Endocrine Flashcards
What 3 hormones do the adrenals produce
Glucocorticoids cortisol
Mineralcorticoids aldosterone
Sex hormones
Where does aldosterone work
Distal convoluted table → reabsorb Na through Na/K pump.
Stimulates loss of protons and reabsorb Bicarb
Therefore in addisonian rises what abnormalities would you see on ABG
metabolic acidosis (can't get rid of acid and reabsorb bicarb) ↓Na, ↑K
Lack of cortisol causes what serum abnormality
↓glucose
Why do you get mucosal skin pigmentation
ACTH and MTH made from same precursor (refer to osmosis video)
Mgmt of addisonian crisis
- Measure cortisol
- IM hydro 100mg
- 1L 0.9 NaCL over 1 hour
Most common cause of adrenal insufficiency
autoimmune destruction (80%)
What is the defining test for addisons?
Synacthen Test - give
What is Waterhouse Freidrichsen Sybdrome
Actue haemorrhage of adrenal glands → secondary to meningococcal septicaemia
What is Sheehans syndrome
Hypopitutarism cause by ischchaemic necrosis after blood loss in childbirth
Signs of hypokalaemia on ECG
T wave inversion
U waves → looks wavy google it
To types of adrenal ↑
- Cushing syndrome
2. Primary hyperaldostonism
Cushing signs
Muscle wasting + thin extremities, DM, easy bruising …..
Causes of cushings syndrome
- ACTH dependant
• Cushings disease (80%) - pituitary tumour secreting ACTH
• ectopic ACTH production - small cell lung cancer
ACTH Indépendant causes
1) Iatrogenic: steroid
2) adrenal adenoma (5-10%)
Primary hyperaldosteronism 2 causes?
1) Adrenal adenoma (conns syndrome) → cut it out or spironolactone
2) bilateral idiopathic adrenal hyperplasia
Long term steroid mgmt.
1) what to do in infections
2) D+V
1) ↑ during infection - double dose
2) IV or IM dose
Why give fludrocortisone Hydrocortison prednisolone Dexamethasone
1) ↓ glucocortisone, ↑ mineral corticoid
4) ↑ glucocorticoid, ↓ mineralcorticoid
What is a pheochromocytoma?
Catecholamine secreting tumour
Investigations for pheochromocytoma
24 hours collection of urinary metanephrines
Tx for pheochromocytoma? What medication must you give before?
Surgery give alpha blocker before
Main causes of hypercalcaemia
1) Primary hyperparathyroidism
2) Malignancy
How can malignancy cause hypercalcaemia
bone mets
myeloma
PTHrP from squamous cell lung cancer
Mgmt of hypercalcaemia
- Fluids resus
* Bisphosphanates → take 2-4 days to work.
What is trousseaus?
BP cuff sign
What can you see in ECG on hypocalcaemia
prolonged QT interval
Signs of hypocalaemia
CATs go Numb
confusion
arrhythmia
tetany
numbness
Causes of hypocalcaemia
- vit D deficiency (osteomalcai)
- Chronic renal failure
- hypoparathyroidism (e.g. post thyroid/parathyroid surgery)
What is the relationship between Ca and phospahte
PTH
1) ↑ osteoclasts - ↑Ca ↑phos
2) Kidney → activates vit D
3) At nephron PTH causes >Ca and < phosphate → net ↑CA ↓phosphate
What 4 markers help you differentiate causes of hypocalcaemia
Calcium
Phosphate
ALP
PTH
go through table lifted form pass medicine
Refeeding Syndrome → what causes it, what electrolytes deplete
Who can it effect
↓ phos, Ca, Mg - all low in cells but normal in serum
People who have not been eating - e.g bowel surgery, anorexia
Why does hypercalcaemia cause polyuria
Nephrogenic diabetes inscipidous - stops nephron reacting to ADH
ADH - where produced and why?
Produced posterior pit
release in response to
↓ plasma volume,
ADH - where produced and why?
Produced posterior pit
release in response to
↓ plasma volume, ↑drum osmolarity
Why thirsty when hungover
Prevents pituitary releasing ADH - central diabetes incipidous
What is nephrogenic DI
insensitivity to ADH
lithitum, hypercalcaemia, Demeclomyclin
Central DI
Deficiency of ADH
head injury
Inv of diabetes insipidus
• High plasma osmolality, low • urine osmolality
Water deprivation test - deprive of water and measure conc of urine → unable to concentrate urine then give synthetic ADN (vasoopressin) - >
How to test of central of nephrogenic
synthetic ADN (vasoopressin) - > if central will concentrate urine → nephro will stay the same
What is nephrogenic DI
insensitivity to ADH
lithitum, hypercalcaemia, Demeclomyclin
→ polyuria and extreme thirst
Causes
Small cell lung cancer
Any neuro injury
SSRI, tricyclic
Mgmt
Fluid restriction → 1 L a day
Demeclomcycline
Hyponatraemia symtoms
Muscle weakness
spasms/cramps
Seizures
+ feeling crap
How to work out cause
1) Fluid balance examination
2) urine osmolarity
If hypovolaemia and urine osmorlity < 20
D+V, sweating, burn
If hypervolaemia and urine osmorlity < 20
HF, cirrhosis, IV dex
If hypovolaemia and urine osmorlity > 20
Diuretics, addisons,
If euvolaemic and urine osmorlity > 20
SIADH
If correct hyponatraemia too quickly what happens, how quickly should you fix it
central pontine myelinolysis
10mmol/day - 0.9% NaCl - 8 hourly
What do you give for prolactinoma
Dompaine agnoist - bromocriptine
↑ dopamine ↓ prolactin
Test for acromegaly
glucose tolerance test → high glucose, suppresses pituitary
