Clinical Abnormalities of Glands Flashcards
What is hyper-
Hormone over secretion
What is hypo-
Hormone under secretion
What is primary in relation to hyper-
Too much hormone coming from gland itself
What is secondary in relation to hyper-
One gland secretes too much of the hormone that controls the other gland, make it overactive
What is primary in relation to hypo-
Too little hormone coming from gland itself
What is secondary in relation to hypo-
One gland secretes too little of the hormone that controls the other gland, making it underactive
How can tumours affect glands?
Can destroy the gland and cause underactive gland (often occurs in pituitary, compresses tissue as cannot expand)
What is over-secretion usually caused by?
Usually benign tumours
What is under-secretion usually caused by?
Gland destruction due to:
- Inflammation (including autoimmune)
- Infarction (blood supply stops and tissue dies)
How can tumours/nodules contribute to endocrine gland diseases?
Have hormone production
What is prolactin over-secretion caused by?
- Usually due to a pituitary tumour secreting prolactin (prolactinoma)
- Can be due to a tumour sitting between pituitary gland and hypothalamus, suppressing the interaction between the two. Prolactin levels increase as no inhibitory effect
What is the clinical presentation of prolactin over-secretion?
- Galactorrhoea (breast milk production)
- Amenorrhoea (periods stop in women, sexual dysfunction in men)
- Headaches and visual field problems in large tumours
How can you diagnose prolactin over-secretion?
Use a static test
What can mildly raised prolactin be due to?
- Sex (nipple stimulation)
- Stress
- Drugs (antipsychotics and antidepressants)
- Non-functioning pituitary tumours
How do non-functioning pituitary tumours cause mildly raised prolactin?
Compress the hypothalamus and interfere with the inhibitory effect on prolactin secretion
How can prolactinomas be treated?
Are the only over-secreting pituitary tumour that can be treated medically (rarely require surgical intervention)
What is consequence of GH over-secretion in children?
- Excessive growth spurt
- Increased size of hands and feet
- If left untreated, can lead to gigantism
What is consequence of GH over-secretion in adults?
- Affects skin, soft tissue and skeleton (acromegaly)
- Increased sweating
- Wide and large hands/feet
How can you diagnose GH over-secretion?
Suppression test is necessary:
- Glucose is given
- GH measurements taken at different times
- In healthy people, glucose suppresses GH production
How can presence of pituitary tumour be confirmed?
MRI (imaging)
How can tumour causing GH over-secretion be treated?
Surgical removal of tumour. Radiotherapy and medical therapy may also be needed as surgery doesn’t always remove whole tumour
What are the clinical presentations of Cushing’s syndrome?
- Growth arrest in children
- Round, moon-like face
- Acne
- Hirsutism (growth of hair on woman’s face and body)
- Fat redistribution - truncal obesity and thin extremities
- Thin skin and easy bruising
- Striae on abdomen
What are the complications of Cushing’s syndrome?
- Hypertension
- Diabetes mellitus
- High risk of infections
- Poor wound healing
What is treatment for pituitary and adrenal related Cushing’s?
Surgery (radiotherapy and medical treatment may also be required)
What is treatment for cancer related Cushing’s?
Treat original cancer
What is Cushing’s syndrome?
Condition caused by excess production of cortisol in the body, regardless of the cause
What is Cushing’s disease?
When Cushing’s syndrome is caused by pituitary tumour secreting excess amounts of ACTH
What’s the most common cause of Cushing’s syndrome?
Pituitary tumour secreting ACTH (Cushing’s disease)
What are the other causes of Cushing’s syndrome?
- Non pituitary tumours that produce ACTH (ectopic) e.g. lungs
- Benign or malignant tumours of the adrenal gland which produce excess cortisol leading to low ACTH levels (negative feedback)
What test can be used to diagnose Cushing’s?
Suppression test using dexamethasone
What is dexamethasone?
Man-made steroid similar to cortisol that is used to confirm the failure of cortisol production
What is the effect of dexamethasone in normal people?
Reduces ACTH release (negative feedback), therefore reducing cortisol
What are the 2 types of dexamethasone tests?
Low-dose and high-dose
What are results of dexamethasone test in Cushing’s syndrome caused by pituitary tumours (Cushing’s disease) or cancers?
Low dose test
- No decrease in blood cortisol
- Detectable/high ACTH
High dose test
- Decrease in blood cortisol as production of ACTH by pituitary adenomas usually suppressed
What are results of dexamethasone test in Cushing’s syndrome caused by adrenal tumour?
Low dose test
- No decrease in blood cortisol
- Low/undetectable ACTH
