Transcript PHM 456 Common Infectious Diseases of Childhood, Part II

PHM 456
Common Infectious
Diseases of Childhood
James Tjon, BSPhm, PharmD, RPh
Department of Pharmacy
The Hospital for Sick Children
October 21, 2004
Objectives

Review the epidemiology, etiology,
pathophysiology, clinical presentation,
treatment and prevention associated with
the following pediatric infectious diseases:
 Croup
 Pertussis
 Bronchiolitis
The Respiratory System
Croup
4
different classifications of Croup
Syndrome:




Laryngotracheitis
Spasmodic
Bacterial tracheitis
Epiglottitis
Croup
 Definition
Involves inflammation and edema of the
larynx, subglottic tissues and trachea,
causing airway obstruction and is due to
an infectious agent
Croup
 Epidemiology





> 15% of respiratory tract disease in
pediatric practice
Age: 6 months to 3 years
Peak age: 2 years
More common in boys
Late fall and winter
Croup

Microbiology





Primarily viral
Parainfluenza (types 1, 2 & 3)
Influenza A & B
Adenovirus, Respiratory Syncytial Virus
(RSV), measles
Bacterial
Croup
 Pathophysiology




Begins in nasopharynx
Spreads to larynx and trachea
Inflammation, erythema and edema in trachea
Subglottic area is major site of airway
obstruction
Croup: Chest X-Ray
Croup
 Clinical








Presentation
Gradual onset
Duration normally 5 days
Low grade fever
Classic “barking” cough
Hoarse voice
Stridor
Dyspnea
Sore throat
Croup
 Clinical




Presentation
Worsening of breathing difficulty
Cyanosis
Difficulty swallowing
Possible hospital admission
Croup

Treatment


Cold air
Humidified air
• cool mist vaporizer
• steamy bathroom
• humidified oxygen

Croup tents
Croup
 Treatment

Epinephrine
• anti-inflammatory activity decreases subglottic
edema
• can improve stridor, decrease need for
hospitalization & intubation and decrease mortality
rates
• onset: 10 to 30 minutes
• duration of effect: 2 hours
Croup
 Treatment

Racemic epinephrine inhalation
• Dose: 0.5 mL of 2.25% solution in 3 mL 0.9% NaCl
q1-2h up to q20 minutes

l-epinephrine inhalation
• 1:1,000 solution (1 mg/mL)
• dose: 2-5 mL q1-4 hours
• as effective as racemic epinephrine

Side effects
Croup
 Treatment

•
Corticosteroids (moderate-severe Croup)
Dexamethasone 0.6 mg/kg IV/IM x1
• oral versus parenteral
•
Budesonide inhalation
• strong topical effects with low systemic activity
• 2 mg x1, repeated q12-24h prn
Croup: Canadian Study





N Engl J Med 2004;351:1306-13
Randomized, double-blind, multi-centre study
(n= 720 children, mild Croup)
Dexamethasone 0.6 mg/kg oral or placebo
Primary & secondary outcomes
Dexamethasone effective treatment for mild
Croup
Pertussis

Whooping cough
syndrome
 100 Day Cough
 “Intense cough”
 Epidemiology



Seasonal, fall and
winter
Transmission by
coughing
All ages, 60% under 5
years
Pertussis

Microbiology


Bordetella pertussis
Bordetella
parapertussis,
Bordetella
bronchiseptica,
adenovirus
Pertussis
 Pathophysiology:






Inhalation of organism
Adherence to ciliated cells
Proliferation and spread
Paralysis of cilia
Production and accumulation of mucous
Possible progression to pneumonia
Pertussis
 Complications



Hospitalization
Pneumonia
Central nervous system
• encephalopathy
• seizures

Mortality
Pertussis Complications by Age
Pneumonia
Hospitalization
70
60
Percent
50
40
30
20
10
0
<6 m
6-11 m
1-4 y
5-9 y
Age group (yrs)
*Cases reported to CDC 1997-2000 (N=28,187)
10-19 y
20+ y
Pertussis

Treatment
•
Supportive
• oxygen
• suctioning
•
Antibiotics
Pertussis
 Antibiotics




Erythromycin estolate 40 mg/kg/day po QID x
10-14 days
Clarithromycin 15 mg/kg/day po BID X 10
days
Azithromycin 10mg/kg/day po x 1 day, then 5
mg/kg/day po daily x 4 days
Cotrimoxazole 8 mg TMP /kg/day po BID
Pertussis: Canadian Study

Pediatrics 2004;114(1):e96
 Randomized, multi-centre study comparing
azithromycin and erythromycin estolate (n=477,
6 months - 16 years)
 Outcomes: bacterial cultures, serology & PCR,
ADRs, compliance and symptoms
 As effective, fewer ADRs & good compliance
Pertussis
 Prevention



Highly communicable
Household contacts
Same drugs as for treatment
Pertussis

Prevention



Acellular pertussis
vaccine (DTaP)
Part of routine
immunization
schedule:
Administration: 2, 4, 6
and 18 months with
booster at 4 to 6 years
Bronchiolitis
 Definition:
acute respiratory illness
resulting from inflammation of small
airways, characterized by wheezing and
caused by viral infection
Bronchiolitis
 Epidemiology



Young children
Peak incidence between 2 to 6 months
Winter and early spring
Bronchiolitis
 Microbiology





Respiratory syncytial virus (RSV)
Parainfluenza
Influenza A & B
Adenoviruses
Transmission by direct contamination
Bronchiolitis
 Pathophysiology





Viral replication in bronchioles
Necrosis of ciliated cells
Increased mucous secretions
Bronchial plugging with obstruction
Hypoxia
Bronchiolitis
 Clinical






Presentation
Fever
Nasal discharge
Dry cough
Wheeze
Usually self-limiting
Asthma, pneumonia, CHF, cystic fibrosis
Bronchiolitis
 Progression






Risk factors
Tachypnea
Irregular breathing
Cyanosis or pallor
Apnea
Mortality
Bronchiolitis
 Treatment

Supportive
• oxygen
• hydration
• suctioning

Inhaled beta-agonists (salbutamol)
• controversial

Racemic or l-epinephrine
• vasoconstricts mucosa to reduce edema
Bronchiolitis
 Treatment

Corticosteroids
• oral versus inhaled

Ribavirin
• controversial
• modest clinical benefit
• no effect on hospital stay
Bronchiolitis

Prevention

Passive immunization
• given monthly through RSV
season
• RSV Immune Globulin (RSVIVIG, Respigam): blood
product

Palivizumab
• monoclonal antibody
• IM injection monthly during
RSV season
• costly
Bronchiolitis

Palivizumab (Synagis®)





Approved in Canada in June of 2002
Formerly required Special Access Programme
authorization
Manufacturer: MedImmune Inc.
Distributor: Abbott Laboratories
Funding provided by Canadian Blood Services (CBS)
if patients meet high risk criteria
Bronchiolitis
 Palivizumab




Criteria
Children < 24 months of age with BPD/CLD and who have
required oxygen or medical treatment within 6 months of RSV
season
Premature infants born at  32 weeks gestation and aged  6
months at start of RSV season
Children < 24 months of age with hemodynamically significant
heart disease
Other: 33-35 week gestation infants at risk, immune deficiency
Canadian Paediatric Society Guidelines
Bronchiolitis
 Prevention

Active immunization
• RSV vaccine
• Being researched
Pediatric Infectious Disease
References
 Red
Book
 http://www.cps.ca
 The Hospital for Sick Children Formulary
 Pediatric Dosage Handbook
 Infectious Diseases Handbook
 Nelson’s Pocket Book of Pediatric
Antimicrobial Therapy
 Nelson Essentials of Pediatrics
QUESTIONS?