Can Dermatomyositis Cause Seizures?
Dermatomyositis can cause seizures, but this is a rare and life-threatening complication that occurs primarily in juvenile dermatomyositis (JDM) through central nervous system (CNS) vasculopathy, with a mortality rate approaching 67% when CNS involvement occurs.
Epidemiology and Risk Profile
- CNS involvement with seizures occurs in approximately 1% of hospitalized JDM patients, making it an uncommon but critical complication 1
- This complication typically manifests within the first 10 months of disease onset 1
- The mortality rate for JDM patients with CNS involvement is 66.6%, making early recognition essential for survival 1
- CNS complications are rarely reported in adult-onset dermatomyositis, though they can occur 2
Clinical Presentation and Associated Features
When seizures occur in dermatomyositis, they are typically accompanied by specific warning signs:
- Active cutaneous vasculopathy is the most consistent associated finding 1
- Severe proximal muscle weakness often coexists with neurological symptoms 1
- Hyperferritinemia and thrombocytopenia are common laboratory abnormalities 1
- Anti-NXP2 antibody positivity has been documented in affected patients 1
Pathophysiologic Mechanisms
The underlying pathology involves two distinct presentations:
- Cerebral vasculitis affecting CNS blood vessels 1
- Cerebral macrophage activation syndrome, a severe systemic inflammatory condition 1
- The systemic vasculopathy characteristic of dermatomyositis can extend to CNS vessels, though this is under-recognized 2
Critical Management Considerations
Immediate aggressive immunosuppression is required when CNS involvement is suspected:
- Intravenous methylprednisolone (IVMP) pulse therapy should be initiated urgently 1
- Plasma exchange may be necessary as salvage therapy 1
- Both patients who survived in the recent case series achieved complete neurological recovery with aggressive treatment 1
- Delayed recognition and treatment significantly increases mortality risk 1
Important Clinical Pitfalls
- CNS involvement is easily missed because it is not included in standard dermatomyositis complication screening protocols outlined in major guidelines 3, 4
- The major guidelines focus on interstitial lung disease, cardiac involvement, and malignancy screening but do not specifically address CNS complications 3, 4
- Seizures may be accompanied by pseudoseizures and psychiatric symptoms like depression, complicating diagnosis 2
- Brainstem involvement can be rapidly fatal 2
Contrast with Standard Dermatomyositis Complications
While guidelines emphasize monitoring for interstitial lung disease (present in ~8% of patients), cardiac involvement, and malignancy 3, 4, CNS involvement represents a distinct and more immediately life-threatening complication that requires different management. The standard complications listed in comprehensive dermatomyositis reviews do not typically include seizures as a primary manifestation 5, 6, 7.
In clinical practice, any dermatomyositis patient—particularly children—presenting with new-onset seizures and active cutaneous vasculitis should be treated as a medical emergency requiring immediate aggressive immunosuppression, as this represents one of the few potentially reversible causes of mortality in this disease.