Untitled Essay, Research Paper

TREATING ANAPHYLAXISIn 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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