[Leber hereditary optic neuropathy: differential diagnosis]. / Neuropathie optique héréditaire de Leber : le diagnostic différentiel.

The diagnosis of Leber hereditary optic neuropathy is suspected in the siblings of an affected person that complains of a decrease in visual acuity. It can also be suspected in a young subject, especially a male, with no medical history that presents with an optic neuropathy. Leber hereditary optic neuropathy is a diagnosis of exclusion. The search for differential diagnoses is essential in all cases, even when a mutation of the mitochondrial DNA was found in the patient of in a healthy carrier maternal relative. This is the interest of multimodal imaging and electrophysiology that allow to exclude retinal pathology mimicking optic neuropathy. A neuroradiological assessment must be systematically prescribed to eliminate a compressive lesion and/or intracranial hypertension. This assessment also provides information on a possible hypersignal of the optic nerve, the appearance of which can be an argument for orientation towards different causes of optic neuritis. Finally, a deficiency or toxic cause must be ruled out.

[Clinical and epidemiological features in Neuromyelitis Optica Spectrum Disorder]. / Comparaison clinico-épidémiologique des pathologies du spectre des neuromyélites optiques.

INTRODUCTION: Neuromyelitis optica spectrum disorder (NMO-SD) has been recognized for the past decade. Biomarkers such as anti-Aquaporin 4 antibodies (AQP4) and anti-Myelin Oligodendrocyte Glycoprotein (MOG) have been able to classify NMO-SD into several groups. METHODS: A retrospective study was performed in the Strasbourg University Medical Center among patients with AQP4+, MOG+ and double-seronegative NMO to compare their clinical, epidemiological and paraclinical features. RESULTS: Thirty-two patients with NMO were included. The AQP4+ NMO patients had a median of age of 45 years, with associated myelitis in 62.5% of cases and other autoantibodies in 37.5% of cases. The mean number of relapses by clinical history was 3. The mean initial visual acuity during an exacerbation was 0.3 LogMAR, and the visual acuity after an exacerbation was 0.1 LogMAR. MOG+NMO patients had a median age of 23 years, with severely impaired initial visual acuity (0.6 LogMAR) but better recovery (0 LogMAR); optic disc edema was present in 80% of cases; the mean number of relapses on clinical history was 1. AQP4-/MOG- NMO's were more common in women (70%) and were bilateral in 40% of cases. CONCLUSION: The diagnostic characteristics of NMO-SD are becoming increasingly differentiated, with a positive impact on functional prognosis and long-term progression. Other biomarkers have yet to be identified to improve the diagnosis and treatment of these disorders.

[Myelitis as a differential diagnosis of spinal cord tumors]. / Diagnostic différentiel des tumeurs intramédullaires : les myélites.

BACKGROUND AND PURPOSE: Myelitis is common, related to multiple aetiologies and constitute in some cases a differential diagnosis for spinal cord tumors. Our objective was to review the clinical and paraclinical aspects of the main aetiologies of myelitis. METHODS: These aetiologies will be reviewed based on data not only from the scientific literature but also from our personal experience reported in different cohorts of patients. RESULTS: Multiple sclerosis is the main cause of partial myelitis in young adults. Neuromyelitis optica is now a well-known specific entity frequently revealed by a transverse myelitis. The diagnosis is based on specific criteria, including the presence of anti-NMO antibodies. In our cohorts, approximately 12 % of the patients admitted for an acute or subacute myelitis were related to infections, mainly of a viral origin. Patients with myelitis must be screened for systemic diseases. As for neuromyelitis optica, patients with myelitis related to a systemic disease should be treated in emergency. Acute myelitis is sometimes the first symptom of a systemic lupus or of a sarcoidosis. Sjögren syndrome can mimic myelitis related to primary progressive multiple sclerosis. Spinal cord imaging contributes greatly to defining the myelitis. CONCLUSION: In most cases, a routine clinical and paraclinical examination and the follow-up of the patients can contribute to establishing the aetiology of a myelitis.

[Nosology and etiologies of acute longitudinally extensive transverse myelitis]. / Cadre nosologique et stratégie diagnostique de la myélite aiguë transverse longitudinalement étendue.

Acute transverse myelitis had many names and definitions, based primarily on clinical criteria. The role of MRI in the exploration of myelitis has increased recently after the individualization of neuromyelitis optica (NMO) in 2004. This approach has enabled clarification of the diagnostic and prognostic value of acute longitudinally extensive transverse myelitis (LETM), defined by an extensive T2 lesion affecting three vertebral segments in the sagittal plane. The limitations of this definition, the multiplicity of terms used to characterize it as well as the large number of etiologies associated with it led our group of experts to clarify its etiology and nosology. We conducted a national survey on this subject in order to propose a new definition of LETM. Additional first- and second-intention examinations were determined according to the clinical context. Infectious/para-infectious, inflammatory or paraneoplastic causes can thus be identified. To determine within a short time the cause of LETM is essential, since most of its causes are severe and require urgent treatment.