Endocrinology Flashcards
What are the 4 hormones involved in appetite regulation?
What do each of them do and detect?
INCREASE SATIETY AND REDUCE APPETITE
Leptin - detects lipids
Insulin - detects carbohydrates
REDUCE SATIETY AND INCREASES APPETITE
Ghrelin and GLP-1 (glucagon-like peptide 1)
Difference between Cushing’s syndrome and Cushing’s disease
Cushing’s syndrome: general term for chronic excessive and inappropriate elevated levels of circulating CORTISOL
Cushing’s disease: excessive cortisol resulting from inappropriate ACTH secretion due to pituitary tumour
CUSHING'S BACKGROUND What releases CRH? Full name? What releases ACTH? Full name? What releases cortisol? Proportion in blood? Bound to? Effects of cortisol (6)
Hypothalamus releases corticotrophin releasing hormone.
Pituitary gland releases adenocorticotrophic hormone.
Zona fasiculata releases cortisol.
95% cortisol binding globulin, 5% free
Increased gluconeogenesis, proteolysis, lipolysis. Increased BP. Anti-inflammatory. Mood and memory.
CUSHING’S SIGNS AND SYMPTOMS
Big 3?
Others?
MOON FACE, OBESITY, BUFFALO HUMP
Mood changes, infection?, thin skin, bruises, osteoporosis, purple striae, acne, increased BP
CUSHING’S DIFFERENTIAL DIAGNOSIS?
Pseudo-Cushing’s syndrome
Caused by alcohol excess - resolves with abstinence
CUSHING’S DIAGNOSIS?
Initial?
First line?
2nd line?
Initial - urine, blood, saliva cortisol
First line - dexamethasone suppression test
(overnight or 48hr)
Second line - ACTH test and dexamethasone injected
ACTH high - pituitary or ectopic
ACTH low - adrenal tumours
CT and MRIs to confirm
CUSHING’S CAUSES?
Exogenous - oral steroids (most common)
Endogenous -
ACTH dependent: pituitary or ectopic
ACTH independent: adrenal tumour
CUSHING’S TREATMENT?
Stops steroids
Surgery on tumours
Medications: inhibit cortisol synthesis, eg METYRAPONE, KETOCONAZOLE, FLUCONAZOLE
ACROMEGALY vs GIGANTISM?
Acromegaly - hormone disorder in adults as a result of excess growth hormone
Gigantism - excess growth hormone in childhood, leading to increased height
ACROMEGALY BACKGROUND
Feedback mechanisms on GH?
Two groupings for GH effects? Examples?
GHRH from hypothalamus stimulates
Somatostatin from muscle, liver, bones inhibits
Direct: increased metabolism and growth increased bone thickness and muscle growth increased insulin resistance increased glucose in blood
Indirect: via IGF-1
increased metabolism, increased cell division and differentiation, prevents cell death
ACROMEGALY EPIDEMIOLOGY AND RISK FACTORS How common? Male vs Female? Age? Specific risk factor
Rare - 3 per million in the UK
Male = Female
Middle age
MEN-1 (multiple endocrine neoplasia)
ACROMEGALY CAUSES
Main?
3 others?
99% of cases: functional pituitary adenoma
also:
ectopic, hypothalamic tumour, MEN-1
ACROMEGALY SIGNS AND SYMPTOMS
List as many as possible.
Note on diagnosis?
Often takes years to diagnose
Headaches increased size of extremities sweating snoring decreased libido amenorrhea skin darkens wide nose deep voice macroglossia
ACROMEGALY COMPLICATIONS
5 examples
Impaired glucose tolerance (40%) Leading to diabetes mellitus (15%) Carpal tunnel syndrome HTN, cardiac problems Colon cancer
ACROMEGALY DIAGNOSIS
3 steps
Test for increased IGF-1 (diagnostic) and GH (non-diagnostic)
Oral glucose tolerance test (OGTT) - glucose should suppress GH
MRI for pituitary adenoma
ACROMEGALY TREATMENT
1st line?
2nd line?
3rd line?
1: Trans-sphenoidal surgery (+radiotherapy?)
2: Somatostatin analogues, eg octreotide or lanreotide
3: GH antagonist (pregvisomant)
ADRENAL INSUFFICIENCY CAUSES
2 categories? Examples?
Primary (ADDISON’S DISEASE)
autoimmune (80%)
TB, metastatic carcinoma, lymphoma, CMV in HIV, adrenal haemorrhage
Secondary
long term steroid use
hypothalamic-pituitary disease (ACTH)
ADRENAL INSUFFICIENCY EPIDEMIOLOGY
How common?
Can it be fatal? Expand on this
Rare - 0.3 per 100,000
Can be fatal - ADDISONIAN CRISIS
untreated w/ bad destruction, leads to dehydration, low BP, tachycardia: possibly death
ADRENAL INSUFFICIENCY SIGNS AND SYMPTOMS?
Split up into 3 categories
- Due to lack of aldosterone
hyperkalaemia, hyponatraemia, hypovolemia, metabolic acidosis, craving salts, NAUSEA, fatigue - Due to lack of cortisol
glucose down, weakness, tiredness, BRONZE PIGMENTATION - Due to lack of androgens
women only: decreased libido and changes/decreases in body hair
ADRENAL INSUFFICIENCY DIAGNOSIS & TREATMENT
First line?
Second line?
1st Blood tests:
sodium, potassium, hormones, etc
2nd ACTH stimulation test:
synthetic ACTH given, measure the cortisol and aldosterone, should increase if healthy
Treatment: Replace hormones
HYDROCORTISONE/PREDNISOLONE (gluco-)
FLUDROCORTISONE (mineral-)
HYPERALDOSTERONISM BACKGROUND
What are the actions of aldosterone? On what cells?
Use these to show signs of hyperaldosteronism.
Principle cell (Na+ and H20 in, K+ out) Hypernatermia, Hypervolemia, Hypokalaemia
Alpha Intercalated Cell (H+ excretion)
Metabolic alkalosis
HYPERALDOSTERONISM EPIDEMIOLOGY AND RISK FACTORS
What is HYPERALDOSTERONISM a rare cause of? How much?
When to check for HYPERALDOSTERONISM?
Rare cause of HTN (less than 1%)
Check for patients with HTN under 35 with no family history
HYPERALDOSTERONISM CAUSES
2 categories?
2 (w/ numbers) x 2
Primary (pathology with adrenal gland)
- adrenal adenoma (CONN’S SYNDROME) (2/3)
- idiopathic bilateral hyperplasia (1/3)
Secondary (pathology elsewhere, increased Renin)
- chronic low BP (heart failure)
- reduced renal perfusion
HYPERALDOSTERONISM CLINICAL FEATURES?
Often?
5.
OFTEN ASYMPTOMATIC
Hypertension, Muscle weakness and paraesthesiae
Polydipsia, polyuria
HYPERALDOSTERONISM DIAGNOSIS
1st tests
2nd tests
Blood tests: U and Es, Aldo, Renin (ARR)
ECG: (hypokalaemia)
24hr aldosterone test (confirmatory)
Adrenal CT scan
HYPERALDOSTERONISM TREATMENT
Main principle:
3 leads from this principle.
Specific medication?
= Treat the cause
- Conn’s (surgery)
- Bilateral Hyperplasia (medication - oral spironolactone, potassium sparing diuretic)
- Heart Failure (normal treatment)
How are pituitary tumours categorised?
3 ways with examples
Size
- microadenoma <1cm, macroadenoma >1cm
Functional (less common - prolactinioma, Cushing’s disease, main cause of Acromegaly)
Non-functional (more common)
Histology
Chromophobe
Acidophil - somatotrophs, lactrotrophs
Basophil - corticotroph, thyrotrophs
3 key signs of a large pituitary tumour
Bilateral temporal hemianopia - starts at top
Palsy of cranial nerves III, IV, VI (eye movement)
CSF rhinorrhoea
What is a pituitary apoplexy?
When do it occur?
A rapid pituitary enlargement due to bleeding into the tumour
Very serious - needs urgent treatment
Can occur as a complication of a pituitary tumour
What is a prolactinoma?
Symptoms? - M vs W
How is it treated? Main example and other
Functional adenoma of lactotrophs that secrete prolactin.
W: Amenorrhea and galactorrhea
M: Low libido and gynecomastia
Treated with BROMOCRIPTINE (main) or CABERGOLINE (dopamine agonists)
Treated with surgery if macroadenoma
What is a craniopharngioma?
Mostly occurs in?
Symptoms?
Tumour orgininates from Rathke’s pouch
Most commonly occurs in children - causes hypopituitarism symptoms and pituitary gland tumour symptoms
What is a neuroblastoma? Who does it occur in? Symptoms? 3 types? Dx and Management?
Tumour of neuroblasts - don’t differentiate properly when forming the adrenal medulla
Usually in infants (less than 5 years old)
Fever, weight loss, sweating, BRUISING AROUND EYES
Differentiated, undifferentiated, poorly differentiated.
CT scan, adrenaline and noradrenaline metabolites (HMA and VMA)
Surgery, chemotherapy, stem cell or bone marrow transplant
What is a pheochromocytoma?
What is the base cell?
Symptoms?
Dx and management?
Rare adrenal gland tumour in the medulla - characterised by the darkening of cells
Chromaffin cells
PHEochromocytoma:
palpitations, headaches, episodic sweating
Test for catecholamines in blood
Surgery
Causes for thyroid nodules?
Multinodular goitre Benign follicular adenoma Thyroid cysts (95% - benign) Thyroid cancers (5%)
Types of thyroid cancers?
Which are the most common?
Which are the most aggressive?
Who do they normally occur in?
DIFFERENTIATED:
papillary (70%) - from follicular cells, young
follicular (20%) - from follicular cells, middle age
medullary (5%) - from calcitonin C cells
Anaplastic - (>5%) from follicular, aggressive, poor prognosis