A 28-year-old woman with SLE presents with a new onset seizure. Which is the most common cause of seizures in SLE patients?

Explanation

## Most Common Cause of Seizures in SLE **Key Point:** Metabolic derangements — particularly uremia from active lupus nephritis, hyponatremia, and hypoglycemia — are collectively the **most common** identifiable cause of seizures in SLE patients, accounting for the majority of acute seizure episodes in large cohort studies. ### Pathophysiology of Metabolic Seizures in SLE 1. **Lupus nephritis** (Class III–V) → progressive renal impairment → uremia → lowered seizure threshold 2. **Hyponatremia** from nephrotic syndrome, SIADH, or diuretic use → neuronal swelling → cortical hyperexcitability 3. **Hypoglycemia** from corticosteroid-induced insulin dysregulation 4. **Hypertensive encephalopathy** from renal hypertension — a closely related metabolic/vascular mechanism ### Causes of Seizures in SLE (Evidence-Based Frequency) | Cause | Relative Frequency | Mechanism | |-------|-------------------|-----------| | **Metabolic derangement (uremia, hyponatremia, hypoglycemia)** | **Most common** | Active nephritis, medications, fluid shifts | | Antiphospholipid antibody-associated thrombosis | Common | Hypercoagulability → ischemic stroke | | Cerebral vasculitis / infarction | Less common than previously thought | Direct vessel inflammation | | Lupus anticoagulant-mediated CVST | Uncommon (<5%) | Venous thrombosis | **Clinical Pearl:** True cerebral vasculitis (histologically confirmed) is actually rare in SLE; what was historically labeled "lupus cerebral vasculitis" is now understood to be predominantly a non-inflammatory vasculopathy or antiphospholipid-mediated thrombosis. Metabolic causes remain the most frequent and most reversible trigger for seizures in SLE (Harrison's Principles of Internal Medicine, 21st ed.; Hahn BH, *Dubois' Lupus Erythematosus*, 8th ed.). **High-Yield:** In the NEET PG / INI-CET context, metabolic derangement (especially uremia from lupus nephritis) is cited as the **most common** cause of seizures in SLE. Antiphospholipid syndrome is the most common cause of **recurrent** thrombotic neurological events, but not of seizures overall. **Tip:** When evaluating seizures in SLE, always check: - Serum electrolytes (Na⁺, glucose, BUN, creatinine) - Blood pressure (hypertensive encephalopathy) - MRI brain (ischemic lesions, PRES pattern) - Antiphospholipid panel (aCL, anti-β2GPI, lupus anticoagulant) - Complement levels (C3, C4) and anti-dsDNA titers