Pediatrics - Dr. Tara – Lecture 4 – Respiratory Infections

Pediatrics - Dr. Tara – Lecture 4 – Respiratory Infections
Airway is divided into 3 anatomic parts
1. Extrathoracic airway ; from the nose to the thoracic inlet
2. Intrathoracic-extrapulmonary airway ; from the thoracic inlet to the main stem bronchi
3. Intrapulmonary airway is within the lung parenchyma
SIGN
INTRATHORACICEXTRATHORACIC
EXTRAPULMONARY
AIRWAY
AIRWAY
OBSTRUCTION
OBSTRUCTION
INTRAPULMONARY
PARENCHYMAL
AIRWAY
PATHOLOGY
OBSTRUCTION
Tachypnea
+
+
++
++++
Retractions
++++
++
++
+++
Stridor
++++
++
−
−
Wheezing
?
+++
++++
?
Grunting
?
?
++
++++
Cough; results from stimulation of irritant receptors located in the airway mucosa including the ear
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Causes of Acute Cough;
1.
2.
3.
4.
Acute respiratory infection.
Pulmonary edema.
Chemical irritation.
Foreign body aspiration
Causes of chronic cough;
1.
2.
3.
4.
5.
Allergy ( asthma, allergic rhinitis)
Anatomical abnormality ( tracheo
tracheo-esophageal
esophageal fistula, Gastroesophageal reflux).
Chronic infection; cystic fibrosis
fibrosis, and Immunodeficiency.
Environmental exposure
Ticks.
Croup (Laryngotracheobronchitis)
Laryngotracheobronchitis)
•
•
•
It is acute infectious laryngotrachiobronchitits.
parainfluenza virus type 1 and 2 are the most common agents
Usually affects children between6 months
months-3 years,
Clinical presentation;
•
•
•
•
•
•
tractt infection(common cold) ,
Starts by symptoms of upper respiratory trac
Then a brassy cough typically sounding like a barking seal
Then inspiratory stridor and respiratory distress
Symptoms are characteristically worse at night and often recur with decreasing intensity,
until about 1 wk
Most cases are mild and self limited,
Rarely there may be very sever airway obstruction necessitating artificial airway
Examination;
1. suprasternal, intercostal and subcostal retractions,.
2. There may also be associated lower airway obstruction manifested by wheeze or expiratory
rhonchi
3. PA XR ; (Steeple) sign of narrowed subglottic space.
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Treatment;
1. Aerosolized raceme epinephrine reduces edema temporarily(about 2 hours), in sever cases
it may need to be repeated every 20 minutes. A case needing this treatment needs hospital
admission
2. Corticosteroids ; systemic or inhaled
3. dexamethasone (0.15 mg/kg) single dose
4. helium-oxygen mixture (Heliox) may be effective in children with severe croup for whom
intubation is being considered
Antibiotics not indicated
Over the counter cold medication not indicated
Indications for hospital admission;
1.
2.
3.
4.
5.
6.
7.
8.
Progressive stridor
Severe stridor at rest
Respiratory distress
Hypoxia
Cyanosis
Depressed mental status
Poor oral intake
Need for reliable observation
Epiglottitis
•
•
•
•
Pediatric emergency
Inflammation of the epiglottis and/or the supraglottic tissues surrounding the epiglottis
predominantly bacterial ( H. influenzae type b).
Usually in children between 2-7 years
Otolaryngologist or general surgeon and anesthesiologist should be consulted
Clinical presentation;
1.
2.
3.
4.
5.
6.
Sudden onset
High fever
Respiratory distress
Fulminate progression
Sever dysphagia and a muffled voice
Patients usually sit erect and they may drool from there mouth because of dysphagia
Diagnosis;
1. Thumb sign on lateral neck x-ray differentiates epiglottitis from sever croup
2. Laryngoscope examination to inspect the epiglottis which shows cherry red enlargement
3. Blood culture and culture from the surface of the epiglottis
Treatment;
1. Endotracheal intubation is the preferred method of treatment. most patient can be safely
extubated with in 48-72 hours
2. Antibiotics ( ceftriaxon) should be given.
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3. All patients should receive oxygen unless the mask causes excessive agitation
4. Racemic epinephrine
ine and corticosteroids are ineffective
5. Minor procedures, such as intravenous access, may cause respiratory distress and can be
performed more safely after intubation
Examination of the tonsills by toungue depresser is contraindicated unless in operative
theater.
Bronchiolitis
•
•
•
•
•
•
•
Is predominantly a viral disease.
RSV is responsible for >50% of cases
Other agents include parainfluenza adenovirus, mycoplasma
Occur in winter or early spring
Older family members are a common source of infection; they might only experience minor
upper respiratory symptoms (colds)
Host anatomic and immunologic factors play a significant role in the severity
Co-infection
infection with >1 virus can also alter the clinical manifestations and/or severity of
presentation
Clinical presentation;
•
•
•
•
•
hinorrhea, cough, and low grade fever,
Rhinorrhea,
Followed in several days with the onset of rapid breathing and wheezing.
The child may feed poorly and may have sleeping disturbance.
Acute symptoms last for 55-6 days,
Recovery is complete usually after 10
10-14 days
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Examination;
1.
2.
3.
4.
5.
dyspnea,
intercostal and subcostal retraction,
Tachypnea
prolonged expiratory phase,
in very sever cases there may be cyanosis
Differential diagnosis;
1.
2.
3.
4.
5.
Congenital malformations; vascular ring, left ventricular enlargment, intrinsic abnormality
Foreign body aspiration
Gastroesophageal reflux
Trauma; aspirations, burns, or scalds of the tracheobronchial tree
tumors
Diagnosis;
m be
1. CXR; typically shows air trapping and may show peribronchial, thickening, there may
atelectasis, or infiltrates
2. WBC count is usually normal
3. RSV may be isolated from nasopharyngeal secretions by PCR,culture
4. Hypoxemia may occur secondary to ventilation perfusion mismatch.
5. Hypercapnia is rare occurring in severely affected infants wit
with
h sever airway obstruction and
respiratory fatigued
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Treatment;
1. Oxygen; Humidified oxygen should be given to maintain oxygen saturation of more than
93%.
2. Bronchodilators; such as aerosolized beta agonist or racemic epinephrine may be beneficial
in selected patients
3. Mechanical ventilation; required to treat respiratory failure or apnea.
4. Monthly injections of RSV monoclonal antibodies for infants and toddlers under 2 years with
bronchopulmonary dysplasia
5. Supportive measures; Intravenous fluid, if there is poor oral intake
6. Corticosteroids; offer little benefit.
7. Antibiotics; are not indicated unless there is evidence of secondary bacterial infection
8. Ribavirin aerosol; a specific antiviral agent RSV it has been demonstrated to be mildly
effective. It is considered in patients with high risk disease
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