Endocrine diseases of the skin Flashcards
What is primary hypofunction?
associated with destruction of endocrine tissue
What is secondary hypofunction?
Destruction of another endocrine organ
What is secondary hyperfunction?
Excessive production of trophic hormones in another endocrine organ
What does endocrine dysfunction cause?
failure of target cell response
Give 4 examples of pathological mechanisms of endocrine disease
- Endocrien hypersesnitivity
- Abnormal hormone degredation
- Endocrine dysfunction
- Hypersecretion of hormones
- Iatrgenic syndromes of hormone excess
What is pars intermedia adenoma most likely to affect?
- Older horses
- Female more than male
What are the two ‘possibilities’ of pars intermedia adenoma?
- Inactive = hypopituitarism + diabetes insipidus
- Active = secretes ACTH -> causes adrenal cortical hyperplasia and increased cortisol
What are some of the clinical signs of active Pituitary pars adenoma?
- Laminitis
- Hirsuitism
- Hyperhidrosis
- Somnolence
- Pyrexia
- Muscle weakness/ abnormal fat distribution
What is the most common primary hypothyroidism tumour?
Lymphocytic thyroiditis
What causes congenital hypothyroidism?
Lack of TH-negative feedback on TSH
Name 5 dermal diseases associated with hypothyrodism
- Keratinisation disorders
- Secondary infections
- Hair coat abnormalities
- Delayed wound healing
- Myxoedema
What does a keratinizing disorder cause?
Reduction in thyroid hormones -> alteration in lipogenesis + sebum production -> alteration in skin lipid levels
What two **other things ** does a keratinizing disorder cause?
- Hyperkeratosis
- Seborrhea, ventral comedones, otitis externa
What stage of hair growth does TH stimulate?
anagen/ the active phase of hair growth
What does a reduction in Th do to hair growth
Increases telogen = the rest phase so hairs are easily dislodged
Where are the most common points of alopecia?
- Areas of pressure = nose, neck, pinnaer, flanks, ventrum, perineum and tail
- also associated with hyperpigmentation
What does myxoederma cause?
deposition of mucin the dermis and subcutis
How does reduced TH cause altered wound healing?
- Altered collagen synthesis
- Abnormal fibroblast function in wound healing
What does a secondary infection cause?
- Altered cutaneous barrier
- reduced immune function
- seborrhea
- may be due to a bacterial infection e.g malassezia, dermatitis
What are the clinical signs pf feline hyperthyroidism?
- Poor grooming/ over grroming
- Increased claw growth
- Excessive shedding
- Thin skin
What are three tumours that cause cushing syndrome?
- Bilateral adrenocortical hyperplasia
- Adrenocortical neoplasms
- Exogenous glucocorticoids
Name 5 dermal diseases associated with hyperadrenocorticism
- Keratinisation disorders
- Hair coat abnormalities
- Dermal atrophy
- Calcinosis cutis
- Delayed wound healing
Name 4 hair coat abnormalities that arise from adrenal gland disorders
- Inhibition of anagen
- Bilateral symmetrical
- Over points of wear
- low rate of hair growth + alopecia
Name 4 things that cutaneous atrophy causes
- Anti-enzymatic protein catabolism
- Atrophy of the epidermis and pilocebaceous apparatus
- loss of collagen and elastin fibres in the epidermis and subcutis (thin fragility of epidermis and dermis)
- Hyperpigmentation
What is calcinosis cutis?
Dermal deposition of calcium in the
* Ventral abdomen
* Dorsal midline
* Inguinal region
Mineralisation can also occur in the lungs and stomach
What does reduced collagen synthesis cause?
- Abnormal fibroblast function
- Fragile vessels
What does hyperadrenocorticism in cats cause?
- Skin fragility syndrome
- Thin skin
- Alopecia- unkept haircoat
- recurrent abscess
What is the pathogenesis of early castration in ferrets?
- Neutering/ Castration
- lack of testosterone/ oestradiol negative feedback on the hypothalamus
- incresae in GnRh
- Increase in LH level stimulating adrenla cortex LH receptors
- Hyperplasia and androgen production
- Adenoma/ Adenocarcinoma
What are the clinical signs of adrenal tumours in ferrets?
- Advanced age
- billateral symmetrical alopecia
- other lesions (pot-belly, comedones, swollen vulva)
What are the dermal signs of adrenal issues in guinea-pigs and hamsters
- Bilateral
- non-pruritic alopecia
- hyperpigmentation
Hyperoestrogenism is most often found in…
Middle aged dogs with oestrogen producing polycystic ovaries
and males with functional testicular tumours
What dermal lesions are found in dogs with adrenal issues?
- Symmetrical alopecia
- hyperpigmentation
- Enlarged nipples, vulva and mammary gland
What does hyperosetrogenism look like in guibea pigs?
Cysric ovarian disease causes billateral symmetrical flank alopecia
