Diabetes Flashcards
What produces insulin? How does it decrease blood sugar?
- Beta cells in the Islets of Langerhans in the pancreas
- Firstly, it causes cells in the body to absorb glucose from the blood and use it as fuel
- Secondly, it causes muscle and liver cells to absorb glucose from the blood and store it as glycogen (glycogenesis)
What produces glucagon? How does it increase blood sugar?
- Alpha cells in the Islets of Langerhans in the pancreas
- It tells the liver to break down stored glycogen and release it into the blood as glucose (glycogenolysis)
- It also tells the liver to convert proteins and fats into glucose (gluconeogenesis)
What is the normal range for blood glucose concentration?
4.4 - 6.1 mmol/l
What HbA1c result indicates diabetes?
> 48 mmol/mol
What random plasma glucose result indicates diabetes?
> 11 mmol/l
What fasting plasma glucose result indicates diabetes?
> 7 mmol/l
What is the diagnostic criteria for T2DM in a symptomatic vs asymptomatic person?
Symptomatic
- Fasting glucose ≥7 mmol/l
- Random glucose ≥11.1 mmol/l (or after 75g oral glucose tolerance test)
OR if using HbA1c for dx:
- HbA1c ≥48 mmol/mol
Asymptomatic:
- Same as above but on 2 separate occasions
When can HbA1c not be used to diagnose T2DM?
- Conditions resulting in increased red cell turnover (these can cause a raised HbA1c)
- Children
- Expected gestational diabetes
- HIV
- People taking meds that increase glucose e.g. corticosteroids
What’s first, second and third line management of T2DM?
- Metformin
- HbA1c >58 - metformin plus sulfonylurea/DPP-4 inhibotor/SGLT-2 inhibitor/thiazolidinediones
- HbA1c >58 - metformin plus 2 second line drugs OR metformin plus insulin
When should SGLT-2 inhibitors be added to metformin as a first line treatment?
- If the patient has established CVD
- If the patient has chronic HF
- If patient has QRISK >10%
What is the HbA1c target for someone on metformin?
48 mmol/mol
What is the HbA1c target for someone on any drug that may cause hypo (e.g. sulfonylurea) or already on one drug with a HbA1c >58?
53 mmol/mol
What type of drug is metformin?
Biguanide
What is the MOA of metformin?
- Increases insulin sensitivity
- Decreases hepatic gluconeogenesis
Give the main side effects of metformin
- GI upset
- Lactic acidosis
What eGFR is a contraindication to metformin?
<30ml/min
What is the MOA of sulfonylureas?
- Stimulate beta cells to produce insulin
What is an example of a sulfonylurea?
- Gliclazide
What are the main side effects of sulfonylureas?
- Hypoglycaemia
- Wt gain
- Hyponatraemia
What drugs are DPP-4 inhibitors?
-gliptins
What is the role of DPP-4 inhibitors in the management of DM?
- DPP-4 is an enzyme that inhibits hormones called incretins
- Incretins are good and are secreted in response to large meals to lower blood glucose
What are the main side effects of DPP-4 inhibitors?
- Increased risk of pancreatitis
What is an example of a Thiazolidinedione?
- Pioglitazone
What drugs are SGLT-2 inhibitors?
-gliflozins
What are the main side effects of SGLT-2 inhibitors?
- UTI
- Weight loss
What drugs are GLP-1 agonists? When are they indicated?
-tides
- May be used when triple therapy has failed to control diabetes/insulin contra-indicated
Which diabetic meds are given SC instead of oral?
- Insulin
- GLP-1 agonists (-tides)
What are the main side effects of GLP-1 agonists?
- N+V
- Pancreatitis
- Weight loss
What viruses can trigger T1DM?
- Coxsackie B virus
- Enterovirus
What should you always screen new T1DM patients for? Why?
Coeliac disease, the conditions are often linked
What are the key investigations for T1DM?
- Urine dip for glucose and ketones
- Fasting glucose
- Random glucose
What is the diagnostic criteria for T1DM in a symptomatic vs asymptomatic person?
Symptomatic:
- Fasting glucose ≥7 mmol/l
- Random glucose ≥11.1 mmol/l (or after 75g oral glucose tolerance test)
Asymptomatic:
- Same as above but on 2 separate occasions
When is further investigation required for diagnosing T1DM? What does this involve?
- If the clinical presentation includes atypical features e.g. age >50, BMI>25, slow evolution of hyperglycaemia
- C-peptide (low in T1DM)
- Diabetes-specific autoantibodies
How often should type 1 diabetics monitor their blood glucose?
- At least 4 times daily
- Before each meal and before bed
What are the blood glucose targets for type 1 diabetics
a) on waking
b) before meals?
a) 5-7 mmol/l
b) 4-7 mmol/l
What 4 categories of insulin is there?
- Rapid-acting insulin
- Short-acting insulin
- Intermediate-acting insulin
- Long-acting insulin
What is an adverse effect of insulin injecting? What do pts do to manage this?
- Lipodystrophy
- SC fat hardens and prevents normal absorption of insulin
- Cycle injection sites
What insulin regime are patients typically started on? Briefly outline this
- Basal bolus regime
- Long acting insulin injecting in the evening (basal) e.g. Lantus
- Short acting insulin 3 times a day before meals e.g. Actrapid
When should you consider adding in metformin for a type 1 diabetic?
If BMI >25
What is the effect of chronic exposure to hyperglycaemia on blood vessel?
- Causes damage to endothelial cells of blood vessels leading to leaky malfunctioning vessels that are unable to regenerate
What are long term macro-vascular complications of diabetes?
- Stroke
- CAD (major cause of death)
- Hypertension
- Peripheral ischaemia (diabetic foot)
What are long term microvascular complications of diabetes?
- Peripheral neuropathy
- Retinopathy
- Kidney disease (particularly glomerulosclerosis)
What is the management of chronic kidney disease in patients with T2DM?
- ACE-In when albumin-to-creatinine ratio is above 3mg/mmol (in non-diabetics you start an ACE-In when ACR is above 30)
- Add an SGLT-2 inhibitor when the ACR is above 30mg/mmol
What 3 features suggest gestational diabetes
- Large fetus
- Polyhydramnois
- Glucose on urine dip
What is the screening test for gestational diabetes? When is it offered?
- Oral glucose tolerance test
- 24-28 weeks
What are the diagnostic thresholds for diagnosing gestational diabetes?
Either one of…
- Fasting glucose ≥5.6 mmol/l
- 2 hour glucose ≥7.8 mmol/l
REMEMBER cut off for gestational diabetes is 5-6-7-8
What is the management of someone with a fasting glucose <7 mmol/l?
- Diet + exercise for 1/2 wks
- Metformin
- Short acting insulin
What is the management of someone with a fasting glucose >7 mmol/l?
Short acting insulin +/- metformin
What is the management of someone with a fasting glucose >6 mmol/l PLUS macrosomia?
Short acting insulin +/- metformin
What are the target blood glucose levels for women with gestational diabetes/pre-exsisting diabetes:
1) Fasting
2) 2 hours after meals
1) 5.3 mmol/l
2) 6.4 mmol/l
What are some complications of gestational diabetes?
- Neonatal hypoglycaemia
- Macrosomia
- Polyhydramnios
- Polycythaemia
- Preterm birth
- Pre-eclampsia
- Stillbirth
When would you repeat an OGTT postpartum in women with gestational diabetes?
6 weeks postpartum to ensure returned to normal
What is the management of pre-existing diabetes in pregnancy?
- Wt loss if BMI>27
- Stop oral hypoglycaemic agents (apart from metformin) and start insulin
- Folic acid 5mg until 12 wks
- Tight glycemic control
How may someone present with DKA?
- Abdo pain
- Vomiting
- Reduced consciousness
- Kussmaul respiration (deep hyperventilation)
- Acetone-smelling breath
What is the diagnostic criteria for DKA?
- Hyperglycaemia (>11mmol/l)
- Ketosis (blood ketones >3mmol/l)
- Acidosis (<7.3)
What are the 3 most dangerous aspects of DKA?
- Potassium imbalance
- Ketoacidosis
- Dehydration
What blood pH would indicate mild DKA?
<7.3
What blood pH would indicate moderate DKA?
<7.2
What blood pH would indicate severe DKA?
<7.1
What are the levels of …. in DKA?
1. Bicarbonate
2. Creatinine
3. Sodium
- Low (HCO3 is used up trying to buffer ketones)
- Raised (sign of dehydration)
- Normal/raised (due to dehydration)
What affect does insulin have on potassium?
Drives K into cells
What causes potassium imbalance in DKA?
- Without insulin potassium is not driven into cells
- The serum potassium may be high/normal as the kidneys continue to balance the amount of K in the blood and urine
- Total body K is low as no K is stored in cells
What can happen to potassium when insulin treatment of DKA starts? What is a complication of this?
- Severe hypokalaemia as K is driven into cells
- Fatal arrhythmias
When does ketogenesis occur?
When there is insufficient supply of glucose and glycogens stores are exhausted e.g. in prolonged fasting
What causes ketoacidosis in DKA?
- As people with T1DM have low glucose stores, fatty acids are converted into ketones as a source of energy (ketogenesis)
- Initially the kidneys produce bicarb to counteract rising levels of ketone acids
- Overtime ketone acids use up bicarb and blood becomes more acidic
What causes dehydration in DKA?
- Glucose in the urine draws water out with it in a process called osmotic diuresis
- This results in polyuria and severe dehydration
How do you treat DKA? What is the acronym?
FIG PICK:
F – Fluids – IV fluid resuscitation with normal saline (e.g. 1 litre stat, then 4 litres with added potassium over the next 12 hours)
I – Insulin – Add an insulin infusion
G – Glucose – Closely monitor blood glucose and add a dextrose infusion if below a certain level (e.g. 14 mmol/l)
P – Potassium – Closely monitor serum potassium (e.g. 4 hourly) and correct as required
I – Infection – Treat underlying triggers such as infection
C – Chart fluid balance
K – Ketones – Monitor blood ketones (or bicarbonate if ketone monitoring is unavailable)
What is the purpose of given a fixed rate insulin infusion in DKA?
Allows cells to start using glucose again, in turn switching off the production of ketones
What is hyperosmolar hyperglycaemic state?
- Complication of T2DM
- Characterised by hyperosmolality (concentrated blood), hyperglycaemia and the absence of ketones
What are typical symptoms of hypoglycaemia?
Tremor, sweating, irritability, dizziness and pallor
What is the management of severe hypoglycaemia?
IV dextrose and IM glucagon
What are sick day rules for patients on insulin?
- Do not stop insulin due to risk of DKA
- Monitor BM more regularly
What are sick day rules for patients taking oral hypoglycaemic?
- Temporarily stop some oral hypoglycaemics during an acute illness
- Medication may be restarted once the person is feeling better and eating and drinking for 24-48 hours
What is diabetes insipidus characterised by?
1) Decreased secretion of ADH from the pituitary (cranial DI)
OR…
2) An insensitivity to ADH (nephrogenic DI)
What are causes of nephrogenic diabetes insipidus?
- Idiopathic
- Lithium
- Genetic mutations in the ADH receptor gene
- Kidney disease
- Electrolyte disturbances (high calcium or low potassium)
How does diabetes insipidus present?
- Polydipsia
- Polyuria
- Dehydration
- Postural hypotension
How do you investigate diabetes insipidus? What is the diagnostic test
- High plasma osmolality, low urine osmolality
- Water deprivation test (urine osmolality is measured after water deprivation, demopressin aka synthetic ADH is given and urine osmolality is re-measured)
What is the management of diabetes insipidus?
1) Nephrogenic
2) Cranial/central
1) Manage underlying cause, ensure drink plenty of water, thiazide diuretics
2) Demopressin
