2. Definition
EMBOLUS = “stopper”
A detached intravascular solid, liquid or
gaseous mass that is carried by the blood to a
site distant from its point of origin.
Coined by Rudolf Virchow
5. Almost all emboli represent some part of a dislodged thrombus
Thromboembolism.
Unless otherwise specified, emboli should be considered thrombotic in
origin.
6. Emboli lodge in vessels too small to permit
further passage causing partial or complete
vascular occlusion Infarction of the tissue
7. Types of emboli
Depending upon matter in the emboli
Depending on infectivity
Depending on source of emboli
Depending upon flow of blood
8. Depending upon matter in the emboli
I) solid
Detached thrombi (thromboembolism), atherosclerotic
material , tumour cell clumps , parasites , bacterial
clumps
II) liquid
fat globules , amniotic fluid
III) gaseous
Air Embolism
10. Depending on source of emboli
Cardiac- vegetation of endocarditis , infarct in
left ventricle
Arterial- brain , spleen , kidney
Venous- pulmonary vein
lymphatic
11. Depending upon flow of blood
Paradoxical or crossed venous side to arterial side
of circulation or vice versa
- Patent foramen ovale , septal defect of heart.
Retrograde travels against the flow of blood
- Metastatic deposits in spine from ca.prostate
Saddle – at bifurcation of a vessel
12. Emboli
Systemic thromboemboli
Pulmonary thromboemboli
Fat emboli
Marrow emboli
Air emboli
Amniotic fluid emboli
Tumour emboli
Others – foreign bodies e.g. glass, metal
fragments (even occasionally bullets), etc.
19. PULMONARY EMBOLISM
Fragmented thrombi from DVTs are carried
through progressively larger channels and the
right side of the heart before reaching the
pulmonary arterial vasculature.
20. PULMONARY EMBOLISM
Depending on the size of the embolus, it can
occlude the main pulmonary artery, straddle the
pulmonary artery bifurcation (saddle embolus),
or pass out into the smaller, branching arteries.
21. PULMONARY EMBOLISM
Rarely, an embolus can pass through an
interatrial or interventricular defect and gain
access to the systemic circulation (paradoxical
embolism).
26. Prevention and treatment
Prophylactic therapy includes early ambulation
in postoperative and postpartum patients, elastic
stockings and graduated compression stockings
for bedridden patients, and anticoagulation in
high-risk individuals.
Insertion of a filter (“umbrella”) into the inferior
vena cava in an already seriously ill patient.
Treatment of existing pulmonary embolism often
includes anticoagulation, preceded by
thrombolysis in some cases.
27. Fat Embolism
Commonly found at autopsies –
asymptomatic
injuries to
adipose tissues (trauma, burns)
long bones (trauma)
28. Fat Embolism
Severe fat embolism FAT EMBOLISM SYNDROME –
10% FATAL
Seen 1 – 3 days after injury
- pulmonary insufficiency
- neurological symptoms
- anemia
- thrombocytopenia – petechial rash
- DIC
33. Air-embolism
Gas bubbles within the
circulation can coalesce to
form frothy masses that
obstruct vascular flow.
> 100 cc of air are required to
have a clinical effect in the
pulmonary circulation.
36. DECOMPRESSION SICKNESS
Form of gas embolism.
Occurs when individuals experience sudden
decreases in atmospheric pressure.
Scuba and deep sea divers, underwater
construction workers, and individuals in
unpressurized aircraft in rapid ascent.
37. DECOMPRESSION SICKNESS
When air is breathed at high pressure (e.g., during a
deep sea dive), increased amounts of gas particularly
nitrogen are dissolved in the blood and tissues.
If the diver then ascends (depressurizes) too rapidly, the
nitrogen comes out of solution in the tissues and the
blood.
39. DECOMPRESSION SICKNESS
BENDS
• The rapid formation of gas bubbles within
skeletal muscles and supporting tissues in
and about joints painful condition called
the bends.
CHOKES
• In the lungs, gas bubbles in the vasculature
cause edema, hemorrhage, and focal
atelectasis or emphysema respiratory
distress called the chokes.
40. DECOMPRESSION SICKNESS
A more chronic form of decompression sickness
is called caisson disease.
Persistence of gas emboli in the skeletal system
leads to multiple foci of ischemic necrosis.
Common sites are the femoral heads, tibia, and
humeri.
41. Amniotic fluid embolism
Ominous complication of labor and the
immediate postpartum period.
Incidence approximately 1 in 40,000 deliveries.
Mortality rate is up to 80%.
Fifth most common cause of maternal mortality
worldwide.
42. Amniotic fluid embolism
Cause - infusion of amniotic fluid or fetal tissue
into the maternal circulation via a tear in the
placental membranes or rupture of uterine
veins.
43. Amniotic fluid embolism
The onset is characterized by
sudden severe dyspnea,
cyanosis,
shock,
neurologic impairment ranging from headache
to seizures and coma.
If the patient survives the initial crisis
pulmonary edema develops, along with DIC.
44. Amniotic fluid embolism
Classic findings include the presence of
squamous cells shed from fetal skin, lanugo hair,
fat from vernix caseosa, and mucin derived from
the fetal respiratory or gastrointestinal tract in
the maternal pulmonary microvasculature.
46. Amniotic fluid embolism
Two small pulmonary arterioles are packed with laminated swirls of fetal
squamous cells.
