Pituitary Hypersecretion Syndromes Flashcards
Learn about the different syndromes
What is acromegaly caused by?
XS growth hormone production leads to gigantism in children and acromegaly in adults
How is growth hormone controlled?
- GH releasing hormone stimulates
- Somatostatin inhibits secretion
- Ghrelin, produced in the stomach increase GH
How does GH exert its influence?
- Via induction of insulin like growth factors (IGF-1)
2. Synthesized in tissues
What are the clinical features of acromegaly?
- Change in size of hands/feet
- Sweating, visual loss, fatigue, weight gain
- Amen/oligomenorrhea
- Galactorrhea, poor libido
- Polyuria, polydipsia
What are the investigations for Acromegaly
- Serum IGF-1 levels always raised
- Glucose tolerance test is diagnostic
- If IGF-1 raised then serum GH measured 2 hours after oral glucose load
- In a positive test there is failure of suppression of normal serum GH
What are the investigations for Acromegaly
- Serum IGF-1 levels always raised
- Glucose tolerance test is diagnostic
- If IGF-1 raised then serum GH measured 2 hours after oral glucose load
- In a positive test there is failure of suppression of normal serum GH
What is the management of Acromegaly?
- Aim is to reduce IGF-1 to age related levels
- Transphenoidal surgical resection
- Somatostatin analogues (Ocreotide/lanreotide)
- External radio therapy
What are the causes of hyper prolactaemia?
- Prolactinoma
- Primary hypothyroidism
- Drugs: metaclopramide, phenothiazines, oestrogens, cimetidine
- Polycystic ovaries
- Acromegaly
What are the clinical features of Hyperprolactaemia
- Galactorrhea
- Amenorrhea
- Loss of libido
- Erectile dysfunction
- If pituitary tumour bitemporal hemianopia
What are the investigations for hyperprolactaemia?
- Serum prolactin levels
- Thyroid function tests
- MRI
- Visual field testing
Management of Hyperprolactaemia?
- Causative drugs withdrawn
- Dopamine agonist: carbergoline 500mcg bi weekly
- Bromocriptine if preganacy planned
How is thyroid function assessed?
- Serum TSH concentration
- Serum free T4 or T3
- Drugs and illness can alter conc of T3/T4
- Oral contraceptive increases TBG hence T4
Define hypothyroidism?
- Under activity of thyroid gland
- Maybe primary from disease of thyroid
- Secondary to hypothalamus or pituitary
Characteristics of Thyrotoxicosis
TSH (down), T4 (up), T3, (up)
Characteristics in T function tests in Primary hypothyroidism?
TSH(up), T4(down/normal), T3(down/normal)
Characteristics of T function tests in TSH deficiency?
TSH(down/low/normal), T4/T3(down/normal)
What are the characteristics of T function tests for T3 toxicosis?
TSH(down), T4(normal), T3(up)
What is autoimmune thyroiditis?
- With a goitre (hashimoto’s)
- Thyroid atrophy
- Cell and antibody mediated destruction of thyroid tissue
- All patients have serum antibodies to Thyroglobulin
What drugs induce Hypothyroidism?
- Carbimazole
- Lithium
- Amiodarone
- Interferon
What are the clinical features of Hypothyroidism?
- Tiredness, weight gain, cold intolerance, goitre
2. Puffy eyes, brittle hair, dry skin, muscle weakness stiffness, constipation, meno/oligomenorrhea
What are the investigations for Hypothyroidism?
- High serum TSH confirms disease
- Thyroid antibodies maybe present
Other features include: - Anaemia
- Hyperlipaemia
- Hyponatraemia(due to inc ADH)
- Increased serum creatine kinase
What is the management of Hypothyroidism
- Life long Levothyroxine
2. Normalisation of serum TSH
What is the management of Severe hypothyroidism - Myxoedema coma?
Investigations:
- Serum TSH, T4 and cortisol before thyroid hormone is given
- FBC, serum urea and electrolytes, blood glucose and blood cultures
- ECG monitoring for cardiac arrhythmias
What is the treatment for Myxoedema coma?
- T3 orally or intravenously
- O2
- Gradual rewarming
- Hydrocortisone (in case hypothyroidism due to hypopituitarism)
- Glucose infusion to prevent hypoglycemia
