RT Book, Section
A1 Moss, Jonathan
A1 Mertes, Paul-Michel
A2 Hall, Jesse B.
A2 Schmidt, Gregory A.
A2 Wood, Lawrence D.H.
SR Print(0)
ID 2281763
T1 Chapter 106. Anaphylactic and Anaphylactoid Reactions
T2 Principles of Critical Care, 3e
YR 2005
FD 2005
PB The McGraw-Hill Companies
PP New York, NY
SN 9780071416405
LK accessmedicine.mhmedical.com/content.aspx?aid=2281763
RD 2021/04/16
AB Mast  cells  or  basophils  release  mediators  of  anaphylactic  and  anaphylactoid  reactions  as  a  result  of  direct  drug  actions  or  interaction  of  antigen  with  mast  cell  or  basophil  immunoglobin  E.Agents  that  commonly  cause  hypersensitivity  reactions  are  antibiotics,  blood  products,  radiocontrast  media,  muscle  relaxants,  colloids,  preservatives,  protamine,  and  latex.Histamine,  eosinophilic  chemotactic  factor  of  anaphylaxis,  slow-reacting  substance  of  anaphylaxis,  platelet-activating  factor,  prostaglandins,  and  kinins  are  the  six  major  pharmacologic  mediators  known  to  be  released  in  anaphylactic  and  anaphylactoid  reactions.Symptoms  caused  by  these  mediators  are  usually  immediate  but  may  be  delayed  by  2  to  15  minutes  or,  in  rare  cases,  by  as  long  as  2.5  hours  after  the  parenteral  injection  of  antigen.Because  this  reaction  includes  vasodilation  and  translocation  of  fluid  from  capillaries  and  postcapillary  venules  (resulting  in  loss  of  fluid  and  colloid  from  intravascular  spaces),  effective  plasma  volume  and  systemic  vascular  resistance  is  decreased,  which  can  lead  to  shock.The  sine  qua  non  of  anaphylaxis  is  severe  cardiovascular  or  respiratory  compromise;  most  conscious  patients  sense  impending  doom  before  the  clinical  event  occurs.Tryptase  is  helpful  in  distinguishing  between  anaphylactic  and  anaphylactoid  reactions.Although  various  drugs  are  used  to  treat  anaphylactic  and  anaphylactoid  reactions,  discontinuation  of  the  offending  drug,  maintenance  of  the  airway,  administration  of  oxygen,  blood  volume  expansion,  and  administration  of  titrated  doses  of  epinephrine  (very  large  doses  may  be  needed)  are  the  mainstays  of  therapy.Anaphylactic  and  anaphylactoid  reactions  are  acute,  potentially  fatal  events,  but  their  morbidity  and  mortality  rates  can  be  decreased  by  preparation,  drills  such  as  those  done  for  cardiopulmonary  resuscitation,  and  prompt  recognition  and  aggressive  treatment.