SA Endocrinology 1 - Canine Hypothyroidism Flashcards
How are thyroid hormones made?
Iodination of tyrosine residues of thryroglobulin
How do thyroid hormones circulate and which of these is the metabolically active state?
Protein bound state - reservoir
Free portion - metabolically active
How are thyroid hormones regulated?
Regulated via hypothalamic-pituiatry thyroid axis with negative feedback loops.
What is euthyroid sick syndrome?
Suppresses production of T4
Many sick patients will have measurably low T4 levels
Which two diseases cause canine hypothyroidism?
Immune mediated lymphocytic thyroiditis
Progressing to idiopathic atrophy
Which two breeds have a predisposition to canine hypothyroidism?
Doberman Pinscher
Golden Retriever
What is the most common group of signs associated with canine hypothyroidism?
Dermatological signs
When you should you test for canine hypothyroidism?
When you have clinical suspicion
What will 30% of dogs show on their haematology when diagnosed with canine hypothyroidism?
Mild, non-regenerative (normocytic, normochromic) anaemia (of chronic disease)
What is often seen of on the serum biochemistry of dogs with canine hypothyroidism?
Hyperlipaemia
Which test more accurately reflects thyroid function and which methodology should you use?
Utility of free T4
Need to use vaildates (equilibrium dialysis) methodology
When are thyroglobulin antibodies present in canine hypothyroidism?
During destructive phase
NOT when destruction is complete
Where breeds have a naturally low T4 value?
Greyhounds and sighthounds
List two drugs that will mimic hypothyroidism?
TMPS and phenobarbitone
Which drug should you use as a replacement in canine hypothyroidism?
Levothyroxine