Embolus - What it is, Why it is Formed, Symptoms, Care

Generality

An embolus is any insoluble foreign body circulating in the blood, capable, if it reaches an artery or vein of its own size, of blocking the blood flow in the same way as a stopper.

The nature of an embolus can vary enormously; in fact, emboli can be: abnormal blood clots, fat lumps, lumps of amniotic fluid, air bubbles, cholesterol crystals, talc granules, tissue portions, splinters, etc.

The therapy of an embolus depends on 3 factors, obtainable only through accurate diagnostic investigations, which are: nature, size and location.

What is an embolus?

Embolus is the medical term that defines any anomalous, mobile and insoluble mass, circulating in the blood and capable, if it reaches an artery or a vein of its same size, of interrupting the blood flow in a way very similar to a cork.

The presence with occlusive effect of one or more emboli is a condition that, in medicine, is called embolism .

The phenomena of embolism - therefore the presence of an occlusive embolus - can be lethal for the victim, since they reduce or prevent the flow of blood in one or more organs (the organ concerned depends on the site of the embolus).

Curiosity

Coining the term "embolus" was the pathologist and scholar Rudolf Virchow in 1848. Rudolf Virchow is known to most for his contribution to the recognition of the main risk factors for thrombosis ; 3 in number and labeled (not by chance) as " Virchow triad ", these factors are hypercoagulability, stasis or turbulence of blood flow and endothelial damage.

How can an embolus clog a blood vessel?

Emboli travel through the vast network of arteries and veins in the human body, exploiting blood circulation.

The possibility that an embolus has to obstruct a blood vessel is closely related to its size. In fact, as long as it is smaller than the vessel it passes through, any embolus is so to speak without consequences; on the contrary, when it penetrates into arteries or veins of size equal to its diameter, it is increasingly difficult to proceed, so much so that at a certain point it stops and blocks the blood vessel in which it resides.

Emboli and thrombus are the same thing?

The embolus is often confused with the thrombus ; however, there are important differences between the two:

• First, the thrombus always has only a sanguine nature; it is in fact an insoluble abnormal blood clot. The embolus, on the other hand, can have very different natures: it can be an abnormal blood clot, it can be a crystal of cholesterol, it can be an air bubble etc. (re-reading the definition of embolus, the reader will notice that the embolus is simply defined as an "anomalous mass");
• Secondly, while the embolus is a mobile entity circulating freely in the blood until it reaches a vessel of its own size, the thrombus is a fixed presence, anchored to the inner wall of a blood vessel.

The presence of a thrombus inside a blood vessel is the medical condition known as thrombosis .

FROM WHERE IS THE CONFUSION BETWEEN EMBOLO AND TROMBO

There are basically two reasons for confusing emboli with thrombus:

• The possibility that a thrombus may result from an embolus. In the blood vessel in which a thrombus is formed, blood flow often tends to be turbulent; excessive turbulence can cause a thrombus to flake, disseminating, within the wide vascular network of the human body, small mobile and insoluble blood clots. These clots are in all respects emboli.
• When it reaches a large size, the thrombus can block the flow of blood in that part of the blood vessel in which it originated, emulating the behavior of an embolus when it reaches an artery or vein of same size.

  Therefore, although they are notably different, emboli and thrombus can have the same consequences: occlude a blood vessel and subsequently block the supply of blood to a certain organ or tissue.

Causes

There are numerous types of embolus; in fact, an embolus can be:

• A blood clot . The presence of an occlusive blood-like embolus is known as thromboembolism or blood clot embolism ; the term thromboembolism finds justification in the fact that, in the circumstances in question, the embolus originates from a thrombus.
• A lump of fat . When the occlusive embolus is a lump of fat, the resulting embolism is called a fat embolism .
• An air bubble (or a gas bubble ). In cases where the occlusive embolus is an air bubble, the resulting embolism is known as a gas embolism .
• A crystal of cholesterol . The embolism following the presence of a cholesterol crystal is known as cholesterol embolism, an embolism from cholesterol crystals or atheroembolism .
• A lump of amniotic fluid . When the occlusive embolus is a lump of amniotic fluid, the resulting embolism is called an amniotic fluid embolism, the embolism from amniotic fluid is a rare complication of pregnancy.
• A granule of talc . The resulting embolism is known, quite simply, as a talc embolism .
• A parasite (eg: tapeworm) or a group of parasites (eg: agglomeration of pyogenic bacteria). When the occlusive embolus is a parasite or agglomerate of parasites, the resulting embolism is called septic embolism .
• A foreign body like a splinter or a needle .
• A portion of fabric .

Thromboembolism or blood clot embolism

The mechanism of formation of blood clots is a physiological response of the organism, in the presence of wounds or cuts on a tissue, to avoid excessive blood loss.

A group of particular blood cells - called platelets - and a class of equally particular enzymes - called coagulation factors - participate in the coagulation .

Due to certain medical conditions, including obesity, heart disease or cancer - human beings can be the victim of unnecessary blood clotting phenomena, that is, that occur without a real blood loss to stem; the blood clots resulting from these phenomena, therefore, can anchor themselves to the inner wall of a vessel (thrombus) or travel within the wide vascular network of the human body, exploiting the blood circulation (embolus).

Thromboembolism is a possible consequence not only of the second circumstance, but also of the first (readers are reminded that a thrombus can originate a blood embolus).

Curiosity

One of the main causes of pulmonary blood clot embolism is a form of thrombosis that specifically affects the veins of the legs and is known in the medical field as deep vein thrombosis .

Fat embolism

In fat embolism, the lump of fat that plays the role of embolus derives from the adipose tissues of the human body.

In most circumstances, emboli of adipose origin are the consequence of very serious traumatic injuries, such as fractures of long bones or high-grade burns; more rarely, they are the result of: orthopedic procedures (eg: hip prostheses), bone biopsies, episodes of pancreatitis, the presence of so-called fatty liver, liposuction interventions, prolonged use of corticosteroids, hemoglobinopathies and osteomyelitis.

Gas embolism

In gaseous embolism, the air bubble that covers the role of embolus is the result of particular pressure conditions, which favor the entry of air gases into a blood vessel exposed to the latter.

Pressure conditions, capable of giving rise to a gas embolism, can occur at:

• A venous injection, by syringe, poorly practiced;
• Surgical interventions that require the insertion of central venous catheters either in the subclavian vein or in the jugular vein;
• Artificial ventilation, practiced during severe chest trauma;
• Scuba diving ;
• Other (pulmonary barotrauma, bomb blast, sexual intercourse, etc.).

Cholesterol embolism

Cholesterol crystals with the dangerous role of occlusive embolus may derive from: the fragmentation of an atherosclerotic plaque, vascular surgery or angiography operations (NB: in the second and third circumstances, cholesterol embolism is a surgical complication).

Embolism from amniotic fluid

In embolism from amniotic fluid, the embolus is the result of the abnormal passage of a lump of amniotic fluid into the circulatory stream.

Recalling that the embolism from amniotic fluid is a possible complication of pregnancy, in a pregnant woman the abnormal passage of a lump of amniotic fluid in the blood is more frequent at certain times, including:

• Labor;
• The post-partum phase;
• After an abortion;
• After an amniocentesis.

Curiosity

As a rule, the phenomena of embolism due to amniotic fluid affect the pulmonary arteries (pulmonary embolism due to amniotic fluid), causing symptoms such as dyspnea and heart problems.

Fortunately, according to some statistical studies reported in North America, pulmonary embolism due to amniotic fluid involves one pregnancy per 15, 000.

Talc embolism

In cases of talc embolism, the talcum granule which acts as an embolus has, as a rule, the use of injectable drugs (eg, heroin) as a triggering circumstance. The preparation of these narcotics, in fact, very often involves the mixing of a certain amount of narcotic with talc (which, of course, is confused with blood, after the injection of the drug).

Risk factors

Among the risk factors for embolism, doctors include:

• Overweight and obesity;
• Advanced age;
• Cigarette smoke;
• The presence of some heart disease;
• Prolonged immobility, for example due to serious illnesses, bone fractures or long journeys by plane or car;
• The state of pregnancy.

Symptoms and Complications

The blood vessels of the human body more frequently subject to occlusion by an embolus (therefore, in essence, the blood vessels most subject to embolism) are:

• Arteries that supply the brain . Any interruption or reduction of the blood supply to a brain district takes the generic name of stroke ; the interruption or reduction due to the presence of an embolus is called an embolic ischemic stroke ;
• Blood vessels that carry oxygen-poor blood from the heart to the lungs ( pulmonary arteries and their branches ). When an embolus obstructs the patency of the pulmonary arteries or their branches, the doctors talk about pulmonary embolism .

  Reminding readers that the pulmonary arteries and their branches have the task of directing oxygen-poor blood from the heart to the lungs, pulmonary embolism compromises the process of blood oxygenation, with obvious repercussions on the good health of organs and tissues (these, in fact, they no longer receive adequately oxygenated blood, therefore they suffer and function badly;

• The arteries that feed the myocardium, or so-called coronary arteries . Coronary artery obstruction due to one or more emboli is called coronary embolism .

  Coronary embolism phenomena can give rise to a heart attack, the outcome of which can sometimes be lethal.

Diagnosis

Detection of an embolus may require a wide variety of tests and diagnostic tests.

Among these examinations and diagnostic tests, the physical examination, anamnesis and diagnostic procedures for ultrasound imaging, CT scans, nuclear magnetic resonance (NMR) and angiography deserve a mention.

The precise identification of emboli and their characteristics (nature, size, location, etc.) is very important, because it allows doctors to plan the most appropriate therapy.

Care and Treatment

Embolus therapy depends on:

• Its nature. A blood clot requires treatment other than an air bubble;
• Its dimensions;
• Its location.

Among the most important feasible treatments against embolic phenomena are embolectomy surgery, anticoagulant and thrombolytic drug therapies (NB: valid only for cases of thromboembolism) and hyperbaric chamber treatment (NB: valid only in the case of gas embolism).

embolectomy

Embolectomy is the surgical procedure to remove one or more emboli that impede blood circulation.

Being a very delicate procedure and from which complications can sometimes result fatal for the patient, embolectomy is reserved for the most critical episodes of embolism and for which doctors consider any other type of treatment less invasive useless.

Embolectomy is a surgical intervention reserved for emergencies.

Anticoagulants and thrombolytics

When the occlusive embolus is a blood clot, the treatment applied in the first instance is a drug therapy based on anticoagulants and / or thrombolytics.

Although with different mechanisms of action, in fact, anticoagulants and thrombolytics have the useful effect of favoring the dissolution of abnormal blood clots, present inside the blood vessels.

• Anticoagulant drugs (eg low molecular weight heparin and warfarin): they have the power to slow down / interrupt the blood clotting process;
• Thrombolytic drugs (eg: streptokinase, alteplase and reteplase): possess the property of dissolving blood clots.

Generally, in the presence of blood-borne emboli, doctors tend to give precedence to anticoagulants, since the latter present fewer adverse effects than thrombolytics.

iperbaric room

The hyperbaric chamber (or chamber for hyperbaric therapy ) is a physical place, present in hospitals and in the most modern medical clinics, in which an individual can breathe pure oxygen or oxygen-rich compressed air, at levels of pressure decidedly superior to those present in the ambient air.

The hyperbaric chamber is the most indicated treatment in the case of gas embolism, since, having a particular effect on blood pressure, it favors the elimination of the air bubble acting as an embolus.

The use of the hyperbaric chamber for therapeutic reasons represents one of the main techniques of application of the so-called oxygen therapy .

Prognosis

Of course, early diagnosis and timely treatment reduce the risk of death associated with an embolus.

As stated at the beginning, the presence of an embolus can have fatal consequences.