The distribution of acquired peripheral nerve injuries associated with severe COVID-19 implicate a mechanism of entrapment neuropathy: a multicenter case series and clinical feasibility study of a wearable, wireless pressure sensor.

We diagnosed 66 peripheral nerve injuries in 34 patients who survived severe coronavirus disease 2019 (COVID-19). We combine this new data with published case series re-analyzed here (117 nerve injuries; 58 patients) to provide a comprehensive accounting of lesion sites. The most common are ulnar (25.1%), common fibular (15.8%), sciatic (13.1%), median (9.8%), brachial plexus (8.7%) and radial (8.2%) nerves at sites known to be vulnerable to mechanical loading. Protection of peripheral nerves should be prioritized in the care of COVID-19 patients. To this end, we report proof of concept data of the feasibility for a wearable, wireless pressure sensor to provide real time monitoring in the intensive care unit setting.

Differentiation between neurosarcoidosis and primary central nervous system vasculitis based on demographic, cerebrospinal and imaging features.

OBJECTIVES: Neurosarcoidosis (NS) and primary angiitis of central nervous system (PACNS) are inflammatory diseases affecting central nervous system, with overlapping clinical and pathological characteristics. Distinguishing these diseases is important given distinct therapeutic implications. In this study, we aimed to compare demographic, CSF and MRI characteristics between these two conditions. METHODS: All the clinical, CSF and laboratory characteristics at the time of presentation were retrieved from electronic medical records. Brain and/or spinal cord MRI performed near the time of presentation were blindly evaluated by two neuroradiologists. Data regarding involvement of pachy- and leptomeninges, basal meninges, cranial nerves, cerebral grey and white matter, and spinal cord were recorded for each patient. RESULTS: 78 patients with PACNS and 25 patients with NS were included in the study. Mean age of patients was 43.7 (±16.7) and 43.6 (±12.5) in PACNS and NS, respectively. African-American race was found to be associated with the diagnosis of NS rather than PACNS. Patients with PACNS had higher frequency of cerebral involvement, while patients with NS demonstrated more frequent spinal cord, basal meningeal and cranial nerve involvements. CONCLUSIONS: These findings suggest that MRI can be an efficient tool in distinguishing PACNS from NS. A follow-up study with a larger sample size would be required to validate our results.

Sural sensory nerve action potential, epidermal nerve fiber density, and quantitative sudomotor axon reflex in the healthy elderly.

INTRODUCTION: Polyneuropathy evaluation in older patients is often challenging due to conflicting data regarding normative values for peripheral nerve testing. METHODS: We characterized the results of sural nerve conduction studies, intraepidermal nerve fiber density (IENFD), and quantitative sudomotor axon reflex testing (QSART) in a prospective study of 50 healthy subjects aged ≥60 years. RESULTS: Of the 50 subjects, 48 (96%) had an obtainable sural sensory nerve action potential (SNAP). Using quantile regression, we estimated the lower limit of normal (LLN) for sural amplitudes to be 3 µV for patients 60-70 years, 1 µV for those 70-74 years, and <1 µV (absent) for those ≥75 years of age. IENFD and QSART volume were reduced with advancing age, although IENFD was lower in men and QSART volume was lower in women. CONCLUSIONS: We propose that an absent sural SNAP in patients up to 75 years of age should be considered abnormal. Our findings also support age- and gender-stratified normative data for IENFD and QSART.

Office approach to small fiber neuropathy.

Small fiber neuropathy is often characterized by neuropathic pain in the feet with normal nerve conduction studies and neurologic examination. Diagnosis requires specialized nerve tests, including autonomic studies and a skin biopsy study showing reduced intraepidermal nerve fiber density. Small fiber neuropathy has numerous causes but is often idiopathic. A practical approach to identifying an underlying cause is to first screen for common ones and then proceed with further testing as needed. Treatment consists of correcting the underlying cause, managing pain, and modifying lifestyle.

Immune Axonal Polyneuropathy.

PURPOSE OF REVIEW: Immune axonal polyneuropathy is caused by a diverse group of disorders that share similar presentations and treatment regimens. This article focuses on the clinical findings, evaluation, and management of immune-mediated causes of axonal polyneuropathy, focusing primarily on large fiber sensorimotor polyneuropathy. RECENT FINDINGS: Specific characteristics of an immune-mediated polyneuropathy have been incorporated in a new diagnostic screening tool that is highly sensitive and can easily be used in the outpatient clinic setting. New insights into autoantibodies may help identify the presence of an underlying autoimmune or paraneoplastic disease as the cause of a polyneuropathy. SUMMARY: This article provides readers with further understanding into the autoimmune causes of axonal polyneuropathy and will help the clinician recognize key clinical features that may lead to timely diagnosis and treatment.

Low Back Pain.

PURPOSE OF REVIEW: This article provides an overview of evaluating and treating low back pain in the outpatient setting. RECENT FINDINGS: As most cases of acute low back pain have a favorable prognosis, current guidelines on imaging studies recommend conservative treatment for 6 weeks prior to obtaining an MRI if no red flags are present. Of these red flags, a prior history of cancer is the strongest risk factor for a malignant etiology and requires urgent evaluation with MRI. Management of acute low back pain is mainly conservative with oral non-narcotic analgesics and mobilization as the initial recommendations. For patients with radiculopathy, epidural steroids may result in short-term pain relief, but long-term effects are still unclear. SUMMARY: A systematic, evidence-based approach to the patient with low back pain is key to providing safe and cost-efficient care.

Sarcoidosis-associated small fiber neuropathy in a large cohort: Clinical aspects and response to IVIG and anti-TNF alpha treatment.

OBJECTIVE: Small fiber neuropathy commonly affects patients with sarcoidosis and is often refractory to standard immunosuppressive therapies used for systemic disease. The clinical features of sarcoidosis-associated small fiber neuropathy (SSFN) and its response to medical therapy have not been described in a large population. METHODS: We performed a retrospective review of patients with SSFN seen at the Cleveland Clinic over a 4-year period. RESULTS: SSFN was identified in 143 individuals although other causes of neuropathy were found in 28 cases. Of the remaining 115 patients, 100 (87%) were Caucasian and 72 (63%) were female. Median age at reported neuropathy onset was 46 years (range 19-77 years), while median age of systemic diagnosis was 41 years. Pain and paresthesias were the most common symptoms, of which 54% were nonlength-dependent. Dysautonomia was seen in 61 patients with cardiac symptoms (orthostasis, palpitations) as the most common presentation followed by gastrointestinal and sweating dysfunction. Symptomatic improvement with treatment was seen in 47 of 62 patients that received IVIG, 8 of 12 patients that received anti-TNF and 10 of 14 patients who received combination therapy. Of 27 patients who were untreated, 4 improved. CONCLUSIONS: The most common presentation of SSFN in our series was a painful non-length dependent polyneuropathy with the highest overall incidence in Caucasian females. In most patients, neuropathy symptoms developed within 3 years of systemic sarcoidosis diagnosis. IVIG appeared beneficial in treating SSFN symptoms while nearly 2/3 of subjects also responded favorably to anti-TNF with or without IVIG. Further prospective studies are needed.

Smart device neuropathy.

Compression of the lateral femoral cutaneous nerve (LFCN) in the thigh, commonly referred to as meralgia paresthetica, may be due to obesity, tight clothing and other external factors. We report two cases of meralgia paresthetica due to compression of the LFCN by portable electronic or "smart" devices.

Neurosarcoidosis.

Neurosarcoidosis is known as the great mimicker and may appear similar to lymphoma, multiple sclerosis, and other diseases affecting the nervous system. Although definitive diagnosis requires histologic confirmation of the affected neural tissue, characteristic clinical manifestations, gadolinium-enhanced MRI patterns and specific cerebrospinal fluid findings can help support the diagnosis in the absence of neural biopsy. An understanding of the common clinical presentations and diagnostic findings is central to the evaluation and management of neurosarcoidosis.

Myelopathy due to degenerative and structural spine diseases.

PURPOSE OF REVIEW: This article reviews the current evaluation and treatment of patients with myelopathy due to cervical spondylotic disease and other structural disorders of the spine. RECENT FINDINGS: In patients with cervical spondylotic myelopathy, symptom duration, severity at baseline, and possibly age have been identified as key prognostic markers of clinical course and postsurgical outcome. Other potential markers include specific MRI and EMG findings. The diagnosis and monitoring of syringomyelia is enhanced by the addition of phase contrast MRI, which evaluates CSF flow dynamics. Flexion MRI is helpful in establishing the diagnosis of Hirayama disease, which is now attributed to a tightened dural sac that is displaced anteriorly on neck flexion, compressing the cord. SUMMARY: Advances in neuroimaging along with new insights into the pathophysiology of structural spine diseases can help guide clinical decision making and optimize patient outcomes.

Neurosarcoidosis.

PURPOSE OF REVIEW: This article provides an update on the evaluation and treatment of neurosarcoidosis. RECENT FINDINGS: The broad range of clinical manifestations of neurosarcoidosis has recently expanded to include painful small fiber neuropathy. Although definitive diagnosis remains a challenge, fluorodeoxyglucose positron emission tomographic (FDG-PET) scan and high-resolution CT allow for improved detection of systemic sarcoidosis. In addition, endobronchial ultrasound-guided transbronchial needle aspiration provides a less invasive means of tissue confirmation of systemic sarcoidosis than mediastinoscopy. Although not standardized, treatment strategies for neurosarcoidosis now commonly include tumor necrosis factor-α antagonists in combination with corticosteroids and other cytotoxic agents for patients with severe disease. SUMMARY: Advances in the diagnosis and management of neurosarcoidosis may benefit the patient and clinician faced with this multifaceted disease.

Efficacy of intravenous immunoglobulin for small fiber neuropathy associated with sarcoidosis.

BACKGROUND: Small fiber neuropathy (SFN) is commonly associated with sarcoidosis and can cause significant morbidity to afflicted patients. The appropriate treatment of this condition, when associated with sarcoidosis, is not well established. METHODS: Descriptive case series of three patients with sarcoidosis and SFN. The presenting clinical features, skin biopsy results, autonomic reflex screen and quantitative sudomotor axon reflex testing (QSART) findings, and response to therapy are delineated. RESULTS: We describe three patients with biopsy-proven sarcoidosis who developed intractable neuropathic pain and/or symptoms related to associated autonomic dysfunction despite treatment with various immunosuppressive medications and narcotic analgesics. QSART showed evidence of a postganglionic sudomotor abnormality in one patient and was normal in the other two. Skin biopsy findings were abnormal, demonstrating a non-length-dependent sensory SFN in all three patients. Painful neuropathic symptoms, as well as symptoms related to dysautonomia from SFN responded significantly to treatment with intravenous immunoglobulin (IVIG). CONCLUSION: IVIG appears to be effective in relieving symptoms from SFN associated with sarcoidosis, suggesting an underlying immune mechanism. Larger prospective, controlled studies would be needed to confirm this response to IVIG and to further elucidate the underlying pathobiology behind this association with sarcoidosis.

Response to intravenous immunoglobulin in anti-Yo associated paraneoplastic cerebellar degeneration: case report and review of the literature.

Paraneoplastic cerebellar degeneration (PCD) is a debilitating neuro-degenerative disease associated with antibodies directed against the purkinje cells of the cerebellum. Treatment using chemotherapy or other treatment of the primary tumor to various immunologically directed therapies has been attempted but outcomes have been poor. We discuss a patient with ovarian carcinoma and PCD seen in our institution who showed a marked beneficial response to intravenous immunoglobulin (IVIG) and methylprednisolone. A Medline search from 1966-2002 produced fifteen cases of PCD confirmed by antibody testing that were treated with IVIG, either alone, or with a combination of other therapies. The clinical characteristics and treatment responses of these patients are analyzed in this review. Most patients that were treated with IVIG and had what was defined as a good response were treated within one month of symptoms. Patients treated between one month and three months often had stable disease and patients treated after three months of symptoms usually had a poor outcome. Early treatment with sufficiently high doses of IVIG seems to provide a better chance of treatment success. The additional benefit of early high dose intravenous methylprednisolone is unclear. Due to the devastating nature of the disease, a trial of IVIG and steroids is warranted as early as possible in a dose of 2g/kg to any patient with a clinical picture of PCD and positive antibodies.