Hypotonic-hyporesponsive episode

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Hypotonic-hyporesponsive episode (HHE)
Symptoms Hypotonia, hyporesponsiveness, pallor, cyanosis. [1] [2]
Usual onset1 minute to 48 hours post-vaccination. [1]
Duration1 minute to 14 days (median 10 hours). [1]
Causes Vaccination, most commonly pertussis vaccine. [1]
Diagnostic method Based on symptoms. [1] [3]
Differential diagnosis Vasovagal syncope, seizure
PreventionThose who experience an HHE after pertussis vaccination may avoid further pertussis vaccines. [1] [4]
TreatmentUsually resolves on its own, management involves checking the airway, breathing, and circulation, and hospitalization for observation and to rule out other conditions. [5] [1] [6]
DeathsNone reported

A hypotonic-hyporesponsive episode (HHE) is defined as sudden onset of poor muscle tone, reduced consciousness, and pale or bluish skin occurring within 48 hours after vaccination, most commonly pertussis vaccination. [2] An HHE is estimated to occur after 1 in 4,762 to 1 in 1,408 doses of whole cell pertussis vaccine, and after 1 in 14,286 to 1 in 2,778 doses of acellular pertussis vaccine. [3]

References

  1. 1 2 3 4 5 6 7 "Hypotonic, hyporesponsive episode (HHE)" (PDF). 7 January 2006. Retrieved 2018-01-24.[ permanent dead link ]
  2. 1 2 Duvernoy, Tracy S.; Braun, M. Miles (October 2000). "Hypotonic–Hyporesponsive Episodes Reported to the Vaccine Adverse Event Reporting System (VAERS), 1996–1998" . Pediatrics. 106 (4): e52. doi:10.1542/peds.106.4.e52. PMID   11015547. S2CID   12743062 . Retrieved 2018-01-22.
  3. 1 2 Bonhoeffer, Jan (2007). "Hypotonic-hyporesponsive episode (HHE) as an adverse event following immunization in early childhood: Case definition and guidelines for data collection, analysis, and presentation". Vaccine. 25 (31): 5875–5881. doi:10.1016/j.vaccine.2007.04.061. PMID   17537554 . Retrieved 2018-02-01.
  4. ↑ "Chapter 16: Pertussis". CDC. Retrieved 2018-01-24.
  5. ↑ "Hypotonic-Hyporesponsive Episodes to Immunisation".
  6. ↑ Duvernoy, Tracy S.; Braun, M. Miles (October 2000). "Hypotonic–Hyporesponsive Episodes Reported to the Vaccine Adverse Event Reporting System (VAERS), 1996–1998" . Pediatrics. 106 (4): e52. doi:10.1542/peds.106.4.e52. PMID   11015547. S2CID   12743062 . Retrieved 2018-01-24.
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