Neuralgic amyotrophy and COVID-19 infection: 2 cases of spinal accessory nerve palsy.

OBJECTIVE: Neuralgic amyotrophy (NA), also known as Parsonage-Turner syndrome is often triggered by mechanical stress or viral infections. We reported 2 cases of shoulder weakness and amyotrophy related to spinal accessory nerve (SAN) palsy due to neuralgic amyotrophy occurring after COVID-19 infection. METHODS: For both patients, clinical history, clinical examination, electrodiagnostic (EDX), and imaging examinations invalidated other diagnoses but confirmed NA diagnosis. RESULTS: The NA involved only the SAN in both cases. EDX revealed a characteristic axonal lesion found in NA. SAN conduction study revealed normal latencies and low compound motor action potential amplitude for trapezius muscle when needle examination demonstrated a neurogenic pattern and denervation signs in the trapezius muscle. Both patient's MRI revealed denervation T2 hyper signal in impaired muscles, without any mass, cyst, injury, fibrous band, or tearing signs along SAN course. CONCLUSIONS: The COVID-19 infection could be the trigger for NA as many other viruses, and as it is a possible trigger for Guillain-Barré syndrome.

Small fiber neuropathy in Sjögren syndrome: Comparison with other small fiber neuropathies.

INTRODUCTION: We compared histological and clinical profiles of primary Sjögren syndrome (pSS) small fiber neuropathy (SFN; pSS-SFN) with idiopathic SFN (i-SFN) and hereditary transthyretin amyloidosis SFN (hATTR-SFN) and described the evolution of pSS-SFN. METHODS: All patients with pSS-SFN, i-SFN, and hATTR-SFN confirmed by reduced intraepidermal nerve fiber density on skin biopsy were retrospectively included, and their characteristics were compared. To analyze prognosis of pSS-SFN, patients prospectively underwent a second evaluation. RESULTS: Fifteen pSS-SFN, 17 hATTR-SFN, and 11 i-SFN were included. Time to diagnosis SFN was longer in pSS-SFN and i-SFN than in hATTR-SFN. Painful and non-length-dependent patterns were more frequent in pSS-SFN than in hATTR-SFN. Twelve (80%) patients with pSS-SFN had a non-length-dependent pattern. Ten patients with pSS were reassessed after 3.1 years (1.7-4.7); none developed large fiber neuropathy linked to pSS. DISCUSSION: Primary Sjögren syndrome SFN is characterized by a more frequent non-length-dependent pattern compared with i-SFN and hATTR-SFN. Primary Sjögren syndrome SFN did not evolve through large fiber neuropathy.

Contribution of plexus MRI in the diagnosis of atypical chronic inflammatory demyelinating polyneuropathies.

Nerve enlargement has early been recognized in CIDP and plexus MRI hypertrophy has been reported in typical CIDP cases. Our aim is to determine plexus MRI value in the diagnosis of CIDP with an initial atypical presentation, which, up to now, has not been demonstrated. Retrospective study of 33 consecutive patients suspected of CIDP. Plexus MRI was performed on the most affected territory (brachial or lumbar). Were assessed: plexus trophicity, T2-STIR signal intensity and gadolinium enhancement. Final CIDP diagnosis was made after comprehensive workup. A histo-radiological correlation was performed. Final CIDP diagnosis was made in 25 (76%) including 21 with initial atypical clinical presentation. Eleven CIDP patients (52%) with initial atypical clinical presentation had abnormal plexus MRI including 9 suggestive of CIDP (43%) and none of the patients with an alternative diagnosis. Hypertrophy of the proximal plexus and/or extraforaminal roots was found in 8 cases and Gadolinium enhancement in 2 cases. Abnormalities were more frequent on brachial (86%) than lumbosacral MRIs (29%) and asymmetrical (72%) and most often associated with histological signs of demyelination. The nerve biopsy was suggestive of CIDP in 9/13 patients with normal MRI. Plexus MRI seems useful in the diagnostic strategy of patients with suspicion of CIDP with atypical presentation. Nerve biopsy remains important when other investigations are inconclusive.

Statistical analysis of multi-b factor diffusion weighted images can help distinguish between vasogenic and tumor-infiltrated edema.

PURPOSE: The diffusion model can be transformed into a multicompartment model by means of multi-b factor diffusion-weighted sequences. We adapted a method of statistical analysis of these images and evaluated its performance to distinguish tumor-infiltrated edema from vasogenic edema. MATERIALS AND METHODS: Forty-nine patients with infiltrating tumors (38 patients: low to high-grade gliomas) or vasogenic edema (11 patients: metastases, abscess, extra-axial lesions) were studied by multi-b factor diffusion-weighted imaging. Comparison of histological results and morphological and perfusion MRI defined 69 characteristic volumes of interest in the peritumoral edema of 69 distinct infiltrating lesions (40) or lesions inducing vasogenic edema (29). RESULTS: The factorial analysis had a sensitivity of 92.9% and a specificity of 90.6% between tumor-infiltrated and vasogenic edema. Simplified interpretation confined to values of the high and mean diffusivity compartments had a sensitivity of 87.5% and a specificity of 89.2% between strictly tumor-infiltrated edema and vasogenic edema with the advantage of simplified interpretation based on two-color parametric mapping. CONCLUSION: Discrimination between tumor-infiltrated edema and vasogenic edema can be achieved by means of a 90-s multi-b factor diffusion-weighted sequence and factorial analysis. Simplified visual and quantitative interpretation of the results should also allow integration of multi-b factor analysis into routine neuroradiology practice.

Auricular chondritis and thrombotic microangiopathy: an unusual combination revealing systemic lupus erythematosus.

Thrombotic microangiopathy is a severe disorder, which is a cause of stroke in young patients. Etiologic investigations are mandatory to diagnose underlying disease. Systemic lupus erythematosus is one of the diseases, which can be associated with thrombotic microangiopathy. Although lupus diagnosis is usually easy, relying on characteristic clinical manifestations, rare symptoms can be misinterpreted. We report here a case of polychondritis, which was the first manifestation of a lupus-associated thrombotic microangiopathy.