Type 1 Diabetes Mellitus Flashcards
hyperglycaemia in type 1 diabetes is a result of what pathophysiology?
- Autoimmune condition where insulin-producing beta cells in the islets of langerhan in the pancreas are attacked and destroyed by the immune system - results in partial or complete deficiency of insulin production, resulting in hyperglycemia (because insulin causes cells to take up glucose from the blood)
what are the classifications of diabetes mellitus?
- Type 1 - Type 2 - Hybrid - Other eg. MODY/pancreatic injury - Unclassified - During pregnancy - Type 3C - pancreatectomy
what are the combined causes of type 1 diabetes?
environmental trigger and genetic risk
what are the combined causes of type 2 diabetes?
genetic risk and obesity
what is the name given to autoimmune diabetes that presents later in life?
latent autoimmune disease in adults (LADA)
can T2DM present in childhood?
yes
can diabetic ketoacidosis be a feature of T2DM?
yes
monogenic diabetes can typically present phenotypically as what?
type 1 or type 2 diabetes
how do we measure insulin?
c-peptide as it is the cleavage product of pro-insulin
how are pancreatic beta cells destroyed?
- Presentation of auto-antigen by antigen presenting cells to autoreactive CD4+ T lymphocytes
- CD4+ activate CD8+ lymphocytes
- CD8+ travel to islets and lyse beta cells expressing auto-antigen
- This is exacerbated by release of pro-inflammatory cytokines
- Defects in regulatory T-cells that fail to suppress autoimmunity
Which allele has the largest effect on risk of type 1 diabetes?
HLA-DR allele (human leukocyte antigen)
Give 4 examples of environmental factors that could trigger diabetes type 1
- enteroviral infections
- cow’s milk protein exposure
- seasonal variation
- changes in microbiota
what are the symptoms of type 1 diabetes?
- polyuria
- nocturia
- polydipsia
- blurred vision
- recurrent infections eg. thrush
- weight loss
- fatigue
what are the signs of type 1 diabetes?
- dehydration
- cachexia
- hyperventilation
- smell of ketones
- glycosuria
- ketonuria
lack of insulin leads to which processes?
- proteinolysis –> increased amino acids
- gluconeogenesis –> increased hepatic glucose output
- lipolysis –> increased NEFAs –> beta oxidation —> ketone bodies
what are the complications of hyperglycaemia?
Acute:
- diabetic ketoacidosis
Chronic:
- Microvascular –> retinopathy, neuropathy, nephropathy
- Macrovascular –> ischaemic heart disease, cerebrovascular disease, peripheral vascular disease
what could be the complication of insulin treatment?
hypoglycaemia
what are the options for type 1 diabetes management?
insulin treatment
dietary support/structured educations
technology
transplantation
what are some examples of short-acting insulin taken with meals?
human insulin (actrapid)
insulin analogue (lispro, aspart, glulisine)
what are some examples of background/basal insulin?
- bound to zinc or protamine (neutral protamine hagedorn, NPH)
- Insulin analogue (glargine, determir, degludec)
insulin pump therapy involves continuous delivery of which form of insulin? Into which part of the body?
short-acting into the subcutaneous space
how do you use an insulin pump?
- programme device to deliver fixed units per hour (basal)
- actively bolus for meals
what are the positives of an insulin pump?
Variable basal rates
Extended boluses
Greater flexibility
what dietary advice should you give to those with type 1 diabetes?
- adjust dose of insulin with carbohydrate content of food
- train for carbohydrate counting
- substitute refined carbohydrate foods with complete carbohydrates (low glycaemic index)
How does a closed-loop insulin pump work?
- change in glucose
- real-time continuous glucose sensor
- algorithm to use glucose to calculate insulin requirement
- insulin pump delivers calculated insulin
what is a hybrid closed loop insulin pump?
similar to a closed loop but you must tell it when you want to eat
what are the options for transplantation in type 1 diabetes?
- islet cell transplants from pancreas of deceased donor
- transplant into hepatic portal vein
- life-long immunosuppression
- simultaneous kidney and pancreas transplant (better survival when transplanted with kidneys)
- requires life-long immunosuppression
Downsides of transplantation?
- life-long immunosuppression required
- risk of rejection
- limited availability of donors
which blood tests helps us monitor diabetes control overall?
glycated haemoglobin (HbA1c)
How do we monitor glucose levels?
- capillary (fingerprick) blood glucose monitoring
- continuous glucose monitoring (restricted availability)
hbA1c reflects what time period of glycaemia?
last 3 months
what can affect HbA1c?
- erythropoeisis eg. iron, vit B12 deficiency
- altered haemoglobin
- glycation problems eg. aspirin, vitamin C and E
- erythrocyte destruction eg. antiretrovirals, splenectomy, rheumatoid arthritis
what is used to guide insulin doses?
- self-monitoring blood glucose results at home
- HbA1c results every 3-4 months
what are 3 acute complications of type 1 diabetes?
- diabetic ketoacidosis
- uncontrolled hyperglycaemia
- hypoglycaemia
what can cause diabetic ketoacidosis?
- presenting feature of new-onset type 1 diabetes
- acute illness
- missed insulin doses
- inadequate insulin doses
what levels of pH, ketones, HCO3- and glucose constitute a diagnosis of diabetic ketoacidosis?
- pH <7.3
- ketones increased in blood or urine
- HCO3- less than 15 mmol/L
- glucose > 11 mmol/L
what is the level of glucose that constitutes hypoglycaemia?
<3.6mmol/L
symptoms of hypoglycaemia
Adrenergic
- tremors
- palpitations
- sweating
- hunger
Neuroglycopaenic
- somnolence
- confusion
- incoordination
- seizures
- coma
or NON at all
when does someone usually get no symptoms of hypoglycaemia?
with recurrent hypoglycaemia, body becomes unreactive
how do you relieve hypoglycaemia?
glucose administration
when are the 4 times hypoglycaemia becomes a problem?
- excessive frequency
- impaired awareness (unable to detect low blood glucose)
- nocturnal hypoglycaemia
- recurrent severe hypoglycaemia
what are the risks of hypoglycaemia?
- seizure/coma/death
- impacts on driving
- impacts on emotional well-being
- impacts on day to day function
- impacts on cognition
risk factors for people with type 1 diabetes for hypoglycaemia?
- exercise
- missed meals
- inappropriate insulin regime
- alcohol intake
- lower HbA1c
- Lack of training around dose adjustment for meals
list 5 strategies to support problematic hypoglycaemia?
- indication for insulin-pump therapy
- try different insulin analogues
- revisit carbohydrate counting/structured education
- behavioural psychology support
- transplantation
what is used for the acute management of hypoglycaemia?
- carbohydrates and sugary foods
- glucogel
- 20% glucose IV
- IM injection of glucagon
