Thyroid and Parathyroid

Question 1

What are causes of primary hyperparathyroidism?

Answer 1

• 80%: solitary adenoma
• 15%: hyperplasia
• 4%: multiple adenoma
• 1%: carcinoma

Question 2

What are clinical features of Primary Hyperparathyroidism?

Answer 2

• Typically seen in elderly females
  
  • ‘bones, stones, abdominal groans and psychic moans’
    
    • Polydipsia
    • Polyuria
    • Peptic ulceration/Constipation/Pancreatitis
    • Bone pain/fracture o
    • Renal stones
    • Depression
    • Hypertension
    • MEN1 and MEN 2

Question 3

What are some investigations for Primary Hyperparathyroidisim?

Answer 3

• Elevated calcium,
• Low phosphate
• Elevated PTH (or normal)
• Urine calcium : creatinine clearance ratio > 0.01
• Technetium-MIBI subtraction scan
• Pepperpot skull is a characteristic X-ray finding of hyperparathyroidism

Question 4

What is the management of Primary hyperparathyroidism?

Answer 4

• Definitive: Total parathyroidectomy
• Cinacalcet used sometimes in patients who are unsuitable for surgery

Question 5

What are causes of secondary hyperparathyrodism?

Answer 5

Parathyroid gland hyperplasia occurs as a result of low calcium, almost always in a setting of chronic renal failure

Question 6

What are some clinical features of those with Secondary Hyperparthyrodism?

Answer 6

• May have few symptoms
• Eventually may develop bone disease, osteitis fibrosa cystica and soft tissue calcifications

Question 7

What are signs on investigations for those with Secondary Hyperparathyroidism?

Answer 7

• PTH (Elevated)
• Ca2+ (Low or normal)
• Phosphate (Elevated)
• Vitamin D levels (Low)

Question 8

What are causes of Tertiary Hyperparathyroidism?

Answer 8

Occurs as a result of ongoing hyperplasia of the parathyroid glands after correction of underlying renal disorder, hyperplasia of all 4 glands is usually the cause

Question 9

What are investigations for Tertiary Hyperparathyroidism?

Answer 9

• Ca2+(Normal or high)
• PTH (Elevated)
• Phosphate levels (Decreased or Normal)
• Vitamin D (Normal or decreased)
• Alkaline phosphatase (Elevated)

Question 10

What are clinical features of Tertiary Hyperparathyroidism?

Answer 10

• Metastatic calcification
• Bone pain and / or fracture
• Nephrolithiasis
• Pancreatitis

Question 11

What are the main symptoms of hypoparathyroidism?

Answer 11

• Tetany: muscle twitching, cramping and spasm
• Perioral paraesthesia
• If chronic: depression, cataracts

Question 12

What are signs of Hypoparathyroidism?

Answer 12

• Trousseau’s sign: carpal spasm if the brachial artery occluded by inflating the blood pressure cuff and maintaining pressure above systolic
• Chvostek’s sign: tapping over parotid causes facial muscles to twitch
• ECG: prolonged QT interval

Question 13

What are is the causes of Primary hypoparathyroidism and how is it investigated and treated?

Answer 13

• Decreased PTH secretion • e.g. secondary to thyroid surgery*
• Low Calcium, High Phosphate
• Treated with Alfacalcidol

Question 14

What causes Hyperthyroism?

Answer 14

• Graves’ Disease
• Thyroiditis
• Toxic Multinodular Goitre
• Solitary toxic thyroid adenoma

Question 15

What are symptoms of Hyperthyroidsm?

Answer 15

• Weight loss, despite an increased appetite, although a few patients may gain weight
• Palpitations/rapid pulse
• Sweating and heat intolerance
• Tiredness and weak muscles
• Nervousness and irritability
• Shakiness
• Mood swings or aggressive behaviour
• Looseness of the bowels and occasionally nausea
• Warm, moist hands
• Thirst
• Passing larger than usual amounts of urine
• Enlarged thyroid gland
• Thyroid eye disease

Question 16

What is Graves’ disease?

Answer 16

Graves’ disease is the most common cause of thyrotoxicosis. It is typically seen in women aged 30-50 years

Question 17

What are specific clinical signs of Graves’ disease?

Answer 17

• Eye signs (30% of patients):
  
  • exophthalmos, ophthalmoplegia
• Pretibial myxoedema
• Thyroid acropachy

Question 18

What are the Autoantibodies involved in Graves’ disease?

Answer 18

• TSH receptor stimulating antibodies (90%)
• Anti-thyroid peroxidase antibodies (75%)

Question 19

What is Subacute Thyroiditis?

Answer 19

Subacute thyroiditis (also known as De Quervain’s thyroiditis and subacute granulomatous thyroiditis) is thought to occur following viral infection and typically presents with hyperthyroidism.

Question 20

What are the phases of Subacute Thyroiditis?

Answer 20

• Phase 1 (lasts 3-6 weeks): hyperthyroidism, painful goitre, raised ESR
• Phase 2 (1-3 weeks): euthyroid
• Phase 3 (weeks - months): hypothyroidism
• Phase 4: thyroid structure and function goes back

Question 21

What are the definitive investigations for Subacute Thyroiditis?

Answer 21

Thyroid scintigraphy: globally reduced uptake of iodine-131

Question 22

How is Subacute Thyroiditis managed?

Answer 22

• Usually self-limiting - most patients do not require treatment
• Thyroid pain may respond to aspirin or other NSAIDs
• In more severe cases steroids are used, particularly if hypothyroidism develops

Question 23

What is a Toxic Multinodular Goitre?

Answer 23

Toxic multinodular goitre describes a thyroid gland that contains a number of autonomously functioning thyroid nodules resulting in hyperthyroidism.

Question 24

What is the investigation and treatment for a Multinodular Goitre?

Answer 24

• Nuclear scintigraphy reveals patchy uptake.
• The treatment of choice is radioiodine therapy.

Question 25

What is a Thyroid Storm?

Answer 25

* Thyroid storm is a rare but life-threatening complication of thyrotoxicosis. * It is typically seen in patients with established thyrotoxicosis and is rarely seen as the presenting feature. * Iatrogenic thyroxine excess does not usually result in thyroid storm

Question 26

What are clinical features of a Thyroid Storm?

Answer 26

* Fever \> 38.5ºC * Tachycardia * Confusion and agitation * Nausea and Vomiting * Hypertension * Heart failure * Abnormal liver function test

Question 27

What is the management of a Thyroid Storm?

Answer 27

* Symptomatic treatment e.g. paracetamol * Treatment of underlying precipitating event * Propranolol * Anti-thyroid drugs: e.g. methimazole or propylthiouracil • Lugol's iodine * Dexamethasone (e.g. 4mg IV qds) - blocks the conversion of T4 to T3

Question 28

What are symptoms of Hypothyrodism?

Answer 28

* General * Weight gain * Lethargy * Cold intolerance * A hoarse voice is also occasionally noted * Skin * Dry (anhydrosis), Cold, Yellowish skin * Non-pitting oedema (e.g. hands, face) * Dry, coarse scalp hair, loss of lateral aspect of eyebrows * Gastrointestinal * Constipation * Gynaecological * Menorrhagia * Neurological * Decreased deep tendon reflexes * Carpal tunnel syndrome

Question 29

What is the investigation for Hypothyroidism?

Answer 29

TFTs

Question 30

How is Hypothyrodism managed?

Answer 30

* For patients with cardiac disease, severe hypothyroidism or patients over 50 years the initial starting dose should be 25mcg od of Levothyroxine with dose slowly titrated. * Other patients should be started on a dose of 50-100mcg od * The therapeutic goal is 'normalisation' of the thyroid stimulating hormone (TSH) level (TSH value 0.5-2.5 mU/l) * Following a change in thyroxine dose thyroid function tests should be checked after 8-12 weeks * Women with established hypothyroidism who become pregnant should have their dose increased 'by at least 25-50 micrograms levothyroxine'\* due to the increased demands of pregnancy. The TSH should be monitored carefully, aiming for a low-normal value

Question 31

What are side effects of Thyroxine Therapy?

Answer 31

* Hyperthyroidism: due to over treatment * Reduced bone mineral density * Worsening of angina * Atrial fibrillation

Question 32

What are some interactions of thyroxine therapy?

Answer 32

Iron: absorption of levothyroxine reduced, give at least 2 hours apart

Question 33

How is a Myxoedemic Coma managed?

Answer 33

* Levothyroxine is used to replace the low levels of thyroid hormone causing the patient's symptoms. * Hydrocortisone is given to treat adrenal insufficiency. * Patients suffering from a myxoedemic coma due to secondary hypothyroidism are at risk of hypopituitarism due to the location of the lesion. Thus patients are treated as presumed adrenal insufficiency until it has been ruled out.

Question 34

What is Subclinical hypothyroidism?

Answer 34

TSH raised but T3, T4 normal with no obvious symptoms

Question 35

What is the significance of Subclinical Hypothyroidism?

Answer 35

* Risk of progressing to overt hypothyroidism is 2-5% per year (higher in men) * Risk increased by the presence of thyroid autoantibodies

Question 36

What is the management of Subclinical Hypothyroidism?

Answer 36

* TSH is between 4 - 10mU/L and the free thyroxine level is within the normal range * if \< 65 years with symptoms suggestive of hypothyroidism, give a trial of levothyroxine. If there is no improvement in symptoms, stop levothyroxine * 'in older people (especially those aged over 80 years) follow a 'watch and wait' strategy, generally avoiding hormonal treatment' * if asymptomatic people, observe and repeat thyroid function in 6 months * TSH is \> 10mU/L and the free thyroxine level is within the normal range * Start treatment (even if asymptomatic) with levothyroxine if \<= 70 years * 'in older people (especially those aged over 80 years) follow a 'watch and wait' strategy, generally avoiding hormonal treatment'