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Respiratory

Dr. Mohi

“ URT OBSTRUCTION ”

 

Total Lec: 30


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Infectious Upper Airway Obstruction

Prof. Muhi K. Al-Janabi

MRCPCH; DCH; FICMS
Consultant Pediatric Pulmonologist


Objectives

1.  Know  and  understand  the  aetiology  and  natural  history  of  URTI  including

knowledge of the common causative organisms.

2.  Be able

to advise parents about how to care for a child with an URTI

Viral croup

184394195

Objectives

1.  Know and understand the aetiology and natural history of viral croup including

knowledge of the common causative organisms.

2.  Know the management options available, including drugs, oxygen and supportive

therapy.

3.  Be able to make a confident differential diagnosis for the various causes of upper

airway obstruction.

4.  Be able to advise parents about how to care for a child with viral croup.

Epiglottitis
Objectives

1.  Be able to recognize the clinical features of epiglottitis.
2.  Be able to distinguish epiglotittis from other causes of upper airway obstruction.
3.  Know the management options available, including intubation, drugs, oxygen and

supportive therapy.

4.  Be able to advise parents about how to care for a child with a bronchiolitis.

Bacterial tracheitis

Objectives

 

1.  Be able to recognize the clinical features of bacterial tracheitis .
2.  Know the management options available, including intubation, drugs, oxygen and

supportive therapy.



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ETIOLOGY AND EPIDEMIOLOGY

1.  Viral agents account for most acute infectious upper airway obstructions.
2.  The exceptions are diphtheria, bacterial tracheitis, and epiglottitis.
3.  The parainfluenza viruses (types 1, 2, and 3; account for ≈75% of cases;

other viruses associated with this disease include influenza A and B,
adenovirus, respiratory syncytial virus (RSV), and measles.

4.  Most patients with croup are between the ages of 3 mo and 5 yr, with the

peak in the 2nd yr of life.

5.  The incidence of croup is higher in males;
6.  It occurs most commonly in the late fall and winter but may occur

throughout the year.

7.  Approximately 15% of patients have a strong family history of croup.
8.  In the past, Haemophilus influenzae type b was the most commonly

identified etiology of acute epiglottitis. Since the widespread use of the
HiB vaccine, invasive disease due to H. influenzae type b in pediatric
patients has been reduced by 80–90%.

CLINICAL MANIFESTATIONS

Croup (Laryngotracheobronchitis):

1.  Most patients have an upper respiratory tract infection with some

combination of rhinorrhea, pharyngitis, mild cough, and low-grade fever
for 1–3 days before the signs and symptoms of upper airway obstruction
become apparent.

2.  The child then develops the characteristic “barking” cough, hoarseness,

and inspiratory stridor.

3.  The low-grade fever may persist, although temperatures may reach 39–

40°C. Some children are afebrile.

4.  Symptoms are characteristically worse at night and often recur with

decreasing intensity for several days and resolve completely within a wk.

5.  Agitation and crying greatly aggravate the symptoms and signs.
6.  The child may prefer to sit up in bed or be held upright.
7.  Older children usually are not seriously ill.

 

 


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Physical examination

1.  may reveal a hoarse voice, coryza, normal to moderately inflamed

pharynx,

2.  and a slightly increased respiratory rate.
3.  Rarely, the upper airway obstruction progresses and is accompanied by

an increasing respiratory rate; nasal flaring; suprasternal, infrasternal,
and intercostal retractions; and continuous stridor.

4.  alveolar gas exchange is usually normal. Hypoxia and low oxygen

saturation are seen only when complete airway obstruction is imminent.

5.  The child who is hypoxic, cyanotic, pale, or obtunded needs immediate

airway management.

6.  Occasionally, the pattern of severe laryngotracheobronchitis is difficult to

differentiate from epiglottitis, despite the usually more acute onset and
rapid course of the latter.

7.  Radiographs of the neck may show the typical subglottic narrowing or

“steeple sign” of croup on the posteroanterior view . Radiographs should
be considered only after airway stabilization in children who have an
atypical presentation or clinical course. Radiographs may be helpful in
distinguishing between severe laryngotracheobronchitis and epiglottitis,
but airway management should always take priority.

Acute Epiglottitis (Supraglottitis):

1.  This dramatic, potentially lethal condition is characterized by an acute

potentially fulminating course of high fever, sore throat, dyspnea, and
rapidly progressing respiratory obstruction.

2.  Often, the otherwise healthy child suddenly develops a sore throat and

fever.

3.  Within a matter of hours, the patient appears toxic, swallowing is

difficult, and breathing is labored.

4.  Drooling is usually present and the neck is hyperextended in an attempt

to maintain the airway. The child may assume the tripod position, sitting
upright and leaning forward with the chin up and mouth open while
bracing on the arms.

5.  A brief period of air hunger with restlessness may be followed by rapidly

increasing cyanosis and coma.

6.  Stridor is a late finding and suggests near-complete airway obstruction.

Complete obstruction of the airway and death can ensue unless adequate
treatment is provided.

7.  The barking cough typical of croup is rare.


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8.  Usually, no other family members are ill with acute respiratory

symptoms.



Diagnosis

1.  The diagnosis requires visualization of a large, “cherry red” swollen

epiglottis by laryngoscopy.

2.  . In a patient in whom the diagnosis is certain or probable based on

clinical grounds, laryngoscopy should be performed expeditiously in a
controlled environment such as an operating room or intensive care unit.

3.  Anxiety-provoking interventions such as phlebotomy, intravenous line

placement, placing the child supine, or direct inspection of the oral cavity
should be avoided until the airway is secure

4.  . If epiglottitis is thought to be possible but not certain in a patient with

acute upper airway obstruction, the patient can undergo lateral
radiographs of the upper airway first. Classic radiographs of a child who
has epiglottitis show the “thumb sign”.

5.  A physician skilled in airway management and use of intubation

equipment should accompany patients with suspected epiglottitis at all
times.

6.  Establishing an airway by nasotracheal intubation or, less often, by

tracheostomy is indicated in patients with epiglottitis, regardless of the
degree of apparent respiratory distress, because as many as 6% of
children with epiglottitis without an artificial airway die, compared with
<1% of those with an artificial airway.

7.  In general, children with acute epiglottitis are intubated for 2–3 days,

because the response to antibiotics is usually rapid.

8.  Most patients have concomitant bacteremia; occasionally, other

infections are present, such as pneumonia, cervical adenopathy, or otitis
media. Meningitis, arthritis, and other invasive infections with H.
influenzae
type b are rarely found in conjunction with epiglottitis.

Acute Infectious Laryngitis:

1.  Laryngitis is a common illness.
2.  Viruses cause most cases; diphtheria is an exception but is extremely

rare in developed countries .

3.  The onset is usually characterized by an upper respiratory tract infection

during which sore throat, cough, and hoarseness appear.


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4.  The illness is generally mild; respiratory distress is unusual except in the

young infant.

5.  Hoarseness and loss of voice may be out of proportion to systemic signs

and symptoms.

6.  The physical examination is usually not remarkable except for evidence

of pharyngeal inflammation.

7.  Inflammatory edema of the vocal cords and subglottic tissue may be

demonstrated laryngoscopically.

8.  The principal site of obstruction is usually the subglottic area.

Spasmodic Croup :

1.  Spasmodic croup occurs most often in children 1–3 yr of age
2.  clinically similar to acute laryngotracheobronchitis, except that the

history of a viral prodrome and fever in the patient and family are
frequently absent.

3.  Laryngoscopy reveals pale, watery edema with preservation of the

epithelium (unlike the erythematous edema and destruction of the
epithelium of acute infectious laryngotracheobronchitis).

4.  Occurring most frequently in the evening or nighttime,
5.  spasmodic croup begins with a sudden onset
6.  The child awakens with a characteristic barking, metallic cough, noisy

inspiration, and respiratory distress and appears anxious and frightened.

7.  The patient is usually afebrile.
8.  Usually, the severity of the symptoms diminishes within several hr, and

the following day, the patient often appears well

9.  Similar, but usually less severe, attacks without extreme respiratory

distress may occur for another night or 2.

10. 

Such episodes often recur several times


DIFFERENTIAL DIAGNOSIS:

1.  Bacterial tracheitis ; an acute bacterial infection of the upper airway,

does not involve the epiglottitis but, like epiglottitis and croup, is capable
of causing life-threatening airway obstruction. Staphylococcus aureus is
the most commonly isolated pathogen. Moraxella catarrhalis, non-typable
H. influenzae,
and anaerobic organisms have also been implicated. is the
most important differential diagnostic consideration.

2.  Diphtheritic croup is extremely rare in developed countries. Early

symptoms of diphtheria include malaise, sore throat, anorexia, and low-
grade fever. Within 2–3 days, pharyngeal examination reveals the typical


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gray-white membrane, which may vary in size from covering a small
patch on the tonsils to covering most of the soft palate. The membrane is
adherent to the tissue, and forcible attempts to remove it cause bleeding.
The course is usually insidious, but respiratory obstruction can occur
suddenly

3.  Measles croup Almost always coincides with the full manifestations of

systemic disease and the course may be fulminant .

4.  Foreign body Sudden onset of respiratory obstruction can be caused by

aspiration of a foreign body ,the child is usually 6 mo–3 yr of age. Choking
and coughing occur suddenly, usually without prodromal signs of
infection, although children with a viral infection can also aspirate a
foreign body.

5.  A retropharyngeal or peritonsillar abscess can mimic respiratory

obstruction CT scans of the upper airway are essential in evaluating
these possibilities. Other possible causes of upper airway obstruction
include extrinsic compression of the airway (vascular ring) and
intraluminal obstruction from masses (laryngeal papilloma, subglottic
hemangioma); these tend to have chronic or recurrent symptoms.

6.  angioedema of the subglottic areas as part of anaphylaxis and

generalized allergic reactions,

7.  Edema after endotracheal intubation hypocalcemic tetany,
8.  Infectious mononucleosis
9.  trauma
10. 

Malformations of the larynx.

11. 

Early sign of asthma.

12. 

Vocal cord dysfunction

13. 

Accidental ingestion of very hot liquid.

COMPLICATIONS:

1.  Complications occur in ≈15% of patients with viral croup.
2.  The most common is extension of the infectious process to involve other

regions of the respiratory tract, such as the middle ear, the terminal
bronchioles, or the pulmonary parenchyma.

3.  Bacterial tracheitis may be a complication of viral croup rather than a

distinct disease. If associated with S. aureus, toxic shock syndrome may
develop.

4.  Pneumonia, cervical lymphadenitis, otitis media, or, rarely, meningitis or

septic arthritis can occur in the course of epiglottitis.

5.  Mediastinal emphysema and pneumothorax are the most common

complications of tracheotomy. 


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TREATMENT:

1.  The mainstay of treatment for children with croup is airway

management.

2.  Treatment of the respiratory distress should take priority over any

testing.

3.  Most children with either acute spasmodic croup or infectious croup can

be managed safely at home. Mist has been traditionally used to treat
croup. Given the risk of burns and the observation that cold night air is
also beneficial led to the use of cool mist

4.  Nebulized racemic epinephrine is an accepted treatment for moderate or

severe croup. The mechanism of action is believed to be constriction of
the precapillary arterioles through the β-adrenergic receptors, causing
fluid resorption from the interstitial space and a decrease in the laryngeal
mucosal edema. Traditionally, racemic epinephrine, a 1 : 1 mixture of the
d- and l-isomers of epinephrine, has been administered. A dose of 0.25–
0.75 mL of 2.25% racemic epinephrine in 3 mL of normal saline can be
used as often as every 20 min. The indications for the administration of
nebulized epinephrine include moderate to severe stridor at rest, the
possible need for intubation, respiratory distress, and hypoxia. The
duration of activity of racemic epinephrine is <2 hr. Therefore,
observation is mandated. The symptoms of croup may reappear, but
racemic epinephrine does not cause rebound worsening of the
obstruction.

5.  Patients can be safely discharged home after a 2–3 hr period of

observation provided they have no stridor at rest; have normal air entry,
normal color, and normal level of consciousness; and have received
steroids .

6.  Nebulized epinephrine should still be used cautiously in patients with

tachycardia, heart conditions such as tetralogy of Fallot, or ventricular
outlet obstruction because of possible side effects.

7.  The effectiveness of oral corticosteroids in viral croup is well established.

Corticosteroids decrease the edema in the laryngeal mucosa through
their anti-inflammatory action. Oral steroids are beneficial, even in mild
croup, as measured by reduced hospitalization, shorter duration of
hospitalization, and reduced need for subsequent interventions such as
epinephrine administration. Most studies that demonstrated the efficacy
of oral dexamethasone used a single dose of 0.6 mg/kg; a dose as low as
0.15 mg/kg may be just as effective. Intramuscular dexamethasone and
nebulized budesonide have an equivalent clinical effect; oral dosing of
dexamethasone is as effective as intramuscular administration.

8.  Antibiotics are not indicated in croup.


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9.  A helium-oxygen mixture (Heliox) may be effective in children with

severe croup who may need intubation.

10. 

Children with croup should be hospitalized for any of the following:

progressive stridor, severe stridor at rest, respiratory distress, hypoxia,
cyanosis, depressed mental status, poor oral intake, or the need for
reliable observation.

11. 

Epiglottitis is a medical emergency and warrants immediate

treatment with an artificial airway placed under controlled conditions,
either in an operating room or intensive care unit.

12. 

All patients should receive oxygen en route unless the mask causes

excessive agitation.

13. 

Racemic epinephrine and corticosteroids are ineffective.

14. Cultures of blood, epiglottic surface, and, in selected cases, cerebrospinal

fluid should be collected after airway stabilization.

15. 

Ceftriaxone or cefotaxime should be given parenterally, pending

culture and susceptibility reports, because from 10–40% of H. influenzae
type b cases are resistant to ampicillin.

16. 

After insertion of the artificial airway, the patient should improve

immediately, and respiratory distress and cyanosis should disappear.

17. 

Epiglottitis resolves after a few days of antibiotics, and the patient

may be extubated; antibiotics should be continued for 7–10 days.

18. 

Tracheotomy and Endotracheal Intubation:Endotracheal

intubation or tracheotomy is required for most patients with bacterial
tracheitis and all young patients with epiglottitis. It is rarely required for
patients with laryngotracheobronchitis, spasmodic croup, or laryngitis.
Severe forms of laryngotracheobronchitis that require intubation in a
high proportion of patients have been reported during severe measles
and influenza A virus epidemics. Assessing the need for these procedures
requires experience and judgment because they should not be delayed
until cyanosis and extreme restlessness have developed .The
endotracheal tube or tracheostomy must remain in place until edema and
spasm have subsided and the patient is able to handle secretions
satisfactorily. It should be removed as soon as possible, usually within a
few days. Adequate resolution of epiglottic inflammation that has been
accurately confirmed by fiberoptic laryngoscopy, permitting much more
rapid extubation, often occurs within 24 hr. Racemic epinephrine and
dexamethasone (0.5 mg/kg/dose every 6 hr as needed) may be useful in
the treatment of croup associated with extubation.

 

 


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PROGNOSIS:

1.  In general, the length of hospitalization and the mortality rate for cases of

acute infectious upper airway obstruction increase as the infection
extends to involve a greater portion of the respiratory tract, except in
epiglottitis, in which the localized infection itself may prove to be fatal.

2.  Most deaths from croup are caused by a laryngeal obstruction or by the

complications of tracheotomy. Rarely, fatal out-of-hospital arrests due to
viral laryngotracheobronchitis have been reported, particularly in infants
and those patients whose course has been complicated by bacterial
tracheitis.

3.  Untreated epiglottitis has a mortality rate of 6% in some series, but if the

diagnosis is made and appropriate treatment is initiated before the
patient is moribund, the prognosis is excellent.

4.  The outcome of acute laryngotracheobronchitis, laryngitis, and

spasmodic croup is also excellent.




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