Page 11 - Journal of Special Operations Medicine - Winter 2014

Management of Anaphylaxis
in an Austere or Operational Environment

B. Craig Ellis, MBChB, FACEM; Simon G. A. Brown, MBBS, PhD, FACEM

ABSTRACT
We present a case report of a Special Operations Sol- injection of 0.5mg epinephrine. His symptoms of light-
dier who developed anaphylaxis as a consequence of a headedness and vomiting resolved. However, the rash
bee sting, resulting in compromise of the operation. We did not improve. His radial pulse returned and a rate of
review the current literature as it relates to the patho- 122/min was recorded. After approximately 25 minutes,
physiology of the disease process, its diagnosis, and its the light-headedness returned and he was noted again to
management. An evidence-based field treatment algo- have an absent radial pulse. Additional epinephrine was
rithm is suggested. administered via IM injection.

Keywords: anaphylaxis, anaphylactic shock, epinephrine, At this stage, the patrol commander made a decision to
epinephrine infusion, review, remote, austere abandon the operation and called for a medical evacua-
tion by rotary wing. The patient remained symptomatic
and received additional IM epinephrine and 1L normal
saline from the helicopter medical team. On arrival at a
Introduction
Tier 3 facility, he was still tachycardic and hypotensive
Anaphylaxis is an unpredictable emergency that requires and had an altered conscious state. He was assessed by
a prompt response. It is typically precipitous, occurs in a medical officer (specialist emergency physician) and
previously fit and healthy people, and can compromise received 2L normal saline and an epinephrine infusion
a military operation or civilian expedition. It usually with resolution of his symptoms. The infusion was dis-
responds to very simple treatment with intramuscular continued after 45 minutes.
epinephrine, but multiple doses may be required, and on
rare occasions, further measures may also be required,
including high-volume fluid resuscitation, additional Discussion
vasopressors, and advanced airway management. We
examine an operational case and provide an updated Pathophysiology and Diagnosis
overview of the pathophysiology and optimal field Anaphylaxis is a generalized hypersensitivity reaction,
management. characterized by vasodilation (“flare” or erythema, dis-
tributive shock), extravasation of fluid (angioedema,
hypovolemic shock), and smooth muscle contraction
Case Presentation
(bronchospasm, cramping visceral and/or uterine pain).
A 34-year-old, deployed Special Operator with no prior Impaired cardiac function may also occur, although the
history of anaphylaxis disturbed a wild colony of bees contribution of this effect is difficult to define because
and was stung multiple times. of the multiple other pathophysiological changes caus-
ing hypotension. Clinically, anaphylaxis is defined as a
Within 4 minutes, he experienced an intensely itchy rash skin rash accompanied by the involvement of at least
over his trunk and lower limbs, and he felt very light- one of the cardiovascular (e.g., low blood pressure,
headed and vomited several times. He was assessed by signs of poor perfusion, or collapse), respiratory (e.g.,
the non–vocationally trained team medic, who diagnosed stridor or bronchospasm), or gastrointestinal systems
anaphylaxis. His heart rate was described as “fast,” he (e.g., abdominal pain, vomiting, or diarrhea) following
had no palpable radial pulse, and he had a Glasgow exposure to an antigen. A consensus clinical definition
Coma Scale score of 13 and an extensive urticarial rash. has been developed that can be used for both research
The team medic administered an intramuscular (IM) and clinical application (Table 1). 1

1