Endocrinology Flashcards
What are some surgical conditions of the thyroid?
Functional (producing thyroid hormones) / non-functional
Benign e.g. adenoma, adenomatous hyperplasia, cysts
Malignant neoplasia e.g. carcinoma, adenocarcinoma
Describe benign thyroid masses in dogs vs cats.
Dogs = typically small, non-functional, rarely diagnosed
Cats = typically functional, cause hyperthyroidism
What pre-op considerations should we have for thyroidectomy patients?
ASA status - systemic effects of hyperthyroidism, BCS/MCS
Metastasis?
CVS / renal / ocular / co-morbidities
Medical stabilisation
Complications
Describe a thyroidectomy.
Wide clip, dorsal recumbency
Ventral midline approach to neck
Unilateral / bilateral thyroidectomy +/- parathyroidectomy
Sometimes reimplanting parathyroid tissue will allow for neovascularisation
What complications of a thyroidectomy can we see?
Surgical technique and skill
Haemorrhage
Seroma formation
Laryngeal paralysis (if recurrent laryngeal nerves damaged)
Horners (damage to sympathetic trunk)
Hypocalcaemia - iatrogenic hypoparathyroidism
Recurrence
Describe the parathyroid.
2 pairs of parathyroid glands - intracapsular (caudal) and extracapsular (cranial)
Secrete PTH - increases blood calcium
What is primary hyperparathyroidism?
Parathyroid tumour produces excess PTH
Other parathyroid glands stop functioning normally - risk of hypocalcaemia post-op before they begin functioning again
How do we treat primary hyperparathyroidism?
Medical - ethanol injection/heat ablation
Parathyroidectomy
What pre-op considerations should we have for parathyroidectomy patients?
ASA status - systemic effects of hyperparathyroidism (hypercalcaemia), co-morbidities
Medical stabilisation e.g. diuresis, renal support
Complications
Describe a parathyroidectomy.
Wide clip, dorsal recumbency
Ventral midline approach to neck
Almost always going to remove one of four parathyroid glands
If intracapsular, likely to remove associated thyroid
What are some possible complications of parathyroidectomy?
Haemorrhage
Seroma formation
Laryngeal paralysis
Horners
Hypoparathyroidism - hypocalcaemia
What post-op care should we provide to parathyroidectomy patients?
IVFT
Analgesia - avoid NSAIDs
Monitor for complications - renal function, hypocalcaemia
Describe the risks of iatrogenic hypoparathyroidism associated with unilateral thyroidectomy.
Removes 1 of 2 thyroids
Removes 1 of 2 caudal parathyroids, but cranial may be damaged
Low risk hypocalcaemia
Low risk hypothyroidism
Describe the risks of iatrogenic hypoparathyroidism associated with bilateral thyroidectomy.
Removes 2 of 2 thyroids
Removes 2 of 2 parathyroids, but cranials may be damaged
Higher risk hypocalcaemia
High risk hypothyroidism
Describe the risks of iatrogenic hypoparathyroidism associated with unilateral parathyroidectomy.
Removes 1 of 2 thyroids
Removes 1 of 2 parathyroids, but cranials may be damaged/already suppressed
Highest risk hypocalcaemia
Low risk hypothyroidism
What are the clinical signs of iatrogenic hypoparathyroidism?
Within 2-3 days - inappetence, weakness/lethargy, ptyalism, pawing at face
Advanced - muscle fasciculation, tremors, tetany, seizures, coma/death
Only treat hypocalcaemia if clinical signs present!
How can we treat hypocalcaemia?
Oral vitamin D pre-op (takes 24-48hrs to have an effect)
Oral calcium (takes 1-3 days to work)
IV calcium - if clinical signs / VERY low blood calcium levels
Which pancreatic conditions are surgical?
Endocrine - insulinoma
Exocrine - exocrine pancreatic neoplasia
Pancreatic abscessation
Pancreatic cysts
Describe insulinomas.
Malignant carcinoma
Often metastasise to LNs and liver
What are the clinical signs of an insulinoma?
Lethargy
Tremors, seizures, collapse
Peripheral neuropathy
Extreme hypoglycaemia (<2mmol) in an upright dog!
How do we diagnose an insulinoma?
Bloods (insulin/glucose ratio)
Imaging
How do we manage insulinoma patients pre-op?
Feeding - q4-6hrs, diabetic food
Gentle, regular exercise
Manage hypoglycaemia - intervene if needed
How do we manage a hypoglycaemic crisis?
Give oral glucose first e.g. jam!
One-off IV glucose
Glucose infusion
Stop once start to improve
How do we carry out a partial pancreatectomy for an insulinoma?
Dextrose infusion throughout, glucose monitoring
Gentle technique to reduce pancreatitis risk
Small nodule <1cm in diameter, can be difficult to find!
Check liver for micrometastasis
What post-op care should we provide to insulinoma patients?
Feeding - as pre-op, +/- feeding tube
Exercise - as pre-op
Hypoglycaemia - if not normalising, indicates presence of missed micrometastasis
Drugs - IVFT, analgesia, steroids, chemo for residuals
What are the possible complications of insulinoma removal?
Persistent hypoglycaemia
Transient hyperglycaemia
Pancreatitis
Can develop Diabetes Mellitus
What are some adrenal gland surgical conditions?
Adrenal mass - benign/malignant, primary/secondary
Secondary adrenal enlargement (pituitary-dependent!)
What are the clinical signs of adrenal gland disease?
None
Functional - overproduction from cortex/medulla
Haemoabdomen
What are the clinical signs of overproduction from cortex in adrenal disease?
Conns syndrome - mineralcorticoids e.g. aldosterone
Cushings - glucocorticoids e.g. cortisol
Masculinising syndrome - androgen e.g. testosterone
What are the clinical signs of overproduction from medulla in adrenal disease?
Phaeochromocytoma - catecholamines e.g. norepinephrine/epinephrine (intermittent hypertension)
What pre-op considerations should we have for adrenalectomy patients?
Systemic effects e.g. hypokalaemia, endogenous steroid, excess adrenaline/noradrenaline
Co-morbidities
Medical stabilisation
Unilateral vs bilateral
How do we manage adrenalectomy patients peri-op?
Monitoring ECG for arrhythmias, BP, electrolytes
Drugs as needed
What are some possible intra-op complications with an adrenalectomy?
Tumour rupture
Haemorrhage
Tachycardia/arrhythmias - may need propranolol/lignocaine
Hyper/hypotension
May need supplementation of gluco/mineralocorticoids - dexamethasone, electrolytes
What post-op complications can we see with adrenalectomy patients?
Electrolyte abnormalities
Hyper/hypotension
Adrenal insufficiency - iatrogenic Addison’s
Delayed healing
Pulmonary thromboembolism
Describe feline hyperthyroidism.
Most common endocrine condition in cats, usually over 10yrs old
Benign tumour that secretes excess thyroid hormone (uni/bilateral)
Often concurrent disease e.g. HCM, CKD, hypertension
What are the clinical signs of feline hyperthyroidism?
Polyphagia
Weight loss
Tachycardia
Palpable enlarged thyroid gland
How do we treat feline hyperthyroidism?
Anti-thyroid drugs, iodine-restricted diet (lifelong)
Thyroidectomy
Radioactive iodine
What medications can be used to treat hyperthyroidism?
Drugs block synthesis of thyroid hormone
Methimazole / carbimazole
Normally euthyroid in 2-3 weeks
What are some common side effects of anti-thyroid drugs?
Vomiting, anorexia, lethargy
Usually minor and transient
What are some rare side effects of anti-thyroid drugs?
Persistent GI signs
Bone marrow suppression
Facial pruritis
Hepatopathy
What nursing considerations should we have for cats with hyperthyroidism?
Careful handling - often fractious, concurrent disease, consider gabapentin?
Senior cat clinics - look for clinical signs/measure T4 in bloods
Treatment monitoring every 3-12 months - bloods, urinalysis, BP
Describe dietary management for feline hyperthyroidism.
Iodine-restricted (iodine required to synthesis thyroid hormone)
Must be fed as sole food, lifelong
Can be euthyroid within 3 weeks
What causes canine hypothyroidism?
Destruction of thyroid tissue
Middle-aged dogs
How can we treat canine hypothyroidism?
Oral synthetic T4 - sodium levothyroxine
What nursing considerations should we have for dogs with hypothyroidism?
Weight management clinics and dermatological clinical signs
Treatment monitoring every 6-12 months (6-8 weeks after starting, 2-4 weeks after dose adjustment)
What hormones control calcium balance?
Parathyroid hormone - from parathyroid gland
Calcitriol (vitamin D) - from kidney
Calcitonin - from thyroid gland
What are the clinical signs of primary hyperparathyroidism?
Neuro - weakness, lethargy, exercise intolerance
GI - reduced appetite, nausea, vomiting, constipation
Urinary - PUPD, urolithiasis, UTI
CVS - hypertension, arrhythmias
How do we diagnose primary hyperparathyroidism?
Often elevated calcium is an incidental finding
High total calcium does not necessarily mean elevated ionised calcium
If elevated iCa then measure PTH
How can we treat primary hyperparathyroidism?
Most common and effective = surgery
OR ultrasound-guided glandular ablation by heat/ethanol injection
What can cause secondary hyperparathyroidism?
Chronically low calcium leading to elevated PTH
Renal failure
Nutritional - diet with little/no calcium or deficient in vitamin D
What can cause hypoparathyroidism?
Low or absent PTH despite low calcium
Surgical excision of parathyroid
Trauma, idiopathic, immune-mediated etc.
What are the clinical signs of hypoparathyroidism?
Seizures
Muscle fasciculations/twitching/cramping
Weakness, ataxia
Anorexia, vomiting
Facial rubbing
How do we diagnose hypoparathyroidism?
Measure iCa, phosphorous, PTH
How do we treat hypoparathyroidism with mild clinical signs?
Oral calcium supplements and calcitriol (vitamin D)
How do we treat severe life-threatening hypoparathyroidism?
IV calcium - bolus/CRI
Close monitoring essential (HR, ECG)
Administer slowly
Describe hyperadrenocorticism (Cushing’s disease).
Excess production of cortisol from adrenal gland
Mostly dogs, very rare in cats
Pituitary-dependent (PDH) vs adrenal-dependent (ADH)
Or iatrogenic (admin of glucocorticoids)
What are the clinical signs of hyperadrenocorticism?
PUPD, lethargy
Endocrine alopecia
Pot-belly, thin skin
Poor wound healing
Panting, polyphagia
Calcinosis cutis
How do we treat hyperadrenocorticism?
Trilostane (blocks synthesis of cortisol)
Suitable for PDH and ADH
Monitor - clinical signs and ACTH stim
Side effects uncommon - GI signs, iatrogenic hypoadrenocorticism, sudden death
What nursing considerations should we have for hyperadrenocorticism?
Senior clinics - look for clinical signs
Treatment monitoring (10 days after starting, then 4 weeks, 12 weeks then every 3 months)
Iatrogenic hypoadrenocorticism causing Addisonian crisis
Describe hypoadrenocorticism (Addison disease).
Lack of adrenal hormones (glucocorticoids and mineralocorticoids)
Young to middle-age dogs, rare in cats
Often vague, waxing and waning illness
What are the clinical signs of an Addisonian crisis?
Collapse
Hypotension
Weakness
Bradycardia
Severe dehydration and hypovolaemia
How do we diagnose hypoadrenocorticism?
Electrolyte abnormalities
ACTH stim test
How do we treat an Addisonian crisis?
Fluid resuscitation
Correct electrolytes - IV glucose and insulin if severe hyperkalaemia
Start ACTH stim ASAP
How do we treat hypoadrenocorticism long-term?
Glucocorticoid replacement (low dose prednisolone)
Mineralocorticoid replacement (Desoxycortone pivalate, injection every 4 weeks for life)
Describe pancreatitis.
Disease of exocrine pancreas
Inflammation of pancreas - idiopathic / dietary indiscretion, trauma, surgery
Pancreatic enzymes prematurely activated - start digesting pancreas
What are the clinical signs of mild pancreatitis?
Anorexia
Vomiting
Abdominal pain
Dehydration
Lethargy
What are the clinical signs of severe pancreatitis?
Generalised inflammation
DIC
Renal/multiorgan failure
Death
How can we treat pancreatitis?
Supportive care - IVFT, monitoring for systemic signs, analgesia
Nutritional support essential - anti-emetics, tube feeding, low fat highly digestible diet
Describe diabetes mellitus.
Failure of pancreas to produce insulin
Middle-aged to older, dogs and cats
Dogs require insulin injections, cats may not
What are the clinical signs of diabetes mellitus?
PUPD
Polyphagia and weight loss
Cataracts (dogs)
Peripheral neuropathy (cats)
Diabetic ketoacidosis (DKA) - vomiting, collapse, dehydration
Persistent hyperglycaemia
How do we treat diabetes mellitus in cats?
Insulin injections
Diet - low carb, high protein, calorie-controlled
Cats can go into diabetic remission - so monitor for hypoglycaemia!
How do we treat diabetes mellitus in dogs?
Insulin injections
Diet - high fibre high carb, calorie-controlled, consistent schedule
Exercise
What are the signs of hypoglycaemia?
Weakness, ataxia
Depression
Altered behaviour
Muscle twitching, seizures
What nursing considerations should we have for diabetic patients?
Must use correct syringes for type of insulin administered
Correct storage of insulin
BG measurements - take samples from same location
Consistency in lifestyle is key!
Extra care when undergoing GA