Endocrinology Flashcards
What is type 2 diabetes?
A condition where a combination of insulin resistance and reduced insulin production cause persistently high blood sugar levels.
Pathophysiology of type 2 diabetes
-Repeated exposure to glucose and insulin makes the cells in the body resistant to the effects of insulin.
-More and more insulin is required to stimulate the cells to take up and use glucose.
-Over time, the pancreas becomes fatigued and damaged by producing so much insulin, and the insulin output is reduced.
-A high carbohydrate diet combined with insulin resistance and reduced pancreatic function leads to chronic hyperglycaemia which leads to microvascular, macrovascular and infectious complications.
Risk factors for type 2 diabetes
non-modifiable= older age, ethnicity (black african or carribean, south asian), family history
modifiable= obesity, sedentary lifestyle, high carbohydrate (particularly sugar) diet
Presentation of type 2 diabetes
Tiredness, polyuria, polydipsia, unintentional weight loss, opportunistic infections (e.g. oral thrush), slow wound healing, glucose in urine, acanthosis nigricans (associated with insulin resistance)
What is HbA1c?
A blood test that reflects the average glucose level over the previous 2-3 months.
HbA1c for pre-diabetes
48mmol/mol or above
HbA1c for type 2 diabetes
48mmol/mol or above (sample is typically repeated after 1 month to confirm diagnosis)
Management of type 2 diabetes
-a structured education program
-low-glycaemic-index, high fibre diet
-exercise
-weight loss (if overweight)
-antidiabetic drugs
-monitoring and managing complications
First-line medical management of type 2 diabetes
metformin
How does metformin work?
Lowers glucose by inhibiting hepatic gluconeogenesis and opposing the action of glucagon.
Metformin increases insulin sensitivity and decreases glucose production by the liver.
Class of medication = biguanide
Second-line for type 2 diabetes
Sulfonylurea, pioglitazone, DPP-4 inhibitor or SGLT-2 inhibitor
What drug is recommended for type 2 diabetic patients with a QRISK score above 10%, making them fall into the ‘high risk’ category for cardiovascular disease?
SGLT-2 inhibitors
Drug classification of metformin?
Biguanide
Notable side effects of metformin?
-gastrointestinal symptoms, including pain, nausea and diarrhoea
-lactic acidosis (secondary to acute kidney injury)
What suffix do SGLT-2 inhibitors end with?
-gliflozin
Examples= empagliflozin, canagliflozin, dapagliflozin and ertugliflozin
How doe SGLT-2 inhibitors work?
SGLT-2 inhibitors block the action of the sodium-glucose co-transporter 2 protein, causing more glucose to be excreted in the urine.
Loss of glucose in the urine lowers the HbA1c, reduces the blood pressure, leads to weight loss and improves heart failure.
They can cause hypoglycaemia when used with insulin or sulfonylureas.
Side effects of SGLT-2 inhibitors
-increased urine output and frequency
-genital thrush due to lots of sugar passing through the urinary tract
-diabetic ketoacidosis
What is Pioglitazone?
A thiazolidinedione.
It increases insulin sensitivity and decreases liver production of glucose.
Side effects of Pioglitazone
-weight gain
-heart failure
-increased risk of bone fractures
-a small increase in the risk of bladder cancer
What are Sulfonylureas?
Sulfonylureas stimulate insulin release from the pancreas.
Gliclazide is the most common sulfonylurea.
Notable side effects= weight gain and hypoglycaemia
What are incretins?
Incretins are hormones produced by the gastrointestinal tract. They are secreted in response to large meals and act to reduce blood sugar by:
-increasing insulin secretion
-inhibiting glucagon production
-slowing absorption by the gastrointestinal tract
Incretin examples= DPP-4 (dipeptidyl peptidase-4) inhibitors and GLP-1 (glucagon-like peptide-1) mimetics
Describe DPP-4 inhibitors
-Incretin
-DPP-4 inhibitors block the action of DPP-4, allowing increased incretin activity.
Examples= sitagliptin and alogliptin
-side effects= headaches
Describe GLP-1 mimetics
-Incretins
-GLP-1 mimetics imitate the action of GLP-1.
-Examples= exenatide and liraglutide
-They are given as subcutaneous injections
-Liraglutide can also be used for weight loss in non-diabetic obese patients.
-Side effects= reduced appetite, weight loss, gastrointestinal symptoms, including discomfort , nausea and diarrhoea.
What are the different types of insulin
Rapid-acting insulins (e.g., NovoRapid) start working after around 10 minutes and last about 4 hours.
Short-acting insulins (e.g., Actrapid) start working in around 30 minutes and last about 8 hours.
Intermediate-acting insulins (e.g., Humulin I) start working in around 1 hour and last about 16 hours.
Long-acting insulins (e.g., Levemir and Lantus) start working in around 1 hour and last about 24 hours or longer.
Combinations insulins contain a rapid-acting and intermediate-acting insulin. In brackets is the ratio of rapid-acting to intermediate-acting insulin:
Humalog 25 (25:75)
Humalog 50 (50:50)
Novomix 30 (30:70)
What are the key complications of type 2 diabetes?
-infections (preiodontitis (gum disease), thrush and infected ulcers)
-diabetic retinopathy
-peripheral neuropathy
-autonomic neuropathy
-chronic kidney disease
-diabetic foot
-gastroparesis (slow emptying of the stomach)
-hyperosmolar hyperglycaemic state)
What drug is used as first-line to manage hypertension in patients of any age with type 2 diabetes?
ACE inhibitors
ACE inhibitors are started in type 2 diabetics with ………. when the albumin-to-creatinine ratio (ACR) is above 3 mg/mmol (as opposed to 30 mg/mmol in patients without diabetes).
Chronic kidney disease