Overview
Definition:
Venous thromboembolism (VTE) in adolescents encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE), serious conditions involving abnormal blood clot formation in veins, leading to obstruction of blood flow.
Epidemiology:
While historically considered rare in children, the incidence of VTE in adolescents is increasing, estimated to be between 0.1 to 0.5 per 10,000 person-years, with significant morbidity and mortality
Risk factors include acquired conditions such as malignancy, infection, trauma, surgery, central venous catheters, and inherited thrombophilias.
Clinical Significance:
Untreated or inadequately managed VTE in adolescents can lead to significant short-term complications like post-thrombotic syndrome and pulmonary hypertension, and long-term sequelae including recurrent VTE, chronic venous insufficiency, and potentially fatal pulmonary embolism
Early diagnosis and appropriate anticoagulation are crucial for optimal outcomes and reducing long-term burden.
Clinical Presentation
Symptoms:
DVT symptoms include unilateral limb swelling, pain, warmth, redness, and tenderness
PE symptoms can include sudden onset dyspnea, pleuritic chest pain, cough (sometimes with hemoptysis), tachypnea, and tachycardia
Neonates may present with different signs like cyanosis, lethargy, or abdominal distension.
Signs:
Physical findings in DVT may include palpable venous cord, edema, erythema, and increased warmth over the affected limb
Signs of PE can include tachypnea, tachycardia, hypoxia, hypotension, and a new or worsened murmur
Examination of the central venous catheter site is important in those with catheters.
Diagnostic Criteria:
There are no universally established diagnostic criteria for VTE in adolescents specifically, but clinical decision rules like the Wells score (modified for pediatrics) or revised Geneva score, combined with D-dimer levels and imaging, guide the workup
Extensive thrombophilia testing is reserved for recurrent VTE or strong family history.
Diagnostic Approach
History Taking:
Key history points include presence of risk factors: malignancy, infection, inflammatory bowel disease, nephrotic syndrome, recent surgery or trauma, immobilization, family history of VTE, thrombophilia, presence of central venous catheters, or use of hormonal therapies
Screen for symptoms of DVT and PE.
Physical Examination:
A thorough physical exam should assess for unilateral limb swelling, edema, tenderness, erythema, warmth in suspected DVT
For suspected PE, evaluate vital signs (heart rate, respiratory rate, oxygen saturation, blood pressure), listen for heart and lung sounds, and assess for signs of deep vein thrombosis.
Investigations:
Initial investigations may include complete blood count (CBC), coagulation profile (PT, aPTT, INR), D-dimer assay (elevated in VTE but nonspecific in children, especially with inflammation)
Imaging: For DVT, Doppler ultrasonography is the gold standard
For PE, CT pulmonary angiography (CTPA) is preferred in hemodynamically stable patients
V/Q scan may be used if CTPA is contraindicated
Echocardiography can assess for right heart strain.
Differential Diagnosis:
For DVT, differentials include cellulitis, musculoskeletal injury, superficial thrombophlebitis, lymphatic obstruction, and Baker's cyst
For PE, differentials include pneumonia, asthma exacerbation, pneumothorax, pericarditis, anxiety, and musculoskeletal chest pain
Septic thrombophlebitis is also a consideration.
Management
Initial Management:
Immediate management focuses on anticoagulation to prevent clot extension and propagation
Hemodynamically unstable patients with PE may require thrombolysis or embolectomy.
Medical Management:
Anticoagulation is the mainstay
Options include unfractionated heparin (UFH) infusion with target aPTT of 1.5-2.5 times control
low-molecular-weight heparin (LMWH) like enoxaparin (pediatric dosing based on weight, e.g., 1 mg/kg twice daily or 1.5 mg/kg once daily)
or fondaparinux
Warfarin can be initiated concurrently with LMWH/UFH, aiming for an INR of 2.0-3.0 once therapeutic, with a minimum duration of 3 months
Newer direct oral anticoagulants (DOACs) like rivaroxaban and apixaban are increasingly used in adolescents, with specific weight-based dosing protocols, but long-term safety data is still evolving.
Surgical Management:
Surgical intervention is rare and reserved for severe cases of DVT or PE with life-threatening consequences
Options include pharmacomechanical thrombolysis for extensive iliofemoral DVT, and surgical or catheter-directed embolectomy for massive PE causing hemodynamic instability
Inferior vena cava (IVC) filters are rarely indicated in children due to high complication rates.
Supportive Care:
Supportive care includes pain management, limb elevation, and compression stockings for DVT to reduce post-thrombotic syndrome risk
For PE, oxygen therapy, bronchodilators if bronchospasm, and cardiovascular support are essential
Close monitoring for bleeding complications of anticoagulation is critical.
Complications
Early Complications:
Early complications include bleeding from anticoagulation, extension of thrombosis, recurrent VTE, and in PE, hemodynamic compromise or death
Post-thrombotic syndrome can begin to develop within weeks to months.
Late Complications:
Long-term complications include chronic post-thrombotic syndrome with venous insufficiency (pain, swelling, skin changes, ulcers), and pulmonary hypertension secondary to recurrent or unresolved PE
Increased risk of recurrent VTE.
Prevention Strategies:
Strategies include prophylactic anticoagulation in high-risk adolescent patients (e.g., those with malignancy, undergoing major surgery, or with indwelling central venous catheters), judicious use of central venous catheters, prompt removal of catheters when no longer needed, and patient education on recognizing symptoms of VTE.
Prognosis
Factors Affecting Prognosis:
Prognostic factors include the extent of VTE, presence of underlying malignancy or severe comorbid conditions, initiation of anticoagulation, development of complications like pulmonary hypertension or post-thrombotic syndrome, and adherence to treatment
Recurrence rates can be significant.
Outcomes:
With appropriate anticoagulation, most adolescents with VTE have a good short-term outcome, with reduction in clot extension and resolution of symptoms
However, a significant proportion will experience long-term sequelae such as post-thrombotic syndrome
Recurrence rates vary but can be up to 10-20% over 5 years.
Follow Up:
Long-term follow-up is essential to monitor for recurrent VTE, development or progression of post-thrombotic syndrome, and pulmonary hypertension
This typically involves regular clinical assessments, Doppler ultrasound of affected limbs, and echocardiography as indicated
Duration of anticoagulation is individualized, often ranging from 3 months to lifelong, based on risk factors and recurrence.
Key Points
Exam Focus:
Remember increasing incidence of VTE in adolescents, common risk factors (central lines, malignancy, surgery), diagnostic modalities (Doppler US for DVT, CTPA for PE), and anticoagulation choices (LMWH, UFH, Warfarin, DOACs) with pediatric dosing considerations
Differentiate DVT/PE symptoms and initial management
Post-thrombotic syndrome and pulmonary hypertension are key long-term sequelae.
Clinical Pearls:
Always consider VTE in an adolescent with unexplained limb swelling/pain or sudden onset dyspnea/chest pain, especially if they have significant risk factors
D-dimer can be helpful but needs to be interpreted in context
a normal result can help rule out VTE in low-risk individuals
Pediatric dosing of anticoagulants is critical and often weight-based.
Common Mistakes:
Underestimating VTE risk in adolescents
Delaying diagnosis due to attributing symptoms to less serious causes
Inadequate anticoagulation duration or dosage
Failure to monitor for bleeding complications
Not considering thrombophilia workup in select cases of recurrent VTE or strong family history.