Basics Endocrinology Flashcards
What is Addison’s?
- autoimmune destruction adrenal glands
- most common cause hypoadrenalism
- reduced cortisol and aldosterone
- hyponatraemia, hyperkalaemia, hyperpigmentation, vitiligo, hypoglycaemia, hypotension, salt craving, weight gain etc.
How do you investigate Addison’s?
- ACTH stimulation test
- plasma cortisol 30 min before and after 250 ug IM synacthen
- electrolyte abnormalities
How do you manage an Addisonian crisis?
- hydrocortisone 100mg IM or IV
- 1 litre normal saline or dextrose if hypoglycaemic
- continue hydrocortisone 6 hourly until stable
Management of Addison’s
glucocorticoid and mineralocorticoid replacement therapy (hydrocortisone and fludrocortisone)
What is Acromegaly?
- excess GH
- 95% secondary due to pituitary adenoma
- coarse facial features, prognathism, interdental spaces, increase shoe size, sweat gland hypertrophy, features of primary tumour
How do you investigate acromegaly?
- GH vary so not diagnostic
- serum IGF-1 levels first line
- OGTT can help to confirm
- Pituitary MRI
How do you manage acromegaly?
-transphenoidal surgery if not: -somatostatin analogue e.g. octreotide -GH receptor antagonist e.g. pegvisomant -dopamine agonist e.g. bromocriptine
What is Bartter’ syndrome?
- autosomal recessive severe hypokalaemia due to defective chloride absorption at NKCC2 in ascending loop of Henle
- normotensive
- failure to thrive in childhood, polyuria, polydipsia, hypokalaemia, normotension and weakness
What are the causes of congenital adrenal hyperplasia?
- autosomal recessive disorders
- high ACTH in response to low cortisol
- 21-hydroxylase deficiency
- 11-beta-hydroxylase deficiency
- 17-hydroxylase deficiency
What investigations for Cushing’s
- hypokalaemic metabolic alkalosis
- impaired glucose tolerance
- ectopic ACTH leads to hypokalaemia
- insulin stress test to distinguish pseudo
- confirm with overnight dexamethasone suppression test and 24 hour urinary free cortisol
Explain the difference in results between normal, Cushing’s syndrome, disease and ectopic ACTH with low dose dexamethasone, high-dose and ACTH levels:
- normal: decrease, decrease, no change
- syndrome: no change, no change, decrease
- disease: no change, decrease, increase
- ectopic ACTH: no change, no change, increase
What is Liddle’s syndrome?
- rare autosomal dominant cause of hypertension
- hypokalaemic alkalosis
- disordered increased sodium reabsorption
- treat with amiloride or triamterene
MEN type I
-parathyroid
-pituitary
-pancreas
(adrenal and thyroid)
MEN1 gene
MEN type II
-medullary thyroid cancer
-parathyroid
-phaeochromocytoma
RET oncogene
MEN type III
-medullary thyroid cancer
-phaeochromocytome
-marfanoid body, habits, neuromas
RET oncogene
What is a myxoedema coma and how do you treat it?
- decompensated hypothyroidism
- confusion and hypothermia
- IV thyroid replacement, IV fluids, IV corticosteroids, electrolyte imbalance correction
What is a phaeochromocytoma?
- rare catecholamine secreting tumour
- 10% familial: MEN type II, neurofibromatosis, von Hippel-Lindau
- causes hypertension, episodic headaches, palpitations, sweating and anxiety
How do you test for phaeochromocytoma?
- 24hr urinary collection of metanephrines
- replaced 24hr collection of catecholamines
How do you treat phaeochromocytoma?
- surgery
- before surgery, stabilise with alpha blocker (phenoxybenzamine) and beta blocker (propranolol)
What are some typical symptoms of pituitary adenomas?
- symptoms due to excess or depletion of hormone
- stretching of dura causing headaches
- compression of optic chasm causing bitemporal hemianopia
What are the investigations for pituitary adenomas?
- pituitary blood profile: HG, prolactin, ACTH, FH, LSH, TFTs
- formal visual field testing
- MRI brain with contrast
How can you treat pituitary adenomas?
- hormonal therapy (bromocriptine)
- surgery if progression in size
- radiotherapy
What are the features of primary hyperaldosteronism and what is it caused by?
- adrenal adenoma, bilateral idiopathic adrenal hyperplasia and adrenal carcinoma
- hypertension, hypokalaemia, alkalosis
What are the investigations for primary hyperaldosteronism?
- plasma aldosterone/renin (increased aldosterone, decreased renin due to negative feedback)
- adrenal venous sampling
- CT abdomen