Venous thromboembolism (VTE) includes deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT occurs when blood coagulates inside a deep vein such as those in the leg, arm, or pelvis. Most PEs occur when a portion of a venous clot breaks off, travels through the venous system through the right side of the heart, and subsequently enters a pulmonary artery. The clinical presentation of VTE is highly variable, thus clinicians must maintain a high index of suspicion for the diagnosis. Mortality from VTE is variable, with case fatality rates ranging from 1% to 45%, depending on the clinical presentation and comorbid conditions.
There are numerous factors that affect the risk of VTE and the clinical presentation. Factors that increase the risk of VTE include advanced age, obesity, pregnancy, prior VTE, malignancy, inherited thrombophilia, recent surgery or major trauma, immobility, an indwelling central venous catheter, smoking, long-distance travel, congestive heart failure, stroke, estrogen use, and inflammatory conditions.
Patients with lower extremity DVT often present with calf or leg pain, redness, swelling, tenderness, and warmth. Patients with upper extremity DVT, which often occurs in the setting of an indwelling catheter, present with similar symptoms in an upper extremity. This classic constellation of findings is present in fewer than 50% of DVT patients, and while a 2-cm difference in lower leg circumference is predictive, pain in the calf with forced dorsiflexion of the foot (Homans’ sign) is neither sensitive nor specific for DVT.
Uncommon but severe presentations of DVT include phlegmasia cerulea dolens and phlegmasia alba dolens. Phlegmasia cerulea dolens presents as an extremely swollen and cyanotic limb due to a high-grade obstruction that elevates compartment pressures and can compromise limb perfusion. Phlegmasia alba dolens has a similar pathophysiology but presents as a pale limb secondary to arterial spasm.
The clinical presentation of PE is highly variable, ranging from sudden death to incidental diagnosis in patients who are completely asymptomatic. Consider the possibility of PE in a patient who experiences acute dyspnea, pleuritic chest pain, unexplained tachycardia, hypoxemia, syncope, or shock—especially in the absence of physical examination or radiographic findings for alternative diagnoses. The most common symptoms of an acute PE are dyspnea and pleuritic chest pain. Syncope occurs in 3% to 4% of patients with PE, which can be accompanied by convulsions or seizures. Physical findings that may accompany a PE 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 and there may be poor correlation between the size of a PE and the severity of symptoms.
DIAGNOSIS AND DIFFERENTIAL