Path 1- Integument 2

mimijegu's version from 2016-04-07 08:16

Lecture 2 continued

Question Answer
What is Pemphigus foliaceus?Acantholysis occurs in superficial epidermis resulting in subcorneal pustules (desmoglein 1)
What is pemphigus vulgaris?Acantholysis occurs in deep epidermis resulting in suprabasilar vesicles & clefts w/ tombstoning & ulceration (desmoglein 1 & 3)
How can a skin infxn cause acantholysis & what are 2 examples?Neutrophilic enzymatic destruction from skin infxn
(1) Bacterial pyoderma (Staph. & Strep.)
(2) Dermatophytosis (Trichophyton sp.)
What are Vesicles/Bulla?Fluid-filled spaces w/in or beneath the epidermis (blisters) Vesicles are <1cm. >1 cm are termed Bulla (pl. bullae)
What is the main cause of vesicle/bulla formation? What are some other causes?Main causes are viral infections (herpesvirus, poxvirus, morbillivirus, rhabdovirus, picornavirus), also could be caused by dermal/epidermal edema, frictional trauma, burns, or acantholytic dzs (pemphigus vs. infection)
What are some viruses which could cause vesicles or bulla to form? (5)Herpesvirus, poxvirus, morbillivirus, rhabdovirus, picornavirus
What is the term used to describe complete separation of the epidermis from the dermis?**Subepidermal vesicle** bullous pemphigoid
Inflammation → what is going on in the process of exocytosis?Leukocytes (mostly neutrophils) that infiltrate the epidermis migrate from the superficial dermal layer into the epidermis
Inflammation → Exocytosis is commonly accompanied by what?Spongiosis
Inflammation → If inflammation persists, what happens w/ the neutrophils?Neutrophils will accumulate w/in the epidermis to form pustules, or microabscesses (pus)
Inflammation → Aside from neutrophil accumulation, what else can form pustules & what situations cause this?Pustules may also be formed by eosinophil accumulation which is often a response to ectoparasite bites, pemphigoid rxns, or feline eosinophilic dz
Inflammation → When does Exocytosis of lymphocytes usually occur? (2)(1) Immune dzs, such as Lupus erythematosus
(2) Some chronic infections, such as Malassezia
What are crusts?Crusts are composed of dried fluid & cellular debris on the epidermal surface which indicate an exudative process
What are the two ways that hyperpigmentation occurs? (incld examples)(1) ↑ PRODUCTION of melanin, which happens w/ chronic dermatitis (allergic dermatitis) & endocrine dermatoses (e.g. hyperadrenocorticism)
(2) ↑ melanocytes such as lentigo & melanocytic neoplasia
What are some situations in which youd see hypopigmentation?Acquired loss of melanocytes (skin injury), acquired lack of melanin production (copper deficiency), or can be congenital or hereditary due to genetic causes (albinism)
Explain Pigmentary incontinenceIt is a histologic feature which refers to the loss of melanin by damage to the stratum basale w/ resulting accumulation of melanin w/in macrophages in the superficial dermis
*DERMAL atrophy is usually caused by what kind of conditions (examples?)(Thin & transparent skin) caused by CATABOLIC conditions such as severe, prolonged malnutrition (starvation), hyperadrenocorticism (Cushing’s) & long-term corticosteroid therapy (iatrogenic)
*Dermis → What is fibrosis?The gradual deposition & maturation of collagen to form scar tissue
The early stage of fibroplasia in response to injury is called?Granulation tissue
What is Exuberant granulation tissue usually called? When does this usually occur?(Aka proud flesh) may occur w/ cutaneous injury, especially on the distal limb of horses
*Explain Collagen dysplasia & which layer of skin is this a dysfxn of?(Dermis) an inherited abnormality of collagen that results in ↓ tensile strength & ↑ stretchability of the skin (e.g. Ehlers-Danlos syndrome, cutaneous asthenia)
Cutaneous asthenia aka?Collagen dysplasia (super stretchy skin)
*Explain Solar elastosis & what it results from?Caused by chronic exposure to ultraviolet radiation (solar damage) leading to increased numbers of thick, interwoven, basophilic elastic fibers in the superficial dermis
When you hear Scar think?Fibrosis
When you hear Granulation tissue think?FibroPLASIA (early healing)

Lecture 3

Question Answer
*What are 3 depositions which occur in the dermis?Amyloid
Amyloid depositions are deposited where? in who?In the DERMIS & is rarely observed in dogs & horses. (Can be triggered by a monoclonal gammopathy or plasma cell tumors (AL amyloid) or by dermatomyositis (SAA protein) )
*Mucin or hyaluron deposits where in the skin? What is it composed of? What is this condition called? When does this occur?In the DERMIS, it is an accumulation of glycosaminoglycans & accumulation in the skin is termed Cutaneous Myxedema & may occur w/ hypothyroidism or in mucinosis of the Chinese Shar-Pei dog
Cutaneous myxedema is aka & happens when?Mucin or hyaluron deposits of glycosaminoglycans in the dermis which happens in hypothyroidism or in mucinosis of the Chinese Shar-Pei dog.
*Mineralization or calcification of the DERMIS occurs in what 3 forms?Dystrophic, metastatic & idiopathic
Dystrophic calcification usually happens when? Bc of what?Result of chronic injury or degeneration. HypERadrenocorticism leads to calcinosis cutis due to collagen degeneration in the dermis deposits may occur w/in granulomatous foci
Granulomatous foci might have what kinda deposits in them?Calcium
What depositing-disorder can result from hyperadrenocorticism?Calcinosis cutis
How long does acute dermatitis usually last? What is happening during this? Main cell involved?Lasts hours to several days & involves active hyperemia, edema & migration of leukocytes, mostly neutrophils
What are 4 outcomes of acute dermatitis?Complete resolution, formation of an abscess (pyoderma), healing & replacement by scar tissue, progression to chronic dermatitis (hotspots)
*How long does chronic dermatitis last? What is the main cell involved?Lasts weeks, months, or years. Tissue destruction, fibrosis, angiogenesis & accumulation of mononuclear leukocytes (macrophages, lymphocytes, plasma cells)
*What is the yellow example he gives for chronic dermatitis?Acral lick dermatitis (sustained physical injury or self-trauma)
4 causes of chronic dermatitis?Persistent infections, often accompanied by allergic dermatitis
Formation of granulomas (infectious or sterile)
Autoimmune dermatitis (SLE, Pemphigus foliaceus)
Sustained physical injury or self-trauma (Acral lick dermatitis)
Repeated skin surface trauma (acral lick dermatitis) affects the adnexa how?Causes adnexal hypertrophy
What is the adnexa?"Skin appendages” ie hair follicles & associated glands in the skin
*Follicular dysplasia is? Usually leads to what?Abnormal development of follicles & hair shafts that frequently cause alopecia
*What are some examples of follicular dysplasia?Color dilution follicular dysplasia (mutant color alopecia) (causes clumping of melanin pigment & increased hair shaft fragility)
Structural follicular dysplasia
Atrophic follicular dysplasia (pattern baldness)
Cyclic follicular dysplasia (seasonal alopecia)
Disruption of the normal stages of hair development is usually due to what?Often caused by hormonal disorders such as hypOthyroidism or hypERadrenocorticism
*Check out picture of "inflammatory patterns of adnexa" Pay attention to where Black Dots are, they represent where the inflammation is
*What is Mural folliculitis? When is this commonly seen?Inflammation of hair follicle wall. Commonly seen w/ demodicosis or pemphigus foliaceus
*What is Luminal folliculitis? When do you usually see this?Inflammation of the follicle lumen. Most commonly associated w/ infection of the hair follicle w/ bacteria (Staphylococcus sp.), dermatophytes (Microsporum sp. Trichophyton sp.), or parasites (Demodex sp.)
*What is bulbitis? Example of a condition of this?Inflammation of the hair bulb (alopecia areata) ("spot baldness" prolly autoimmune disorder)
*What is furunculosis? How does this happen?Severe luminal folliculitis can lead to distention of the hair follicle by exudate → Subsequent hair follicle rupture can lead to a foreign body inflammatory response in the surrounding dermis, known as furunculosis
What can furunculosis lead to?Furunculosis can lead to a nodular skin mass & localized bacterial infection which is slowly responsive to antibiotic therapy & frequently causes scarring
What is Adenitis?Inflammation of a gland
What are the two types of adenitis of the skin? Briefly explain**(1) Sebaceous adenitis is inflammation of sebaceous glands (usually in dogs, prolly immune mediated, if chronic, can have loss of gland w/ scarring)
(2) Hidradenitis is inflammation of apocrine glands (Supurative hidradenitis occurs in conjunction w/ staphylococcal folliculitis & furunculosis--may be due to extension of bacterial infection from the hair follicle)
What is the 1° TARGET OF INJURY?Blood vessels
What are possible causes of vasculitis? (5)Infection
Immune-mediated injury
Toxins & drug rxns
Disseminated intravascular coagulation (DIC)
Idiopathic - most cases have unknown cause
Which animals are most often affected by vasculitis?Dogs & horses
What are CS of vasculitis?Edema, hemorrhage, ischemia & infarction
**What are three classic examples/causes of vasculitis?(1) Type III (immune complex) hypersensitivity during SLE
(2) Endotheliotropic infections (e.g. Rickettsia rickettsii, herpesviruses, FIP virus)
(3) Bacterial embolism (e.g. Erysipelothrix rhusiopathiae)
What is Panniculitis?Inflammation of the subcutaneous adipose tissue
**What are some causes of panniculitis? (6)Infectious - bacteria & fungi
Immune-mediated - SLE
Physical injury - trauma, injxn sites, foreign bodies
Nutritional disorders - Vit E deficiency (feline pansteatitis)
Pancreatic dz - pancreatitis, pancreatic carcinoma
Idiopathic - aka sterile panniculitis
What are some CS of panniculitis?Painful, palpable nodules that can become ulcerated & drain an oily or hemorrhagic material. Animal may be pyrexic w/ lethargy & inappetence
*What are the 2 ways an animal can get Congenital alopecia & hypotrichosis?(1) Genetic
(2) Non-genetic
*What are the 2 known causes of non-genetic congenital alopecia & hypotrichosis?(1) Maternal iodine deficiency
(2) In utero pestivirus infection, i.e. BVD & CSF (wouldnt have thought iodine & viruses would kill your hair)
*What are the three Collagen dysplasia disorders?(All are rare) Hyperelastosis cutis, Dermatosparaxis & Cutaneous asthenia
*Which breed do you see mucinosis in?Shar-pei (may rarely present w/ severe forms resulting in fragile skin)
Epidermolysis bullosa is aka? What is going on? Who’s prone?"Red foot dz" where you get bullae from minor mechanical trauma. Caused by structural defects of the dermo-epidermal basement membrane zone. In cattle, sheep, dogs, or cats
Epitheliogenesis imperfecta is aka? What is happening?Aka Aplasia cutis, failure of the epidermis to develop completely, resulting in areas of exposed dermis. Usually die from dehydration & infection, occurs in most domestic spp
*Congenital hypertrichosis → Affects who? Aka? What is happening?Excessively hairy lamb. Usually caused by in utero pestivirus infection (border dz virus). Lambs also have cerebral cavitation, poor conformation & tremors. Aka border dz or hairy shaker dz
*Dermatosis Vegetans → Affects who? What is happening?Inherited disorder which affects YOUNG PIGS, specifically Landrace pigs. Characterized by vegetating skin lesions, hoof malformations & giant cell pneumonia. Lesions either present at birth or develop at 2-3mo of age (VEGETA LANDS on the PIG to crush its skin...# of lesions can be over 9000 LOL)