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Anaphylaxis 55

• Coagulation testing may reveal hypocoagu- ○ Terbutaline 0.01 mg/kg IM/IV ○ Serum biochemistry analysis
lability ○ Inhaled albuterol 1-2 puffs from metered ○ Coagulation testing
VetBooks.ir Advanced or Confirmatory Testing Chronic Treatment PROGNOSIS & OUTCOME Diseases and Disorders
dose inhaler per 5-10 kg of patient weight
(p. 1122)
• Abdominal ultrasound may reveal a halo sign
around the gallbladder.
tion are the keys for a successful outcome.
• Animals with chronic heartworm disease may May be instituted instead of acute treatment Immediate recognition and prompt interven-
have pulmonary artery or cardiac abnormali- if a patient is showing only mild clinical signs Anaphylaxis can result in death within 1
ties visible on survey thoracic radiographs. and is hemodynamically stable (common). In minute of exposure to the inciting agent in
general, treatment of anaphylaxis is complete severe cases, but with prompt appropriate
TREATMENT within 24-72 hours of presentation. In some treatment, prognosis is good.
animals with severe shock, chronic care is
Treatment Overview focused on treatments of shock sequelae (e.g., PEARLS & CONSIDERATIONS
• Cardiovascular and respiratory support gastrointestinal injury, coagulopathy).
• Antagonize inflammatory mediators • Glucocorticoid therapy to block release of Comments
• Support coagulation secondary mediators: • Anaphylaxis does not always involve a previ-
• Block further release of inflammatory ○ Dexamethasone sodium phosphate ous exposure and sensitization.
mediators. 0.1-0.2 mg/kg IV once • Anaphylaxis should be suspected in patients
• Remove causative agent. ○ Some animals require a short (2-3 day) with unexplained acute cardiovascular and
course of prednisone 0.25-0.5 mg/kg PO respiratory collapse.
Acute General Treatment q 24h • Fluid therapy and epinephrine are the first
Emergency treatment should be instituted • Antihistamine therapy: lines of treatment for severe anaphylaxis.
based on history and physical examination ○ H1-blocker: diphenhydramine 1-2 mg/
and before extensive diagnostic testing in severe kg IM, SQ, PO q 8h for 24-48h Prevention
cases (patients with dyspnea, hemodynamic ○ H2-blocker: famotidine 0.5-1 mg/kg IV, • Administer IV medications slowly.
instability, or depression/coma). Treatment IM, SQ, PO q 12h • Be aware of and use caution with medications
is cardiovascular support with intravenous known to be associated with anaphylaxis.
(IV) fluid therapy and epinephrine or other Nutrition/Diet • For patients with a history of anaphylaxis,
pressor support as necessary. Mild reactions, Avoid dietary triggers. Severe food allergies are pretreatment with antihistamines and glu-
including urticarial alone, require less intensive rare in dogs and cats in contrast to people, for cocorticoids may be useful in blunting the
intervention. whom peanuts and other life-threatening food inflammatory response when re-exposure is
Cardiovascular support: allergies are reported more regularly. unavoidable.
• IV catheter placement, facilitated techniques, • Avoid revaccination of pets with a history
or cut-down procedure may be necessary Drug Interactions of a severe reaction.
• If cardiovascular instability is present, then • Epinephrine, aminophylline, and terbutaline
epinephrine to treat hypotension, broncho- may be arrhythmogenic. Use caution when Technician Tips
constriction, and block release of inflamma- used together. Prompt recognition of anaphylaxis with initia-
tory mediators • Chronic glucocorticoid therapy is contra- tion of treatment is key to a successful outcome.
○ Epinephrine: 0.01-0.02 mg/kg IV (IM indicated in patients receiving nonsteroidal
for less severe cases), or antiinflammatory drug (NSAID) therapy. Client Education
○ Epinephrine 0.02-0.2 mg/kg intratracheal • Be familiar with your pet’s medical history,
administration in intubated patients Possible Complications and alert your veterinarian of medications
○ Vasopressin 0.5-2 U IV bolus repeated • Cardiac arrhythmias your pet has received, previous blood product
up to 3 times as needed in refractory cases • Consumptive coagulopathy transfusions, and previous allergic reactions.
○ Isotonic crystalloids 20-30 mL/kg IV bolus, • Organ dysfunction • A pediatric EpiPen may be prescribed for
repeated as required after reassessment animals with prior life-threatening reactions.
○ Fresh-frozen plasma used to treat coagu- Recommended Monitoring
lopathy can also provide intravascular • For mild cases (skin reaction only), monitor- SUGGESTED READING
volume support ing at home for recurrence Shmuel DL, et al: Anaphylaxis in dogs and cats. J
Establish airway patency: • For severe cases Vet Emerg Crit Care 23:377-394. 2013.
• With upper airway obstruction or apnea due ○ Frequent monitoring should be continued
to severe laryngeal edema: for 24-48 hours after reaction. AUTHOR: Gareth J. Buckley, MA, VetMB, DACVECC
○ Endotracheal intubation ○ Heart rate, respiratory rate, respiratory EDITOR: Benjamin M. Brainard, VMD, DACVAA,
DACVECC
○ Tracheostomy (p. 1166) effort, pulse rate, pulse quality, mentation,
• Oxygen therapy if evidence of hypoxemia mucous membrane color, capillary refill
(p. 1146) time, temperature, urine output
• Bronchodilation if bronchospasm persists ○ Blood pressure
despite epinephrine administration ○ Electrocardiogram
○ Aminophylline: dog: 5-10 mg/kg IM or ○ Pulse oximetry or arterial blood gases
slow IV; cat: 5 mg/kg IM or slow IV ○ Packed cell volume and total solids

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