Endocrine Diseases Flashcards
Effects of insulin
Inhibits ketogenesis
Stimulates glucose uptake
Stimulates K+ uptake
What is the difference between type 1 and type 2 diabetes mellitus
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
Source of issues for type 1 diabetes
Pancreatectomy
Pancreatitis
Auto-immunity
Islet cell hypoplasia
Chemical toxicity
Source of issues for type 2 diabetes
Progesterone/agen
Growth hormone
Glucocorticoids
Glucagon
Catecholamines
Thyroid
Obesity
Aetiology of type 1 diabetes mellitus
Immune mediated - antibodies in circulation against Islet
Beta islet cell loss due to epi/pancreatitis
Congenital beta islet cell loss
Aetiology of type 2 diabetes mellitus
Progesterone - an acromegaly
Hyperadrenocorticism
Exogenous steroids
IGF1/GH excess
Pathophysiology of diabetes mellitus
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
Presentation of diabetes mellitus
Dull, depressed, weak, possibly comatose
Vomiting
Dehydrated
Common lab findings in diabetes mellitus
Urinalysis - glucosuria
Increased ALKP/ALT
Increased cholesterol/triglycerides
Fasting hyperglycemia
Can have hyponatraemia, ketonuria, ketonaemia
Diagnosis of diabetes mellitus
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)
Treatment for diabetes mellitus
Insulin - type and frequency
Diet
Body condition
Lifestyle
Spaying at appropriate time
Consider owner factors - finances/commitment etc
What are the 2 types of licensed insulin for dogs
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
Care factors for insulin
Must be kept 2-8°
Do not shake but roll
Beyond expiry can be ineffectual
Discard after 28 days use
Care with diet with diabetes mellitus
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
How do you start treating diabetes
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
Diabetes mellitus monitoring options
Owner at home
Blood glucose curves
Other
- fructosamine (aim for 400-450nmol/L)
- glycated haemoglobin (4-6% stabilized, 7%+ poorly stabilized)
Complications of diabetes mellitus
Hypoglycaemia
Hunger, food seeking, ataxia, weakness, collapse, convulsions
clinical signs of hyperthyroidism
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
what classes as a thyroid crisis
exaggerated thyrotoxicosis
severe tachycardia >300pbm
tachypnoea
panting
respiratory distress
profound weakness
ventro-flexion
sudden blindness
Tests for hyperthyroidism
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
treatment options for hyperthyroidism
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
reasons to perform scintigraphy
confirms hyperthyroid
excludes diagnosis in euthyroid cats
identifies disease pattern
identifies ectopic tissue
aids diagnosis of carcinoma
considerations for radioactive iodine
131I administered SC
can only be done with specific licensing/hospitalisation
cats become radioactive
anti-thyroid medication
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
ultra low iodine diet
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
Pathophysiology of diabetic ketoacidosis
reduced insulin = reduced cellular glucose uptake = metabolic deficit
glucagon…..acetoacetate and beta hydroxybutyrate are acidic leading to metabolic acidosis
history/CE for diabetic ketoacidosis
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
Diagnosis of diabetic ketoacidosis
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
treatment of diabetic ketoacidosis
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
hyperglycaemic, hyperosmolar syndrome
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
hyperadrenocorticism
80-90% are pituitary dependent - micro and macro adenomas/adenocarcinomas
10-20% adrenal dependent - adrenal adenomas/carcinomas
iatrogenic - steroids
canine hyperadrenocorticism
middle age/older dogs
female more common
PUPD
polyphagia
muscle wasting, weakness, pot belly, panting
skin thinning, calcinosis cutis, pigmentation, bruising, symmetrical hair loss
Hyperadrenocorticism diagnosis
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
hyperadrenocorticism endocrine tests
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
consideration for diabetics with HAC
treat DM first as cannot reply on usual markers in a diabetic
adrenal imaging for HAC
Pituitary dependent - symmetrical enlargement
adrenal dependent - one enlarged and one atrophied adrenal
HAC treatment
medial - trilostane is licensed, only works for 6-8 hours
surgical - adrenalectomy for ADH or hypophysectomy for PDH(very scarcely available)
SID HAC therapy
preserve mineralocorticoid function
allows some negative feedback to mitigate increases in pituitary ACTH output or enlargement
phaechromocytoma
can be confused for hyperadrenocorticism
dx - urinary catecholamine metabolities, histology post surgery
treatment - surgery, medical - adrenoreceptor antagonists, phenoxylbenzamine, propanolol.
normal calcium controls
many exchanges between gut, plasma, skeleton and kidneys
how is calcium distributed
between ionized, bound and complexed calcium
renal secondary hyperparathyroidism
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
hypercalcaemia causes
increased PTH activity -
activity of PTH like substances
increased vitaminD activity (drives calcium into circulation)
osetolysis - calcium from bone
other/unclear mechanism
causes of total hyperCa
dogs - malignancy, hyperadrenocorticism, primary hyperparathyroidism, CRF, vit D toxicosis, granulomatous disease
cats - idiopathic, renal failure, malignancy, primary hyperparathyroidism
HARDIONS/HOGSINYARD
idiopathic hypercalcaemia
young-middle aged cats
mild-moderate hypercalcaemia
no obvious atiology - hypercalcaemia, normal phosphorus, intact PTH, PTHrp undetectable, normal vitd3
investigations of hypercalcaemia
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
azotaemic hypercalcaemia
elevated urea,creatinine, tCa and phosphorus
which came first?
renal dysfunction - elevated total calcium
elevated calcium - renal dysfunction
parathyroid hormone + ionised calcium
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
25-hydroxy vitamin d
hydroxylation occurs in liver
great indication of dietary sufficiency
use for suspected cholecalciferol intoxification
rule out dietary misinformation
1,25 dihydroxy vitamin D
1a hydroxylation in renal tubules
lower with reduced renal tubular mass
in pathogenesis of secondary hyperparathyroidism
hypercalcaemia treatment
fluids/diuresis - 5ml/kg/hr NaCl
determine by Ca:P ratio
furosemide once hydrated
glucocorticoids - prednisolone 1mg/kg
bisphosphonates- stop calcium removal from bone
parathyroid adenoma
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
hypocalcaemia
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
what does fructosamine indicate
blood glucose over the last 1-3 weeks
not effected by stress
can be normal in mild or recent diabetics
