Journal Reading

1
Journal Reading

• Occult Pneumonias
• ---Richard Bachyr, MD Holly Perry, MD Marvin
  B Harper, MD
• ---Annals of Emergency Medicine

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INTRODUCTION

• Young children offer suboptimal examinations, and
  clinical signs and symptoms in infants and
  children are frequently too nonspecific to
  suggest, or disqualify , a diagnosis.
• Diagnostic evaluations ten to be more extensive
  in young children with high fever and no
  identifiable infectious source.
• WBC counts have been recommended in young
  children with high fever as part of a diagnostic
  screen.

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INTRODUCTION

• Study objective
• To determine the incidence of radiographic
  findings of pneumonia in highly febrile children
  with leukocytosis and no clinical evidence of
  pneumonia or other major infectious source

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Material and Methods

• Clinical practice guidelines for obtaining chest
  radiographs in young febrile
• children Division of Emergency
• Medicine of Childrens Hospital in
• Boston, Massachusetts

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Material and Methods

• These guidelines offered no recommendation as to
  whether WBC count should be determined in a
  particular patients these guidelines offered no
  specific recommendations for the use of chest
  radiography in children with WBC counts less than
  20,000/mm3

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Material and Methods

• To avoid seasonal variation, we colleted data for
  an entire year after adoption of the guidelines.
• All records of ED patients with leukocytosis (
  WBC count 20,000/mm3), triage temperature
  39.0C or higher, and age 5 years or younger were
  reviewed daily for 12 consecutive months
  beginning December 15, 1994.
• Physicians primarily involved in the ED
  evaluation of a patient with leukocytosis
  completed a questionnaire

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Material and Methods

• Questionnaire indicating
• Diagnosis
• generalappearance( well, ill, toxic),
• presence of respiratory symptoms ( breathing
  difficulty, congestion, wheeze, occasional or
  slight cough, mafor complaint of cough),
• presence of respiratory signs (congestion,
  observed
• cough, tachypnea, grunting, nasal flaring,
  retractions,
• rhonchi, wheezing, rales, focal area of
  decreased breath,
• sounds),
• the presence and duration of fever,
• reason for chestradiography, if performed ,
• the interpretation of the chest radiograph by
  the radiologist.

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Material and Methods

• The clinicians were expected to complete the
  questionnaire
• during the ED evaluation. Missing questionnaire
  were
• completed by means of telephone interview ( by
  one of the
• authors) and review of the medical record. (
  within 24 hours of
• the visit)
• Patients were considered eligible for a chest
  radiograph if
• 1. aged 5 years or younger, leukocytosis, a
  triage temperature
• of 39.0ºC or higher
• 2. no other major source of infection (eg,
  abscess, adenitis, appendicitis, bloody diarrhea,
  celulitis, aseptic or bacterial
• meningitis, osteomyelitis, parotitis,
  pyelonephritis, septic
• arthritis)
• 3. no immunodeficiency (sickle cell disease,
  neoplasia, long-term stroid use, HIV infection)

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Material and Methods

• 4. no chronic lung disease ( asthma, cystic
  fibrosis,
• bronchopulmonary dysplasia, congesstive heart
• failure, chronic aspiration pneumonia)
• 5. pt with minor infections such as otitis
  media,
• sinusitis, and pharyngitis were still considered
  
• 6. pt with identifiable viral illnesses such as
  
• mononucleosis, stomatitis, varicella,
  bronchiolitis,
• and croup were also considered
• 7. pt with a preliminary diagnosis of UTI or
• appendicitis who were proved not to have these
• illnesses were considered

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Material and Methods

• Medical record was reviewed for age, initial
  temperature, triage respiratory rate, oxygen
  saturation, disposition, final diagnosis, culture
  results, and attending pediatric radiologists
  repost on the chest radiograph.
• Tachypnea determined on the basis of respiratory
  rate
• lt 6 m/o? 60/min
• 612 m/o? 50/min
• 1 3 y/o? 40/min
• gt 3 y/o? 25/min
• Temporature lt1 y/o rectal measurements
• gt1y/o ---tympanic membrane

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Material and Methods

• On the questionnaire, the clinician had to select
  1 of 4
• choices as the indication for chest radiography
  
• fever and respiratory symptoms or signs
  suggestive of pneumonia
• Fever and leukocytosis but no bacterial focus
• Fever, leukocytosis, and only a minor bacterial
  source of
• infection
• inadvertent chest radiography (eg, pneumonia
  found on an abdominal radiograph)
• 2, 3, 4 ? empiric chest radiographs , no-signs
  group
• 1 ? signs group
• Eligible for chest radiography but did not have
  one ? no-radiograph group

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Material and Methods

• Pneumonia was defined as radiology findings of
  consolidation
• or infiltrates reported in definite terms by the
  report of an attending
• pediatric radiologist.
• Any findings labeled as less than definite (eg.
  atelectasis
• versus infiltrate, equivocal pneumonia, or
  possible
• pneumonia were considered equivocal pneumonia.
• ?negative chest radiogrphs.
• A negative chest radiograph as defined as a
  radiologists
• reading of negative or normal
• Pneumonias detected on empiric chest radiographs
  (ie, in the
• no-signs group) are termed occult pneumonias
• Pneumonias detected in the signs group are termed
  
• nonoccult pneumonias)

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RESULTS

• For the study period
• 3549 patients aged 5 y/o or younger with a triage
  temperature
• of 39.0C or greater
• 389 (11) had a WBC count of 20000 cells/mm3 or
  greater
• 111 patients was excluded for immunodeficiency,
  other infection source than pneumonia, chronic
  lung dz
• 278 patients constitutes the study group, all
  considered eligible for chest radiography.
• All patients with a discharge diagnosis of
  pneumonia underwent chest radiography.
• Questionnaires were completed for 100 of the
  eligible patients.

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RESULTS

• 93 of forms were complete by physicians
  concurrent with pt care, 7 were completed later
  by telephone interview, clinician review of
  medical records , or both

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RESULTS
16
RESULTS
17
RESULTS
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RESULTS

• In the study group
• 63 were febrile 1 day
• 78 2 days
• 88 3 days
• Among patients with pneumonia
• 36 were febrile 1 day
• 57 2 days
• 71 3 days
• Occult pneumonia patients
• 45 were febrile 1 day
• Pneumonia pts in signs group
• 25 were febrile 1 day

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RESULTS
20
RESULTS

• 275 of the 278 pts obtained blood cultures, 6.5
  bacteremia
• WBC 20000-24900 5.0, 25000-29900 8.2,
  WBC3000010.5
• All isolates were S pneumoniae.
• No difference in the rates of bacteremia among
  patients with and without pneumonia
• 3 of 38 pts with occult pneumonia were baceremic
• 53 of 70 pneumonia patients (76)?single
  infiltrates 12 with round pneumonias, 11 with
  more than 1 infiltrate, 6 with lobar
  consolidation
• 29 of 38 (76) occult pneumonia patients with
  single infiltrates, 4 (10) had 2 or more
  infiltrates, and 5 (13) had evidence of lobar
  pneumonia.

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DISCUSSION

• The prevalence of occult pneumonia in patients
  with high fever and leukocytosis but no
  respiratory findings suggestive of pneumonia was
  26 (95 CI, 19-34)
• The minimum estimate of occult pneumonia n this
  population was 19 (95 CI, 14 to 25)
• No individual sign or constellation of findings
  was a sensitive predictor of pneumonia.
• Signs of respiratory distress (eg. Tachypnea,
  grunting, flaring, retracting )or lower
  respiratory tract signs (eg, rales, rhonchi,
  wheeze, focal decreased breath sounds) had high
  specificity.

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DISCUSSION

• The low sensitivity of respiratory findings
  reflects the large number of occult pneumonias
  detected in this select population.
• The guidelines will remain unchanged after this
  study.
• In practice, a chest radiograph may not be
  necessary to diagnose pneumonia, and we are not
  recommending chest radiography in patients in
  whom a clinical diagnosis can be made.

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DISCUSSION

• Limitations of this study
• 1. patients were identified by WBC count, but
  the indications for obtaining( or not obtaining)
  a CVC were not studied
• 2. questionnaires were completed by physicians
  at many levels of training, and the questionnaire
  did not record whether the patient had multiple
  examiners. (56 Residents , 17 fellows, 27
  attendings)
• 3. the prevalence of pneumonia may have been
  underestimatd by considering all the patients
  with equivocal pneumonias and those who did not
  have a radiograph as no-pneumonia patients
• 4. the radiologists were not aware of the
  guidelines or the study, but they were not
  blinded to the information available on the
  radiology requisition, which influences their
  interpretations.

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Conclusion

• Chest radiography should be performed in young,
  febrile children with leukocytosis and no other
  treatable source of infection.
• Administering empiric antibiotics to children
  with leukocytosis should be done only after a
  consideration of what foci of infection may be
  missed on examination alone.
• For febrile infants aged 3 months or less,
  without leukocytosis or clinical evidence of
  upper or lower respiratory tract infection, a
  chest radiograph should not be obtained.