Smal Animal Medicine

Front 1

Describe the sequence of the HPT (hypothalamus, pituitary, thyroid) axis

Back 1

hypothalamus secretes TRH --> TRH stims pituitary to secrete TSH --> TSH stims thyroid to secrete T3 & T4 --> T3 & T4 have negative feedback on pituitary

Front 2

What percentage of the thyroid must be destroyed before you see c/s in primary hypothyroidism?

Back 2

75%

Front 3

What percentage of primary HOT (HypOThyroidism) is caused by lymphocytic thyroiditis?

what does lymphocytic thyroiditis cause?

Back 3

~50% of cases

leakage of thyroglobulin, fibrosis and inflammation

Front 4

What percentage of primary HOT is caused by idiopathic thyroid atrophy?

What type of tissue is it?

Back 4

~50%

adipose tissue

Front 5

Thyroid adenocarcinoma is often productive or nonproductive?

How does it cause hypothyroidism?

Back 5

nonproductive

if it destroys enough tissue --> hypothyroidism

Front 6

Secondary HOT is usually due to what?

Back 6

pituitary malformation/neoplasia

Front 7

1 HOT is due to the dysfunction of what?

2 HOT is due to the dysfunction of what?

3 is due to the dysfunction of what?

Back 7

1. thyroid

2. pituitary

3. hypothalamus

Front 8

Cretinism can be caused by what 3 things?

Back 8

congenital hypothyroidism
Iodine deficiency (rare)
thyroid dysgenesis/dyshormonogenesis (most common)

Front 9

Hypothyroidism is inherited by which 3 dog breeds?

Back 9

beagle, borzoi, old english sheepdogs

Front 10

What age, sex, and breed do you think of when thinking about HOT?

Back 10

middle aged, female, goldens

Front 11

What are some c/s seen with HOT?

Back 11

**weight gain
lethargy/mental dullness
dermatological signs (rat tail, deborrhea, etc)
**heat seeking/cold intolerance
bradycardia
constipation
muscle weakness/atrophy
edema
**Tragic expression
infertility
some opthalmologic signs (KCS, ulcers, glaucoma)
neuro signs (peripheral neuropathies, vestiburlar dz)
myxedema (rare)

Front 12

What is myxedema?

What does it feel/look like?

Back 12

hyaluronic acid deposition in eyelids, cheeks, and forehead

skin feels funky, slides, slimy-feeling

Front 13

What are some c/s of cretinism?

Back 13

mental retardation
stunted/disproportionate growth (delayed skeletal maturation, epiphyseal dysgenesis)
large broad heads
macroglossia
hypothermia
delated dental eruption
ataxia
abdominal distention
dermatologic signs

Front 14

Which breed is predisposed to cretinism?

Back 14

Giant Schnauzers

Front 15

What would you see on a CBC/Chemistry with HOT?

Back 15

mild non-regen anemia
fasting hypercholesterolemia (in 75% of patients)
hypertryglyceridemia

Front 16

Screening test(s) for HOT

Back 16

total T4

Front 17

Diagnostic test(s) for HOT

Back 17

Free T4
TSH

Front 18

What is the test of choice for dx of HOT?

In what order would you do the screening/diagnostic tests for HOT?

Back 18

fT4

tT4 is low, do a fT4

Front 19

What is a thyroglobulin autoantibody and what type of HOT is it seen in?

Back 19

antibody against the thyroglobulin seen in lymphocytic thyroiditis (Abs attack the thyroid itself

Front 20

What does it mean when a tT4 comes back in a elevated in a dog?

Back 20

The dog could have anti-T4 antibodies and is most likely hypothyroid

Front 21

What is euthyroid sick syndrome and what can cause it?

Back 21

where thyroid levels are decreased without an actual thyroid problem

systemic illness can decr T4
60% of dogs w/severe illness of any kind have low T4

Front 22

What do you do for a sick dog that comes back with a decr tT4?

Back 22

test fT4 (could be HOT or euthyroid sick syndrome)

Front 23

What meds do you use to treat HOT?

Back 23

L-thyroxine (normalized T3 and T4 and risk for hyperthyroidism is low)

Front 24

When using L-thyroxine, what types of improvement should you see when?

Back 24

1-2 weeks: improvement in activity
4-6 weeks: improvement in coat (neuro, cardio, hyperpigmentation may take months)

Front 25

When do you recheck treated HOT patients?

Back 25

recheck in 1 month if no abnormal signs beforehand, then recheck every 6 months

Front 26

What is the most common endocrine disorder in cats?

Back 26

hyperthyroidism (HET)

Front 27

is HET more often unilateral or bilateral?

Back 27

bilateral (70%)

Front 28

What causes HET?

Back 28

adenomatous hyperplasia/adenoma (most are benign)

Front 29

What is a common cause of feline HOT? In what breeds is it congenital?

Back 29

treatment of HET often causes HOT in cats

congenital in DSH and Abyssinians

Front 30

How does HET contribute to chronic kidney disease?

Back 30

it causes hypertension and increases GFR, sclerosis

Front 31

What are come c/s and physical exam findings you could see with HET?

Back 31

weight loss
PU/PD/polyphagia
v/d
hyperactivity, aggressive
weakness
dyspnea/panting (thyrotoxic cardiomyopathy)
blindness/retinal hemorrhage
palpable thyroid/thyroid slip
systolic murmur, tachycardia, gallop rhythm
unkempt appearance

Front 32

What would you see on a CBC/Chemistry in a cat w/HET?

Back 32

erythrocytosis
incr MCV
leukocytosis
lymphopenia
eosinopenia
elevated: ALT, ALP, LDH, AST, glucose, azotemia, Phos, Bili (almost always have elevated liver enzymes)

Front 33

If you find azotemia w/incr phosphorus, what two diseases in a cat would you think of?

Back 33

kidney disease or hyperthyroidism

Front 34

Why would you find an incr R wave and ventricular arrythmias on an ECG of a cat w/HET?

Back 34

bc HET causes thyrotoxic cardiomyopathy which looks the same as hypertrophic cardiomyopathy, and both cause a thickened/large left ventricle, which corresponds to the R wave in an ECG

Front 35

What test will diagnose HET in cats, but not HOT in dogs?

Back 35

tT4

Front 36

What is found on a normal pertechnetate scan? What can it be used for?

Back 36

normal: thyroid gland is 1:1 with salivary gland

can be used to find distant metastasis

Front 37

What 2 treatments are there for HET in cats? What can be used to treat the side effects (specifically cardiomyopathy)?

Back 37

anti-thyroid meds (methimazole, tapazole)
I-131 therapy
B-Blockers for cardiomyopathy

Front 38

How does methimazole work? is it reversible?

Back 38

blocks hormone synthesis and replease by preventing I incorporation and inhibiting coupling of DIT and MIT

reversible in 24-72 hrs

Front 39

What is the treatment of choice for HET?

Back 39

methimazole

Front 40

What is the one problem with transdermal methimazole?

when using methimazole, which is more important to test: CREA or USG?

Back 40

the effect changes over time - slows the cat's metabolism --> decr absorption of drug --> loses effect

USG bc it's the first to go

Front 41

Reversible side effects of methimazole

what do you do if these effects occur?

Back 41

anorexia, vomiting, lethargy

stop tx for a few days, then restart at a lower dose

Front 42

Irreversible side effects of methimazole

Back 42

facial excoriations, bleeding diathesis, hepatopathy, MG, cold agglutinin-like disease (blood clots @ lower temps, ear margins)

Front 43

What side effect could you find in cats on methimazole that you also find in lupus?

Back 43

+ANA (antinuclear antibodies)

Front 44

What would you hope to find during a methimazole trial and why?

Back 44

tT4 in the lower 1/2 of the range and a normal USG (does not guarantee absence of kidney disease)

Front 45

Obligate anaerobes:
Can't Breathe Air

Back 45

Clostridium
Bacteroides
Actinomyces
(lack catalase and/or superoxide dismutase; therefore, susceptible to oxidative damage)

Note: generally foul smelling (short-chain FAs), difficult to culture, and produce gas in tissue (CO2 and H2)

Front 46

What would you expect to see i the history and PE in a dog with thyroid neoplasia?

Back 46

**mass that bleeds w/FNA
dyspnea
dysphonia
dysphagia

(all bc there's a MASS in the throat region)