EMT Ch. 21- Allergy & Anaphylaxis

number of deaths per year in US attributed to systemic anaphylaxis

1500-2000

lifetime incidence of systemic anaphylaxis in adults

2-8%

allergic reaction

exaggerated immune response to any substance; not caused directly by outside stimulus

chemicals released that contribute to allergic reaction

histamines & leukotrienes

anaphylaxis

extreme, life threatening allergic reaction involving multiple organ systems

signs of anaphylaxis

widespread urticaria, angioedema, wheezing, stridor, hypotension, increased capillary permeability, persistent GI dysfunction, confusion

urticaria

most common sign; hives; small areas of generalized itching/burning appearing as multiple small/raised areas on skin

angiodema

most common sign; areas of local swelling

wheezing

high-pitched, whistling respiratory sound; typically heard on expiration; results from bronchospasm/bronchoconstriction & increased mucus production

stridor

high-pitched respiratory sound; typically heard on inspiration; possible upper airway narrowing

common allergen- food

• account for 30% of deaths

• symptoms may take more than 30 min to appear

• may not include presence of skin signs

• abdominal cramping, vomiting, diarrhea common

• reaction can be severe, involving cardiovascular/respiratory system

• pt may be unaware of exposure

common allergen- medication

• particularly antibiotics & NSAIDS

• reaction may occur <30 min if injected

• reaction may occur >30 min if administered orally

common allergen- plants

dust, pollen, mold, mildew, other organic materials

common allergen- chemicals

• certain chemicals, makeup, soap, hair dye, latex, etc

• most prominent in healthcare is late

common allergen- insect bites/stings

• envenomation by insect bite/sting

• may cause localized reaction, leading to swelling/itching, or anaphylaxis

envenomation

act of injecting venom by insects/animals

approx. number of Americans allergic to venom of stinging insects & deaths

2 million; 62/yr

if the stinger is not removed from the skin, it can continue injecting venom for up to:

20 min

common area where ant bites are found:

feet & legs

signs/symptoms of insect stings/bites

• sudden pain

• swelling

• localized heat

• widespread urticaria

• redness usually at site of injury

• possible wheal

wheal

raised, swollen, well-defined area on skin; usually whitish & firm

signs/symptoms of more severe anaphylactic cases

• stridor, bronchospasm, wheezing

• chest tightness

• coughing

• dyspnea

• anxiety

• GI complaints

• hypotension

• possible respiratory failure & confusion

time after exposure where 2/3 of anaphylaxis deaths occur:

<30 min

until a field impression of allergic reaction is firmly established,

be mindful of other potential causes of respiratory distress

allergic reactions may present as:

respiratory/cardiovascular distress in the form of shock

if general impression finds the pt anxious/in distress:

immediately call for ALS backup

although respiratory complaints are most common, some pts may present w/

circulatory distress

treatment priority for anaphylactic pts:

epinephrine

if anaphylaxis is suspected or if reaction appears to be worsening:

immediately transport after administering epinephrine

SAMPLE history

• have any interventions already been completed?

• has the pt experienced a severe allergic reaction in the past?

• be alert for any statements regarding ingestion of foods commonly causing reactions

• inquire about the presence of GI complaints

signs/symptoms of allergic reaction- respiratory system

• sneezing/itchy, runny nose (early sign)

• SOB (dyspnea)

• tightness in chest/throat

• irritating, persistent dry cough

• hoarseness

• rapid, labored, noisy respirations

• wheezing/stridor (late sign)

signs/symptoms of allergic reaction- cardiovascular system

• tachycardia (early sign)

• red, flushed, hot skin (early sign) OR pale, cyanotic, cool skin (late sign- vascular failure)

• hypotension (late sign- blood vessels dilate)

signs/symptoms of allergic reaction- skin

• flushed, itching, burning skin, especially over face/upper chest

• urticaria over large areas, internal or external

• swelling, especially of face, neck, hands, feet (low points), tongue; may be localized/generalized

• cyanosis/pallor around lips

• warm, tingling feeling in face, mouth, chest, feet, hands

signs/symptoms of allergic reaction- other findings

• decreasing mental status (early sign of hypoperfusion), mild confusion/lethargy to loss of consciousness/coma

• anxiety- sense of impending doom

• GI problems- nausea, vomiting, cramps

• headache

• itchy, watery eyes

• dizziness

documentation should include:

• signs/symptoms

• explanation for why care path was chosen

• response to treatment

care for stings

remove stinger w/ edge of a sharp/stiff object, ***do not use tweezers/forceps as it may squeeze more venom into wound; gently wash area w/ soap/water or mild antiseptic; remove jewlery around area before swelling begins; position pt w/ injection site slightly below level of heart & apply ice/cold packs

care for all allergic/anaphylactic reaction pts:

• airway swelling, other signs of anaphylaxis (nausea, vomiting, abdominal cramps)

• do not give pt anything by mouth

• place in supine position & give O₂ as indicated

• monitor vitals

• be prepared to provide further support as needed

properties of epinephrine:

increase cardiac contractility & relieve bronchospasm

epinephrine indications

• severe allergic reaction causing ABC compromise or anaphylactic reaction

• check pulse pressure

epinephrine contraindications

• none in life-threatening emergencies

• consult med control if pt has history of heart disease/acute coronary syndrome

epinephrine actions

• vasoconstriction

• increased cardiac contractility

• bronchodilation

epinephrine side effects

• tachycardia

• sweating

• pale skin

• dizziness

• headache

• palpitations

epinephrine dose

adults- 0.3 mg IM; peds- 0.15 mg IM

hold epipen in place for:

3 sec

after injection rub site for:

10 sec

reaction time of epinephrine

1 minute

pts who do not exhibit signs of respiratory compromise/hypotension & do not meet criteria for a diagnosis of anaphylaxis should not be given epinephrine

true

concentration of epinephrine via needle & syringe:

1:1000; 1 mg/mL

adult epipen can be used for any pt over:

66 lbs (30 kg)

method of epinephrine administration for pts weighing <33 lbs (15 kg):

individual dosing (0.01 mg/kg IM) in thigh

Chemicals that are responsible for the signs & symptoms of an allergic reaction to a bee sting include:

histamines & leukotrienes

Which of the following patients would MOST likely have a delayed onset of an allergic reaction?

A 45-year-old male who ingested penicillin

You are assessing a young male who was stung on the leg by a scorpion. He is conscious & alert, his breathing is regular & unlabored, & his blood pressure is 122/64 mm Hg. Assessment of his leg reveals a wheal surrounded by an area of redness. He states that he had a "bad reaction" the last time he was stung by a scorpion, & carries his own epinephrine auto-injector. You should

apply oxygen as needed, clean the area w/ soap & water or a mild antiseptic, & transport him to the hospital

Which of the following would MOST likely provide clues regarding the source of a patient's allergic reaction?

The environment in which the patient is found

A 73-year-old man presents w a generalized rash, which he thinks may have been caused by an antibiotic that he recently began taking. He has a history of coronary artery disease, hypertension, & emphysema. He is conscious & alert, his blood pressure is 144/94 mm Hg, & his pulse is 64 beats/min & regular. You auscultate his breath sounds & hear scattered wheezing, although he is not experiencing respiratory distress. You should:

administer oxygen if needed, transport the patient, & monitor him for signs of deterioration

A 37-year-old male is having a severe allergic reaction to penicillin. He does not have an epinephrine auto-injector, & your protocols do not allow you to carry epinephrine on the ambulance. How should you proceed w/ the treatment of this patient?

Administer oxygen, transport at once, & request a paramedic intercept

A 38-year-old woman was bitten by fire ants while at the park. Your primary assessment reveals that she is semiconscious; has labored breathing; & has a rapid, thready pulse. She has a red rash on her entire body, & her face is swollen. You should:

assist her ventilations w/ 100% oxygen

A 48-year-old male is found unconscious in the garden by his wife. When you arrive at the scene & assess the man, you find that he is unresponsive, has labored breathing, & has hives over his entire trunk. You should:

maintain his airway & assist his ventilations

Epinephrine is indicated for patients w/ an allergic reaction when:

wheezing & hypotension are present

Immediately after giving an epinephrine injection, you should:

properly dispose of the syringe

A 19-year-old female was stung multiple times on the legs by fire ants. She states that she is allergic to fire ants, but does not carry her own epinephrine. The patient is conscious & alert & complains of pain to the area of the bites. Her blood pressure is 122/70 mm Hg, her pulse is 100 beats/min & strong, & her respirations are 18 breaths/min & unlabored. You should:

administer oxygen & transport her to the hospital

After administering 0.3 mg of epinephrine via auto-injector to a 22-year-old female w/ an allergic reaction, you note improvement in her breathing & resolution of her hives. However, she is still anxious & tachycardic. You should:

monitor her closely but recall that anxiety & tachycardia are side effects of epinephrine