Venous Sinus Thrombosis in Pediatric SLE
Venous sinus thrombosis (also called cerebral venous sinus thrombosis or CVST) is a blood clot formation in the dural venous sinuses that drain blood from the brain, causing elevated venous pressure, increased intracranial pressure, and potentially venous infarction with or without hemorrhage. 1
Pathophysiology in SLE Context
In an 11-year-old with SLE, CVST occurs through two primary mechanisms:
- Vasculitis-mediated injury: Immune complex deposition causes endothelial cell damage in cerebral venous structures, which is the predominant mechanism when antiphospholipid antibodies are absent 2, 3
- Hypercoagulable state: SLE creates enhanced coagulability through multiple pathways, with or without antiphospholipid antibodies 1, 4
- SLE is recognized as an uncommon but established cause of CVST, particularly in active disease states 1
Clinical Presentation Specific to This Population
The 11-year-old patient may present with:
- Headache (88% of cases): Typically diffuse and progressive over days to weeks, though can be acute 1, 3
- Increased intracranial pressure signs (76.5% in SLE-CVST): Papilledema, sixth nerve palsy causing diplopia, nausea/vomiting 1, 3
- Focal neurological deficits: Seizures (35%), hemiparesis, aphasia, or other cortical signs depending on location of venous infarction 1, 3
- Ocular manifestations (35%): Eyelid/conjunctival edema, blurred vision, diplopia 3
- Altered consciousness (41%) in more severe cases 3
Critical pitfall: Up to 25% present with isolated headache without focal signs, making diagnosis challenging and easily missed 1
Anatomic Distribution
- Lateral (transverse) sinuses are most commonly affected (73-82%), followed by sigmoid sinus (53%) and superior sagittal sinus (35%) 1, 3
- Multiple sinus involvement occurs in 70.6% of SLE-CVST cases, which is higher than general CVST populations 3
Complications
- Hemorrhagic infarction occurs in 48% of older children (versus 72% in neonates) 1
- Hydrocephalus complicates 10% of cases 1
- Increased intracranial pressure is present in 76.5% of SLE-CVST patients 3
Diagnostic Approach
MRI with MR venography (MRV) is the preferred initial imaging modality for suspected CVST in this patient 1, 5:
- Sensitivity and specificity: Gradient-echo T1-weighted post-contrast MRI shows 92.5% sensitivity and 100% specificity for detecting thrombus 1
- MRV findings: Shows non-filling of affected sinuses; contrast-enhanced MRV is less susceptible to flow artifacts than non-contrast techniques 1
- MRI parenchymal findings: T2 prolongation indicating venous congestion, hemorrhagic infarction, or edema 1
If MRI/MRV is unavailable or contraindicated, CT venography (CTV) is the alternative 1, 5:
A negative plain CT or MRI does not rule out CVST; venographic study (CTV or MRV) must be performed if clinical suspicion remains 1
SLE-Specific Risk Factors in This Patient
Compared to SLE patients without CVST, those with CVST demonstrate 3:
- Higher disease activity (elevated SLEDAI scores)
- Higher prevalence of thrombocytopenia
- Higher prevalence of positive antiphospholipid antibodies
However, antiphospholipid antibodies are absent in many SLE-CVST cases, emphasizing vasculitis as the primary mechanism 4, 2
Additional Pediatric Considerations
- CVST shows bimodal age distribution with peaks in infancy (20%) and adolescence (50% in ages 11-18) 5
- Prothrombotic disorders are found in one-third to two-thirds of pediatric CVST cases 1
- Iron deficiency anemia with microcytosis and thrombocytosis can be associated risk factors in children, though may be obscured by acute-phase hemoconcentration 1
Prognosis
- Early diagnosis and aggressive treatment are essential for favorable outcomes 4, 6, 3
- Mortality occurred in 3 of 17 cases (17.6%) in one SLE-CVST series, emphasizing the serious nature of this complication 3
- Most patients achieve improvement with appropriate treatment combining immunosuppression and anticoagulation 7, 4, 3