Respiratory Disorders

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Respiratory Disorders

• Dr Enmei Liu
• Division of Respiratory Diseases
• Childrens Hospital
• CUMS

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Respiratory disorders are important as

• They account for 50 of consultations with
  general practitioners for acute illness in young
  children and one-third of consultations in older
  children
• Respiratory illness leads to 20-35 of acute
  paediatric admissions to hospital
• They are the fifth most common cause of death in
  children ages between one and 14 years in the UK
• Asthma is the most common chronic illness of
  childhood in the UK and the most frequent single
  cause for emergency hospital admission
• Cystic fibrosis is the most common lethal
  inherited disorder in Caucasians

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Respiratory infections

• most frequent infections of childhood.
• The pre-school child has on average 6-8
  respiratory infections a year.
• Most are mild, self-limiting illness but some,
  such as bronchiolitis or epiglottitis, are
  potentially life-threatening

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Pathogens

• Viruses cause 80-90 of childhood respiratory
  infections. The most important are the
  respiratory syncycial virus (RSV), rhinoviruses,
  parainfluenza, influenza and adenovirus. An
  individual virus can cause several different
  patterns of illness, e.g. RSV can cause
  bronchiolitis, croup, pneumonia or a common cold.
  
• The important bacterial respiratory pathogens are
  Streptococcus pneumoniae and other streptococci,
  Haemophilus influenzae, Bordetella pertussis
  which cause whooping cough, and mycoplasma
  pneumoniae. Mycobacterium tuberculosis remains an
  important pathogen. Some pathogens cause
  predictable epidemics, such as RSV bronchiolitis
  every winter, whereas others, e.g. pneumococcus,
  show little seasonal variation.

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Host and environmental factors

• Poor socio-economic status (such as overcrowded,
  damp housing and poor nutrition)
• Larger family size
• Maternal smoking
• Boys more than girls
• Prematurity-especially infants who have required
  artificial ventilation
• Congenital abnormalities of the heart or lungs
• Rarely, immune deficiency, either congenital,
  e.g.agmmaglobulinaemia, or acquired, e.g.
  malignant disease or HIV infection.

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The childs age

• The childs age influences the prevalence and
  severity of infections.
• It is in infancy that serious respiratory illness
  requiring hospital admission is the most common
  and the risk of death is great.
• There is an increased frequency of infections
  when the child or older siblings start nursery or
  school. Repeated upper respiratory tract
  infections are rarely an indication of underlying
  disease

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Classification of respiratory infections

• Upper respiratory tract infection
• Laryngeal/tracheal infection
• Bronchitis
• Brochiolitis
• Pneumonia

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Upper respiratory tract infection (URTI)

• 80 of respiratory infections involve only the
  nose, throat, ears and sinuses
• The term URTI embraces a number of different
  conditions
• common cold (coryza)
• sore throat (pharyngitis, including tonsillitis)
• acute otitis media
• sinusitis

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Clinical Presentation

• The most common presentation is a child with a
  combination of a painful throat, fever, nasal
  blockage and discharge and earache.
• Cough is troublesome in many cases

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URTIs may cause

• Difficulty in feeding in infants as their noses
  are blocked and this obstructs breathing
• Febrile convulsions
• Precipitation of acute asthma
• In infants, hospital admission may be required
  exclude a more serious infection

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Brochiolitis

• Brochiolitis is the most common serious
  respiratory infection of infancy. Two to three
  per cent of all infants are admitted to hospital
  with the disease each year during annual winter
  epidemics. Ninety per cent are aged 1-9 months
  brochiolitis is rare after one year old.
  Respiratory syncitial virus (RSV) is the pathogen
  in 75-80 cases

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Clinical features

• Coryzal symptoms precede a dry cough and
  increasing breathlessness. Wheezing is often but
  not always present. Feeding difficulties
  associated with increasing dyspnoea are often the
  reason for admission to hospital. Recurrent
  apnoea is a serious complication in infants in
  the first few months of life. Infants born
  prematurely who develop bronchopulmonary
  dysplasia and infants with congenital heart
  disease are more severely affected. The finding
  on examination are characteristic
• Sharp, dry cough
• Tachypnoea
• Subcostal and intercostals recession
• Hyperinflation of the chest

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Investigations

• RSV can be identified rapidly using a fluorescent
  antibody test on nasopharyngeal secretions. The
  chest X-ray shows hyperinflation of the lungs due
  to small airways obstruction and air trapping.
  Blood gas analysis, which is required in only the
  most severe cases, shows lowered arterial oxygen
  and raised CO2 tension

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Management

• Is supportive. Humidified oxygen is delivered
  into a head-box, the concentration required is
  ascertained using a pulse oximeter. The child is
  monitored for apnoea.
• Mist, antibiotics and steroids are not helpful.
• Nebulised bronchodialators do not reduce the
  severity or duration of the illness.
• The antiviral drug ribavirin only marginally
  shortens viral excretion and clinical symptoms,
  and should be considered only for infants with
  underlying cardiopulmonary disorders or
  immunodeficiency.
• Fluids may need to be given by nasogastric tube
  or intravenously.
• Mechanical ventilation is required in about 2 of
  infants admitted to hospital

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Prognosis

• Most infants recover from he acute infection
  within two weeks. However, as many as half will
  have recurrent episodes of cough and wheeze over
  the next 3-5 years. Rarely, the illness is very
  severe and results in permanent damage o the
  airway

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Pneumonia

• A wide range of pathogens cause pneumonia in
  childhood and different organisms affect
  different age groups

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In newborns

• The newborns is infected by organisms from the
  mothers genital tract. The most common is the
  Group B ? haemolytic streptococcus. Other
  pathogens are E.coli and other Gram-negative
  bacilli. Chlamydia trachomatis is an unusual but
  important pathogen.

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In infancy

• In infancy, respiratory viruses, particularly
  RSV, are the most frequent cause but bacterial
  infection from Streptococcus pneumoniae and
  Haemophilus influenzae are also important.
  Staphylococcus aureus is uncommon but causes
  severe infection

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Older Children

• As children become older, viruses become less
  frequent pathogens and bacterial infection more
  prominent. Mycoplasma pneumoniae is a common
  cause of pneumonia in school age children.
  Tuberculosis should be considered at all ages

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Clinical Features

• Fever, cough breathlessness and lethargy
  following an upper respiratory tract infection
  are the usual presenting symptoms.
• Breathing is rapid, shallow and gives the
  impression that the child is afraid to breathe
  deeply.
• Pleuritic chest pain, neck stiffness and
  abdominal pain may be present if there is pleural
  inflammation.

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Clinical Features

• Classical signs of consolidation with impaired
  percussion, decreased breath sound and brochial
  breathing are often absent, particularly in
  infants
• The chest X-ray may slow lobar consolidation,
  patchy bronchopneumonia or, less commonly,
  cavitation of the lung.
• Pleural effusions are quite common, particularly
  in bacterial pneumonia.
• Blood cultures, nasopharyngeal aspirates of viral
  isolation and a full blood count also be
  performed in children needing hospitalisation.

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Management

• It is not possible to differentiate reliably
  between bacterial or viral infection on clinical
  or radiological grounds, so all children
  diagnosed as have pneumonia should receive
  antibiotics.
• As it is unlikely for the pathogen to be known
  when treatment is started, the choice of
  antibiotic is determined by the childs age,
  severity of illness and appearance of the chest
  X-ray.
• If intravenous therapy is required, activity
  against pneumococci, H. influenzae and Staph.
  aures can be achieved with a second-generation
  cephalosporin.

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Management

• Oral antibiotics are given for less severe
  infections.
• If M.pneumoniae or Chlamydia trachomatis
  pneumonia is suspected, erythromycin is given.
• Physiotherpy, an adequate fluid intake and oxygen
  in severe pneumonia may be required. If a child
  has recurrent or persistent pneumonia,
  investigations to exclude an underlying condition
  such as cystic fibrosis or immunodeficiency is
  indicated