Integument Flashcards
IN01-04
start at IN03
name the diagnostic technique:
perform on pruritic cases;
detects surface ectoparasites;
stiff brush (sterile nail or denture brush);
sweep hair/debris to petri dish;
examine using microscopy
groomings/coat brushings
name the diagnostic technique
indicated if broken hairs, crusts, scales, alopecia;
includes hair follicles (site assoc with dermatophytes);
from margins of fresh lesions;
submit in sterile bottles;
microscopy, fungal PCR and culture
hair pluck
name the diagnostic technique
useful in pruritic cases;
ID’s burrowing mites;
moisten with 0.9% saline;
do it until specks of blood appear;
microscopy, PCR and fungal culture
skin scrape
name the diagnostic technique
useful for suspected bacterial lesions;
amies transport medium;
maybe contaminated by surface commensals;
improved results with deeper ones/aspirates;
submit for culture and sensitivity
swabs
what medium should be used for fungal cultures
Sabouraud’s medium
(Dermatophytes changes agar from amber to red)
name the diagnostic technique
attach syringe to 19G or 20G needle;
advance to centre of mass,
apply maximal suction repeatedly for few seconds,
withdraw needle,
draw air into syringe and release through needle onto slides;
results often disappointing;
useful for melanomas
aspirates
name the diagnostic technique
use fresh lesion or remove dry surface epithelium with blade;
discuss fixing/staining slides with pathologist
impression smear
name the diagnostic technique
useful for culture, histopath, IF, IGC, VI;
often useful to discuss sampling technique with pathologist;
includes punch, shave, wedge, excision
biopsy
name the diagnostic technique
no skin prep;
mark, sedation (avoid local directly into lesion);
5-9mm biopsy;
snip tag of fascia;
10% formalin;
sutures not required
punch biopsy
name 2 lice species affecting horses
- Damalinia equi (aka Bovicola equi)
- Haematopinus asini
name the pruritic disease
louse infestation;
biting and sucking lice
pediculosis
what is the treatment for lice?
topical treatment with synthetic pyrethroids;
2 treatments at 14d intervals
(Deosect - cypermethrin)
how to diagnose Chorioptes bovis on horses
microscopic exam of coat brushing/superficial scrap
name 3 treatments for Chorioptes bovis
- topical ivermectin (Mallender’s solution)
- permethrins
- clip hair
name the pruritic disease
seasonal - July/August;
pruritis of head/limbs;
orange/brown colour to legs from mites + serum accumulation on legs
harvest mites
(Tombicula autumnalis)
name the pruritic disease
adult migrates from rectum to lay eggs;
intense perineal pruritis;
perineum rather than tail;
diagnose with tape
Oxyuris equi - Pinworm
name the immunotherapy option to treat pruritic diseases
unlicensed vaccine (licensed for ringworm);
2 injections, 14d apart;
prior to midge seasom (Jan/Feb);
deep IM;
imported under special import certificate
Insol Dermatophyton vaccine
name the pruritic disease
type 1 hypersensitivity;
extreme pruritis;
diagnosis by exclusion, ID skin tests (RAST or ELISA on serum);
treat by removing contact or hyposensitisation to allergen;
corticosteroids
atopy
name 8 causes of alopecia
- Dermatophilus congolensis (rain scald)
- ringworm (Trichophyton equinum var equinum)
- Microsporum gypseum
- Occult sarcoid
- alopecia areata
- multisystemic epitheliotrophic eosinophilic disease (MEED)
- chemical dermatoses
- linear keratosis
name 3 ways to diagnose Microsporum gypseum as cause fo alopecia
- hair pluck and skin scrape for microscopy ad fungal culture
- some fluoresce with Woods lamp
- PCR
how to treat Ringworm?
Imaverol
(4 washes at 3d intervals)
name the cause of alopecia
rare autoimmune skin disease with thinning of mane and tail and circumscribed alopecia;
no effective treatment
alopecia areata
name the cause of alopecia
often GIT and skin;
pruritis, alopecia and systemic signs;
diagnose with biopsies of skin +/- GIT; guarded prognosis
Multisystemic Epitheliotrophic Eosinophilic Disease (MEED)
name the cause of alopecia
rare, idiopathic, possible inherited, often quarter horses
linear keratosis
name the cause of nodule/tumour/swelling
complex immune-mediated/allergic response to various allergens;
isolated cases respond to steroids (0.1mg/kg dexamethasone);
recurrent cases more challenging
urticaria
name the cause of nodule/tumour/swelling
most common skin tumour of horses;
6 types: occult, verrucose, nodular, mixed, fibroblastic, malevolent
sarcoids
name the 6 types of sarcoids
- occult
- verrucose
- nodular
- mixed
- fibroblastic
- malevolent
name the cause of nodule/tumour/swelling
common, usually along back;
nodules assoc with degenerate collagen;
biopsy only if necessary;
Tx rarely indicated
eosinophilic collagen necrosis
name the cause of nodule/tumour/swelling
cutaneous cyts;
contains cheese-like material and hair
Dermoid Cyst
name the cause of nodule/tumour/swelling
developmental cystic structure of epidermis;
common in false nostril
epidermoid cyst (atheroma)
name the cause of nodule/tumour/swelling
swelling in temporal region from tooth germ tissue;
drains through skin near ear;
surgical removal
dentigerous cyst
name 3 treatments for squamous cell carcinomas
- surgery
- cytotoxic injections
- radiation
name the cause of scaling and crusting
autoimmune disease;
autoantibodies to cell membrane of epidermal cells;
exfoliative dermatitis, vesicles, pustules, scaling, crusting;
biopsy - acantholytic keratinocytes
pemphigus foliaceus
what is the treatment for pemphigus foliaceus?
corticosteroids - prednisolone
(2-4 mg/kg)
name the cause of scaling and crusting
caused by UV radiation;
facilitated by lack of pigment;
prevent with sunblock
sunburn
this is a potent photodynamic agent produced in digestion of chlorphyll;
usually detoxified and excreted by liver;
liver failure allows accumulation in skin;
causes severe damage to white areas
Phylloerythrin
name 5 causes of pastern dermatitis
- chorioptes
- photosensitisation
- mud fever
- pastern leucocytoclastic vasculitis
- MEED
name the cause of pastern dermatitis
Dermatophilus congolesis;
or mixed infections with Staphylococcal spp and Streptococcal spp.
mud fever (‘Greasy Heel’)
name the cause of pastern dermatitis
affects unpigmented distal limb;
role of UV light;
clinical signs often diagnostic;
can biospy
pastern leucocytoclastic vasculitis
name the skin disease
draft types;
abnormal lymphatics cause swelling, hyperkeratosis and fibrosis;
often concurrent Choriptes bovis;
treatment challenging
Chronic Progressive Lymphoedema
name the cause of limb swelling
inflammation of cutaneous lymphatics;
often with small wound but not always;
usually hindlimbs;
leg can be 2-3x normal size
lymphangitis
name 6 treatments for lymphangitis
- abx (tetracyclins vs TMPS)
- NSAIDs
- corticosteroids
- hydrotherapy
- leg wraps
- exercise
name the cause of limb swelling
generally results from small infected wound;
causes painful swelling, pyrexia, inappetance
cellulitis
name 6 treatments for cellulitis
- abx
- NSAIDs
- corticosteroids
- hydrotherapy
- wound management
- bandages
name the cause of limb swelling
inflammation of vessel walls, commonly immune-mediated;
causes oedema, necrosis and ulceration of limbs and mucosae;
Tx: corticosteroids, symptomatic treatment
vasculitis
name the cause of limb swelling
immune-mediated vasculitis associated with with recovery from URT infection (usually strangles);
usually 2-4wks after infection
purpura haemorrhagica
start of IN01
name the 3 broad categories of wound healing
- inflammation and debridement
- repair
- maturation
name the stage of wound healing
initiated with acitvation of clotting cascade;
phagocytic cells enter wound, removing foreign matter and bacteria;
wound increases in diameter, inflammation evident as heat, swelling and/or redness;
therapeutic goal is to minimise duration of this phase as much as possible
inflammation debridement
name the stage of wound healing
granulation tissue formation and fibroplasia;
provides surface for epithelialisation to occur;
slower in limb wounds than trunk wounds and slower in horses compared to ponites;
therapeutic goal is to enable granulation tissue to cover wound ;
created by providing moist, hypoxic environment through bandaging
repair
name the stage of wound healing
epithelisation and contraction of wound;
can be very slow - with time, rea becomes more fibroblastic (scarred) and hair may regrow;
therapeutic goal should be to allow epithelial cells to migrate as easily as possible across wound;
minimise destruction and minimise distance epithelial cells need to travel
maturation
what is the toxic dose of lidocaine
8-10mg/kg
name the 4 steps of preparing the wound
- clean wound of gross debris and cover in water-soluble sterile lubricating gel or gauze
- clip hair surrounding wound
- clean wound edges with iodine or dilute chlorhexidine
- lavage wound with warm isotonic fluids
name 4 uses of u/s with wound management
- r/o involvement of tendon and ligaments
- ID foreign material
- ID evidence of infection
- assess blood flow (w Doppler)
name 4 uses of radiography with wound management
- r/o potential fractures
- metallic foreign material
- positive contrast for penetrating injuries with synovial involvement
- sequestrum formation (chronic non-healing wounds)
what is the purpose of saline distension of synovial structures
determine synovial involvement with the wound
where should the needle be placed for saline distension of synovial structures in relation to the wound?
site distant from wound
(NOT through wound to avoid iatrogenic contamination)
name 2 reasons why distal limb wounds are more difficult to manage
- risk of damage of deeper structures
- exuberant granulation tissue formation (‘proud flesh’)
when is the best time for evaluation of periosteal and/or bone injury?
2-3wks post-injury
name 3 types of debridement
- mechanical
- autolytic
- biosurgical
name 2 types of mechanical debridement
- surgical
- wet-to-dry dressings
name the type of debridement
most traumatic method;
non-selective, removing not just contamination but also vital healing factors and fibroblasts;
associated trauma can create a viscious cycle of persistent inflammation
mechanical debridement with dressings
name the type of debridement
allow wound to ‘fester’ by maintaining moist wound environment;
very selective - preserves all vital tissue and healing factors, leukocyte phagocytosis and enzymatic reactions clear away necrotic tissue and microorganisms;
ineffective when gross amounts of necrotic debris present
autolytic debridement
name the type of debridement
maggot therapy;
greenbottle fly larva (Lucilia sericata);
function by secreting proteolytic enzymes;
used for necrotic, infected or chronic nonhealing wounds
biosurgical debridement
name 2 instances when systemic antibiotic therapy is indicated for a wound
- degree of infection exceeds efforts of local control
- local soft tissue infection or systemic infection apparent
what is the most commonly cultured bacteria in subcutaneous wounds
Staphylococcus spp.
name 2 options for empirical treatment of infected subcutaneous tissue wounds while awaiting results of C&S
- penicillin
- TMPS
name 3 bacterias less commonly cultured in wounds of subcutaneous tissue
- Streptococcus spp
- gram-neg anaerobes
- Corynebacterium pseudotuberculosis
name the 3 most commonly cultured bacteria in wounds including synovial cavities or bone
- gram-neg enteric genera
- Streptococcus spp
- Staphylococcus spp
what is the empirical treatment for wounds including synovial cavities or bone while awaiting results of C&S
beta-lactam abx + aminoglycoside
what is the empirical treatment for cellulitis and septic myositis due to Clostridium spp
high dose penicillin and metronidazole
(aggressive surgical debridement and aeration)
name 5 benchmarks for wound response to therapy
- resolution of systemic signs of inflammation
- continued improvement in comfort and function
- resolution of local signs of infection and purulent discharge
- negative culture results
- normal rate of wound healing
name the type of wound closure
favoured whenever possible, provided no gross evidence of infection;
greater risk of dehiscence, but potentially salvages more tissue and creates biological bandage
primary closure
name 4 characteristics of wounds sutiable for primary closure
- minimal contamination
- good blood supply
- moderate tissue loss
- no to moderate tension on wound edges
name the type of wound closure
not ideal;
wounds in horses heal primarily by epithelialisation rather than by contraction;
forms more extensive scar that is weaker and lacks normal skin adnexa (pigment, sweat, sebaceous glands)
second-intention healing
name 4 characteristics of wounds suitable for second intention healing
- gross contamination
- extensive tissue loss
- high tension on wound edges
- dehiscence following primary closure
name the type of wound closure
closure delayed for 1-3d;
allow better preparation of wound bed to increase success of closure;
reduce bacterial burden and prevent biofilm formation
delayed primary closure
what wounds are suitable for delayed primary closure
wounds suitable for primary closure but with marked: contamination, oedema or drainage
name 5 reasons wounds heal faster when bandaged
- minimises oedema
- absorbs exudate
- maintains temp and moisture
- immobilises wound
- protects from further contamination and trauma
name the 4 main types of primary dressings
- debridement dressings
- moistening dressings
- granulation and wound contraction dressings
- epithelialisation dressings
name the type of primary dressing
remove bacteria and dead tissue from wounds
debridement dressings
name the type of primary dressing
moisten wound and facilitate autolytic debridement
moistening dressings
name the type of primary dressing
encourage granulation tissue formation and wound contraction
granulation ad wound contraction dressings
name the type of primary dressing
incr surface temp of wound, encouraging epithelial cell migration
epithelialisation dressings
name the debridement dressing
medical grade, irradiated to destroy microorganism spores;
hypertonic: debrides wounds;
reduces bacterial number;
growth factor properties but poorly understood;
use once granulation has begun;
infected wounds
manuka honey
name the debridement dressing
hypertonic saline;
non-selective debridement;
osmotic activity;
for wounds with considerable necrotic tissue or abscesses
curasalt
name the moistening dressing
hydrogel, completely occlusive;
promotes autolytic debridement and white blood cell migration;
for desiccated or contaminated wounds short term, until wound is moist
Intrasite
name the granulation dressing
calcium alginate;
stimilates myofibroblast/epithelial cells;
heavily exudative wounds in granulating phase, absorbs 20-30x its weight
Algisite
name the epithelialisation dressing
hydrophilic foam centre, non-adhesive, non-occlusive;
promotes haemostasis, enhances epithelialisation, minimises proud flesh;
use only once necrotic material or bacterial load is removed and healthy granulation is established
Allevyn
name the primary dressing
cotton cellophane, non-adhesive, non-occlusive;
simply a wound cover;
non-exudative healing wound
Melolin
name 3 indications for casting a wound
- high motion areas
- wound involving supporting structures, such as tendons and ligaments
- skin grafts to help stabilise the graft and reduce shear forces
name the tissue
this is due to inefficient, protracted inflammatory response, as well as imbalance in collagen homeostasis;
delays wound contraction and inhibits epithelialisation
exuberant granulation tissue
name 3 risk factors for exuberant granulation tissue
- high motion areas
- wounds with foreign material, chronic infection or chronic inflammation
- distal limb wounds
start of IN02
what is the most common equine tumour?
sarcoids
(90% of all skin neoplasia)
what is the histology of sarcoids?
fibroblastic type tissue
what is the causative agent of sarcoids?
Bovine Papilloma Virus
(BPV1 and 2)
name 4 horse breeeds with a predilection for sarcoids
- Apploosas
- quarter horses
- TB
- Arab
how are sarcoids transmissed
BPV-1 DNA on flies
name 5 common places for sarcoidosis lesions
- head
- groin
- prepuce
- axillae
- neck
name 6 types of sarcoids
- occult
- verrucose
- nodular
- fibroblastic
- mixed
- malignant/malevolent
name the type of sarcoid
frequently on head/groin;
hairless area, thickened skin, rough surface;
superficial dermis only;
very slow growing;
topical treatment with chemotherapy or immune modulation
occult
name the type of sarcoid
dry, scaling, warty;
hyperkeratosis of dermis;
broad base;
head/axilla
verrucous (warty)
name the type of sarcoid
subcutaneous and more mobile;
can be shelled out;
occasonally erupt through skin;
Tx with resection +/- chemotherapy
type A nodular
name the type of sarcoid
ulcerated fleshy appearance;
aggressive;
pedunculated or a broad base;
occur on underside of body;
more aggressive and most require early aggressive treatment - resection with chemo/cryo/immune modulation
fibroblastic
name 3 conditions that give a better prognosis for sarcoids
- treated early
- combined therapy (Sx resection + chemotherapy)
- young horse (<6y)
name 4 treatment options for sarcoids
- resection
- cryotherapy
- chemotherapy
- brachytherapy
name 3 sarcoid conditions where you could choose to do nothing as Tx
- if no interference with tack
- not ulcerated
- very occasionally self-resolving
what size surgical margins should be used for conventional resection of sarcoids
2cm
name the sarcoid treatment
only for lesions with limited size and depth;
risk damage to surrounding structures;
scarring common (white hairs);
time consuming and tedious;
3x freeze thaw cycles
cryosurgery
name the sarcoid treatment
very caustic;
applied topically on several occasions;
obtained on case by case basis from Derek Knottenbelt;
causes skin necrosis and scarring;
painful and strongly resented
sarcoid cream
(AW5-LUDES)
name the sarcoid treatment
inhibits DNA synthesis;
applied topically daily for up to 3wks
5-fluorouracil
name the sarcoid treatment
anti-viral agent;
68% regression (not repeatable result);
best in small occult/verrucose
acyclovir
name the sarcoid treatment
immune response modifier;
60% response
imiquimod
name the sarcoid treatment
cytotoxic and immune modulation - alkaloids;
66% regression;
better for smaller lesions
Bloodroot
name the sarcoid treatment
inject intra-lesionally on several occasions;
electrochemotherapy;
biodegradable beads
Cisplatin
name the sarcoid treatment
immune stimulation likely;
periocular sarcoids ONLY (>85% success);
2-3 injections 2-3wks apart;
can get severe anaphylactoc reaction on repeat Tx’s
BCG injection
name the sarcoid treatment
gold standard;
free iridium wires;
low dose;
no longer available in this country
interstitial brachytherapy radiation
name the sarcoid treatment
peri-ocular sarcoids;
96% success at 1y;
radioactive source driven from shielded safe in tumour via catheter;
5-10min
HDR brachytherapy at AHT
radiation
name the skin tumour
80% of grey horses >15y have them;
10% of skin tumours in horses
melanoma
name 3 predeliction sites for melanomas
- parotid area
- around anus/vulva/under tail
- inner thighs/prepuce
name the melanoma classification
dermal melanoma;
discrete, slow growing, only cause problems if distoring normal function e.g. around anus, in guttural
benign
name the skin neoplasia
black lesions - can be ulcerated;
solid or soft;
black on cut surface;
occasionally amelanotic
melanoma
name 4 treatment options for melanoma
- surgical excision
- cryotherapy
- chemotherapy
- vaccine
name the melanoma treatment
curative for discrete dermal lesions;
de-bulking large lesions causing a physical obstruction (perineum/prepuce)
surgical excision
name the melanoma classification
only if lesion limited size and depth;
may need to repeat;
combine with de-bulking surgery?
cryotherapy
name the melanoma classification
intra-lesional cisplatin;
toxic to administrator, CARE when handling
chemotherapy
name the melanoma treatment
recently approved for use in horse;
insufficient data to be sure/promising
vaccine
name 5 aetiologies for squamous cell carcinomas
- UV radiation
- papilloma virus
- chronic irritation
- previous wound
- smegma?
name 3 common distributions of squamous cell carcinoma
- non-pigmented skin
- head/eye
- external genitalia
what is the most common neoplasm of the penis and prepuce?
squamous cell carcinoma
