Endocrinology Flashcards
How do you determine between Grave’s and De Quervain’s Thyroiditis?
Both are hyperthyroidism presenting with a goitre
Grave’s - non tender goitre
De Quervain’s - painful goitre
Why is exophthalmos specific to Grave’s Disease?
It is a consequence of TPO antibody infiltration and oedema of the periorbital tissues and muscles
Why is the majority of the Hydrocortisone and Fludrocortisone dose given in the earlier half of the day?
Steroids can cause insomnia
What are the biochemical features of Addisonian Crisis?
Hypernatraemia
Hypokalaemia
Hypoglycaemia
PMHx - of using steroids and stopping
What are the causes of raised prolactin levels?
Prolactinoma
Medications
Non-functioning pituitary adenoma
Pregnancy
What is the first line test for diagnosing Cushing’s Syndrome?
Low- dose dexamethasone suppression dose
High-dose helps distinguish the causes
What are the causes of primary adrenal insufficiency? ( Low cortisol, high ACTH)
Addison’s DIsease ( autoimmune )
Infections - TB, fungal, secondary infections to HIV
Infiltration - Amyloidosis, Sarcoidosis
Adrenal Tumours - primary and metastatic
What is Waterhouse-Friderichsen syndrome?
A complication of meningococcal infection, it is adrenal insufficiency secondary to bilateral adrenal haemorrhage
How does a pituitary adenoma cause hypopituitarism?
The compress the normal gland tissue causing it to cease functioning properly
What is the first line test for diagnosing Pheochromocytoma ?
24 hour Urinary metanephrines ( 1st ) and catecholamines
Plasma metanephrines are more specific
How does Carbimazole work?
Decreases the uptake and concentration of iodine by the thyroid. It also prevents the thyroid peroxidase enzyme (TPO) from coupling and iodinating the tyrosine residues on thyroglobulin
What is the first line test for Addison’s Disease?
9am serum cortisol ( low cortisol warrants further investigation)
Then do short SynCATHen test (cortisol levels don’t rise in response to exogenous ACTH)
Confirms primary adrenal insufficiency
Which drugs can cause thyrotoxicosis (high T4) ?
Amiodarone
Can stimulate or damage the thyroid gland ( similar to iodine )
What drugs can cause hypothyroidism?
Amiodarone
Lithium
What are pituitary tumours best visualised on?
Brain MRI
What is the gold standard investigation to clarify a diagnosis of hypopituitarism?
Insulin tolerance test
The stimulates hypoglycaemia, so it can test both ACTH and GH production , these would both increase in normal people eith hypoglycaemia
What are the most common types of thryoid cancer?
Young females - Papillary Thyroid Cancer ( popular)
Elderly female - Thyroid lymphoma ( long life )
How does PTH increase bone ressorbtion?
Binds to osteoblasts, which stimulate osteoclasts via paracrine signalling
What is included in MEN1?
pituitary tumours
parathyroid hyperplasia
pancreatic tumours
What is the first-line management for toxic adenoma or toxic multinodular goitre?
Radioiodine therapy
What is the treatment for patients with an Addisonian Crisis?
FLuid resuscitation
IV Hydrocortisone
How do they Dexamethasone suppression tests work?
Low dose - given at night time. In morning, early morning cortisol levels are not suppressed.
High dose - this will cause suppression of ACTH production by the pituitary adenoma in Cushing’s Disease. However, in ectopic production of ACTH, the cortisol will still not be suppressed as it does not work via a negative feedback cycle.
What is the first line test for suspected Primary Hyperaldosteronism?
Aldosterone/renin ratio ( Aldosterone will be high )
Then to differentiate between causes, a CT of the adrenal glands
Gold standard - s elective adrenal venous sampling can be used ( This shows if its bilateral adrenal hyperplasia because both the left and right adrenal veins will have high aldosterone)
What are the physiological levels of T3, T4 and TSH in the 2nd and 3rd trimester?
T3 and T4 low
TSH normal
What heart problems is hyperthyroidism associated with?
Tachycardia
Atrial FIbrillation
What is the treatment for DKA?
Initially give I.V NaCl Fluid bolus
Give fixed rate insulin infusion an hour later at 0.1 units/kg/hour
What is the treatment for Type 1 Diabetes if the patient becomes hypoglycaemic or hyperglycaemic?
In the community
Hypoglycaemic -
-Consume 15-20g of fast-acting carbohydrate (e.g., glucose tablets, non-diet soda, sweets, fruit juice)
-If patient can’t tolerate oral then do IM Glucagon injection
If in hospital and severe ( seizures, hospital) - Administer 200ml 10% dextrose IV
What are the clinical features of Klinefelter’s?
Delayed puberty
Gynecomastia
Microorchidism
Poor coordination
Muscle weakness
What is the first line treatment for type 1 diabetes?
Basal-Bolus insulin regime
Long acting insulin at night ( e.g Determir )
Short acting insulin 30 minutes before a meal ( e.g Novorapid)
What hormone is most commonly secreted by a Carcinoid Tumour?
Serotonin ( 5HT3)