VSC310 Pathobiology: Key Concepts

• VSC310 Principles of Pathobiology is taught by Shubho Das DVM MSc PhD.
• The course includes lectures and practicals with multiple choice questions (MCQs) and covers key topics such as vascular disturbances, inflammation, and immunopathology.
• The assessment is 50% in-session MCQs and 50% a short questions theory exam, which is invigilated.

Key Concepts in Pathology

• Pathology is the study of disease and its mechanisms within living tissues, focusing on structural and functional abnormalities.
• A lesion is any measurable abnormal state in the body and its presence denotes disease.
• Lesions can be detected grossly, histologically, or biochemically.
• A small lesion can have major consequences depending on its location

Defining Health vs. Disease

• Health is defined as a state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity, according to the WHO.
• Health doesn't necessarily mean the absence of disease, but rather a condition of optimal well-being.
• Disease is recognized as a departure from a state of health, indicated by structural or functional abnormalities, i.e lesions.

Consequences of Disease

• Consequences of disease can include organ failure, impaired mechanical function, pain, or systemic metabolic effects.
• In some cases, there may be no visible consequence.
• Functional reserve capacity plays a key role in determining the clinical manifestation of disease.

Pathology and Pathogenesis

• An understanding of pathology and disease processes (pathogenesis) is crucial for diagnosing and treating disease.
• Key questions include where the disease is, how the process occurs, what the cause is, and the likely progression and prognosis.

Branches of Pathology

• Clinical Pathology includes haematology, clinical biochemistry, urinalysis/fluid analysis, and cytology.
• Anatomical Pathology includes biopsy, necropsy, gross pathology, and histopathology.
• Other branches include bacteriology, virology, mycology, immunology and parasitology.

Observation Skills

• Recognition of abnormalities requires a good knowledge of what is normal.
• An ability to describe abnormalities or lesions is key.

Time Scale of Disease

• Clinical or subclinical disease depends on various factors, mostly centred on the lesion and functional reserve capacity.
• Acute diseases start rapidly and progress quickly, while chronic diseases progress slowly over a longer period.

Stages of Diagnostic Pathology

• Diagnostic Pathology involves accurately observing what is before you, using all senses (except taste) during gross pathology.
• It also involves determining what is normal or abnormal.
• Describe any abnormalities and provide a morphological description.
• An important stage is to interpret the underlying pathological processes responsible for the abnormalities.
• Summarize the findings into a morphological diagnosis and prepare a pathology report to direct deductive reasoning, suggest diagnostic modality, guide sample selection, offer a picture to pathologists, help with prognostic variables, select treatment, and create a medicolegal record.

Morphological Description

• Elements of morphological description include the location and extent, distribution, size, shape, color, surface, consistency, and any special features.
• It is important to avoid interpretation at this stage.
• It is important not to use the word "lesion" while describing, instead of holding it back for the report.
• Morphology consists of types of shape and patterns like eroded, ulcerated, lacerated etc.
• Morphology can also consist of alveolar, basaloid and chicken wire shapes and patterns.

Morphological Diagnosis

• This comprises the pathological process with descriptors.
• Processes include disturbances of growth (adaptive rex, neoplasia, teratology), circulatory, inflammatory, degeneration/necrosis or pigmentary changes.
• Descriptors of the process may include severity (severe, moderate, mild), chronicity (peracute, acute, subacute, chronic), distribution (diffuse, focal, multifocal, focal/locally extensive, segmental), and the classification of the process (e.g., pyogranulomatous, suppurative).

Overview of Disease Processes

• Key mechanisms of disease include adaptive tissue responses, vascular disturbances, inflammation, healing and repair, cell degeneration with or without necrosis, neoplasia, and teratology.