Endocrine Flashcards
What causes a primary adrenal insufficiency? (5)
Adrenal gland affected: Addison's disease Malignancy e.g. adrenal mets, lymphoma Infection e.g. TB, HIV Adrenal haemorrhage Congenital adrenal hyperplasia
What causes a secondary adrenal insufficiency?
Pituitary gland dysfunction e.g. radiation, Sheehan syndrome
What causes a tertiary adrenal insufficiency?
Hypothalamus gland dysfunction e.g. long-term steroids suppresses activity
What signs are present in Addison’s disease? (2)
Hyperpigmentation
Postural hypotension
What special test do you use to diagnose Addison’s disease?
Short Synacthen test (ACTH stimulation test)
What blood tests are required to investigate Addison’s (apart from FBC, LFTs, U&Es)? (6)
Cortisol ACTH (differentiates between primary and secondary) Renin (high) and aldosterone (low) Adrenal autoantibodies Glucose
What electrolyte abnormalities would you expect in Addison’s? (5)
Low sodium and raised potassium
Other: low calcium and glucose, raised urea
What is the management of an Addisonian crisis?
Hydrocortisone 100mg STAT then every 6h
Monitor fluid balance
Monitor U&Es, glucose and ECG
What are the main pituitary dependent causes of Cushing’s? (2)
Cushing’s disease (pituitary adenoma)
Ectopic production e.g. SCLC producing ACTH
In these cases, the rise in cortisol is due to increase in ACTH; therefore will have raised ACTH in bloods
What are the main pituitary independent causes of Cushing’s?
Iatrogenic i.e. taking steroids - ACTH will be decreased due to negative feedback
Adrenal adenoma - cortisol production no longer listens to ACTH
In these cases, the ACTH will be low due to negative feedback; therefore will have low ACTH in bloods
What special test diagnoses Cushing’s syndrome?
Dexamethasone suppression test
If suppressed on 1mg dexamethasone, rules out dexamethasone
Then give 8mg
What is a probable diagnosis?
- High dose dexamethasone - cortisol suppressed, ACTH raised
- High dose dexamethasone - cortisol, not suppressed, ACTH raised
- High dose dexamethasone - cortisol, not suppressed, ACTH low
- Pituitary adenoma (Cushing’s disease)
- Ectopic ACTH
- Adrenal adenoma
What would you expect to see on an ABG for Cushing’s syndrome?
Hypokalaemic metabolic alkalosis
This is because an excess of mineralcorticoids causes sodium to be retained (causing hypertension) and potassium and hydrogen to be lost (K+ and H+ have same transporter)
So you’ve successfully diagnosed Cushing’s syndrome, now how would you find the culprit?
- Suspecting pituitary adenoma
- Suspecting ectopic or adrenal adenoma
- MRI of pituitary and bilateral inferior petrosal sinus sampling (IPSS)
- CT TAP
What are the causes of primary hyperaldosteronism?
Conn’s syndrome (adenoma), bilateral adrenal hyperplasia
What are the causes of secondary hyperaldosteronism?
Anything that raises renin e.g. renal artery stenosis, renin-secreting tumour, fibromuscular dysplasia, coarctation of aorta, diuretics
What is hyperaldosteronism most likely to present with?
Hypertension
What would you likely see on an ABG in hyperaldosteronism?
Hypokalaemic metabolic alkalosis
What special test is used in hyperaldosteronism?
Aldosterone-renin ratio
What is the medical management of hyperaldosteronism?
K+ sparing diuretics e.g. spironolactone, eplerenone
What are some secondary causes of diabetes?
Pancreatic disease e.g. chronic pancreatitis, cystic fibrosis, haemochromatosis
Endocrine e.g. Cushing’s, thyrotoxicosis, acromegaly
Medication e.g. steroids, atypical antipsychotics, thiazide diuretics
What is the diagnostic criteria for diabetes, assuming they have symptoms? (3)
Random blood glucose >11.1
Fasting glucose >7.0
HbA1c >48 (not suitable for type 1 or secondary cause)
If no symptoms, need 2 tests on different days to diagnose
What is the diagnostic criteria for impaired glucose tolerance?
Fasting glucose 6.1-6.9 AND 2h post glucose >7.8, <11.1
HbA1c 42-47
What initial bloods would you get when investigating diabetes (apart from glucose)?
U&Es, eGFR, urine ACR
Full lipid profile, HbA1c
TFTs, coeliac screen
What tests can you order if you are not sure if it is type 1 or type 2 diabetes? (2)
C-peptide and autoantibodies (e.g. anti-GAD, IAA)
Can you name the type of diabetic drug and the common side effects?
- Metformin
- Sitagliptin
- Exanetide
- Gliclazide
- Dapagliflozin
- Pioglitazone
- Biguanide - diarrhoea, nausea, lactic acidosis
- DDP-4 inhibitor - GI upset, pancreatitis
- GLP-1 mimetic - GI upset, asthenia, NB women must be on effective contraception
- Sulfonylurea - weight gain, hypoglycaemia
- SGLT-2 inhibitors - UTIs, weight loss
- Thiazolidinediones - weight gain, fluid retention, bladder cancer, osteoporosis, heart failure
Which of the type 2 medications is not used for dual therapy and when is it used?
Exanetide - only used if BMI >35 and insulin contraindicated
What is the management for hypoglycaemia?
If alert, can give glucose orally e.g. glucogel, sugar lumps, Lucozade and cola
If cannot take orally, give IV glucose 20% in a large vein or IM glucagon
What is the management for DKA? (7)
F - fluids
I - rapid acting insulin, fixed rate 0.1U/kg/h
G - closely monitor, give 10% dextrose after if falls below 14
P - monitor potassium
I - infection and other triggers (look for them)
C - chart fluid balance
K - ketones (monitor hourly)
When in doubt, follow the local DKA protocol!
What are the stages of diabetic retinopathy? (3)
- Background - microaneurysms and hard exudates
- Pre-proliferative - cotton wool spots, dot and blot haemorrhages
- Proliferative - symptomatic e.g. floaters or sudden vision loss; at risk of vitreous haemorrhage
What are the driving rules for type 1 diabetes? (4)
Must notify the DVLA
Carry glucose with you
Check BM before driving and every 2h - must be at least 5mmol
If BM low, stop, eat something sugary and wait 45 minutes
What special test is used for SIADH and what results would confirm it?
Urine and serum osmolality (and urine and serum Na+)
urine osmolality and sodium - high
serum osmolality and sodium - low
What are some causes of SIADH?
Small cell lung cancer Infection e.g. atypical pneumonia Abscess Drugse.g. lithium, carbemazepine, NSAIDs, antipsychotics Head injury
Hypothyroidism
Postoperative
What other blood tests would you order when investigating SIADH?
TFTs (exclude hypothyroidism)
K+ and possibly short Synacthen test (exclude Addison’s)
What is the special test for diabetes insipidus?
Fluid deprivation test
What do these results from the water deprivation test suggest?
- Before <300, after DDVAP >800
- Before <300, after <300
- Before >800, after >800
Cranial (as back to normal after giving ADH)
Nephrogenic (not due to lack of ADH)
Psychogenic or primary polydipsia
What are some causes of diabetes insipidus?
Cranial - tumour, infection, haemorrhage, Wolfram’s
Nephrogenic - hypokalaemia, hypercalcaemia, CKD, RTA, pregnancy, medication e.g. orlistat, lithium, congenital
What is the management for SIADH?
Consult a specialist before commencing treatment
Consider cause
Usually fluid restrict or give tolvaptan
What autoantibody is used to test for:
- Hashimoto’s?
- Grave’s?
- Thyroid peroxidase antibody (TPOAb)
2. Thyroid stimulating hormone receptor antibody (TRAb)
What are some causes of hyperthyroidism? (4)
Grave’s disease
Toxic multinodular goitre
Solitary nodule
De Quervain’s thyroiditis
What scans can you get to investigate a thyroid nodule? (2)
Thyroid USS
Thyroid uptake scan (high uptake in hyperthyroidism, low in cancer)
What are the most important side effects of carbimazole and propythiouracil? (2)
Agranulocytosis
Foetal abnormalities
What are the management options for hyperthyroidism? (3)
Medication e.g. beta blocker for symptoms, PTU, carbimazole
Surgery
Radioiodine
What are some causes of hypothyroidism? (5)
Hashimoto's Iodine deficiency Infiltration e.g. sarcoidosis, amyloidosis, haemochromatosis Medication e.g. amiodarone, lithium Pituitary failure e.g. Sheehan
What is the most common type of thyroid cancer?
Papillary thyroid carcinoma
What type of thyroid cancer arises from the C-cells?
Medullary thyroid carcinoma
