Endocrinology - Principles, GH and Acromegaly

Question 1

What are hormones? List their types?

What are endocrine hormones?

How do hormones act?

What do hormones do?

Answer 1

Hormones - chemical messengers of the body

• peptides
• proteins
• steroids (based on 4 rings derived from cholesterol)

Endocrine hormones: released by specialist secretory cells and act at a distant site

Hormones either act via cell membrane receptors or intracellular receptors

Hormones maintain homeostasis (salt and water, blood glucose), essential for reproductive functions

Question 2

List the endocrine organs of the body:

Answer 2

• Brain: hypothalamus, pituitary gland
• Thyroid gland: parathyroid glands
• Adrenal glands above kidneys
• Pancreas
• Ovaries/testes

Question 3

What can go wrong in the endocrine system?

How are endocrine disorders investigated?

Answer 3

Overproduction of hormone: benign or malignant tumours

Underproduction: auto-immune disease, enzymatic defects, drug side effects

Investigations:

• blood analysis of pituitary hormones and organ hormones
• imaging of brain and endocrine organs
• may be complex and dynamic
• endocrinologists will direct investigations and management

Question 4

How are endocrine disorders managed?

Answer 4

• replace and monitor for hormone insufficiency
• suppression and monitor for hormone excess
• surgery

Question 5

What is diabetes insipidus?

How is it managed?

Answer 5

Lack of ADH or renal insensitivity to ADH due to

• hypothalamic disease
• nephrogenic DI

Causes polyuria, polydipsia and dehydration if inadequate fluid intake. Can be 10-15L urine per day.

Management:

• synthetic ADH (desmopressin, DDAVP)
• intranasal, sublingual, injectable, oral formulations available

In dental treatment, no dose adjustment or special monitoring needed. Just take the usual dose.

Question 6

What are the actions of growth hormone?

Answer 6

GH stimulates body growth by causing the liver to release insulin-like Growth Factor 1

IGF-1 increases collagen and protein synthesis and other growth promoting actions

GH release is intermittent, mainly released at night, especially during REM sleep

Question 7

What disease states occur from growth hormone issues?

What is the most common cause of GH disease?

Answer 7

• GH excess in children causes gigantism
• GH excess in adults causes acromegaly (epiphyses of bone have fused, so different presentation)
• GH stimulates skeletal and soft tissue growth and disease states reflect this

Majority of cases due to pituitary adenoma secreting GH

Question 8

What is acromegaly?

How is acromegaly diagnosed?

Answer 8

• excess GH causes widening and coarsening of bones and growth of soft tissues
• characteristic appearance
• joint problems, arthritis, hypertension and glucose intolerance or diabetes are common in this condition
• Diagnosis made on measurement of plasma GH and IGF-1, often with brain imaging to look for pituitary adenoma

Question 9

List some signs and symptoms of acromegaly:

Dental aspects:

Management:

Answer 9

• increased size of hands, feet
• headache, visual deterioration
• weight gain, tiredness
• goitre, pain/tingling/joint pain
• prognathism - jaw grows wider
• interdental separation, enlarged tongue (macroglossia)

Dental aspects:

• may present with oro-facial signs –> SBAR handover to GP

Management:

• neuro-surgery to remove adenoma