Mechanisms of Disease – Condensed Notes (Lessons 1.1–1.3)

Pathology: traits, causes, and effects of abnormal conditions, causing measurable changes in structure and function
Homeostasis: internal stability of the body maintained by many organs/structures working together
Signs vs Symptoms: Signs = objective findings; Symptoms = subjective experiences
Syndrome: defined collection of signs and symptoms that characterize a disorder
Pathogenesis: stages of development of a disease
Acute illness: abrupt onset of symptoms with a brief course
Chronic illness: develops slowly, may be intermittent; lasts longer than $6$ months

Acute inflammation: normal protective physiologic response to tissue injury/disease
Classic signs: redness, heat, swelling, pain, loss of function
Intensity depends on cause, location, and patient condition
Purpose: wall off/destroy/digest bacteria and dead/foreign tissue; prevent spread via antibodies and cellular chemicals
Repair after insult is contained
Chronic or excessive inflammation can cause tissue damage

Infection caused by pathogens
Signs: redness/swelling, heat, pain, fever, pus, enlarged lymph glands
Symptoms: fever, headache, body aches, fatigue, loss of appetite
Sources: endogenous (inside body) vs exogenous (outside body)
Modes of transmission: direct/indirect contact, inhalation, ingestion, inoculation by insects/animals
Prevention: natural barriers, inflammatory and immune responses, isolate/identify organism, treatment, vaccination programs, disease reporting
Superbugs: virulent antibiotic-resistant strains (e.g., MRSA, VRE, CRE); hygiene reduces spread

Benign neoplasms: develop slowly, arise from any tissue, resemble tissue of origin, rarely recur after removal
Malignant neoplasms: cells vary in appearance, disordered, invade other tissues, metastasis complicates eradication
Genetic diseases: humans have 23 chromosome pairs; sex chromosomes XX/XY; genotype; karyotype; genes; mutations
Causes of genetic diseases: single-gene abnormalities, polygenic diseases, chromosomal aneuploidy, chromosomal structure alterations, mutations
Modes of inheritance: Autosomal dominant; Autosomal recessive; X-linked (sex-linked) recessive
Genetic counseling: communication about risk, diagnosis, course, and options; testing discussed; counselors available at major centers

Cancer: group of diseases with uncontrolled cell proliferation; neoplasms that disrupt healthy tissue
Tumor characterization: malignant or benign; cell type and tissue of origin
Prevention guidelines: diet rich in fruits/vegetables/whole grains; avoid active/passive tobacco smoke; limit sun exposure; limit alcohol; avoid carcinogenic exposures; maintain healthy weight; HPV vaccination
Screening: tumor markers (blood serum elevations) help diagnosis, monitor therapy response, and detect recurrence
Stages (TNM) of cancer: $T$ = primary tumor size/extent; $N$ = regional lymph node involvement; $M$ = distant metastases
Stage I is best prognosis; Stage $IV$ is most advanced; prognosis also affected by age, serum markers, and time to treatment
Grading: tumor differentiation (pathologic grade) complements stage information
Treatments: Surgery, Palliative surgery, Chemotherapy (cycles with rest periods), Hormone therapy, Immunotherapy
Consequences of therapy: toxicity to body, risk of secondary cancers, notable effects in children (growth/cognitive impact); advances include stereotactic radiosurgery (SRS)
Cancer vaccines: research to stimulate immune response against cancer cells

Hospice care: compassionate, patient-centered; focuses on comfort, dignity, and family support; does not hasten or postpone death; provided in various settings
Immune disorders: hypersensitivity (allergy), autoimmune diseases, immunodeficiency
Hypersensitivity: allergen exposure triggers IgE response; histamine release; range from mild to life-threatening
Autoimmune diseases: antibodies against self-antigens; triggers unknown
Immunodeficiency: reduced/absent immune response; causes can be primary or secondary
Diagnosis of disease: history, physical examination, diagnostic studies (labs, microscopy, imaging)
Pain: physiology involves nociceptors; pain is subjective and can be physiologic or psychological; classify and measure pain for management
Pain relief: acute pain often treated with opioids; chronic pain treated with NSAIDs, antidepressants, anticonvulsants; adjuncts include physical therapy and massage
Holistic and Integrative Medicine: focus on whole person; integrates conventional medicine with CAM; evidence-based approach
Cultural diversity: appreciate language, beliefs, health views; providers should overcome barriers; learn about different cultures
Gene therapy and Stem cell research: gene therapy uses vectors to modify gene expression; ex vivo vs in vivo approaches; aims to treat autosomal/X-linked recessive diseases by adding functional genes; stem cells used in regenerative medicine and transplants

Pain physiology and classification: acute vs chronic; transient vs intractable; assessment often accompanies vitals
Pain measurement scales: used to quantify pain
Patient teaching: patient-centered, active listening, assess understanding, plan with patient input; ensure legal responsibilities are clear
Goals of patient teaching: improve treatment compliance, support, and healthy lifestyle choices; build trust
Reasons for teaching: reduce anxiety, answer questions, improve coping, practice care skills, reduce clinic visits/hospitalizations

Preoperative care: clarify expectations, review instructions, arrange necessary tests
Postoperative care: reassure about pain control, explain warning signs, provide written instructions and contact info, connect to support resources
Special considerations: cancer or life-threatening disease require personalized support, clear instructions, feedback, caregiver support, and referrals

Diagnosis relies on medical history, physical examination, and diagnostic tests (cell/tissue analysis and chemical assays)
Preventive health care aims to identify risk factors and apply screening/tests; patient education is essential
Preventive health measures include lifestyle choices and vaccination as appropriate
Integrative medicine combines conventional and CAM therapies supported by evidence