What is the primary treatment approach for pediatric patients with Lemierre's syndrome, a condition characterized by thrombophlebitis of the internal jugular vein (IJV) and secondary erythrocytosis, in the presence of underlying cardiac defects, such as patent foramen ovale (PFO)?

Lemierre Syndrome in Children

Primary Treatment Approach

Pediatric patients with Lemierre's syndrome require immediate broad-spectrum antibiotic therapy targeting anaerobic organisms (particularly Fusobacterium necrophorum), combined with anticoagulation using LMWH or UFH for the internal jugular vein thrombophlebitis, with surgical intervention reserved for complications such as abscess drainage or persistent septic emboli. 1, 2

Antibiotic Therapy

• Initiate empiric broad-spectrum antibiotics immediately upon clinical suspicion, targeting anaerobic coverage (particularly Fusobacterium necrophorum in 66.2% of cases) as well as Staphylococcus aureus and other aerobic pathogens 2, 3
• Continue antibiotic therapy for 6-9 weeks depending on severity and complications, with most uncomplicated cases requiring 6 weeks 1, 4
• Blood cultures, tissue cultures, or purulent fluid cultures should guide definitive antibiotic selection, though treatment should not be delayed pending culture results 1

Anticoagulation Strategy

Anticoagulation is recommended in the majority of pediatric Lemierre's syndrome cases despite ongoing debate about its role:

• Use LMWH or UFH as initial anticoagulation for the jugular vein thrombophlebitis, following general pediatric VTE guidelines 5
• Current practice patterns show 63.9% of cases receive anticoagulation at some point during treatment 2
• Continue anticoagulation for a minimum of 3 months, with consideration for extension to 6 months if thrombus persists or complications develop 5, 1
• In the single-institution pediatric series, 89% received anticoagulation for a median duration of 3 months (range 7 weeks to 1 year) with no major hemorrhage complications 1

LMWH Dosing Specifics

• Enoxaparin 1.0 mg/kg subcutaneously every 12 hours for children, adjusted to maintain anti-factor Xa levels between 0.5-1.0 units/mL measured 4 hours post-injection 6
• Newborns require higher doses averaging 1.6 mg/kg every 12 hours due to increased clearance 6
• Monitor anti-Xa levels twice weekly after initial dose adjustment 6

Management of Cardiac Defects (PFO)

For children with Lemierre's syndrome and documented right-to-left shunts such as patent foramen ovale:

• Surgical closure of the PFO should be considered after the acute thrombotic event is stabilized, particularly if paradoxical embolism is suspected 5
• This recommendation applies specifically to arterial ischemic stroke secondary to cardioembolic causes with demonstrated right-to-left shunts 5
• Continue anticoagulation with LMWH or VKAs for at least 3 months while evaluating for PFO closure 5

Thrombophilia Considerations

All children with Lemierre's syndrome should undergo comprehensive hypercoagulability testing:

• 100% of tested children in one series demonstrated thrombophilia, consisting principally of antiphospholipid antibodies and elevated factor VIII activity 1
• The inflammatory prothrombotic state is often characterized by these acquired thrombophilic markers 1
• Testing should include: protein C, protein S, antithrombin III, antiphospholipid antibodies (lupus anticoagulant, anticardiolipin), factor VIII levels, and genetic mutations (factor V Leiden, prothrombin G20210A) 5

Surgical Intervention

Surgical drainage is indicated for:

• Peritonsillar or parapharyngeal abscesses that do not respond to antibiotics alone 4
• Persistent septic emboli despite medical management 7
• Complications such as subdural empyemas or cavernous sinus thrombosis 4
• In severe cases, ligation of the external jugular vein may be necessary 4

Monitoring and Follow-up

• Serial imaging is essential to assess thrombus resolution, as 38% of anticoagulated children showed persistent JVT at 3-6 months 1
• Chest imaging should be performed to evaluate for septic pulmonary emboli, present in the majority of cases 1, 2
• If thrombus persists after 3 months of anticoagulation, extend therapy for an additional 3 months 5

Critical Pitfalls to Avoid

• Do not withhold anticoagulation due to fear of bleeding in the setting of septic thrombophlebitis, as the thrombotic risk outweighs bleeding risk in this population 1
• Do not stop anticoagulation prematurely before 3 months minimum, as persistent vascular occlusion is common 1
• Do not delay treatment while awaiting culture results, as timing is crucial for optimal outcomes 4
• Do not use DOACs (rivaroxaban, apixaban) in children with confirmed antiphospholipid antibodies, as they are associated with excess thrombotic events compared to warfarin 8

Prognosis

• With aggressive antimicrobial and antithrombotic therapy, survival is excellent with no mortality reported in recent pediatric series 1
• No major hemorrhage complications occurred with anticoagulation in the largest pediatric series 1
• However, chronic complications including persistent vascular occlusion occur in approximately 38% despite anticoagulation 1
• Recurrent VTE is rare with appropriate treatment duration 1