Diabetes

Question 1

Compare **diabetes mellitus vs diabetes insipidus **

Answer 1

• diabetes mellitus is a group of metabolic diseases characterised by** high blood sugar levels **over a prolonged period
• diabetes insipidus relates to a lack of ADH or resistance to ADH and its actions

Question 2

what is the **difference **between type 1 vs type 2 diabetes?

Answer 2

• type 1 diabetes is** insulin deficiency** due to pancreatic beta destruction
• type 2 diabetes relates to** insulin resistance in its normal target tissues and beta cell exhaustion**

Question 3

what are the symptoms associated with diabetes mellitus?

Answer 3

• polydypsia - increased thirst
• polyuria - increased urination
• blurred vision
• hyperglyceamia
• glucosuria - glucose in urine

Question 4

Compare the phenotype of type 1 and type 2 diabetes

Answer 4

Type 1 diabetes
* onset in childhood & adolescence **
* prone to ketoacidosis
* autoimmune disease
* absolute insulin deficiency
Type 2 diabetes
* inset after 40 years of age **
* no ketoacidosis
* not autoimmune
* relative insulin deficiency and or **insulin resistance **

Question 5

How is DM diagnosed according to blood glucose (both random and fasting)?

Answer 5

• random plasma glucose greater than 11.1 mmol
• fasting plasma glucose greater than 7.5 mmol
• imapired glucose tolerance test - ie still elevated glucose after 2 hours

Question 6

what is glycosylated hemoglobin?

Answer 6

a form of hemoglobin that is linked to sugar
* can be used to measure the average plasma glucose concentration over 1-3 months

Question 7

Describe type 1 diabetes

Answer 7

• accounts for 5-10% of all cases of diabetes
• early onset - in childhood
• autoimmune destruction of beta cells - and therefore a loss of insulin
• hyperglycema, ketoacidosis and lots of protein breakdown are seen with diabetes type 1

Question 8

what genes are associated with type 1 diabetes mellitus?

Answer 8

the DR clustor of the HLA locus of chromosome 6

Question 9

what are examples of triggers that can cause an autoimmune attack - ie DM type 1?

Answer 9

• environmental triggers eg viral infections coxsackie, mumps, rubella etc

Question 10

what are the metabolic derangments of type 1 diabetes?

Answer 10

• as there is a reduced entry of glucose into the cell due to insulin, leading to hypeglycemia
• insulin deficiency leads to hepatic gluconeogenesis, increasing plasma glucose even further
• as glucose isnt being utilised, FA metabolsim occurs as an alternative source of energy

Question 11

what does excessive FA oxidation lead to?

Answer 11

leads to increased production of ketone bodies

Question 12

what events/ situations where ketoacidosis can occur?

Answer 12

• infection
• trauma
• surgery
• interuption of insulin administeration

Question 13

what is diabetes ketoacidosis?

Answer 13

a serious complication of diabetes that results from** increased levels of ketones** in the blood

Question 14

what is the respiratory compensation of metabolic acidosis?

Answer 14

• CO2 in blood is lowered by hyperventilation will drive the equilibrium away from H+, correcting the acidosis in DKA- this is known as Kussmaul respiration

Question 15

what is the treatment for type 1 diabetes?

Answer 15

• involves a mixture of short and medium or long lasting insulin
• eg glargine lasts for 20-24 hours

Question 16

what is the pathogenesis of type 2 diabetes?

Answer 16

• there is a genetic predisoposition and obesity and life style factors can also cause it
• insulin resistance is seen
• the beta cells in the pancreas produce more insulin as a compensatory mechanism that works initially
• after years, B cell failure occurs and eventually B cell exhaustion and diabetes occurs

Question 17

what are incretins?

Answer 17

group of metabolic hormones that stimulate a decrease in blood glucose levels
* released after eating and stimulates the secretion of insulin from beta cells

Question 18

Describe the **epidemiology of type 2 diabetes **

Answer 18

• estimated prevalence of Type 2 diabetes with age
• obesity is a huge risk factor for type 2 diabetes - lots of obesity in USA, england, austrailia etc

Question 19

why is adipose tissue a metabolically active tissue?

Answer 19

• produces hormones eg adiponectin, leptin, visfatin etc

Question 20

what is the difference between subcutaneous and visceral fat?

Answer 20

• subcutaneous fat is stored just beneath the skin
• visceral fat lies deep within the abdominal walls and surrounds the organs - causes bad health

Question 21

what are examples of drugs that treat type 2 diabetes?

Answer 21

• drugs that improve insulin sensitivity
• drugs that increase insulin secretion
• drugs that reduce glucose GIT absorption

Question 22

what is diabetic retinopathy?

Answer 22

• a diabetes complication that affects the eyes
• caused by damage to the blood vessels that supply the retina
• causes blurred vision

Question 23

what are the 2 types of diabetic retinopathy?

Answer 23

• non proliferative -early stages of disease - increased vascular permeability, without the abnormal growth of blood vessels
• proliferative - advanced form of the disease - abnormal blood vessel growth

Question 24

what is diabetic nephropathy?

Answer 24

• a serious complication associated with diabetes
• damage to renal microvasculature
• more common in type 1 - risk factor is poor glycaemic control
• leading cause of end stage renal disease

Question 25

what are the pathological changes seen in the kidney in diabetic nephropathy?

Answer 25

• glomerular basement membrane thickening
• mesangial cell expansion
• ECM accumulation

Question 26

what is diabetic neuropathy?

Answer 26

• a serious complication associated with diabetes
• involves abnormalities of microvasculature that supplies the peripheral nerves
• this causes an increase in oxidative stress, less NO and leads to vasoconstriction and eventually death of vessels and ischaemia
• diabetic foot is associated with this