Diabetes Flashcards
What percentage of diabetic children are type 1 diabetics?
98%
What can contribute to the development of type 1 diabetes?
- FH
- Enteroviral infections
- Cow’s milk protein allergy
- Overnutrition
What is the pathophysiology of type 1 diabetes?
This occurs due to a Type IV hypersensitivity autoimmune reaction which destroys ß-cells, which leads to inability to produce insulin.
How does type I diabetes present?
-
Early
- Triad - polyuria, polydipsia, weight loss
- Enuresis (secondary nocturnal)
- Candida infection
-
Late
- Diabetic ketoacidosis
Why does weight loss occur in diabetes type I?
As glucose cannot enter the cell, cells become starved for energy. This leads to lipolysis and protein breakdown to get energy for cellular metabolism, leading to weight loss. Polyphagia occurs as a result of this.
Why does polyuria occur in diabetes?
The amount of glucose in the blood exceeds the capacity of glucose transporters in the proximal tubule, meaning that glucose is then excreted in the urine. As glucose acts as an osmotic molecule, water is pulled into the urine, thus increaseing the volume of urine produced.
Why does polydipsia occur in diabetes?
This is due a by product of polyuria, as vast amounts of water are being lost in the urine
What are the signs and symtpoms of diabetic ketoacidosis?
- Acetone breath
- Flushed cheeks - ketones
- Vomiting
- Dehydration
- Abdominal pain
- Kusmmaul breathing
- Hypovolaemic shock
- Drowsiness/altered mental state
- Coma
- Death
What is pathogenesis of diabetic ketoacidosis?
Occurs in a state of uncontrolled catabolism. Rapid lipolysis occurs, leading to elevated circulating FFA’s. These are broken down into fatty acyl-CoA, which in turn is broken down into ketone bodies within the mitochondria. As the ketone bodies are acidic (due to carboxylic acid group).
What are the steps of ketone formation?
FFA -> Fatty acyl carnitine -> Acetyl CoA - Acetoacetate.
Acetoacetate is converted either to acetone or ß-hydroxybutyrate
Which ketone body does blood ketone levels look at?
ß-hydroxybutyrate
Why does kussmaul’s breathing occur in diabetic ketoacidosis?
As the blood becomes majorly acidic due to the accumulation of ketone bodies, the respiratory system responds by hyperventilating in an attempt to blow of CO2 and return the pH to normal
Why does abdominal pain and vomiting occur in diabetic ketoacidosis?
This is caused by intestinal ileus caused by acidic ketones.
What else contributes to the acidosis seen in diabetic ketoacidosis?
Lactic acidosis caused by dehydration and poor tissue perfusion
Why does hyperkalaemia occur in diabetic acidosis?
Protons in acidic blood are exchanged for intracellular K+, which increases extracellular K+ levels. As there is a lack of insulin, movement of potassium back into the cell via ATPase is significantly reduced, therefore K+ concentration increases in the blood, which is exacerbated by dehydration and renal failure. K+ is excreted in the urine, and over time this leads to intracellular depletion of K+
What causes dehydration in DKA?
Fluid loss from hyperglycaemia
Vomiting caused by DKA
What problem does dehydration cause in the context of developing DKA?
Dehydration imparis renal function, thus leading to impaired excretion of protons and ketones, thus exacerbating the acidosis
What investigations would you do if you suspected DKA?
- Blood Glucose
- Blood ketones
- Blood gas
- U+E’s
- ECG
- Blood/Urine cultures
What biochemical results would indicate DKA?
- Hyperglycaemia - > 11 mmol/L
- Ketonaemia/Ketonuria - > 3 mmol/L
-
Metabolic acidosis
- pH - <7.3
- HCO3 <15 mmol/L
- Hyper/hypokalaemia - depending on presentation stage - later, more hypo
- Anion gap > 10
How would you manage a child with DKA?
In this order:
-
ABC - Airway, Oxygen 100%, Fluids
- Fluids - bolus if shocked, then maintenance over 48 hours
- Insulin infusion - after fluids have been running for 1 hour
- Potassium replacement
- ACidosis monitoring - bicarb if child shocked
- Re-establish oral fluids, subcut insulin and diet
- Identify the underlying cause of DKA - e.g. infection
When should fluid bolus be given in DKA, and how much fluid should be given as a bolus in DKA?
Only if clinically shocked
One bolus of 0.9% saline at 10ml/kg.
If shock not after this corrected, then call consultant
What is important to remember when giving fluids to children who are dehydrated from DKA?
Don’t rehydrate too quickly as it will lead to cerebral oedema
How would you calculate maintenance fluid for children with DKA?
Hourly rate = (Deficit/48hrs) + maintenance per hour
*Was (48hr maintenance + deficiet - bolus given), but in 2015 BSPED guidlines, above is given
-
Things to remember
-
Deficit percentage based on pH
- Assume 5% if mild - moderate DKA (pH >/=7.1)
- Assume 10% if severe DKA (pH<7.1)
-
Maintenance per hour
- <10kg - 2ml/kg/hr
- 10-40kg - 1ml/kg/hr
- >40kg - fixed fluid of 40 ml/hr
- If >20ml/kg bolus given, subtract volume from deficit + maintenance
-
Deficit percentage based on pH
What concentration of insulin would you give to a child with DKA?
0.1 U/kg/hr IV
-
Consider 0.05 U/kg/hr in:
- Young children,
- Blood glucose <14 mmol/l
- Blood glucose falling >5 mmol/l/h
