Week 23 - Hyperparathyroidism, hypothyroid, thyroid eye disease and thyrotoxicosis

Question 1

in what cases is hyperparathyroidism most clinically significant

Answer 1

in cases of chronic kidney disease

Question 2

what are the PTH and calcium levels in primary hyperparathyroidism

Answer 2

PTH - normal
Calcium - high

Question 3

what are the causes of primary hyperparathyroidism

Answer 3

tumour of the parathyroid gland (rare)

Question 4

what are the PTH and calcium levels in secondary hyperparathyroidism

Answer 4

PTH - high
calcium - low

Question 5

what are the causes of secondary hyperparathyroidism

Answer 5

a low level of calcium induces the parathyroid gland to produce large amounts of PTH

low levels of calcium are also commonly due to chronic renal failure

can also be caused by insuddicient vitamin D, insufficient calcium in the diet, excessive magnesium in the diet

Question 6

what are the PTH and calcium levels in tertiary hyperparathyroidism

Answer 6

PTH - high
calcium - high

Question 7

what are the causes of teritiary hyperparathyroidism

Answer 7

basically occurs after years of secondary hyperparathyroidism, after the secondary cause has been resolved

the parathyroid gland has been used to producing such high levels of PTH for so long, it basically just broken and secretes high levels of PTH even though levels of calcium are now responsive to PTH.

there is hyperplasia of the glands, and loss of response to calcium

Question 8

what does hypothyroid refer to

Answer 8

insufficient thyroid hormones - T3, T4

Question 9

what is primary hypothyroidism

Answer 9

where the thyroid behaves abnormally and produces inadequate thyroid hormones. negative feedback is absent, resulting in increased production of TSH

Question 10

what are the TSH and T3,T4 levels in primary hypothyroidism

Answer 10

TSH is raised, T3,T4 are low

Question 11

what is secondary hypothyroidism

Answer 11

where the pituitary gland behaves abnormally and produces inadequate TSH

this results in under-stimulation of the thyroid and insufficient T3,T4 levels

Question 12

what are the levels of TSH, T3,T4 in secondary hypothyroidism

Answer 12

are ALL low

Question 13

what is the most common cause of hypothyroidism

Answer 13

Hashimoto’s thyroiditis

Question 14

what is hashimotos

Answer 14

an autoimmune condition causing inflammation of the thyroid gland.

Question 15

what antibodies is Hashimoto’s associated with

Answer 15

anti-thyroid peroxidase (anti-TPO) antibodies and anti-thyroglobulin (anti-Tg) antibodies.

Question 16

what is the most common cause of hypothyroidism in the developing world

Answer 16

iodine deficiency

Question 17

what treatments for hyperthyroidism can cause hypothyroidism

Answer 17

Carbimazole
Propylthiouracil
Radioactive iodine
Thyroid surgery

Question 18

what does amiodarone interfere with

Answer 18

thyroid hormone production and metabolism, usually causing hypothyroidism but can also cause thyrotoxicosis.

Question 19

what causes a goitre in hypothyroidism

Answer 19

iodine deficiency

Question 20

what is the mainstay of treatment of hypothyroidism

Answer 20

levothyroixine

synthetic version of T4 and metabolises to T3 in the body

Question 21

how is the dosage of levothyroxine managed

Answer 21

the dose is titrated based on the TSH level, initially every 4 weeks

Question 22

what is the synthetic version of T3 that is very rarely used when leveothyroixine is not tolerated

Answer 22

Liothyronine sodium

Question 23

what is thyroid eye disease typically associated with the signs of

Answer 23

Grave’s disease - goitre, acropathy, hyperthyroidism and pretibial myxodema

Question 24

what are the clinical features of thyroid eye disease

Answer 24

Swelling of the eyelids
Oedema (chemosis) and engorgement of vessels of conjunctiva
Exposure of the cornea (loss of blink, apparent lid retraction)
Pronounced exophthalmos (if absent because tight orbital septum may restrain contents and lead to raised intraorbital pressure and optic nerve compression)
Restricted eye movements (infiltration of muscles by inflammatory cells, inflammation, oedema and fibrosis)
Optic neuropathy (fundal vascular congestion, swelling or atrophy of disc)

Question 25

what is the management of thyroid eye disease

Answer 25

Includes excluding or treating thyroid dysfunction, smoking cessation and artificial tears/ointments
o Lid retraction can be reduced by guanethidine drops (relax smooth muscle)
o If corneal exposure threatens sight, tarsoraphy performed.
o In serious disease with corneal problems or pressure on CN II: high dose steroids, surgical orbital decompression and radiotherapy.

Question 26

what kind of tremor is seen in thyrotoxicosis

Answer 26

fine tremor

Question 27

what is a thyrotoxic storm

Answer 27

severe acute presentation of thyrotoxicosis

Question 28

what are the features of thyrotoxic storm

Answer 28

A marked fever (>38.5’)
Seizures
Vomiting
Diarrhoea
Jaundice
Death – can be caused by arrhythmias, heart failure or hyperthermia.

Question 29

what is the treatment of thyrotoxic storm

Answer 29

Treatment should be started as soon as possible – and patients should be given propanolol, antithyroid drugs, potassium iodide (to reduce vascular flow to the gland) and corticosteroids.