Endocrine Flashcards
Husband’s Endocrine Lectures
- Why is the owner bringing you this cat (Hx)?
- What are your findings on PE?
a. Ddx? - What are the cat’s CS?
b. Ddx? - What diagnostics will you run?
4a. Results?
c. Dx? - How will you Tx?
- This cat has lost weight, restless (meowing all the time), vomiting, eating a lot.
- Thin BCS, tachycardia, decr. wt., palpable thyroid, scruffy
a. Hyperthyroidism, DM, lymphoma - decr. weight, incr. appetite, vomiting, PU/PD
b. Hyperthyroidism, lymphoma, DM - MDB: CBC, Chem, UA, TT4
4a. CBC: incr. RBCs, Heinz bodies, mild stress leukogram
Chem: incr. liver enzy, azotemia, hyperphosphatemia, hyperglycemia
UA: low USG, proteinuria
TT4: elevated
c. Hyperthyroidism
5. depends on o $:
Medical tx:
Methimazole
Diet
Nuclear tx:
I131
Sx tx:
thyroidectomy
What can be a complication of hyperthyroidism tx?
Occult renal dz may be uncovered when thyroid is normalized!
What is most common cause of 1° hypothyroidism?
What species is it seen in?
lymphocytic thryoiditis
dogs
What are client’s CC for hypothyroid dogs?
lethargic
weight gain despite not eating that much
poor haircoat/not growing back after grooming
doesn’t have any oomph to play
likes to lie in the sun all day
What might your PE findings be on a hypothyroid dog?
skin changes:
symmetric alopecia
scaling
hyperpigmentation
pyoderma
incr. weight
tragic expression (myxedema)
What diagnostics might you run for a Ddx of hyperthyroidism?
What might the findings be?
CBC, Chem, UA, T4 & TSH
mild normocytic/chromic anemia
hypercholesterolemia
+/- incr. ALP
low T4, elevated TSH
What causes the disease Hypercalcemia?
Trick Question!!!!
Hypercalcemia is not a disease in an of itself!
It is a symptom of a disease!
How do you tx hypothyroidism in dogs?
How long is tx?
Oral supplementation w/ levothyroxine
Lifelong
What is HOGS IN YARD?
- H- hyperparathyroidism
- O- osteolysis
- G- granulomatous disease
- S- Spurious
- I- iatrogenic, idopathic (cats)
- N- neoplasia
- Y- youth
- A- Addison’s, acidemia
- R- renal disease (a or c)
- D- vit. D toxicosis
If a dog were to be dx’d with 1° hyperparathyroidism what age and breed might it be?
What is the most common tumor causing 1° hyperparathyroidism?
What would be the normal physiological response of PTH in the face of high iCa++?
Older & Keeshond!
Benign Functional Adenoma
PTH should be low to not stimulate the parathyroid. Even a value in normal range is not normal in the face of high iCa++
What are some causes of osteolytic dz that might cause hypercalcemia?
Osteomyelitis (bacterial or fungal)
Hypertrophic osteodystrophy
Good image to know
Remember: FT4 (unprotein bound in serum) is active → intracellularly → converted either into T3 (active) or rT3 (inactive)
What is euthyroid sick?
Non thyroidal illness causing a falsely decreased T4
What are thought to be the mechanisms behind euthyroid sickness?
decr. TSH release
change in protein binding
decr. synth of T4
other?
How should TT4 & TSH be interpreted when making dx of hypothyroidism?
Never dx only due to diagnostic testing!
TT4:
If in upper ½ of normal range → unlikely to have hypoT4
If low → either hypoT4 or euthyroid sick
If in lower ½ of normal range → may be hypoT4
TSH:
If high w/ a low TT4 or fT4→ 90% hypoT4
What CS can be seen with hypocalcemia?
At what level does total Ca have to be for CS of hypocalcemia? iCa++?
facial rubbing
seizure
lethargy
depression
coma
muscle tremors/cramping/fasciculations
Tot Ca: 6mg/dL iCa++: o.8mmol/L
CS of hyperCa?
PU/PD
Anorexia & Vomiting
Drowsiness
Weakness
What must be done when hypercalcemia is reflected on labwork?
Confirm incr. in Ca is due to ionizedCa!!
iCa++ test
thorough PE IMPERATIVE (digital rectal exam)
SYSTEMATICALLY RULE OUT CAUSES
HOGS IN YARD
What are most common hypercalcemic syndromes?
Neoplasia
1° hyperPTH
CKD (mild when present)
*HyperCa may result from kidney dz or cause kidney injury!
Hypoadrenocorticism (Addison’s)
