Endocrine Gap Flashcards
Acromegaly diagnostic test
Initial Test: Serum IGF-1 levels
Confirmatory: OGTT suppression of GH is used for confirmation
Inv for Subacute Thyroiditis
Investigations
thyroid scintigraphy: globally reduced uptake of iodine-131
Acromegaly Rx
- Trans-sphenoidal surgery is the first-line treatment for acromegaly in the majority of patients.
- If a pituitary tumour is inoperable or surgery unsuccessful then medication may be indicated:
First line:
somatostatin analogue
directly inhibits the release of growth hormone
for example octreotide
effective in 50-70% of patients
Negative Acute phase proteins
albumin
transthyretin (formerly known as prealbumin)
transferrin
retinol binding protein
cortisol binding protein
Patient with features of addissons diseaase but normal short synacthen test. what to do next?
Performing an insulin tolerance test is the most appropriate next investigation. The insulin tolerance test is considered the gold standard for assessing secondary adrenal insufficiency and is the most appropriate next step.
—– is the most important modifiable risk factor for the development of thyroid eye disease
smoking is the most important modifiable risk factor for the development of thyroid eye disease
——- is the most common complication of thyroid eye disease
Exposure keratopathy
this is the most common complication of thyroid eye disease
Which drug can cause hypothyroidism/Hyperthyroidism
Amiodarone
Toxic Multinodular Goitre Investigations
- Nuclear scintigraphy reveals patchy uptake
- The treatment of choice is radioiodine therapy
Lab findings in sick euthyroid
T3, T4 low
TSH low or more than normal
Thyroid scintigraphy finding of Subacute (De Quervain’s) thyroiditis
thyroid scintigraphy: globally reduced uptake of iodine-131
Name of Thyroid Cancers
PFEMALE
Papillary: most common. young woman
Follicular
Medullary: associated with MEN2
Anaplastic: can cause pressure symptoms
Lymphoma: associated with Hashimotos
Which drugs have interaction with Thyroxine
iron, calcium carbonate
absorption of levothyroxine reduced, give at least 4 hours apart
Choice of antithyroid drugs during pregnancy
Propylthiouracil has traditionally been the antithyroid drug of choice
What happens during pregnancy in terms of thyroid physiology
In pregnancy, there is an increase in the levels of thyroxine-binding globulin (TBG). This causes an increase in the levels of total thyroxine but does not affect the free thyroxine level.
DPP4 inhibitors
Sitagliptin
Saxagliptin
Linagliptin
Alogliptin
Vildagliptin
Sulfonylureas
Glibenclamide (also known as Glyburide)
Glipizide
Gliclazide
Glimepiride
How to adjust Metformin in Ramadan
for patients taking metformin the expert consensus is that the dose should be split one-third before sunrise (Suhoor) and two-thirds after sunset (Iftar)
Higher-than-expected levels of HbA1c seen in
Vitamin B12/folic acid deficiency
Iron-deficiency anaemia
Splenectomy
Lower-than-expected levels of HbA1c are seen in
Sickle-cell anaemia
GP6D deficiency
Hereditary spherocytosis
Haemodialysis
Antibodies seen in Graves
Autoantibodies
TSH receptor stimulating antibodies (90%)
anti-thyroid peroxidase antibodies (75%)
Graves’ disease is an autoimmune thyroid disease in which the body produces IgG antibodies to the thyroid-stimulating hormone (TSH) receptor.
Major complication of Carbimazole
the major complication of carbimazole therapy is agranulocytosis
—– is a known feature of chronic hypocalcaemia.
Cataract formation is a known feature of chronic hypocalcaemia.
if the cause of hypoglycaemia is not clear then a combination of —— and —- levels can be measured
if the cause of hypoglycaemia is not clear then a combination of serum insulin and c-peptide levels can be measured
Inv for Insulinoma
supervised, prolonged fasting (up to 72 hours)
Bartter’s syndrome results from —-, and results in —-?
defective chloride absorption at the Na+ K+ 2Cl- cotransporter (NKCC2) in the ascending loop of Henle. It should be noted that it is associated with normotension (unlike other endocrine causes of
impaired fasting glucose (IFG) - due to —— resistance
impaired glucose tolerance (IGT) - due to ——- resistance
impaired fasting glucose (IFG) - due to hepatic insulin resistance
impaired glucose tolerance (IGT) - due to muscle insulin resistance
—– is the most common causes of primary amenorrhoea
gonadal dysgenesis (e.g. Turner’s syndrome) - the most common causes
Cause of Bartter’s Syndrome
Bartter’s syndrome is an inherited cause (usually autosomal recessive) of severe hypokalaemia due to defective chloride absorption at the Na+ K+ 2Cl- cotransporter (NKCC2) in the ascending loop of Henle.
Loop diuretics work by inhibiting NKCC2 - think of Bartter’s syndrome as like taking large doses of furosemide
Lab inv for Conn, Liddle and RAS
Renin and Aldosterone;
Both High= Bilateral Renal Artery Stenosis
Both Low=Liddle Sydrone (L for Low)
Renin Low,Aldo High=Conn’s
Rx of Liddle
Treatment is with either amiloride or triamterene.
Liddle’s syndrome results from a gain-of-function mutation leading to persistent activation of epithelial sodium channels (ENaC) in the distal convoluted tubule
Liddle pathophysiology
Mutation in the epithelial Sodium channels
Bartter presents as
usually presents in childhood, e.g. Failure to thrive
polyuria, polydipsia
hypokalaemia
normotension
weakness
Congenital Adrenal Hyperplasia is diagnosed as
ACTH stimulation testing is used to confirm the diagnosis
evaluates the adrenal gland’s response to ACTH, with abnormal increases in 17OHP indicating CAH
M/A of Dpp4
Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that increases incretin levels by inhibiting their breakdown
Familial hypercholesterolaemia (FH) genetics
- autosomal dominant
- results in high levels of LDL-cholesterol which, if untreated, may cause early cardiovascular disease (CVD). - FH is caused by mutations in the gene which encodes the LDL-receptor
Low K, Hypertension
The differential for hypertension with low potassium includes Conn’s, Cushing’s, renal artery stenosis and Liddle’s. The first step in this case should be further simple investigations. Quantifying the renin and angiotensin levels will help to distinguish the cause here, before going on to more specialised tests.
Cushing’s and Conn’s would be associated with a high aldosterone and a low renin, renal artery stenosis would be associated with a high renin and aldosterone, Liddle’s is associated with a low renin and aldosterone.
