A study of acute muscle dysfunction with particular reference to dengue myopathy

Japanese encephalitis virus infection causes reactive oxygen species-mediated skeletal muscle damage

Skeletal muscle wasting is a clinically proven pathology associated with Japanese encephalitis virus (JEV) infection; however, underlying factors that govern skeletal muscle damage are yet to be explored. The current study aims to investigate the pathobiology of skeletal muscle damage using a mouse model of JEV infection. Our study reveals a significant increment in viral copy number in skeletal muscle post-JEV infection, which is associated with enhanced skeletal muscle cell death. Molecular and biochemical analysis confirms NOX2-dependent generation of reactive oxygen species, leading to autophagy flux inhibition and cell apoptosis. Along with this, an alteration in mitochondrial dynamics (change in fusion and fission process) and a decrease in the total number of mitochondria copies were found during JEV disease progression. The study represents the initial evidence of skeletal muscle damage caused by JEV and provides insights into potential avenues for therapeutic advancement.

Association Between a History of Dengue Fever and the Risk of Systemic Autoimmune Rheumatic Diseases: A Nationwide, Population-Based Case-Control Study

Purpose: To determine the association between a history of clinically diagnosed dengue infection and the risk of systemic autoimmune rheumatic diseases (SARDs). Methods: Using claims data from the 1997-2013 Taiwanese National Health Insurance Research Database, we included 74,422 patients who were diagnosed with SARDs and 297,688 patients without SARDs who were matched (in a 1:4 ratio) for age, sex, year of SARDs index date, and city of residence. The associations between the development of SARDs and a history of dengue infection (International Classification of Diseases, Ninth Revision, Clinical Modification code 061) were investigated using conditional logistic regression analysis shown as odds ratios (ORs) with 95% confidence intervals (CIs) after adjusting for potential confounders. Results: We included 17,126 patients with systemic lupus erythematosus (SLE), 15,531 patients with Sjogren's syndrome (SS), 37,685 patients with rheumatoid arthritis (RA), 1,911 patients with systemic sclerosis (SSc), 1,277 patients with dermatomyositis (DM), and 892 patients with polymyositis (PM). SLE (OR, 4.55; 95% CI, 2.77-7.46; p <0.001) risk was significantly associated with a history of dengue infection. However, no statistically significant association was found between dengue infection and SS (OR, 1.41; 95% CI, 0.88-2.26; p = 0.155), RA (OR, 1.03; 95% CI, 0.70-1.50; p = 0.888), SSc (OR, 1.97; 95% CI, 0.38-10.29; p = 0.420), DM (OR, 0.54; 95% CI, 0.04-7.27; p = 0.641), or PM (OR, 2.08; 95% CI, 0.23-18.79; p = 0.513). Conclusion: This study revealed that a history of dengue infection was significantly associated with the risk of SLE, but not SS, RA, SSc, DM, or PM.

Dengue fever presenting with severe myositis-An unusual presentation

Dengue fever is an arbovirus (dengue virus DEN) disease caused by bite of mosquitoes, affecting people worldwide but is frequently seen as pandemic in Latin America and Asian countries. Among children it has been the most frequent reason for hospitalization and mortality. Symptoms range from subclinical disease to severe flu-like illness including myalgias. Dengue commonly presents as myalgia but myositis and/or elevated serum creatine phosphokinase (CPK) is rarely witnessed in dengue fever. Therefore, we present a case of dengue fever presenting as myositis: muscle weakness with raised creatine phosphokinase (CPK).

[Serum activity of CK and CK-MB in patients with dengue virus infection]

OBJECTIVE

To determine the serum activity of CK and CK-MB in patients with dengue infection.

METHODS

A cross section study was conducted in the State of Antioquia, Colombia. The study population consisted in 54 patients with diagnosis of dengue infection and 10 healthy controls. A blood sample was taken from all participants to confirm dengue infection and to measure the activity of CK and CK-MB.

RESULTS

The median age of dengue cases was 18 years and the median age of healthy controls was 28.5 years. Half of dengue patients (50.9 %) had elevated levels of CK-MB, in contrast with the healthy controls in which none presented increase of this enzyme. No patient presented myocarditis; however, elevated CK-MB was observed in 33.3 %, 44.4 % and 40 % of cases with bradycardia, tachycardia and hypotension respectively. In 29.6 % of the dengue patients, high level of CK was detected, in contrast to 10 % in the control group. Activity of CK elevated was observed in dengue patients with symptoms such as vomiting, hematemesis and abdominal pain, 87.5 %, 60 % and 50 %, respectively.

CONCLUSIONS

In this study, no patient with dengue infection had heart disease or myositis; however, the finding of a higher frequency of elevated level CK and CK-MB in the dengue patients compared to the control group suggests the involvement of the striated muscle and of the cardiac muscle in this group. For this reason, the monitoring of these enzymes should be considered as part of the monitoring of patients with dengue.