General cutaneous surgery Flashcards
Define an abscess
a localised collection of pus
Abscesses are nearly always…
secondary to a bacterial infection, pus is full of bacteria and dead bacteria within white blood cells
What are sterile abscesses?
No bacteria are involved but an accumulation of dead and dying cells and tissues with a fibrous capsule
Describe a malar abscess
Associated with dental disease. Extraction of the offending tooth is required, usually the carnassial tooth.
Describe an anal sac abscess
Impactions of anal gland secretions can lead to abscess formation.
The abscess normally ruptures out of the skin around the anus.
Describe a cat bite abscess (CBA)
Canine teeth penetrate deep into the skin leaving only a small entry wound. The wounds quickly heals over sealing bacteria beneath the skin
Describe penetrating wounds
- as with CBA, the skin is penetrated and heals over quickly leaving bacteria to multiply beneath the skin e.g. thorn, nail etc
Describe foreign bodies
an object e.g. grass seed, wood splinter penetrates the skin; the entry hole quickly heals over sealing the foreign body within the tissues
Describe a rabbit abcess
rabbits get recurrent abscesses in the submandibular and cheek area
the pus within is much thicker and is difficult to drain and remove
commonly related to tooth root problems and/or nasolacrimal disease
What are the clinical signs of an abscess?
Local swelling
Local pain
Warmth and erythema of the overlying skin
Systemic signs – pyrexia, depression, anorexia, tachycardia
discharge
Describe treatment of abscesses
Cold (sterile) abscesses can form if antibiotics are given without lancing and releasing the encapsulated pus
Lance an abscess where it begins to ‘point’ (soft spot)
Warm compresses can encourage an abscess to point and even rupture
GA or sedation is normally needed to lance an abscess
Prepare the site surgically and lance with a scalpel blade (FNA first to confirm)
Express pus and flush cavity out well
Daily flushing and cleaning of the site, prevent a scab from forming
Abscesses need to heal from the inside out
Surgical resection of some abscesses. Rabbit abscesses best treated this way.
Describe problems that tumours can cause
The physical mass of the tumour can press on other structures in the body and cause pain or loss of function
Rapidly growing tumours can use up energy resources and cause the animal to feel unwell and depressed
Cytokines released by a tumour can cause distant physiological effects. E.g. anal adenocarcinoma and lymphosarcoma can cause hypercalcaemia, which can cause polydipsia, polyuria and renal failure.
The tumour may spread to vital organs e.g. the heart, kidneys, lung, liver resulting in loss of function and clinical signs.
Describe a benign tumour
Usually have a well developed capsule and remain in one site
Describe a lipoma
Adipose (fatty) tissue tumour
Describe a histiocytoma
Commonly seen in dogs under the age of three years, occasionally in older animals
Commonly spontaneously regress without treatment
Describe an adenoma
Benign tumour of the glandular tissue e.g. anal adenoma, adenoma of the thyroid gland
Describe a papilloma
‘Warty’ growths found on the skin, occasionally the bladder, arising from the epithelial tissue
Describe a malignant tumour
Often show ulceration, local infiltration and metastasis
Describe a carcinoma
Produced from the epithelium e.g. squamous cell carcinoma, mammary tumours (adenocarcinomas)
Describe a malignant melanoma
Strictly should be called a melanocarcinoma
Ideally, before removal, any tumour…
should be FNAed to give an indication of the type of tumour before removal so the surgical margin adjusted as needed. Skin grafts may be required
to close the deficit
Describe a pedicle graft
A pedicle graft or skin flap is a partially detached segment of skin and subcutaneous tissue
The base or pedicle of the flap maintains circulation to the skin during transfer to a recipient location
This location can be local or distant, advanced or rotated
Describe a Single Pedicle Advancement flap
A flap is undermined to the side of the defect and advanced over the wound
The defect and the sides of the flap are then sutured
Describe a Bipedicle Advancement Flap
H-plasty
As a single pedicle advancement but skin is undermined from both sides of the wound
The skin is then advanced on both sides to meet in the centre and cover the defect
Describe a rotational flap
A curved lesion is made adjacent to the wound
The length of the incision usually needs to be about four times the width of the wound
Used where the skin can only be mobilised from one side of the wound e.g. around the anus
Describe a Transposition Flap (90˚)
Transposition flaps are developed at angles of up to 90˚
They tend to be moved from the thoracic or abdominal skin to cover wounds affecting proximal limbs
Describe skin free grafts
Segments of skin are completely detached from one area of the body to ‘resurface’ another area lacking epithelial surface
No vessel attachment at all
Describe the survival of free skin grafts
Survival of the graft in the first 48 hours is by absorbing tissue fluid from the recipient bed
Later on new blood vessels grow into the graft
Post operative care is therefore vital to graft survival
Accumulation of material (blood, pus) under the graft or movement delays or prevents revascularization and often leads to non-adherence and graft necrosis
Describe a punch graft
Grafts usually taken with a punch biopsy and pushed into ‘holes’ in the granulation tissue
Describe a stamp/strip graft
Small squares or strips of skin laid onto granulation tissue with gaps between the grafts
Describe Post Operative Care of Free Skin Grafts
Analgesia must be provided
Survival of the graft depends on optimising the conditions that promote adherence and nutrition
Bandaging –
Promotes good contact between the graft and base
Minimises movement
Removes exudates with correct dressing use
Prevents soiling and bacterial contamination
Correct bandaging is very important. Too tight and blood flow is reduced, too loose and contact is not maintained between the graft and base
Complete rest (cage rest) is essential for the initial five days post surgery. Exercise must be restricted for 10-14 days
