Anaphylactic Shock

Anaphylactic reactions are acute, severe, potentially fatal responses to oral or parenteral administration of medication. Although adverse drug reactions are not uncommon, most are mild and are of short duration. Anaphylaxis, however, requires immediate recognition and prompt, effective action since it can quickly become lethal.

The most common presenting signs for anaphylactic shock are cutaneous or cardiorespiratory in nature. Prevalent symptoms include:

• Skin manifestations: diffuse rapidly spreading urticaria, a sensation of warmth, and rapidly increasing swelling of the face and tongue
• Respiratory manifestations: tightness in the chest, wheezing, coughing, or rales
• Cardiopulmonary manifestations: deepening hypotension, and dizziness and/or syncope

Bronchospasm can lead to anoxia, which in turn potentiates vascular collapse. Cardiac arrest and death can occur within 15 minutes or less.

The list of drugs and substances that can cause anaphylactic shock is virtually endless. The following compilation from Principles and Practice of Emergency Medicine (W.B. Sanders Co., 1986) is only a partial listing of the most common substances.

• Antimicrobials
  • Penicillins
  • Cephalosporins
  • Sulfonamides
  • Aminoglycosides
  • Tetracyclines
  • Chloramphenicol
  • Nitrofurantoin (Furadantin)
  • Amphotericin B
  • Para-Amino Salicylic Acid
  
  
• Analgesics
  • Salicylates
  • Aminopyrine
  • Phenylbutazone (Butazolidin)
  • Indomethacin (Indocin)
  • Tolmetin (Tolectin)
  • Pentazocine (Talwin)
  
  
• Other Drugs
  • Heparin
  • Meprobamate
  • Thiamine
  • Folic Acid
  • Sulfobromophthalein (BSP)
  • Sodium Dehydrocholate (Decholin)
  
  
• Enzymes
  • Trypsin
  • Chymotrypsin
  • Penicillinase (Neutrapen)
  
  
• Other Agents
  • Hymenoptera Sting (bee, wasp, hornet, fire ant).
  • Snake venom
  • Foods (shellfish, egg albumin, nuts)
  
  
• Iodinated Contrast Media
  
  
• Antilymphocyte Globulin
  
  
• Heterologous Antisera
  
  
• Allergenic Extracts
  
  
• Vaccines

A negative history of adverse reaction does not preclude anaphylactoid reactions. Symptoms can begin as early as 2 minutes or as late as 60 minutes after administration or ingestion. Response to effective treatment can be rapid or can take days.

Emergency Measures

Since laryngeal edema and vascular collapse are the preeminently most dangerous manifestations, they require the most urgent attention.

1. Administer aqueous epinephrine, 1:1000, 0.3 to 0.5 ml subcutaneously. (For children, give 0.01 ml/kg). In profound hypotension, epinephrine can be diluted in 10 ml of saline and given intravenously, slowly. If epinephere 1:10,000 is available, it is intended for intravenous injection and should not be diluted. Given intravenously, epinephrine can precipitate cardiac arrhythmias, which might require additional treatment.
2. Establish airway. Start oxygen. Do not wait for color to improve. Assist with ventilation. The larynx may be too edematous. If in doubt, perform immediate emergency tracheostomy. If a tracheostomy set is not instantly available, use a No.14 or No.16 needle between the tracheal rings until one arrives.
3. Start IV with saline (if necessary, do a “cut down”).
4. If bronchospasm persists (despite epinephrine administration), give aminophylline, 5mg/kg IV slowly. If patient is wheezing, consider nebulized Isuprel (or other bronchodilator).
5. For adults, give Benadryl 25-50 mg IV stat and repeat every 4 to 6 hours.
6. For adults, give Solu-Cortef 100 to 500 mg IV every 6 hours (corticosteroids, though very important, will not act rapidly enough to reverse acute anaphylaxis).
7. Prolonged hypotension, like shock, can respond to IV saline, plasma, or colloids (Dextran). If it does not, consider using 400 mg of Dopamine in 500 ml of saline and titrate, carefully. Remember that hypotension can lead to metabolic acidosis, which will require intravenous sodium bicarbonate.
8. As in all potentially fatal emergencies, the patient should be hooked up to a cardiac and pulse oximeter monitor as quickly as possible and then rapidly transferred to an intensive care unit.

The Doctors Company Recommendations

The Doctors Company strongly recommends that all physicians administering drugs, vaccines, diagnostic materials, or any other potentially antigenic substances have on hand the emergency drugs and resuscitating equipment necessary to tide them over until trained help arrives. All physicians should be familiar with the American Heart Association resuscitation protocols.

J3214 6/98

Updated: June 1998
Originally published: April 1990