Pulmonary Embolism

Pulmonary embolism Classification and external resources
A CT chest showing many gaps in the main branches of pulmonary arteries during pulmonary embolism.
ICD - 10	I26.
ICD - 9	415.1
DiseasesDB	10956
MedlinePlus	000132
eMedicine	med/1958
MeSH	D011655

There is talk of pulmonary embolism when clot in the blood will clog the arteries supplying the lungs. This is one of two events with deep vein thrombosis , the thromboembolic disease. Pulmonary embolism is therefore a complication of deep vein thrombosis.

The first description was made by Virchow in 1859 ^Epidemiology

United States, its annual incidence is about 70 per 100 000 persons .

Diagnosis

Clinical

The classic picture of pulmonary embolism include shortness of breath ( dyspnea ), a chest pain , a tachycardia , sometimes the patient may vomit blood ( hemoptysis ).

Clinical examination showed an increase in respiratory rate ( tachypnea ), a rapid pulse ( tachycardia ). There is no sign of left heart failure (normal lung auscultation). If pulmonary embolism is important, we can see signs of right heart failure (dilated = jugular vein engorgement jugular vein, pain in the liver = hpatalgie, hepato-jugular reflux ...).

Scores of clinical predictions

In the presence of dyspnea or chest pain, the Wells score used to evaluate the clinical probability of pulmonary embolism :

• score below 2 = Low probability <5%
• intermediate score (2-6) = probability of 20-30%
• score above 6 = high probability> 60%

That Philip S. Wells has established these criteria.

Other scores, based on the same principle, were developed. Most notable is Geneva which includes 8 variables: age> 65 years (1 point), ATCD of DVT or PE (3 points), recent surgery or fractures <1 month (2 points), active cancer (2 points), pain in the leg (3 points), hemoptysis (2 points), heart rate 75 to 94 beats / min (3 points) or 95 beats / min (5 points), and pain on palpation of deep veins and unilateral leg edema (4 points).

• score 0-3 = low probability <8%
• intermediate score (4-10) = probability of 28%
• score greater than or equal to 11 = high probability of 74%.

Adage

In fact, a pulmonary embolism may be present in extremely diverse arrays: long-term fever, pain, atypical discomfort or syncope , shock , or be totally silent. A classic adage in medicine says "it does not understand the patient's chart: it is a pulmonary embolism until proven otherwise." Similarly, there is often a poor correlation between the size of the embolism and the clinical picture, but poor tolerability (drop in blood pressure, signs of right heart failure, significant dyspnea) is strongly in favor of a massive pulmonary embolism.

ECG

The ECG is not specific and changes are very fickle. The ECG of an "acute pulmonary heart," which EP is the main etiology, reflecting a sudden overload of right ventricular stroke work due to an increase in often brutal right ventricular afterload related to arterial occlusion lung.

We can find some anomalies, early onset and reversible. Five major abnormalities suggest the diagnosis of acute pulmonary heart :

• Onset of atrial fibrillation fast. tachycardia Sinus, found in about 25% of PE;
• S1Q3 appearance, found in about 50% and nonspecific. Defined by an S wave in DI and Q waves in DIII.
• Branch block incomplete right, but often fleeting. Defined by a QRS duration> 0.08 s and <0.12 s and a delay to registration of the deflection in V1 intrinscode> 0.04 sec The QRS has an aspect RSR 'in V1.
• Leftward shift of the transition zone of QRS, found in about 50% of cases;
• Repolarization disorder, found in about 70% and lasting several days, with inverted T waves in the anterior territory (V1 to V3) with sharp and symmetrical T waves, suggestive of ischemia.

Biology

It is identical to that of deep vein thrombosis ( D-dimer , coagulation (clotting balance), seeking a constitutional anomaly if necessary). In particular, a normal D-dimer to exclude the diagnosis in most cases , unless the diagnosis of pulmonary embolism is considered from the outset as highly probable .

The arterial blood gases showed a decrease in blood oxygen content ( hypoxia ) and decreased carbon dioxide content in the blood ( hypocapnia ). If these parameters are very disturbed, it is for a major pulmonary embolism.

Medical Imaging

She has two goals:

• positive diagnosis: view the thrombus
• the diagnosis of severity: number and type of pulmonary arteries affected.

It offers a choice of:

• The scintigraphic pulmonary
  • Infusion: injecting intravenously a radioactive marker and placed a camera to detect radioactivity in the thorax of the patient. If there is a pulmonary arterial occlusion, then the marker is not detected in the affected lung lobe. There is then a low uptake makes the diagnosis of embolism. The test is simple, very dangerous for the patient even if he uses of radioisotopes. It can make a positive diagnosis and a diagnosis of severity (size of the low uptake). By cons, it may miss small migration. Similarly, any lung disease (and even the simple act of smoking) affects the images by making them more difficult to interpret.
  • perfusion and ventilation is coupled the previous review with a second scan , known as ventilation. The patient breathes a radioactive gas which is then detected at the alveolar level by a camera. Typically a pulmonary embolism is characterized by a low uptake on the perfusion scan with a scan of normal ventilation in the same place. This helps refine the diagnosis in cases of preexisting pulmonary pathology. The review comes, however significantly more expensive.
• The pulmonary angiography : a catheter (long thin tube) is introduced through the upper (humeral) and vaginal (femur) into the trunk of the pulmonary artery and an iodinated contrast agent is injected. Several X-rays are then taken according to various impacts. It allows a positive diagnosis and severity. Conventionally considered the gold standard, for use when other investigations did not resolve. But it is an invasive examination with the problem of injection of iodinated ( renal failure , allergy ) and is less used.

scan, showing an embolus in the central pulmonary arteries (so-called saddle embolism)

• The scanner spiral of pulmonary arteries or CT angiography of pulmonary arteries: an iodinated contrast agent is injected intravenously. The rotary motion and longitudinal (spiral nature) of the head of the scanner allows to visualize the pulmonary arteries and proximal middle and a little less their distally. This is an excellent review of positive diagnosis and severity, even if the risks associated with the use of iodine products and radiation persist. It is less invasive than conventional angiography. It also allows the evaluation of several other intrathoracic structures (aorta, mediastinum, lung, pleura), in addition to the evaluation of pulmonary arteries. It is often regarded as the new gold standard.

• The completion within 48 hours of a Doppler ultrasound to search for phlebitis or lower limb deep veins of the abdominal deep venous system must be systematic.

Except: the echocardiography : does exceptionally visualize a thrombus, but introduces a number of arguments if the embolism is massive dilatation of right cavities with increasing pressure lines.

The chest radiograph shows no specific image. It can essentially eliminate another cause shortness of breath. The MRI is difficult realization for the diagnosis of pulmonary embolism with a sensitivity-optimal .

The choice of diagnostic test depends on the availability of these and the probability of positive diagnosis.

Evolution of pulmonary embolism

Under a well-conducted treatment, pulmonary embolism can heal without sequelae, but there may be shortness of breath more or less disabling.

Massive pulmonary embolism can lead to shock or even a cardiovascular arrest. Its mortality reached just over 15% in the first three months .

Most pulmonary emboli (60% to 80%) have no clinical manifestation as the thrombus is small.

The treatment of pulmonary embolism

Several recommendations on the management of pulmonary embolism were published by international bodies. The most recent were in 2007 by the American College of Physicians and in 2008 by the European Society of Cardiology .

Hospitalization is required. Case of severe pulmonary embolism, admission to intensive care is preferable.

An oxygen therapy is started at first in a noninvasive way (to re-evaluate the tolerance of embolism).

An anticoagulation intravenously or by subcutaneous heparin or LMWH is started with a relay in 7 days (to prevent thrombocytopenia induced by heparin) by AVK which will be continued for at least three months following the context. The choice between unfractionated heparin (in syringe pump) and LMWH is mainly based on prescribing habits, both options have equivalent efficacy .

The lift is made after 48 hours minimum anticoagulation well conducted in the presence of a nurse and with elastic-type band for varicose veins.

If pulmonary embolism is severe (poor clinical tolerance and / or importance of embolism on imaging) with life-threatening, it can provide a treatment fibrinolytic (or thrombolysis).

• The latter aims to dissolve the clot quickly (within hours instead of days). It is injected into a course of infusion of short duration (usually initial bolus followed by infusion over 2 hours).
• The risk of bleeding may be important: it is essential to respect the cons-indications (recent surgery, illness hemostasis, arterial puncture, uncontrolled hypertension, recent stroke ...)

If cons-effects or failure of thrombolysis, as a last resort, surgical thrombectomy rescue may be considered by sternotomy under cardiopulmonary bypass.

References

• Portal medicine

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