Pathology and Pathophysiology: Mechanisms of Disease
Pathology and pathophysiology questions ask why a disease produces its signs. Understand cellular injury, inflammation, neoplasia, hemodynamics, and the organ-specific mechanisms behind common syndromes.
Concepts to master
- Cell injury and death: reversible vs. irreversible, necrosis vs. apoptosis, and free-radical injury.
- Inflammation: acute vs. chronic, granulomas, and the role of cytokines.
- Neoplasia: benign vs. malignant, grading vs. staging, tumor markers, and metastasis routes.
- Hemodynamics: thrombosis, embolism, infarction, and edema mechanisms.
- Organ pathophysiology: heart failure, renal failure, liver disease, and respiratory failure.
Traps
Questions often confuse morphology with mechanism or grading with staging. Another trap is assuming a tumor marker is diagnostic when it is only supportive. Be careful with edema: distinguish hydrostatic, oncotic, lymphatic, and inflammatory causes. Watch for questions that ask for the earliest or most specific change rather than the most dramatic one.
Worked rule of thumb
For any edema or effusion, ask which Starling force is altered. For any mass, separate grade (differentiation) from stage (spread). For any cell injury, ask whether the insult is reversible (ATP restored) or irreversible (membrane integrity lost). These three questions resolve most pathophysiology stems.