This is the first study of MG in Latvia and the second population-based study of MG in Eastern Europe. Our epidemiological results are similar to those in some other European and Northern American countries, and show high prevalence and increasing incidence of late-onset MG.

Structural and ultrastructural alterations in human olfactory pathways and putative associations with human herpesvirus 6 (HHV-6) infection were studied. The olfactory bulb/tract samples from 20 subjects with an unspecified encephalopathy determined by pathomorphological examination of the brain autopsy, 17 healthy age-matched and 16 younger controls were used. HHV-6 DNA was detected in 60, 29, and 19% of cases in these groups, respectively. In the whole encephalopathy group, significantly more HHV-6 positive neurons and oligodendrocytes were found in the gray matter, whereas, significantly more HHV-6 positive astrocytes, oligodendrocytes, microglia/macrophages and endothelial cells were found in the white matter. Additionally, significantly more HHV-6 positive astrocytes and, in particular, oligodendrocytes were found in the white matter when compared to the gray matter. Furthermore, when only HHV-6 PCR+ encephalopathy cases were studied, we observed similar but stronger associations between HHV-6 positive oligodendrocytes and CD68 positive cells in the white matter. Cellular alterations were additionally evidenced by anti-S100 immunostaining, demonstrating a significantly higher number of S100 positive cells in the gray matter of the whole encephalopathy group when compared to the young controls, and in the white matter when compared to both control groups. In spite the decreased S100 expression in the PCR+ encephalopathy group when compared to PCR- cases and controls, groups demonstrated significantly higher number of S100 positive cells in the white compared to the gray matter. Ultrastructural changes confirming the damage of myelin included irregularity of membranes and ballooning of paranodal loops. This study shows that among the cellular targets of the nervous system, HHV-6 most severely affects oligodendrocytes and the myelin made by them.

During the COVID-19 pandemic, healthcare systems have faced unprecedented pressures. One challenge has been to promptly recognise non-COVID-19 conditions. Cognitive bias due to the availability heuristic may cause difficulties in reaching the correct diagnosis. Confirmation bias may also affect imaging interpretation. We report three cases with an alternative final diagnosis in whom COVID-19 was initially suspected: (a) Pneumocystis jirovecii pneumonia with unrecognised HIV infection; (b) pulmonary lymphangitis carcinomatosis; and (c) ST elevation myocardial infarction causing acute pulmonary oedema. To help mitigate bias, there is no substitute for thoughtful clinical assessment and critical appraisal when evaluating new information and formulating the differential diagnosis

Myasthenia gravis (MG) is an autoimmune disease characterized by autoantibody mediated postsynaptic failure of neuromuscular transmission. The thymus gland has a role in the pathogenesis of MG. The aim of this study was to determine (1) the prevalence of different thymic pathologies in the MG patient population of Latvia; (2) the potential impact of different thymus pathologies on the clinical course of MG; and (3) the effectiveness of surgical treatment of thymic pathologies in Latvia. The results showed that the most common thymus pathology among the patients with MG in Latvia is thymoma. Compared to the published data, the proportion of MG patients diagnosed with thymus hyperplasia in Latvia is very small. Thymus hyperplasia is uncommon among patients 60 years of age and older. MG onset for patients with thymoma is significantly later than that of patients with thymus hyperplasia. Almost all patients with thymoma or thymus hyperplasia develop a generalised form of MG. The presence of a thymus pathology does not significantly affect the electrophysiological test results, clinical symptom severity, frequency of disability or hospitalisation of the patients with MG. Thymectomy in patients with thymoma or thymus hyperplasia has no significant effect on relieving MG symptoms