Haemophilus influenza type a (Hia)
From Guide to YKHC Medical Practices
Background:
- gram-negative bacteria that most commonly causes meningitis, pneumonia with bacteremia, septic arthritis, and cellulitis (often rapidly progressing) with bacteremia.
Epidemiology:
- from 2014-2018, 107 cases were reported with 91% of the reported cases in the state of Alaska in Alaska Natives and 69% from the YK Delta region
- median age: 1.1 yrs
- incidence for Alaska Native children <2y/o living in the YK Delta region: 781/100,000 (similar to Hib prior to introduction of the vaccine in 1991)
Diagnosis:
- must have high clinical suspicion
- with high fevers (>104) without a source
- rapidly progressing cellulitis and/or ill appearing (give Ceftriaxone empirically in addition to staph coverage with Vancomycin)
- obtain blood, wound, or CSF culture
- YKHC lab can culture H. flu, but does not report serotype (A through F)
- (all invasive H. flu isolates are sent to AIP for serotyping)
- Can send culture fluids to the state for PCR testing (this is usually done if the culture is positive for H. flu OR negative due to pretreatment OR negative and highly suspicious for Hia)
Management:
- all cases from 2014-2018 were susceptible to Amoxicillin
- Patients are often given Ceftriaxone empirically until cultures return, then narrow as appropriate.
- If susceptible to Amoxicillin and not meningitis, one dose of Ceftriaxone is sufficient to clear the infection (no need for chemoprophylaxis upon at end of therapy) followed by Amoxicillin oral therapy
Critical Times for Affected Patients:
- 25% of children <10y/o died or had severe neurologic outcomes
- if high suspicion for meningitis, do not delay antibiotics for lumbar puncture
- if high suspicion for Hia with cellulitis, add Ceftriaxone
Chemoprophylaxis Recommended:
- similar to recommendations for Hib cases
- household contacts of a person with invasive Hia when at least one household member is <4y/o or an immuno-compromised child
- preschool and child care center contacts when 2 or more cases of Hia have occurred within 60 days
- index pt is <2y/o or has susceptible household member and not treated with cefotaxime or ceftriaxone
- NOT recommended for pregnant women
- rifampin 20mg/kg (max dose 600mg) po daily x4 days (for infants <1 month old, some recommend lowering to 10 mg/kg.)
- start as soon as possible, but give even a week after index patient hospitalization
- NOTE to Pediatricians: see the HIA folder in the Peds folder for a sample Hia prophylaxis letter to families(HiA PPX letter)
Resources/References
- Invasive disease due to Haemophilus influenza type A in children in Canada’s north: A priority for prevention
- Plumb et al. Invasive Haemophilus influenzae Serotype a Infection in Children: Clinical Description of an Emerging Pathogen — Alaska, 2002–2014. Pediatr Infect Dis J. 2018 April ; 37(4): 298–303. doi:10.1097/INF.0000000000001764
- Haemophilus influenzae Invasive Disease. Alaska Department of Health and Social Services (ADHSS) Resource (2018).
- ADHSS Haemophilus Influenzae Epi Bulletins
