Pediatric Haemophilus Influenzae Infection Workup

  • Author: Mobeen H Rathore, MD, CPE, FAAP, FIDSA; Chief Editor: Russell W Steele, MD   more...
 
Updated: May 24, 2012
 

Laboratory Studies

  • Culture
    • This is the most important laboratory study in the context of suspected Haemophilus influenzae disease.
    • In children, the organism causing these infections is blood borne: hence, blood culturing is important in all cases.
    • H influenzae can be cultured from samples of CSF, synovial fluid, pleural and pericardial fluid, and leading-edge aspirates of cellulitis.
  • Antigen detection
    • Numerous methods are available for identifying the H influenzae type b (Hib) PRP capsular polysaccharide antigen in clinical specimens.
    • Suitable specimens for study may be obtained from urine and CSF. These are particularly helpful in the patient who has been pretreated with antimicrobial therapy.
    • Antigen detection has little use in clinical practice, except in the situation mentioned above; most clinical laboratories do not offer this test.
  • Biochemical identification
    • Biochemical identification of H influenzae is based on the demonstration that growth in rich media (blood agar) is dependent on supplements, namely, factors X and V. Factor X is a heat-stable iron-containing protoporphyrin (hemin) that is essential for the function of enzymes in the electron-transport chain in aerobic metabolism. Factor V is the heat-labile coenzyme nicotinamide adenine dinucleotide (NAD).
    • Although both factors are present in erythrocytes, factor V must be released from the cell to sustain its growth; hence, standard blood agar is an unsatisfactory media for the growth of H influenzae. The lysis of RBC releases factor V, providing an exogenous source such as that in chocolate agar.
    • The metabolic requirement of factors X and V for growth remains the major basis for the laboratory identification of H influenzae. The growth requirements of H influenzae are fastidious, and the organism rapidly loses viability; therefore, clinical specimens must be handled expeditiously.
    • After overnight incubation, gray colonies appear; these have a diameter of 0.5-0.8 mm and are rough or granular. Encapsulated strains typically produce larger mucoid or glistening colonies.
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Imaging Studies

  • Chest or lateral neck radiography, brain CT echocardiography, and technetium bone scanning may be appropriate.
  • Imaging studies depend on the clinical syndrome.
    • In epiglottis, lateral neck radiography can be helpful if the clinical presentation is subtle, but the study should be performed cautiously, without undue delays, and a physician experienced in airway management should be present.
    • Approximately 50% of patients with pneumonia have evidence of pleural involvement at initial radiographic examination. Pneumonia can have a segmental, subsegmental, interstitial, or lobar pattern.
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Procedures

  • Procedures depend on the clinical circumstances. Necessary procedures may include the following:
    • Lumbar puncture
    • Arthrocentesis
    • Pericardiocentesis
    • Endotracheal intubation or tracheostomy
    • Subdural tap
    • Leading-edge aspirate
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Histologic Findings

  • H influenzae is a small gram-negative coccobacillus that may have considerable microscopic pleomorphism, which necessitates the careful and cautious interpretation of Gram stains of clinical specimens .
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Contributor Information and Disclosures
Author

Mobeen H Rathore, MD, CPE, FAAP, FIDSA  Chief of Division of Pediatric Infectious Diseases/Immunology, Associate Chairman of Department of Pediatrics, University of Florida College of Medicine at Jacksonville; Hospital Epidemiologist and Section Chief of Infectious Disease and Immunology, Wolfson Children's Hospital; Director of University of Florida Center for HIV/AIDS Research, Education and Service (UF CARES)

Mobeen H Rathore, MD, CPE, FAAP, FIDSA is a member of the following medical societies: American Academy of Pediatrics, American Society for Microbiology, European Society for Paediatric Infectious Diseases, Florida Medical Association, Florida Pediatric Society, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Society for Healthcare Epidemiology of America, Society for Pediatric Research, Southern Medical Association, and Southern Society for Pediatric Research

Disclosure: Nothing to disclose.

Coauthor(s)

Ayesha Mirza, MD  Assistant Professor, Pediatric Infectious Diseases, University of Florida College of Medicine Jacksonville

Ayesha Mirza, MD is a member of the following medical societies: American Academy of Pediatrics, American Society of Tropical Medicine and Hygiene, HIV Medicine Association of America, Infectious Diseases Society of America, and Pediatric Infectious Diseases Society

Disclosure: Nothing to disclose.

Specialty Editor Board

David Jaimovich, MD  Chief Medical Officer, Joint Commission International and Joint Commission Resources

David Jaimovich, MD is a member of the following medical societies: American Academy of Pediatrics

Disclosure: Nothing to disclose.

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.

Mark R Schleiss, MD  American Legion Chair of Pediatrics, Professor of Pediatrics, Division Director, Division of Infectious Diseases and Immunology, Department of Pediatrics, University of Minnesota Medical School

Mark R Schleiss, MD is a member of the following medical societies: American Pediatric Society, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, and Society for Pediatric Research

Disclosure: Nothing to disclose.

Robert W Tolan Jr, MD  Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine

Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility

Disclosure: Novartis Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD  Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine

Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association

Disclosure: Nothing to disclose.

References

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  2. [Best Evidence] CDC. Invasive Haemophilus influenzae type b disease in five young children--Minnesota, 2008. MMWR. January 2009;58:58-60. [Medline]. [Full Text].

  3. Burns IT, Zimmerman RK. Haemophilus influenzae type B disease, vaccines, and care of exposed individuals. J Fam Pract. Sep 2000;49(9 Suppl):S7-13; quiz S14. [Medline].

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  8. [Best Evidence] [Guideline] CDC. Licensure of a Haemophilus influenzae type b (Hib) vaccine (Hiberix) and updated recommnedations for use of Hib vaccine. MMWR. 2009;58:1008-1009. [Medline]. [Full Text].

  9. Dajani AS, Asmar BI, Thirumoorthi MC. Systemic Haemophilus influenzae disease: an overview. J Pediatr. Mar 1979;94(3):355-64. [Medline].

  10. Hamlin J, Senthilnathan S, Bernstein HH. Update on universal childhood immunizations. Curr Opin Pediatr. Aug 2008;20(4):483-9. [Medline].

  11. Lebel MH, Freij BJ, Syrogiannopoulos GA, et al. Dexamethasone therapy for bacterial meningitis. Results of two double-blind, placebo-controlled trials. N Engl J Med. Oct 13 1988;319(15):964-71. [Medline].

  12. Murphy TF, Apicella MA. Nontypable Haemophilus influenzae: a review of clinical aspects, surface antigens, and the human immune response to infection. Rev Infect Dis. Jan-Feb 1987;9(1):1-15. [Medline].

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