Home > Pulmonary embolism
A pulmonary embolism occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs, causing vascular obstruction and impaired gas exchange.1 Signs and symptoms
Signs of PE are (sudden) shortness of breath ( dyspnea), rapid breathing rate ( tachypnea ), pleuritic chest pain, cough, hemoptysis (coughing up blood), and in severe cases, hypotension, loss of consciousness, and death.
2 Causes
The most common sources of embolism are pelvic vein thromboses or proximal leg deep venous thrombosis (DVTs).
Generally PE's are caused by a synergism of several predisposing factors, roughly to be divided into genetic, acquired and circumstantial causes:
- Genetic
- Factor V, Leiden type (3% of the population are heterozygous for FVL).
- Prothrombin mutation (G20210A).
- Protein C deficiency.
- Protein S deficiency.
- Antithrombin III deficiency.
- High homocysteineThe metabolic intermediate homocysteine is an amino acid created by the single carbon chemistry of S-adenosyl-methionine. It can be converted back to methionine, or converted to cysteine or taurine via the transsulfuration pathway. Note: need homocysteine levels due to MTHFR mutation.
- Plasminogen and fibrinolysisFibrinolysis is the process where a fibrin clot, the product of coagulation, is broken down. Its main enzyme, plasmin, cuts the fibrin mesh at various places, leading to the production of circulating fragments that are cleared by other proteinases or by t disorders.
- Acquired
- antiphospholipid antibodies
- anticardiolipin antibodies and/or
- lupus anticoagulant s
- Renal diseaseThe kidneys are bean-shaped excretory organs in vertebrates. Part of the urinary system, the kidneys filter wastes (especially urea) from the blood and excrete them, along with water, as urine. The medical field that studies the kidneys and diseases affec (renal loss of antithrombin)
- Paroxysmal nocturnal hemoglobinuriaParoxysmal nocturnal hemoglobinuria is a rare disease characterised by aplastic anemia, thrombosis and red urine in the morning due to breakdown of red blood cells. Signs and symptoms As the name implies, the hemoglobin appears in urine in attacks (paroxy
- Use of the oral contraceptive pill
- 'Circumstantial'
- Immobilisation, e.g. after-
- SurgerySurgery is the medical specialty that treats diseases or injuries by operative manual and instrumental treatment. Its practitioners are referred to as surgeons''. History of surgery Although surgeons are now considered to be specialised physicians, the pr
- Trauma
- Obesity
- Pregnancy
- Cancer (Trousseau's syndrome)
3 Diagnosis
The diagnosis of pulmonary embolism (PE), suspected on the basis of shortness of breath and chest pain, with or without an abnormal X-ray, can be confirmed by a medical test called a "ventilation-perfusion scan" (or V/Q scan), which shows that some areas of the lung are being ventilated but not perfused with blood (due to obstruction by a clot).
In low/moderate suspicion of PE, a normal ( D-dimer) blood test is enough to exclude the possibility of PE (Bounameaux et al 1994).
Instead of the V/Q scan spiral computed tomography (spiral CT) is increasingly being used, especially when other lung disorders are part of the differential diagnosis.
In massive PE, dysfunction of the right side of the heart can be seen on echocardiography.
Lower limb ultrasound can be used as a surrogate. The presence of deep venous thrombosis is in itself enough to warrant anticoagulation, without requiring the expensive V/Q or spiral CT scans.
