Endocrinology Flashcards
What are the primary causes of hypothyroidism?
Atrophic hypothyroidism
Hashimotos thyroiditis
Iodine deficiency
What are secondary causes of hypothyroidism?
Drugs - lithium + amiodarone
Thyroidectomy
What abs may be seen in hypothyroidism?
Anit thyroid peroxidase abs TPO
What are some of the signs of hypothyroidism?
BRADYCARDIC
Reflexes down, ataxia, Dry skin, Yawning (tired), Cold peripheries, Ascites, Round puffy face, Depressed, Immobile +/- ileus, CCF
What are the 3 main causes of hyperthyroidism?
1) Graves disease
2) Toxic multi nodular goitre
3) Solitary toxic adenoma
What abs are associated with hyperthyroidism?
TSH receptor abs
What investigations can you do in hyperthyroidism?
T3, T3, TSH
TSH receptor abs
Thyroid USS
Radioisotope uptake scan
What are the medical options for treating hyperthyroidism?
- Symptomatic: BB - propranolol (stop the conversion of T4–>T3)
- Anti-thyroid: Carbimazole
- Propylthiouracil (for pregnancy or thyroid storm)
What are the SE of carbimazole?
Agranulocytosis + neutropenic sepsis as it causes myelosupression
Give a very brief pathophys behind graves disease
TSH receptor abs mimic TSH –> gland hyperplasia and high T3/T4
Give 4 signs specific to graves disease?
1) Ophthalmoplegia
2) Exopthalmos
3) Pretibial myxoedema
4) Thyroid acropathy
Give some causes of high serum prolactin levels
Benign pituitary adenoma
Hypothyroidism Cushings syndrome
Drugs: AP, Dopamine antagonists (domperidne and metoclopramide) and anti-depressants
At what levels do prolactin have to be to be a true prolactinoma?
> 5000
You suspect your patient has acromegaly, what investigation work up do you do?
- Bloods: BM, phosphate, calcium and triglycerides
- OGTT - glucose should decrease, if no response –> acromegaly
- Serum IGF -1 if normal that excludes acromegaly
- Serum GH (but it has episodic production)
- MRI pituitary and hypothalamus
Explain how the OGTT works to dx acromegaly
With acromegaly they have high GH levels
Hyperglycaemia should have a negative FB on GH and cause a decrease in GH levels
The patients are fasted and then given a glucose solution to drink. Their BM and GH levels are monitored every 30ms and the GH levels do not decrease with increased BMs in acromegaly
What are the medical and surgical treatment options for acromegaly?
M
- somatostatin analogues (inhibits GH) = ocretotide
- GH antagonists = pegvisokmant
S = Tran sphenoidal surgery
What is Cushing’s disease caused by?
Bilateral adrenal hyperplasia from an ACTH secreting pituitary adenoma
What tests can you do to dx someone with cushings syndrome?
1) dexamethasone suppression test (no suppression seen)
2) 24 hour urinary free cortisol
You have dx someone with Cushings syndrome - what do you look at next to determine the cause of the problem?
Drug chart - are the on exogenous steroids?
ACTH high - from the pituitary
- -> pituitary tumour = cushing’s disease
- -> ectopic = NSCLCa
ACTH low - from the adrenals
- ->pituitary adenoma
- -> pituitary carcinoma
What abs are seen in AI Addison’s?
21 hydroxylase Abs
How would a person with Addison’s present?
Thin - anorexia, N+V wt loss
Tanned - ACTH cross reacts with melanin
Tired - fatigue
Tumbling - weakness + faintness due to low BP
How do you dx someone with Addisons?
Short ACTH stimulation test = synactin test
Addisons if there is no increase in cortisol following the synactin (which is a chemical copy of ACTH)
Addisons can be excluded if cortisol levels increase >500
A 55 year old thin, tanned man presents with N + V, fever, muscle cramps and confusion
His ABG shows low sodium and glucose, high K+ and Cr.
What is happening and how do you treat it?
Addison's crisis Rx: IM/IV hydrocortisone 100mg if adult IV fluids (must rehydrate) Further hydrocortisone and glucose
What is Conns disease?
(Opposite of Addison’s)
= Primary hyperaldosteronism
Excessive production of aldosterone independent of RAAS system
Due to adrenal adenoma (80%) // bilateral adrenal hyperplasia
How would someone with Conns disease present?
Oedema, HTN,
Hypokalaemia - weakness, cramps, paraesthesia
Metabolic alkalosis (H low due to more K in urine)
Polyuria - inability to concentrate urine
What normal serum test would exclude Conns disease?
Renin
DD = renal artery stenosis // diuretics
How can you treat Conn’s?
M + S
M - aldosterone antagonist = spironolactone
S - laproscopic adrenalectomy
What can cause high potassium?
Renal causes - AKI/CKD, Addisons, renal tubular acidosis
Drugs - ACE-I, NSAIDs, heparin
Shift from IC–> EC = BB and DKA
Increased circulation - burns, tissue damage
What is phaeochromocytoma?
A rare catecholamine secreting tumour derived from the chromaffin cells in the adrenal medulla
How would someone with phaeochromocytoma present?
1) Headache
2) Sweating
3) Palpitations
4) Tremor
+ N, anxiety, C and wt loss
HTN
What investigations do you do for phaeochromocytoma?
Bloods - high: glucose, ca and Hb. Plasma metanephrines
Urine - 24hour free urine collection for Cr, total catecholamines and metanephrines
Imaging - Abdo CT
Give 2 differentials for phaeochromocytoma?
Multiple Endocrine Neoplasms (bilateral tumours)
Neurofibromatosis
How do you treat phaeochromocytoma?
Surgical resection of tumour in adrenal medulla
+ pre surgery alpha blockade
+ post surgery beta blockade
What are carcinoid tumours?
They are neuroendocrine tumours occurring in cells of the neuroendocrine system - occurs usually in the midgut
How do people with hypernatremia present?
FRIED Fever Restless Increased fluid retention + high BP oEdema Dry mouth and decreased UO
What are 4 ECG changes seen in hyperkalaemia?
P - no P waves
PR - Prolonged
QRS - Broad
T - Tall, tented
How do you treat hyperkalaemia?
1) Calcium gluconate 10% 10ml
2) Insulin (10u act rapid) with 50% 50ml dextrose
// 10mg salbutamol nebs
3) Calcium resonium 15-45mg
What are the ECG changes seen in hypokalaemia?
PRSTTU PR - long ST - depression T - inversion U - prominent (looks like a wavy baseline)
How do you treat hypokalaemia?
Mild + severe
Mild = SandoK
Severe = < 10mmol/hr K+ slowly
Need cardiac monitoring and regular bloods
Does DI cause hyper or hyponatraemia?
Hypernatraemia
You suspect someone has DI.
What investigation work up do you do?
Bloods: serum osmolality + U&Es
Urine: dip, 24hour urine collection, osmolality <300
Imaging: MRI pituitary + hypothalamus
ST: Water deprivation test with desmopressin response
What are some of the causes of hyponatraemia?
Low volume - D + V, diuretics
N volume - addison’s, SIADH, low thyroid
High volume - heart/liver/renal failure
What are some of the causes of SIADH?
Malignancy - SCLC, GI, GU
Drugs - SSRIs, Opiates
CNS disorders - infection, stroke, head injury, GBS, SLE
You have a patient who is euvolaemia hypotonic hyponatraemia and they have concentrated urine.
They are acutely unwell. How to you treat acute SIADH?
IV hypertonic saline (3%)
Furosemide
+ treat the cause
In patients who have hypercalcaemia, cinacalet can be used to reduce calcium. How does it do this?
Cinacalet is a calcimimetic. It acts on calcium receptors on chief cells in the parathyroid gland making them more sensitive to calcium levels. They are the main negative feedback regulator cells so reduce the amount of PTH produced and thus calcium
What investigation results would make you suspect DKA?
Hyperglycaemia >11
Ketones >3
Metabolic acidosis on ABG <7.3
What are the main causes of hyponatraemia?
Medical illnesses: HF, pneumonia, ca, MI \+ SALTED SIADH Age >70 Lower limb surgery Energy + nutrition Drugs - SSRIs, diuretics, PPI
How should you group the causes of hyponatraemia?
Hypovolaemic - V, D, diuretics
Euvolaemic - SIADH, addison’s, hypothyroidism
Hypervolaemic - Heart, liver & renal failure
What is the complication that the patient are at risk of if you hydrate them too quickly when they have hyponatraemia?
Pontine myelunolysis
