Disorders of Adrenal Function Flashcards
What is an increased secretion of cortisol called
Cushing’s syndrome
What are the causes of Cushing’s syndrome and how do they cause the increased cortisol secretion
Adnreal cushing’s - increased adrenal cortex activity due to primary cortisol-producing adrenal adenoma
Cushing’s disease - (bengin) pituitary adenoma causes disorders in secretion of ACTH
Non pituitary-adrenal tumours producing ACTH
External causes - prescribed glucocoricoids to treat chronic inflammatory conditions
What are the signs and symptoms of excess coritsol
Increased muscle proteolysis and hepatic gluconeogenesis - hyperglycaemia with polyuria and polydipsia
Increased muscle proteolysis - wasting of proximal muscles (thin arms and legs and muscle weakness)
Increased lipogenesis in adipose - deposition of fat in abdomen, neck and face. Moon-shaped face and weight gain
Purple striae on lower abdomen, upper arms and thighs - catabolic effect on protein structures in skin, easy bruising
Immunosuppressive, anti-inflammatory and anti-allergic reactions cause increased bacterial infection susceptibility
Osteoporosis due to disturbance in Ca metabolism and loss of bone matrix protein
Hypertension due to Na and fluid retention
What is a disease of decreased cortisol secretion called
Addison’s disease
How might Addison’s disease be caused
Diseases of adrenal cortex - i.e. auto-immune destruction
Disorders in pituitary or hypothalamus - decreased ACTH or CRF production
What is Addison’s crisis and how may it present
Life-threatening disease due to adrenal insufficiency
Symptoms:
Nausea, vomiting, extreme dehydration, hypotension, confusion, fever, coma
What are the symptoms of Addison’s disease
Initially non-specific: tiredness, extreme muscular weakness, anorexia, vague abdominal pain, weight loss, occasional dizziness
Extreme muscular weakness and dehydration
Increased skin pigmentation - especially exposed areas, points of friction, buccal mucosa, scars and palmar creases
Decreased BP - Na and fluid depletion
Postural hypotension - fluid depletion
Hypoglycaemic episodes
What clinical tests can be used for adrenocortical function
Measurement of plasma cortisol and ACTH levels
24hr urinaru excretion of cortisol and its breakdown products
Dexamethasone suppression test - dexamethasone suppresses ACTH secretion as it is a potent synthetic steroid
ACTH simtulation test - synacthan normally increases plasma cortisol
What is congenital adrenal hyperplasia
There is a gentic defect in one or more of the enzymes required for synthesis of corticosteroid hormones from cholesterol, meaning cortisol is not produced
Due to lack of cortisol, pituitary is not inhibited by negative feedback so secretes large amounts of ACTH, causing adrenal cortex hyperplasia
What is the most common form of congenital adrenal hyperplasia and what effect can it have
Defect in 21-hydroxylase
Results in less glucocorticoid and mineralocorticoid production
This causes precursor of these hormones to be used in androgen synthesis
This can result in genital ambiguity in female infants and a high rate of Na loss in urine - salt-wasting crisis
What is primary hyperaldosteronism called and what can it be caused by
Conn’s syndrome
Hyperactivity of one or both adrenal glands
Unilateral - adenoma
Bilateral - genetic syndromes
What are the signs and symptoms of Conn’s syndrome
High BP
Occasional muscular weakness and spasms
Tingling sensations
Excessive urination
What do androgens stimulate in males
Growth and development of male genital tract
Height
Body shape
Facial and body hair
Lower voice pitch
Anabolic actions - especially on muscle protein
What effects does over secretion of adrenal androgens have in females
Hirsutism - excessive body hair growth
Acne
Menstrual problems
Virilisation
Increased muscle bulk
Deepening voice
What do oestrogens stimulate in females
Growth and development of female genital tract and breasts
Broad hips development
Accumulation of fat in breasts and buttocks
Body hair distribution
They are weakly anabolic and decrease circulating cholesterol levels
