Pathology First Exam 2024 Material

Pathology First Exam 2024 Material

• The exam material covers concepts of health and disease, encompassing etiology, pathogenesis, morphology, clinical manifestations, diagnosis, and clinical course.
• Pathology is the study of disease, with pathos meaning disease and physiology relating to function.
• Health is defined as "a state of complete physical, mental, and social well-being and not merely the absence of disease and infirmity."
• Disease is an interruption or disorder in the function of the body, an organ, or system (physiological dysfunction).
• The disease process has six aspects: etiology (causes), pathogenesis (mechanism), morphological changes, clinical manifestations (signs and symptoms), diagnosis, and clinical course.
• Etiologic factors are the causes of disease, ranging from biological agents (bacteria, viruses), physical forces (trauma, burn, radiation), chemical agents (poisons, alcohol), genetic inheritance, to nutritional excesses or deficits.
• Most diseases are multifactorial, stemming from multiple contributing factors, not a single cause. Some disease-causing agents are unspecified (idiopathic).
• Risk factors predispose to or increase the risk of a disease (e.g., obesity, increasing risk of heart disease).
• Congenital conditions are defects present at birth, whereas acquired defects arise from events after birth. Examples include sickle cell anemia and exposure to infections (e.g., HBV).
• Pathogenesis details the sequence of cellular and tissue events from initial contact with an etiologic agent until the expression of the disease.
• Atherosclerosis is an example, where the cause is the disease, and the pathogenic process is the progression of the disease.
• Morphology refers to the fundamental structure and form of cells and tissues, focusing on gross anatomic and microscopic changes characteristic of diseases.
• Histology studies cells and the extracellular matrix of tissues, playing a role in diagnosing many types of cancer.
• Disease manifestations include symptoms (subjective complaints) and signs (objective observations). Symptoms can range from pain to difficulty breathing. Signs might include elevated temperature or a rash.
• Diagnosis involves identifying the cause of a disease through patient history, physical examination, and laboratory tests. A rationale for lab tests includes validating problems and/or confirming a diagnosis, determining related health problems.
• Clinical course describes the evolution of a disease over time and includes acute, subacute, and chronic stages. Acute diseases are typically severe and self-limiting; chronic diseases are continuous and vary in severity. Subacute is between acute and chronic.
• Pathophysiology bridges basic science and clinical medicine.
• Clinical course includes various disease severities for infectious diseases that can range from clinical disease (signs and symptoms), pre-clinical stage (no signs and symptoms, but transmissible), subclinical disease (not clinically evident), to healthy/passive carriers (harboring an organism, but not infected evidenced by an antibody response) and active carriers (infected individuals transmissible).
• Epidemiology studies disease occurrence and spread in populations, involving risk factors (e.g. smoking, alcohol), and patterns related to factors such as age, race, and lifestyle..
• Incidence is the number of new cases in a population over a period, while prevalence includes both new and pre-existing cases within a population at a given time point.
• Mortality statistics cover death numbers due to disease, and morbidity considers the effects (clinical course) of a disease on a person's life.
• Cellular adaptation, injury, and death are pivotal concepts.
• Cells maintain homeostasis, adapting to stressors and threats like physiologic stimulus (e.g., pregnancy-related hormonal changes) and pathologic stimulus (e.g., disease). Cell adaptations include hypertrophy (increased size), hyperplasia (increased number), atrophy (reduced size), metaplasia (changing cell type).
• Cell injury can be caused by various factors, including physical agents (mechanical forces, temperature extremes, electrical forces), radiation, chemicals, biological agents, and nutritional imbalances.
• Mechanisms of cell injury include free radical formation, hypoxia/ATP depletion, and disruption of intracellular calcium homeostasis.
• Oxidative stress occurs when free radical formation exceeds the body's ability to neutralize them; hypoxia (lack of oxygen) impairs ATP production; and intracellular calcium dysregulation can damage cellular components. This can result in necrosis, which is cell death characterized by inflammation, or apoptosis, a programmed cell death.
• Neoplasia, the uncontrolled proliferation of cells, forms tumors (neoplasms). Benign tumors are well-differentiated, grow slowly, and remain localized. In contrast, malignant tumors are poorly differentiated, grow aggressively, and can metastasize. Nomenclature is important (e.g., adenoma vs adenocarcinoma). Carcinoma in situ is a pre-invasive lesion.
• Carcinogenesis is the multistage process of normal to cancerous cells, involving initiation (DNA damage), promotion (unregulated proliferation), and progression (additional genetic mutations). Factors that can cause gene mutations are inherited factors, chemical carcinogens, viruses, and/or chemical instability of DNA.
• Pathologic descriptions of tumor characteristics include a local increase in cell number, loss of normal cell arrangement and shape, variation in shape/size, and increase in nuclear size and density, with notable increases in mitotic activity.
• Malignant tumors can spread (metastasize) through invasion, infiltration of surrounding tissues, lymph, and/or blood vessels.
• Markers and enzymes are used to identify cells. Tumor cell markers are antigens expressed on the tumor surface. Examples given include hormones, alpha-fetoprotein, and isozymes.
• Apoptosis is programmed cell death; its mechanisms are categorized as extrinsic and intrinsic pathways. These occur under physiologic (normal) or pathologic (disease) conditions.