wound healing

Question 1

what is a wound

Answer 1

loss of integrity of skin tissue

Question 2

what causes chronic wounds (2)

Answer 2

1. disruption in normal healing process;
2. slowed/incomplete healing

Question 3

3 phases of wound healing (post fibrin plug formation)

Answer 3

1. inflammatory phase (0-48hrs);
2. proliferative phase;
3. maturation and remodelling phase (3+ weeks)
   all over lapping, not clearly separated from each other

Question 4

clinical signs of the inflammatory phase (4)

Answer 4

rubor, tumor, dolour, calor

Question 5

3 main steps in the inflammatory phase

Answer 5

1. wound cleaning (phagocytosis - monocytes, macrophages, lymphocytes);
2. chemo-attraction (growth factors, cytokines, fibroblasts/immune cells);
3. structural framework development (temporary matrix)

Question 6

3 main stages of the proliferative phase

Answer 6

1. net collagen synthesis (GFs, ECM molecules etc.);
2. increased wound tensile strength (epidermal cells proliferate and move to wound edge/granulation tissue, mylofibroblasts generate force to contract and close wound);
3. scar formation (apop of immune cells, fibroblasts etc.; remaining fibroblasts lay down collagen)

Question 7

what happens in the maturation/remodelling phase

Answer 7

reorganisation of collagen - Type 1 and 3

Question 8

2 types of wound healing

Answer 8

primary intention; secondary intention

Question 9

6 things that can affect wound healing

Answer 9

1. size of wound;
2. blood supply to area;
3. presence of foreign bodies or microorganisms;
4. age/health of a pt;
5. nurtitional status;
6. drugs (e.g. steroids)

Question 10

primary intention vs secondary intention

Answer 10

primary - e.g. surgical incision; immediate closure of wound edges when no loss of tissue has occured -> rapid epithelial coverm faster healing, better cosmetic result;
secondary - e.g. trauma; spontaneous healing of wound without direct closure -> granulation, slow epithelial cover, wound contraction, compromised cosmetic result

Question 11

2 types of wound healing

Answer 11

primary intention; secondary intention

Question 12

primary intention healing pathway (4)`

Answer 12

1. wound edges joined by fibrin plug;
2. regrowth of basal layer of epidermis;
3. lysis of fibrin and re-epithelialisation;
4. restoration to intact skin

Question 13

secondary intention healing pathway (4)

Answer 13

1. large defect filled by fibrin clot;
2. new blood vessels and fibroblasts (granulation tissue) grow from the dermis into fibrin;
3. collagen laid down by granulation tissue fibroblasts to restore integrity;
4. maturation of collagen achieves structural integrity and allows regrowth of epidermis

Question 14

what is tertiary intention healing

Answer 14

healing after traumatic injury, dirty surgery, delayed primary intention etc. -> initially left open after removal of all non-viable tissue, wound edges brought together after a few days when it appears clean and well vascularised

Question 15

examples of treatments for skin lesions (8)

Answer 15

1. cryotherapy;
2. creams/ointments;
3. photodynamic treatment;
4. curretage
5. shave excision
6. excision
7. RT
8. chemo

Question 16

how does cryotherapy cauuse cell death (4)

Answer 16

1. ice crystal formation;
2. osmotic differences -> cell disruption;
3. ishaemic damage
4. immunological stimulation

Question 17

what is usually used for cryotherapy

Answer 17

liquid nitrogen

Question 18

4 contraindications for cryotherapy

Answer 18

1. pigmented lesions;
2. malignant lesions (needs histology);
3. cold urticaria;
4. lesion of uncertain diagnosis

Question 19

what is 5-flurouracil cream and when is it used

Answer 19

an anti-metabolite that inhibits pyrimidine metabolism and DNA synthesis; used for multiple AKs (too many for cryo), BCCs, Bowen’s disease

Question 20

what condition is cryotherapy most commonly used for

Answer 20

actinic keratosis

Question 21

what is aldara (imiquimod 5%) and when is it used

Answer 21

an iminazoquinolone that acts as an immune response modulator -> stimulates release of cytokines;

used for genital warts, superficial basal cell carcinoma, and actinic keratosis

Question 22

what is photodynamic therapy

Answer 22

the activation of topical porphyrin cream (psorelin) to destroy cancer/pre-cancer -> scale removed, cream applied and then light shone onto sensitised area

Question 23

3 contraindications for photodynamic therapy

Answer 23

1. pigmented lesions;
2. non-histologically sampled malignant lesions;
3. patients unable to tolerate pain

Question 24

what is curretage/cautery and when is it used

Answer 24

lesion is scraped off and heat is applied to skin surface;
used for pyogenic granuloma, cutaneous horn (AK), seborrhoeic wart, small nodular BCCs

Question 25

5 contraindications of cutterage/cautery

Answer 25

1. pigmented lesions; 2. BCCs (morphoeic, infiltrating, ill-defined) 3. poor cosmetic result (vermillion boarder, nose tip, chin); 4. BCC on site w high recurrence rate (nose, eye, scalp etc.); 5. SCCs (most of them)

Question 26

what is a shave excision

Answer 26

lesion is shaved off and heat applied to skin

Question 27

2 indications for shave excision

Answer 27

usually benign lesions 1. chrondrodermatitis nodularis helicis - painful nodule which develops on ear due to side sleeping; 2. benign naevi;

Question 28

2 contraindications for shave excision

Answer 28

1. keratoacanthoma; 2. melanomas!

Question 29

what is an excision

Answer 29

removal of lesion with adequate margin

Question 30

4 contraindications to excision biopsy

Answer 30

1. no valid consent; 2. INR too high; 3. underpreparation with antplatelets/anticoagulatns; 4. pacemaker check

Question 31

indications for excision biopsy (2)

Answer 31

1. suspected tumours; 2. pigments lesiosn

Question 32

5 factors to consider when determining suitability for RT

Answer 32

1. type of lesion (is it radiosensitive e.g. BCC, SCC etc; whats the morphology e.g. nodular); 2. site (areas where surgery may be difficult); 3. previous radiotherapy; 4. suitability of other treatments 5. patient's preference

Question 33

what is micrographic surgery

Answer 33

excision of horizontal sections cut from the periphery of an excision specimin -> microscope needed

Question 34

why is micrographic surgery used

Answer 34

to maximise the confidence of tumour clearance with minimal loss of surrounding normal tissue -> time consuming and expensive tho

Question 35

when might Moh's surgery (micrographic) be indicated

Answer 35

for tumours that are recurrent, in high risk zones and have agressive growth

Question 36

what lesions are biopsies not done in

Answer 36

pigmented lesions - the area biopsied may not be a true representation of the whole cancer

Question 37

when is chemo indicated (derm -4)

Answer 37

metastatic malignant melanoma; localised advanced mealomas (isolated limb perfusion); SCCs; rare BCCs

Question 38

what targeted therapies are available for cancers (3)

Answer 38

1. BRAF inhibitors 2. MEK inhibitors 3. C-KIT

Question 39

adjuvant vs neo-adjuvant therapy

Answer 39

adjuvant - used after primary procedure to help reduced the recurrance of the tumour neo adjuvant - used to reduce the size of the tumour prior to the primary tumour

Question 40

example of adjuvant therapy

Answer 40

IF-alpha