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hypersensitivity
- abnormal or excessive immune response to a stimulus/foriegn body
- four types of hypersensitivity reactions
- - types I, II, III, IV
- allergic reaction are usually types 1 or type 4
- chart p 1610 fig 53-2
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chart
- type 1 (anaphylatic): <30 (20-30mins), IgE
- binds to the mast cell or basophils
- type 2: (cytotoxic): 5-12hr- blood issue
- type 3: Immune complex 3-8hr
- type 4: cancer
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causes and triggers of hypersensitivity
- Skin: poison plants, animal scratches, pollen, latex
- injection: bee sting
- ingestion: meds, nuts and shellfish
- inhalation: pollen, dust, mold and mildew, animal dander
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hypersensitivity type 1 (1st exposure)
- Patho:
- - antigen initially stimulates production of IgE antibodies
- IgE antibodies bind to surface membranes of mast cell and basophils
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hypersensitivity type 1 (2nd exposure)
- patho:
- on subsequent exposure:
- - allergens links with IgE antibody attaches to mast cells/basophils
- - triggers degranulation of cells
- - release of chemical mediators from granules in these cells (releasing of cytotoxic molecules
- - the chemical mediators attack target organs
- -- intravascular- anaphylaxis
- -- skin- urticaria, atopic dermatitis
- -- resp- rhinitis, asthma
- -- GI- n/v/d, abd cramps
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chemical mediators in type 1
- histamine: contraction of bronchial smooth muscle thus narrowing the air way, increa mucous secretion (anti histamine block receptor site)
- leukotrienes: airway edema, smooth muscle contraction, incre cap permability
- prostagladins: vasodilation, smooth muscle contraction, incre cap permability (headache)
- kinins: bradykinase, increa vascular permability, stimulates secretion of mucous and nerve fibers
- serotonin: vasocontrictor, stimulates smooth muscle contraction
- platelet activating factor:
- vasodilation, platelet aggregation, incre vascular permability
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Hypersensitivity Type 1 (2nd exposure)
- IgE mediated response
- less severe
- wheal and flare reaction
- atopic reaction
- allergic rhinitis, asthma
- atopic dermatitis
- urticaria
- angioedema
- GI
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2nd exposure
- less severe
- allergic rhinitis
- asthma
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Allergic Rhinitis
(2nd exposure, less severe)
- hay fever, seasonal allergic rhinitis
- type 1 hypersensitivity
- reaction to nasal mucousa with a specif antigen with production of IgE
- nasal mucosa becomes thickened with edema, decre ciliary function, vasodilation, incre capill perm.
- - histamine is major chemical mediator
- - also prostagladins, leukotrienes (s/s sneezing, water eyes, swollen nasal congestion, nothing in chest)
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S/s of allergic rhinitis
- sneezing, watery and itchy eyes and nose
- nasal congestion/problem with smell
- itching of throat ad palate, altered taste
- dry irritating cough, hoarseness
- headache, sinus pain, epitaxis
- sore throat (post nasal drip), clogged ears and decreased sense of smell
- puffiness under the eye, fatigue, irritiability
- can cause: sleep disturbance, snoring
- sore throat- warm salt water gurgle
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DX allergies
- History and PE
- Serum IgE
- Eosinophil counts
- skin test
- - review 1612-1613
- - nursing care/intervention
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Management of allergies
- Pt education:
- Avoidance of triggers:
- - avoid house hold dust (less is best)
- - avoid pollen
- - avoid mold (dampness, draft)
- - avoid pet allergens
- - avoid smoke
- - hygiene
- - safety- meds cold meds cause vasocontriction which can lead to HTN. remember allergies cause vasocontrictio
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Medical management allergy
- Antihistamines
- - H1 receptors, blocks histamine binding
- best: urtucaria, sneezing, excessive secretions ad mild congestion
- s/e sedation, drowiness
- often combined with decongestant
- OTC
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Medical management 2 allergy
- Corticosteriods
- - intranasal preps- flonase, nasacort
- - anti inflammatory effects
- - infection, incr BS, incre BP (holds on to fluid)- no high sodium diet
(saline nasal spray, nettie pot)
- Leukotriene modifers (singular)
- - block the synthesis of leukotrienes
- - long term use
- - s/e mild
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medical management 3 allergy
allergy clinic
- immunotherapy
- - allergen disensitization
- - treat igE mediated disease by injection of allergen extracts
- - administration of gradually increasing doses of specific allergens (trying to give your body a reaction)
- - s/e mild, risk for anaphylaxis
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Nx Dx for allergies
- adaption/lifestyle changes
- safety- meds
- knowledge deficit- knowing the difference between allergies and a cold,do they know what they are allergic to.
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Asthma (2nd exposure, less severe)
- Chronic inflammatory disease of the airways
- - hyperresponsiveness of the airways
- - mucosal edema
- - mucus production
- intermittent and reversible
- common triggers
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Asthma patho
- Reversible and diffuse airway inflammation-airway narrow (take home)
- exposure to trigger/allergens- inflam cascade
- mast cells release chemical mediators- incr inflam response
- - vasodilate (inc blood flow), inc capillary perm
- - bronchconstriction
- - phagocytes: airway infiltrated with eosinophills lymphocutes, neutrophils
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asthma path cont
- results:
- vascular congestion
- edema
- thick tenacious mucus
- bronchial muscle spasm/constriction
- thickening of airway walls
- inc bronchial hyperresponsiveness
- Chronic inflammation- remolding- further airway narrowing
- air can go in but it struggles to go out. - histamine causes inflamm and narrowing of airway
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Asthma classic s/s
- cough with/out mucous production
- - dyspnea
- - wheezing
- other s/s
- chest tightness, use of accessory muscle
- prolong expiration
- diaphoresis, tachycardia cyanosis
- hypoxemia
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Dx asthma
- H/P
- Peak flow- measure the expiration of air
- chest x-ray
- cbc w/diff- to check with infection
- pulmonary function test
- ABG's depending on severity- checking to see how it is perfusing the cells and tissues
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Nx Dx asthma
- ineffective airway
- impaired breathing pattern
- impaired gas exchange
- anxiety
- knowledge deficit
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Nursing management asthma
- maintain airway
- - inc HOB
- - Oxygen
- Peak flow meter
- - measure highest airflow during forced expiration
- - correct usage
- - give pt about dx state, progression of s/s
- - adjunct to asthma management
- IV access ) soften mucous 1/2 NS, NS (be careful bc of HF and HTN...NS has alot of salt)
- reassure family
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treatment and drugs asthma
- rescuer inhaler/SABA
- quick relief, act quickly
- relax bronchial smooth muscle and bronchodilator
- use: stop exacerbation, exercise induced s/s
- beta 2 stimulants
- - first line
- Anticholinegic
- - choice of pt cannot tolerant SABA
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Tx of drugs asthma
- proventil: inhaled SABA
- - relief of acute symptoms, prev exercise induced asthma
- - binds to beta 2 receptors: broncodilation
- listen to pt lungs sounds after u give 15-20mins
- Prednisone Glucocorticoid
- - moderate/severe exacerbations
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Tx and drugs asthma 3
- Flovent: inhaled steriods
- - long term prevention
- - reduces inflam
- - rinse mouth, correct use (give water)
- Salmeterol: long acting beta agonist (LABA)
- - long term prevention, previous excerise induced
- - stimulates beta 2- bronchodilation
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Tx and drugs asthma 4
- Advair: combination med of LABA and long acting inhaled steriod
- - salmetrol/fluticasone
- - control of asthma s/s not acute use
- - teaching: correct usage (review fundamental)
- singular leukotiene Modifer
- - inhibits actions of leukotrienes resp for inflam effects
- - long term control/preventio, can be used with ICA fo persistent
- asthma
- - few side effects well tolerated
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Nx education to reduce ed visit
asthma
- avoid exposure to triggers/irritants: soaps, perfume, chemicals, pets
- no smoking
- remove carpeting
- air filters/humidifer
- hot water wash bedding, covers on bedding
- cold induced: avoidance, scarfs
- prompt intervention, colds URI
- immunization, flu/pne shots
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