Endocrine Diseases

Question 1

Effects of insulin

Answer 1

Inhibits ketogenesis
Stimulates glucose uptake
Stimulates K+ uptake

Question 2

What is the difference between type 1 and type 2 diabetes mellitus

Answer 2

Type 1 - beta cell production leading to insulin deficiency. Immune mediated and idiopathic
Type 2 - ranges predominantly insulin resistance to a secretory defect with/without resistance

Question 3

Source of issues for type 1 diabetes

Answer 3

Pancreatectomy
Pancreatitis
Auto-immunity
Islet cell hypoplasia
Chemical toxicity

Question 4

Source of issues for type 2 diabetes

Answer 4

Progesterone/agen
Growth hormone
Glucocorticoids
Glucagon
Catecholamines
Thyroid
Obesity

Question 5

Aetiology of type 1 diabetes mellitus

Answer 5

Immune mediated - antibodies in circulation against Islet
Beta islet cell loss due to epi/pancreatitis
Congenital beta islet cell loss

Question 6

Aetiology of type 2 diabetes mellitus

Answer 6

Progesterone - an acromegaly
Hyperadrenocorticism
Exogenous steroids
IGF1/GH excess

Question 7

Pathophysiology of diabetes mellitus

Answer 7

Polyuria/polydipsia - osmotic diuresis
Polyphagia - insulin in cns stops the hypothalamic satiety centre
Weight loss/exercise intolerance/ lethargy due to NEB and reduced glucose and amino acid uptake
Recurrent infections - immunological compromise and favour of microbial growth
Ketotic breath
Cataracts due to osmosis

Question 8

Presentation of diabetes mellitus

Answer 8

Dull, depressed, weak, possibly comatose
Vomiting
Dehydrated

Question 9

Common lab findings in diabetes mellitus

Answer 9

Urinalysis - glucosuria
Increased ALKP/ALT
Increased cholesterol/triglycerides
Fasting hyperglycemia
Can have hyponatraemia, ketonuria, ketonaemia

Question 10

Diagnosis of diabetes mellitus

Answer 10

Hyperglycemia - fasting hyperglycemia. >12mmol/L usually, 5.5-12mmol/L more challenging diagnosis
Glucosuria - 10-12mmol/L
Ketonuria
Fructosaminev>400mmol/L highly suggestive of DM (false negatives possible)

Question 11

Treatment for diabetes mellitus

Answer 11

Insulin - type and frequency
Diet
Body condition
Lifestyle
Spaying at appropriate time
Consider owner factors - finances/commitment etc

Question 12

What are the 2 types of licensed insulin for dogs

Answer 12

Caninsulin - intermediate acting, usually twice daily, initially at 0.5ui/kg
Prozinc - protamine zinc insulin, BID in cats and SID in dogs. Most require 0.8-1.2iu/kg/dose to stabilize

Question 13

Care factors for insulin

Answer 13

Must be kept 2-8°
Do not shake but roll
Beyond expiry can be ineffectual
Discard after 28 days use

Question 14

Care with diet with diabetes mellitus

Answer 14

Consistent diet and timing important
Need to be high in complex carbohydrates to minimize glucose peaks
High fibre
Avoid semi moist foods
Need consistent exercise similarly

Question 15

How do you start treating diabetes

Answer 15

Start insulin giving 0.5 iu/kg SC bid
Make sure diet is correct/consistent
Get owner to monitor water intake
Re see in 7 days
If not controlled increase dose 10% and re check in 7 days

Question 16

Diabetes mellitus monitoring options

Answer 16

Owner at home
Blood glucose curves
Other
- fructosamine (aim for 400-450nmol/L)
- glycated haemoglobin (4-6% stabilized, 7%+ poorly stabilized)

Question 17

Complications of diabetes mellitus

Answer 17

Hypoglycaemia
Hunger, food seeking, ataxia, weakness, collapse, convulsions

Question 18

clinical signs of hyperthyroidism

Answer 18

goiter (98%)
increased appetite
vomiting
hyperactivity
weight loss
pu/pd
diarrhoea/increased faecal volume
muscle wasting
thin bcs
tachycardia >240
heart murmur
hypertension
agressive/reduced stress tolerance

Question 19

what classes as a thyroid crisis

Answer 19

exaggerated thyrotoxicosis
severe tachycardia >300pbm
tachypnoea
panting
respiratory distress
profound weakness
ventro-flexion
sudden blindness

Question 20

Tests for hyperthyroidism

Answer 20

specific
total t4 - increased in 90-05% hypert cats, will fluctuate and suppressed by non-thyroidal disease
free t4 - unbound, can diffuse into the cell, more sensitive. increased chance of false positive
t3 - active thyroid hormone, derived from t4 in extrathyroidal tissues
tsh - non thyroidal illness will affect
scintigraphy
non-specific
haematology/biochemistry for concurrent disease/secodnary hepatopahty
urinalysis - specific gravity, normally very high >1.035 and hyperthyrodism increases GFR

Question 21

treatment options for hyperthyroidism

Answer 21

radioactive iodine 131 - aim for euthyroid not hypo
surgery - most have bilateral disease. need to take care to lead blood supply to parathyroids or imbed in muscle.
anti-thyroid medication
ultra-low iodine diet

Question 22

reasons to perform scintigraphy

Answer 22

confirms hyperthyroid
excludes diagnosis in euthyroid cats
identifies disease pattern
identifies ectopic tissue
aids diagnosis of carcinoma

Question 23

considerations for radioactive iodine

Answer 23

131I administered SC
can only be done with specific licensing/hospitalisation
cats become radioactive

Question 24

anti-thyroid medication

Answer 24

carbimazole - prodrug or methimazole
stops incorporation of iodine into pre-thyroid proteins
reactions
- non-life-threatening - anorexia, vomiting, lethargy, face and neck excoriation
- life threatening - dyscrasia (leukaemia, anaemia, thrombocytopaenia) hepatopathy

Question 25

ultra low iodine diet

Answer 25

no iodine = no thyroid hormone produced
manages but does not cure disease
good when treatment not possible or with side effects to anti-thyroid med
issues - must be fed exclusively

Question 26

Pathophysiology of diabetic ketoacidosis

Answer 26

reduced insulin = reduced cellular glucose uptake = metabolic deficit
glucagon…..acetoacetate and beta hydroxybutyrate are acidic leading to metabolic acidosis

Question 27

history/CE for diabetic ketoacidosis

Answer 27

often new diabetic diagnosis, middle aged-older. PUPD not resolving, weight loss continuing. lethargy, anorexia and V+. often dehydrated/hypovolaemic
Abdo pain, hepatomegaly, reduced BCS, mental dullness

Question 28

Diagnosis of diabetic ketoacidosis

Answer 28

diabetes - hyperglycaemia/glucosuria
ketones - B-hydroxybutyrate, blood ketones ideals, urine tests
metabolic acidosis - blood gas machine for EPOC/iSTAT
anaemia/left shift neutrophilia common
elevated ALP/ALT
electrolyte derangements common

Question 29

treatment of diabetic ketoacidosis

Answer 29

hypovolaemia/dehydration - aggressive fluid therapy (hartmanns), monitor electrolytes(2-4hourly)
pseudo-hyperkalaemia - comes down a lot with fluid therapy
Hypophosphataemia - cri potassium phosphate
hyponatraemia
hypocalcaemia - fluid therapy
hypomagnemaesia - magnesium cri (indicated if vomiting over maropitant)
Hyperlgycaemia - measure once hydrated and control with insulin CRI
Condsider - analgesia, anti-emetics
Dogd - hyperadrenocorticism, pancreatitis, UTI
Cats - hepatic lipidosis, CRF, pancreatitis, bacterial/viral infection, neoplasia, acromegaly

Question 30

hyperglycaemic, hyperosmolar syndrome

Answer 30

rare but important
similar to DKA
hyperglycaemia-osmotic diuresis-haemoconcentration - hyperglycaemia
dx - BG>33.3mmol/l, absence of ketones
Treatment - fluid therapy over 24-48 hours, not quick as dont want osmotic gradient across BBB
max reduction <3mmol/l/h

Question 31

hyperadrenocorticism

Answer 31

80-90% are pituitary dependent - micro and macro adenomas/adenocarcinomas
10-20% adrenal dependent - adrenal adenomas/carcinomas
iatrogenic - steroids

Question 32

canine hyperadrenocorticism

Answer 32

middle age/older dogs
female more common
PUPD
polyphagia
muscle wasting, weakness, pot belly, panting
skin thinning, calcinosis cutis, pigmentation, bruising, symmetrical hair loss

Question 33

Hyperadrenocorticism diagnosis

Answer 33

radiography - hepatomegaly, pot belly, calcinosis cutis, distended bladder, tracheal/bronchial wall mineralisation, pulmonary metastasis, osteoporosis
haematology - stress leukogram (neutrophilia, lymphopaenia, monocytosis, absolute eosinopaenia) - question HAC diagnosis if any of these opposed
Biochemistry - increased ALP, ALT, hyperglycaemia, eleveated phosphorus, increased cholesterol/triglycerides
Urinalysis - <1.030 despite mild dehydration - above this HAC unlikely

Question 34

hyperadrenocorticism endocrine tests

Answer 34

low dose dexamethasone - dexamethasone given over 50% response = pituitary
acth response - give ACTH, at 1h >500-600nmol/l is positive. steroid therapy reduces response
urinary cortisol:creatinine ratio - urine samples - urine samples at home, unstressed
steroid induce alkaline phosphatase

Question 35

consideration for diabetics with HAC

Answer 35

treat DM first as cannot reply on usual markers in a diabetic

Question 36

adrenal imaging for HAC

Answer 36

Pituitary dependent - symmetrical enlargement
adrenal dependent - one enlarged and one atrophied adrenal

Question 37

HAC treatment

Answer 37

medial - trilostane is licensed, only works for 6-8 hours
surgical - adrenalectomy for ADH or hypophysectomy for PDH(very scarcely available)

Question 38

SID HAC therapy

Answer 38

preserve mineralocorticoid function
allows some negative feedback to mitigate increases in pituitary ACTH output or enlargement

Question 39

phaechromocytoma

Answer 39

can be confused for hyperadrenocorticism
dx - urinary catecholamine metabolities, histology post surgery
treatment - surgery, medical - adrenoreceptor antagonists, phenoxylbenzamine, propanolol.

Question 40

normal calcium controls

Answer 40

many exchanges between gut, plasma, skeleton and kidneys

Question 41

how is calcium distributed

Answer 41

between ionized, bound and complexed calcium

Question 42

renal secondary hyperparathyroidism

Answer 42

fgf-23, decreased calcitriol and reduced calcium absorption leads to increased PTH
hyperphosphataemia leads to increased complexed calcium
serum total calcium = normal-high
ionised low

Question 43

hypercalcaemia causes

Answer 43

increased PTH activity -
activity of PTH like substances
increased vitaminD activity (drives calcium into circulation)
osetolysis - calcium from bone
other/unclear mechanism

Question 44

causes of total hyperCa

Answer 44

dogs - malignancy, hyperadrenocorticism, primary hyperparathyroidism, CRF, vit D toxicosis, granulomatous disease
cats - idiopathic, renal failure, malignancy, primary hyperparathyroidism
HARDIONS/HOGSINYARD

Question 45

idiopathic hypercalcaemia

Answer 45

young-middle aged cats
mild-moderate hypercalcaemia
no obvious atiology - hypercalcaemia, normal phosphorus, intact PTH, PTHrp undetectable, normal vitd3

Question 46

investigations of hypercalcaemia

Answer 46

CS - PUPD, vomiting, anorexia, muscle weakness, dehydration
review history - diet supplements etc
breed - keeshond very common
clinical signs - lymph nodes, anal sac masses, neoplasias, parathyroid imaging, angiostrongylus, bloods

Question 47

azotaemic hypercalcaemia

Answer 47

elevated urea,creatinine, tCa and phosphorus
which came first?
renal dysfunction - elevated total calcium
elevated calcium - renal dysfunction

Question 48

parathyroid hormone + ionised calcium

Answer 48

serum pth+serum ionised calcium both low = primary hypoparathyroidism
high serum pth, low to normal ionised calcium - secondary hyperparathyroidism
low serum PTH and high ionised calcium - pth independent hypercalcaemia
high serum PTH, high ionised calcium - primary hyperparathyroidism

Question 49

25-hydroxy vitamin d

Answer 49

hydroxylation occurs in liver
great indication of dietary sufficiency
use for suspected cholecalciferol intoxification
rule out dietary misinformation

Question 50

1,25 dihydroxy vitamin D

Answer 50

1a hydroxylation in renal tubules
lower with reduced renal tubular mass
in pathogenesis of secondary hyperparathyroidism

Question 51

hypercalcaemia treatment

Answer 51

fluids/diuresis - 5ml/kg/hr NaCl
determine by Ca:P ratio
furosemide once hydrated
glucocorticoids - prednisolone 1mg/kg
bisphosphonates- stop calcium removal from bone

Question 52

parathyroid adenoma

Answer 52

hyperactive parathyroid will cause atrophy of the other glands
can very quickly lead to hypocalcaemia
monitor post surgery and support with calcium supplementation
aim for subclinical hypocalcaemia to stimulate remaining tissue

Question 53

hypocalcaemia

Answer 53

parathyroid dependent
demands exceeds supply/mobilisation eg periparturient tetany, nutritional deficiency, pancreatitis
clinical presentation - head rubbing, muscle fasiculations, stiff, ataxic, biting/licking at paws, agitated
dx - history/routine labs
tx - iv calcium, borogluconate etc, long term aim for low-normal hypocalcaemia

Question 54

what does fructosamine indicate

Answer 54

blood glucose over the last 1-3 weeks
not effected by stress
can be normal in mild or recent diabetics