understanding allergic reactions - pcom...
TRANSCRIPT
Understanding Allergic
Reactions
Samuel Gubernick, DO
FAAAAI, FACAAI, FAAP
Allergy
• Von Pirquet
– Coined the term
“Allergy” in 1906
• Derived from Greek
word “allos” meaning
changed or altered
state and “ergon”
meaning reaction
• Reaction may be host
protective or injurious
Hypersensitivity Classification
• Gell and Coombs
– Developed classification of hypersensitivity
reactions (1963)
• Type I Hypersensitivity- IgE mediated
• Type II Hypersensitivity- Antibody mediated
• Type III Hypersensitivity- Immune complex
• Type IV Hypersensitivity- Cell mediated
Stages in Symptomatic Allergic Rhinitis
and Asthma
Subsequent
Allergen
Exposures
Initial AllergenExposure
DelayedSymptoms
NaiveAirway
SensitizedAirway
ImmediateSymptoms
Late-PhaseResponse
Early-PhaseResponse
Cellular Participants
in the Allergic Response
• APCs
• Helper T lymphocytes
(TH0, TH2 subclasses)
• B lymphocytes
• Mast cells
• Airway epithelial cells
• Eosinophils
T-Cell Differentiation During Sensitization
IL-2, IL-3, IL-4, IL-5, IL-9IL-10, IL-13, GM-CSF
APC
TH0 Cell
TH2 Cell
MHC II CD4
IL-4Antigen
IgE Antibodies in Allergic Inflammation
Allergen
B Cell
IL-4
Plasma Cell
IgEAntibodies
Mast Cell
AllergenExposure
ActivatedMast Cell
Preformed in Granules
– Preformed mediators
• Histamine
• Tryptase & Chymase
• Heparin
• Condroitin sulfate
• Carboxypeptidase A
• Cathepsin G
• Acid hydrolase
• TNF-a, VPF, VEGF
Newly Generated
– Newly synthesized lipids
• PGD2
• LTC4
• LTB4
• PAF
– Cytokines
• IL-3, 4, 5, 6, 8, 10, 13, 16
• TNF-a
• MIP-1a
• RANTES
• GM-CSF
• b-FGF
• SCF
• TGF-b
• VEGF
• MCP
Immediate allergic reaction
• Triggered when allergens bridge IgE-FceRI
units on mast cell surface
– Histamine, leukotrienes, PGD2, tryptase,
cytokines & other mediators released
– Peak of allergic symptoms within 30 minutes
• Mast cell major cause of anaphylaxis
Late-phase allergic reaction
Mast cell action amplifies this reaction: role of TNF-a & other cytokines and mediators
Recruitment of other inflammatory cells: lymphocytes, monocytes/macrophages, eosinophils, and basophils (as early as 1 hour)
Cytokines and chemokines released by TH2
cells, monocytes, eosinophils
Release of mediators from basophils:
histamine, leukotrienes and cytokines
Symptoms peak in three to eight hours
Early and Late Phase Response
Summary of Allergic Response
Mast Cells
Subsequent AllergenExposures
NaiveAirway
SensitizedAirway
Late-PhaseResponse
Early-PhaseResponse
Initial AllergenExposure
TH2 Cells
AirwayEpithelial
Cells
InflammationAirway DamageHyperresponsiveness
CytokineRelease
Leukocyte Influx:EosinophilsT LymphocytesBasophilsNeutrophils
SensitizedTH2 Cells
SensitizedMast Cells
Definition of Allergic Rhinitis
• Inflammation of the membranes lining the nose
• Characterized by one or more of the following:
– congestion
– itching
– sneezing
– rhinorrhea
– postnasal drainage
• IgE-mediated reaction to a specific aeroallergen
Types of Rhinitis
• I. Allergic rhinitis
– A. Perennial
– B. Seasonal
– C. Episodic
• II. Nonallergic rhinitis
– A. Vasomotor rhinitis
– B. Gustatory rhinitis
– C. Infectious
• 1. Acute
• 2. Chronic
– D. NARES
• III. Occupational rhinitis
– A. Caused by protein and
chemical allergens, IgE-
mediated
– B. Caused by chemical
respiratory sensitizers,
immune mechanism
uncertain
– C. Work-aggravated rhinitis
Types of Rhinitis - continued
• IV. Other rhinitis syndromes
• A. Hormonally induced– 1. Pregnancy rhinitis
– 2. Menstrual cycle related
– 3. Thyroid
• B. Drug-induced– 1. Rhinitis medicamentosa
– 2. Oral contraceptives
– 3. Antihypertensives, other CV
– 4. Aspirin/NSAIDs
– 5. Other drugs
• C. Atrophic rhinitis
– D. Rhinitis associated with inflammatory-immunologic diseases
• 1. Granulomatous infections
• 2. Wegener graulomatosis
• 3. Sarcoidosis
• 4. Midline granuloma
• 5. Churg-Strauss
• 6. Relapsing polychondritis
• 7. Amyloidosis
Conditions that may mimic
symptoms of rhinitis
• A. Nasal polyps
• B. Structural/mechanical
– 1. Deviated septum
– 2. Adenoidal hypertrophy
– 3. Trauma
– 4. Foreign bodies
– 5. Nasal tumors
– 6. Choanal atresia
– 7. Cleft palate
– 8. Pharnygonasal reflux
– 9. Acromegaly
• C. CSF rhinorrhea
• D. Ciliary dyskinesia
Comorbid Conditions
• Asthma– Allergic rhinitis occurs in over 75% of asthmatic patients
– 15% of patients with AR have asthma
– “One airway, one disease”
• Allergic Conjunctivitis
• Nasal polyposis
• Eustachian tube dysfunction & otitis media
• Rhinosinusitis
• Atopic dermatitis
• Lymphoid hypertrophy / obstructive sleep apnea
Allergens
• Seasonal
– Tree pollen
– Grass pollen
– Weed pollen
– Mold spores
• Perennial
– House-dust mites
– Animal dander• Dogs, cats
• Mice and rats
– Cockroaches
– Mold spores
– Occupational
allergens
House Dust Mites
• Dermatophagoides pteronyssiunus
• Dermatophagoides farinae
• Blomia tropicalis
• Live in bedding, upholstered furniture,
stuffed animals and carpet.
• Feed on human skin scales.
• Grow best in relative humidity above
50-70%.
House Dust Mite Control
• Encase mattress, box-springs and pillows
• Wash bedding weekly at 130° F
• Remove stuffed animals
• Reduce humidity
• Second line – remove carpeting and upholstered
furniture, HEPA vacuum
• Air filters not effective
Cockroach Allergen
• Blattella germanica most common in U.S. inner cities
• Allergens found in cockroach feces and typically carried on larger particles (>10µM)
• Prevalence of sensitivity to cockroach:
– 18.1% in general population
– 33.2% in asthmatics
Allergen avoidance - Cockroach
• Eradicate cockroaches with appropriate gel-type,
non-volatile, insecticides
• Eliminate dampness
• Seal cracks and crevices in floors and ceilings
• Removal of food and water sources
• Thorough cleaning of all surfaces including floors,
cabinets, appliances, and fabrics to remove
allergen
Exposure to A alternata in US Homes is
Associated with Active Asthma
Association Between Spore Peaks and
Asthma Hospitalizations
Salvaggio et al. JACI. 48:96,
1971
•First documented by Salvaggio 1971
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ER
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Sp
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Me
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ER Visits Spores
Mold Avoidance
• Avoid barns, hay, raking leaves, and mowing grass
• Proper building maintenance, dehumidification, air
conditioning, and increased ventilation are helpful
• Ensure dry indoor conditions - mold growth indoors
can be inhibited by reducing moisture and humidity
• Use bleach, ammonia, etc to remove mold from
bathrooms and other wet spaces
• Humidifiers and vaporizers increase indoor humidity
and can become contaminated with mold
Cat and Dog Allergens
• Particles that carry cat and dog allergens can be small
(2-10μm), become airborne with minimal disturbance and
remain airborne for hours.
• Travel on particles that are passively transferred.
• Are ubiquitous in public buildings and moderate exposure
in communities with domestic cat ownership is
unavoidable.
• Homes with pets have allergen levels ~100x higher than
homes without
Pet allergen avoidance
• Remove pets from home is best
• Keep the pet outside at all times
• Keep pets out of bedroom
• Vacuum carpets, mattresses and upholstery
• Air cleaners
• Wash pet regularly
Cat Allergen in Home Declines
Slowly After Pet Removal
Fel d 1 content in the dust from homes after removal of a cat
Wood et al JACI 83:730,1989
Pollen allergen avoidance
• Remain indoors with windows closed at peak pollen times
• Trees release pollen early in the morning around dawn
and counts near the source will be highest in the morning.
Urban counts will increase as the pollen travels toward the
area and usually peaks at the middle of the day. Avoid the
outdoors between 5 a.m. and 10 a.m - when counts are
the highest. Pollen counts decrease by late afternoon.
• Wear sunglasses
• Use air-conditioning, where possible
• Install car pollen filter
Vasomotor Rhinitis
• Vasomotor rhinitis
– Perennial
– Nasal congestion and post-nasal drip
– Mechanism unknown - vascular and/or neurological
dysfunction of nasal mucosa ?
– Females predominance, 40-60 years
– Triggers
• change in temperature, humidity, barometric pressure
• Irritants - perfume, tobacco smoke, paint, ammonia
• emotional stress
Test results alone
do not make a diagnosis
• Correlation of allergy test results with the
patient’s history and physical exam, the
environmental history, the disease process, and
a thorough knowledge of all relevant allergens in
a specific location is essential in making an
appropriate diagnosis.
• Bottom line – interpret allergy testing in light of
the clinical setting.
• Therefore, the practice of “remote allergy” or
diagnosis by testing alone is not acceptable.
Total IgE
• Over 25% of patients with allergic rhinitis have
normal total IgE levels.
• Up to 20% of nonallergic patients have elevated
total IgE levels.
• Therefore, total serum IgE is not a good
screening test for allergy.
Chronic cough
How is cough produced?
• Cough receptors stimulated
• A signal is sent to brain/cough center
• A signal is sent back to respiratory tract
• Starts with deep inhalation and then a
forced exhalation with closed
glottis/windpipe. Air gushes out at a high
speed of 300 miles/hour
Is it really important to know
• Character
• Timing
• Presence or absence of sputum production
• Associated complications
Children are not little adults!
Frequent Throat Clearing
• When can it be abnormal?
• Abnormal if waking you up at night
• Causes: Habit, Anxiety, Allergies, Sinus
Disease, Reflux
History
• Triggers: Talking, laughter, walking, running, strong smells, perfumes
• Timing: Daytime vs nighttime
• Relationship with meals
• Preceding Events:
Viral URI, Recent Immigration from a developing country, foreign travel
• Analysis of cough sound: Pediatric vs Adult
• Review of systems is very important
Analysis of Cough Character
Cough Character Potential Etiology
Barking or brassy Croup, tracheomalacia,
habit cough
Cough productive of
casts
Plastic bronchitis
Honking Psychogenic
Paroxysmal (with or
without whoop)
Pertussis/Parapertussis
Staccato Chlamydia in infants
Physical Examination
• Thick, yellow postnasal drip visible in
oropharynx: think chronic sinusitis
• Look into ears to rule out wax impaction
and other causes (Arnold’s Nerve)
• Look at nails for clubbing (CF, etc.)
• Check for thyroid masses
• Look for signs of atopy
Most Common Causes of
Chronic Cough
• The following account for >90% of causes
in a non-smoker who is not on an ACEI
– Upper Airway Cough Syndrome
– Asthma
– Reflux Disease
– Non-asthmatic Eosinophilic Bronchitis/ NAEB
(? Uncommon in the US)
Four basic steps for evaluating
chronic cough
• Stop ACE-inhibitor (1-3 months)
• Stop Smoking (1 month)
• Chest XR
• Spirometry/PFT (Pre- and Post)
Common Pitfalls
• Failure to consider common
extrapulmonary causes
• Insufficient dose of medication or duration
of therapy
Classification based on
duration of cough
• Acute cough lasting < 3 weeks
• Sub-acute cough lasting 3-8 weeks
• Chronic cough lasting > 8 weeks
Causes of acute cough
• Common cold
• Acute bronchitis
• Allergic rhinitis
• Acute bacterial sinusitis
• Pertussis
• COPD/Emphysema exacerbation
Post-Viral Cough
• A very common form of nonspecific cough
• Usually dry
• Due to increased cough receptor sensitivity
• NOT cough variant asthma
• May respond to albuterol or inhaled steroids
• Children in daycare – 6-12 URIs per year
Bordetella Pertussis
• Pertussis vaccine is about 80% effective
• Last DPT given at approximately 5 yo
• Immunity wanes 3 years post vaccination and
children susceptible within 5-10 years
• Characteristic “Whoop” is absent in teens and
adults
• Teens/adults not seriously ill and serve as
reservoirs for the disease
Red Book 26th ed American Academy of Pediatrics
Pertussis
When to suspect & Whom to treat?
• Suspect and treat if a clear cut history of exposure
• Suspect and treat if cough and vomiting (?)
• Erythromycin is the drug of choice; however, unless administered early, it does not alter the course of the disease
Causes of sub-acute cough
Sub-acute cough: 3-8 weeks duration
• Post-infectious
• Pertussis
• Sub-acute bacterial sinusitis
• Asthma
• Allergic rhinitis
Foreign Body Aspiration
• Most children with foreign body aspiration
present within 24 hrs
• 20% present > 1 week after the incident
• Nonobstructive or partially obstructive can
go unnoticed
• Foods – 80% , Peanuts, hot dogs, hard
candy most commonly removed
• Bilateral is rare but can occur
Causes of chronic cough
• Postnasal drip syndromes (PNDS)
(1) Allergic rhinitis
(2) Nonallergic rhinitis
(3) Chronic bacterial sinusitis
• Asthma
• GERD
• Eosinophilic bronchitis
• Chronic bronchitis
• ACE-inhibitor induced cough
Strategies in Cough
• “Anatomic-diagnostic” protocol
• Full investigation for common causes in all patients
• Empiric trials of therapy without routine investigation
The Anatomic Diagnostic
Protocol
• By Richard Irwin, et al (1981)
• Prospective study
• Not randomized or blinded (limitation)
• Offers framework for many of the
published diagnostic algorithms
• Success Rates of 84-98%
Irwin RS et al. Am Rev Respir Dis. 1981;123: 413-417
Upper Airway Cough
Syndrome/ Postnasal Drip
• Dry up / stop the mucus:
(1) Dexbrompheniramine
(2) Decongestants
(3) Steroid nose sprays
(4) Antihistamine nose sprays
(5) Ipratropium (0.06%) nose spray
• Liquify the mucus:
(1) Sinus rinse
(2) Guaiafenesin
Treat the cause, use combinations!
How important is sinus imaging
• Consider in cough patients with postnasal
drip unresponsive to treatment
• Consider in cough patients who are
smokers
• Sinus XRay vs Sinus CT
• Sinus: Limited vs Full CT
Sinusitis in children
• Paranasal sinuses
– Maxillary and Ethmoid sinuses are present at
birth
– Sphenoid and Frontal sinuses are
radiographically present by 5-6 yrs of age
Reflux Disease
• Cough and hoarseness are the major complaints.
• Heartburn, sour taste and regurgitation are unusual.
• Silent reflux in 50-75% cases
• H2-blocker alone may fail
• Remember: Diet, Weight reduction, etc…
The Clinical History of Reflux
• Diurnal variation– Cough on lying down - positional
– Decrease when asleep
– Wakes without cough
– Cough on rising
• With food– The act of eating
– Types of food
– Post prandial
Laryngopharyngeal Reflux
• Increasing incidence
• Hoarse voice
• Transient aphonia
• Globus (sensation of a lump in the throat)
• Persistent throat clearing
• Tickle in the throat or sticky sensation
Laryngopharyngeal Reflux
Pseudosulcus vocalis
Posterior commissure hypertrophy
Vocal fold edema
Ventricular obliteration
Koufman Score
If RFS >7, 95% PPV for LPR
Reflux Tests
• Laryngoscopy
• 24-hour Esophageal pH monitor
• Multichannel Intraluminal Impedance and manometry
• Bravo pH Probe
• EGD
• Barium Swallow
• Motility studies
• Aeriflux
24-hour esophageal pH monitoring
• Positive predictive value: 89%
• Negative predictive value: <100%
• Inconvenient for patients, ? interpretation of results in the diagnosis of cough
• Explore a temporal relationship between reflux and cough (keep a cough diary)
• Useful if therapeutic trial fails
Airway pH Measurement
• Aeriflux measures acid in the airway not in the
esophagus
• Collection system condenses exhaled breath
• Volatile acids from the airway are captured during this
condensation process
• If acids are exhaled at a time when coughing is
occurring, a direct relationship between reflux and cough
is established
Sleep apnea and GERD
• The phreno-esophageal ligament (PEL) connects the diaphragm to the LES.
• During the sleep apnea syndrome, there is increased respiratory effort by the diaphragm.
• This extra effort is transmitted to the LES by the PEL.
• This further leads to opening of LES and possibly reflux.
Is GERD as a cause of chronic
cough being overdiagnosed?
• Depending on flexible laryngoscopy to detect changes of LPR can lead to over-and under-diagnosis
• Acid versus non-acid reflux
• Role of barium swallow
• Role of EGD
• Multichannel Intraluminal Impedance and manometry
Reflux Disease- Management
• Diet and Lifestyle
• Weight reduction
• Treating sleep apnea
• H2 blockers
• PPI
• Properistaltic agents
• Avoid excessive exercise
Methacholine Challenge test
In a setting of adult chronic cough patients:
• Positive predictive value: 60-88%
• Negative predictive value: 100%
Asthma and Cough
• Bronchial inflammation causes vagal stimulation
• Asthma (and eosinophilic inflammation) ruled
out if MCT negative and no response to
prednisone 30 mg po qd for 2 weeks
• Consider adding leukotriene modifiers if
inadequate/no response to inhaled steroids
Asthma Eosinophilic
bronchitis
• Sputum eosinophilia
• Airway hyperresponsiveness
• Treatment is inhaled or oral steroids
• Sputum eosinophilia
• No airway hyperresponsiveness
• Treatment is inhaled or oral steroids
• Natural history unclear
• Initially reported in 1989
Eosinophilic bronchitis
How can physiologic alterations in
severe asthma promote reflux?
• Increase in transient LES relaxation
• LES hypotonia
• Esophageal dysmotility (due to autonomic
dysfunction in asthma)
• Asthma meds can increase LES dysfunction
(theophylline, oral beta agonists)
• Hyperinflation in asthma reduces crural
diaphragmatic support to the LES
Psychogenic/Habit cough
• More common in the childhood/teenage years
• Characteristically does not occur while sleeping
• Honking or barking cough may be diagnostically
helpful in kids, not in adults
• Rule out all possible causes first
• Treatment: Patient education, breathing
exercises
Irwin RS Chest 1998;114(suppl): 133S-181S
J Commun Disord 1988 Sep;21(5):393-400
How common is lung cancer in
chronic cough?
• Very rare (0 to 2%)
• CXR has a negative predictive value of
>95%, and a positive predictive value of
30 to 40%
Chest 1998;114(2):133s-181s
Treatment of Unexplained Cough
• Rule out all possible causes first
• Team approach- Allergy, Pulmonology, Otolaryngology, Gastroenterology, Speech Therapy, Behavioral Counseling
• Think outside the box- use lidocaine via nebulizer, nedocromil inhaler, baclofen, neurontin, Bromfenex, manage chronic pain, weight reduction, rule out sleep apnea
• Don’t give up too soon!
Work-up for chronic cough
• CXR
• Limited sinus CT
• Spirometry
• Methacholine challenge test
• Allergy skin tests
• Environmental control
• R/O occupational exposures
• Chest CT
• Neck CT
• Rhinolaryngoscopy
• Bronchoscopy
• 24-hour esophageal pH monitor
• EGD
• Barium swallow, etc.
Individualize the approach
Be cost-effective
Tips About Work-up
• Sinus XR can be false negative (consider limited CT sinus)
• CXR can be false negative (10%) in Interstitial Lung Disease (consider HRCT Chest)
• OK to get second opinion from another Radiologist if in doubt
• Just because a patient has seen ENT, don’t assume sinusitis is ruled out!
Therapeutic trials: When to expect a
response?
• Smoking cessation: up to 4 weeks
• ACE-inhibitor discontinuation: up to 4 weeks
• Postnasal drip syndromes: up to 2-3 weeks
• Asthma: up to 6-8 weeks
• GERD: up to 8-12 weeks
• Eosinophilic bronchitis: up to 3-4 weeks
Don’t give up too soon
What is the clinical utility of
flexible bronchoscopy
• Adds little to the diagnosis of chronic cough in
the context of normal CXR or HRCT Chest
• Useful to detect and assess endobronchial
lesions (tumors, foreign bodies)
• Always get a HRCT Chest before bronchoscopy
• If you are checking a HRCT Chest: include the
neck
Barnes TW, et al. Chest 2004;126:268-272
Cough Suppressant Therapy
Site of action Drugs
Mucocilliary clearance Guaiafenesin, Ipratropium
(Not tiotropium/spiriva)
Afferent limb of cough
reflex
Moguisteine,
Levodropropizine (Not
available in the US)
Centrally acting Codeine,
Dextromethorphan
Efferent limb Baclofen (GABA agonist)
reflux cough resistant for
PPI and ACEI cough
When to use cough suppressants
and expectorants?
Very rarely
• Some available over the counter
• Incurable lung cancer
• Codine, dextromethorphan (Delsym), TessalonPerles, Tussionex
• Guaiafenesin: ? decreases cough receptor sensitivity, loosens the mucus. Trial with 1200 mg twice daily for adults.
Nonpharmacologic Airway
Clearance Therapies
• Assisted techniques - Chest physiotherapy,
manually assisted cough, autogenic drainage,
respiratory muscle strength training
• Devices - Positive Expiratory Pressure,
Oscillatory Devices, Mechanical insufflation-
exsufflation, electrical stimulation of respiratory
muscles
• Beneficial in the short-term; long-term efficacy
and outcomes are unknown
Zebras to watch for
• “Clinically silent” suppurative airway disease
• Congestive heart failure
• Cancer: bronchogenic, esophageal, metastasis
• Cystic fibrosis
• Interstitial lung disease
• Foreign bodies
• Pneumonia, recurrent aspiration, pharyngeal dysfunction
• Sarcoidosis
Zebras to watch for, continued
• Pressure from an intrathoracic mass
• Primary ciliary dyskinesia (infertility)
• Lingual thyroid (hypothyroidism)
• Sleep apnea
• Vocal cord dysfunction (can cause post-viral cough)
• Pulmonary tuberculosis
• Bronchiectasis
• Chronic tonsillar enlargement
Vocal Cord Dysfunction
Vocal Cord Dysfunction
• Paradoxical vocal cord motion (PVCM)– Episodic laryngeal dyskinesia, VCM
– Vocal cord adduction during inspiration/expiration causing a functional extrathoracic airway obstruction.
– Symptoms include: wheeze, cough, dyspnea
– More common than is appreciated, diagnosis frequently not considered.
– Often confused with asthma and misdiagnosed.
– Much morbidity caused from misdiagnosis.• Newman et al studied 95 patients with proven PVCM
• Asthma was misdiagnosed an avg. 4.8 years, 28% intubated
Prevalence• General population is unknown.
– O’Connel et al, 164 patients
– Up to 20% of females who underwent rhinolaryngoscopy for any reason had PVCM.
• National Jewish Center, 1994, multiple patients diagnosed with refractory asthma:
– 10% had PVCM alone.
– 30% had PVCM with coexistent asthma.
• Patients diagnosed with PVCM:
– 56% had coexistent asthma.
• Because PVCM is common among asthmatics and presents with symptoms similar to those seen in patients with only asthma, it is commonly overlooked and not included in the differential.
Demographics
• In children under age 18:
– 2 studies at different institutions found:
• Average presenting age: 14.6 (range 9.0 – 18.0)
• 82-86% of patients female.
• Similarities among patients included: organized
sports, social stressors, exercised-induced
symptoms.
– Powell et al found strong association with GERD.
• Laryngospasm likely secondary to reflux irritation
but cause- effect relationship has not yet been
established
Demographics cont’d
• All age groups:– Average age at diagnosis 30 years (range 22-34)
– 70-98% of patients were female, Caucasian
• Documented psychological risk factors:– Medical profession, overweight, stress, anxiety,
childhood abuse, psychiatric illness.
– Increased incidence during wartime.
• Documented physiological risk factors:– Asthma, brainstem abnormalities, CF, GERD
Clinical Presentation
• Wide variety of symptoms including: – Cough
– Inspiratory/expiratory wheeze
– Dyspnea with/without exertion
– Stridor
– Hoarseness
– Chest tightness
– Reflux
• Study evaluating 90 patients with PVCM– Cough was the most common symptom - up to 77%
Clinical Presentation cont’d
• History significant for frequent, episodic attacks leading to SOB and multiple ER visits.
• Previous diagnoses include asthma, refractory asthma, exercise-induced bronchospasm, COPD, anaphylaxis.
• Children with PVCM have increased incidence of anxiety disorder compared to asthmatics.– Anxiety precedes respiratory symptoms in PVCM
– Anxiety follows respiratory symptoms in asthmatics.
Physical Exam
• Classical finding on laryngoscopic exam is inspiratory anterior vocal cord closure with posterior chinking.
• This obstruction decreases laminar airflow through the glottis and produces an inspiratory wheeze or stridorous sound similar to that heard in asthmatics.
• Differs from paralysis:– PVCM show normal cord movement during
phonation.
• Differs from laryngospasm: – Laryngospasm shows adduction throughout the
entire cord length without posterior chinking.
Posterior chinking
Other Physical Exam Findings
• Wheezing originates over the larynx and is less evident over the rest of the lung fields.
• Tachypnea with neck extension and constant contraction of the anterior neck muscles.
• Patients with or without concurrent asthma are often hypoxic and therefore may appear cyanotic during exacerbations.
• Spirometry with flow-volume loops have been used to support the diagnosis of PVCM in symptomatic patients.
• Flow-volume loops of patients with PVCM often show flattening of the inspiratory curve, or a decrease in maximal inspiratory flow during acute attacks, and are normal while asymptomatic.
PCVM
PFT studies cont’d
• Inspiratory blunting is sensitive for symptomatic patients with PVCM but is not specific for VCD and may be produced by most types of extrathoracic airway obstruction.
• Parker et al evaluated 26 patients with PVCM– exercise flow-volume loops indicated the upper
airway as a cause for symptoms in 74%
– 62% showed inspiratory flow limitation
• Primary use of PFT’s is to eliminate asthma from the differential diagnosis.
PFT studies cont’d
• Expiratory adduction and obstruction has been
shown by laryngoscopy in these patients without
evidence of expiratory flow-volume abnormalities.
– Mechanism unknown, pursed-lip exhalation
suspected
• Elevates soft palate to posterior nasopharyngeal wall
• Closes nasopharyngeal airway, increases resistance
• Creates sufficient back pressure to open vocal cords
and therefore shows no expiratory flow loop defect
Diagnosis• Difficult due to its episodic nature and presentation.
• Criteria for diagnosis:– Laryngoscopic confirmed adduction of vocal cords during
inspiration, early expiration, or both inspiration and expiration with evidence of posterior glottic chinking.
• adduction occurring during only the last half of expiration is not pathologic
– PVCM cannot be ruled out when asymptomatic.• if the patient is asymptomatic, negative laryngoscopic findings do
not exclude the diagnosis
– Absence of gagging or coughing during laryngoscopy• must not confuse PVCM with vocal cord motion produced by a
laryngoscope induced gag reflex
Treatment of VCD
• Acute treatment
– Heliox 70/30
– CPAP
– IPPV
– Benzodiazepines
– Panting exercises
– Reassurance
• Long term management
– Biofeedback training
– Supportive
psychotherapy
– Speech therapy
– Hypnotherapy
– Panting exercises