People call it “silent killer” or “sudden death”. Whatever the name, Pulmonary Embolism (PE) is a feared cause of death. According to Wikipedia, 15 per cent of all cases of sudden death are attributable to PE. The diagnosis requires a very high index of suspicion. The common signs include: a sudden onset of shortness of breath, sharp chest pain that gets worse with coughing, low oxygen saturation, and a rapid heart rate. If not recognised and treated quickly, a PE can lead to a lowering of the blood pressure or even sudden death.
According to the current U.S. literature, PE affects more than 600,000 people every year and results in 50-200,000 deaths. The death rate from untreated PE can be as high as 26%. Fortunately, the incidence of PE in America has declined from 6% to 2% over the last 25 years. According to American Journal of Medicine, patient fatality rate is 4.2% while in the hospital and 13.8% at 90 days after discharge.
A pulmonary embolism develops when a blood clot travels to the blood vessels that supply blood to the lungs and blocks the main pulmonary (Lung) artery or one of its branches. Deep venous thrombosis (DVT) or clotting of deep veins in the legs is the primary culprit. Rarer causes include cancer, air bubbles, or fat released in the veins from a bone fracture. Some inherited deficiencies of clotting factors make people more prone to develop blood clots.
Clotting can also be enhanced by inactivity during long flights, recovery from surgery, or medical illnesses like strokes. People taking birth control pills, some hormones, smokers, and obese individuals are also at an increased risk for developing clots and/ or PE. Prevention can include frequent ambulation, ted hose stocking, sequential compressive device and finally subcutaneous injection of blood thinner in hospitalised patients.
Most common test employed for diagnosis is CT scan of chest with IV contrast. Pulmonary Angiogram which used to be the gold standard is considered too invasive for common use. Ventilation/Perfusion of the lung is the second most common test employed. D-dimer is another test used commonly in emergency room setting for screening PE. This test is very sensitive but not very specific for diagnosis. If it is found to be negative, you can be very sure that patient does not have PE. The work-up for PE is also considered when the chest x-ray is clear, while no clear reasons for shortness of breath identified in the appropriate group of patients.
The most common treatment of PE includes medications like intravenous heparin, followed by oral substitutes like Coumadin for 4-6 months or longer. Several new oral drugs are also available to treat this condition. In case heparin or anticoagulants cannot be used, placement of filter in the Inferior vena cava is the next best option.
PE is a serious medical problem that requires extra vigilance for diagnosis. Prompt diagnosis and treatment can save many lives and minimise the cost of care.
[Anis Ansari, MD, is Chairman, Department of Medicine, Mercy Medical Centre, Clinton, Iowa, USA]