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Clinical Presentation
Deep Vein Thrombosis
The signs and symptoms suggestive of deep vein
thrombosis include localized tenderness along the distribution of the deep
venous system, swelling on a unilateral or an entire leg, calf swelling >3
cm compared to an asymptomatic leg (measured 10 cm below tibial tuberosity), pitting
edema that is greater in the symptomatic leg, collateral superficial veins
(non-varicose), erythema, warmth, and superficial thrombophlebitis with a
palpable cord over a superficial vein.
Phlegmasia cerulea dolens (blue leg) happens when deoxygenated
hemoglobin in the stagnant veins causes a cyanotic hue in the leg. It is seen
in severe forms of iliocaval or iliofemoral deep vein thrombosis causing total
outflow obstruction with rapid extension of thrombosis into all deep and
superficial veins, including collaterals over a few hours leading to sudden
severe ischemic pain, massive limb congestion, cyanosis, loss of function,
tachycardia, and shock.
Phlegmasia alba dolens (pale, white, or milk leg) is
the presence of pallor in the edematous legs and is due to the interstitial
tissue pressure exceeding the capillary perfusion pressure. It is commonly seen
in patients with thrombus in the major deep veins.
Pulmonary
Embolism
The suspicion of pulmonary embolism is usually
raised by the clinical symptoms. Clinical findings are nonspecific and should
not be the only criteria to diagnose pulmonary embolism. Dyspnea, pleuritic
chest pain, syncope, and tachypnea (respiratory rate ≥20/minute) occur in most
cases of pulmonary embolism.
Dyspnea is the most frequent symptom, while
tachypnea is its most frequent sign. Other signs and symptoms that may be
present include tachycardia (heart rate >100/minute), cough and hemoptysis,
fever, diaphoresis, nonpleuritic chest pain, apprehension, rales, increasing
pulmonic component of the second heart sound, wheezing, hypotension, cyanosis,
pleural rub, and raised jugular venous pressure. Pulmonary embolism should be
suspected in cases of postoperative hypoxemia.
Pleuritic chest pain with or without dyspnea is one
of the most frequent presentations of pulmonary embolism. It may suggest a
small embolism located distally near the pleura that also causes pleural
irritation.
Isolated dyspnea may occur suddenly or progressively
(over several weeks). It is usually due to a more central pulmonary embolism (not
affecting the pleura). It may be associated with substernal angina-like chest
pain that probably represents right ventricular (RV) ischemia. Worsening
dyspnea may be the only symptom that indicates pulmonary embolism in patients with
preexisting heart failure or pulmonary disease.
Syncope or shock is the hallmark sign of central pulmonary
embolism and usually results in severe hemodynamic repercussions. The signs of
hemodynamic compromise and reduced heart flow are also usually present (eg
systemic arterial hypotension, oliguria, cold extremities, and/or clinical
signs of acute right heart failure).
Massive
Pulmonary Embolism
Massive pulmonary embolism accounts for 5 to 10% of
cases. Dyspnea is usually the prime symptom and systemic arterial hypotension
that requires pressor support is the predominant sign. Persistent hypotension
is defined as a systolic BP (SBP) of <90 mmHg or a pressure drop of at least
40 mmHg from baseline for at least 15 minutes (or needing inotropic support)
not caused by new-onset arrhythmia, hypovolemia or sepsis; or absence of pulse,
or sustained heart rate <40 beats/minute (bpm) with signs or symptoms of
shock. Syncope and altered mentation, renal insufficiency, hepatic dysfunction,
and severe respiratory distress or hypoxemia (eg cyanosis) may also be present.
In patients with suspected massive pulmonary
embolism who are too unstable for lung imaging, right ventricular dysfunction
can usually be found at the bedside with findings of left parasternal heave,
distended jugular veins, and systolic murmur of tricuspid regurgitations that
increases with inspiration.
Sub-massive
Pulmonary Embolism
Sub-massive pulmonary embolism occurs in
approximately 20 to 25% of patients. It is a subgroup of non-massive pulmonary
embolism patients who present with normal blood pressure, normal tissue
perfusion, and clinical or echocardiographic evidence of right ventricular
dysfunction or myocardial necrosis. Patients may present with elevated
troponin, N-terminal pro B-type natriuretic peptide (NT-proBNP), or BNP.
Low-Risk
Pulmonary Embolism
Low-risk pulmonary embolism affects approximately
70% of patients with pulmonary embolism. It is a pulmonary embolism that
presents with normal systemic arterial pressure and right ventricular function,
without elevated cardiac biomarkers. Patients with suspected or confirmed
low-risk pulmonary embolism may be considered for outpatient treatment after
clinical assessment and after being determined suitable using a validated risk
stratification tool.
Diagnosis or Diagnostic Criteria
Clinical findings are
important in the diagnosis of deep vein thrombosis but are poor predictors of
the presence or severity of thrombosis. Pretest probability is needed to guide
the diagnostic process.
| WELLS SCALE OF CLINICAL PRETEST PROBABILITY FOR DEEP VEIN THROMBOSIS | |||
| Clinical Features | Points | Pretest Total Probability Points |
|
| Entire leg swollen | 1.0 | High risk≥3 Moderate risk1-2 Low risk≤0 If both legs are symptomatic, score the more severe side Simplified version*: Likely≥2 Unlikely<2 |
|
| Calf swollen by >3 cm compared to the asymptomatic side (measured 10 cm below tibial tuberosity) | 1.0 | ||
| Localized tenderness along the deep venous system distribution | 1.0 | ||
| Pitting edema (greater in the symptomatic leg) | 1.0 | ||
| Collateral superficial veins (non-varicose) | 1.0 | ||
| Immobilization for >3 days or major surgery within 12 weeks | 1.0 | ||
| Paralysis, paresis, recent plaster immobilization of lower extremity | 1.0 | ||
| Previously documented DVT | 1.0 | ||
| Active cancer (ongoing treatment within the last 6 months or current palliative therapy) | 1.0 | ||
| Alternative diagnosis as likely or greater than that of DVT | -2.0 | ||
| Reference: Institute for Clinical Systems Improvement. Health care guideline: venous thromboembolism diagnosis and treatment. 13th ed. Jan 2013. *National Institute for Health and Care Excellence (NICE). Venous thromboembolic diseases: diagnosis, management and thrombophilia testing. https://www.nice.org.uk. 26 Mar 2020. |
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Pretest Probability of Pulmonary
Embolism
All patients with possible pulmonary embolism should
have their clinical probability assessed and documented. Clinical probability
may be estimated empirically or explicitly by a prediction rule. There are 2
frequently used pretest probabilities of pulmonary embolism which are the
Geneva score (Europe) and Wells scale (Canadian rule).
Geneva
Score
Geneva score requires arterial blood gas measurement
and a chest radiograph.
| GENEVA CLINICAL PREDICTION RULE FOR PULMONARY EMBOLISM | |||||
| Clinical Features | Points | Simplified Version | Pretest Total Probability Points |
Simplified Version | |
| Age >65 years | 1 | 1 | Based on likelihood of PE PE likely≥6 PE less likely0-5 According to risk groups High≥11 Intermediate4-10 Low0-3 |
≥3 0-2 ≥5 2-4 0-1 |
|
| Active cancer | 2 | 1 | |||
| Fracture or surgery within the past month | 2 | 1 | |||
| Heart rate 75-94 bpm ≥95 bpm |
3 5 |
1 2 |
|||
| Hemoptysis | 2 | 1 | |||
| Previous DVT or PE | 3 | 1 | |||
| Unilateral edema and pain on lower-limb deep venous palpation | 4 | 1 | |||
| Unilateral pain in lower limb | 3 | 1 | |||
| Reference: 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS): The Task Force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC). Eur Respir J. 2019 Aug 31. | |||||
Wells Scale
Wells scale requires that the patient has clinical features suggestive of pulmonary embolism (eg breathlessness, and/or tachypnea with or without pleuritic chest pain and/or hemoptysis), along with 2 other features, the absence of another reasonable clinical explanation and the presence of a major risk factor.
| WELLS SCALE OF CLINICAL PRETEST PROBABILITY FOR PULMONARY EMBOLISM | |||
| Clinical Features | Points | Simplified Version* | Pretest Total Probability Points |
| Clinical signs and symptoms of DVT | 3.0 | 1 | Based on likelihood of PE PE likely>4 PE less likely≤4 According to risk groups High>6 Intermediate2-6 Low<2 Simplified version*: Likely≥2 Unlikely<2 |
| Alternative diagnosis is less likely than PE | 3.0 | 1 | |
| Heart rate ≥100 bpm | 1.5 | 1 | |
| Immobilization for ≥3 days or surgery within the past 4 weeks | 1.5 | 1 | |
| Previous DVT/PE | 1.5 | 1 | |
| Hemoptysis | 1.0 | 1 | |
| Malignancy (with treatment within the last 6 months) | 1.0 | 1 | |
| Reference: Institute for Clinical Systems Improvement. Health care guideline: venous thromboembolism diagnosis and treatment. 13th ed. Jan 2013. *2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS): The Task Force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC). Eur Respir J. 2019 Aug 31. |
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Pulmonary Embolism Rule-Out Criteria (PERC)
PERC is used to identify groups at very low risk of pulmonary embolism and to determine if additional investigations for pulmonary embolism are warranted.
If the patient has answered yes to any of the following questions, the patient is PERC positive:
- Is the patient >49 years?
- Is the patient’s heart rate >99 bpm?
- Is the patient’s pulse oximetry reading <95% while breathing room air?
- Does the patient have hemoptysis?
- Is the patient on exogenous estrogen?
- Does the patient have prior diagnosis of VTE?
- Has the patient had surgery or trauma in the previous 4 weeks?
- Does the patient have unilateral leg swelling at the calves?
In selected patients, PE can be ruled out without imaging tests or D-dimer if PERC is negative.