Frequency of EMG abnormalities in idiopathic inflammatory myopathies under the EULAR/ACR classification criteria.

The European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for idiopathic inflammatory myopathies (IIM) have been widely used in recent times. However, no studies have focused on electromyography (EMG) findings of IIM, considering the criteria. This study aimed to elucidate the frequency of EMG abnormalities, particularly fibrillation potentials and positive sharp waves (Fib/PSW), the most objective EMG findings of IIM. Clinical and EMG records of adult patients who were clinically diagnosed with polymyositis (PM), dermatomyositis (DM), amyopathic DM (ADM), or inclusion body myositis (IBM) were retrospectively reviewed and classified according to the EULAR/ACR classification criteria. The frequency of Fib/PSW in EMG was investigated in the recruited cases. Seventy-nine patients with clinically diagnosed IIM (44 with PM, 17 with DM, 7 with ADM, and 11 with IBM) were recruited. After classification using EULAR/ACR, 75 satisfied definite or probable IIM (61 and 14, respectively), and the frequency of Fib/PSW in this group was 95%. Furthermore, the remaining 4 patients with insufficient IIM probability also showed Fib/PSW. Fib/PSW may also be seen in cases with insufficient IIM probability not satisfying the criteria. EMG may help detect muscle involvement in these cases through Fib/PSW.

Different Tendencies in Muscle Ultrasound Characteristic in Amyotrophic Lateral Sclerosis and Chronic Inflammatory Demyelinating Polyradiculoneuropathy.

INTRODUCTION: The difference in muscle ultrasound (MUS) characteristics in primary axonal degeneration and demyelination has not been well established. The authors aimed to investigate the subject based on the correlation between MUS findings (echo intensity and muscle thickness) and compound muscle action potential (CMAP) amplitude in amyotrophic lateral sclerosis (ALS) and chronic inflammatory demyelinating polyradiculoneuropathy. METHODS: Fifteen patients with ALS and 16 patients with chronic inflammatory demyelinating polyradiculoneuropathy were examined. For each patient, echo intensity and muscle thickness of the abductor pollicis brevis, abductor digiti minimi, and first dorsal interosseous muscles were investigated. Compound muscle action potential amplitudes were measured by median and ulnar nerve conduction studies. RESULTS: In total, 45 muscles were evaluated in each group. The ALS group showed a linear correlation between the MUS finding and CMAP amplitude (rs = -0.70 and 0.59 for echo intensity and muscle thickness, respectively), whereas the chronic inflammatory demyelinating polyradiculoneuropathy group showed a weaker correlation than the ALS group (rs = -0.32 for echo intensity and rs = 0.34 for muscle thickness). CONCLUSIONS: The relationship between MUS abnormalities and CMAP amplitude showed different tendencies in ALS and chronic inflammatory demyelinating polyradiculoneuropathy. The results suggested that MUS abnormalities substantially reflect the muscle function in primary axonal degeneration, whereas a discrepancy between MUS findings and muscle function can be frequently seen in demyelination; specifically, MUS findings tend to be normal even though CMAP showed a reduction. These tendencies originating from underlying pathophysiology should be considered when MUS findings are used as biomarkers of disease severity.

Utility of nerve ultrasound in the management of primary neurolymphomatosis: Case report and review of the literature.

Introduction: Primary neurolymphomatosis (NL) is a critical differential diagnosis of asymmetric multiple mononeuropathy and radiculoplexopathy. Its diagnosis is often challenging due to the lack of typical clinical signs of systemic lymphoma. We report a case of primary NL where nerve ultrasound (NUS) played an important role in the diagnosis and follow-up of the disease. Case presentation: A 52-year-old man developed asymmetric painful multiple mononeuropathy in the right upper limb with cranial nerve involvement. After being referred to our department, the patient underwent NUS, which revealed marked enlargement and increased vascularity in the right upper limb nerves, brachial plexus, and cervical nerve roots. Furthermore, an epineural hypoechoic mass, a characteristic finding of NL, was seen in the right median nerve. These NUS findings prompted us to perform 18F-fluorodeoxyglucose positron emission tomography/computed tomography and a subsequent biopsy on the right axillary lymph node, confirming NL. Notably, the NUS abnormalities dramatically subsided, demonstrating the effectiveness of chemotherapy. Discussion: The diagnostic utility of NUS for NL has been documented by many recent reports. Additionally, NUS can work as a quick follow-up tool for NL, as seen in our case.

Nasogastric Tube Syndrome: The Size and Type of the Nasogastric Tube May Contribute to the Development of Nasogastric Tube Syndrome.

Nasogastric tube syndrome (NGTS) is a rare but life-threatening complication associated with nasogastric tube (NGT) placement. The effect of the NGT size and type on the development of NGTS has not yet been fully elucidated. We herein report the case of a 77-year-old man with cerebral infarction who was complicated with NGTS. The immediate removal of the NGT improved the symptoms of NGTS. Although the NGT was passed through the same route during reinsertion, the use of a softer and smaller-sized NGT did not cause any NGTS recurrence. To prevent the development of NGTS, using a NGT that is appropriate for the patient's condition is important.

[Primary central nervous system methotrexate associated lymphoproliferative disorders in a patient with rheumatoid arthritis].

We report on a 52-year-old woman with rheumatoid arthritis (RA) who developed methotrexate associated lymphoproliferative disorders (MTX-LPD) in the central nervous system (CNS) in the course of immunosuppressive therapy for RA. The patient was admitted because of monoplegia in her left hand. She had been receiving methotrexate (MTX) for her RA for several years and etanercept had also been introduced because of a worsening of the arthritis six months before admission. Brain MRI revealed multiple lesions with enhancement scattered throughout both hemispheres. 18F-fluorodeoxyglucose-positron emission tomography/computed tomography showed abnormal accumulation suggesting malignancy in the right frontal lobe where abnormal enhancement was observed on the MRI. A brain biopsy was performed at the identified site and it confirmed diffuse large B-cell lymphoma (DLBCL). We therefore diagnosed her as MTX-LPD. According to previous reports, most MTX-LPD cases tend to show regression after the cessation of MTX. However, our case showed no regression and even needed chemotherapy. The patient had a poorer prognosis than previous cases and died 17 months after the onset. Although it is an uncommon complication, particularly in the CNS, MTX-LPD should be considered as a critical differential diagnosis if a patient receiving MTX develops central nervous system lesions. Immediate medical intervention including brain biopsy is required.

[Right parietal cerebral infarction with symptoms challenging to differentiate between alien hand sign and sensory ataxia: a case report].

We report the case of a 73-year-old right-handed female with a right parietal cerebral infarction and presented symptoms that were challenging to differentiate between alien hand sign (AHS) and sensory ataxia. She presented to our emergency department with chief complaints of abnormal involuntary movements and a feeling of foreignness on her left upper limb. The first neurological examination revealed left spatial neglect, left-side sensory impairment that included superficial and deep sensations, left limb-kinetic apraxia, and left limb ataxia. Furthermore, her symptoms and complaints had characteristics of AHS that includes a sensation that her left upper limb dose not belong to herself and an abnormal behavior of left hand that is contrary to her own intent. Brain MRI revealed an acute cerebral infarction confined to the right postcentral gyrus. This case highlights that sensory ataxia due to the disturbance of deep sensation might present symptoms similar to AHS. Previous studies suggested the involvement of the disturbance of somatosensory pathway in posterior-variant AHS. Therefore, a precise distinction between AHS and sensory ataxia, especially in posterior-variant AHS, is imperative to avoid confusion regarding the term "alien hand sign."

Quantitative muscle ultrasound is useful for evaluating secondary axonal degeneration in chronic inflammatory demyelinating polyneuropathy.

INTRODUCTION: In chronic inflammatory demyelinating polyneuropathy (CIDP), exclusion of secondary axonal degeneration is challenging with conventional methods such as nerve conduction study (NCS), needle electromyography, and nerve biopsy. Increased echo intensity (EI) and decreased muscle thickness (MT) identified on muscle ultrasound (MUS) examination represent muscle denervation due to axonal degeneration in neurogenic disorders, suggesting MUS as a new tool to detect secondary axonal degeneration in patients with CIDP. METHODS: EI and MT of abductor pollicis brevis, abductor digiti minimi, and first dorsal interosseous muscles were measured in 16 CIDP patients. Raw values were converted into z-scores using data from 60 normal controls (NCs). RESULTS: Six of 45 muscles showed abnormally high EI and low MT, suggesting denervation following secondary axonal degeneration. These six muscles belonged to two patients with long disease history, unresponsiveness to treatment, and long interval from onset to initial therapy. There were no significant differences in EI and MT (p = .23 and .67, respectively) between the CIDP and NC groups, although NCS results revealed obvious demyelinating abnormalities in all CIDP patients, suggesting the fact that muscle structures will be preserved, and EI and MT will not change unless secondary axonal degeneration occurs in CIDP. CONCLUSION: MUS is a promising tool for evaluating secondary axonal degeneration in patients with CIDP.