Comprehensive Notes on General Pathology and Disease Mechanisms of Disease

Disease Progression and Stages

• Latenzstadium (Latency Stage): This is the initial phase where the organism is first confronted with a cause of illness and begins the internal process of dealing with it. At this stage, the patient is symptomless and no diagnosis is possible.
• Inkubationszeit (Incubation Period): Specific to infectious diseases, this corresponds to the latency period.
• Prodromalstadium (Prodromal Stage): This stage is marked by the appearance of the first warning signs or nonspecific symptoms, such as malaise (Unwohlsein) or fever. A diagnosis may start to become possible here.
• Manifestationstadium (Manifestation Stage): The disease becomes fully manifest with specific symptoms typical to the condition. Examples provided include skin rashes, severe sore throat, and coated tonsils.
• Rekonvaleszenzstadium (Recuperation/Convalescence Stage): The final phase where the organism attempts to return to its original healthy state. This stage marks the end of the active disease process.

Outcomes and Forms of Recovery

• Restitutio ad integnium (Complete Recovery): The full restoration to an uninjured, healthy state.
• Defektheilung (Incomplete Recovery): The disease is cured, but a permanent residual defect remains, such as a scar (Narbe).
• Chronifizierung (Chronification): The illness does not heal and transitions into a lifelong course. Examples include Diabetes and Multiple Sclerosis (MS).
• Rezidivierung (Recurrence): The disease appears to heal initially but returns after a short period.

Definitions and Stages of Death

• Klinischer Tod (Clinical Death):
  • Characterized by the cessation of cardiovascular function (Herzkreislauffunktion) and respiration (Atmung), as well as unconsciousness.
  • This stage is reversible through successful resuscitation (Reanimation).
• Hirntod (Brain Death):
  • Characterized by the cessation of brain function.
  • This marks organ death or individual death and is not reversible.
  • If resuscitation is unsuccessful, brain death is confirmed, which may lead to potential organ donation and transplantation.
• Biologischer Tod (Biological Death):
  • Every organ and cellular function has ceased.
  • Confirmed by definitive signs of death (Sichere Todeszeichen).

Anamnesis (Medical History Taking)

1. Jetzt Anamnese (Current Anamnesis): Focuses on the patient's current condition.
2. Eigenanamnese (Personal History): Covers any previous illnesses, medical history, known chronic diseases, current medications, and allergies.
3. Familienanamnese (Family History): Investigates direct hereditary diseases and illnesses that occur frequently within the family.
4. Sozialanamnese (Social History): Examines the professional and social environment, including occupation, whether the patient lives alone, and their relationship with relatives.
5. Sonderform: Fremdanamnese (Special Form: Third-Party History): Used when the patient is unable to provide information themselves. This typically applies to cases of psychiatric illness, children, dementia, intellectual disability, coma, or speech disorders.

Diagnostic Methods

• Clinical Examination:
  • Inspektion: Visual inspection.
  • Palpation: Touching or feeling the body.
  • Auskultation: Listening to sounds within the body.
  • Perkussion: Tapping on parts of the body.
• Laboratory Investigations:
  • Chemical composition of body fluids.
  • Genetic composition.
  • Antibody testing.
• Functional Tests:
  • Blood pressure measurement.
  • Vision and hearing tests.
  • Joint mobility assessments.
• Imaging Procedures:
  • Röntgen (X-ray).
  • CT (Computed Tomography).
  • MRT (Magnetic Resonance Imaging).
  • Ultraschall/Sonografie (Ultrasound).
  • Szintigrafie (Scintigraphy).
  • Endoskopie/Spiegelung (Endoscopy).

Classification of Symptoms

Symptoms are the signs of illness resulting from anamnesis and diagnostics. They are divided into several categories:

• Specific Symptoms: These can be clearly assigned to one or two specific diseases (e.g., typical skin rashes or specific pain locations).
• Unspecific Symptoms: These occur across a wide variety of illnesses (e.g., fever, headache, fatigue).
• Objective Symptoms: These can be determined and verified by external observers (e.g., fractures, fever, redness of the skin, diarrhea, vomiting).
• Subjective Symptoms: These are perceived and reported only by the patient (e.g., dizziness/Schwindel, shortness of breath/Atemnot, numbness/Taubheit, headache).

Therapy and Medical Intervention

• Types of Therapy:
  • Symptomatisch (Symptomatic): Treats the symptoms (e.g., painkillers).
  • Kausal (Causal): Treats the underlying cause of the disease (e.g., antibiotics for bacteria).
  • Kurativ (Curative): Aimed at full healing.
  • Palliativ (Palliative): Aimed at making the remaining time as pleasant as possible when a cure is no longer possible.
  • Konservativ (Conservative): Treatment without opening the body (e.g., a cast/Gips for a fracture).
  • Operative: Treatment involving surgery or opening the body (e.g., screws for a fracture).
• Examples of Combined Procedures:
  • Depression: Treated via Antidepressants or Psychotherapy.
  • Mamakarzinom (Breast Cancer): Treated via Chemotherapy for healing (Curative) or Operative means.
• Methodologies: Includes medication, occupational therapy (Ergotherapie), speech therapy (Logopädie), physiotherapy, radiation therapy (Strahlentherapie), and psychotherapy.
• Alternative Procedures: Homeopathy.

Prophylaxis (Prevention)

• Primärprophylaxe: Intended to prevent the initial occurrence of a disease.
• Sekundärprophylaxe: Intended to prevent the recurrence of a disease.
• Preventative Measures: Medications, healthy diet, movement/exercise, general hygiene, sleep, vaccination, and appropriate clothing.

Immunization

• Active Immunization:
  • Uses weakened or killed pathogens (antigens).
  • The organism actively builds antibodies and memory cells (Gedächtniszellen).
  • Provides long-term or lifelong protection.
  • Takes several weeks to build full protection.
  • Potential side effects: mild disease symptoms or allergic reactions.
  • Examples: FSME, Hepatitis A and B, Influenza.
• Passive Immunization:
  • Organically produced antibodies against the disease are administered directly.
  • Effective immediately and can be administered during the incubation period.
  • Provides protection only for a few weeks because no memory cells are formed.
  • Allergic reactions occur rarely.
  • Examples: Tetanus, Tollwut (Rabies).

External Disease Causes

• Inanimate (Unbelebte) Causes:
  • Radiation (Strahlung).
  • Chemical substances.
  • Thermal damage (Thermische Schädigung).
  • Mechanical damage (Mechanische Schäden).
• Animate (Belebte) Pathogens:
  • Viruses: Size in nanometers, visible only via electron microscope. Composed of DNA or RNA with a protein shell. Occur only in living cells (wirt-dependent) and have no independent metabolism. Treated with Virostatics and symptomatic therapy. Examples: Herpes, Hepatitis, Corona, Grippe (Flu).
  • Bacteria: Size in micrometers. Prokaryotic (no enclosed nucleus). Occur intra- and extracellularly, even on inanimate surfaces. Some are anaerobic. Categorized as Bacilli/Stäbchen (e.g., Tuberculosis, Tetanus), Spirals/Spirillen (e.g., Syphilis, Cholera, Salmonellen). Treated with Antibiotics.
  • Fungi (Pilze): Occur intra- and extracellularly, on or in the body. Often affect immunocompromised patients or follow antibiotic use. Treated with Antimycotics. Examples: Foot fungus, vaginal fungus, Soor (thrush).
  • Parasites: Live at the expense of the host. Visible to the naked eye.
  • Ectoparasites: On the body surface (Mites, Ticks, Lice).
  • Endoparasites: Inside the body (Worms).
  • Treated with Anthelmintics.

Virulence and Inflammation

• Virulenz: Describes the totality of the pathogenic properties of a pathogen.
  • Infektiosität: Ability to enter the organ and multiply despite natural defenses.
  • Toxizität: Poisonous effect of germs and toxins.
  • Vitality: Survival capability of the germs.
• Chronology of Inflammation:
  1. Alteration: Tissue damage causing the release of mediators (Histamine, Bradykinin, Serotonin). These cause vasodilation (widening of small vessels) and increased permeability.
  2. Hyperämie: Increased blood flow to the inflamed area.
  3. Exsudation: Blood fluid enters the tissue, creating local edema.
  4. Emigration and Phagocytosis: Leukocytes migrate to the inflammation site to act as scavengers (phagocytes), removing cell debris, bacteria, and dead tissue. Bacterial inflammation results in the formation of pus (Eiter).
  5. Proliferation: In cases of severe inflammation with large tissue defects, new capillaries and fibroblasts migrate in to build Granulationsgewebe (a vessel-rich, spongy transition tissue).
  6. Narbenbildung (Scarring): Vessels and cells recede, leaving behind collagen fibers that form scar tissue (Defektheilung).

Cardinal Symptoms and Systemic Reaction

• Cardinal Symptoms of Inflammation:
  • Rubor: Redness (due to vasodilation).
  • Calor: Heat (due to vasodilation).
  • Tumor: Swelling (due to local edema and increased permeability).
  • Dolor: Pain (due to pressure from edema on receptors and effects of mediators).
  • Functio laesa: Impaired function (due to pain and swelling).
• Fever:
  • Body temperature increases to accelerate defenses.
  • From $38,5\,^{\circ}\text{C}$, it aids in killing germs.
  • Above $41,0\,^{\circ}\text{C}$, internal proteins denature, which is fatal.
  • Treated with Antipyretics (Antipyretika).
• Leukocytes + CRP Value: Elevated levels are signs of an activated immune response in the body.

Classification of Inflammation

• Akut (Acute): Rapid onset and short duration (e.g., acute appendicitis).
• Chronisch (Chronic):
  • Primary Chronic: Insidious (schleichend) onset, lifelong duration (e.g., Polyarthritis).
  • Secondary Chronic: Emerges from an acute inflammation if the cause is not eliminated (e.g., chronic bronchitis).

Specialized Inflammatory Terms

• Abszess: An encapsulated collection of pus in the tissue.
• Furunkel: A deep, painful abscess of a hair follicle.
• Empyem: A collection of pus in a pre-existing body cavity.
• Phlegmone: A diffuse, spreading purulent inflammation in the tissue.

Local Circulatory Disorders and Thrombosis

Thrombosis is driven by three main factors:

1. Changed blood flow (Stase): Slowed or disturbed flow, caused by immobility (bedridden, casts) or long periods of sitting during travel.
2. Change in the vessel wall: Damage to the inner lining (endothelium) caused by injuries, operations, or inflammation. The vessel becomes "rough," activating coagulation.
3. Change in blood composition (Hyperkoagulabilität): Increased clotting tendency due to genetics, pregnancy, or certain medications.

• Thrombosis Prophylaxis: Movement, avoiding long periods of sitting/standing, reducing animal fats, drinking plenty of fluids, not smoking, avoiding the contraceptive pill, and using support stockings (Stützstrümpfe).

Embolism and Infarction

• Embolie: The sudden blockage of a blood vessel by material (embolus) carried by the bloodstream.
• Types of Embolism:
  1. Fester Embolus (Solid): Most common. A blood clot (thrombus) forms, often in deep leg veins, detaches, and is trapped elsewhere, such as the lungs (Lungenembolie).
  2. Fettembolie (Liquid): Fat droplets enter the bloodstream, often after fractures of long bones (e.g., Femur) or orthopedic surgery.
  3. Luftembolie (Gas): Air enters the bloodstream via large vein injuries or medical procedures. Rarely, it occurs in diving accidents (decompression sickness).
• Infarkt: A necrotic area of tissue caused by sudden oxygen and nutrient deprivation due to vessel blockage.
  • Ischämischer Infarkt: Result of complete arterial blockage (e.g., heart attack due to coronary artery closure).
  • Hämorrhagischer Infarkt: Blockage combined with an influx of blood from surrounding vessels into the necrotic tissue (e.g., lung infarct after pulmonary embolism).

Cellular Adaptations: Growth and Reduction

• Hypertrophie: Enlargement of cells causing the entire organ to grow. Cell count remains constant (e.g., cardiac muscle hypertrophy).
• Hyperplasie: Increased number of cells causing the tissue/organ to grow (e.g., bone marrow hyperplasia).
• Atrophy:
  • Einfache Atrophie: Tissue shrinks because cells shrink; cell count remains constant. Occurs due to disuse or aging (e.g., muscle atrophy after a cast or Osteoporosis).
  • Druckatrophie: Result of permanent pressure leading to poor blood flow (e.g., Dekubitus/Pressure ulcer).
• Hypoplasie: A developmental condition where an organ or tissue is smaller from the beginning because there are too few cells (e.g., Zahnhypoplasie).

Cell Death: Apoptosis and Necrosis

• Apoptose: Planned, programmed, and orderly cell death controlled genetically.
• Nekrose: Uncontrolled, pathological cell death caused by external damage (hypoxia, infection, toxins).
  • Macroscopic signs: Tissue discoloration (Gewebsverfärbung), consistency change, and demarcation.
  • Gerinnungsnekrose (Coagulation): Proteins clot; tissue remains firm and dry initially. Caused by sudden ischemia (e.g., heart attack).
  • Verflüssigungsnekrose (Liquefaction): Enzymes liquefy the tissue into a mushy or liquid mass. Typical in water-rich or nervous tissue (e.g., brain infarct).
  • Consequences: Inflammation, loss of function, abscesses, scars, or sepsis.

Mechanisms of Edema

1. Increased Hydrostatic Pressure: Fluid is pressed out of the blood vessel into the tissue. Example: Heart failure leading to leg edema.
2. Reduced Colloid Osmotic Pressure: Occurs when there is too little protein (especially Albumin) in the blood, so fluid cannot be held in the vessel. Example: Liver cirrhosis or malnutrition (Ascites/Bauchwasser).
3. Increased Capillary Permeability: Vessel walls become "leaky," allowing fluid and proteins to exit. Example: Inflammation or allergic reactions (e.g., swelling after an insect bite).

Questions & Discussion

• What is a Differential Diagnosis? It is the process of distinguishing between several possible diseases that cause similar symptoms to find the correct diagnosis. The mnemonic is: "Similar symptoms - but only one right diagnosis." The goals are to avoid wrong treatments, select the correct therapy, and gain diagnostic certainty.
• Why is an immobilized patient particularly at risk for thrombosis? Without movement, blood flows more slowly and the "muscle pump" functions poorly. These are ideal conditions for blood to clot more easily and form a thrombus.
• What medications act against specific conditions?
  • Antipyretika (Antipyretics): Combat fever (Symptomatic).
  • Analgetika (Analgesics): Combat pain (Symptomatic).
  • Antiphlogistika: Combat inflammation (Symptomatic).
  • Antibiotika: Combat bacteria (Causal).