Small Ani. Med- Canine symmetrical - bilateral alopecia 1 (Lecture 8)

drraythe's version from 2016-04-29 14:39


Question Answer
if the Pathogenesis of the alopecia is due to Folliculitis, the clinical appearance will be...Focal-multifocal alopecia
if the pathogenesis of the alopecia is due to Auto-induced (pruritus), the clinical appearance will be...Appears in the areas of pruritus Commonly broad & symmetric Associated with erythema and other lesions (lichenification)
*if the pathogenesis of the alopecia is due to Disturbance of hair growth, the clinical appearance will be..Symmetric non-pruritic alopecia Frequently on the trunk Slowly progressing
if the pathogenesis of the alopecia is due to Post-scarring, the clinical appearance will be...Localized, limited to areas of previous damage. Depigmentation common
Bilaterally symmetrical alopecia can be broken into what two categories?Endocrine disorders or Non-endocrine disorders
Bilaterally symmetrical alopecia --> *endocrine disorders--> what age does this usually affect? are there systemic signs?Middle-aged to old dogs. Systemic signs commonly present.
Bilaterally symmetrical alopecia --> *NON-endocrine disorders--> what age does this usually affect? are there systemic signs?Young animals, No systemic signs
does endocrine or non-endocrine causes of bilateral alopecia have breed dispositions?non-endocrine (makes sense, cause an endocrine disorder can happen to anyone...)
what are the 2 Hair cycle disturbances leading to bilateral symmetrical alopecia?(1) Telogenization (excessive, generalized) (resting stage of hair growth) (2) Follicular dysplasia


Question Answer
what is the cause of acquired primary hypothyroidism?autoimmune lymphocytic thyroiditis (> 90% cases), leading to the destruction of the thyroid parenchyma
which hair cycle disturbance is caused by hypothyroidism, and why?Low T4 levels leads to telogenization of hair follicles (arrest)
is there a breed disposition for acquired primary hypothyroidism?Any breed can be affected, more common in large breed dogs (Golden retrievers, Irish setters, Labrador retrievers)
is there an age disposition for hypothyroidism?Middle aged dogs (mean age= 6 years)
what are the CUTANEOUS signs of acquired primary hypothyroidism?Trunk/generalized scaling, Dry, brittle coat, Alopecia on the trunk, high friction areas, Relapsing pyoderma/folliculitis, Hyperpigmentation, Otitis externa (ceruminous or infectious), Facial myxedema (facies tragica) (Increased GAGs in dermis, H20 retention)
what is the fur coat like for acquire 1* hypothyroidism?dry and brittle
where do you usually see alopecia for acquired 1* hypothyroidism?Alopecia on the trunk, high friction areas
how might the skin be affected by acquired 1* hypothyroidism?scaling (trunk to generalized), Relapsing pyoderma/folliculitis, hyperpigmented
what other condition might happen bc of acquired 1* hypothyroidism?Otitis externa (ceruminous or infectious)
why do they get a "tragic face"?this is Facial myxedema, it is due to Increased GAGs in dermis, H20 retention
6 systemic signs of hypothyroidism?Lethargy, Weight gain (w/o eating more food), Hypothermia, Bradycardia, Cardiomyopathy, Neuromuscular disorders
how is body temp affected by hypothyroidism?hypothermia
how is the heart affected by hypothyroidism?bradycardia, cardiomyopathy
is the nervous system affected by hypothyroidism?Neuromuscular disorders
how does CBC look with hypothyroidism?Normochromic, normocytic, non-regenerative anemia, HCT: 25-36%
what is the chem panel like with hypothyroidism?Hypercholesterolemia in 75% of cases, Hypertriglyceridemia, Hyponatremia
*what is a big hint towards hypothyroidism pertaining to tests you can do?chem panel--> **Hypercholesterolemia
what are 2 thyroid function tests and what are their results with hypothryroidism? which thyroid fxn test is not useful in the dog?(1) Low T4 and fT4 (2) High TSH....... TT3 and fT3 considered unreliable in the dog
would you rather look at T4 of fT4 levels?fT4 correlates directly with availability to tissues, Less influenced by medication conditions and other drugs. Must measure by ED (equilibrium dialysis)
is it common to see high TSH in 1* hypothyroidism?75-80% in 1* hypothyroidism
what is Euthyroid sick syndrome?low serum T4 levels with normal thyroid function
5 common causes of Euthyroid sick syndrome?(low serum T4 levels with normal thyroid function) (1) Hyperadrenocorticism (2) Diabetes mellitus (3) Other systemic illnesses (4) Estrus, pregnancy (5) Medications (glucocorticoids, potentiated sulphonamides, phenobarbital, carprofen)
is it high or low adrenal fxn that can lead to euthyroid sick syndrome?Hyperadrenocorticism
two distinctly female things which can cause euthyroid sick syndrome?estrus and pregnancy
**4 medications which can cause euthyroid sick syndrome?glucocorticoids, potentiated sulphonamides, phenobarbital, carprofen (she said ppl forget about carprofen all the time)
how do you tx hypothyroidism? how do you check-in/reassess treatment? How do you know if you need to recheck sooner?L-thyroxine (T4): 0.01-0.02 mg/kg PO BID. After 4 weeks, 4-6 h post-pill T4 should be measured and the dose adjusted if needed. When stable, reevaluation q 6-12 months. Recheck sooner if clinical signs have not resolved, relapse, or thyrotoxicosis

Hyperadrenocorticism (Cushing’s disease, hyperglucocorticism)

Question Answer
what are the 2 types of hyperadrenocorticism which can lead to bilateral alopecia?(1) Spontaneous Cushing’s disease (2) Iatrogenic Cushing’s disease
Spontaneous Cushing’s disease is due to.... (2)(1) Bilateral adrenal hyperplasia due to pituitary adenoma (PDH) 85% of the cases (2) Adrenal adenoma/adenocarcinoma (AT) 15% of the cases
Iatrogenic Cushing’s disease is due to....Exogenous administration of glucocorticoids
Hyperadrenocorticism--> sex predilection? Age? breed?No sex predilections. Majority of dogs > 8 years of age. Many breed predilections: Poodle, English bulldog, Boston terrier, boxer, beagle, Dachshund, small breed dogs
Cutaneous signs of Hyperadrenocorticism (6)(1) progressive, bilateral symmetric alopecia affecting the trunk (2) cutaneous atrophy (3) comedones (4) hyperpigmented macules (5) calcinosis cutis (6) adult-onset demodicosis
what other dz might come about because of hyperadrenocorticism?adult onset demodicosis!!!
how is thickness of skin affected by hyperAC?cutaneous atrophy (pic: so you can see BVs really well)
where does alopecia tend to be with HyperAC?progressive, bilateral symmetric alopecia affecting the trunk
what are two primary skin lesions you see with hyperAC?comedones and hyperpigmented macules
what deposition dz can be seen with hyperAC?calcinosis cutis
systemic signs from HyperAC? (6)(1) PU/PD, polyphagia (2) pendulous abdomen (3) hepatomegaly (4) muscle atrophy (5) panting (6) anestrus
how is the female cycle affected by hyperAC?anestrus
how is the dogs shape affected by hyperAC?pendulous abdomen bc mm atrophy and hepatomegaly
what is a possible classic appearance of skin lesions with hyperAC?classic appearance is salmon colored appearance with lots of inflammation around the edges
what does CBC look like with cushings?Stress leukogram + Thrombocytosis + Polycythemia (HCT: 45-55%)
what are Serum biochemistry abnormalities you'd see with cushing's?***inc ALP (80%), inc ALT~, Hypercholesterolemia (the major marker for hypothyroid, so look out), Mild hyperglycemia (DM in 5-10% cases)
*what is a big hint towards cushings pertaining to tests you can do?chem panel--> ***inc ALP (80%), inc ALT~ (bc dont see this one with hypothyroid, whereas there is crossover with hypercholesterol)
how is urine affected by cushings?Hyposthenuria - USG <1.015, proteinuria
what is the Screening test you use to start to dx cushings? what should you know about the efficacy of this test?Urine cortisol:creatinine test. Must know this test has very low specificity (specificity is trust the positive, so if low, in this case, not awesome positives so gotta move to next test) If negative, 99% ruled out Cushing’s. If positive, proceed to next test
3 main diagnosis tests for cushings?(1) Urine cortisol:creatinine (the screening test-- low specificity) (2) ACTH stimulation test (inc specificity) (3) Low Dose Dexamethasone Suppression test (inc sensitivity)
ACTH stimulation test--> what can this test tell you, and what can you use this test to do?Can differentiate between iatrogenic and spontaneous Cushing’s and to monitor response to treatment
aside from the 3 main diagnostic tests for cushings, what are some other tests you can do which can help aid in diagnosis?Ultrasound evaluation of both adrenal glands (size and morphology), High dose dexamethasone suppression test, CT and MRI of the pituitary gland, Basal ACTH level (available only in a few labs in the world)
what is the most common cause of cushings in cats?80% PDH ( pituitary adenoma)
how does cushing's usually present in cats? (clinical signs)Vague clinical signs, Diabetes mellitus, Skin fragility, Curling of the pinnal tips
how do you treat cushing's if it is caused by PDH (pituitary adenoma)? (4)(1) Trilostane*** (2) o,p’-DDD (mitotane)*** (3) Radiotherapy (macroadenomas) (4) Surgical excision (transsphenoidal hypophysectomy)
how do you treat cushing's if it is caused by Adrenal neoplasia? (2)(1) Surgical adrenalectomy (2) o,p’-DDD (mitotane), trilostane
how do you treat the calcinosis cutis caused by the cushings? what must you try to do before starting to treat this?obv you should try to solve the cushings first or this will keep happening. Use DMSO to dissolve calcium deposits (it also acts as an anti-inflammatory). (Minocycline?)

Sertoli cell tumour

Question Answer
who does Sertoli cell tumour affect? who is more prone? where is the tumor? Why does it cause alopecia?Testicular neoplasm, so it affects Intact males. More common in cryptorchid dogs. Excess estrogen secreted by tumour cells--> alopecia
3 major clinical signs of a sertoli cell tumor?(1) Asymmetrical testicles on palpation (enlargement and atrophy) (2) Prostatomegaly / prostatitis (3) Feminization (Gynecomastia, Pendulous prepuce)
Dermatologic signs of sertoli cell tumor? (6)(1) Bilaterally symmetrical alopecia (2) Primary hair follicles of the cervical region, trunk, perianal skin and posterior thighs are most sensitive to estrogen levels (3) Absence of pruritus (4) Hyperpigmentation (5) Otitis externa (6) Comedones
which locations' hair follicles are most sensitive to estrogen (thus, the distribution of alopecia...?)Primary hair follicles of the cervical region, trunk, perianal skin and posterior thighs
does sertoli cell tumor--> hyperestrogenism cause pruritus?no
what other dz/problem can come about because of hyperestrogenism?Otitis externa
what lesions aside from alopecia might you see on the skin bc sertoli tumor--> hyperE?Hyperpigmentation, Comedones
what are other (non skin) clinical signs you can see with sertoli tumor--> hyperE?Mental dullness, Anemia, Thrombocytopenia, Bone marrow suppression, Attractiveness to other male dogs (things associated with hyperE, basically)
how do you dx sertoli cell tumor?Physical + dermatologic examination and Ultrasound (testicles / abdomen)
how do you sx sertoli cell tumor? whats the prog?tx with castration, good prog

alopecia X

Question Answer
what is the pathogenesis of alopeca X?Pathogenesis not characterized (affects certain breeds tho so maybe a genetic thing)
breed disposition for alopecia X? Sex predilection?Affects plush-coated breeds like Pomerian (coat funk / black skin dz), Mini Poodles, Malamutes. males more affected than females
average age of onset for alopecia X?4 yrs
Distribution of alopecia in alopecia X?Alopecia circumferentially around cervical region (under the collar), rat tail, truncal. Head and extremities are spared!!!
clinical signs of alopecia X?Bilateral symmetrical alopecia, Hyperpigmentation, No systemic illness
is there systemic illness with alopecia X?nope...basically just alopecia and some hyperpigmentation
2 ways to dx alopecia X?(1) Rule out hypothyroidism and Cushing’s (2) Biopsy: flame follicles! (Excessive tricholemmal keratinization of hair follicles)
what is an identifying feature histopathologically which helps you dx alopecia X? explain what is going on with thislook for flame follicles which is Excessive tricholemmal keratinization of hair follicles
how do you tx alopecia X?Not needed! This is a cosmetic disease (sweater therapy- ie put clothes on the dog to cover its bald spots). If intact, castration (might make a diff?). Can attempt Trilostane, Melatonin at 3mg/dog BID