Endocrine Flashcards
what is the general structure of the thyroid?
paired bilobed gland - right and left glands
where does the thyroid gland typically lie?
caudal to the larynx, between 5th and 8th tracheal rings
where is the thyroid in relation to the trachea?
ventrolateral to the trachea
right gland slightly more cranial than left
why is the thyroid at risk of haemorrhage during surgery?
very well vascularised
why is it important to be aware of iatrogenic damage during surgery on the thyroid?
there are numerous neurological structures in the area which require careful identification during surgery
where can ectopic thyroid tissue be found?
lying in the midline from the tongue to the abdomen
why is is possible to have ectopic thyroid tissue?
as a result of the path the thyroid tissue undergoes during embryonic development
why do we place oesophagostomy tubes on the lhs of the neck?
the oesophagus sits more on the lhs of the neck, in contact with the left thyroid gland
what is a functional thyroid condition?
one which produces thyroid hormones
how can we categorise surgical conditions of the thyroid?
functional vs non-functional
benign vs malignant neoplasia
when benign conditions can affect the thyroid gland?
adenoma
adenomatous hyperplasia
cysts
what malignancies can affect the thyroid gland?
carcinoma
adenocarcinoma
what type of benign thyroid masses affect dogs?
typically small and non-functional - rarely diagnosed
what type of benign thyroid masses affect cats?
typically functional and cause hyperthyroidism
what is the most common type of thyroid mass in cats?
95% of all cases are benign adenoma/adenomatous hyperplasia
are malignant thyroid masses in dogs typically functional?
no - mostly non-functional, do not cause hyperthyroidism and are instead presented due to the mass itself
are thyroid masses often malignant in cats?
no - typically functional, benign masses
do thyroid cysts occur commonly?
no - rare
what are the main pre-operative considerations for thyroidectomy?
body condition score
likelihood of metastasis
cardiovascular effects
renal effects
ocular effects
co-morbidities - typically older animals
degree of medical stabilisation achieved
what are the pre-op cardiovascular considerations for thyroidectomy?
tachycardia
hypertension
what are the pre-op renal considerations for thyroidectomy?
pre-renal azotemia
what are the pre-op ocular considerations for thyroidectomy?
retinal detachment secondary to hypertension
what are the pre-op c-morbidity considerations for thyroidectomy?
CVS, renal, increased GA risk, cachexia, arthritis
what is the benefit of medical stabilisation before thyroidectomy?
improvement of asa status