Background: Influenza-associated encephalopathy, encephalitis, and acute necrotizing encephalopathy (ANE) are rare but potentially life-threatening neurological complications of influenza. Adult cases remain poorly characterized because the available literature is largely limited to isolated case reports and small case series. Methods: A PRISMA-guided scoping review of the MEDLINE database was conducted through 31 May 2026. Published adult cases of influenza-associated encephalopathy, encephalitis, and ANE were identified and analyzed for demographic characteristics, clinical presentation, neuroimaging findings, treatment, and outcomes. Results: Eighty-three adult cases reported between 1958 and 2026 were included. The mean age was 45.6 ± 17.8 years, and 57.8% were male. Two-thirds did not have any underlying comorbidities. Neurological symptoms developed a mean of 4.6 days after influenza onset, with influenza A accounting for 80.7% of infections. Fever (91.6%), altered mental status (86.7%), and seizures (36.1%) were the most common manifestations. Encephalitis was the predominant presentation (44.5%), followed by encephalopathy (31.3%) and ANE (24.1%). MRI most frequently demonstrated cerebral hemispheric lesions (53.0%) and bilateral thalamic involvement (36.4%), while EEG abnormalities were reported in 69.6% of patients. Overall mortality was 22.9%, highest among patients with ANE (45.0%). Among survivors, 28.9% experienced persistent neurological sequelae. Conclusions: Influenza-associated encephalopathy, encephalitis, and ANE are rare in adults but are associated with substantial morbidity and mortality. This review represents the largest adult cohort reported to date and provides important insights into the clinical spectrum, neurodiagnostic findings, and outcomes of these uncommon complications. This review highlights significant gaps in knowledge and the need for collaborative multicenter studies to improve the diagnosis, treatment, and outcome of these severe complications of influenza infection.
Adrenal Abscesses: A Systematic Review of the Literature
Objective: To summarize the existing knowledge about adrenal gland abscesses, including etiology, clinical presentation, common laboratory and imaging findings, management and overall morbidity and mortality. Design: Systematic literature review. Methods: We performed a search in the PubMed database using search terms: ‘abscess and adrenal glands’, ‘adrenalitis’, ‘infection and adrenal gland’, ‘adrenal abscess’, ‘adrenal infection’ and ‘infectious adrenalitis’. Articles from 2017 to 2022 were included. We found total of 116 articles, and after applying exclusion criteria, data from 73 articles was included in the final statistical analysis. Results: Of 84 patients included in this review, 68 were male (81%), with a mean age of 55 years (range: 29 to 85 years). Weight loss was the most frequent symptom reported in 58.3% patients, followed by fever in 49%. Mean duration of symptoms was 4.5 months. The most common laboratory findings were low cortisol (51.9%), elevated ACTH (43.2%), hyponatremia (88.2%) and anemia (83.3%). Adrenal cultures were positive in 86.4% cases, with Histoplasma capsulatum (37.3%) being the leading causative agent. Blood cultures were positive in 30% of patients. The majority of the adrenal infections occurred through secondary dissemination from other infectious foci and abscesses were more commonly bilateral (70%). A total of 46.4% of patients developed long-term adrenal insufficiency requiring treatment. Abscess drainage was performed in 7 patients (8.3%) and adrenalectomy was performed in 18 (21.4%) patients. The survival rate was 92.9%. Multivariate analysis showed that the only independent risk factor for mortality was thrombocytopenia (p = 0.048). Conclusion: Our review shows that adrenal abscesses are usually caused by fungal pathogens, and among these, Histoplasma capsulatum is the most common. The adrenal glands are usually involved in a bilateral fashion and become infected through dissemination from other primary sources of infection. Long-term adrenal insufficiency develops in 46% of patients, which is more common than what is observed in non-infectious etiology of adrenal gland disorders. Mortality is about 7%, and the presence of thrombocytopenia is associated with worse prognosis. Further prospective studies are needed to better characterize optimal testing and treatment duration in patients with this relatively rare but challenging disorder.
Fusobacterium necrophorum subsp. necrophorum Liver Abscess with Pylephlebitis: An Abdominal Variant of Lemierre’s Syndrome
Liver abscess associated with suppurative portal vein thrombosis (pylephlebitis) secondary to Fusobacterium necrophorum has been rarely reported. It is considered to be an abdominal variant of Lemierre’s syndrome associated with significant morbidity and mortality. We report a case of 69-year-old man who developed liver abscess and pylephlebitis due to F. necrophorum with an unclear source of infection. We discuss the pathogenesis, diagnosis, and treatment strategy for this entity, with a review of previously published cases of pyelephlebitis due to F. necrophorum in regard to their clinical presentation and outcome.