L17 - Acute complications of diabetes Flashcards
Insulin levels in diabetic keto-acidosis
- Absolute insulin deficiency
Insulin levels in hyperosmolar hyperglycaemia state
- Relative insulin deficiency
What is hyperosmolar hyperglycaemia state
Hyperosmolar hyperglycemic state (HHS) is a complication of diabetes mellitus in which high blood sugar results in high osmolarity without significant ketoacidosis
Symptoms of hyperosmolar hyperglycaemia state
Symptoms include signs of dehydration, weakness, legs cramps, vision problems, and an altered level of consciousness.
Insulin levels in hypoglycaemia
- Relative insulin excess
Effects of insulin deficiency
- Glycogenolysis
- Glucagon, adrenaline(cortisol) release
- Lipolysis and reduced esterification of fatty acids
How does lipolysis and reduced esterification of fatty acids increase hepatic glucose output and cause hyperglycaemia
–> NEFA –> Ketones –> acetone, acetoacetate, hydroxybutyrate
–> glycerol –> gluconeogenesis –> increase in hepatic glucose output and hyperglycaemia
How does proteolysis and reduced uptake of amino acids increase hepatic glucose output and cause hyperglycaemia
Proteolysis and reduced uptake of amino acids –> alanine –> gluconeogenesis –> increase in hepatic glucose output and hyperglycaemia
What causes hyperglycaemia in diabetic ketoacidosis
- Unchecked gluconeogenesis
What causes osmotic diuresis in diabetic ketoacidosis
- Dehydration
What causes ketpsis in diabetic ketoacidosis
- Unchecked ketogenesis
What cases anion-gap metabolic acidosis in diabetic ketoacidosis
- Dissociation of ketone bodies into hydrogen ion and anions
How can insulin deficiency lead to CV collapse
Insulin deficiency –> hyperglycaemia –> glycosuria –> dehydration –> renal failure –> shock –> CV collapse
Insulin deficiency –> lipolysis –> increase in FFAs –> ketones –> acidosis –> CV collapse
Physiological effects of insulin deficiency in adipose tissue
• Increased lipolysis and reduced esterification of fat
• Insulin deficiency
• Glucagon/adrenaline excess
Results in excess FFA and glycerol from breakdown triglycerides
• FFA substrate for hepatic synthesis of ketone bodies
• Acetoacetate/Hydroxybutyrate – strong organic acids
• (Acetone)
• Rate of ketogenesis is linked to rate of gluconeogenesis
• Muscle and brain can utilise ketones as main energy substrate
What causes ketoacidosis
- Ketoacidosis results when ketone body production exceeds rate of utilisation in peripheral tissues (brain and muscle) and renal clearance
How does insulin deficiency give rise to nausea and abdo pain
Lipolysis and reduced esterification of fatty acids –> NEFA –> Ketones –> acidosis –> nausea, abdo pain
How does insulin deficiency cause dehydration
Increased hepatic glucose output and hyperglycaemia –> osmotic diuresis –> dehydration
How is acidosis in diabetic ketoacidosis managed
• Intracellular buffering - H+ / K+ exchange
○ Potassium hydrogen ion pump
• Respiratory compensation – hyperventilation
○ H+ stimulates respiratory centres
○ Breathe off CO2 (H+ + HCO3- H2O + CO2)
• Renal excretion of H+ (slow response)
Electrolyte disturbances in diabetic ketoacidosis
- Potassium depletion - maybe > 250 mmol
- Sodium depletion
- Dehydration
Main differences between cation concentrations between ECF and ICF
- Higher Na+ concentration in interstitial fluid
- Higher K+ concentration in ICF(muscle) - this is due to intracellular buffering - H+/K+ exchange
Age most affected by diabetic ketoacidosis
- Mostly young T1DM
Precipitating causes of diabetic ketoacidosis
- Relative or absolute insulin deficiency
Serum sodium levels in DKA
Normal or low
Blood glucose levels in DKA
Usually <40mmol/l
Serum bicarbonate/pH - DKA
< 14 mmol/l / ph<7.3
Diabetic ketoacidosis - specific precipitating factors
- Infections - pneumonia, urinary tract, viral illnesses, gastroenteritis
- Error/missed insulin administration
- Myocardial infarction
- Previously undiagnosed type 1 diabetes
- Drugs - steroids
Symptoms of diabetic ketoacidosis attributed to hyperglycaemia + dehydration
- Thirst and polyuria
- Weakness and malaise
- Drowsiness
- Confusion
Symptoms of diabetic ketoacidosis attributed to acidosis
- Nausea and vomiting
- Abdominal pain
- Breathlessness
Signs of diabetic ketoacidosis attributed to hyperglycaemia + dehydration
- Dry mouth
- Sunken eyes
- Postural or supine hypotension
- Hypothermia and coma
Signs of diabetic ketoacidosis attributed to acidosis
- Facial flush
- Hyperventilation
- Smell of ketones on breath and ketonuria
Diabetic ketoacidosis - management
- Confirm diagnosis and check for precipitating causes
- Rehydrate and monitor fluid balance (IV fluids - saline with added potassium, consider urinary catheter)
- Lower glucose (intravenous insulin - fixed rate 0.1 unit/kg/hr
- Monitor electrolytes - potassium(and sodium)
- Prevent clots - prophylactic low molecular weight heparin
DKA - other management factors
- Is the patient conscious?
Assess GCS
If concern, call ITU - At risk of aspiration
Consider NG tube - Monitor recovery
Glucose, ketones, pH, potassium - hourly
DKA - recovery
- pH normal, ketones <2+ (urine), vomiting settled
- Resume normal diet
- Switch from intravenous to normal subcutaneous insulin
Hyperosmolar hyperglycaemic state - normal age
Usually > 40 years
Precipitating causes of hyperosmolar hyperglycaemic state
- Previously undiagnosed
- Steroids
- Diuretics
- Sugar
HHS - Serum sodium levels
- Usually high
HHS - blood glucose levels
- Often > 40mmol/l
HHS - Serum bicarbonate/pH
- Normal / pH 7.4
HHS - Serum ketones
0
HHS - mortality
30% (thromboses)
HHS subsequent course
Diet/tablet controlled
DKA - mortality
5% depending on age
DKA - subsequent course
Insulin dependent
HHS - management
• Correct the profound dehydration
- Confirm diagnosis and check for precipitating causes
- Rehydrate & monitor fluid balance
- Iv fluids - saline with added potassium
- Consider urinary catheter
- Lower glucose (once glucose not improving with fluids)
- Intravenous insulin – fixed rate 0.05Unit/kg/hr
- Monitor electrolytes
- Potassium (and sodium)
- Prevent clots
- Treatment low molecular weight heparin
What is hypoglycaemia
- Hypoglycaemia is a biochemical term and exists when blood sugar <4mmol/l but is often used to describe a clinical state
Classification of hypoglycaemia
- Asymptomatic - awake vs sleeping
- Mild symptomatic (patient can treat himself)
- Severe symptomatic (help needed by third party)
- Coma and convulsions
Symptoms of hypoglycaemia - autonomic - sympathomedullary activation
- Sweating, feeling hot
- Trembling or shakiness
- Anxiety
- Palpitations
Neuroglycopenic symptoms of hypoglycaemia
- Dizziness, light-headedness
- Tiredness
- Hunger, nausea
- Headache
- Inability to concentrate, confusion, difficulty speaking, poor coordination, behavioural change, automatism
- Coma and convulsions, hemiplegia
Causes of hypoglycaemia
- Insulin
Inappropriately excessive doses
Not eating, or insufficient carbs - Sulfonylureas
Hypoglycaemia - counter-regulation
- Glucagon, adrenaline, cortisol and GH all have ‘anti-insulin effects’
- Glucagon stimulates glycogenolysis and gluconeogenesis and is probably primary response
- Adrenaline increases glycogenolysis
- GH and cortisol limit glucose disposal in peripheral tissues, but this effect takes several hours so of little benefit acutely
- Sympathetic nerves may also directly activate hepatic glycogenolysis and stimulate glucagon secretion
Treatment of minor episodes of hypoglycaemia
- 2-g carbohydrate as sugary drink, fruit juice, glucose tablets, glucose gels followed by something ‘starchy’ to eat
- Glucose gels
Treatment of hypoglycaemic coma
- IM or IV glucagon 1mg
- IV dextrose 25g (150ml 10% glucose)
How many times can glucagon be given per day
- Glucagon can only be given once daily
- It will not reverse hypoglycaemia in patients with recurrent hypos, anorexia or severe liver disease
Treatment pathway - Mild/moderate hypoglycaemia
Patient conscious, orientated and able to swallow –> give 5 level teaspoons glucose powder in water or 120 mls lucozade or 5 glucose tablets
- Test blood glucose after 15 mins, if <4 mmol/l repeat up to 3 times
- If this has been repeated 3 times, consider 10% glucose IV 100ml/hr or 1 mg glucagon IM
Give long acting carbs (eg 2 biscuits or a slice of bread or next meal if due)
- DO NOT omit subsequent doses of insulin
Treatment pathway - Severe hypoglycaemia
- Patient unconscious/fitting/very aggressive or nil by mouth (NBM) –> Check ABC, stop any IV insulin. If patient suitable for IM glucagon give 1 mg. If not give 10% IV glucose 150ml. Repeat up to 3 times –> Recheck glucose level after 15 mins it should now be above 4mmol/L Give long acting carbs