Overview
This lecture covers essential concepts in pathophysiology, focusing on hematology, immunology, fluid and electrolyte balance, acid-base disorders, cardiovascular and respiratory diseases, and relevant clinical interventions.
Hematology & Oncology
- Thrombocytopenia from leukemia is managed with activity restriction.
- Myeloma often leads to renal insufficiency.
- Acute lymphoid leukemia (ALL) has the best prognosis for long-term survival.
- Proto-oncogenes promote cellular growth; P53 is a common tumor-suppressor gene defect.
- Iron deficiency is the most common cause of anemia; aplastic anemia shows pancytopenia.
- Hemophilia B (Christmas disease) is a clotting disorder.
- Chemotherapy targets rapidly dividing cells post–tumor removal.
- Philadelphia chromosome translocation forms the bcr-abl gene in leukemia.
Immunology & Hypersensitivity
- Type IV hypersensitivity does not involve antibody production; type I is mediated by IgE and histamine.
- Selective IgA is the most common B cell immune deficiency.
- Anaphylactic shock is frequently caused by antibiotics, showing massive histamine release and hypotension.
- HIV/AIDS is a primary immunodeficiency disease.
- RhoGAM is used for Rh-negative women carrying Rh-positive fetuses.
Acid-Base & Electrolyte Disorders
- Respiratory acidosis: caused by hypoventilation; respiratory alkalosis: caused by hyperventilation.
- Starvation ketoacidosis presents with rapid breathing, lethargy, and abdominal pain.
- Metabolic acidosis risk: prolonged diarrhea; metabolic alkalosis from vomiting/suctioning.
- Hypernatremia in tube-fed elderly is due to inadequate water intake.
- Sodium imbalances affect cellular fluid shifts; elderly adults have decreased TBW.
Cardiovascular & Respiratory Disorders
- Disseminated intravascular coagulation (DIC) follows massive trauma or septic shock.
- Orthostatic hypotension: significant BP drop and HR increase on sitting/standing.
- Class II shock: blood loss with orthostatic symptoms but normal supine BP.
- Cardiogenic shock defined by reduced cardiac output; pulmonary edema causes pink frothy sputum.
- Flail chest: paradoxical chest wall movement.
- COPD type A: normal PaCO2, barrel chest, minimal sputum; type B: more sputum.
- Bronchiectasis: foul sputum, associated with cystic fibrosis.
- Chronic bronchitis leads to cor pulmonale.
- Asthma: allergen exposure → inflammation, edema, bronchoconstriction.
- Tuberculosis: caused by Mycobacterium tuberculosis, Ghon tubercles on x-ray.
Fluid Balance & Renal
- Infants have more extracellular than intracellular fluid.
- Salty broth is preferable to water for rehydration in dehydration.
- Increased preload causes edema.
- Hypovolemia is best managed with crystalloids.
Coagulation & Blood Disorders
- von Willebrand factor deficiency impairs platelet adhesion.
- Vitamin K deficiency: normal platelets/bleeding time but prolonged PT/INR.
- DIC: abnormal clotting in microvasculature.
- Deep vein thrombosis risk: pulmonary embolus.
- Heparin is used to prevent more clots in DVT.
Key Terms & Definitions
- Thrombocytopenia — low platelet count, risk of bleeding.
- Proto-oncogene — normal gene that can become cancerous when mutated.
- Dysplasia — abnormal cell growth, considered preneoplastic.
- Allostasis — adaptive processes to maintain stability.
- Orthostatic hypotension — BP drop upon standing.
- Disseminated Intravascular Coagulation (DIC) — widespread microvascular clotting and bleeding.
- Metabolic acidosis — low blood pH due to acid accumulation or bicarbonate loss.
- Cardiogenic shock — inadequate tissue perfusion due to heart failure.
- Anaphylactic shock — severe allergic reaction with systemic vasodilation.
- Hyponatremia/Hypernatremia — low/high sodium levels in blood.
Action Items / Next Steps
- Review mechanisms, symptoms, and management of shock types.
- Study major causes and laboratory findings of common anemias.
- Memorize key features distinguishing respiratory disorders like COPD, asthma, and bronchiectasis.
- Practice blood pressure interpretation according to JNC-7 criteria.