Acute Respiratory Infections Case Definitions

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Acute Respiratory InfectionsCase Definitions

• Dr Claudia Turner
• Research Paediatrician
• SMRU

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Case Definitions

• Pneumonia
• Children Infants
• Adults
• Avian Influenza

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Children and Infants

• Pneumonia

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Diagnosis of Pneumonia in Children

• Is difficult!

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Diagnosis of Pneumonia in Children

• The best individual way of ruling out pneumonia
  is the absence of tachypnoea
• Symptoms that support a diagnosis of pneumonia
• Difficulty in breathing
• Fever
• Difficulty in feeding
• Restlessness

Margolis, P. and A. Gadomski. Jama, 1998. 279(4)
308-13 Adegbola, R.A. and S.K. Obaro. Ann Trop
Med Parasitol, 2000. 94(3) 197-207
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Diagnosis of Pneumonia in Children

• The presence of either a RR gt50 breaths/min or
  chest indrawing, or both, was a good indication
  that a child had pneumonia
• The presence of auscultatory signs increases the
  specificity but lowers the sensitivity

Harari, M., et al. Lancet 1991 338(8772)
928-30 Zar,H.J., Current opinion pulmonary
medicine, 2004. 10,176-82
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Determining Severity

• Criteria for diagnosis of severe ARI requiring
  hospitalization included one or more of the
  following
• Tachypnoea
• Chest retractions
• Cyanosis
• Convulsions
• Inability to drink

Sunakorn, P., et al. Pediatr Infect Dis J, 1990.
9(12) 873-7
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Case Definition

• Smallest number of criteria
• Fever not always present and not specific
• Auscultation not reliable in children
• Respiratory rate is the corner stone of diagnosis
• Confirmed by many studies performed across the
  developing world

Technical basis for the WHO recommendations on
the management of pneumonia in children at
first-level health facilities, 1991
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Unwell child or infant with cough or difficulty
in breathing
Count respiratory rate over 1 minute
No
Does the infant have indrawing of the chest wall?
Pneumonia
Yes
Does the infant have any of the
following? Central cyanosis off oxygen Severe
respiratory distress Inability to drink
No
Yes
Very Severe Pneumonia
Severe Pneumonia
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Adults

• Pneumonia

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CURB 65 Scoring System

• Six point scoring system (0-5), giving one point
  for each of the following
• Confusion
• Urea gt7 mmol/l
• RR 30/min
• Low BP
• Age 65
• A score of three or more is significant
• Sensitivity and specificity of about 80

WS Lim et al Thorax 200358 377-382
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CRB - 65

• Further modification for use in the community
• Excellent correlation with CURB - 65

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Fever (38C), cough and abnormal chest findings
Pneumonia
Score one for each clinical features
Confusion Respiratory Rate over 1 minute gt
30 Diastolic Pressure lt60mmHg Age gt 65 years
0
3 - 4
1 - 2
Severe Pneumonia
Pneumonia
Moderate Pneumonia
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Avian Influenza(AI)
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Case Definitions

• Person under investigation
• Suspected cases
• Probable cases
• Confirmed case

Require notification to WHO
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Suspected H5N1 case

• A person presenting with unexplained acute lower
  respiratory illness with fever (gt38 ºC ) and
  cough, shortness of breath or difficulty
  breathing
• AND

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One or more of the following exposures in the 7
days prior to the onset of symptoms

• Close contact with a person who is a suspected,
  probable, or confirmed H5N1 case
• Exposure to poultry or wild birds, their remains
  or their faeces in an area where H5N1 infections
  have been suspected or confirmed in the last month

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• Consumption of raw or undercooked poultry
  products in an area where H5N1 infections have
  been suspected or confirmed in the last month
• Close contact with a confirmed H5N1 infected
  animal other than poultry or wild birds
• Handling samples suspected of containing H5N1
  virus in a laboratory or other setting

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Probable H5N1 case

• Probable definition 1
• A person meeting the criteria for a suspected
  case
• AND
• One of the following additional criteria
• Infiltrates or evidence of an acute pneumonia on
  chest radiograph plus evidence of respiratory
  failure (hypoxaemia, severe tachypnoea)
• OR
• Positive laboratory confirmation of an influenza
  A infection but insufficient laboratory evidence
  for H5N1 infection

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• Probable definition 2
• A person dying of an unexplained acute
  respiratory illness who is considered to be
  epidemiologically linked by time, place, and
  exposure to a probable or confirmed H5N1 case

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Confirmed H5N1 case

• A person meeting the criteria for a suspected or
  probable case
• AND
• Positive H5 PCR results from tests using two
  different PCR targets, e.g. primers specific for
  influenza A and H5 haemagglutinin

Other tests can be used but are not available
in the SMRU lab
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Thank You