Urinalysis And Glocose Tolerance Testing Flashcards
What is the role of Glucagon?
- Stimulates the production of glucose in the liver (glucose o genesis and glycogenolysis)
- Increases ketogenesis in the liver
- Influences the breakdown of protein and fats into glucose during fasting
How does glucose control glucagon secretion?
Low glucose level is stimulatory
High glucose level is inhibitory
What happens in type 1 and type 2 diabetes?
Type 1- insulin is not produced
Type 2- the response to insulin is diminished
What is the oral glucose tolerance test (OGTT)?
Used to diagnose suspected type 2 diabetes as well as other blood glucose related disorders
- Measures the levels of hyperglycaemia in the blood of a patient
- Allows for monitoring of its eventual fall as it is moved into tissues (by insulin mediated action)
- Measured in either: blood, plasma or serum glucose
How is glycemic load measured?
- Tale a baseline reading (0 mins)
- Eat/drink sugar source (banana, sweets, lucosade)- 75g
- Record blood glucose every 15 mins
What is the difference between blood and plasma glucose levels?
- Estimation of whole blood glucose levels are usually 10-15% lower than plasma glucose alone
- The glucose concentration in the water that makes up plasma is equal to that of RBC
- Plasma has higher greater water content than RBC = exhibits higher glucose levels than whole blood
(Plasma has a higher water content that whole blood, so more dissolved glucose in plasma compared with whole blood)
What would normal glucose tolerance test results look like?
- After eating (glucose meal), plasma glucose rises slowly (intestinal uptake of glucose)
- As a result plasma insulin rises sharply
- The difference between the insulin responses is due to the incretin effect of oral glucose ingestion (increased stimulation of insulin secretion elicited by oral as compared with IV administration of glucose under similar plasma glucose levels- type 2 diabetes lose this effect)
What would type 1 diabetes glucose tolerance test results look like?
- The same oral glucose intake causes plasma glucose to rise to a higher level and remain high for a longer time
- Diabetes diagnosis is made if the plasma glucose is about 200mg/dL at the second hour
Factors that may impact blood glucose results:
- Conditions other than diabetes (Cushing’s syndrome, pancreatitis and certain tumours)
- Pregnancy
- Too much/not enough food
- Not being active enough/being too active
- Side effects from medications
- Illness/infection
- Menstrual cycle
Urine components: Glucose
- Water soluble sugar molecule
Absence in urine is normal
Presence is known as glycosuria (causes: diabetes mellitus, renal tubular disease, some diabetic medications)
Urine components: Ketones
- The breakdown product of fatty acid metabolism
Absence in urine is normal
Presence suggests increased fatty acid metabolism (occurs during starvation, in conditions such as diabetic ketoacidosis)
Urine components: Specific gravity
- Indicates amount of solute dissolved in urine
Normal range: 1.002-1.035 mOsm/kg
Causes of low (conditions that result in the production of dilute urine)
Causes of raised (dehydration, glycosuria, proteinuria)
Urine components: Blood
Indicates the amount of: RBC, haemoglobin and myoglobin
Absence of the above is normal
Presence may indicate (UTI, renal stones, injury to urinary tract, myoglubinurea, nephrotic syndrome, malignancy of urinary tract)
Urine components: pH
- Represents acidity of urine
Normal range: 4.5-8
Causes of low pH (starvation, diabetic keoacidosis, other conditions causing metabolic acidosis- eg. Sepsis)
Causes of raised pH (UTI, conditions that cause metabolic alkalosis, medications)
Urine components: Protein
- Indicates the level of protein present in urine (proteinuria)
Absence is normal
Causes of presence (nephrotic syndrome, chronic kidney disease)
