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.

1. Kabilan Naidu Krishnan
Stridor

2. Noisy respiration produced by 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 developing stridor
•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 Airway Obstruction
 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 in infants 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
atresia in
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
-Injuries in 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
-Tumours of trachea
Traumatic
-Foreign body
-Stenosis
trachea(e.g:following
prolonged intubation or
tracheostomy
Congenital
-Atresia
-Stenosis
-Tracheomalacia

9. Lesions outside respiratory tract
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 croup accounts 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 upper respiratory 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 a clinical 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
 Acute epiglottitis 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, an otherwise 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
- Performed immediately
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
Children age 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 are deep neck space
infections that
can pose an immediate life-threatening emergency, with
potential for airway compromise and other catastrophic
complications

21. RETROPHARYNGEAL
ABSCESS
 The retropharyngeal space 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
 Common complaints :
 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 is an 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
 The symptoms 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 congenital laryngeal 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, hoarse cry
 Mild-moderate respiratory
 distress
Post Intubation Injuries

28. Subglottic stenosis
 inspiratory or 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
 secondary to 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

31. CONCLUSION