Overview.
Non-thrombotic pulmonary embolism is a relatively rare disease or clinical syndrome in which the underlying cause is obstruction of the pulmonary arterial system by a non-thrombotic embolus. They include mainly fat embolism, air embolism, and amniotic fluid embolism. Symptoms and treatment vary depending on the type of embolism.
Causes
1. Fat embolism
Fat embolism is common in trauma patients, especially long bone or pelvic fracture. Fat embolism also commonly occurs after extensive injury to the subcutaneous fat if a heavy blow occurs. Less common causes of fat embolism include plastic surgery, liposuction, and intravenous hypernourishment.
2. Air embolism
Intravenous air embolism is the most common, mostly of medical origin, and is a serious complication of medical puncture, positive pressure ventilation, and surgery.
3. Amniotic fluid embolism
Amniotic fluid entering the maternal circulation causes the release of vasoactive substances such as endotoxin mediators, producing an allergy-like reaction or sepsis.
Symptoms
1. Fat embolism
Typical presentation is usually progressive respiratory inactivity, neurologic symptoms, fever, and a blotchy rash 12 to 36 hours after trauma. CNS symptoms include confusion, coma, delirium, restlessness, confusion, numbness, and seizures.
2. Air embolism
The clinical manifestations lack specificity and are mainly characterized by dyspnea, chest pain, and hypotension.
3. Amniotic fluid embolism
The first manifestation is choking, shortness of breath, irritability and other symptoms, followed by dyspnea, convulsions, coma, blood pressure drop or shock, disseminated intravascular coagulation.
Examination
1. Fat embolism
(1) X-ray chest radiograph: the manifestation is mild, including bilateral fuzzy reduced transparency areas or patchy solid shadows, and more serious patients have widely distributed solid shadows.
(2) CT: Bilaterally confined or diffusely distributed ground-glass density shadows, confined or fused solid shadows, and blurred central nodules <10 mm in diameter in the lobules of the lungs.
2. Air embolism
(1) X-ray film: common heart, pulmonary artery permeability increased, local pulmonary blood reduction, pulmonary edema and pulmonary hypertension.
(2) CT examination: show gas shadows in the vena cava, right atrium and pulmonary artery.
3. Amniotic fluid embolism
X-ray flat film: diffuse lamellar shadows in both lungs, distributed along the pulmonary hilar, and the heart shadow may be enlarged.
Diagnosis
1. Fat embolism
(1) Main symptoms: progressive respiratory distress, neurological symptoms, fever, and blotchy rash 12-36 hours after trauma.
(2) Chest radiograph: multiple patchy shadows in both lungs; CT shows extensive ground-glass-like shadow changes and solid changes in both lungs.
2. Air embolism
(1) Main manifestations: dyspnea, chest pain, hypotension.
(2) X-ray film: common heart, pulmonary artery permeability increase, local lung blood decrease, pulmonary edema and pulmonary hypertension; CT examination shows gas shadow in vena cava, right atrium and pulmonary artery.
3. Amniotic fluid embolism
(1) Early clinical manifestations: sudden hypotension, choking, shortness of breath, irritability, followed by coma and disseminated intravascular coagulation.
(2) The diagnosis of amniotic fluid embolism mainly relies on autopsy.
Treatment
1. Fat embolism
It mainly includes correcting hypoxia, protecting lung and brain functions, applying glucocorticoids, maintaining acid-base balance and preventing various complications.
2. Air embolism
Treatment includes oxygenation, puncture or catheterization.
3. Amniotic fluid embolism
Amniotic fluid embolism is an obstetric emergency with a mortality rate as high as 80%. Treatment mainly includes anti-allergy, anti-shock, reducing pulmonary hypertension, correcting coagulation disorders and symptomatic supportive therapy.