CM- Sneezing, Wheezing, Allergies Flashcards
What is the total prevalence of allergic rhinitis?
How does the prevalence change with age?
How many years is a person exposed to an offending allergen to get rhinitis?
20% and decreases with advancing age
Most ppl develop symptoms by 20 and require 2 years of exposure to the offending allergen
What causes allergic rhinitis?
What happens in the early phase and late phase?
Allergen deposits in the nasal cavity where it interacts with mast cells and basophils to crosslink IgE to degranulate the cells
Early phase (15-20 minutes post exposure):
itching, sneezing, runny nose, congestion
-histamine, kinins, PGD2, LTBCDE4
Late phase (4-6 hours)
- eosinophils, basophils, neutrophils, same reactive substances as early phase
- TH2 lymphocytes play a role as a source of IL4 (IgE production) IL5 (eosinophil activation)
- ICAM, VCAM upregulate to direct inflammatory cells to the site
What symptoms are associated with allergic rhinitis?
- paroxysmal sneezing, itching, rhinorrhea (clear)
- seasonality
- eye or chest symptoms
What symptoms are associated with non-allergic rhinitis?
- congestion (no sneezing/itching)
- postnasal drip
- minimal eye irritation
What are “red flag” symptoms of rhinitis?
- unilateral -polyps/deviated septum
- bleeding
- pain
Upon physical examination, how do the turbinates differ with allergic rhinitis and non-allergic rhinitis?
How are they similar?
Allergic:
pale, blue and edematous
Non-allergic:
erythematous and edematous
Similar in that they are both edematous
What 3 areas of the body should be the focus for physical examination of suspected rhinitis?
Eyes, ears and upper airway
What are the classic features seen in the eyes for someone with rhinitis?
- conjunctivitis
- periorbital cyanosis (“allergic shiners”)- sign of venous congestion in addition to nasal obstruction
- Denny Morgan lines (extra skin creases under medial aspect of the eye)
Nasal polyps can cause rhinitis symptoms independent of allergies. What clinical feature should make you suspicious of nasal polyps?
Loss of smell and taste
What are the most common seasonal allergies?
What are the most common perennial allergies?
Seasonal :
Pollen (mountain cedar, tree, grass, weed)
Perennial:
dust mites, pets, cockroaches, mold, latex
What is vasomotor rhinitis?
When does it present? How does it differ from allergic rhinitis?
What exacerbates it?
It is perennial and is characterized by:
- nasal obstruction
- rhinorrhea
- post-nasal drip
LITTLE TO NO ITCHING**
It is exacerbated by irritants (strong odors) and weather changes
What is rhinitis medicamentosa?
Prolonged (several weeks) use of topical decongestant sprays lead to rebound nasal congestion and tachyphylaxis (dependency on the medication)
In addition to nasal sprays, what other medications can cause rhinitis?
oral contraceptives
antihypertensives
conjugated estrogen
What are the main differential diagnoses for allergic rhinitis?
- Allergic- seasonal/perennial
- endocrine/hormonal - pregnancy
- infectious- URI, sinusitis
- medication induced
- non-allergic - vasomotor
What are the steps to diagnosis of allergic rhinitis?
- get a careful history! (much more important than the physical exam)
- nasal smear with eosinophilia is suggestive
- allergy skin testing is most accurate and preferred method but must be done by a specialist
- RAST (Immunocap) testing- detects specific IgE in vitro
What is RAST?
What are the benefits?
It detects in vitro specific IgE
RAST to dust mites and pets is a cost effective way to see if that is the cause of the allergic rhinitis before avoidance measures need to be taken
What is the most preferred and most accurate method for diagnosing allergic rhinitis? What is the drawback?
Allergic skin testing- the drawback is that it is limited to specialists
What type of allergic rhinitis usually can be diagnosed by history alone?
seasonal allergies
When would it not be necessary to perform testing for specific IgE?
If it is allergic or vasomotor rhinitis that is responding to conventional treatment.
What is the 3 tiered approach for rhinitis therapy?
- Allergen avoidance
- Pharmacotherapy (antihistamines, decongestants, anticholinergics, glucocorticoids, cromolyn LT modifiers)
- Immunotherapy
What are the 4 main categories of drugs for rhinitis therapy?
- antihistamines
- anti-inflammatory- glucocorticoids, cromolyn, LT modifiers
- decongestants
- anticholinergics
When is immunotherapy used?
How does it work?
How long does it last?
It is used when the patient does not respond to pharmacologic treatment.
It is the only therapy to reduce allergic sensitivity.
Weekly doses of allergen extracts are given in the physicians office for 3-6 months to build up tolerance. You can also do a rapid one day desensitization but it requires monthly maintenance doses.
Effects last 3-5 years and there is partial tolerance
What is anaphylaxis?
What are the four major organ systems affected by anaphylaxis?
How many need to be affected for it to be “officially” anaphylaxis?
It is an immunological reaction caused by prior sensitization with production of antigen specific IgE followed by antigen exposure resulting in mediator release from mast cells and basophils.
- Cutaneous
- Respiratory
- Cardiovascular
- GI
Atleast 2 need to be affected to indicate anaphylaxis
What is an anaphylactoid reaction? How does it differ from anaphylaxis?
The reaction is clinically indistinguishable between anaphylactoid and anaphylaxis.
The difference is that anaphylactoid is NOT IgE mediated, and does not require prior sensitization.
Anaphylactoid- complement activation from immune complexes generate C3a and C5a which trigger mediator release from mast cells and basophils
What are the cutaneous symptoms of anaphylaxis?
- urticaria and angioedema
- flushing
- pruritis without rash
What are the respiratory symptoms of anaphylaxis?
- dyspnea, wheezing
- upper airway angioedema
- rhinitis
What are the cardiovascular signs of anaphylaxis?
- hypotension
- syncope
- dizziness
What are the physiological effects of histamine?
- smooth muscle contraction
- vascular permeability
- vasodilation
causing: flushing hypotension wheezing urticaria (hives) /angioedema (deep tissue swelling)
What are the physiological effects of PGD2?
- peripheral vasodilation
- coronary vasoconstriction
- bronchoconstriction
causing:
flushing
bronchospasm
hypotenstion
What are the physiological effects of LTC4, D4, and E4?
- smooth muscle contraction
- vascular permeability
- chemoattractants
- mucus production
causing:
bronchospasm
hypotension
What are the physiological effects of tryptase?
Inactivates bradykinin, activates Ang I.
There is no known clinical effect but it can be used as a marker for MAST CELLS. It will elevate during an anaphylactoid or anaphylaxis reaction
What is the specific marker for mast cells that can be measured in serum?
Tryptase
When do you give a person epinephrine for anaphylaxis?
Any time it occurs- they do NOT have to be in shock to get epinephrine
How is someone having a vasovagal attack differentiated from someone with anaphylaxis?
Vasovagal shock causes sudden collapse like anaphylaxis but:
- no pruritis
- no respiratory symptoms
- triggered by painful injections or anxiety
- hypotension resolves when they lay recumbent
- pale NOT red
- bradycardia NOT tachycardia
What is a common mimic of the throat swelling seen in anaphylaxis?
Vocal cord dysfunction- differentiated because anaphylaxis will have orofacial swelling that lasts several hours
What is the most common type of IgE mediated anaphylaxis?
What should people with this type of anaphylaxis do?
Insect venom
Nationwide- yellow jackets
Texas- fire ants
They should get skin testing to hymenoptera and if positive undergo immunotherapy
What are the 4 most common causes of anaphylactoid reactions?
- radiocontrast media
- blood/blood products
- hemodialysis membranes
- IVIG
What is the treatment for anaphylaxis?
- Early recognition- assess severity of rxn
- Supplemental O2, IV fluid, vitals, cardiac monitoring
- ABCs (airway, breathing, circulation)
- Epi is first choice
- H1 and H2 antagonists, glucocorticoids
Why is epinephrine the first choice for treating anaphylaxis?
B agonist effects:
- increase blood pressure by peripheral vasoconstriction
- reverse bronchoconstriction
- ionotropic and chronotropic effects on the heart
- inhibit mediator release by increasing cAMP.
When should rapid desensitization be used?
- allergy to an essential therapeutic agent
2. systemic reactions to insect venom
What are the 3 things that characterize asthma?
- inflammation of the airway
- hyperresponsiveness (to a trigger)
- reversible obstruction
What is the presentation of someone with asthma?
When are the symptoms more likely to occur?
- episodic wheezing
- chest tightness
- SOB and or cough
The symptoms vary throughout the day and tend to worsen in the presence of aeroallergens, irritants, exercise or at night. There is a genetic component to asthma
May also have:
nasal secretions, polyps, mucousal swelling, atopic dermatitis/eczema, other signs of allergic skin problems
Asthma classification used to be made on _______ but now it is made on _________.
Used to be based on severity, but now it is based on control which can be assessed regardless of treatment and is expected to change over time in a given patient
When is asthma severity assessed?
When is asthma control assessed?
Severity: during initial presentation if they are not currently taking long-term control medication, severity guides the clinical decision of what medications are appropriate
Control: determines whether to maintain or adjust therapy (step up or step down). It can be well controlled, not well controlled or very poorly controlled
What are the 2 domains used to assess control?
- impairment- effect of asthma on current situation like:
- symptoms
- use of inhaler
- lung function - risk- affect of asthma on adverse events like:
- exacerbations
- loss of lung function
- side effects of treatment
How do you verify the reversibility of obstruction in asthmatics?
Pulmonary function tests- FEV1 will be less than 80% in poorly controlled asthmatics. After administration of a bronchodilator (B2 agonist) there should be a 12% increase (200ml) in FEV1.
Other asthmatics require corticosteroids to document reversibility of airway obstruction.
What are the differential diagnoses for adult asthma?
- vocal cord dysfunction
- obesity
- COPD
- interstitial lung disease
What are the differential diagnoses for a child with asthma?
- vocal cord dysfunction
- vascular rings
- foreign bodies
What is vocal cord dysfunction?
Condition where the patient has episodic and inappropriate adduction of their true vocal cords leading to wheezing, shortness of breath, cough and throat tightness.
Attacks can be precipitated by exercise, stress, odors
What are the perennial allergens that trigger asthma?
Pets
Cockroaches
dust mites
indoor molds
What is skin testing? When is this appropriate?
Pricking skin test can be done to determine a person’s sensitivity to certain allergens. IF they are allergic wheals will form around the prick.
There is a control prick of histamine to compare to.
What is the “high level” of grass, weeds, tree pollen, mold?
Grass- 20
weeds- 50
tree pollen -90
mold - 13000
What is the progression of medication as asthma increases in severity?
All levels of asthma use SABA and this is also used for rescue therapy (immediate symptom relief)
Preferred initial controller therapy is ICS (inhaled corticosteroids) for patients with persistent asthma
Step 3: ICS + LABA or ICS+LTRA
Most severe and persistent asthma uses ICS+LABA+ oral corticosteroid and an anti-IgE drug is considered
How do asthmatics monitor themselves?
Peak flow meter is a portable cheap easy way to measure expiratory flow rate.
Results indicate degree of obstruction, so can be used for self-monitoring
What are asthma action plans based on?
symptoms of asthma ans peak flow rate.
The patient and physician have a plan for medication regiment for certain levels.
