MRSC

Question 1

parathyroid glands function

Answer 1

control the level of calcium and phosphates in the blood.

Question 2

role of calcium

Answer 2

Calcium is involved with:
Contraction of skeletal, cardiac and smooth muscle
Blood clotting
Control of nerve impulses
Increases in the level of calcium cause depression of the nervous system
Decreases in the level of calcium causes excitation of the nervous system

Question 3

PTH – hormone

Answer 3

PTH will cause a rise in serum concentrations of calcium and a fall in serum concentrations of phosphate

increasing calcium and phosphate absorption from the gut.

Question 4

Calcitonin

Answer 4

hormone released by the thyroid gland in response to high levels of calcium in the blood

Decreased absorption of bone by osteoclasts
Decreased formation of new osteoclasts –

Question 5

Primary Hyperparathyroidism

Answer 5

Normal PTH
High calcium
causes = tumour of parathyroid

Question 6

2ndary

Answer 6

high PTH
low calcium

Low levels of Ca2+ are commonly due to chronic renal failure. Can also be caused by insufficient vit D, insufficient Ca2+ in the diet, excessive Mg2+ in the diet

Question 7

Medullary thyroid carcinoma

Answer 7

This is associated with parathyroidism (often tertiary) as a result of hyperadrenalism. Together, these are all classed as multiple endocrine neoplasia syndrome (MEN) type I

Question 8

Multiple endocrine neoplasia (MEN) type 2

Answer 8

a genetic condition characterised by neoplasia of the thyroid (medullary cell carcinoma), parathyroid (parathyroid adenoma) and adrenal glands (phaeochromocytoma

Question 9

primary hypothyroidism

Answer 9

autoimmune disorder affecting thyroid tissue

Hashimoto’s thyroiditis
most common cause in the developed world
autoimmune disease, associated with type 1 diabetes mellitus, Addison’s or pernicious anaemia
may cause transient thyrotoxicosis in the acute phase
5-10 times more common in women

High TSH, Low T3/4

Question 10

secondary hypothyroidism

Answer 10

disorder with the pituitary gland (e.g.pituitary apoplexy) or a lesion compressing the pituitary gland

low TSH low t3/4

Question 11

Subacute thyroiditis (de Quervain’s)

Answer 11

associated with a painful goitre and raised ESR

Question 12

Sick euthyroid syndrome

Answer 12

low TSH low t3/4

Question 13

Poor compliance with thyroxine

Answer 13

high TSG and Low T3/4

Patients who are poorly compliant may only take their thyroxine in the days before a routine blood test. The thyroxine levels are hence normal but the TSH ‘lags’ and reflects longer term low thyroxine levels

Question 14

Graves’ disease

Answer 14

TSH down, T4 and T3 up
thyroid autoantibodies
other investigations are not routinely done but includes isotope scanning

Question 15

thyroid malignancies - papillary cancer

Answer 15

Papillary -> most common - Often young females - excellent prognosis

Usually contain a mixture of papillary and colloidal filled follicles
Histologically tumour has papillary projections and pale empty nuclei
Seldom encapsulated
Lymph node metastasis predominate
Haematogenous metastasis rare

Question 16

Follicular thyroid cancer (adenoma)

Answer 16

Usually present as a solitary thyroid nodule

Malignancy can only be excluded on formal histological assessment

Question 17

Management of papillary and follicular cancer

Answer 17

total thyroidectomy
followed by radioiodine (I-131) to kill residual cells
yearly thyroglobulin levels to detect early recurrent disease

Question 18

thyroid Follicular carcinoma

Answer 18

May appear macroscopically encapsulated, microscopically capsular invasion is seen. Without this finding the lesion is a follicular adenoma.
Vascular invasion predominates
Multifocal disease raree

Question 19

Medullary carcinoma

Answer 19

C cells derived from neural crest and not thyroid tissue
Serum calcitonin levels often raised
Familial genetic disease accounts for up to 20% cases
Both lymphatic and haematogenous metastasis are recognised, nodal disease is associated with a very poor prognosis.

Question 20

thyroglossal cysts

Answer 20

More common in patients < 20 years old.

Features
usually midline, between the isthmus of the thyroid and the hyoid bone
moves upwards with protrusion of the tongue
may be painful if infected

Question 21

Thyroid surgery: complications

Answer 21

Complications following surgery
Anatomical such as recurrent laryngeal nerve damage.
Bleeding. Owing to the confined space haematoma’s may rapidly lead to respiratory compromise owing to laryngeal oedema.
Damage to the parathyroid glands resulting in hypocalcaemia.

Question 22

prevention of thyroid eye disease

Answer 22

smoking is the most important modifiable risk factor for the development of thyroid eye disease

radioiodine treatment may increase the inflammatory symptoms seen in thyroid eye disease.

In a recent study of patients with Graves’ disease around 15% developed, or had worsening of, eye disease. Prednisolone may help reduce the risk

Question 23

thyroid eye disease

Answer 23

exophthalmos
conjunctival oedema
optic disc swelling
ophthalmoplegia
inability to close the eyelids may lead to sore, dry eyes. If severe and untreated patients can be at risk of exposure keratopathy

Management
topical lubricants may be needed to help prevent corneal inflammation caused by exposure
steroids
radiotherapy
surgery

Question 24

Primary hyperparathyroidism

Indications for surgery

Answer 24

Elevated serum Calcium > 1mg/dL above normal
Hypercalciuria > 400mg/day
Creatinine clearance < 30% compared with normal
Episode of life threatening hypercalcaemia
Nephrolithiasis
Age < 50 years
Neuromuscular symptoms
Reduction in bone mineral density of the femoral neck, lumbar spine, or distal radius of more than 2.5 standard deviations below peak bone mass (T score lower than -2.5)

Question 25

Secondary hyperparathyroidism treatment

Answer 25

Usually managed with medical therapy. Indications for surgery in secondary (renal) hyperparathyroidism: Bone pain Persistent pruritus Soft tissue calcifications

Question 26

Side-effects of thyroxine therapy

Answer 26

hyperthyroidism: due to over treatment reduced bone mineral density worsening of angina atrial fibrillation

Question 27

Pseudohypoparathyroidism

Answer 27

target cells being insensitive to PTH due to abnormality in a G protein associated with low IQ, short stature, shortened 4th and 5th metacarpals low calcium, high phosphate, high PTH diagnosis is made by measuring urinary cAMP and phosphate levels following an infusion of PTH. In hypoparathyroidism this will cause an increase in both cAMP and phosphate levels. In pseudohypoparathyroidism type I neither cAMP nor phosphate levels are increased whilst in pseudohypoparathyroidism type II only cAMP rises.

Question 28

Riedel's thyroiditis

Answer 28

characterised by dense fibrous tissue replacing the normal thyroid parenchyma. On examination a hard, fixed, painless goitre is noted. It is usually seen in middle-aged women. It is associated with retroperitoneal fibrosis.

Question 29

Congenital adrenal hyperplasia causes

Answer 29

Cause 21-hydroxylase deficiency (90%) 11-beta hydroxylase deficiency (5%) 17-hydroxylase deficiency (very rare)

Question 30

21-hydroxylase deficiency features

Answer 30

virilisation of female genitalia precocious puberty in males 60-70% of patients have a salt-losing crisis at 1-3 wks of age

Question 31

11-beta hydroxylase deficiency features

Answer 31

virilisation of female genitalia precocious puberty in males hypertension hypokalaemia

Question 32

17-hydroxylase deficiency features

Answer 32

non-virilising in females inter-sex in boys hypertension

Question 33

Addison's disease

Answer 33

Autoimmune destruction of the adrenal glands is the commonest cause of primary hypoadrenalism in the UK, eatures lethargy, weakness, anorexia, nausea & vomiting, weight loss, 'salt-craving' hyperpigmentation (especially palmar creases)*, vitiligo, loss of pubic hair in women, hypotension, hypoglycaemia hyponatraemia and hyperkalaemia may be seen crisis: collapse, shock, pyrexia

Question 34

Cushings causes

Answer 34

ACTH dependent causes Cushing's disease (80%): pituitary tumour secreting ACTH producing adrenal hyperplasia ectopic ACTH production (5-10%): e.g. small cell lung cancer is the most common causes ACTH independent causes iatrogenic: steroids adrenal adenoma (5-10%) adrenal carcinoma (rare) Carney complex: syndrome including cardiac myxoma micronodular adrenal dysplasia (very rare) Pseudo-Cushing's mimics Cushing's often due to alcohol excess or severe depression causes false positive dexamethasone suppression test or 24 hr urinary free cortisol insulin stress test may be used to differentiate

Question 35

Primary hyperaldosteronism

Answer 35

bilateral idiopathic adrenal hyperplasia is the cause in up to 70% of cases adrenal adenoma, termed Conn's syndrome also a cause ``` Features hypertension hypokalaemia e.g. muscle weakness this is a classical feature in exams but studies suggest this is seen in only 10-40% of patients alkalosis ```

Question 36

Primary hyperaldosteronism investigations

Answer 36

vestigations the 2016 Endocrine Society recommend that a plasma aldosterone/renin ratio is the first-line investigation in suspected primary hyperaldosteronism should show high aldosterone levels alongside low renin levels (negative feedback due to sodium retention from aldosterone) following this a high-resolution CT abdomen and adrenal vein sampling is used to differentiate between unilateral and bilateral sources of aldosterone excess Adrenal Venous Sampling (AVS) can be done to identify the gland secreting excess hormone in primary hyperaldosteronism

Question 37

Conditions where HbA1c may not be used for diagnosis:

Answer 37

``` haemoglobinopathies haemolytic anaemia untreated iron deficiency anaemia suspected gestational diabetes children HIV chronic kidney disease people taking medication that may cause hyperglycaemia (for example corticosteroids) ```

Question 38

The following are key messages that should be given to all patients with diabetes if they become unwell:

Answer 38

Increase frequency of blood glucose monitoring to four hourly or more frequently Encourage fluid intake aiming for at least 3 litres in 24hrs If unable to take struggling to eat may need sugary drinks to maintain carbohydrate intake It is useful to educate patients so that they have a box of 'sick day supplies' that they can access if they become unwell Access to a mobile phone has been shown to reduce progression of ketosis to diabetic ketoacidosis