Hepatitis C virus infection and myositis: a polymerase chain reaction study

Extrahepatic Manifestations of Chronic Hepatitis C Virus (HCV) Infection

Hepatitis C virus (HCV) is a well-recognized, major cause of various liver-related conditions such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Apart from liver disease, chronic HCV infection is also associated with several extrahepatic manifestations that can lead to significant morbidity and mortality. These extrahepatic manifestations include essential mixed cryoglobulinemia (EMC), lymphomas, porphyria cutanea tarda, lichen planus, necrolytic acral erythema, glomerulonephritis, subclinical autoantibody formation, immune thrombocytopenia, thyroid disease, Sjögren's disease/sicca symptoms, diabetes mellitus, ocular diseases, musculoskeletal disorders, cardiovascular diseases, neurocognitive dysfunction, and leukocytoclastic vasculitis. We are presenting a case of chronic HCV infection linked to the extrahepatic manifestations of the disease which can be directly related to HCV or indirectly related to EMC from HCV. An awareness and knowledge of these extrahepatic manifestations will highlight the importance of recognizing the symptoms for an early diagnosis and effective anti-viral treatment in order to improve or resolve the long-term complications of chronic HCV infection.

Paraspinal Myositis in Patients with COVID-19 Infection

Myalgia is a previously reported symptom in patients with COVID-19 infection; however, the presence of paraspinal myositis has not been previously reported. We report MR imaging findings of the spine obtained in a cohort of 9 patients with COVID-19 infection who presented to our hospital between March 3, 2020 and May 6, 2020. We found that 7 of 9 COVID-19 patients (78%) who underwent MR imaging of the spine had MR imaging evidence of paraspinal myositis, characterized by intramuscular edema and/or enhancement. Five of these 7 patients had a prolonged hospital course (greater than 25 days). Our knowledge of the imaging manifestations of COVID-19 infection is expanding. It is important for clinicians>a to be aware of the relatively high frequency of paraspinal myositis in this small cohort of patients with COVID-19 infection.

Metabolic Dysregulation in Hepacivirus Infection of Common Marmosets (Callithrix jacchus)

Chronic hepatitis C has been associated with metabolic syndrome that includes insulin resistance, hepatic steatosis and obesity. These metabolic aberrations are risk factors for disease severity and treatment outcome in infected patients. Experimental infection of marmosets with GBV-B serves as a tangible, small animal model for human HCV infection, and while virology and pathology are well described, a full investigation of clinical disease and the metabolic milieu is lacking. In this study six marmosets were infected intravenously with GBV-B and changes in hematologic, serum biochemical and plasma metabolic measures were investigated over the duration of infection. Infected animals exhibited signs of lymphocytopenia, but platelet and RBC counts were generally stable or even increased. Although most animals showed a transient decline in blood glucose, infection resulted in several fold increases in plasma insulin, glucagon and glucagon-like peptide 1 (GLP-1). All infected animals experienced transient weight loss within the first 28 days of infection, but also became hypertriglyceridemic and had up to 10-fold increases in adipocytokines such as resistin and plasminogen activator inhibitor 1 (PAI-1). In liver, moderate to severe cytoplasmic changes associated with steatotic changes was observed microscopically at 168 days post infection. Collectively, these results suggest that GBV-B infection is accompanied by hematologic, biochemical and metabolic abnormalities that could lead to obesity, diabetes, thrombosis and atherosclerosis^, even after virus has been cleared. Our findings mirror those found in HCV patients, suggesting that metabolic syndrome could be conserved among hepaciviruses, and both mechanistic and interventional studies for treating HCV-induced metabolic complications could be evaluated in this animal model.

Neuromuscular diseases associated with chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection is a growing international health problem, and more than 170 million people are chronic carriers. Up to 50% of HCV-positive patients develop at least one extrahepatic manifestation during the course of disease. To varying degrees of certainty, there is evidence of an association between chronic HCV infection and a variety of neuromuscular diseases. The pathogenesis of most extrahepatic diseases remains unclear but possibly includes HCV lymphotropism and/or HCV-induced autoantibodies. The therapeutic approach to HCV-associated autoimmune disorders entails eradication of HCV with one of the recombinant interferon-alpha preparations with or without additional immunosuppressive drugs.

HCV-related nervous system disorders

Chronic infection with hepatitis C virus (HCV) is associated with a wide spectrum of extrahepatic manifestations, affecting different organ systems. Neurological complications occur in a large number of patients and range from peripheral neuropathy to cognitive impairment. Pathogenetic mechanisms responsible for nervous system dysfunction are mainly related to the upregulation of the host immune response with production of autoantibodies, immune complexes, and cryoglobulins. Alternative mechanisms include possible extrahepatic replication of HCV in neural tissues and the effects of circulating inflammatory cytokines and chemokines.

Hepatitis C virus does not infect muscle, the intervertebral disk, or the meniscus in patients with chronic hepatitis C

Chronic infection with hepatitis C virus (HCV) is associated with several extrahepatic manifestations, including neuromuscular and joint disorders, and HCV RNA has been detected in muscle fibers of patients with myosistis and chronic hepatitis C. However, whether HCV infects muscle cells in patients without myosistis is unknown. The presence of HCV in other sites of the musculoskeletal system has not been investigated. In the present study the presence of HCV RNA was sought in muscle (2 cases), intervertebral disk (1 case) and meniscus (1 case) samples from patients with chronic hepatitis C. HCV RNA was not detected by reverse transcription and real-time polymerase chain reaction in any of the samples tested. In conclusion, the results do not support a direct role of HCV in musculoskeletal disorders associated with chronic hepatitis C.

West Nile virus encephalitis with myositis and orchitis

This report documents the hospital course and autopsy findings of a 43-year-old man with a renal allograft who died of West Nile virus (WNV) encephalitis. Central nervous system (CNS) findings were those of severe necrotizing and hemorrhagic encephalitis affecting gray matter regions limited to the diencepahlon, rhombencephalon, spinal cord, and limbic system. The bilateral process exhibited preferential involvement of motor neurons. Brain imaging obtained 6 days before death demonstrated an unusual pattern of involvement corresponding with the autopsy findings, confirming that imaging may be a specific diagnostic guide in WNV encephalitis. Extra-CNS findings include myositis with T-lymphocyte infiltration of nerve fibers, suggesting that the virus may reach the CNS via peripheral nerves. Orchitis with dense T-lymphocyte infiltration and syncytial cell formation thought to be due to WNV were also noted.

Hepatitis C virus infection and myositis: a virus localization study

We report a case of myositis associated with chronic hepatitis C virus infection. Muscle biopsy and immunohistochemistry showed perifascicular atrophy, few necrotic and regenerating fibres, scarce perivascular infiltrates, deposits of immunoglobulin G, C3, fibrinogen and MAC in muscle vessel walls, and non-uniform expression of major histocompatibility complex-I antigens among muscle fibres. Hepatitis C virus NS3 antigen and hepatitis C virus RNA were detected in infiltrating cells but not within muscle fibres or endothelial cells. Our findings suggest that humoral-mediated immune mechanisms, not directly related to hepatitis C virus infection of muscle structures, may sustain the local inflammatory reaction in this patient.

Genetic and environmental risk factors for idiopathic inflammatory myopathies

Although the studies discussed are beginning to reveal a number of genetic and possible environmental risk factors for myositis, further investigations are needed to fully understand and classify these syndromes. The difficulties in this process include small numbers of subjects with varying disease phenotypes available for study, polygenic risk factors for which it remains unclear which are primary and which are secondary or linked genes, and the lack of validated environmental exposure assessment tools. New technologies and international collaborative approaches, however, may overcome some of these difficulties and allow us to identify genetic and environmental risk factors, as well as the critical gene-environment interactions in the IIM and its subgroups. Nonetheless, our understanding of these diseases is still in the early stages. Although we have learned a great deal about these disorders through detailed investigations over the last several decades, we have even further to go to understand the environmental triggers and genetic susceptibilities for the myositis syndromes.

Inclusion body myositis associated with hepatitis C virus infection

The case of a 77-year-old woman with hepatitis C virus infection with a 5-year history of muscle weakness and mild disturbance of gait is reported. Steroid therapy did not improve her symptoms. She developed HCV-related liver cirrhosis and hepatocellular carcinoma, and muscle biopsy revealed inclusion body myositis. Immunohistochemistry showed that the nonstructural region of HCV and 8-hydroxy-2'-deoxyguanosine, a marker of DNA damage by reactive oxygen species, were present in striated muscle cells of this patient.