PHM 456 Common Infectious Diseases of Childhood

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PHM 456Common Infectious Diseases of Childhood

• James Tjon, BSPhm, PharmD, RPh
• Department of Pharmacy
• The Hospital for Sick Children
• October 21, 2004

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Objectives

• Review the epidemiology, etiology,
  pathophysiology, clinical presentation, treatment
  and prevention associated with the following
  pediatric infectious diseases
• Croup
• Pertussis
• Bronchiolitis

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The Respiratory System
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Croup

• 4 different classifications of Croup Syndrome
• Laryngotracheitis
• Spasmodic
• Bacterial tracheitis
• Epiglottitis

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Croup

• Definition
• Involves inflammation and edema of the
• larynx, subglottic tissues and trachea,
• causing airway obstruction and is due to
• an infectious agent

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Croup

• Epidemiology
• gt 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

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Croup

• Microbiology
• Primarily viral
• Parainfluenza (types 1, 2 3)
• Influenza A B
• Adenovirus, Respiratory Syncytial Virus (RSV),
  measles
• Bacterial

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Croup

• Pathophysiology
• Begins in nasopharynx
• Spreads to larynx and trachea
• Inflammation, erythema and edema in trachea
• Subglottic area is major site of airway
  obstruction

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Croup Chest X-Ray

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Croup

• Clinical Presentation
• Gradual onset
• Duration normally 5 days
• Low grade fever
• Classic barking cough
• Hoarse voice
• Stridor
• Dyspnea
• Sore throat

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Croup

• Clinical Presentation
• Worsening of breathing difficulty
• Cyanosis
• Difficulty swallowing
• Possible hospital admission

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Croup

• Treatment
• Cold air
• Humidified air
• cool mist vaporizer
• steamy bathroom
• humidified oxygen
• Croup tents

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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

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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
• 11,000 solution (1 mg/mL)
• dose 2-5 mL q1-4 hours
• as effective as racemic epinephrine
• Side effects

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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

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Croup Canadian Study

• N Engl J Med 20043511306-13
• 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

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Pertussis

• Whooping cough syndrome
• 100 Day Cough
• Intense cough
• Epidemiology
• Seasonal, fall and winter
• Transmission by coughing
• All ages, 60 under 5 years

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Pertussis

• Microbiology
• Bordetella pertussis
• Bordetella parapertussis, Bordetella
  bronchiseptica, adenovirus

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Pertussis

• Pathophysiology
• Inhalation of organism
• Adherence to ciliated cells
• Proliferation and spread
• Paralysis of cilia
• Production and accumulation of mucous
• Possible progression to pneumonia

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Pertussis

• Complications
• Hospitalization
• Pneumonia
• Central nervous system
• encephalopathy
• seizures
• Mortality

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Pertussis Complications by Age
Cases reported to CDC 1997-2000 (N28,187)
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Pertussis

• Treatment
• Supportive
• oxygen
• suctioning
• Antibiotics

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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

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Pertussis Canadian Study

• Pediatrics 2004114(1)e96
• Randomized, multi-centre study comparing
  azithromycin and erythromycin estolate (n477, 6
  months - 16 years)
• Outcomes bacterial cultures, serology PCR,
  ADRs, compliance and symptoms
• As effective, fewer ADRs good compliance

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Pertussis

• Prevention
• Highly communicable
• Household contacts
• Same drugs as for treatment

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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

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Bronchiolitis

• Definition acute respiratory illness resulting
  from inflammation of small airways, characterized
  by wheezing and caused by viral infection

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Bronchiolitis

• Epidemiology
• Young children
• Peak incidence between 2 to 6 months
• Winter and early spring

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Bronchiolitis

• Microbiology
• Respiratory syncytial virus (RSV)
• Parainfluenza
• Influenza A B
• Adenoviruses
• Transmission by direct contamination

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Bronchiolitis

• Pathophysiology
• Viral replication in bronchioles
• Necrosis of ciliated cells
• Increased mucous secretions
• Bronchial plugging with obstruction
• Hypoxia

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Bronchiolitis

• Clinical Presentation
• Fever
• Nasal discharge
• Dry cough
• Wheeze
• Usually self-limiting
• Asthma, pneumonia, CHF, cystic fibrosis

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Bronchiolitis

• Progression
• Risk factors
• Tachypnea
• Irregular breathing
• Cyanosis or pallor
• Apnea
• Mortality

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Bronchiolitis

• Treatment
• Supportive
• oxygen
• hydration
• suctioning
• Inhaled beta-agonists (salbutamol)
• controversial
• Racemic or l-epinephrine
• vasoconstricts mucosa to reduce edema

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Bronchiolitis

• Treatment
• Corticosteroids
• oral versus inhaled
• Ribavirin
• controversial
• modest clinical benefit
• no effect on hospital stay

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Bronchiolitis

• Prevention
• Passive immunization
• given monthly through RSV season
• RSV Immune Globulin (RSV-IVIG, Respigam) blood
  product
• Palivizumab
• monoclonal antibody
• IM injection monthly during RSV season
• costly

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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

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Bronchiolitis

• Palivizumab Criteria
• Children lt 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 lt 24 months of age with hemodynamically
  significant heart disease
• Other 33-35 week gestation infants at risk,
  immune deficiency
• Canadian Paediatric Society
  Guidelines

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Bronchiolitis

• Prevention
• Active immunization
• RSV vaccine
• Being researched

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Pediatric Infectious DiseaseReferences

• Red Book
• http//www.cps.ca
• The Hospital for Sick Children Formulary
• Pediatric Dosage Handbook
• Infectious Diseases Handbook
• Nelsons Pocket Book of Pediatric Antimicrobial
  Therapy
• Nelson Essentials of Pediatrics

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QUESTIONS?