Pulmonary Embolism

The pulmonary embolism is one of the two demonstrations, with the major venous Thrombose, of the thrombo-embolic Maladie . The pulmonary embolism is a complication of major venous thrombosis. One speaks about pulmonary embolism when a clot circulating in blood will stop the arterial system irrigating the lung.

The diagnosis

Private clinic

The traditional table of the pulmonary embolism comprises breathlessness (Dyspnée), thoracic Douleur, sometimes the patient can spit of blood (Hémoptysie).

The clinical examination shows an increase in the respiratory frequency (Polypnée), a fast pulse (Tachycardie). There is no left sign of cardiac failure (normal pulmonary sounding). If the pulmonary embolism is important, one can see signs of right cardiac failure (dilated jugular vein = jugular turgescence, pain on the level of the liver = hépatalgie…).

In the presence of a dyspnea or of a thoracic pain, the score of Wells makes it possible to evaluate the clinical probability of a pulmonary embolism:

score lower than 2 = probability weak < 5%
intermediate score (2 to 6) = probability from 20 to 30%
score higher than 6 = strong probability > 60%

ECG is not specific and the modifications are very inconstant: simple increase in the heart rate (tachycardia) generally, modification of the repolarization in derivations close to the ventricle right, incomplete block right, deviation of the electric axis of the heart towards the line (signs of right overload).

Pulmonary radiography is appreciably normal.

In fact, a pulmonary embolism can arise under extremely various tables: fever with the long course, pains atypical, faintness or syncope, state of shock, to even be completely quiet. A traditional proverb in medicine known as “one does not include/understand anything in the table patient: it is a pulmonary embolism until the proof of the opposite”. In the same way, there is often a bad correlation between the importance of the embolism and the clinical picture, but a bad tolerance (falls tensionnelle, sign of right cardiac failure, important dyspnea) is strongly in favor of a pulmonary embolism massive.

Biology

It is identical to that of the major venous Thrombose (D-dimer S, Hémostase (assessment of coagulation), search for a constitutional anomaly if need be).

The arterial gazometry watch a reduction in the oxygen contents of blood ( Hypoxia ) and a reduction in the carbonic gas contents of blood ( Hypocapnie ). If these parameters are very disturbed, that is in favor of a pulmonary embolism important.

Medical imagery

It has two goals:

to make the positive diagnosis: to visualize the thrombus
to make the diagnosis of gravity: number and type of pulmonary arteries reached.

One has with the choice:

the pulmonary Scintiscanning :

of perfusion : one injects by venous way a radioactive marker and one places a camera of detection of the radioactivity on the level of the thorax of the patient. If there exists a pulmonary arterial occlusion, the marker is then not detected on the level of the pulmonary lobe concerned. One then notes a hypofixation which makes carry the diagnosis of embolism. It is a simple examination, not very dangerous for the patient even if it employs radio operator isotopes. It makes it possible to make a positive diagnosis and a diagnosis of gravity (size of the hypofixation). On the other hand, it can pass beside small migrations. In the same way, any pulmonary pathology (and even the simple fact of smoking) deteriorate the images while returning them with difficulty interprêtable.
of perfusion and ventilation : one couples the preceding examination with one second Scintigraphie, known as of ventilation. The patient breathes a radioactive gas which is detected then at the alveolar level by a camera. Typically a pulmonary embolism is characterized by a hypofixation on the scintiscanning of perfusion with a Scintigraphie of normal ventilation at the same place. That makes it possible to refine the diagnosis in the event of preexistent pulmonary pathology. The examination returns however appreciably expensive.

the pulmonary Angiographie : a Cathéter (long and fine pipe) is introduced by high way (humérale) or by low way (femoral) until in the trunk of the pulmonary artery and a product of iodized contrast is then injected. Several radiological stereotypes are then taken according to various incidences. It allows a positive diagnosis and of gravity. Classically regarded as the examination of reference, to use when other explorations do not make it possible to slice. It is however an invasive examination, with the problem of the injection of iodized products (Impaired renal function, Allergie) and which is less and less used.

the spiral scanner of the pulmonary arteries or angioscanner of the pulmonary arteries: a product of iodized contrast is injected into intravenous. The rotary and longitudinal movement (spiral character) of the head of the scanner makes it possible to visualize the pulmonary arteries well proximales and averages and a little less better their distality. It is an excellent examination of positive diagnosis and gravity, even if the risks related to the use of iodized products and radiation persist. It is less invasive than the conventional angiography. It allows also the evaluation of several other intrathoracic structures (aorta and médiastin, lung, plèvre), in addition to the evaluation of the pulmonary arteries. He is regarded sometimes as the new examination of reference.

the realization in the 48 hours of a echography Doppler in the search of a major phlebitis of the lower extremities or veins of the abdominal major venous network must be systematic.

With share: the cardiac echography : allows only exceptionally to visualize a thrombus, but brings a certain number of arguments if the embolism is massive: dilation of the right cavities with increase in the right pressures.

The pulmonary radiography does not show any specific image. It primarily makes it possible to eliminate another cause with dyspnea.

The choice of the examination diagnosis depends on the availability of those and the probability of the positive diagnosis.

Evolution of the pulmonary embolism

Under a well led treatment, the pulmonary embolism can cure without after-effect, but it can remain breathlessness more or less invalidating.

A massive pulmonary embolism can lead to a state of shock, even with a cardio-circulatory Arrêt.

The majority of the pulmonary embolisms (60% to 80%) do not have any clinical demonstrations since the thrombus is of small size.

Treatment of the pulmonary embolism

The hospitalization is essential. If it is about a pulmonary embolism engraves, the admission in intensive care is preferable.

A Oxygénothérapie is started initially in a noninvasive way (to be revalued with the tolerance of the embolism).

A anticoagulation into intravenous or subcutaneous by heparin or HBPM is begun with a relay in the 7 days (to avoid a Thrombopénie induced by heparin) by AVK which will be continued at least for 3 months following the context.

The rising is made after 48 H minimum of anticoagulation led well in the presence of a nurse and with elastic applications of type bandages with varixes.

If the pulmonary embolism is serious (bad clinical tolerance and/or importance of the embolism on the imageries) with a vital risk, the purpose of one can propose a fibrinolytic treatment

The latter is to dissolve quickly the clot (a few hours instead of a few days). It is injected in a cure of perfusion of short duration (in general bolus initial followed by a perfusion over 2 a.m.).
the hemorrhagic risk can be important: it is capital to respect counter-indications (recent surgery, disease of the hémostase, arterial puncture, not controlled HTA, recent AVC…)

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