Endocrine

Question 1

4/5 uses of Insulin?

Answer 1

For DM: for replacement in type 1 and control in type 2 (where oral hypoglycaemic control is poor). Can also give w/ glucose to treat hyperkalaemia (Insulin drives K+ into cells (hyperkalaemia – short term measure)). Given IV in diabetic emergencies for (hyperglycaemia or ketoacidosis) and perioperative glycaemic control in some DM patients (glucagon for hypoglycaemia).

Question 2

Gliclazide - mechanism?

Answer 2

Sulphonylureas. Mechanism: Lower blood glucose by stimulating pancreatic insulin secretion (patients need residual pancreatic function, as insulin is anabolic may cause weight gain which causes insulin resistance & worsens prognosis)

Question 3

Metformin - mechanism
Most dangerous rare SE?
Warning/interactions?

Answer 3

lowers blood glucose by increasing response (sensitivity) to insulin, (suppressing glucose production and increasing uptake) reduces weight gain (can induce weight loss)

SEs: lactic acidosis (rare but life-threatenting – warn of symptoms: vomiting, SOB etc)

Must be withheld before & after IV contrast media (warn patients to tell Dr if they have X-ray/operation). Caution drugs causing renal impairment e.g. ACEi, NSAIDs and drugs which elevate glucose eg. Prednisolone (measure U&Es)

Question 4

Thyroid produces..?

Answer 4

Thyroid produces T4 (> T3 in tissues) regulating metabolism and growth

Question 5

Thyroid hormones (Thyroxine =T4), Levothyroxine (synthetic T4) (Liothyronine = synthetic T3, quicker so used in emergencies, IV) (PO)

SE?

Answer 5

SEs: excessive dose = hyperthyroidism (GI, cardiac, neurological)

Question 6

Carbimazole ?
Mechanism?
common side effects?

Answer 6

Anti-thyroid drug

Pro-drug converted to methimazole, which prevenets thyroid peroxidase iodinating tyrosine decreasing production of T4 and T3

SEs: rashes, pruritic common (treatment: anti-hystamines)

Question 7

Bisphosphonates – Alendronate aka aledronic acid - use?

SE?

Warning in..?

Interactions?

Answer 7

First line for osteoporosis: osteoporotic fragility fractures – check and replace Ca & vit D before taking

SEs: oesophagitis, hypophsophataemia. Rare but serious SE = osteonecrosis of the jaw (good dental care – Avoid in smokers and dental disease) and atypical femoral fracture

Warning: severe renal impairment, hypocalcaemia, Upper GI disorders.

Interaction: Ca salts + antacids, milk, Fe salts(reduced absorption)

Question 8

What is secondary hyperparathyroidism?

Treat with..?

Answer 8

Secondary hyperparathyroidism is the medical condition of excessive secretion of parathyroid hormone (PTH) by the parathyroid glands in response to hypocalcemia (low blood calcium levels), with resultant hyperplasia of these glands. This disorder is primarily seen in patients with chronic kidney failure.

Treat with Calcium & Vitamin D e.g. calcium carbonate, calcium gluconate

Question 9

Treatment for hyperkalemia?

Answer 9

1. Correct Serious Conduction Abnormalities (Calcium) - Calcium is a very useful agent. It does not lower the serum potassium level, but instead is used to stabilise the myocardium, as a temporising measure. Calcium is indicated if there is widening of QRS (seen in K of over 6.5), sine wave pattern (when S and T waves merge together), or in hyperkalaemic cardiac arrest.
   The ‘cardiac membrane stabilising effects’ take about 15-30mins.

Calcium Chloride
Dose: Calcium Chloride 10% 5-10mL
3 x more potent than
Calcium Gluconate
Complication: severe thrombophlebitis
Calcium Gluconate:
Dose: Calcium Gluconate 10% 5-10mL
Less potent, less irritating to veins
Potential Complications of Calcium administration
Bradycardia, hypotension and peripheral vasodilation
Generally these occur if administered too quickly
Avoid in digoxin toxicity (use magnesium as alternative)

2. Drive Potassium into the Cell:

Insulin & Glucose
Dose: IV fast acting insulin (actrapid) 10-20 units and glucose/dextrose 50g 25-50ml
Insulin drives potassium into cells and administering glucose prevents hypoglycaemia.
Begins to work in 20-30mins reduces potassium by 1mmol/L and ECG changes within the first hour
Sodium Bicarbonate
Dose: 50- 200mmol of 8.4% Sodium Bicarbonate
Bicarbonate is only effective at driving Potassium intracellullarly if the patient is acidotic
Begins working in 30-60 minutes and continues to work for several hours.
Salbutamol
Dose: 10-20mg via nebulizer
Beta 2 agonist therapy lower K via either IV or nebulizer route.

Salbutamol can lower potassium level 1mmol/L in about 30 minutes, and maintain it for up to 2 hours.
Very effective in renal patients that are fluid overloaded

3. Eliminate Potassium From the Body:

Calcium Resonium
Dose: 15-45g orally or rectally, mixed with sorbitol or lactulose
Calcium polystyrene sulfonate is a large insoluble molecule that binds potassium in the large intestine, where it is excreted in faeces
Effects take 2-3 hours

Frusemide
Dose: 20-80mg depending on hydration status
Potassium wasting diuretic. Helps to urinary excrete potassium in conjunction with hydration or fluid overloaded patients
Normal Saline
Used to help renally excrete potassium, by increasing renal perfusion and urinary output. Cautious use in patients with renal & heart failure

Dialysis
Is the gold standard for removing potassium from the body. Provides immediate and reliable removal.
Can lower potassium by 1mmol/L in first hour and another 1mmol/L over the next 2 hours.