ENDOCRINE: Pituitary/ HPA problems incl adrenals andCushings Flashcards
What is Addisons disease?
Primary adrenal insufficiency. Destruction of the adrenal gland or genetic defects in steroid production
What are the symptoms of Addison’s disease?
Very non-specific:
* Nausea
* Abdo pain
* Weight loss
* Fatigue
* Weakness
* Cramps
* Reduced libido
* salt craving
* Dizziness and hypotension due to mineralocorticoid deficiency (aldosterone)
* Hypoglycaemia due to glucocorticoid deficiency
* Pigmentation due to ACTH excess from reduced cortisol
How do you treat an Addisonian Crisis?
1 litre IV fluids - saline over 30-60 mins
100mg IM or IVhydrocortisone
Continue hydrocortisone 6 hourly until pt stable.
After 24hrs = start oral replacement, reducec to maintence over 3-4 days
What is the most common cause of Addison’s disease in the UK?
Autoimmune
What is the relevance of TB to Addison’s disease?
TB can cause Addison’s- most common cause in developing countries
What is the gold standard investigation for Addison’s disease?
What other inv may you do?
ACTH test aka Short Synacthen
Other inv:
* first line - U+Es and serum cortisol (see hyponatraemia, hyperkalaemia and low serum cortisol if unwell)
* renin and aldosterone levels (renin would be high, aldosterone would be low)
* glucose
* blood gas
* adrenal auto-antibodies
* CXR
* CT scan adrenal glands
* MRI brain
In an unwell Addison’s pt, what would blood gas show?
Hyperkalaemic, hyponatraemic hypoglycaemic metabolic acidosis.
Differential diagnosis for adrenal insufficency?
- Chronic fatigue syndrome: Presents with persistent fatigue, cognitive difficulties, and other non-specific symptoms
- Dehydration or septic shock: Hypotension and tachycardia can mimic adrenal insufficiency
- Primary psychiatric illnesses: Depression or other psychiatric illnesses may present with fatigue, decreased appetite, and weight loss.
- Graves disease
How is adrenal insufficency / Addison’s managed?
- replace what is missing - need hydrocortisone (to replace glucocorticoids) and fludrocortisone (to replace mineralocorticoids)
- patient education on sick day rules - carry steriod card and wear medical alert bracelet
- double regular steriod meds dose during any intercurrent illness
- regular screening for complcations - adrenal crisis and osteoporosis.
What are the complications of addison’s disease?
- addisonian crisis
- severe elcetrolyte imbalances
- cardovascular collapse
- hypoglycaemia
- side effects of long term corticosteriod use - osteoporosis, secondary cushings
What are the effects of a prolactinoma in a) women and b) men
a) Women- amenorrhea, galactorrhea and infertility
b) Men- erectile dysfunction, gynocomastia, reduced sex drive and less body hair
What is the most common cause of primary adrenal failure?
Autoimmune, usually have positive adrenal antibodies present
What are the hallmark biochemical features of primary adrenal failure?
Hyperkalaemia, hyponatraemia, raised urea and mild anaemia, hypoglycaemia
Why does ACTH deficiency present like SIADH?
Cortisol deficiency leads to increased ADH secretion
Where is the pituitary gland situated?
In pituitary fossa at the base of the brain
What anatomy lies a) superior and b) laterally to the pituitary gland?
a) Superior - optic chiasm. b) Laterally - cavernous sinus
What nerves/ blood vessels are in the cavernous sinus?
Occulomotor, Trochlear , trigeminal Va, Vb, abducens, internal carotid artery.
How is growth hormone secreted?
Pulsatile manner. Peak pulses during REM sleep
Name the hormones positively and negatively controlling GH
Positive = GHRH. Negative = somatostatin
Describe the adrenal axis
CRH stimulates ACTH release. ACTH release is circadian - peak pulses early in the morning and lowest at midnight. ACTH stimulates cortisol release. Cortisol has negative feedback on ACTH
What are LH and FSH stimulated by and inhibited by?
Pulsatile GnRH stimulates. Testosterone and oestrogen inhibit
What hormones does prolactin inhibit?
LH and FSH - directly inhibit.
What are the 2 ways that pituitary tumours can present?
Compressive - compress surrounding structures - vision, cranial nerves, all hormones can be reduced. (non-functional pituitary tumour).
Excessive hormone production (functional pituitary tumours).
How is prolactin predominantly controlled?
Mostly under negative control by dopamine and weak stimulatory control by TRH