Endocrinology

Question 1

What are the causes of hypothyroidism?

Answer 1

Hashimoto’s (elevated anti-TPO), iodine deficiency, amiodarone, lithium, 2nd phase of thyroiditis.

Question 2

How is thyroxine dosed?

Answer 2

Full: 1.6micro/kg, partial: 25-50microg daily. Recheck 4-8 weekly. Aim 0.5-2.5 in most, more lax in elderly. High dose risks loss of bone mass, AF, cardiac ischaemia.

Question 3

How is thyroxine taken?

Answer 3

Stored in fridge, empty stomach 30-60min before food or 2h post. Calcium, iron and bile resin interfere w absorption.

Question 4

What are 3 thyroid antibodies and when are they used?

Answer 4

Anti-TPO present in most cases of hashimoto’s. Anti-thyroglobulin used in post cancer followup, can be in normal people. TSH receptor antibodies in graves disease (can have graves without it).

Thyroid stimulating immunoglobulin seen in graves

Question 5

How is subclinical hypothyroidism managed?

Answer 5

Try treating if symptomatic. If TSH >10, repeat in 4-8 weeks. If TSH < 10 retest, check TPO and monitor 6-12mo.

Question 6

What are the causes of hyperthyroidism?

Answer 6

Graves disease (diffuse goitre), toxic multinodular goitre or adenoma, painless post partum thyroiditis, painful subacute thyroiditis (post URTI), amiodarone use, factitious ingestion

Question 7

What tests are indicated for hyperthyroidism?

Answer 7

TSH R ab and thyroid stimulating immunoglobulin for graves. If not obvious graves, do scintigraphy with tech-99 (C/I in pregnancy), for nodules/adenoma or diffuse uptake.

Question 8

How is hyperthyroidism managed? Options, risks.

Answer 8

Endo review. Carbimazole + PTU for graves, adenoma. Risk agranulocytosis, PTU can affect liver. Use T3/4 to monitor. Symptom treatment: beta blockers for thyroiditis and may need thyroxine later. Iodine/surgery for severe/recurrent, MNG, cancer.

Question 9

What is the workup for a thyroid nodule?

Answer 9

TSH first. If hypo, treat w thyroxine as may regress. If normal, do U/S for cancer. If hyper, do scintigraphy to see if hot nodule or graves or cold which needs U/S. Check lymph nodes and Fhx, U/S features guide F/U and aspiration.

Question 10

How is hypo/hyperthyroidism managed in pregnancy?

Answer 10

Hypo risks miscarriage, low weight, neurodevelopment. Lower target TSH, increase thyroxine 25-30% at 6/40, monitor 4-6 weekly. If new hypo, refer and may need urgent treatment. Hyper generally ok -bHCG stimulates TSH receptor, treat if graves or severe.

Question 11

What are general and medical risk factors for osteoporosis?

Answer 11

Smoking, alcohol, Fhx, Vit D deficiency, low calcium intake, sedentary lifestyle, early menopause, late menarche. Hyperthyroid, hyperparathyroid, RA, coeliac, CKD, liver disease, Diabetes, steroids (7.5mg 3mo), excess thyroxine, antiandrogens.

Question 12

How is osteoporosis diagnosed? When is medication indicated?

Answer 12

T score < -2.5 (compared to healthy 30yo) OR >50yo with min trauma hip/vertebral fracture; OR 50yo min trauma fracture w T score <-1.5. OR 10 year risk of fracture elevated.

<-1.0 is osteopaenia

Question 13

What is the non-pharm management of osteoporosis?

Answer 13

Falls risk and reduction strategies, Vit D if low or risk, 1300mg Ca daily (500-600mg supplement is diet poor), weight bearing impact loading exercise, balance training, avoid twisting if vertebral. Aim BMI 18-25.

Question 14

How is prolia used in osteoporosis?

Answer 14

Denosumab 6mo injection, if missed risk spontaneous vertebral fracture. Check Vit D, Ca and CrCl >30 before 1st/every dose, risk hypocalcaemia. Increase turnover when stopped, can swap to alendronate if stopping.

Use >10y hasn’t been studied. Small risk of ONJ

Question 15

How are bisphosphonates used in osteoporosis?

Answer 15

Effects persist, avoid GFR < 35. Alendroate daily/weekly, risedronate weekly/monthly oral, empty stomach, use 5y min. Zoledronic acid IV yearly, use 3y min. Double use if high risk (>75, hip/spine fractures, fracture on treatment)

Question 16

What are the side effects of bisphosphonates? What are 2nd line options?

Answer 16

Oral: upper GI irritation (GORD, PUD), affected by Ca, iron. Zoledronic acid: transient flu like symptoms, uveitis, hypocalcaemia. Long term: ONJ, atypical femur fracture. ONJ rare, dental review before starting, usually safe in first 6mo. 2nd line: raloxifene (SERM), tibolone, HRT.

Question 17

What is addison’s disease - symptoms, diagnosis.

Answer 17

Adrenal insufficiency - fatigue, weight loss, postural hypotension. High K, low Na. Hyperpigmentation, vitilgo, hair loss. Short synacthen test (also low serum/urinary cortisol)

Question 18

How is addison’s disease managed? What are the risks?

Answer 18

Endo - steroids. Adrenal crisis needs IV fluid + 100mg hydrocort or 40mg pred. Have emergency bracelet, increase steroids when sick, steroid script for travel.

Question 19

What are the causes of cushings syndrome? What tests are indicated?

Answer 19

Steroids, pituitary ACTH excess, adrenal hyperplasia or tumour, ectopic ACTH production (eg. lung). 1mg dex suppression test or midnight salivary cortisol w sponge, no food/stress 60minprior (twice) or 24hr urine cortisol (twice).

Question 20

Conn’s syndrome - features, test

Answer 20

Hypertension, weakness, polyuria, low potassium. High aldosterone to renin ratio. Conn’s from adenoma, otherwise bilateral hyperplasia can mimic.

Question 21

What is the workup for an adrenal mass?

Answer 21

Dedicated CT best. Test for activity: dex suppression test (cushings), 24hr urine metanephrines + catecholamines (phaeo), aldosterone renin ratio if hypertensive. If >4cm or symptomatic/diseased, consider surgery.

Question 22

What medications are required after weight loss surgery? How is diabetes tested for?

Answer 22

Multivitamin, ca, vitamin D. Avoid NSAIDs. Can’t do OGTT due to risk of dumping syndrome.

Question 23

Symptoms and causes of prolactinaemia

Answer 23

Menstrual irregularity, infertility, galactorrhoea, erectile dysfunction, reduced libido. Causes: prolactinoma, pregnancy, hypothyroidism, surgery, drugs - cannabis, OCP, antipsychotis, metoclopramide.

Question 24

What is the management of prolactinaemia?

Answer 24

If tumour >10mm can cause headache/vision change. Dopamine agonist: Cabergoline helps for function and size, 2nd line bromocriptine. OCP for galactorrhoea. Surgery/radiotherapy if large or not responding.

Question 25

Symptoms and causes of male androgen deficiency

Answer 25

Sx: low libido, less face hair, gynaecomastia, fatigue, reduced muscle bulk, small testes. Primary (high FSH/LH): klinefelter (XXY), cryptoorchidism, trauma, radiaiton/toxin to testes. Secondary/central: pituitary tumour, pituitary surgery/radiotherapy, haemochromatosis, GnRH analgoues, exogenous androgens, systemic illness.

Question 26

What are 2 disorders of ADH? Causes and treatment

Answer 26

Diabetes insipidus - post operative (common),tumour, infection. Desmopressin. SIADH - cancer, intracranial lesion, antipsychotics. Fluid restrict, treat cause.

Question 27

Carcinoid and acromegaly - features, test.

Answer 27

Flushing, diarrhoea, valve disease, telangiectasia. 24h urine 5-HIAA. A: frontal bossing, HTN, diabetes,OSA. IGF-1 for screening.

Question 28

Hyperparathyroidism - features, cause and management.

Answer 28

Commonest cause of high calcium, usually from a single adenoma. Need surgery. Monitor if >50, Asx, no stones or renal impairment, Ca < 2.90, no osteoporosis. Avoid VitD/Ca supplement, water.