Endocrinology 4

Question 1

Primary hyperthyroidism is very common; whereas secondary hyperthyroidism is very rare.

In which population is hyperthyroidism most common?

Answer 1

In females - as it is usually due to autoimmune conditions. Women are more likely to have autoimmune conditions.

Question 2

What are the causes of hyperthyroidism?

Answer 2

• Graves’ disease (80%) - Autoimmune condition. The individual produces antibodies that work similar to TSH
• Toxic nodule/ Toxic multi-nodular goitre (MNG) (15%) A nodule works independent of the pituitary
• Thyroiditis (1%) Usually due to a viral infection. The thyroid will become inflamed and damaged, this leads to the release of thyroid hormones and so hyperthyroidism. It however means that since the thyroid gland is damaged, it then leads to hypothyroidism. Thyroid gland is tender to touch.
• Other such as Drugs such as Amiodarone used in the treatment of arrhythmias. This is as 40% of the drug is iodine.

Question 3

What is the clinical presentation of Graves’ disease?

Answer 3

• Heat intolerant (sweating)
• Irritability, insomnia and hyperactivity
• Palpitations and fast pulse
• Hypertension
• weight loss despite over eating
• Menstrual problems

Question 4

What are the extrathyrodial signs of Graves’ disease?

Answer 4

• Bulging eyes (proptosis)
• Periorbital oedema - swelling under the eyes
  This may be due to a common antigen between the tissue behind the eyes and that in the thyroid.
• `Paralysis of the eye (Ophthalmoplegia) This can leads to double vision.

Question 5

How do you examine for hyperthyroidism?

Answer 5

• Hand tremor (paper on hand)
• Heart rate
• Increasing sweating
• Lid lag

Inspect the thyroid:

• Smooth -> Graves’ disease
• Nodular -> Toxic nodule(s)
• tender - Thyroiditis

Also palpate the thyroid, auscultate `(listen as in Graves’ you can hear bruit over the thyroid - due to high blood flow); precise (want to see if the thyroid extends into the thorax).

Question 6

What are the treatments for Graves’ disease?

Answer 6

• Antithyroid drugs such as carbimazole. Treat for 6-18 months. Can induce remission in half the patients. These drugs can suppress the white cell production in the body.
• Radioactive iodine - this will destroy the thyroid gland leading to hypothyroidism. This can easily be treated.
• Surgery

Question 7

What are the symptoms of growth hormone deficiency?

Answer 7

Children - Stunted growth

Adults - asymptomatic, tiredness and depression (non-specific).

Question 8

How do you test for GH under-secretion? What are the treatments?

Answer 8

Glucagon stimulation test or insulin stress test.
Treatment is Growth hormone replacement. Use injections. In children, use the injections; if asymptomatic in adult you may not treat them. You need to assess whether they are eligible for treatment.

Question 9

What is the clinical presentation of steroid under-secretion? What is the test? What is the treatment?

Answer 9

Children: Stunted growth
Adults: Severe tiredness, dizziness due to low blood pressure, abdominal pain, vomiting and diarrhoea

Synacthen test if primary adrenal failure is suspected. If you want to differentiate between primary and secondary you need a glucagon stress test or an insulin stress test.

Treatment: replace the missing hormones.

Question 10

What are the causes of hypothyroidism?

Answer 10

Very common particularly in older ladies.

Primary:

• Usually autoimmune
• Can be drug induced e.g. by amiodarone.

Secondary (rare):
- Usually a part of complete pituitary failure

Question 11

What are the clinical presentations of hypothyroidism?

Answer 11

• Weight gain
• Constipation
• Cold and decreased sweating
• Weakness and dry skin
• Hair loss
• Impaired memory

Question 12

What is Addison’s disease?

Answer 12

Addison’s disease, also known as primary adrenal insufficiency and hypocortisolism, is a long-term endocrine disorder in which the adrenal glands do not produce enough steroid hormones. Symptoms generally come on slowly and may include abdominal pain, weakness, and weight loss.

Question 13

What is the presentation of sex hormone deficiency?

Answer 13

Males: Reduced libido and erectile dysfunction
Females: Amenorrhoea

Question 14

What are the causes of amenorrhoea?

Answer 14

• Ovarian problems
• Uterine Problems
• Pituitary Problems
• Hypothalamic Problems

Question 15

What are causes of pituitary failure?

Answer 15

• Infarction e.g. after extended labour, the blood pressure drops and the pituitary failure causing Sheehan’s syndrome (postpartum pituitary gland necrosis, is hypopituitarism)
• Cancers
• Others

Question 16

What are the causes of Hyperparathyroidism?

Answer 16

• Cancers secrete ACTH
• Drugs
• Hyperparathyroidism

Question 17

What is the clinical presentation of hypercalcaemia?

Answer 17

• Thirsty
• Pass too much urine
• Constipation as high calcium levels cause constipation (also hypothyroidism)
• Abdominal pain

Question 18

Make a diagnosis:
Patient 1:
Calcium 3.1 mmol/L (normal 2.2 - 2.6)
PTH 14.2 pmol/L (normal 1.0 - 6.0)

Patient 2:
Calcium 3.2 mmol/L
PTH < 0.1 (undetectable)

Answer 18

Patient 1:
Hypercalcaemia
Primary Hyperparathyroidism. This is as PTH is high, causing Calcium levels to increase.

Patient 2:
Hyperthyroidism.
There is something else that is causing high calcium. It is secondary hyperparathyroidism. Secondary hyperparathyroidism is a condition in which a disease outside of the parathyroid glands causes all of the parathyroid glands to become enlarged and hyperactive.

Question 19

What is PTH?

Answer 19

Parathyroid hormone. It is a hormone secreted by the parathyroid glands that regulates the serum calcium through its effects on bone, kidney, and intestine.