exam 3 diseases Flashcards
Albinism
absence of tyrosinase
Vitiligo or leukoderma
loss of
pigment, resulting in irregular pale patches of skin
Merkel Cell Carcinoma (MCC)
Small, asymptomatic, ulcerated, cystic lesion
Incidence increase significant because of better diagnostic tools & aging
population
Contour lines
Contours of 1st and 5th metatarsals Peroneal tendons Achilles tendon Heel
Wounds remain chronic for various reasons
Vascular insufficiency Diabetes mellitus Compromised nutrition Compromised immunologic status Advanced age Infection Fibroblasts become prematurely senescent Dysregulation of matrix metalloproteinases Mechanical stres
iofilm
bacteria growing in an extracellular matrix. Biofilms are generally composed of varied species of
bacteria, fungi, yeasts, algae and other microbes, in addition to cellular debris. They can be monospecies or polymicrobial. The
ones in wounds tend to be polymicrobial. The bacteria first attach to one another, then when the numbers present are high
enough (as sensed by quorum sensing mechanisms), the bacteria secrete polysaccharides, N-acetylglucosamine or proteins.
The production of these molecules help the biofilm to form a complex, three-dimensional structure within a few hours. These
structures can also get detached as clumps of cells which move and may attach to another surface and propagate further.
Examples of Chronic Wounds
venous leg ulcer diabetic foot ulcer arterial ulcer pressure sore hypertrophic scar keloid
Coagulation and Haemostasis phase
The coagulation/clotting cascade is activated platelet aggregation and
clot formation.
Inflammatory Phase
establishes an immune barrier against invading micro-
organisms
Proliferative Phase
Fibroblast migration:
•Starts on third day after injury, last for ~2 weeks
•Fibroblast migration and deposition of newly synthesized ECM
Remodelling Phase
Development of a new epithelium and final scar formation
Lasts 1-2 years or longer
• Delicate balance of degradation (metalloproteinases) and synthesis of ECM
• Collagen bundles increase in diameter, hyaluronic acid and fibronectin are
degraded
Primary intension
healing of a clean wound without loss of tissue and
uninfected surgical incisions approximated by sutures.
Secondary intention
healing takes a lot longer because of large tissue
losses and formation of large amounts of granulation tissue to fill the
wound.
Dark granulation tissue can be indicative of
poor perfusion,
ischemia and / or infection.
Tertiary intention
Delayed closure of wound Example: perform an I&D and close at a later date to allow for adequate debridement and granulation tissue formation
