Pulmonary
EmboliIntroduction: Emboli are blood clots. They
usually form in leg veins or in pelvic veins. If you would like a quick primer
on what thrombosis is all about,
click on this link and click on "All About DVT". Clots happen because
a person is particularly vulnerable from a constitutional point of view or because
there is a time period such as following surgery, where the blood is thicker and
clots happen easier. Also, certain hormone changes can predispose the person
to blood clots. When clots
occur in leg veins or pelvic veins, there is a risk that the clots
grow in length, finally break off and migrate into the right heart. There they
tend to break up and move on into the arteries of the lungs (see
how this affects the lung). This can lead to acute symptoms
and in about 10% of the cases is severe enough to close off the circulation to
at least a part of the lung (if not all of the lung), which is called pulmonary
infarction. When 608clots from the veins in the legs break off and
migrate into the lungs pulmonary emboli result. In about
65% this affects both lungs. Due to anatomical differences there is a slight blood
circulation advantage to the right lung, so the remainder of the clots, when only
one lung is affected, occurs in 25% in the right lung and in 10% in the left lung.
Signs and symptoms: The onset of pulmonary emboli
is usually very acute. There are a variety of symptoms that occur simultaneously.
The most striking symptom is an air hunger and rapid deep breathing (dyspnea).
If the clots are massive, the patient may get into shock and become unconscious
or may even die. However, this happens only in 1 to 5%. Here are some of the most
common symptoms of blood clots. Most of the time there is a slower onset or there
is only a partial blockage of the pulmonary arteries, but the patient still needs
to be rushed into a hospital by ambulance as quickly as possible. Heparin, which
is an anticoagulant medication needs to be started right away to prevent further
clot formation. Other clot dissolving medication is also started to get a rapid
improvement of the condition as soon as possible. With clots that lead to infarction
at the surface of the lung there will be a friction rub that the doctor may hear
using the stethoscope and the patient feels pain with every breath due to pleuritic
pain. Hemoptysis (coughing up blood or blood stained phlegm) can be another sign
as well as wheezing. The patient is usually extremely anxious and restless, which
may be in part due to a lack of oxygen in the brain. Other symptoms are listed
in the table.
| Symptoms of
Pulmonary Emboli (PE) | | Symptom: | Frequency: |
| dyspnea | 73%* |
| pleuritic pain | 46% |
| cough | 43% |
| leg swelling | 33% |
| leg pain | 30% |
| hemoptysis | 15% |
| palpitations | 12%
| | wheezing |
10% | | angina
type pain | 5% |
*Note: %-ages do not add up to 100%; symptoms
can occur simultaneously | Diagnostic
tests: A patient with pulmonary emboli needs to be seen and treated
in the Emergency Department of a hospital. Several tests need to be done in rapid
succession and heparin and clot dissolving therapy needs to be started at the
same time. After an initial quick examination the Emergency Room physician
likely will want to do some simple initial tests such as oxymetry on a finger
or ear lobe and spirometry. Arterial
blood gases likely will also be obtained right away as this is giving
the physician a good inital assessment as to how extensive the clots in the lung
are. A very low partial oxygen pressure in the blood likely is associated with
a lot of clots affecting the oxygen absorption significantly. A chest X-ray and
likely will be ordered. The lung perfusion scan is done with radioactive tracer
sustances (with the radioisotope technetium 99m) and is probably the most important
of the tests. It measures the lack of perfusion in the lung tissue affected
by pulmonary emboli. The series of scans depicted under this link show a sequence
of normal scans in the upper area. In the lower half of the link abnormal perfusion
scans demonstrate a large pulmonary embolus in the right lung of this patient.
Another type of lung scan, the ventilation
lung scan, uses the inhaled gas xenon-133, which measures the air
flow into the lungs. When the lung perfusion and the lung ventilation scans
are done simultaneously, the result shows by way of subtraction where a perfusion
defect is located. The corresponding lung tissue, which is now blocked by clots
from receiving blood from the affected lung artery branch, is still ventilated
normally in this area, except in the 10% where a lung infarction has developed
(see
images). That's why about 90% of the cases with pulmonary emboli
can be diagnosed this way with confidence, which is considered to be a very reliable
test. For the remaining difficult cases where clinically the patient appears to
have pulmonary emboli, but the imaging studies do not clearly show the clots in
the lungs, the physician may want to consider a pulmonary arteriogram(or angiogram)
to show an arterial filling defect where the clot is located. Further tests such
as CT scans, spiral CT
scans, and MRI scans can be done to get more details as well, if
the extent of the clots needs to be determined. Treatment: Treatment
depends on the clinical presentation and the finding of the tests in a particular
patient. However, generally speaking a form of clot dissolving treatment (thrombolytic
therapy) is chosen. There are rapidly dissolving therapies
such as streptokinase and plasminogen activating (t-PA) substances. Then there
is clot prevention therapy utilizing heparin initially and a few days later a
switch to oral medication such as warfarin. Exact protocols have been developed
to standardize the treatment and to avoid overtreatment, which would be thinning
the blood too much and cause major bleeding in various areas (brain hemorrhage,
seriously bleeding ulcers etc.). With deep vein thrombosis following surgery often
the patient will be treated with warfarin for extended periods such as 3 to 6
months to avoid a recurrence of clots. People with atrial
fibrillation who have an ongoing risk for blood clots may have to
stay on warfarin lifelong. The newest development in treating pulmonary
emboli and other clots is by way of the use of low molecular weight heparins.
Various commercial preparations are avilable (Dalteparin, Enoxaparin, Nadroparin
and Tinzaparin are pharmacological names). They all have different brand names
as well. The dosage is different for each product as the metabolic half-life is
different for each product. However, it is now recognized by the medical
profession that these low molecular heparins are very safe and very effective.
The advantage is that they work very quickly in dissolving the clot. Once the
patient has been started on it and the doctor knows whether the patient tolerates
it and how it thins the blood, no further tests for monitoring have to be done.
With regular heparin in the hospital setting or Coumadin in the home setting blood
tests have to be done frequently to check the degree of blood thinning. The disadvantage
is that the patient has to inject a little needle with the low molecular weight
heparin into rotating spots of the skin on a regular basis (e.g. twice per day).
Small amounts of aspirin can also be combined with low molecular weight heparin
(Ref. 10). Pain relief: There is an FDA approved non-drug method
available, IceWave patches from
Lifewave, which will control pain. This is mentioned in the book "Breakthrough"
by Suzanne Somers (Ref. 11) where newer insights of antiaging medicine are also
reviewed. Although the patches are placed over acupuncture points, there are no
needles involved. Nanotechnology, a newer technology, was used in the manufacturing
of these patches and infrared (heat) waves from body heat are utilized to stimulate
an acupuncture point, which modifies pain perception and reduces pain to half
or less. Medically this would be considered an excellent pain reliever. For more
info on the patches see the IceWave patches from Lifewave link above (click "products").
In the US a 5 pack of the IceWave spray is available that can be directly sprayed
onto the skin in the area where the pain is located. |
