Vasculitic Neuropathies

Burden, Outcome, and Comorbidities of Extrahepatic Manifestations in Hepatitis B Virus Infections

Hepatitis B virus (HBV) infections affect approximately 296 million people around the world, and the prevalence of any past or present HBV infection during the years 2015-2018 was as high as 4.3%. Acute HBV infection often presents with nonspecific symptoms and is usually self-limited, but 5% of patients can have persistent infections leading to chronic HBV infection and the risk of turning into chronic HBV infection is significantly higher in babies with vertical transmission (95%). Patients with chronic HBV infection are usually asymptomatic, but 15 to 40% of chronic HBV carriers develop cirrhosis and/or hepatocellular carcinoma. In addition to liver-related disorders, HBV is also associated with several extrahepatic complications, including glomerulonephritis, cryoglobulinemia, neurologic disorders, psychological manifestations, polyarthritis, and dermatologic disorders. Making the diagnosis of HBV can be challenging since patients with chronic infections can remain symptom-free for decades before developing cirrhosis or hepatocellular carcinoma, and patients with acute HBV infection may have only mild, nonspecific symptoms. Therefore, understanding how this virus causes extrahepatic complications can help clinicians consider this possibility in patients with diverse symptom presentations. The pathophysiology of these extrahepatic disorders likely involves immune-related tissue injury following immune complex formation and inflammatory cascades. In some cases, direct viral infection of extrahepatic tissue may cause a clinical syndrome. Currently, the American Association for the Study of Liver Diseases recommends treatment of chronic HBV infections with interferon therapy and/or nucleos(t)ide analogs, and this treatment has been reported to improve some extrahepatic disorders in some patients with chronic HBV infection. These extrahepatic complications have a significant role in disease outcomes and increase medical costs, morbidity, and mortality. Therefore, understanding the frequency and pathogenesis of these extrahepatic complications provides important information for both specialists and nonspecialists and may help clinicians identify patients at an earlier stage of their infection.

Focal inflammatory neuropathies

This chapter focuses on neuropathies that present with focal involvement of nerve roots, plexus, and/or peripheral nerves associated with autoimmune and inflammatory mechanisms that present with focal involvement of nerve roots, plexus and/or peripheral nerves. The clinical presentation, diagnosis, and treatment of focal autoimmune demyelinating neuropathies, focal nonsystemic vasculitic disorders (diabetic and nondiabetic radiculoplexus neuropathies, postsurgical inflammatory neuropathy, and neuralgic amyotrophy), and focal neuropathies associated with sarcoidosis and bacterial and viral infections are reviewed.

Central and Peripheral Nervous System Complications of Vasculitis Syndromes from Pathology to Bedside: Part 2-Peripheral Nervous System

PURPOSE OF REVIEW

Peripheral nervous system vasculitides (PNSV) are a heterogeneous group of disorders with a clinical subset that may differ in prognosis and therapy. We provide a comprehensive update on the clinical assessment, diagnosis, complications, treatment, and follow-up of PNSV.

RECENT FINDINGS

Progress in neuroimaging, molecular testing, and peripheral nerve biopsy has improved clinical assessment and decision-making of PNSV, also providing novel insights on how to prevent misdiagnosis and increase diagnostic certainty. Advances in imaging techniques, allowing to clearly display the vessel walls, have also enhanced the possibility to differentiate inflammatory from non-inflammatory vascular lesions, while recent histopathology data have identified the main morphological criteria for more accurate diagnosis and differential diagnoses. Overall, the identification of peculiar morphological findings tends to improve diagnostic accuracy by defining a clearer boundary between systemic and non-systemic neuropathies. Therefore, the definition of epineurium vessel wall damage, type of vascular lesion, characterization of lymphocyte populations, antibodies, and inflammatory factors, as well as the identification of direct nerve damage or degeneration, are the common goals for pathologists and clinicians, who will both benefit for data integration and findings translation. Nevertheless, to date, treatment is still largely empiric and, in some cases, unsatisfactory, thus often precluding precise prognostic prediction. In this context, new diagnostic techniques and multidisciplinary management will be essential in the proper diagnosis and prompt management of PNSV, as highlighted in the present review. Thirty to fifty percent of all patients with vasculitis have signs of polyneuropathy. Neuropathies associated with systemic vasculitis are best managed according to the guidelines of the underlying disease because appropriate workup and initiation of treatment can reduce morbidity. Steroids, or in severe or progressive cases, cyclophosphamide pulse therapy is the standard therapy in non-systemic vasculitic neuropathies. Some patients need long-term immunosuppression. The use of novel technologies for high-throughput genotyping will permit to determine the genetic influence of related phenotypes in patients with PNSV.

Autoimmune polyneuropathies

The autoimmune peripheral neuropathies with prominent motor manifestations are a diverse collection of unusual peripheral neuropathies that are appreciated in vast clinical settings. This chapter highlights the most common immune-mediated, motor predominant neuropathies excluding acute, and chronic inflammatory demyelinating polyradiculoneuropathy (AIDP and CIDP, respectively). Other acquired demyelinating neuropathies such as distal CIDP and multifocal motor neuropathy will be covered. Additionally, the radiculoplexus neuropathies, resulting from microvasculitis-induced injury to nerve roots, plexuses, and nerves, including diabetic and nondiabetic lumbosacral radiculoplexus neuropathy and neuralgic amyotrophy (i.e., Parsonage-Turner syndrome), will be included. Finally, the motor predominant peripheral neuropathies encountered in association with rheumatological disease, particularly Sjögren's syndrome and rheumatoid arthritis, are covered. Early recognition of these distinct motor predominant autoimmune neuropathies and initiation of immunomodulatory and immunosuppressant treatment likely result in improved outcomes.

Chronic Immune-Mediated Polyneuropathies

This article discusses the chronic immune-mediated polyneuropathies, a broad category of acquired polyneuropathies that encompasses chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), the most common immune-mediated neuropathy, the CIDP variants, and the vasculitic neuropathies. Polyneuropathies associated with rheumatological diseases and systemic inflammatory diseases, such as sarcoidosis, will also be briefly covered. These patients' history, examination, serum studies, and electrodiagnostic studies, as well as histopathological findings in the case of vasculitis, confirm the diagnosis and differentiate them from the more common length-dependent polyneuropathies. Prompt identification and initiation of treatment is imperative for these chronic immune-mediated polyneuropathies to prevent disability and even death.

Nerve biopsy findings contribute to diagnosis of multiple mononeuropathy: 78% of findings support clinical diagnosis

Multiple mononeuropathy is an unusual form of peripheral neuropathy involving two or more nerve trunks. It is a syndrome with many different causes. We reviewed the clinical, electrophysiological and nerve biopsy findings of 14 patients who suffered from multiple mononeuropathy in our clinic between January 2009 and June 2013. Patients were diagnosed with vasculitic neuropathy (n = 6), perineuritis (n = 2), chronic inflammatory demyelinating polyradiculoneuropathy (n = 2) or Lewis-Sumner syndrome (n = 1) on the basis of clinical features, laboratory data, electrophysiological investigations and nerve biopsies. Two patients who were clinically diagnosed with vasculitic neuropathy and one patient who was clinically diagnosed with chronic inflammatory demyelinating polyradiculoneuropathy were not confirmed by nerve biopsy. Nerve biopsies confirmed clinical diagnosis in 78.6% of the patients (11/14). Nerve biopsy pathological diagnosis is crucial to the etiological diagnosis of multiple mononeuropathy.

Vasculitic neuropathies

The vasculitic neuropathies are a diverse group of disorders characterised by the acute-to-subacute onset of painful sensory and motor deficits that result from inflammatory destruction of nerve blood vessels and subsequent ischaemic injury. They are common in patients with primary systemic vasculitis and are seen in vasculitis secondary to disorders such as rheumatoid arthritis, viral infections, and diabetic inflammatory neuropathies. It is imperative that neurologists recognise these disorders to initiate treatment promptly and thereby prevent morbidity and mortality. To simplify the approach to patients with vasculitis of the peripheral nerves, a straightforward, dichotomous classification scheme can be used in which the vasculitic neuropathies are divided into two groups-nerve large arteriole vasculitis and nerve microvasculitis-on the basis of the size of the involved vessels. The size of the affected blood vessels correlates with the clinical course and prognosis in patients with vasculitic neuropathy.

Peripheral neuropathy: clinical and electrophysiological considerations

This article is a primer on the pathophysiology and clinical evaluation of peripheral neuropathy for the radiologist. Magnetic resonance neurography has utility in the diagnosis of many focal peripheral nerve lesions. When combined with history, examination, electrophysiology, and laboratory data, future advancements in high-field magnetic resonance neurography may play an increasingly important role in the evaluation of patients with peripheral neuropathy.

Intravenous immunoglobulin therapy in vasculitic ulcers: a case of polyarteritis nodosa

Introduction

Polyarteritis nodosa (PAN) is a systemic necrotizing medium-size-vessel vasculitis with variable clinical manifestations. Diagnosis is confirmed by histology or angiography. The mainstay of treatment is corticosteroids alone or combined with cyclophosphamide (CYF).

Case report

Seventy-one-year-old female, follow-up started in 1997 at the age of 56 for suspected relapsing febrile viral exanthema. Skin biopsy was performed and the diagnosis of lymphomatoid papulosis was made, with complete response to treatment with dapsone. In 2005, she presented with arthralgia, lower limb (LL) edema, livedo reticularis and elevated erythrocyte sedimentation rate (ESR). PAN was confirmed on histology and visceral angiography; antineutrophil cytoplasmic antibodies (ANCA) were negative. She responded to prednisolone but relapsed in 2006. Twelve cycles of CYF were administered, with clinical, angiographic and analytical improvement. In 2008, a new relapse occured with LL neuropathic pain and ESR elevation. Electromyogram (EMG) confirmed axonal sensory polyneuropathy (PNP). Azathioprine was started with a poor response. A second EMG, 12 months later in 2009 still evidenced PNP, and nerve biopsy confirmed vasculitic neuropathy. In 2010, she had ulcers in LL and iron-deficient anemia. She started intravenous immunoglobulin (IVIG) for six cycles, achieving ulcer healing, absence of pain, no anemia and ESR normalization.

Discussion

IVIG therapy has proven benefit in Kawasaki disease, also showing efficacy in refractory ANCA-associated vasculitis. In PAN, only very few case reports show benefit. In this case, IVIG therapy induced total remission of LL ulcers and PNP, suggesting that it may be useful in selected cases of refractory PAN.

Usefulness of superficial peroneal nerve/peroneus brevis muscle biopsy in the diagnosis of vasculitic neuropathy

Sensitivity, specificity, and diagnostic yield of the superficial peroneal nerve (SPN)/peroneus brevis muscle (PBM) biopsy in 43 patients with clinically suspected vasculitic neuropathy was studied. Biopsies were classified as "definite", "suspicious" or "possible" in accordance with established criteria. Vasculitis was detected in 27 patients (21 with non-systemic vasculitis, and six with systemic vasculitis). In patients with "definite" vasculitis (n=13), the sensitivity of SPN/PBM biopsy was 76.4% with 100% specificity. By including patients suspicious for vasculitis (n=10), sensitivity increased to 85.1% but the specificity dropped to 87.5%. The overall diagnostic yield of SPN biopsy in those patients with definite vasculitis was 76.9% (10/13), and 53.8% (7/13) for muscle biopsy. The addition of muscle biopsy increased the diagnostic yield by 23%. Asymmetric nerve fiber loss, Wallerian degeneration and presence of hemosiderin were statistically significant markers of probable vasculitis. Muscle tissue was more likely to show hemosiderin (85.7%) than a nerve biopsy (71%). A combined SPN/PBM biopsy offers excellent diagnostic yield in the diagnosis of vasculitic neuropathy.

Treatment in inflammatory neuropathies

This review focuses on recent developments in the treatment of inflammatory neuropathies arising from immune dysregulation, rather than from infectious causes. The dysimmune inflammatory neuropathies are diseases of the peripheral nerves that have varying etiologies and may respond to immunomodulatory therapies. They are characterized by inflammatory changes in the nerve with associated destruction of myelin and axons. The underlying immune mechanisms are better understood in some of these conditions than others. Correct diagnosis and treatment is important to prevent clinical progression. Randomized controlled trials of some treatments in the more common inflammatory neuropathies have clarified their effectiveness; however, there are still groups of patients who are resistant to currently available treatments and for whom little effective treatment is available. Newer, targeted biologics and larger controlled trials of existing and novel therapies in these conditions offer promise of improved morbidity and mortality in this group of diseases.

Commentary: "Who was caring for Mary?" revisited: a call for all academic physicians caring for patients to focus on systems and quality improvement

Over 15 years have passed since Mary's near death (Annals of Internal Medicine. 1993;118:146-148). Disappointment in the care by fellow academic physicians persists; however, a reanalysis of her case through the lens of complex systems design and performance yields a more accurate and actionable perspective. Mary's suffering was not due to human failure alone. Human failure was provoked and exacerbated by broken processes including ambiguous assignments of responsibility; inadequate transfers of information and authority; unreliable or unavailable protocols for providing safe, effective treatment; and a failure to integrate the deep but narrow perspectives of individual specialists into a complete picture of Mary's condition. Her case exemplifies, in personal terms, many of the system challenges academic medical centers face: Faculty have other missions that can conflict with patient care; disease complexity is high, requiring input from multiple subspecialists; clinical departments serve as roadblocks to communication; and novice physicians, requiring close supervision, have primary responsibility for the day-to-day care of acutely ill patients. The academic physicians who first cared for Mary unwittingly accepted flawed systems, and they failed to work around them. At great monetary and emotional expense, last-minute heroics saved Mary. In a dysfunctional system, even the most conscientious physician may be viewed as uncaring. As Mary's case so clearly illustrates, patients and their families see the system and the physician as one. Only by working to improve the systems of delivery will academic physicians again be consistently viewed as caring.

Molecularly targeted therapies for dysimmune neuropathies

Conventional treatment options, including corticosteroids, intravenous immunoglobulin, or plasma exchange, often fail to treat dysimmune neuropathies, such as chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and monoclonal gammopathy with its subtypes. Therefore, a significant percentage of patients require adjunctive immunosuppressive therapies. Considering that even immunosuppressive agents often are ineffective and/or associated with significant toxicities, the need for the development of safe and effective new treatment options is rising. Currently, several monoclonal antibodies (MAbs) have been tested in open-label small-sized studies or even in single cases so as to establish future directions in the therapy of diseases of the peripheral nervous system (PNS). Rituximab, an MAb targeting against the B cell surface membrane protein CD20, is the most widely used and promising MAb for the treatment of dysimmune neuropathies, especially for those in which immunoglobulin M (IgM) autoantibodies are pathogenetically involved. The efficacy of alemtuzumab, bevacizumab, and etanercept to treat various forms of dysimmune neuropathies is currently under investigation. This review looks critically at recent developments in molecularly targeted therapies for dysimmune neuropathies and also highlights areas of future research to pursue.

Diagnosis and treatment in inflammatory neuropathies

The inflammatory neuropathies are a large diverse group of immune-mediated neuropathies that are amenable to treatment and may be reversible. Their accurate diagnosis is essential for informing the patient of the likely course and prognosis of the disease, informing the treating physician of the appropriate therapy and informing the scientific community of the results of well-targeted, designed and performed clinical trials. With the advent of biological therapies able to manipulate the immune response more specifically, an understanding of the pathogenesis of these conditions is increasingly important. This review presents a broad overview of the pathogenesis, diagnosis and therapy of inflammatory neuropathies, concentrating on the most commonly encountered conditions.

Neuroleukemiosis: case report of leukemic nerve infiltration in acute lymphoblastic leukemia

We describe a patient in remission from acute lymphoblastic leukemia who developed a painless common peroneal neuropathy. Magnetic resonance imaging (MRI) revealed nerve thickening and enhancement, while a positron emission tomography (PET) scan demonstrated increased fluorodeoxyglucose uptake in a large segment of the neurovascular bundle, suggesting peripheral nerve infiltration. Both findings resolved following treatment with chemotherapy that crossed the blood-nerve barrier. In selected patients presenting with peripheral neuropathy, MRI and PET scan can be helpful in the diagnosis of peripheral nerve infiltration.