Successful treatment of influenza B associated acute necrotizing encephalopathy in an adult using combination of high dose oseltamivir-IVIG-pulse metylprednisolone

Polymyalgia Rheumatica Following Influenza B Infection: A Case Report

We describe a case of polymyalgia rheumatica (PMR) following an influenza B infection. The patient was a 71-year-old woman who developed a fever above 38.0°C and was diagnosed with influenza B, confirmed by a rapid antigen test. Although the fever resolved after three days, she continued to experience neck pain, back pain, and joint pain, particularly in both shoulders and hips. She also reported morning joint stiffness lasting for more than an hour and occasional low-grade fever. She presented to our hospital 25 days after the onset of symptoms. Blood tests revealed elevated C-reactive protein and erythrocyte sedimentation rate, but levels of creatine phosphokinase, rheumatoid factor, and anti-cyclic citrullinated peptide were not elevated. She was diagnosed with PMR and treated with prednisolone (PSL) 15 mg/day. The response to steroids was remarkably good, and PSL was tapered over six months. PMR is believed to result from an immune-mediated process and may be associated with certain human leukocyte antigen haplotypes. Additionally, PMR is sometimes preceded by an infection. To date, there have been very few reports suggesting a connection between influenza B and PMR, underscoring the need for further case accumulation.

Acute necrotizing encephalopathy in adult patients with influenza: a case report and review of the literature

The neurological complications of influenza affect mainly the pediatric Asian population. In the category of influenza-associated encephalopathy, acute necrotizing encephalopathy (ANE) is a rapidly progressive and fulminant brain disorder associated with significant neurological sequelae and mortality. To date, only a few adult cases of influenza-associated ANE have been reported. We describe a 44-year-old woman who presented with rapid progression of consciousness impairment and recurrent generalized convulsions. Influenza was diagnosed three days prior to presentation, and infection with influenza A (H3N2) pdm09 was subsequently confirmed. A diagnosis of ANE was made based on the presence of characteristic brain MRI findings, the exclusion of central nervous system infection, and an elevated serum interleukin-6 level. Pulse steroid therapy followed by tocilizumab was initiated, which led to clinical stabilization and improvement. Genetic testing revealed that the patient carried heterozygous human leukocyte antigen DQB1 03:03 and DRB1 09:01 genotypes. An analysis of the adult cases of influenza-associated ANE in the literature and the present case revealed a wide range of ages (22-71 years), a short interval (median 3 days) between the clinical onset of influenza and ANE, and a high overall mortality rate (32%). The thalamus was the most frequent (91%) location of the lesions. Our report highlights the importance of identifying this devastating but treatable neurological complication of influenza in adults, especially those of Asian descent. As a cytokine storm is the most accepted pathogenic mechanism for ANE, cytokine-directed therapies may be promising treatments for which further investigation is warranted.

Pathogenesis and Management of Acute Necrotizing Encephalopathy

INTRODUCTION

During the COVID-19 pandemic, many cases of acute necrotizing encephalopathy (ANE) secondary to COVID-19 have been reported. ANE is characterized by a rapid onset, a fulminant course, and low morbidity and fatality rates. Therefore, clinicians need to be vigilant for such disorders, especially during the influenza virus and COVID-19 epidemics.

AREAS COVERED

The authors summarize the most recent studies on the clinical spectrum and treatment essentials of ANE to provide references for prompt diagnosis and improved treatment of this rare but fatal disease.

EXPERT OPINION

ANE is a type of necrotizing lesion of the brain parenchyma. There are two major types of reported cases. One is isolated and sporadic ANE, which is primarily caused by viral infections, particularly influenza and HHV-6 virus. The other type is familial recurrent ANE, which is caused by RANBP2 gene mutations. ANE patients have rapid progression and a very poor prognosis, with acute brain dysfunction occurring within days of viral infection and requiring admission to the intensive care unit. Clinicians still need to investigate and find solutions for the problems of early detection and treatment of ANE.