Lower respiratory tract viral infections: Diagnostic role of exfoliative cytology

Oral candidiasis in patients hospitalised in the intensive care unit: Diagnosis through clinical and cytopathological examinations

OBJECTIVE

To evaluate the prevalence and clinical aspects of oral candidiasis in patients hospitalised in the intensive care unit.

METHODS

This is a longitudinal and prospective study that included 48 participants hospitalised in the intensive care unit. Sociodemographic data, presence of systemic disorders, use of medications, laboratory tests, cause of hospital admission, type of breathing, and length of hospital stay were obtained from medical records. Oral clinical inspection and cytopathological examinations were performed on all participants. The diagnosis of clinical candidiasis was based on the presence of clinical alterations together with positive cytopathological examination results. The diagnosis of subclinical candidiasis was based on the absence of clinical lesions and a positive cytopathological examination. The absence of oral candidiasis was considered when the participant did not present oral lesions and had a negative cytopathological examination.

RESULTS

Clinical candidiasis was present in 18.8% of the 48 participants, and 45.8% of them had the subclinical form. Levels of urea (P = 0.005), creatinine (P = 0.009), haemoglobin (P = 0.009), haematocrit (P = 0.011), bands (P = 0.024), international normalised ratio (INR; P = 0.034), types of breathing (P = 0.017), length of hospital stay (P = 0.037), and outcome (P = 0.014) demonstrated statistically significant differences between the groups with and without oral candidiasis.

CONCLUSIONS

Clinical and subclinical forms of oral candidiasis are frequent in intensive care unit patients. Levels of urea, creatinine, haemoglobin, haematocrit, bands, INR, type of breathing, length of hospital stay, and outcome can be associated with the presence of candidiasis.

Broad Ultrastructural and Transcriptomic Changes Underlie the Multinucleated Giant Hemocyte Mediated Innate Immune Response against Parasitoids

Multinucleated giant hemocytes (MGHs) represent a novel type of blood cell in insects that participate in a highly efficient immune response against parasitoid wasps involving isolation and killing of the parasite. Previously, we showed that circulating MGHs have high motility and the interaction with the parasitoid rapidly triggers encapsulation. However, structural and molecular mechanisms behind these processes remained elusive. Here, we used detailed ultrastructural analysis and live cell imaging of MGHs to study encapsulation in Drosophila ananassae after parasitoid wasp infection. We found dynamic structural changes, mainly driven by the formation of diverse vesicular systems and newly developed complex intracytoplasmic membrane structures, and abundant generation of giant cell exosomes in MGHs. In addition, we used RNA sequencing to study the transcriptomic profile of MGHs and activated plasmatocytes 72 h after infection, as well as the uninduced blood cells. This revealed that differentiation of MGHs was accompanied by broad changes in gene expression. Consistent with the observed structural changes, transcripts related to vesicular function, cytoskeletal organization, and adhesion were enriched in MGHs. In addition, several orphan genes encoding for hemolysin-like proteins, pore-forming toxins of prokaryotic origin, were expressed at high level, which may be important for parasitoid elimination. Our results reveal coordinated molecular and structural changes in the course of MGH differentiation and parasitoid encapsulation, providing a mechanistic model for a powerful innate immune response.

Tissue Pathogens and Cancers: A Review of Commonly Seen Manifestations in Histo- and Cytopathology

Tissue pathogens are commonly encountered in histopathology and cytology practice, where they can present as either benign mimickers of malignancy or true malignancies. The aim of this review is to provide a timely synthesis of our understanding of these tissue pathogens, with an emphasis on pertinent diagnostic conundrums associated with the benign mimickers of malignancy that can be seen with viral infections and those which manifest as granulomas. The oncogenic pathogens, including viruses, bacteria, and parasites, are then discussed with relationship to their associated malignancies. Although not exhaustive, the epidemiology, clinical manifestations, pathogenesis, and histological findings are included, along with a short review of emerging therapies.

Viral Respiratory Pathogens and Lung Injury

Several viruses target the human respiratory tract, causing different clinical manifestations spanning from mild upper airway involvement to life-threatening acute respiratory distress syndrome (ARDS). As dramatically evident in the ongoing SARS-CoV-2 pandemic, the clinical picture is not always easily predictable due to the combined effect of direct viral and indirect patient-specific immune-mediated damage. In this review, we discuss the main RNA (orthomyxoviruses, paramyxoviruses, and coronaviruses) and DNA (adenoviruses, herpesviruses, and bocaviruses) viruses with respiratory tropism and their mechanisms of direct and indirect cell damage. We analyze the thin line existing between a protective immune response, capable of limiting viral replication, and an unbalanced, dysregulated immune activation often leading to the most severe complication. Our comprehension of the molecular mechanisms involved is increasing and this should pave the way for the development and clinical use of new tailored immune-based antiviral strategies.

Critical values in cytology

The timely reporting of critical values, or values that may be life-threatening if immediate action is not taken, is essential to patient care and safety. Although some guidelines exist for critical diagnoses in cytology, not all laboratories have a specific list of diagnoses that should be considered critical, and the very existence of cytology "critical values" has been called into question. Here we propose a pragmatic system for determining cytology critical values and report our laboratory's critical value list, formulated based on a review of the medical literature regarding clinical urgency and other institutions' cytology critical value lists.

Diagnosis of Infectious Diseases in the Lower Respiratory Tract: A Cytopathologist's Perspective

CONTEXT.—

Respiratory cytology continues to play an important role in the diagnosis of lower respiratory tract infections. Prompt, accurate diagnosis of causative organisms is of paramount importance, particularly in immunosuppressed patients. In addition, a rapidly expanding arsenal of ancillary testing is now available, aiding tremendously in organism identification.

OBJECTIVE.—

To provide an updated review on the cytomorphologic features of common organisms in lower respiratory tract infection. Relevant ancillary tests, differential diagnoses, and potential pitfalls of organism identification will also be discussed.

DATA SOURCES.—

Data for this review were gathered from PubMed searches of infectious diseases of the lower respiratory tract, especially related to the diagnoses.

CONCLUSIONS.—

The lower respiratory tract is subject to infection by a wide variety of infectious agents. Pathologists should be familiar with common organisms, including their general clinical characteristics, cytomorphologic features, differential diagnoses, and ancillary methods of detection. Above all, correlation with microbiologic and clinical information is necessary to make a confident diagnosis of infection.