Medical Examination Techniques

Diagnostic Examinations

• Gross examination reveals visible alterations (lesions) through physical examination or autopsy.
• Histologic examination allows alterations to be identified via microscopy.
• Laboratory examinations include blood tests, urine samples, and DNA tests.
• Specialized examinations include X-rays, ultrasound, endoscopy, and magnetic resonance imaging (MRI).

Cardinal Signs of Inflammation

• Celsus identified four cardinal signs of acute inflammation:
  • Calor (heat)
  • Dolor (pain)
  • Rubor (redness)
  • Tumor (swelling)
• Galen later introduced a fifth sign: functio laesa (impaired function).

Phases of Acute Inflammation

• Phase I (0-4 hours): Presence of preformed factors including antibodies, complement, and vasoactive factors (e.g., CS: RUBOR, CALOR).
• Phase II (4-48 hours): Influx of neutrophils leads to redness, heat, pain, and swelling (CS: RUBOR, CALOR, DOLOR, TUMOR).
• Phase III (24-96 hours): Macrophages enter, enhancing signs of inflammation (CS: RUBOR, CALOR, DOLOR, TUMOR, FUNCTIO LAESA).
• Phase IV includes specialized electrical activity measurements in diagnostics.

Electrical Activity Diagnostics

• Electrocardiogram (ECG/EKG): Measures heart's electrical activity including P wave (atrial depolarization), QRS complex (ventricular depolarization), and T wave (ventricular repolarization).
• Electroencephalogram (EEG): Monitors brain electrical activity.
• Electromyogram (EMG): Assesses muscle electrical activity relevant to conditions like ALS, MS, and myasthenia gravis.

Tissue Responses to Stress

• Hypertrophy: Increase in cell/organ size due to increased demand.
• Hyperplasia: Increased number of cells in dividing tissues.
• Atrophy: Shrinkage of cells/organ size resulting from decreased demand.
• Metaplasia: Transformation of one cell type to another adapted to environmental changes.

Types of Atrophy

• Physiologic atrophy (e.g., shrinkage of the uterus post-pregnancy) is linked to hormonal changes.
• Pathologic atrophy occurs from inactivity, loss of innervation, insufficient blood supply, malnutrition, and aging.

Histological Overview of Epithelial Cells

• Epithelial cells line most body surfaces, categorized as:
  • Simple squamous epithelium: Lines cavities and vessels.
  • Cuboidal epithelium: Found in nephrons and thyroid glands.
  • Columnar epithelium: Lines gastrointestinal tract and respiratory tract.

Metaplasia Types

• Squamous metaplasia occurs in smokers' upper airways.
• Intestinal metaplasia, such as Barrett’s esophagus, results from chronic gastroesophageal reflux disease (GERD).

Wound Healing Impairments

• Local factors affecting healing include poor perfusion, infection, foreign bodies, and mechanical stress.
• Systemic factors include age, diabetes, malnutrition, certain medications, and genetic disorders.
• Incomplete healing can result in dehiscence or ulceration, while excessive healing may cause hypertrophic scars or keloids.

Inflammation Overview

• Inflammation serves as a protective mechanism against pathogens or tissue damage.
• It involves vascular and cellular components, showing variations based on tissue types.
• Key events in inflammation include alerting the body, containing the threat, destruction of harmful agents, and setting the stage for repair.

Inflammatory Trigger Events

• Triggers include infections, traumas (mechanical, thermal), chemical exposure, foreign bodies, tissue necrosis, and immune reactions.
• Blood vessels, inflammatory cells, vasoactive factors, complement systems, and blood clotting mechanisms all play crucial roles in inflammation.

Sequence of Inflammation Events

• Microbes breach the skin, triggering antibody binding and complement activation.
• Complement factors C3a and C5a recruit mast cells, leading to the release of vasoactive factors (histamine and bradykinin) that enhance blood flow and attract immune cells.
• Neutrophils are the first responders, followed by macrophages, which activate further defense mechanisms, such as fever and acute phase proteins.