The role of imaging in focal neuropathies.

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

Concurrent transverse myelitis and acute inflammatory demyelinating polyneuropathy.

A woman in her 40s presented with thoracic banding dysaesthesia and lower motor neuron weakness. Spinal imaging revealed a short segment of transverse myelitis and neurophysiology was suggestive of concurrent acute inflammatory demyelinating polyneuropathy. The patient improved with consecutive intravenous immunoglobulin and methylprednisolone treatment. Acute inflammatory demyelinating polyneuropathy is a progressive immune-mediated peripheral neuropathy which responds to intravenous immunoglobulin or plasmapheresis, whereas transverse myelitis is a central inflammatory syndrome usually treated with corticosteroid. We highlight differentiating features of the clinical presentation and the utility of investigations such as neurophysiology and MRI along with a review of treatment and the role for corticosteroid therapy.

Deficiency of adenosine deaminase 2: a genetic autoinflammatory disorder mimicking childhood polyarteritis nodosa.

A girl in the early adolescent age group presented with multisystem manifestations in the form of periodic fever, recurrent abdominal pain, hypertension, seizure, skin lesions over the chest and gangrene over the left ring and middle fingertips. Her condition had remained undiagnosed for 11 years. On evaluation, she had features of polyarteritis nodosa (PAN) (multiple aneurysms, symmetric sensorimotor peripheral neuropathy, superficial ulcers, digital necrosis, myalgia, hypertension and proteinuria). As childhood PAN is a phenocopy of adenosine deaminase 2 with a different management strategy, whole-exome sequencing was performed, which revealed a pathogenic variant in ADA2 gene. The child was treated with TNF alpha inhibitors and showed improvement in the Paediatric Vasculitis Activity Score. The paper highlights the gratifying consequences of correct diagnosis with disease-specific therapy that ended the diagnostic odyssey, providing relief to the patient from debilitating symptoms and to the family from the financial burden of continued out-of-pocket health expenditure.

Sweet syndrome with peripheral neuropathy in a patient with metastatic clear cell renal cell carcinoma.

A female patient in her 70s with a newly diagnosed clear cell renal cell carcinoma (ccRCC) with osseous metastasis presented with sudden onset erythematous painful blistering skin lesions on the dorsum of both hands, with associated intermittent fever episodes. Blood tests showed elevated inflammatory marker levels (C reactive protein 257.8 mg/dL, leucocytes 17.79×109/L, with 94% neutrophils). Histologically, there was predominately neutrophil dermal infiltrate without leucocytoclastic vasculitis. The diagnostic criteria of Sweet syndrome were fulfilled. A week later, the patient developed abrupt left-hand palsy, which was confirmed as a medial and ulnar sensorimotor axonal peripheral neuropathy of paraneoplastic origin. The patient was prescribed a course of oral high-dose steroids, which significantly improved the skin lesions. The peripheral nerve palsy improved after 3 months. This case describes the two very rare concurrent paraneoplastic manifestations of ccRCC occurring simultaneously, which have been rarely reported.

Severe papilloedema with vision loss secondary to Guillain-Barré syndrome.

We discuss a patient who presented with bilateral VI and VII cranial nerve palsies, symmetric upper and lower limb weakness and areflexia, 2 weeks following an flu-like illness. At presentation, there was no papilloedema, and her visual function was normal. Cerebrospinal fluid analysis and electrophysiology supported the diagnosis of Guillain-Barré Syndrome (GBS). She received intravenous immunoglobulins. She subsequently developed headaches and vision loss. Funduscopy demonstrated severe papilloedema with visual acuity of 6/18 right eye, 6/12 left eye with bitemporal visual field depression. Lumbar puncture revealed elevated opening pressure with high protein and normal cell count. She received acetazolamide. There was resolution of papilloedema and normal visual function at 3 months. Of note, the patient's body mass index was 17 kg/m2Our case highlights the rare occurrence of papilloedema in GBS, reiterating the importance of performing funduscopy on patients with any neurological diagnosis. Early detection and prompt management of papilloedema can prevent permanent vision loss.

Acute sensorimotor paraneoplastic neuropathy in a patient with small cell prostate cancer.

The authors describe a patient with a background of metastatic small cell prostate cancer who presented with a rapidly evolving sensorimotor neuropathy with bulbar features closely resembling Guillain-Barré syndrome, with a good initial response to intravenous immunoglobulins and platinum-based chemotherapy. This represented a likely paraneoplastic manifestation of the patient's urological malignancy.

Guillain-Barré syndrome following primary cytomegalovirus infection in a patient with liver transplantation.

We present the case of a man in his 60s with a 5-month medical history of deceased donor liver transplantation, who developed Guillain-Barré syndrome (GBS) secondary to a primary cytomegalovirus (CMV) infection. This was confirmed by molecular tests and serology antibodies that ruled out other frequent aetiologies. Therapy with intravenous immunoglobulin and valganciclovir was started and the patient gradually improved over the weeks. GBS is the most common aetiology of paralysis worldwide, and it is an autoimmune-mediated neuropathy that is frequently caused by a preceding infection. Few cases of GBS have been reported in the context of liver transplant recipients, and those related to CMV infection are extremely rare. This case highlights the importance of considering GBS as a possible differential diagnosis in patients with solid organ transplantation, and it contributes to the knowledge of other infrequent aetiologies of this condition.

Treatment-induced neuropathy of diabetes: challenges in diagnosing neuropathic pain, value of sudomotor function testing.

A patient in his 60s was admitted for an extensive neurological work-up due to progressive asymmetrical, distally pronounced pain in both feet and legs. Conventional pain relievers did not help in pain reduction. A Sudoscan revealed small fibre damage in all extremities indicating an underlying neuropathy. The patient had started insulin treatment around 6 months prior to hospitalisation because of a newly diagnosed late-onset diabetes. Due to a rapid drop in glycated haemoglobin (from over 14% to 6% in 4 months), treatment-induced neuropathy of diabetes (TIND) was hypothesised. On increasing the dose of pregabalin and adding duloxetine, the patient reported improvement of symptoms, which further underlined the suspected diagnosis. Hence, in patients with severe hyperglycaemia, changes in glycaemic control should be stepwise and not rapid; however, to date, no guidelines exist how to avoid TIND.

Epithelioid malignant peripheral nerve sheath tumour of the ulnar nerve around the elbow: a diagnostic and therapeutic challenge.

Epithelioid malignant peripheral nerve sheath tumour (EMPNST) is a rare histological subtype of malignant peripheral nerve sheath tumour (MPNST), accounting for 5% to 17% of MPNSTs. The clinical and MRI findings of EMPNST mimic those of nerve abscesses, similar to the presentation in Hansen's disease. We present one such case with this kind of diagnostic dilemma. Intraoperative findings suggest a tumour changed the course of management subsequently. The development of neurological deficits postoperatively after tumour resection was a reconstructive challenge. To provide motor power and sensation through a procedure that provides a complete functional outcome for a young patient, distal nerve transfers were chosen. This provided an improvement in the quality of life and hastened the neurological recovery of the involved limb. Level of evidence: V.

Parkes Weber syndrome: a rare cause of foot drop.

This case report describes a patient in her late 60s, previously diagnosed with Klippel-Trenaunay syndrome who presented with difficulty walking. A year prior to her presentation she had a fall which made her notice a painless foot drop on the right. Her right leg was profoundly hypertrophied compared with the left, and a port-wine stain was present on the lateral side, extending from the hip to the mid-shin. The patient's differential diagnosis based on clinical examination and investigations is discussed leading to a final diagnosis of sciatic neuropathy secondary to an arteriovenous malformation due to Parkes Weber syndrome.

Development of microscopic polyangiitis following idiopathic pleuroparenchymal l fibroelastosis: A case report.

Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a rare type of idiopathic interstitial pneumonia, which is characterised by pleural fibrosis and subjacent parenchymal fibroelastosis of the upper lobes. Herein, we present a case of microscopic polyangiitis (MPA) following PPFE. The patient had abnormal shadows on chest radiographs 15 years before the onset of MPA, and the patient was diagnosed with PPFE. Four years after the PPFE diagnosis, the patient was diagnosed with MPA based on persistent fever, purpura, mononeuritis multiplex, myeloperoxidase-antineutrophil cytoplasmic antibody positivity, and pathological findings of peritubular capillaritis on kidney biopsy. The patient was treated with glucocorticoids, including methylprednisolone pulse therapy and rituximab, followed by maintenance therapy with rituximab. One year after treatment, the PPFE had not worsened. PPFE occasionally occurs secondary to connective tissue disease, including MPA; however, to the best of our knowledge, this is the first report of PPFE preceding MPA. Our case suggests that PPFE, as other interstitial lung diseases, may be associated with MPA and precede the onset of MPA. The accumulation of more cases is needed to clarify the characteristics of MPA-associated PPFE.

Rare case of anti-CV2 paraneoplastic polyneuropathy associated with lung adenocarcinoma.

We describe the first case of anti-CV2 paraneoplastic polyneuropathy associated with lung adenocarcinoma. Our patient presented with progressive unsteadiness and numbness involving bilateral upper and lower limbs. He had symmetrical length-dependent lower motor neuron pattern of weakness and numbness involving both small and large fibres with prominent sensory ataxia. An extended workup for the polyneuropathy involving a serum paraneoplastic antineuronal antibody panel showed a positive reaction for anti-CV2 antibody. CT scan of the thorax, abdomen and pelvis revealed a right upper lung nodule and histopathological examination of the nodule revealed lung adenocarcinoma. He was scheduled for chemotherapy following his discharge and there was improvement of his sensorimotor polyneuropathy following his chemotherapy.

Myofibroma mimicking peripheral nerve sheath tumour with ulnar nerve compression symptoms.

We report a case of myofibroma encasing the ulnar nerve on the medial aspect of the left arm with motor and sensory deficit secondary to compression. Initially, the tumour appeared to be a benign peripheral nerve sheath tumour based on preoperative imaging, with clinical examination positive for left hand clawing and a positive Wartenberg's and Froment's sign. However, intraoperative dissection demonstrated that the mass did not originate from the ulnar nerve proper, lowering suspicion for a peripheral nerve sheath tumour. Histopathological analysis showed spindle cell neoplasm, consistent with myofibroma. The patient underwent hand occupational therapy subsequently, with improvement of grip strength from 5 lb to 12 lb by 4 months postoperatively and resolution of clawing of the hand postoperatively. We discuss differentiating features for this rare occurrence of solitary adult myofibroma, where the final diagnosis was only made after formal histopathological analysis.

Chronic inflammatory demyelinating polyneuropathy caused by hepatocellular carcinoma.

Paraneoplastic syndromes are rare abnormal endocrine or immune responses triggered by neoplasms. Chronic inflammatory demyelinating polyneuropathy (CIDP) is one such example. CIDP is an acquired, immune-mediated neuropathy affecting the peripheral nerves and nerve roots. It is associated with many types of cancers, especially haematological malignancies. We report the case of a man in his 60s who presented to the emergency department with acute symptoms of upper and lower extremity paresis and decreased sensation in the toes and tips of his fingers. Laboratory tests were normal. Electrodiagnostic studies showed diffuse motor and sensory dysfunction in all extremities; a diagnosis of CIDP was consequently made. Imaging studies showed a large left lobe liver mass. Subsequent biopsy revealed histopathological findings characteristic of hepatocellular carcinoma. After failure of medical treatment with intravenous immunoglobulin and corticosteroids, laparoscopic resection of the tumour was planned, performed and resulted in complete resolution of symptoms. At 18 months postoperatively, the patient was asymptomatic.

Knock-in mouse models for CMTX1 show a loss of function phenotype in the peripheral nervous system.

The X-linked form of Charcot-Marie-Tooth disease (CMTX1) is the second most common form of CMT. In this study we used CRISPR/Cas9 to develop new "knock-in" models of CMTX1 that are more representative of the spectrum of mutations seen with CMTX1 than the Cx32 knockout (KO) mouse model used previously. We compared mice of four genotypes - wild-type, Cx32KO, p.T55I, and p.R75W. Sciatic motor conduction velocity slowing was the most robust electrophysiologic indicator of neuropathy, showing reductions in the Cx32KO by 3 months and in the p.T55I and p.R75W mice by 6 months. At both 6 and 12 months, all three mutant genotypes showed reduced four limb and hind limb grip strength compared to WT mice. Performance on 6 and 12 mm width balance beams revealed deficits that were most pronounced at on the 6 mm balance beam at 6 months of age. There were pathological changes of myelinated axons in the femoral motor nerve in all three mutant lines by 3 months of age, and these became more pronounced at 6 and 12 months of age; sensory nerves (femoral sensory and the caudal nerve of the tail) appeared normal at all ages examined. Our results demonstrate that mice can be used to show the pathogenicity of human GJB1 mutations, and these new models for CMTX1 should facilitate the preclinical work for developing treatments for CMTX1.

Neurogenic orthostatic hypotension after treatment with sorafenib.

A man in his 70s with a history of fatigue, abdominal pain, and a palpable abdominal mass was found to have a peritoneal desmoid tumour. One year after diagnosis, he was prescribed sorafenib to limit tumour growth. Two months later, he developed dyspnoea on exertion and lower extremity weakness and was reported to have supine hypertension and orthostatic hypotension. On formal autonomic testing, he was noted to have severely impaired sympathetic responses and marked orthostatic hypotension without appropriate chronotropic response. A decision to hold sorafenib was made, and treatment was started with graduated compression stockings, liberal fluid and sodium intake, and midodrine. The patient had a modest and gradual improvement in his symptoms. To our knowledge, this is the first reported case of orthostatic hypotension related to sorafenib or any vascular endothelial growth factor inhibitors.

Pembrolizumab-induced acute right L5 neuritis unresponsive to steroids.

We present a case of a patient with metastatic lung adenocarcinoma who developed severe right lower limb radicular pain in a L5-S1 dermatomal distribution 5 months into treatment with carboplatin, pemetrexed and pembrolizumab. MRI of the lumbar spine demonstrated contrast enhancement of the right L5 nerve root consistent with neuritis. The patient was treated with intravenous methylprednisolone 2 mg/kg/day for 3 days, followed by oral prednisolone 1 mg/kg/day with a slow wean over 6 weeks. There was no improvement and their performance status deteriorated to an Eastern Cooperative Oncology Group (ECOG) score of 3, representing capability of only limited self-care. We commenced induction therapy with intravenous immunoglobulin 2 g/kg over 5 days, which resulted in complete resolution of pain sustained for 3 weeks before recurrence of symptoms. We continued maintenance therapy with intravenous immunoglobulin 0.4 g/kg over 2 days at 4-5 weekly intervals, which led to resolution of symptoms and ECOG score to 1.

Investigating the Effect of Zinc on the Prevention of Acute Peripheral Neuropathy in Cancer Patients Treated with Taxanes.

Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a major complication of many chemotherapeutic agents, including taxanes. Here, we aimed to investigate the effect of zinc on CIPN. Materials and Methods: This is a double-blinded controlled clinical trial that was performed in 2020-2021 in Isfahan on 55 cancer patients. We collected the data regarding CIPN, its severity, presence of abnormal deep-tendon reflexes, paresthesia, restriction in daily activities, and restriction in self-care and pain. Patients were divided into two groups: Patients in the first group were treated with capsules of zinc sulfate 25 mg daily and the control group received placebo. The duration of treatments was 3 months. Patients were visited 6, 9, and 12 weeks after study initiation. Results: There was a statistically significant decrease in the frequency of CIPN in the intervention group (37.03% vs. 14.8%, P < 0.001). The evaluation of the severity of neuropathy and presence of abnormal deep-tendon reflexes also demonstrated significant decrease in the intervention group during the study (P < 0.001 for both), but no significant changes were observed in the placebo group (P > 0.05). The activity limitations and pain severity improved significantly both in the intervention and placebo groups (P < 0.001 for both groups and items). The intervention group, however, had significantly lower frequencies of activity limitation and lower pain severity within compared to the control group during the study (P < 0.001). Conclusion: Zinc supplement therapy resulted in reduced frequency and intensity of CIPN in patients undergoing chemotherapy with taxanes.