Endocrinology Flashcards
What antibodies are associated with Graves disease?
TSH receptor antibodies
Also, to a lesser extent
Anti-thyroid peroxidase antibodies
Symptoms of hyperthyroidism
Anxiety and irritability Sweating and heat intolerance Tachycardia Weight loss Fatigue Diarrhoea Sexual dysfunction
Management of hyperthyroidism
Carbimazole Propylthiouracil Radioactive iodine Beta blockers Surgery
Subacute (de quervains) thyroiditis presentation and management
Typically follows a viral infection
Typically causes hyperthyroidism
- painful goitre
- raised ESR
Usually self-limited
Presentation of hypothyroidism
Tiredness, lethargic Low mood Cold-disliking Weight gain Constipation Menorrhagia Decreased cognition and memory Dry skin Fluid retention
Presentation of hyperparathyroidism
Bones - painful
Stones - kidney
Abdominal moans - constipation, nausea and vomiting
Psychiatric groans - fatigue, depression and psychosis
a low dexamethasone test indicates no suppression of cortisol, what does this mean?
Cushing’s syndrome
- dexmeth exerts negative feedback (hypothalamus) reduces CRH and pituitary reduces ACTH in normal response.
Patient has cushings syndrome, on a high dose dex test, cortisol is suppressed, ACTH is suppressed to
Cushings disease
Some negative feedback
Patient has cushings syndrome, on a high dose dex test, ACTH suppressed but cortisol isn’t. What does this mean?
Shows an adrenal adenoma
Cortisol is independent of the pituitary
Patient has cushings syndrome, high dose dex test reveals that cortisol is not suppressed and neither is ACTH
Reveals ectopic ACTH production (SCLC), as production of both is independent of pituitary and adrenal glands
What type of ABG disturbance might be seen in cushings syndrome
Hypokalaemic metabolic alkalosis
Management of cushings
Trans-sphenoid removal of pituitary adenoma
Surgical removal of adrenal tumour
Surgical removal of tumour producing ectopic ACTH
What is primary adrenal insufficiency
Where adrenal glands have been damaged and don’t produce cortisol and mineralcorticoid
- commonly autoimmune
- Addisons
What is secondary adrenal insufficiency?
Result of a loss of ACTH and so cortisol is release from adrenals is less
- pituitary damage
Also chronic steroids - if withdrawn, hypothalamus does not wake up quick enough to release CRH
Electrolyte disturbance in addisons
Hyponatraemia and Hyperkalaemia
Is ACTH high or low in primary adrenal insufficiency?
High
- trying to compensate for lack of negative feedback on cortisol
Is ACTH high or low in secondary adrenal insufficiency?
Low
- reason arsenal glands are not producing cortisol is due to lack of ACTH
Causes of primary aldosteronism
Solitary aldosterone-producing adenoma - CONNS syndrome
Bilaterally adrenal hyperplasia
Rare - adrenal cancer
Features of hyperaldosteronism
HTN Hypokalaemia - muscle weakness, cramps, palpitations Alkalosis Polyuria Polydypsia
Is renin high or low in primary hyperaldosteronism
Low - suppressed by high BP
Is renin high or low in secondary hyperaldosteronism
High - high renin is the cause
Causes of secondary hyperaldosteronism
Where excessive renin stimulates the adrenal gland produces more aldosterone.
Causes of high renin:
- renal artery stenosis
- renal artery obstruction
- heart failure
Does acidosis or alkalosis occur in hyperaldosteronism
Alkalosis (excretion of potassium)
Features of insulinoma
Fasting hypoglycaemia with whipple’s triad:
- symptoms with fasting or exercise
- recorded hypoglycaemia with symptoms
- symptoms relieved with glucose
Tests for insulinoma
Glucose (fasting)
Suppressive test - IV insulin and measure C-peptide production - C-peptide suppressed by insulin normally, does not occur in insulinoma
CT / MRI - pancreas
What should be prescribed in patients awaiting surgery for phaeocytochroma?
Phenoxybenzamine
(Alpha blocker)
Then a beta blocker
Painful goitre, hyperthyroidism following an infection and raised ESR and increased iodine uptake on scan would indicate what?
Subacute thyroiditis
Hypertension and muscle weakness, alkalosis should point towards what?
Hyperaldosteronism
Muscle weakness = hypokalaemia
What diabetic medication causes fluid retention?
Pioglitazone
First line test in acromegaly
IGF-1 levels raised
Then OGTT and GH measurement (no suppression of GH) also impaired glucose tolerance associated with acromegaly
What is diabetes insipidus?
Lack of ADH production (cranial) or
Lack of response to ADH (nephrogenic)
Causes of diabetes insipidus
Nephrogenic:
- drugs - lithium
- mutations in the X chromosome
- intrinsic kidney disease
Cranial:
- idiopathic
- brain infections or surgery or radiotherapy
- head injury
Test for diabetes insipidus
Water deprivation test
What is the osmolality of serum and urine in diabetes insipidus?
Low urine osmolality
High serum osmolality
After 8 hour water deprivation, someone’s urine osmolality is low, then after desmopressin the urine osmolality is high. What does this mean?
Cranial diabetes insipidus
Can still respond to ADH (but don’t produce any)
After 8 hour water deprivation, someone’s urine osmolality is low, then after desmopressin the urine osmolality is low still. What does this mean?
Nephrogenic diabetes insipidus
Kidneys do not respond to ADH
After 8 hour water deprivation, someone’s urine osmolality is high, what does this mean?
Normal
Electrolyte and osmolality abnormalities in syndrome of inappropriate ADH
Hyponatraemia (excessive fluid retention)
High urine osmolality
Peptic ulceration, galactorrhoea, hypercalcaemja should make you think of what?
Multiple endocrine neoplasia type 1
Features of MEN1
Parathyroid - hypercalcaemia
Pituitary- prolactinoma
Pancreas- insulinoma or gastronoma (peptic ulceration)
Features of MEN2a
Parathyroid- hypercalcaemia
Phaeochromocytoma
