Gettysburg Medical News
 The Clinical View
 by P.E. Hoffsten, M.D.
 23 February 2005

WHAT IS ANAPHYLAXIS?

            One of the most dangerous encounters a healthcare professional experiences is to be called for an anaphylactic reaction.  A lady recently came to the clinic and inquired about an anaphylactic reaction because she heard that her sister had one.  I have been fortunate to not have encountered this problem for many years, although I can remember the story below vividly from the time when I was a medical student.

            The lady had come to the ER complaining of having a sore throat.  She was a schoolteacher in her 20’s and indicated that she did not have a previous problems with streptococcus.  But on this particular occasion, it appeared very likely that she had a streptococcal sore throat.  The intern in the emergency room examined the patient and showed me the severe infection the patient had in her throat.  He then indicated that he was going give her a shot of Penicillin to treat the streptococcal infection.  This was done and the lady went out of the emergency room to catch a cab and go home.  The cab driver related that he had only gone about a half of a block away from the hospital when the patient complained of difficulty breathing.  The cab driver recalls hearing her wheezing.  He turned to come back to the hospital and bring her back to the emergency room.  By the time that she had arrived, she had collapsed and in spite of resuscitative efforts made, she died.  This is an example of a classic anaphylactic reaction to a medication, the Penicillin shot in this case.

            An anaphylactic reaction occurs when the person is allergic to a certain chemical.  The chemical can be a medicine, such as penicillin, or it can be the poison in a bee sting, or it can be the components of shrimp in people that have seafood allergies.  Patients prone to anaphylaxis develop antibodies to these various chemicals.  The allergies are very selective.  A person may be very allergic to bee stings but have no allergies to medications or shrimp or strawberries.  When the person experiences the chemical to which they are allergic, the patient’s antibodies react with the chemical to which they are allergic. A series of cells are activated in the body called mast cells.  These cells release histamine which lower the person’s blood pressure dramatically quickly.  Histamine also causes the airways in the lungs to constrict so that airflow is blocked and the person has a sudden asthmatic attack.  In the case of the patient mentioned above, the airflow abnormality was so serious causing her blood pressure to drops so low that she died.

            The lady who had asked what an anaphylactic reaction was, wondered if she might be susceptible to an anaphylactic reaction because her sister had one.  In fact, hereditary carries very little predictive value regarding family members getting anaphylactic reactions if their siblings had one.

            Once a person has had an anaphylactic reaction and the chemical to which they have had a reaction is identified, repeat reactions present a severe danger.  I once took care of a lady who was allergic to pimentos.  She had to be extremely careful about eating salads or other preparations in restaurants where pimentos were added and she didn’t know it.  Twice she had had near fatal reactions from eating pimentos.  She learned to care an “EpiPen” with her for when emergencies occurred.  The best treatment for anaphylactic reaction is an injection of epinephrine.  Patients are advised to carry the pen with them all of the time as a kit strapped to their belt or for a lady to carry it in her purse.  When an anaphylactic reaction occurs, they are often as rapid as described above.

            Anaphylactic reactions are not always as severe as described above.  Sometimes individuals will simply develop slight asthmatic attacks or a swelling of their tongue and throat.  Often times these symptoms can be effectively treated with Benadryl as an over-the-counter antihistamine.

            In some individuals who have had severe reactions, a desensitation is carried out.  With this procedure, very tiny amounts of the problem chemical is administered to the person in slightly increasing doses over a period of months.  This technique develops a different type of immune reaction than the antibody that causes anaphylaxis and the anaphylactic reaction is stopped.

            Obviously, the very best defense against an anaphylactic reaction is to never to take a drug or a chemical to which the person is allergic.  The healthcare professionals at your local clinics are distinctly and always aware of potential for allergic reactions with medications that are used.  Penicillin and sulfa drugs are the two most dangerous and troublesome medications.  Unfortunately, they are also two of our most commonly used medications and great care must be exercised to avoid allergic reactions.