Treating Anaphylaxix Essay, Research Paper

Treating Anaphylaxix

Research Paper Paramedic Procedures I – Fall 1996 11/3/96

In the emergency setting, anaphylaxis is a dangerous, life threatening condition

that must be treated in an aggressive and timely fashion. Anaphylaxis is a

condition related to acute allergic reactions. Following the body’s exposure to

the offending allergen, there are common systemic reactions. The most serious

reactions involve the respiratory and cardiovascular systems, but the

gastrointestinal, dermatologic, and genitourinary systems are often involved

causing varied symptoms such as urticaria, flushing, angioedema, bronchospasm,

hypotension, cardiac arrythmias, nausea, intestinal cramps, pruritus, and

finally uterine cramps. (Physician Assistant, 8/94) The above list is by no

means exhaustive, specific symptoms vary from person to person. The same person

suffering from several anaphylactic reactions can also present with differing

symptoms.

Physiologically speaking, the two main effects of the body’s released mediators

(IgE) during an anaphylactic reaction are smooth muscle contraction and

vasodilatation, which cause most of the body’s adverse symptoms. (JAMA,

11/26/82) Since the most life threatening reactions usually involve the

respiratory and cardiovascular systems, that is where emergency treatment is

focused. In the cardiovascular system, a combination of vasodilatation,

increased vascular permeability, tachcycardia, and arrhythmias can lead to

severe hypotension. In the respiratory system, the swelling of tissues along

with bronchospasm and increased mucus production are the main cause of death.

So, if untreated, anaphylaxis can be fatal as a result of the body’s going into

what is essentially shock, while simultaneously (and more importantly) being

deprived of the oxygen needed to sustain life.

As of today there is one universally accepted treatment for acute anaphylaxis.

Epinephrine. Epinephrine is both an alpha and a beta agonist. This makes it

the drug optimally suited to treat anaphylaxis. “Epinephrine will increase

vascular resistance, reduce vascular permeability, produce bronchodilation and

increase cardiac output.” (Emergency, 10/93)

Epinephrine will directly counteract the potentially life threatening aspects of

anaphylaxis. Epinephrine can , and is, used in the both the pre-hospital

environment as well as in definitive care institutions. Epinephrine is widely

administered by ALS providers the world over. The drug is so effective that and

relatively simple to use that “?subcutaneous administration of epinephrine by

EMT-B’s trained in recognition ? of anaphylaxis? is safe.” (Annals of

Emergency Medicine, 6/95)

Following the administration of epinephrine, antihistamines such as

diphenhydramine, hydroxyzine, and promethazine can be administered. These

agents block the harmful effects of histamine, a mediator associated with

allergic reactions, and while not displacing histamine from receptors, they

compete with histamine for receptor cites and therefore block additional

histamine from binding. (JEMS, 4/95)

Patients taking beta adrenergic blocking agents will have limited benefits from

the administration of epinephrine (it being a beta agent), as well potentially

unopposed alpha adrenergic effects that could result in severe hypertension.

(Physician Assistant, 8/94) In such cases norepinepherine and dopamine may be

necessary to treat systemic anaphylaxis. Glucagon which increases cAMP, is a

bronchodilator, and stimulates cardiac output, can be very useful, even in the

presence of beta blockers. (Physician Assistant, 8/94)

Inhaled bronchodilators are useful for the treatment of respiratory

complications associated with anaphylaxis. There is a wide variety of

acceptable agents. Sympathomimetics such as albuterol, and metaproterenol will

relax the smooth muscle in the respiratory tract. Anticholinergic agents such

as ipratropium bromide can also decrease bronchospasm. Aminophylline, a

bronchodilator and diuretic can also increase intracellular cAMP levels, as well

as potentiating catecholamines and stimulating their release; these effects

make it a useful tool in dealing with persistent bronchospasm. (Physician

Assistant, 8/94)

Even though steroids (glucocorticosteroids) have some potentially beneficial

effects for the relief of bronchospasm and hypotension, they are not recommended

for the treatment of acute anaphylactic symptoms due to the fact that it takes

four to six hours for them to be effective. (JAMA, 11/26/82) But, steroids

such as methylprednisolone and hydrocortisone, are useful in shortening the

duration of, and reducing the severity of prolonged anaphylactic reactions, as

well as preventing the recurrence of delayed symptoms. (Physician Assistant,

8/94)

The above agents are all widely used to treat anaphylaxis. But there are

studies and experiments underway that are looking at alternative, or additional

treatments. Naloxone and thyrotropin-releasing hormone (TRH) are both being

looked at in the possible treatment of anaphylaxis as well as traumatic shock.

“Naloxone improves cardiovascular function in a variety of animal models of

shock caused by?and anaphylaxis. Administration of TRH ?also has pressor

effects in these shock models.” (Annals of Emergency Medicine, 8/85)

“TRH has been shown to increase mean arterial pressure during anaphylactic

shock.” (Annals of Emergency Medicine, 5/89) In animal studies of anaphylaxis

the use of TRH, epinephrine, and normal saline were compared. TRH treated

rabbits responded slightly better than those treated with epinephrine (the study

focused on cardiovascular and respiratory parameters.) (Annals of Emergency

Medicine, 5/89)

I started this project with the aim of identifying alternative treatments for

anaphylaxis. I had mistakenly assumed that there are a host of viable and

effective treatment regiments for anaphylactic shock. What I discovered was

that as of today, the only universally accepted therapy for acute anaphylaxis is?

epinephrine. Due to it’s alpha and beta adrinergic effects epinephrine is

miraculously suited for anaphylaxis. It almost seems to be a natural antidote,

a wonder drug with singular abilities in the treatment of anaphylaxis.

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