Rasmussen syndrome atypicalities

Caraballo RH, Valenzuela GR, Pociecha J, Princich JP, Gutierrez R, Beltran L, Lubieniecki F, Bartuluchi M. Rasmussen syndrome: an atypical presentation in ten patients. Epileptic Disord. 2018 Dec 1;20(6):468-478. doi: 10.1684/epd.2018.1007. PMID: 30530407.

Abstract

The aim of this study was to analyse the electroclinical and imaging findings and outcome of patients with Rasmussen syndrome (RS) with atypical manifestations. We conducted a retrospective, descriptive study of 10 of 44 consecutive patients with RS with atypical features, followed between 1999 and 2017. Six patients were boys and four were girls. The mean and median ages at onset of the seizures were 8.8 and 6.5 years, respectively (range: 4.6-13 years). All of the patients except one had seizures. Eight patients (80%) had epilepsia partialis continua that started at a mean age of 7.5 years (range: 7-15 years). In our series, hemiparesis without seizures was the first manifestation in three patients, one of whom had dual pathology. In two patients, the first manifestation was dyskinetic movements, followed by delayed-onset seizures associated with unilateral caudate atrophy. Two patients had a focal lesion mimicking focal cortical dysplasia as the first MRI abnormality; one of these two patients had epileptic spasms in clusters. Bilateral cerebral hemisphere involvement was observed in three patients during the course of the disease. Six of eight patients responded well to surgical treatment. Progressive hemiparesis alone or with delayed-onset seizures, dyskinetic movements associated with seizures, a focal lesion mimicking focal cortical dysplasia, and bilateral brain involvement were the atypical features recognized. Our series of patients responded well to surgery. Clinical, video-EEG, and neuroradiological follow-up is important for early confirmation of RS in order to initiate adequate management of the condition.

Olson HE, Lechpammer M, Prabhu SP, Ciarlini PD, Poduri A, Gooty VD, Anjum MW, Gorman MP, Loddenkemper T. Clinical application and evaluation of the Bien diagnostic criteria for Rasmussen encephalitis. Epilepsia. 2013 Oct;54(10):1753-60. doi: 10.1111/epi.12334. Epub 2013 Aug 23. PMID: 23980696.

Abstract

Purpose: The 2005 diagnostic criteria for Rasmussen encephalitis (RE) are based on seizures, clinical deficits, electroencephalography (EEG), neuroimaging, and pathology (Brain, 128, 2005, 451). We applied these criteria to patients evaluated for RE and epilepsy surgery controls to determine the sensitivity, specificity, and positive and negative predictive values (PPVs, NPVs) using pathology as the gold standard.

Methods: We identified patients evaluated for RE based on medical records from 1993 to 2011. Fifty-two control patients with refractory epilepsy, unilateral magnetic resonance imaging (MRI) changes, and biopsies were selected from an epilepsy surgery database from matching years. Patients meeting all three of group A and/or two of three group B criteria were classified as meeting full criteria (positive). Patients not meeting full criteria were classified as negative. When available, pathology findings were re-reviewed with neuropathologists, and MRI imaging was re-reviewed with a neuroradiologist.

Key findings: RE was considered in the differential diagnosis for 82 patients, of whom 35 had biopsies. Twenty patients met full criteria (positive) without another explanation, including seven for whom biopsy was required to meet criteria and one in whom another etiology was identified. Two patients met full criteria but had another explanation. Thirty-five met partial criteria (negative), of whom 14 had another etiology identified. Twenty-five met no criteria (negative). The diagnostic criteria had a sensitivity of 81% with four false negatives (criteria-negative, biopsy-positive) when compared to pathology as a gold standard. Five false positives (criteria positive, biopsy negative) had identifiable alternate diagnoses.

Significance: The 2005 Bien clinical diagnostic criteria for RE have reasonably high sensitivity and specificity and good clinical-pathologic correlation in most cases. We suggest modification of the criteria to allow inclusion of cases with well-described but less common features. Specifically we suggest making the diagnosis in the absence of epilepsia partialis continua (EPC) or clear progression of focal cortical deficits or MRI findings if biopsy is positive and two of the A criteria are met (B3 plus two of three A criteria). This would improve the sensitivity of the criteria.