Integument (Ginn) Flashcards

1
Q

objectives

A
  • recognize and describe gross lesions
  • diseases common per species
  • form ddx
  • know primary vs secondary lesion: give/recognize example of each
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2
Q

Common presenting complaints

A
  • odor
  • hair loss
  • itchiness
  • pigment change
  • lumps, bumps
  • scales
  • crusts
  • sores
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3
Q

Functions of skin

A
  • Temp and blood pressure regulation
  • flud regulation
  • protection: barrier
  • sensation
  • nutrient metabolism
  • immune functions: SALT
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4
Q

Microscopic anatomy of skin

A
  • Epidermis
    • can involve hair follicles (they are invagination of epidermis)
  • Dermis
  • Adnexa
    • hair follicle
    • apocrine gland
    • sebacious gland
  • Panniculus
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5
Q

basal layer of skin

A

germinal layer

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6
Q

Epidermis

A
  • Stratum corneum
  • Stratum granulosum
  • Stratu spinosum
  • Stratum basale
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7
Q

Diagnostic approach

A
  • Signalment
    • age of patient, breed, sex, color
    • age of lesions
  • History
    • duration, pruritus, other animals
  • Distribution and character of lesions
  • Response or failure to respond to treatment
  • overall health status
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8
Q

Blue dobermans

A

follicular dysplasia

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9
Q

Primary lesions most useful for

A

dx of dz

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10
Q

Secondary lesion

A

evolution

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11
Q

Acanthosis

A
  • Epidermal change: hyperplasia
    • usually affects stratum spinosum
    • regular
    • Irregular: yeast
    • papillated
    • pseudocarcinomatous
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12
Q

Yeast infection

A
  • acanthosis - lichenification
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13
Q

Hyperkeratosis

A
  • inc width of stratum corneum
    • orthokeratotic: too much, or not exfoliated
    • parakeratotic: too much with retained nuclei
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14
Q

Ichthyosis

A
  • congenital dz too much growth stratum corneum
  • good env for microbe growth and infections
  • orthokeratotic

*golden retrievers

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15
Q

Superficial necrolytic dermatitis

A
  • hyperkeratosis of foot pads
  • metabolic dz
  • assoc with liver disease
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16
Q

Dyskeratosis

A
  • premature keratinization of cells in epidermis
  • epidermal change
  • can be precancerous change
  • often see with parakeratosis as well
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17
Q

Necrosis

A
  • Epidermal changes
  • full thickness
  • apoptosis: single cell or clusters of cells
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18
Q

Erythema multiforme

A
  • tissue reaction to something
  • scattered, transepidermal reaction
  • Clinically
    • erosions
    • ulcers
    • crusts
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19
Q

Cutanous atrophy

A
  • fewer cells, smaller cells
  • epidermis
  • dermis
  • follicles
    • alopecia

*associated with cushings

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20
Q

Edema

A
  • Epidermal changes
    • intercellular = spongiosis
    • intracellular
      • hydropic degeneration
      • ballooning degeneration
  • could lead to sub-epidermal vesicle
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21
Q

Full thickness epidermal necrosis

A
  • toxic
  • burn
  • vasculitis
  • painful, life-threatening
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22
Q

Acantholysis

A
  • loss of cohesion between keratinocytes due to breakdown of cell to cell attachments
  • two main mechanisms
    • type II hypersensitivity: pemfigus foleacious
      • diff from infection
    • enzymatic destruction
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23
Q

Pemphigus foliaceus

A
  • primary lesion is pustule
    • secondary lesion is crust
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24
Q

classic distribution of pemfiigus foleaceus

A

across nasal planum

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25
vesicles/bullae
* epidermal changes * fluid filled * within epidermis or at epidermal/dermal junction
26
Vesicular or pustular pathogenesis
* Marked spongiosis, hydropic or ballooning degeneration * Enzymatic destruction * Immune destruction * acantholysis * other * mechanical destruction * burn * friction * Genetic structural defects
27
Vesicle
* Severe epidermal edema * severe contact hypersensitivity * sting/bite (type 1)
28
Epidermal-dermal separation
* immune mediated * primary lesion: vesicle * secondary lesion: ulcer
29
Pustules
* epidermal changes * Pustule * neutrophilic: infection * eosinophilic: atopy, hypersensitivity * pautrier's microabscesses: malignant leukocytes * crust
30
changes in pigmentation
* hyperpigmentation * chronic inflammation * idiopathic * hypopigmentation * prob with basal membrane * only pigmented part of skin
31
Follicular changes
* Hyperkeratosis * Atrophy * Folliculitis * Furunculosis * Dysplasia
32
DDX folliculitis
1. bacterial infection 2. dermatophytes 3. demodecosis
33
Folliculitis/furunculosis
* grossly, folliculocentric papules or nodule * patcy alopecia * ulcerative draning lesions in severe cases * inflammation targets hair follicle * leukocytes are within the wall or lumen of follicle * furunculosis * wall of follicle is destroyed by infiltrate and contents of hair follicle are in dermis
34
Dermal changes
* Inflammation * Edema * urticaria/Angioedema * immunologic (Type 1) and nonimmunologic causes * Mucinosis: chinese shar pei * Collagen * fibrosis * degeneration * mineralization * Elastin: elastosis * calcinosis cutis * hyperadrenocorticism * Subcutis * panniculitis * fat necrosis
35
Vessels
* Vasodilation * erythema, edema * Vasculitis * thrombosis * ischemia * edema * hemorrhage * atrophy
36
When bx
* devastating dz * neoplasm * unsuccessful tx * immediate answer * primary lesions, leading margins, edges of ulcers, crusts * multiple sites
37
Pattern DX of skin and disease
* Based on types of cells present and their distribution in conjuction with types of changes discussed * Rarely pathognomonic * suggestive of pathogenesis and categories of disease
38
Cellular infiltrates
* Neutrophils * active inflammation * Eosinophils * allergic or ectoparasites * Mononuclear phagocytes * persistent antigen in tissue * Lymphocytes/plasma cells * Mast cells * resident cells, hypersensitivity
39
Perivascular Dermatitis
* most common type * generic response to skin injury * suggests **hypersensitivity** * aggregates of inflammatory cells around vessels * acute/chronic
40
Interface dermatitis
* hydropic degeneration/apoptosis in basal layer * band of lymphs, plasma cells, macs at epidermal/dermal junction * pigmentary incontinence * +/- vesicles at interface \*almost always immune mediated
41
Interface dermatitis pathogenesis
* cytotoxic T-cell attack on keratinocytes or melanocytes, or basement membrane components * non-immune mediated damage * unknown
42
Uveodermatologic syndrome
* akitas * attack on melanocytes * uveitis is painful
43
Interface Dermatitis Discoid lupus
* depigmentation around face and nose
44
**Whats the target of interface dermatitis?** **TQ**
* Anything at the basal region, dermal epidermal junction
45
**Common pathogenesis in interface dermatitis?**
* Immune mediated * DKH: melanocytes * Discoid lupus * systemic lupus \*depigmenting
46
Vasculitis
* Leukocytes within walls of capillaries and venules * evidence of vessel damage * edema/hemorrhage * fibrinoid necrosis/thrombosis * leukoclasis * Overall skin changes will reflect degree of vascular damage * mild-atrophy and alopecia * severe-cutaneous infarction and ulceration * If multicentric, lesions at * tail * footpads * ears \*vasculitis common in dogs and horse
47
Vasculitis pathogenesis
* Type III hypersensitivity: immune complex deposition in vessels * Primary bacterial skin disease * bacterial septicemia * systemic infection with endotheliotropic organism * rickettsia
48
Vasculitis-pigs
* Erysepalothrix rhusiopathiae - septic emboli
49
Nodular to diffuse dermatitis
* dermis +/- panniculus * have nodules or diffuse infiltrates of leukocytes * Types of leukocytes present help point to a cause * Pathogenesis * persistence of antigens in tissue stimulate a cell mediated immune response
50
Nodular to diffuse dermatitis causes
* Fungi - zygomeycetes, others * deep pyo * higher bacteria - acid fast bacteria * parasites * protozoans * oomycetes * pythium, lagenidium * Algae * idiopathic - sterile * foreign material * neoplasms * histiocytic * eosinophilic granulomas
51
Dematiaceus fungi
* fungi pigmented in tissues * nodular to diffuse dermatitis * ex: horse traumatic implantation
52
Vesicular or pustular
* Vesicles or pustules are within or below the epidermis * intraepidermal * subcorneal * suprabasilar * subepidermal: splits epidermis and dermis
53
Vesicular or pustular pathogenesis
* marked spongiosis, hydropic or ballooning degeneration * enzymatic destrution * immune destruction * mechanical destruction * burn * friction * genetic structural defects
54
Vesicular or pustular, determining specific process
* need to know * level of vesicle formation * degree and type of celular infiltrate * signalment * distribution of lesions needed to determine specific dz process present
55
Level of vesicle is critical
to determine specific disease process present
56
Subcorneal vesicle/pustule
* superficial pyoderma * pemphigus foliaceus
57
Suprabasilar vesicle/pustule
* pemphigus vulgaris
58
Subepidermal vesicle/pustule
* bullous pemphigoid * SLE (systemic lupoid erythematosus) * TEN (Toxic epidermal necrosis) * burns * EB (epidermal lysis bullosa)
59
TEN vs EB
* TEN: epidermis dead * EB: viable epidermis
60
Folliculitis/furunculosis
* grossly, folliculocentric papules or nodule * patchy alopecia * severe cases may have ulcerative draining lesions * Inflammation targets hair follicle * leukocytes are within the wall or lumen of the follicle * furunculosis: wall of follicle destroyed by infiltrate and contents of hair follicle are in dermis
61
Folliculitis/furunculosis
* colonization of hair follicle by organism most common * bacteria, dermatophytes, mites * immune mediated * idiopathic
62
Folliculitis/furunculosis other causes
* feline acne * pelodera * arthropod bites (common in fl) * eosinophilic folliculitis
63
**What are most common causes of folliculitis in dogs?** **TQ**
1. **Bacteria** 2. **Dermatophytes** 3. **Mites**
64
Panniculitis
* Subcutaneous fat focus of inflammation * Grossly-papules and nodules that drain * may have oily exudate * Histologically * inflammation of subcutis - nodular to diffuse * same list of agents as nodular to diffuse * part of systemic dz * pancreatitis * idiopathic sterile nodular panniculitis
65
Commn DDX for panniculitis in cats
* Atypical mycobacteria * Nocardia
66
Atrophic Dermatoses
* symmetric hypotrichosis, thin skin * comedones * telangiectasia * hyperpigmentation * focal atrophic dermatotsis - partial ischemia
67
Atrophic dermatoses most common cause
Hormonal disturbance
68
Atrophic dermatoses
* epidermal and follicular atrophy with hyperkeratosis * sebaceous gland atrophy * hyperpigmentation * may or may not se inflammation * hormonal imbalance * hyperadrenocorticism * hypothyroidism * sex hormone imbalance * ischemia if focal * need additional clinical and biochemical info for definitive dx in most cases
69
Cats hyperadrenocorticism
**fragile skin**