Haemophilus influenzae infection

Haemophilus influenzae is a common cause of epiglottiditis, laryngotracheobronchitis, pneumonia, bronchiolitis, otitis media, and meningitis. Less commonly, it causes bacterial endocarditis, conjunctivitis, facial cellulitis, septic arthritis, and osteomyelitis.

H. influenzae pneumonia is an increasingly common nosocomial infection. It’s the second-leading cause of bacterial pneumonia deaths in children. Breast-feeding during the first 6 months provides passive protection of some infants. It infects about one-half of all children before age 1 and virtually all children by age 3, although a new vaccine given at ages 2, 4, and 6 months has reduced this number.

Causes

A small, gram-negative, pleomorphic aerobic bacillus, H. influenzae causes diseases in many organ systems but most frequently attacks the respiratory system. In exudates, this organism predominantly resembles a coccobacillus. It’s transmitted by airborne droplets or direct contact with secretions or fomites.

Signs and symptoms

H. influenzae provokes a characteristic tissue response — acute suppurative inflammation.

When H. influenzae infects the larynx, trachea, and bronchial tree, it leads to mucosal edema and thick exudate; when it invades the lungs, it leads to bronchopneumonia.

In the pharynx, H. influenzae usually produces no remarkable changes, except when it causes epiglottiditis, which generally affects both the laryngeal and the pharyngeal surfaces.

The pharyngeal mucosa may be reddened, rarely with soft yellow exudate. More commonly, it appears normal or shows only slight diffuse redness, even while severe pain makes swallowing difficult or impossible. These infections typically cause high fever and generalized malaise.

Diagnosis

Isolation of the organism, usually with a culture, confirms H. influenzae infection. Other laboratory findings include:

❑ polymorphonuclear leukocytosis (15,000 to 30,000/µl)

❑ leukopenia (2,000 to 3,000/µl) in young children with severe infection

❑ H. influenzae bacteremia, found frequently in patients with meningitis.

Treatment

H. influenzae infections usually respond to a 2-week course of ampicillin, but 30% of strains are resistant. Ceftriaxone, cefotaxime, or chloramphenicol is used concurrently until sensitivities are identified.

Special considerations

❑ Maintain adequate respiratory function through proper positioning, humidification in children, and suctioning, as needed.

❑ Monitor the rate and type of respirations.

❑ Watch for signs of cyanosis and dyspnea, which necessitate intubation or a tracheotomy.

❑ For home treatment, suggest that the patient use a room humidifier or breathe moist air from a shower or bath, as necessary.

❑ Check the patient’s history for drug allergies before giving antibiotics.

Clinical tip  Monitor the complete blood count for signs of bone marrow depression when therapy includes chloramphenicol.

❑ Monitor intake (including I.V. infusions) and output. Watch for signs of dehydration, such as decreased skin turgor, parched lips, concentrated urine, decreased urine output, and increased pulse rate.

❑ Take preventive measures, such as giving the H. influenzae vaccine to children ages 2 (or younger) to 6, maintaining respiratory isolation, using proper hand-washing technique, properly disposing of respiratory secretions, placing soiled tissues in a plastic bag, and decontaminating all equipment.

Book Source Details

• Book Title: Handbook of Diseases
• Author(s): Springhouse
• Year of Publication: 2003
• Copyright Details: Handbook of Diseases, Copyright © 2003 Lippincott Williams & Wilkins.

Other Book Chapters Related to Infection

Read excerpts from these other book chapters related to Infection:

Copyright Details: Handbook of Diseases, Copyright © 2008 Williams & Wilkins.

More About Causes of Infection

• Back to symptom: Infection: Introduction (review 311 causes)
• Next Book Extract About Infection: Human immunodeficiency virus infection (Handbook of Diseases)
• All Book Extracts: All Online Book Extracts for Infection

More About This Book: Title: Handbook of Diseases Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2003 ISBN: 1-58255-266-5

 » Next page: Human immunodeficiency virus infection (Handbook of Diseases)

Rate This Website

What do you think about the features of this website? Take our user survey and have your say:

Website User Survey

Medical Tools & Articles:

Next articles:

• Human immunodeficiency virus infection (Handbook of Diseases)
• Respiratory syncytial virus infection (Handbook of Diseases)
• Vancomycin-resistant enterococcus (Handbook of Diseases)
• Recurrent Infection (The Diagnostic Approach to Symptoms and Signs in Pediatrics)
• Medications causing Infection

Tools & Services:

• Bookmark this page
• Take a survey relating to Infection
• Symptom Search
• Symptom Checker
• Medical Dictionary
• Give your feedback

Medical Articles:

• Disease & Treatments Search
• Misdiagnosis Center
• Full list of interesting articles

Forums & Message Boards

• Ask or answer a question at the Boards:
• I cannot get a diagnosis. Please help.
• Tell us your medical story.
• Share your misdiagnosis story.
• What is the best treatment for my condition?
• See all the Boards.

Enter your search terms Submit search form
Search The Web Search wrongdiagnosis.com

Common Health Mistakes

Symptom
Checker

Search Specialists by State and City