Table 1.
Clinical and Radiological Features of Delayed Relapsing-Remitting Radiotherapy-Induced Neurologic Syndromes (Adapted From 68 and 70)
| SMART syndrome | PIPG | ALERT syndrome | |
|---|---|---|---|
| Clinical symptoms |
|||
| Seizures | Frequently, mostly generalized seizures | Very frequently, mostly partial seizures, including subclinical epileptic discharges | Rare |
| Headache | Constant, migraine-like attacks | No | No |
| Others | Stroke-like deficits | Postictal deficits | Encephalopathy |
| MRI findings T1-weighted imaging with gadolinium |
Diffuse unilateral cortical (parieto-occipital) gadolinium enhancement of cerebral gyri | Focal cortical and/or leptomeningeal enhancing lesions | Bilateral cortico-subcortical multiple patchy enhancement ± leptomeningeal enhancement |
| Treatment | Symptomatic (headache treatment) | Symptomatic (antiepileptic drugs) | High doses of corticosteroids |
| Clinical course | Full recovery within d to few wk; relapses possible | Full recovery within wk to few mo; relapses possible | Full recovery in wk, sometimes need intensive care unit, relapses possible |
Abbreviations: ALERT, acute late-onset encephalopathy after radiotherapy; PIPG, peri-ictal pseudoprogression; SMART, stroke-like migraine attacks after radiation therapy.