Haemophilus influenzae infection
Haemophilus influenzae infection: Excerpt from Handbook of Diseases
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.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Handbook of Diseases
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2003
ISBN: 1-58255-266-5
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