alt.support.asthma FAQ: Asthma -- General Information
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Archive-name: medicine/asthma/general-info
URL: http://www.radix.net/~mwg/asthma-gen.html
Posting-Frequency: monthly
Last-modified: 17 September 2000
Original-author: Patricia Wrean
Version: 5.3
alt.support.asthma FAQ: Asthma -- General Information
======================================================
Introduction:
------------
Welcome to alt.support.asthma! This newsgroup provides a forum for
the discussion of asthma, its symptoms, causes, and forms of treatment.
Please note that postings to alt.support.asthma are intended to be
for discussion purposes only and are in no way to be construed as
medical advice. Asthma is a serious medical condition requiring
direct supervision by a physician.
This FAQ attempts to answer the most frequently asked questions about
asthma on the newsgroup alt.support.asthma. It was compiled by Patricia
Wrean and is currently maintained by Marie
Goldenberg . The Asthma Medications FAQ is also posted
monthly as a companion to this one. For information about allergies,
please see the alt.support.asthma FAQ: Allergies -- General Information
(still under construction), and its companion posting, the Allergy
Medications FAQ.
Please be aware that the information in this FAQ is intended for
educational purposes only and should not be used as a substitute
for consulting with a doctor. Most of the contributors are not
health care professionals; this FAQ is a collection of personal
experiences, suggestions, and practical information. Please remember
when reading this that every asthmatic responds differently; what is
true for some asthmatics may or may not be true for you. Although
every effort is made to keep this information accurate, this FAQ
should not be used as an authoritative reference.
Comments, additions, and corrections are requested; if you do not wish
your name to be included in the contributors list, please state that
explicitly when contributing. I will accept additions upon my own
judgement -- I'll warn you right now that I'm a confirmed skeptic and am
not a great believer in alternative medicine. All unattributed portions
are my own contributions or those of the original maintainer, Patricia
Wrean .
+ = added since last version
& = updated/corrected since last version
======================================================================
Table of Contents:
-----------------
General Information:
0.0 Changes since the last version
1.0 What is asthma?
1.0.1 What is chronic asthmatic bronchitis?
1.0.2 What is status asthmaticus?
1.0.3 What is anaphylactic shock?
1.0.4 What is COPD?
1.0.5 What is emphysema?
1.0.6 What is bronchitis?
1.0.7 What is pneumonia?
1.0.8 What is cystic fibrosis?
1.1 What is an asthma attack?
1.1.1 What is wheezing?
1.1.2 Do all asthmatics wheeze?
1.1.3 What is "coughing asthma"?
1.1.4 Is asthma hereditary?
1.2 How is asthma diagnosed?
1.2.1 What is a spirometer?
1.2.2 What is a peak flow meter?
1.3 How is asthma normally treated?
1.3.1 How is an acute asthma attack treated?
1.4 What are the most common triggers of asthma?
1.4.1 What is intrinsic/extrinsic asthma?
1.4.2 Can gastric reflux trigger asthma?
1.4.3 What is occupational asthma?
1.5 Asthma and Pregnancy
Medications:
2.0 What are the major classes of asthma medications?
2.1 What are the names of the various asthma medications?
2.1.1 Are salbutamol and albuterol the same drug?
2.1.2 Can albuterol be taken while taking salmeterol?
2.2 Are some asthma drugs banned in athletic competitions?
2.3 What kinds of inhalers are there?
2.3.1 Do inhaler propellants bother some asthmatics?
2.3.2 What is a spacer? What is a holding chamber?
2.3.3 What is "thrush mouth" and how can I avoid it?
2.3.4 Is Fisons still making the Intal Spinhaler?
2.3.5 What's the difference between Spinhalers and Rotahalers?
2.3.6 Why are so many asthma drugs taken via inhaler?
2.3.7 How can I tell when my MDI is empty?
2.3.8 Are my aerosol inhalers going to disappear?
2.4 What kinds of tablets are there?
2.4.1 Why do I need a blood test when taking theophylline?
2.4.2 Why are combination pills not commonly prescribed?
2.5 What is a nebulizer?
2.6 What medications should asthmatics be careful about taking?
2.6.1 What about corticosteroids and chicken pox?
Miscellaneous:
3.0 What resources are there for asthmatics?
3.1 Where can I get the latest copy of the FAQs?
3.2 What is an FAQ, anyway? What is a Usenet newsgroup?
+ 3.3 How about some other WWW links?
List of Contributors
References
Disclaimer
======================================================================
0.0 Changes since the last version
-----------------------------------
September 17, 2000
------------------
Asthma Gen: Added 3.3 WWW links section
Asthma Gen: Added reference to Living Well With Asthma book
Asthma Gen: Added reference to The Doser (inhaler counter) in section 2.3.7
Asthma Med: Added reference to Advair (salmeterol / fluticasone)
Asthma Med: Added reference to Bambec (bambuterol)
Asthma Med: Added reference to Combivent (ipratropium / salbutamol)
Asthma Med: Noted that Bronkaid and Isuprel appear to have been
discontinued in Canada
Asthma Med: Added reference to Xopenex (levalbuterol)
Asthma Med: Added reference to Oxeze (formoterol) turbuhaler
Asthma Med: Added reference to Pulmicort neb soln available in US
September 17, 1998
------------------
Asthma Med: Added note that Foradil (formoterol) now available in Canada
February 17, 1998
-----------------
Asthma Med: Added Serevent Diskus, Flovent Rotahaler, Pulmicort,
Airomir, Tilade nebulizer solution, and Singulair
(newly approved medications)
Asthma Med: Added note that Medihaler-Epi has been discontinued
Allergy Med: Added note that Seldane has been discontinued
Allergy Med: Added Nasonex (newly approved medication)
Asthma General: Added section 1.4.3, Occupational asthma
December 6, 1997
----------------
Asthma General: Split web version of FAQ document into multiple-page
format.
August 17, 1997
---------------
Asthma General: Added section 1.5, "Pregnancy and Asthma"
Asthma General: Added reference to new version of NHLBI report
Asthma General: Added reference to Adams book
Asthma General: Correct reference to Gershwin to reflect 2nd edition
June 17, 1997
-------------
Asthma General: Correct publication information on "Children With
Asthma" by Dr. Plaut
Asthma General: Added links to archived version of Allergy
Medication FAQ
May 17, 1997
------------
Asthma Med: Added note that Nasalcrom now Over-The-Counter (OTC) in US.
Asthma Med: Added Zyflo to Leukotriene Receptor Inhibitor section
Asthma Med: Added Proventil HFA MDI
Asthma General: Added discussion of phaseout of CFC
(chlorofluorocarbon) MDIs
Asthma General: removed comment that "both spinhaler and rotahaler are
available in the US" (the spinhaler is not available in the US)
1.0 What is asthma?
--------------------
Asthma is best described by its technical name: Reversible
Obstructive Airway Disease (ROAD). In other words, asthma
is a condition in which the airways of the lungs become
either narrowed or completely blocked, impeding normal
breathing. However, in asthma, this obstruction of the lungs
is reversible, either spontaneously or with medication.
Quickly reviewing the structure of the lung: air reaches the
lung by passing through the windpipe (trachea), which divides
into two large tubes (bronchi), one for each lung. Each
bronchi further divides into many little tubes (bronchioles),
which eventually lead to tiny air sacs (alveoli), in which
oxygen from the air is transferred to the bloodstream, and
carbon dioxide from the bloodstream is transferred to the air.
Asthma involves only the airways (bronchi and bronchioles),
and not the air sacs. The airways are cleaned by trapping
stray particles in a thin layer of mucus which covers the surface
of the airways. This mucus is produced by glands inside the
lung, and is constantly being renewed. The mucus is then
either coughed up or swept up to the windpipe (trachea) by
cilia, tiny hairs on the lining of the airways. Once the
mucus reaches the throat, it can again be coughed up or,
alternatively, swallowed.
Although everyone's airways have the potential for constricting
in response to allergens or irritants, the asthmatic's airways
are oversensitive, or hyperreactive. In response to stimuli,
the airways may become obstructed by one of the following:
- constriction of the muscles surrounding the airway;
- inflammation and swelling of the airway; or
- increased mucus production which clogs the airway.
Once the airways have become obstructed, it takes more effort
to force air through them, so that breathing becomes laboured.
This forcing of air through constricted airways can make a
whistling or rattling sound, called wheezing. Irritation of
the airways by excessive mucus may also provoke coughing.
Because exhaling through the obstructed airways is difficult,
too much stale air remains in the lungs after each breath.
This decreases the amount of fresh air which can be taken in
with each new breath, so not only is there less oxygen
available for the whole body, but more importantly, the high
concentration of carbon dioxide in the lungs causes the blood
supply to become acidic. This acidity in the blood may rise
to toxic levels if the asthma remains untreated.
1.0.1 What is chronic asthmatic bronchitis?
--------------------------------------------
Chronic asthmatic bronchitis is the condition in which the
airways in the lungs are obstructed due to both persistent
asthma and chronic bronchitis (see sections 1.0 and 1.0.6).
People with this disease generally also have a persistent
cough which brings up mucus. Chronic asthmatic bronchitis
which also involves emphysema is usually classified under
the more general category of COPD.
1.0.2 What is status asthmaticus?
----------------------------------
Status asthmaticus is defined as a severe asthma attack that
fails to respond to routine treatment, such as inhaled
bronchodilators, injected epinephrine (adrenalin), or
intravenous theophylline.
1.0.3 What is anaphylactic shock?
----------------------------------
Anaphylactic shock is defined as a severe and potentially
life-threatening allergic reaction throughout the entire
body. It occurs when an allergen, instead of provoking a
localized reaction, enters the bloodstream and circulates
through the entire body, causing a systemic reaction.
(There may also be an intrinsic trigger, as some cases of
exercise-induced anaphylaxis have been reported.)
The symptoms of anaphylactic shock begin with a rapid
heartrate, flushing, swelling of the throat, nausea, coughing,
and chest tightness. Severe wheezing (asthma), cramping, and
a rapid drop in blood pressure follow, which may lead to cardiac
arrest. Hives and vomiting are also common features. The
treatment for anaphylaxis is intravenous epinephrine (adrenalin),
with antihistamines and steroids also being used in selected
cases. Aminophylline may also be given for pronounced asthmatic
reactions that do not respond to epinephrine.
1.0.4 What is COPD?
--------------------
COPD is chronic obstructive pulmonary disease, also known as
either COAD, for chronic obstructive airway disease, or COLD,
for chronic obstructive lung disease. COPD is a disease in
which the airways are obstructed due to a combination of
asthma, emphysema, and chronic bronchitis. The 1987 Merck
Manual notes that "the term COPD was introduced because these
conditions often coexist, and it may be difficult in an
individual case to decide which is the major one producing
the obstruction."
[Maintainer's note: the entries for COPD, emphysema, bronchitis,
pneumonia, and cystic fibrosis have been included because of
common confusion between the various diseases which can affect
the lungs.]
1.0.5 What is emphysema?
-------------------------
Emphysema is the disease in which the air sacs themselves, rather
than the airways, are either damaged or destroyed. This is an
irreversible condition, leading to poor exchange of oxygen and
carbon dioxide between the air in the lungs and the bloodstream.
1.0.6 What is bronchitis?
-------------------------
Bronchitis is an inflammation of the bronchi, the large airways
inside the lungs. (Bronchiolitis is the inflammation of the
bronchioles, the small airways.) This inflammation often leads
to increased mucus production in the airways.
Bronchitis is generally caused either by a virus or by exposure
to irritants such as dust, fumes, or cigarette smoke. If caused
by a virus, the bronchitis will likely be only temporary. In
the case of prolonged exposure to irritants, particularly
cigarette smoking, if there is permanent damage to the bronchi,
bronchitis may become chronic.
1.0.7 What is pneumonia?
-------------------------
Pneumonia is an infection of the lung tissue. In adults, it is
generally caused by bacterial infections, though viruses, fungi,
and protozoa may also be culprits. The latter microorganisms
have become very common as causes of pneumonia in immunosuppressed
persons, such as those with HIV infection. However, for those
with chronic illnesses, especially cardiac or respiratory
diseases, or those at increased risk for pneumonia, there is a
pneumococcal pneumonia vaccination available as a preventive
measure for the most common of these bacterial infections,
streptococcus pneumoniae. In children, pneumonia is most
commonly caused by viruses.
1.0.8 What is cystic fibrosis?
-------------------------------
Cystic fibrosis is a disease in which excessive amounts of
unusually thick mucus are produced throughout the body.
Because this mucus production also occurs in the lungs,
people with cystic fibrosis are extraordinarily prone to
bacterial infections which result in progressive lung damage.
Cystic fibrosis can be diagnosed by a "sweat test" as people
with cystic fibrosis have elevated chloride levels in their
perspiration. This condition often resembles asthma in
children.
1.1 What is an asthma attack?
------------------------------
An asthma attack, also known as an asthma episode or flare,
is any shortness of breath which interrupts the asthmatic's
well-being and requires either medication or some other form of
intervention for the asthmatic to breathe normally again.
1.1.1 What is wheezing?
------------------------
Wheezing is the whistling or rattling sound that occurs when
air flows through obstructed airways. At the start of an
asthma attack, wheezing usually only occurs while exhaling, or
breathing out, but as the attack progresses, wheezing may
then be heard both while inhaling and exhaling. If after
the attack progresses further, the asthmatic then stops wheezing,
this may indicate that many bronchioles (small airways) have
become completely blocked, which is a very serious condition.
1.1.2 Do all asthmatics wheeze?
--------------------------------
No, not all asthmatics wheeze. Although wheezing is extremely
common in asthmatics, in _All About Asthma_, Dr. Paul says,
"It is important to note that not all asthmatic symptoms need be
present for one to experience an asthma attack. For instance,
not all asthmatics wheeze. And sometimes wheezing is so slight,
it can only be heard with a stethoscope. With some asthmatics,
coughing is the only symptom present." Similarly, in _Children
with Asthma_, Dr. Plaut states that children with chronic coughs
"may have asthma even though no wheezing is present." He
diagnoses such children with asthma if their peak flow improves
when given an inhaled bronchodilator.
1.1.3 What is "coughing asthma"?
---------------------------------
In _Children with Asthma_, Dr. Plaut defines "coughing asthma"
as "a form of asthma in which coughing is the only symptom and
there is no abnormality in any lung function test." This
condition is also known as "cough variant asthma." Coughing
asthma often improves when standard asthma medications are
taken.
1.1.4 Is asthma hereditary?
----------------------------
No, asthma itself is not hereditary, but there does seem to be
a hereditary component to the tendency to develop asthma. In
_All About Asthma_, Dr. Paul states that if neither parent has
asthma, the chances of each of their children having asthma are
less than 10%. When one parent has asthma, the chances rise to
25%, and when both parents have asthma, the chances climb to 50%.
(Actually, there is considerable disagreement among my sources
as to the exact numbers, but all agree that the chances climb
dramatically if one or both parents have asthma.)
Similarly, if one or both parents have allergies, the chances
of each of their children having allergies are 35% and 65%,
respectively, compared to a less than 10% chance if neither
parent has allergies.
However, Dr. Paul cautions that "children don't inherit asthma
itself, but the tendency to develop it." Whether or not an
individual develops asthma is also influenced by their exposure
to various other factors such as infections, irritants, and
allergens.
1.2 How is asthma diagnosed?
-----------------------------
Asthma is diagnosed based on a physical examination, personal
history, and lung function tests. The physical examination looks
for typical asthma symptoms such as wheezing or coughing, and the
personal history provides additional clues such as allergies or a
familial tendency towards asthma. Although lung function tests
have not always been used for diagnosis in the past, the NHLBI
Guidelines for the Diagnosis and Management of Asthma state that
"Pulmonary function studies are essential for diagnosing asthma
and for assessing the severity of asthma in order to make
appropriate therapeutic recommendations. The use of objective
measures of lung function is particularly important because
subjective measures, such as patient symptom reports and
physicians' physical examination findings, often do not correlate
with the variability and severity of airflow obstruction."
Lung function tests may be as simple as measuring peak flow with
a peak flow meter, or using a simple spirometer, or may involve
a battery of spirometry tests in a pulmonary function lab.
1.2.1 What is a spirometer?
----------------------------
A spirometer is a machine for testing lung function that you
breathe in and out of through a hose attached to a mouthpiece.
You are usually given nose clips so that all the air you breathe
goes through the machine. One I've been tested on had a little
expanding tank surrounded by water into which the air goes, and
I could see the top rising and falling as I breathed out and in.
It can measure a fair number of characteristics of your lungs,
including FVC, FEV1, and PEPR. FVC, or forced vital capacity,
is the amount of air that you can exhale forcefully after taking
a deep breath. FEV1, or forced expiratory volume in one second,
is the amount of air that you can be exhale in one second.
Peak flow, or PEPR, is described in section 1.2.2.
The sophisticated spirometers I've seen have a PC attached, and
have neat little curves generated with each breath, which
apparently have characteristic shapes for different respiratory
diseases.
There is a slightly less sophisticated machine that I've blown
into, and I'm not sure if this is also classed as a spirometer or
not, but you take a deep breath and blow into it, much like a
peak flow meter, except that it draws a little graph of how much
volume you've blown out, and I'd imagine that you can get the
FVC and FEV1 off this graph.
For more information, I recommend the book by Drs. Haas,
_The Essential Asthma Book_, which goes into more detail about
the various things you can find out from spirometry.
1.2.2 What is a peak flow meter?
---------------------------------
A peak flow meter is a little plastic device which you blow hard
into, after having taken a deep breath. It records the rate at
which you've blown into it in litres exhaled per minute (L/min)
-- this is called the peak expiratory flow rate (PEF or PEFR).
The meter is essentially a cylinder with a mouthpiece at one end,
a place for the air to escape at the other end, and a calibrated
meter along the side. When you blow into it, a marker is pushed
along the scale and comes to rest at a point which indicates your
PEF. Since you want to measure your maximum peak flow, it is
important to take a deep breath and blow as hard and as fast as
you can. Many asthmatics find that their maximum peak flow provides
a good objective measure of how their asthma is doing, so peak flow
meters now are used extensively for self-monitoring of asthma, and
also for monitoring the effectiveness of asthma medications.
1.3 How is asthma normally treated?
------------------------------------
Treatment of mild asthma usually tries to relieve occasional
symptoms as they occur by use of short-acting, inhaled
bronchodilators. Treatment of moderate or severe asthma,
however, attempts to alleviate both the constriction and
inflammation of the airways, through the use of both
bronchodilators and anti-inflammatories. Bronchodilators are
drugs which open up or dilate the constricted airways, while
drugs aimed at reducing inflammation of the airways are called
anti-inflammatories.
Taking anti-inflammatory drugs (usually inhaled corticosteroids)
daily for moderate to severe asthma is a relatively new approach
to treating asthma. The idea behind it is that if the underlying
inflammation of the airways is reduced, the bronchi may become
less hyperreactive, making future attacks less likely. Such
anti-inflammatory therapy, however, must be taken regularly in
order to be effective.
For asthma which is strongly triggered by allergies, allergen
avoidance can often greatly reduce the amount of medication
needed to control the asthma. Taking anti-allergic medications
or taking shots for allergy desensitization are other
alternatives. For more information about allergen avoidance
and allergies in general, please see the alt.support.asthma FAQ:
Allergies -- General Information (still under construction).
1.3.1 How is an acute asthma attack treated?
---------------------------------------------
An acute asthma attack is usually treated with bronchodilators
to reduce the constriction of the airways. Intravenous adrenalin
and theophylline are often given in emergency rooms for this
purpose, if short-acting bronchodilators given by nebulizer
haven't sufficiently controlled the attack.
Once the acute attack is over, anti-inflammatories may be used to
reduce the inflammation of the airways. Inhaled steroids are
usually the first choice, but for a sufficiently severe attack,
oral steroids such as prednisone may also be given.
1.4 What are the most common triggers of asthma?
--------------------------------------------
The most common triggers of asthma are:
- viral respiratory infections, such as influenza (the flu)
or bronchitis;
- bacterial infections, including sinus infections;
- allergic rhinitis;
- irritants, such as pollution, cigarette smoke, perfumes,
dust, or chemicals;
- sudden changes in either temperature or humidity, especially
exposure to cold air;
- allergens, for people with allergies;
- emotional upsets, such as stress; and
- exercise.
1.4.1 What is intrinsic/extrinsic asthma?
------------------------------------------
Intrinsic and extrinsic asthma are outdated terms which have now
been replaced by terms related to the asthma trigger, since the
inflammatory response of the airways is the same independent of
the cause of the asthma. What was known as extrinsic asthma is
now called allergic asthma, while asthma triggered by non-allergic
factors, formerly called intrinsic asthma, is separated into such
categories as exercise-induced asthma and occupational (chemical-
induced) asthma.
1.4.2 Can gastric reflux trigger asthma?
----------------------------------------
Yes, gastric reflux can act as an irritant which triggers
asthma. Reflux, properly known as gastroesophageal reflux,
occurs when the liquids in the stomach pass up the esophagus,
or feeding tube. Because these liquids are usually highly
acidic, they can irritate and inflame the esophagus, and
also the airways of the lung, should any of this liquid be
aspirated. This irritation can trigger an asthma attack.
Asthma flares caused by reflux are more common at night,
for it is easier for material to pass up the esophagus when
one is lying down. Some simple treatments to prevent reflux
include raising the head of the bed, not eating close to
bedtime, or using either antacids or medications such as
ranitidine (Zantac) which reduce the amount of acid produced
by the stomach.
Contributed by: Betty Bridges bcb56@ix.netcom.com
1.4.3 What is Occupational Asthma?
-----------------------------------
Occupational Asthma is asthma that is caused by sensitization from
exposures in the workplace. Asthmatics whose asthma is exacerbated by
exposures in the workplace would not be classified as having
occupational asthma.
There are over 200 substances that have been documented as causing
occupational asthma, but there are probably more that have not been
recognized. The substances that are known to cause occupational asthma
can be divided into two main categories.
High molecular weight proteins of animal or plant origins are common
causes. Things like animal dander, flour proteins, and animal scales
are frequently causes of occupational asthma. These same things are
also common causes of non-occupational asthma. These are usually
IgE-mediated responses.
Low molecular weight chemicals that have the ability to bind with
proteins or act as haptans are causes of occupational asthma. There
may be other mechanisms involved besides the classic IgE-mediated
responses as not all those that are sensitized have specific
antibody production. Reactions may have reflex, inflammatory,
pharmacological, or immunologic pathways or a combination of several.
Often occupational asthma is difficult to diagnosis. There are may be
immediate, late, or biphasic reactions. In late reactions the symptoms
may not occur until away from the work place. Frequently the asthma
worsens as the workweek progresses and improves over the weekend.
Treatment for occupational asthma is basically the same as any other
asthma with a few very important exceptions. For those that have
chemically induced asthma from sensitization to that chemical;
avoidance of the trigger is essential. While steroids and other
medications are helpful in treating the symptoms, they do not
prevent the underlying sensitivity from increasing.
Once sensitized to a substance, some react to minute amounts. Levels
below current TLV levels still trigger reactions. For a sensitized
individual any exposure can cause symptoms.
Continued exposure to the triggering chemical can cause permanent lung
damage, chronic asthmatic conditions, and even death. Medication
should never be used to allow the worker to continue to work in an
environment where there is exposure to the triggering substance. Early
recognition and removal from exposure is essential in preventing long
term disability from asthma.
Chemically induced asthma can occur both in the workplace and outside
of the workplace. There are many exposures outside of the workplace
that there are exposures to chemicals that can induce asthma. Most
physicians are not familiar with this type of asthma. For anyone that
has chemically induced asthma, avoidance of the trigger is essential.
1.5 Asthma and Pregnancy
-------------------------
Many people have posted to ask about whether it is safe to become
pregnant while suffering from asthma, and in particular whether it is
safe to use their asthma medications while pregnant.
The general consensus (from the doctors I have consulted) is that
asthmatics can safely become pregnant without undue worry about whether
the mother and the baby will be all right. Most doctors talk about a
"rule of 1/3" by which they mean that roughly 1/3 of all asthmatics get
better while pregnant, 1/3 stay the same, and 1/3 find their asthma is
aggravated (I improved with one pregnancy, and stayed the same with the
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