akujan’ is one of the symptoms of a cough developed due to ‘chest injury’. It means ‘the person produces sounds from the throat and chest resembling the sounds made by a pigeon’. This probably explains sounds similar to stridor.
From the ‘causes of stridor’ perspective
Inhaling smoke or foreign objects or an allergic reaction are said to be the chief causes of stridor. Cough is a main complaint in those having stridor. The general causes of Kasa vis-à-vis cough as mentioned in Ayurveda are also the same.
From the symptoms of stridor perspective
Cough is the main symptom associated with stridor. As already discussed, the cough may be of vata or kapha types. When there is a barking type of cough producing stridor, vataja or kshayaja kasa should be considered as causal.
Drooling, muffled voice and dysphagia suggest the involvement of prana-udana vata axis.
Management of Stridor
Treating the cause of stridor is the main principle. The below mentioned treatment principles fit into addressing stridor –
– Shwasa Chikitsa – treatment of Shwasa disease (dyspnoea, shortness of breath)
– Kasa Chikitsa – treatment of cough disease, mainly kaphaja, vataja or kshataja kasa, as the case may be
– Pranavaha Sroto Dushti Chikitsa – treatment of contamination of pranavaha srotas
– Swarabheda Chikitsa – treatment of hoarseness of voice
– Shotha Chikitsa – treatment of swelling
