Dermatology Flashcards
What does MRSI stand for and what is the mechanism of resistance for MRSI?
Methicillin resistant staphylococcus infections
Resistant by bacterial acquisition of the mecA gene which encoded a penicillin-binding protein (PBP2a). has much lower binding affinity for beta-lactams
What could these clinical signs be indicative of, skin abscess, otitis externa, wounds, pyoderma (papules, erosions, crusts, exudates?
superficial methicillin -resistant pyoderma, demodicosis, Malassezia, cutaneous drug eruption, vasculitis, pemphigus foliaceus
give 3 risk factors for MRSI
Suspect if px with non-healing wound, folliculitis or abscess present after completing ab tx, esp beta-lactams.
Use of fluoroquinolones
Intravenous catheterization
More than 10 veterinary staff employed
Postsurgical site infection
How do you confirm a MRSI? 3p
Culture and sensitivity using oxacillin
PCR (gold standard)
Latex agglutination testing to detect PBP2a (penicillin-binding protein)
How are burns classified?
% body surface
depth
(1 degree. superficial
2 degree. epidermis and superficial part dermis
2 degree. epidermis and deeper part of dermis
3 degree. full thickness
4 degree. full thickness with extension to muscle, tendon, bone)
What is the rule of nine in burns?
percentage of total body, surface area of burn
Head and neck, each forelimb 9%
Dorsal trunk, ventral trunk, each hind limb 18%
What is the % for local burns and % for severe burns?
Local <20%. Severe >20-30%
fill in missing words regarding burns
first degree. depth: X. appearance: erythematous, painful to touch. Healing: X, time X with X management
second degree. depth: X appearance: epidermis will X, X leakage occurs. hair follicles will X, X to touch. healing: by epithelization from the wound margin with X scar. Time X days
second degree. depth: X
appearance: skin appears x, hair follicles will X, decreased X . Healing: by X and X but X is significant without X.
third. Depth: X. appearance: skin is X, X, eschar insensitive to touch. Healing: requires intensive x intervention. Possible skin grafts and flaps
fourth degree. Depth X: appearance: x Healing: need X to prevent scaring that could restrict joint movement.
first degree. depth: SUPERFICIAL, EPIDERMIS ONLY. appearance: erythematous, painful to touch. Healing: RAPID, time REEPITELISATON IN 1 WEEK WITH TOPICAL WOUND MANAGMENT
second degree. depth: EPIDERMIS AND SUPERFICIAL PART OF DERMIS appearance: epidermis will CHARRED AND SLOUGHS, PLASMA leakage occurs. hair follicles will SPARED, PAINFUL to touch. healing: by epithelization from the wound margin with MINIMAL scar. Time 10-21 days
second degree. depth: EPIDERMIS AND DEEPER PART OF DERMIS appearance: skin appears BLACK OR YELLOW-WHITE, hair follicles will DESTROYED, decreased PAIN SENSATION. Healing: by CONTRACTION and EPITELIZATION BUT SCARRING is significant without SURGICAL INTERVENTION
third. Depth: FULL THICKNESS (ENTIRE DERMIS AND DERMIS). appearance: skin is BLACK, LEATHERY, eschar insensitive to touch. Healing: requires intensive SURGICAL intervention. Possible skin grafts and flaps
fourth degree. Depth FULL THICKNESS WITH EXTENSION TO MUSCLE, TENDON, AND BONE: appearance skin is BLACK, LEATHERY, eschar insensitive to touch (same as third): Healing: need SKIN GRAFTS AND FLAPS to prevent scaring that could restrict joint movement.
When is cardiovascular shock, pulmonary, and metabolic derangements likely to occur in burn px?
If more than 20% of body surfaces is burned or its second or third degree burns
What is an eschar? How long does it take to form?
deep cutaneous slough of tissue composed of full-thickness degenerated skin. Black, firm, thick movable crust that separates from the surrounding skin. Purulent exudates often lie beneath the eschar, particularly if it covers deep or extensive injuries, and sepsis can result if it is not treated promptly. Takes 7-10 days to form.
What are the two main local responses in burn px that are most dramatic within first 12 h?
Capillary thrombosis and plasma leakage -> burn wound oedema
List 6 systemic issues seen in burn px
Anemia, hypoproteinemia, hyperNa or hypoNa, hyperkalemia or hypokalemia, acidosis, coagulopathy, oligura, prerenal azotemia (these in first line are from SACCM)
ARDS, capillary leak, myocardial dysfunction, poor perfusion
Hypoalbuminemia, vasoactive substances (NO, thromboxane) worsen hypoxia
Marked hyperalgesia due to cytokines (IL1, IL 6, TNFa)
Anaemia (haemolysis from direct damage and through damaged microcirculation), hypoproteinaemia, hyper/hypoNa, hyper/hypoK, met and resp acidosis, oliguria, prerenal azotaemia, disseminated intravascular coagulation (DIC)
What fluid rate is recommended in the first 34 h in burn px? Both saccsm recommendation and the parkland formula.
1-4 ml/kg x % TBSA burned (SACCM)
Fluid rate 4ml/kg x TBSA for the first 24 h, with half of the amount administered in the first 8 h, the remaining over the remaining 16 h - called consensus formula (formerly Parkland formula). Reduce with 25-30% in cats
How should you treat a burn px that has just been burned?
if presents within 2 h, cool with cold water (not below 3 degrees) for 30 min under running tap (convection). (don’t use ice water and ice packs (vasoconstriction and necrosis) (conduction))
name 6 things to consider in burn victim tx
cool, fluid rate/metabolic derangements, nutrition, analgesia, antimicrobial therapy, wound care
how do you treat the wound of a first degree and superficial second degree burn?
daily lavage (hydrotherapy 8psi using 19 g needle and 35 ml syringe), conservative debridement and topical treatment initially.
Name one effect of aloe vera as topical treatment in burn px
Anti-thromboxane effect that prevents vasoconstriction and thromboembolic seeding of the dermal vasculature
In burn px: What type of activity and against which type of pathogens has silver sulfadiazine effect? Name 3 advantages and 3 disadvantages
Bactericidal. Broad spectrum, most Gram positive, most gram negative, MRSA, yeast (candida), molds
+ painless, soothing, penetrates eschar, no metabolic side effects, sustained release products available
- possible delayed wound healing, argyria (skin turns blueish), local hypersensitivity reaction
In burn px: What type of activity and against which type of pathogens has honey effect? Name 4 advantages and 2 disadvantages
Broad spectrum, most gram positive, most gram negative, MRSA.
+ improved healing rate, less wound contraction, decreased hyper granulation, increased wound strength, creates more sterile environment, provides physical barrier to wound
Honey antimicrobial due to high osmolarity, acidity, and hydrogen peroxide content. Decreases oedema, accelerates sloughing of necrotic tissue, and provides a rich cellular energy source, promoting a healthy granulation bed.
-Local hypersensitivity reaction, tissue dehydration
In burn px what should be monitored around day 2-7, and from day 7?
between day 2 and 7: check for anaemia, DIC; immune dysfunction, SIRS; infection
from day 7: check for hyperthermia, hypoxia, pneumonia, sepsis, wound demarcation
what are the most common complications in burn px? 5 p
scarring, and wound contraction. infections, hypothermia, intra-abdominal hypertension, and abdominal compartment syndrome
at what pressure should intra-abdominal hypertension be treated?
pressures > 10 cm H2O be considered mild elevations in IAP. I treat when IAP > 20 cm H2O in dogs and cats
what are the two phases in burn px according to Vaughn?
The resuscitation phase. Also called hypodynamic or ebb phase (immediate -72 h)
The hyperdynamic hypermetabolic phase . Also called flow phase (3-5 days after injury – 24 months)
What two mechanism does the body use to protect against frost bite?
Arteriovenous anastomose and vein-artery-vein triads
Name 2 causes for immune mediated and 2 non-immune mediated drug eruptions
Immunemediated: Hypersensitivity reaction I-IV like:
Toxic epidermal necrolysis, pemphigus foliceus, erythema multiforme
Haptens and prohaptens (small molecule bound to proteins) etc
Ex drugs: antibiotics, nsaid, opioids, methimazole, sulphonamides, hydralazine, vaccines, trimspulfa, cephalexin, oxytetracycline, penicillin, levothyroxine, amoxiclav
Non immunemediated: Altered arachidonic acid metabolism, complement activation, danger particles like cytokines and cell debris etc
Give 4 conditions associated with vasculitis
babesiosis, rocky mountain spotted fever, histoplasmosis, FIP, lymphoma – vaccines – food allergy – medications (human serum albumin, carbamizole, fenbendazole)
What are the 3 phases of wound healing and how long do they last? Give two examples for each phase of whats occuring
Inflammation and debridement immediate – 5 days. Haemorrhage, vasoconstriction and PLT aggregation initially, then vasodilation. Neutrophils and macrophage activity
Proliferative phase 4 days – 3 weeks. Angiogenesis, granulation tissue formation, epithelization
Maturation phase 17-20 days wound contraction, remodelling of collagen fibre bundles, progressive gain of tissue strength
What are 4 different way for a wound to heal/close
Primary closure
Delayed primary closure (after delay but before granulation tissue)
Secondary closure (after granulation tissue, usually more than 5 days)
Secondary intention healing
What are the 4 different wound classifications?
Clean: Atraumatic, surgically created under aseptic conditions (e.g., incisions)
Clean contaminated: Minor break in aseptic surgical technique (e.g., controlled entry into the gastrointestinal [GI], urogenital, or respiratory tracts) in which the
contamination is minimal and easily removed
Contaminated: Recent wound related to trauma with bacterial contamination from street, soil, or oral cavity (e.g., shearing or bite wound); can also be a surgical wound with major breaks in asepsis (e.g., spillage from the GI or urogenital tracts)
Dirty or infected: Older wound with exudate or obvious infection (e.g., abscess in a bite wound, puncture wound, or traumatic wound with retained devitalized tissue); contains more than 105 organisms per gram of tissue
What is the classification of open fractures?
Grade I: small break in skin <1 cm caused by bone penetrating inside to out, surrounding tissue mild to moderately contused
Grade II: soft tissue trauma > 1 cm contiguous with the fracture, often external trauma, a (e.g., bite wound, low-velocity gunshot injuries)
Grade III: extensive soft tissue injury, commonly in addition to a high degree of comminution of the bone (e.g., distal extremity shearing wounds, high-velocity gunshot injuries)
What is the optimal lavage pressure for a wound and how is it achieved?
7-8 psi achieved using 18-19 gauge hypodermic needle attached to 35 ml syringe (or 16 gauge needle and 35 ml syringe)
Name 4 types of non adherent dressings
Alginates, foams, hydrogels, hydrocolloids, transparent film
Name 1 contraindication each for gauze, polyester film with cotton, calcium alginates, hydrogels, hydrocolloids, foams, polyurethane films
Gauze: non appropriate with healthy granulation tissue or when trying to get wound to epithelialize
polyester film with cotton: may promote excessive granulation tissue
calcium alginates: do not use over exposed tendon, bone or necrotic tissue
hydrogels: may promote excessive granulation tissue
hydrocolloids: not for use in exudative or infected tissue, may promote excessive granulation tissue
foams: reduced granulation, may cause maceration if overlap skin
polyurethane films: may cause bacterial proliferation and may cause maceration if overlap skin
What are the uses/benefits and contraindications/disadvantages for polyurethane film?
Uses:
Occlusive but permeable to air and water vapor but impermeable to fluid and microorganisms.
Autolytic debridement
Covering for sutured wounds
Contraindications:
Because of occlusive, adherent property, may cause bacterial proliferation and tissue maceration. Should be changed every 1-3 days
Why should a tegaderm dressing be changed every 1-3 days?
Because of occlusive, adherent property, may cause bacterial proliferation and tissue maceration.
What are the uses/benefits and contraindications/disadvantages for foam dressings?
Uses: absorbent and comfortable. Used in deep wounds with minimal exudate. Promotes epithelialization and contraction.
Contraindications: reduced granulation. May cause maceration if overlapped on skin
What are the uses/benefits and contraindications/disadvantages for hydrocolloids dressings?
Uses: autolytic debridement. Increases epithelization and comfort. Promotes granulation.
Contraindications: not for use in exudative or infected wounds. Can promote exuberant granulation.
What are the uses/benefits and contraindications/disadvantages for hydrogel dressings?
Uses: absorbs minimal exudate. Autolytic debridement. Rehydrates to soften dry wounds.
Contraindications: discontinue after healthy granulation tissue is present because it can promote exuberant granulation.
What are the uses/benefits and contraindications/disadvantages for calcium alginates dressings?
Uses: absorbs heavy exudate. Pad, ribbon, or fibre forms gel when absorbing exudate. Haemostatic, favours epithelization and granulation.
Contraindications: do not use over exposed tendon, bone, or necrotic tissue
What are the uses/benefits and contraindications/disadvantages for polyester films with cotton dressings?
Uses: used primarily during epithelization phase on surgical wounds, wounds with good granulation tissue and with minimal exudate
Contraindications: may promote excessive granulation tissue
What are the uses/benefits and contraindications/disadvantages for impregnated gauze dressings?
Uses: added zinc, iodine, or petrolatum nonadherent and helps prevent desiccation. Absorbs bacteria and exudate
Contraindications: although it increases wound contraction, it can delay epithelization
What are the uses/benefits and contraindications/disadvantages for gauze dressings?
Uses: inexpensive, readily available. Wet-to-dry nonselective debridement
Contraindications: not appropriated when healthy granulation tissue is present or when trying to get wound to epithelialize
