Anaphylaxis Life Threatening Allergy
The most dangerous allergic reaction is anaphylaxis, which can be a
life-threatening emergency. Anaphylaxis can be triggered by foods, drugs,
injections, insect stings and exertion. After taking a drug, eating food, or
being stung by a wasp, a person may itch, flush, swell, have trouble
breathing, panic and collapse. The foods most commonly associated with
anaphylaxis are cow's milk, eggs, wheat, shrimp, fish, peanuts and other
nuts. The drugs most commonly associated include penicillin,
aspirin, anti-arthritic drugs, morphine, radiocontrast dyes, and
anesthetics.
A woman in her late 20's described the following anaphylactic reaction:
"My teeth started tingling and the inside of my throat was itchy...my
palms got red and swollen. I felt light-headed and agitated. My heart
started to race...by the time I got to the emergency my entire body had
broken out in a rash and my feet were so swollen my boots wouldn't come off.
But things got worse as soon as I walked in...I couldn't breathe and I began
to panic. I felt I was going to die. The doctor in charge was very short
with me. He told me to get a hold of myself, that I was just making things
worse, but I was out of control. I was terrified and wanted to pass out but
couldn't."
Many by-standers and even physicians do not appreciate the gravity of the
allergic crisis. Immediate treatment with injected adrenalin, antihistamine,
steroids and life support may be necessary to rescue the anaphylaxis victim.
Campbell et al stated:" clinicians misdiagnose as many as 57% of ED patients
presenting with anaphylaxis. Even when anaphylaxis is correctly diagnosed,
clinicians in emergency departments fail to administer epinephrine up to 80% of
the time…Anaphylaxis symptoms can progress quickly, over minutes to hours. Fatal
food anaphylaxis can progress to respiratory and cardiac arrest in a median time
of 30 minutes, insect venom-induced anaphylaxis has a median time of 15 minutes
to cardiac arrest, and medication-induced anaphylaxis in a hospital setting has
a median time of 5 minutes to cardiac arrest. (Ronna L. Campbell et al Emergency
department diagnosis and treatment of anaphylaxis . Ann Allergy Asthma Immunol.
2014;113:599-608.)
A second, late phase of anaphylaxis can develop into a prolonged illness if
left untreated. The initial immune response recruits other immune responses.
Anaphylaxis is unpredictable and is not caused by a single mechanism. Lethal
events include:
- tongue and throat swelling, obstructing the upper airway
- severe asthma and/or lung swelling with failure of respiration
- shock caused by sudden movement of water from blood into tissue spaces
(edema)
- heart rhythm abnormalities and cardiac arrest
Sudden death occurs rarely and randomly as a tragic consequence of eating
a reactive food, often in a restaurant. The actual trigger for anaphylaxis
is seldom known with any certainty, although often a single agent such as
traces of peanut oil in a salad or dessert may be blamed. Previous
occurrences of severe asthma attacks, whole-body hives, local swelling
reactions of the tongue, throat, and face; general swelling of the
extremities and sudden onset of breathing difficulty suggest increased risk
of life-threatening anaphylaxis.
Reports of fatal anaphylaxis are rare and there is a conspicuous absence
of systematic studies of the phenomenon.
Sampson et al reported on 13 children and adolescents with fatal and
near-fatal food anaphylaxis. All 13 had asthma with previous serious
reactions to foods - peanuts (4), nuts (6), cows milk (2), and egg (1). The
six patients who died had itching or tingling in the mouth, tightness of the
throat, irritability, abdominal pain or vomiting within 3 to 30 minutes of
eating the food. None of the fatalities had self-injected epinephrine. All
of the survivors received epinephrine within 30 minutes of the onset of
symptoms. Anaphylaxis was rapidly progressive and uniphasic in 7 patients
and biphasic in 3 who had early oral and abdominal symptoms followed by a
1-2 hour remission, followed by increasing respiratory symptoms, hypotension
and death. Three children who survived had a protracted course requiring
ventilator support and treatment with vasopressors for 3 to 21 days after
the onset.
This report emphasizes the potential severity of food reactions and the
importance of prompt administration of epinephrine. The authors suggested
that: " Factors believed to have contributed to the fatal outcome included
the patients' denial of symptoms, reliance on antihistamines alone for
treatment, and failure to administer epinephrine (adrenalin) immediately."
All the children in the study had asthma as part of their allergic pattern.
Typical symptoms of a a major reaction were itching and swelling sensation
of the lips, mouth and tongue, followed by nausea, stomach cramping,
vomiting, hives and difficulty breathing.
Anaphylaxis can be triggered by exertion after eating certain foods and
may be responsible for sudden deaths in healthy athletes as well as people
with known asthma and food allergy who exercise with unaccustomed vigor.
Allergy patients are cautioned to exercise in gradually graded increments,
watch food intake before athletic events, and avoid sudden, unaccustomed
exertion. In one patient wheat was the sensitizing food, and anaphylaxis
began with exertion 40 minutes following ingestion. His reactive pattern
began with itching during exertion, followed by hand swelling, and
generalized redness, and then hives broke out. He experienced drowsiness and
shortness of breath. Within minutes he would lose consciousness. Studies of
this pattern of reactivity showed elevated blood levels of histamine and an
increase in blood acidity. The oral intake of sodium bicarbonate (3.0 grams)
taken before exertion was successful in blocking this severe reactivity.
In the USA from 2008 to 2010, the most common cause of anaphylaxis death was
drugs (58.8%, or 1446 deaths out of 2458). Most deaths (58.5%) were in inpatient
facilities. Identified drugs: 149 were antibiotics (most commonly penicillins,
followed by cephalosporins, and then sulfa drugs and macrolides); 100 deaths
from radiocontrast agents used in diagnostic imaging, and 46 deaths from cancer
chemotherapy. The remaining medications were serum, opiates, antihypertensives,
nonsteroidal anti-inflammatory drugs, and anesthetics. *
Anaphylaxis Lottery
We can view an anaphylactic attack not just as a single dramatic event
but as an avalanche in a series of allergic calamities that stretch out over
time. A major event may follow many lesser reactions that stretch out months
or years in advance. Sometimes, an anaphylactic reaction heralds the onset
of prolonged hypersensitivity, a chronic illness. A severe reaction to an
antibiotic, an intravenous dye used in X-Ray studies, and reactions to foods
may herald the onset of chronic hypersensitivity. Occasionally, a specific
target organ is the focus of anaphylactic damage—the lungs in anaphylactic
pneumonia, the thyroid in a patient reacting to an X-Ray dye containing
iodine, the brain in a patient who reacted to prawns, or the GI Tract in a
patient reacting to an antibiotic.
Little Anaphylaxis- Panic Attacks
Anaphylaxis can occur at a lower intensity and recur at frequent
intervals; frightening, but not life-threatening. While big anaphylaxis
leaves you fighting for your life, little anaphylaxis results in milder
symptoms, which leave you uncomfortable, anxious, and perhaps a little
puzzled. Many people report a recurrent symptom-complex after eating
reactive foods with itching, flushing, chest pain and tightness, shortness
of breath, sometimes acute abdominal pain or intense headache, and often
with anxiety or fear. Alarmingly fast heart action and irregular heart
rhythms are also associated. Moderate anaphylaxis may be diagnosed as "panic
attacks" because of the fight-and-flight arousal accompanying the immune
response. Psychiatrists may prescribe tranquilizers without inquiring about
allergenic triggers which are usually foods, drugs, or airborne chemicals.
Many food allergic patients end up in the wrong department of the hospital,
investigated for heart or neurological problems, or they get trapped in a
psychiatric ward under sedation and suspicion.
Management Policy
We have managed many patients with food allergy and no-one
has died of anaphylaxis. Minor anaphylactic reactions resolve spontaneously
and are common. Since serious reactions are impossible to predict a good
protective policy has to balance caution against unreasonable fears. If an
allergic person knowingly risks eating reactive foods, some protection might
be available with a dose of antihistamine taken before the meal.
Antihistamines are more effective as preventive medication than as treatment
medications once the allergic reaction is underway.
Intravenous dyes used in X-rays studies are known cause anaphylaxis and
it is generally believed that premedication with an antihistamine will
prevent this. Normal antihistamines such as benadryl and chlortripalon are
often included in anaphylaxis kits. An at-risk person who is traveling or
otherwise taking chances by eating foods that may be allergenic may be best
to take a daily long-acting antihistamine such as chlortripalon. The drug
ketotifen (Zaditen) may be used for long-term preventive therapy.
Epinephrine
Campbell et al wrote:
”Anaphylaxis is a serious allergic reaction that frequently involves multiple
organ systems, is rapid in onset, and may cause death. The management of
anaphylactic reactions occurs most commonly in the emergency department (ED),
placing emergency care providers on the front line of medical intervention for
these patients. Epinephrine is the treatment of choice for anaphylaxis and
delayed administration of epinephrine has been associated with increased risk of
death.” They were concerned about dose errors in ED. They stated:” Epinephrine
is supplied in 1:1,000 and 1:10,000
formulations. Both formulations are used in the ED, but the low frequency of
epinephrine use in a high-stress context can lead to errors in choosing the
correct formulation.
Anyone at risk should carry an emergency kit containing injectable
adrenalin, an antihistamine and oral prednisone and self-administer these drugs as soon as a
major reaction begins. This is similar to equipping your home or car with a
fire extinguisher - you may never use the kit, but it is available just in
case. The easiest way to administer adrenalin is with an auto-injector EpiPen, which is simply pressed into the skin and a measured dose is
injected. Autoinjectors are more expensive than manual injection. Previously the wholesale cost of the
autoinjectors was U.S. $75.00 compared with U.S.$ 3.00 for the 1:1,000 vial of
epinephrine. More recently, the cost of autoinjectors has increased
substantially. Currently, EpiPens are only available in packages of two and have
an average wholesale price for the 0.15-mg or 0.3-mg dose of U.S. $730.33, while
the average wholesale cost of the 1-mL 1:1,000 vial of epinephrine is U.S.
$15.00. The generic epinephrine autoinjector, Adrenaclick, has an average
wholesale price of U.S. $103.50 or as a two-pack for U.S. $206.98. Prefilled
epinephrine syringes have been suggested as a potential low-cost alternative to
epinephrine autoinjectors and have been shown to be stable and sterile three
months after preparation.
The standard ADULT dose of epinephrine is 0.3 to 0.5 cc of a 1:1000
solution.
Children 0.01 cc/kg up to 0.3 cc; intramuscular injection is preferred in
children to speed absorption.
The injections can be repeated twice every 10 to 15 minutes if symptoms
persist or worsen. If the first dose was given subcutaneously, the second
dose should be given IM to speed absorption. The intravenous route is
avoided unless there is shock.
Prednisone is taken orally in the dose range of 20-40 mg after the
adrenalin has been injected. Family and friends should know how to
administer the emergency drugs. If the drugs are given soon enough,
catastrophe can be prevented.
Antihistamine, Benadryl (diphenhydramine) Adults 50 mg IM or IV:
1.0-2.0 mg/kg for children.
Prednisone 10-40 mg orally or hydrocortisone IV 5 mg/kg
If blood pressure drops and does not respond to adrenalin injection, a
large bore IV needle is inserted, and infusion of normal saline is begun.
Treatment using H1 and H2 blockers, as well as glucocorticoids, can be
administered IV. If breathing problems persist, admission to an intensive
care unit is required.
When to Act
The problem often is to decide when to push the panic button, use the
drugs and rush to the emergency department. Minor to moderate anaphylactic
reactions occur at a much higher frequency than the potentially fatal
reactions. Many false alarms occur in patients with recurring minor
anaphylaxis whose attacks usually resolve with or without treatment. The
best idea is to play it safe by administering the blocking drugs with the
onset of anaphylactic symptoms. Call an ambulance with the onset of any
mouth or throat swelling, difficulty swallowing or serious breathing
difficulty. Skilled paramedics can administer adrenalin, treat airway
obstruction and shock. Patients with recurrent anaphylaxis, especially where
the cause is difficult to determine, can be helped with a prolonged,
preventive course of daily prednisone and antihistamine.
