Venous thromboembolism (VTE) is a common and deadly disease that includes deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT occurs when blood coagulates inside a deep vein—usually in the leg, but occasionally in the arm or proximal vein. PE occurs when a portion of a clot breaks off and travels to a pulmonary artery. The clinical presentation of VTE is highly variable, thus clinicians must maintain a high index of suspicion.
There are numerous risk factors for VTE including: advanced age, obesity, pregnancy, malignancy, inherited thrombophilia, recent surgery or major trauma, immobility/bed rest, an indwelling central venous catheter, long distance travel, smoking, congestive heart failure, stroke, estrogen use, and inflammatory conditions. The absence of known risk factors does not confer absolute protection from VTE.
Deep vein thrombosis: Classically, DVT presents as calf or leg pain, redness, swelling, tenderness, and warmth. Unfortunately, this constellation of findings is present in fewer than 50% of DVT patients. A difference in lower leg diameter is predictive, but Homan sign (ie, pain in the calf with forced dorsiflexion) is neither sensitive nor specific for DVT. The presence of upper extremity swelling associated with an indwelling venous catheter should raise suspicion of an upper extremity DVT.
Uncommon but severe presentations of DVT include phlegmasia cerulea dolens and phlegmasia alba dolens.Phlegmasia cerulea dolens is a high-grade obstruction that elevates compartment pressures and can compromise limb perfusion. It presents as a massively swollen, cyanotic limb. Phlegmasia alba dolens is usually associated with pregnancy and has a similar pathophysiology but presents as a pale limb secondary to arterial spasm.
Pulmonary embolism: The diagnosis of PE should be considered in any patient who experiences acute dyspnea, chest pain, unexplained tachycardia, hypoxemia, syncope, or shock. The most common symptoms include dyspnea, pleuritic or nonpleuritic chest pain, anxiety, cough, and syncope, though PE can present as confusion or even seizure. Common signs include hypoxemia, tachypnea, tachycardia, hemoptysis, diaphoresis, and low-grade fever. Clinical signs of DVT occur in about 50% of patients with PE. Massive PE can cause hypotension, severe hypoxemia, or cardiopulmonary arrest. However, the clinical presentation of VTE can be insidious; there is poor correlation between the size of a PE and the severity of symptoms. In fact, patients with sizable PE may be asymptomatic.
The leg pain and swelling associated with DVT are similar to that seen with cellulitis, congestive heart failure, musculoskeletal injuries, and venous stasis without thrombosis. The differential diagnosis of PE includes many pulmonary disorders, including: asthma, chronic obstructive pulmonary disease, pleural effusion, pneumonia, and pneumothorax. Cardiac disorders that may mimic PE include angina/myocardial infarction, congestive heart failure, pericarditis, and tachydysrhythmia. Muscle strain and costochondritis can mimic the chest pain of PE. Anxiety and hyperventilationsyndrome may mimic PE but should be considered diagnoses of exclusion.
Pretest probability assessment: The clinician should consider the patient's probability of PE prior to the decision to initiate testing. ...