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Afebrile Pneumonia Syndrome Workup

  • Author: Dagnachew (Dagne) Assefa, MD, FAAP, FCCP; Chief Editor: Michael R Bye, MD  more...
Updated: Oct 13, 2015

Approach Considerations

Knowledge of the likely pathogens in afebrile pneumonia syndrome (APS) can guide the selection of laboratory studies. However, detection of one of these organisms is not conclusive evidence of causation because all of them may colonize infants without producing disease.


Complete Blood Count

In patients with APS, the CBC may reveal a mild eosinophilia, with or without mild leukocytosis.



Serum immunoglobulin levels are typically moderately elevated.


Tests for Chlamydia trachomatis

Tissue culture isolation of the organism from nasopharyngeal specimens is the most useful test for C trachomatis. If conjunctivitis is present, conjunctival specimens are also helpful. Nonculture techniques include direct fluorescent antibody (DFA) tests and enzyme-linked immunoassays (EIAs).

Polymerase chain reaction (PCR), ligase chain reaction (LCR), and other nucleic acid probe techniques are routinely becoming more available.[10, 11]

Serology is useful but takes longer than the above-named tests.


Tests for Cytomegalovirus

Cell culture is the definitive test for CMV. Urine, respiratory secretions, or blood buffy coat (including the shell-vial centrifugation technique) may be used. Polymerase chain reaction and nucleic acid hybridization are becoming more readily available.[12] Serology is often useful, although it takes longer than more direct methods.


Tests for Ureaplasma urealyticum

U urealyticum can be cultured from respiratory secretions. PCR and serology are not routinely available.


Tests for Other Pathogens

RSV, parainfluenza virus, and adenovirus can be cultured from respiratory secretions, although DFA, EIA, and polymerase chain reaction (PCR) are more rapid and more readily available. P jiroveci is diagnosed using DFA on secretions or biopsy material from the lungs.


Chest Radiography

Chest radiographs may reveal the following[13] :

  • Air trapping
  • Bronchial wall thickening
  • Diffuse interstitial infiltrates (which may be out of proportion to the clinical condition, especially in infants with C trachomatis infection)
  • Atelectasis
  • Reticulonodular or miliary pattern (rare)

Go to Imaging in Pediatric Pneumonia for more complete information on this topic.


Pulmonary Function Testing

Results of infant pulmonary function testing (when available) are frequently abnormal in both the acute phase of infection and the long term.


Bronchoalveolar Lavage

Bronchoalveolar lavage with or without transbronchial biopsy may be used to collect specimens for diagnosis if the clinical severity warrants.


Histologic Findings

Special stains of biopsy material may reveal evidence of particular etiologies. More commonly, direct or indirect fluorescent antibody staining helps identify viral antigens in respiratory secretions (RSV, adenovirus, and parainfluenza).

Contributor Information and Disclosures

Dagnachew (Dagne) Assefa, MD, FAAP, FCCP Pediatric Pulmonologist, Pediatric Lung Care, Bon Secours

Dagnachew (Dagne) Assefa, MD, FAAP, FCCP is a member of the following medical societies: American Academy of Pediatrics, American Academy of Sleep Medicine, American College of Chest Physicians, American Thoracic Society, European Respiratory Society

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Chief Editor

Michael R Bye, MD Professor of Clinical Pediatrics, State University of New York at Buffalo School of Medicine; Attending Physician, Pediatric Pulmonary Division, Women's and Children's Hospital of Buffalo

Michael R Bye, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, American Thoracic Society

Disclosure: Nothing to disclose.

Additional Contributors

Susanna A McColley, MD Professor of Pediatrics, Northwestern University, The Feinberg School of Medicine; Director of Cystic Fibrosis Center, Head, Division of Pulmonary Medicine, Children's Memorial Medical Center of Chicago

Susanna A McColley, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, American Sleep Disorders Association, American Thoracic Society

Disclosure: Received honoraria from Genentech for speaking and teaching; Received honoraria from Genentech for consulting; Partner received consulting fee from Boston Scientific for consulting; Received honoraria from Gilead for speaking and teaching; Received consulting fee from Caremark for consulting; Received honoraria from Vertex Pharmaceuticals for speaking and teaching.


Heidi Connolly, MD Associate Professor of Pediatrics and Psychiatry, University of Rochester School of Medicine and Dentistry; Director, Pediatric Sleep Medicine Services, Strong Sleep Disorders Center

Heidi Connolly, MD is a member of the following medical societies: American Academy of Pediatrics, American Thoracic Society, and Society of Critical Care Medicine

Disclosure: Nothing to disclose.

Judith R Grisi, PA-C Physician Assistant, Monmouth Ocean Pulmonary Medicine, CentraState Medical Center

Disclosure: Nothing to disclose.

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