Endocrinology Flashcards
(150 cards)
How reproducible is the OGTT
65%
How often to have HbA1Cs for
1) diagnosis
2) monitoring
MBS rebats:
1) every 12 months for diagnosis
2) 4 times/year for established diabetes
Factors that alter HbA1C
1) erythropoiesis: lower erythropoiesis = increased HbA1C and increased erythropoiesis (e.g. EPO administration) = decreased HbA1C
2) Altered Hb - haemoglobinopathies
3) Glycation - ETOH, CKD increased HbA1C, aspirin, vit C decreased HbA1C
4) Erythrocyte destruction - splenectomies increase HbA1C, things that decrease erythrocyte lifespans (splenomegaly) decrease HbA1C
5) Things that affect the assay: Bilirubin, triglycerides
What’s Whipple’s Triad
3 clinic criteria that suggests the non diabetic patient’s symptoms may result from an insulinoma.
1) Symptoms known or likely to be caused by hypoglycemia especially after fasting or heavy exercise
2) A low plasma glucose measured at the time of the symptoms
3) Relief of symptoms when the glucose level is raised
What investigations to do for hypoglycaemia in a non diabetic?
Insulin
C-peptide
What is C-peptide
A byproduct of insulin production. It is a good marker of insulin production.
When to avoid contrast in thyroid disease
Multinodular goitre, suppressed TSH, thyrotoxicosis history
What is C-peptide
A byproduct of insulin production. It is a good marker of insulin production.
When to avoid contrast in thyroid disease
Multinodular goitre, suppressed TSH, thyrotoxicosis history
1st investigation after finding a thyroid nodule clinically
TSH
Thyroid nodule and TSH not suppressed
Fine-needle aspiration biopsy
Are malignant thyroid nodules taller or wider
taller
Adrenal incidentoloma <10 HFU and <4cm
Check functional status – ARR – 24h Urinary Catecholamines – 1 mg Dexamethasone suppression test • Repeat adrenal CT scan in 6 months • Then annual CT scans for 1-2 years • Hormone re-evaluation annually for 5 years
Antihypertensives that do not affect ARR
verapamil, prazosin, hydralazine, moxonidine
Antihypertensives that do not affect ARR
verapamil, prazosin, hydralazine, moxonidine
What effects would ACE I have on renin?
Increase renin
What effects would ACE I have on renin?
Increase renin
How frequently to monitor for pituitary microadenomas (<1cm)
Re-scan in 12 months; annual scans for 3 years
Next investigation for androgen deficiency
LH/FSH
To work out if it’s a testicular (high LH/FSH) or hypothalamo-pituitary (low LH/FSH)
What does prolactinomas do to androgen levels?
It suppresses LH and FSH and hence suppresses androgen production
Criteria for striae that discriminates Cushings syndrome from the normal population
Reddish purple and 1cm wide
Screening test positive for Cushing’s Syndrome - what next
ACTH - to see if the hypercortisolism is ACTH dependent or not
ACTH independent suggests adrenal source
Cushing’s Syndrome + high ACTH - what next
High dose dexamethasone suppression tests - suppresses cortisol in Cushing’s Disease patients (temporarily) but not ectopic ACTH producing tumours
OR
Bilateral inferior petrosal sinus sampling - ratio of central to peripheral ACTH of more than 2 in the basal state or more than 3 after CRH stimulation is consistent with Cushing’s disease
DKA criteria
Hyperglycaemia (serum glucose >14)
Ketosis
pH <7.3 (bicarb <20 mmol/l)