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Stridor
Stridor is a harsh sound produced by turbulent airflow through a narrowed airway. It can occur from the nose to the bronchi. Common causes in infants include laryngomalacia, vocal cord paralysis, and subglottic stenosis. Acute causes of stridor include croup, epiglottitis, foreign body inhalation, and retropharyngeal abscess. A thorough clinical exam and diagnostic imaging can help identify the specific site and cause of airway obstruction producing the stridor. Timely diagnosis and treatment are important to prevent respiratory distress.
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Stridor
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- 2. Noisy respiration producedby turbulent airflow through the narrowed passages anywhere between nasal or oral cavity to the bronchi (harsh, creaking sound) Maybe heard during inspiration, expiration or both. Common in infants because of the small diameter of their airways Subtle abnormalities can cause obstruction in newborns and infants Insipiratory Stridor Obstructive lesions of supraglottic/pharynx e.g: Laryngomalacia/ Retropharyngeal abscess Expiratory Stridor Lesions in thoracic trachea, primary and secondary bronchi e.g: Bronchial foreign body, and tracheal stenosis Biphasic Stridor Lesions in glottis,subglottis and cervical trachea e.g: Laryngeal papilomas, vocal cord paralysis and subglottis stenosis
- 3. Mechanism of developingstridor •An infant or child’s airway lumen is naturally narrower/smaller than adults. •Therefore, any minor reductions to this airway diameter (such as inflammation, mucosal edema, foreign object, collapsing epiglottis) can result in further narrowing or obstruction of the airway. •Due to this narrowing, it causes an exponential increase in airway resistance which makes it significantly difficult for the child to breathe. Stridor can occur at the following places: 1. Nose & Mouth 2. Larynx (Epiglottis, Supraglottis, Glottis,Subglottis) 3. Trachea.
- 4. Extrathoracic AirwayObstruction Usually present with symptoms of obstruction Hoarseness, brassy (“Barky”) cough, or stridor Presence of agitation, air hunger, severe retractions, cyanosis, lethargy require immediate intervention Diagnostic evaluation should include chest and lateral neck radiographs Evaluating Airway Obstruction
- 5. Aetiology-common causes ininfants and children Stridor Congenital -Laryngomalacia -Laryngeal Web -Subglottic Stenosis -Haemangioma -Vocal Cord Paralysis -Tongue and jaw abnormalities Acquired Afebrile -Papilomatosis -Injury -Foreign Body -Laryngeal Edema -Adenotonsilar hypertrophy Febrile -Epiglottis -Acute laryngitis -Laryngotracheitis -Diphtheria -Retrophargeal abscess -Infectious mononucleosis -Peritonsilar abscess
- 6. Sites and Lesions Nose Choanal atresiain newborn Tongue Macroglossia due to creatinism Dermoid at base of tongue Lingual thryroid Mandible Micrognathia Pierre-Robin syndrome Stridor- Falling back of Tongue Pharynx Congenital dermoid Adenotonsilar hypertrophy Retropharyngea l abscess Tumours
- 7. Larynx Inflammatory -Epiglottis -Laryngotracheitis -Diphtheria -Tuberculosis Neoplastic -Haemangioma -Juvenile multiple papilomas -Carcinoma in adults Traumatic -Injuriesin larynx -Foreign bodies -Oedema following endoscopy/prolong intubation Neurogenic -Laryngeal paralysis due to acquired lesions Miscellaneous -Tetanus -Tetany -Laryngismus stridulus Congenital -Laryngeal web -Laryngomalacia -Cysts -Vocal cord paralysis -Subglottic stenosis
- 8. Trachea and Bronchi Inflammatory -Tracheobronchitis Neoplastic -Tumoursof trachea Traumatic -Foreign body -Stenosis trachea(e.g:following prolonged intubation or tracheostomy Congenital -Atresia -Stenosis -Tracheomalacia
- 9. Lesions outside respiratorytract Inflammatory -Retropharyngeal & retro- oesophageal abscess Traumatic -FB oesophagus(secondary tracheal compression) Tumours -Masses in neck Congenital -Vascular rings(stridor & dysphagia) -Oesophageal atresia -Tracheo-oesophageal fistula -Congenital goitre -Cystic hygroma
- 10. ACUTE • Acute laryngo- tracheobronchitis(Croup) • Acute epiglottitis • Foreign body inhalation • Retropharyngeal abscess CHRONIC Laryngomalacia
- 11. CROUP (Laryngotracheobronchitis) Viral croupaccounts for over 95% of laryngotracheal infections. Occurs from 6 months – 6 years. (Peak incidence : 2nd year of life) Viruses : Parainfluenza (most common). : Respiratory Synctial Virus (RSV) : Influenza Mucosal inflammation and increased secretions affect the : : Larynx (glottic & subglottic regions), : Trachea : Bronchi. Potential danger because it causes critical narrowing in the child’s airways (trachea).
- 12. CLINICAL PRESENTATION Previous upperrespiratory tract infection prior to development of upper airway obstruction. Child develops “Barking” cough Hoarseness of voice Inspiratory stridor (when excited, at rest or both) Symptoms worsen at night and often recur with decreasing intensity for several days and resolve completely within a week. Agitation and crying greatly aggravate the symptoms and signs. PHYSICAL EXAMINATION : Agitated child Normal to moderately inflamed pharynx
- 13. Investigations Croup is aclinical diagnosis and does not necessarily require a radiograph of the neck. Radiographs of the neck can show the typical subglottic narrowing, or steeple sign, of croup on the posteroanterior view.
- 14. ACUTE EPIGLOTTITIS Acuteepiglottitis is a life-threatening emergency due to respiratory obstruction. Affects all children’s age group, but most common in 1- 6 years children. It is caused by H. influenzae type b. The introduction of universal Hib immunisation in many countries during infancy has led to a decrease of over 99% in the incidence of epiglottitis and other invasive H. influenzae type b infections. There is intense swelling of the epiglottis and surrounding tissues associated with septicaemia.
- 16. Clinical manifestation. Often, anotherwise healthy child suddenly develops : - Sore throat - Fever Within a few hours, patient appears : - Toxic, - Difficulty in swallowing - Labored breathing - Drooling usually present (as patient finds it painful to swallow). - Neck hyperextended to attempt to maintain airway. - Child may assume tripod position – sitting upright & leaning forward with chin up and mouth open while bracing on the arms. - Brief period of air hunger with restlessness may be followed by rapidly increasing cyanosis and coma. - Stridor – usually is a late finding and suggest that airways maybe almost completely blocked!
- 17. Investigations Laryngoscope - Performedimmediately in a controlled environment (O.T. or ICU). Lateral radiographs of the upper airway (in cases where epiglottis is thought to be the cause, but not certain). - Classic radiograph will show the “Thumb” sign. - Proper positioning of the patient crucial to avoid misinterpretation. of the film. Attempts to lie the child down or examine the throat with a spatula must not be undertaken as they can precipitate total airway obstruction and death.
- 18. FOREIGN BODY INHALATION Childrenage 1 to 3 are most like to swallow or breathe in a foreign object, such as a coin, marble, pencil eraser, buttons, beads, or other small items or foods as they are always very intrigued and interested in their surroudings.
- 19. CLINICAL PRESENTATION Choking &Coughing (common) (is present in 95% of patients presenting with foreign body aspiration) Stridor is commonly present with upper airway or upper tracheal foreign bodies. - Indicates prompt intervention required! - Approximately 50% of children have inspiratory stridor or expiratory wheezing, with prolongation of the expiratory phase, and medium-to-coarse rhonchi. Patients may present with (depending on location/degree of obstruction) : 1) Larynx - Hoarseness / aphonia - Stridor 2) Trachea - Wheezing (can mimic asthma) 3) Bronchial - Cough - Unilateral wheezing
- 20. RETROPHARYNGEAL ABSCESS Retropharyngeal abscesses aredeep neck space infections that can pose an immediate life-threatening emergency, with potential for airway compromise and other catastrophic complications
- 21. RETROPHARYNGEAL ABSCESS The retropharyngealspace can become infected in two ways : 1) Infection spreads from a contiguous area 2) Penetrating trauma (can directly inoculate the space) The "classic" retropharyngeal abscess observed in pediatric patients occurs when an upper respiratory tract infection (URTI) spreads to retropharyngeal lymph nodes, forming chains in the retropharyngeal space on either side of the superior constrictor muscle.
- 22. CLINICAL MANIFESTATION Commoncomplaints : Sore throat Fever Neck pain Neck stiffness (torticollis) Jaw stiffness (trismus) Stridor Drooling of saliva Muffled voice Sensation of lump in the throat Breathing difficulties Sometimes an upper respiratory illness can precede symptoms by weeks.
- 23. DIPHTERIA - Diphtheria isan infectious disease caused by the bacteriumCorynebacterium diphtheriae. - This disease primarily affects the mucous membranes of the respiratory tract (respiratory diphtheria), although it may also affect the skin (cutaneous diphtheria) and lining tissues in the ear, eye, and the genital areas.
- 24. CLINICAL MANIFESTATION Thesymptoms usually begin after a two- to five-day incubation period. Symptoms of respiratory diphtheria may include the following: sore throat, fever, malaise, hoarseness, difficulty swallowing, stridor difficulty breathing. With the progression of respiratory diphtheria, the infected individual may also develop an adherent gray membrane (pseudomembrane) forming over the lining tissues of the tonsils and/or nasopharynx. Individuals with severe disease may also develop neck swelling and enlarged neck lymph nodes, leading to a "bull-neck" appearance. Extension of the pseudomembrane (which consists of fibrin, bacteria, and inflammatory cells, no lipid) into the larynx and trachea can lead to obstruction of the airway with subsequent suffocation and death. (stridor and respiratory difficulty). The dissemination of diphtheria toxin can also lead to systemic disease, causing complications such as inflammation of the heart (myocarditis) and neurologic problems such as paralysis of the soft palate, vision problems, and muscle weakness.
- 25. LARYNGOMALACIA •Most common congenitallaryngeal anomaly in children. •Most common cause of stridor (approximately 60% of cases) •Stridor characteristics : - Inspiratory - Low pitched -Exacerbated by any exertion, crying, feeding. -Stridor happens due to the collapse of supraglottic structures inwards during inspiration. •Symptoms usually appear within the first 2 weeks of life •They increase in severity up to 6 months (although gradual improvement can begin at any time). •Laryngopharyngeal reflux is common.
- 27. Weak, hoarsecry Mild-moderate respiratory distress Post Intubation Injuries
- 28. Subglottic stenosis inspiratoryor biphasic stridor congenital - incomplete canalization of the subglottis and cricoid rings. Acquired - is most commonly caused by prolonged intubation. Vocal cord dysfunction unilateral vocal cord paralysis - congenital or secondary to trauma at birth or time of cardiac or intrathoracic surgery bilateral vocal cord paralysis Pt present with aphonia and a high-pitched stridor that may progress to severe respiratory distress. It is usually associated with CNS abnormalities, such as Arnold-Chiari malformation or increased intracranial pressure
- 29. Laryngeal dyskinesia, exercise-induced laryngomalacia,and paradoxical vocal fold motion are other neuromuscular disorders Laryngeal webs Laryngeal cysts Laryngeal hemangiomas (glottic or subglottic) half are accompanied by cutaneous hemangiomas in the head and neck usually regress by age 12-18 months
- 30. Laryngeal papillomas secondaryto vertical transmission of the human papilloma virus in maternal condylomata or infected vaginal cells to the pharynx or larynx of the infant during the birth Tracheomalacia most common cause of expiratory stridor Tracheal stenosis secondary to extrinsic compression
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Editor's Notes
- #4 Several anatomical and physiological features of the respiratory system in infants (age <1 yr) and young children render them susceptible to airway obstruction. The upper and lower airways are small, prone to occlusion by secretions, and susceptible to oedema and swelling. As resistance to laminar airflow increases in inverse proportion to the fourth power of the radius (Poiseuille's law), a small decrease in the radius of the airway results in a marked increase in resistance to airflow and the work of breathing. The support components of the airway are less developed and more compliant than in the adult. The ribs are cartilaginous and perpendicular relative to the vertebral column, reducing the effect of the ‘bucket handle’ movement of the rib cage. In addition, the intercostal muscles and accessory muscles of ventilation are immature. As a result, children are more reliant on the diaphragm for inspiration. Increased respiratory effort causes subcostal and sternal recession, and the mechanical efficiency of the chest wall is reduced. Higher metabolic rate and increased oxygen demand mean children with airway compromise can deteriorate very quickly. Also, with a smaller functional residual capacity and fewer fatigue-resistant fibres in the diaphragm, there is little respiratory reserve at times of stress.1
- #11 There are many causes of stridor in children. However, certain causes are very common, and can be categorised according to the location/site of obstruction. They can also be classified as Acute or Chronic causes. Clinical manifestation, treatment and management will depend on the cause determined.
- #12 Affects the glottic (middle part of larynx that contains voice box) and subglottic regions bottom part of larynx). Most patients have an upper respiratory tract infection with some comination of rhinorrhea, pharyngitis, mild cough, and low grade fever for about 1-3 days prior to the development of upper airway obstruction. The child then develops the characteristic “barking
- #13 PREVIOUS URTI : Cough, low grade fever, coryza, rhinorrhea, pharyngitis for 1-3 days approx before developing barking cough, stridor.
- #14 ****However, the steeple sign may be absent in patients with croup, may be present in patients w/out croup as a normal variant, and may rarely be present in patients with epiglottis. Hence, they don’t correlate well with disease severity.
- #16 As with many other aspects of the pediatric airway, the epiglottis is significantly different in the child from in the adult. In the infant, the epiglottis is located more anteriorly and superiorly than in the adult, and it is at a greater angle with the trachea. It is also more omega shaped and floppy than the more rigid, U-shaped epiglottis in the adult.
- #20 Patients may present with (depending on location/degree of obstruction) : Respiratory distress, pneumonia, pulmonary edema, or wheezing. Tachypnea; nasal flaring; intercostal, subcostal, and suprasternal retractions; and differences in percussion between hemithoraces also are common findings. Fever and central cyanosis are less common. Only rarely do children with a positive history have an examination with completely normal findings.
- #21 A schematic of the anatomy of the deep spaces of the neck, as illustrated in lateral and cross-sectional views. The fascial planes, defined by the color key, surround the potential spaces. The retropharyngeal space is bounded anteriorly by the buccal pharyngeal fascia, which invests the pharynx, trachea, esophagus, and thyroid. The retropharyngeal space is bounded posteriorly by the alar fascia and laterally by the carotid sheaths and parapharyngeal spaces. It extends from the base of the skull to the mediastinum at the level of the tracheal bifurcation. Note the danger space located between the alar fascia and the prevertebral fascia.
- #32 Conclusion : Summarise what is stridor and what symptoms to look for in the child….mention all the clinical features one by one and emphasize on the importance.