EMBOLISM
An
embolism is any intravascular mass that has been carried down the bloodstream
from its site of origin, resulting in the occlusion of a vessel. There are many
types of emboli:
·
Thromboemboli:
most common (98%)
·
Atheromatous emboli (severe
atherosclerosis)
·
Fat emboli (bone fractures and soft
tissue trauma)
·
Bone marrow emboli (bone fractures
and cardiopulmonary resuscitation [CPR])
·
Gas emboli cause decompression
sickness (“the bends” and caisson disease) when rapid ascent results in
nitrogen gas bubbles in the blood vessels
·
Amniotic fluid emboli are a
complication of labor that may result in DIC; fetal squamous cells are seen in
the maternal pulmonary vessels
·
Tumor emboli (metastasis)
·
Talc emboli (IV drug abuse)
·
Bacterial/septic emboli (infectious
endocarditis)
Pulmonary emboli (PE) are
often clinically silent and are the most commonlymissed diagnosis in
hospitalized patients. They are found in almost 50% of all hos-pital autopsies.
Most PE (95%) arise from deep leg vein thrombosis (DVT) in the leg; other
sources include the right side of the heart and the pelvic venous plexuses of
the prostate and uterus.
Diagnosis
of a PE can be established when V/Q lung shows a scan V/Q mismatch. Doppler
ultrasound of the leg veins can be used to detect a DVT. Additionally, plasma
D-dimer ELISA test is elevated.
Most
cases are clinically silent and resolve.
Infarction
is more common in patients with cardiopulmonary compromise. Symp-toms include
shortness of breath, hemoptysis, pleuritic chest pain, and pleural effu-sion.
On gross examination there is typically a hemorrhagic wedge-shaped infarct. The
infarction heals by regeneration or scar formation.
·
Sudden death can occur when large
emboli lodge in the bifurcation (saddle embolus) or large pulmonary artery
branches.
·
Chronic secondary pulmonary
hypertension is caused by recurrent PEs, which increase pulmonary resistance
and lead to secondary pulmonary hypertension.
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