Week 9 - Endocrine Flashcards
Define Diabetes Mellitus?
Metabolic disorder of multiple aetiology characterised by chronic hyperglycaemia with disturbances of carbohydrate, protein & fat metabolism resulting from defects in insulin secretion, insulin action, or both
List 3 characteristics of diabetes mellitus?
- Glycosuria - Depletion of Energy Stores
- Glycosuria - Osmotic Diuresis
- Glucose Shifts - Swollen Ocular Lenses
List the 5 symptoms associated with glycosuria in diabetes mellitus?
- Tired
- Weak
- Weight loss
- Difficulty concentrating
- Irritability
List 6 symptoms of glycosuria osmotic diuresis in diabetes mellitus?
- Polyuria
- Polydipsia (excessive drinking)
- Thirst
- Dry mucous membranes
- Reduced skin turgor
- Postural hypotension
What is the symptom for glucose shifts in diabetes mellitus?
Blurred vision
List the 3 types of presentations of diabetes mellitus?
- Ketone production
- Depletion of energy stores (ie. muscle)
- Complications (T2DM)
List the 7 symptoms of ketone production is diabetes mellitus?
- Nausea
- Vomiting
- Abdominal pain
- Heavy/rapid breathing
- Acetone breath
- Drowsiness
- Coma
List the 4 symptoms of depletion of energy stores (ie. muscle) in diabetes mellitus?
- Weakness
- Polyphagia (excessive eating)
- Weight loss
- Growth retardation in young
List the 4 complications of T2DM?
- Macrovascular
- Microvascular
- Neuropathy
- Infection
What is the normal fasting & 2hr plasma glucose?
- Fasting: <7
- 2hr: <7.8
What is the IGT (Impaired glucose tolerance) fasting & 2hr plasma glucose?
- Fasting: <7
- 2hr: 7.8-11.0
What is the WHO criteria for a diagnosis of diabetes mellitus?
- Fasting plasma glucose >7.0 mmol/L
- Random plasma glucose >11.1 mmol/L
- 1 abnormal values diagnostic if symptomatic
- 2 abnormal values if diagnostic if asymptomatic
What should the HbA1c be for a diagnosis of diabetes?
6.5% or 48 mmol/mol
What should diabetes NOT be diagnosed based on?
NOT be diagnosed on the basis of glycosuria or a BM stick
When is OGTT only required for?
Diagnosis of Impaired fasting glycaemia (IFG) or Gestational diabetes mellitus (GDM)
List the 5 classifications of diabetes?
- Maturity Onset Diabetes of the Young (MODY)
- T2DM
- Secondary DM
- Latent Autoimmune Diabetes of Adulthood (LADA)
- T1DM
What does SAID stand for?
Severe autoimmune diabetes
What does SIDD stand for?
Severe insulin-deficient diabetes
What does SIRD stand for?
Severe insulin-resistant diabetes
What does MOD stand for?
Mild obesity-related diabetes
What does MARD stand for?
Mild age-related diabetes
What are the 2 types of primary diabetes?
- Type 1 DM
2. Type 2 DM
What is Type 2 diabetes mellitus a combination of?
Insulin resistance & insulin deficiency
Describe the presentation of type 1 diabetes mellitus?
- <30 usually
- Lean patient
- Weeks of symptoms
- Northern European higher risk
Describe the pathogenesis of type 1 diabetes mellitus?
- HLA DR3 or DR4 in 90%
- Autoimmune
Describe the clinical presentation of type 1 diabetes mellitus?
- Insulin Deficiency +/- Ketoacidosis
- Dependent on Insulin for survival
Describe type 1 diabetes mellitus biochemically?
C Peptide Innappropriate/negative
Describe the presentation of type 2 diabetes mellitus?
- > 30 usually
- Overweight patient
- Months/Years of symptoms
- Asian, African, Polynesian & American Indian higher risk
Describe the pathogenesis of type 2 diabetes mellitus?
- No HLA links
- No immune disturbance
Describe the clinical presentation of type 2 diabetes mellitus?
- Partial Insulin Deficiency at presentation +/- Hyperosmolar state
- May need Insulin
Describe type 2 diabetes mellitus biochemically?
C peptide positive
What does a plasma ketone reading of below 0.6mmol/L indicate?
Normal range & no action is needed
What does a plasma ketone reading of 0.6-1.5mmol/L indicate?
- Development of a problem that may require medical assistance
- Call your healthcare team
What does a plasma ketone reading of above 1.5mmol/L indicate?
- In the presence of hyperglycaemia indicates high risk of DKA
- Contact healthcare team immediately for advice
What are the islet autoantibodies?
Markers of autoimmune process associated with T1DM
What are islet autoantibodies present in?
- 80% of T1DM if combination of glutamic acid decarboyxylase (GAD) & insulinoma-associated antigen -2 (IA2) measured (<1% of MODY)
- Some patients with T2DM have positive antibodies (progress more quickly to insulin)
When are islet autoantibodies most useful in T2DM?
3-5 years from diagnosis (overlap with T2DM/MODY before, especially in obese)
Describe C-peptide?
- Secreted in equimolar concentrations to insulin
- Useful marker of endogenous insulin secretion
When is a C-peptide measurement most useful?
3-5 years from diagnosis (overlap with T2DM/MODY before especially in obese)
Where can you measure C-peptide?
Blood or urine (urine C peptide/creatinine ratio)
What % of diabetes mellitus is type 1?
10%
What is the definition of type 1 diabetes?
Chronic, progressive metabolic disorder characterised by hyperglycaemia & the absence of insulin secretion
Describe the pathogenesis of type 1 diabetes mellitus?
- Results from autoimmune destruction of the insulin-producing beta cells in the islets of Langerhans
- Occurs in genetically susceptible subjects & is probably triggered by 1+ environmental agents
List the 7 steps of type 1 diabetes mellitus disease progression?
- Genetic risk
- Immune activation- beta cells are attacked
- Immune response- development of single autoantibody
- Stage 1- normal blood sugar, => autoantibodies
- Stage 2- abnormal blood sugar, >2 autoantibodies
- Stage 3- clinical diagnosis => 2 autoantibodies
- Stage 4- Long standing T1D
If you have a relative with diabetes mellitus, you are at a ____ greater risk of developing T1D?
15x
List the 7 possible factors which reports have found to increase the risk of T1DM (no associations have been verified and many have been contradicted)?
- Viral infections (enterovirus)
- Immunisations
- Diet (cow’s milk)
- Higher socioeconomic status
- Obesity
- Vitamin D deficiency
- Perinatal factors ie. maternal age, history of preeclampsia, neonatal jaundice & low birth weight (reduced risk)
What is the lifetime risk of developing T1DM with an affected monozygotic twin?
- 30% within 10yrs of diagnosis of the twin
- 65% concordance by age 60yrs 5% of DM
What % of diabetes mellitus is type 2?
90%
What is the definition of type 2 diabetes mellitus?
Chronic, progressive metabolic disorder characterised by hyperglycaemia, insulin resistance & relative impairment of insulin deficiency
Describe the pathogenesis of type 2 diabetes mellitus?
- Common with a prevalence that rises markedly with increasing levels of obesity
- Most likely arises through a complex interaction among many genes & environmental factors
Describe the epidemiology of type 2 diabetes mellitus?
- 39% have at least 1 parent with the disease
- Prevalence varies remarkably among ethnic groups living in the same
What % of diabetes mellitus is MODY?
1-2% (often unrecognised)
What is MODY caused by?
- Caused by change in a single gene (monogenic)
- Autosomal dominant (50% chance of inheriting)
What does MODY stand for?
Maturity onset diabetes of the young
What are the 3 main features of MODY?
- Often <25yrs onset
- Runs in families from 1 generation to next
- Managed by diet, oral antihyperglycemic agents (OHAs), insulin (not always)
What does IDDM stand for?
Insulin dependent diabetes mellitus
List the 5 clinical features of Latent Autoimmune Diabetes of Adulthood (LADA)?
- Onset usually >25
- 0 parents affected
- Rarely obese
- Variable insulin treatment, usually within months or years of diagnosis
- Polygenic inheritance
- GAD autoantibodies
List the 5 clinical features of Early Onset Type 2 Diabetes?
- Onset 25-40
- 2 parents affected
- Obesity is common
- No insulin treatment initially
- Polygenic double gene dose inheritance
- No GAD autoantibodies
List the 5 clinical features of Maturity Onset Diabetes of the Young (MODY)?
- Onset <25
- 1 parent affected
- Rarely obese
- No insulin treatment initially
- Monogenic autosomal dominant inheritance
- No GAD autoantibodies
What is gestational diabetes mellitus (GDM)?
Carbohydrate intolerance with onset, or diagnosis, during pregnancy
List 3 risk factors for gestational diabetes mellitus (GDM)?
- High BMI
- Previous macrosomic baby/ gestational diabetes
- Family history/ethnic prevalence of diabetes
What should all pregnant women with risk factors of gestational diabetes mellitus have?
OGTT (oral glucose tolerance test) at 24 to 28 weeks
What is the internationally agreed criteria for gestational diabetes using 75g OGTT?
- Fasting venous plasma glucose ≥ 5.1 mmol/l, OR
- 1hr value ≥ 10 mmol/l, OR
- 2hrs after OGTT ≥ 8.5 mmol/l
List the 7 causes of secondary diabetes?
- Genetic Defects of beta-cell function
- Genetic defects in insulin action
- Disease of exocrine pancreas
- Endocrinopathies
- Immunosuppressive agents
- Anti Psychotics
- Genetic syndromes associated with DM
Give 4 examples of Diseases of the exocrine pancreas which can cause secondary diabetes?
- Pancreatitis
- Carcinoma
- Cystic fibrosis
- Haemochromatosis
Give 3 examples of endocrinopathies which can cause secondary diabetes?
- Acromegaly
- Cushings
- Phaeochromocytoma
Give 3 examples of immunosuppressive agents which cause secondary diabetes?
- Glucocorticoids
- Tacrolimus
- Ciclosporin
Give 5 examples of genetic syndromes associated with secondary diabetes?
- Down’s Syndrome
- Friedreich’s Ataxia
- Turner’s
- Myotonic Dystrophy
- Kleinfelter’s Syndrome
Describe the production & release of insulin?
- Produced in beta cells (75% of the islets of Langerhans of the pancreas)
- Released by exocytosis into the portal venous system which leads it directly to the liver (50%)
What is the principle stimulant of insulin secretion?
Glucose
What is the basal secretion of insulin?
~40 microgram/h under fasting conditions, there are increases of secretion linked to meals
What mediates the entry of glucose into beta cells?
GLUT2 (type 2 glucose transporters)
How does the beta cell depolarise?
- Glucose trapped within cell & is metabolised to create ATP
- Increased ATP:ADP ratio causes ATP-gated K+ channels in the cellular membrane to close up, preventing K+ from being shunted across the cell membrane
- Rise in + charge inside cell leads to depolarisation
What is the net effect of beta cell depolarisation?
Activation of voltage-gated calcium channels, which transport calcium ions into the cell
What does the brisk increase in beta cell intracellular calcium conc trigger?
- Export of the insulin-storing granules by exocytosis
- Ultimate result is the export of insulin from beta cells & its diffusion into nearby blood vessels
Insulin release is a ______ process?
Biphasic
What 2 things occur in the beta cells after the 1st fast response phase of insulin secretion?
- 2nd phase of insulin release (slower)
2. Beta cells regenerate the stores of insulin initially depleted in the 1st fast response phase
Describe the incremental (above basal) plasma insulin concentration profiles in response to a physiological entry of glucose via a meal?
- NOT a biphasic pattern
- Insulin response observed after food cannot be accounted for solely by associated changes in blood glucose level, it depends on other factors ie. free fatty acids & other secretagogues in the meal, the neurally activated cephalic phase, & GI hormones
What is the treatment for type 1 diabetes mellitus?
Insulin via subcutaneous injections (its a peptide so cannot be given orally)
Give 5 examples of insulin?
- Rapid acting- Aspart, Lispro, Glulisine
- NPH
- Detemir
- Glargine (Lantus/Toujeo)
- Tresiba (Degludec)
What are the 3 doses of insulin?
- Once-daily basal insulin
- Twice-Daily mix-insulin
- Basal-bolus therapy
Describe Levemir insulin?
- Shortest (~16hrs)
- BD>OD in T1DM
What is the duration of Lantus insulin?
~20hrs OD
What is the duration of Toujeo insulin?
~24hrs OD
What is the duration of Degludec insulin?
=> 24hrs OD
Describe Insulin glargine (Lantus®)?
- Clear, colourless solution for administration in a single daily dose
- Delivered using the OptiPen® Pro or OptiSet® pen delivery devices
- Can be used as a basal insulin in combination with oral antidiabetic agents or prandial insulin
- Not suitable for mixing with other insulins prior to injection
Describe OptiPen® Pro & OptiSet® pen delivery devices?
- OptiPen® Pro is a reusable insulin cartridge pen
- OptiSet® is a prefilled pen with a facility to preset the dosage
What are the 2 analogues for short/rapid (bolus) human Actrapid & Humulin S?
Novorapid/Fiasp Humalog, Apidra
What are the 3 analogues for intermediate/long (basal) human Insulatard & Humulin I?
- Levemir (Detemir)
2. Lantus/Toujeo (Glargine) 3. Tresiba (Degludec)
What are the 2 analogues for mixed human Humulin M3?
- Novomix 30
2. Humalog Mix 25/50
What are the 5 PROS of insulin pens?
- Convenient & easier transport than vial & syringe
- More accurate dosages
- Easier to use for impairments in visual & fine motor skills
- Less pain (as polished & coated needles are not dulled by insertion into a vial of insulin before a second insertion into the skin)
- Can be used without being noticed
Describe the purpose of Continuous Subcutaneous Insulin infusion (CSII)/ “pump therapy”?
- Have the potential to make it easier to achieve glucose control with less danger of severe & incapacitating hypoglycaemia
- However, the efficacy of this compared to SMBG is still debatable
List the 4 infrequent complications of Continuous Subcutaneous Insulin infusion (CSII)/ “pump therapy”?
- Reactions
- Infections at the cannula site
- Tube blockage
- Pump malfunction
What is the main CON of Continuous Subcutaneous Insulin infusion (CSII)/ “pump therapy”?
Expensive- costs for batteries, reservoirs, infusion sets, insulin, lancets, test strips & glucometers
What are the 2 curative treatments for type 1 diabetes mellitus?
- Islet cell transplant
2. Pancreatic transplant
What type of molecule is insulin?
Peptide
What is Whipples Triad in Hypoglycaemia?
- Symptom of low blood glucose: autonomic or neuroglycopaenic
- Measured plasma glucose: < 2.8mmol= normal. <4.0mmol= insulin-treated DM
- Better after glucose
Describe the physiology & signs of 4.6mmol/L blood glucose?
- Inhibition of insulin release
- Signs: general malaise, headache, nausea
Describe the physiology & signs of 3.8mmol/L blood glucose?
- Release of counter regulatory hormones glucagon & adrenaline
- Signs: autonomic symptoms, sweating, palpitations, shaking, nausea, anxiety, hunger
What do 70-80% of people with a blood glucose level of 3.8mmol/L have?
No symptoms
Describe the physiology & signs of 2.5-2.8mmol/L blood glucose?
- Impairment of cognitive function & concentration, inability to perform complex tasks
- Signs: confusion, drowsiness, odd behaviour, speech difficulty, incoordination, weakness, visual change, dizziness, tiredness
Describe the physiology & sign of <2mmol/L blood glucose?
- EEG changes
- Sign: seizures
What are the 2 signs of <1.5mmol/L blood glucose?
- Coma
2. Convulsions
Describe the severity scale of hypoglycaemia?
- MILD: autonomic
- MODERATE: autonomic & neuroglycopaenic
- SEVERE: autonomic & neuroglycopaenic
List 4 things hypoglycaemic patients need to do when/before driving?
- CBG> 5mmol/l before driving, carry CHO, identifiers
- If between 4-5 mmol/l then eat before driving 2 hours at a time
- Do not drive if feeling hypo or CBG <4 mmol/l
- If hypo: 1 hour before driving (from onset) & CBG>5
What are the DVLA hypo guidances for driving with group 1 entitlement hypoglycaemic patients on insulin?
- Adequate hypo awareness
- Notify if >1 severe hypo whilst awake in 12 months or most recent <3months when filling form
- Home capillary blood glucose (CBG) monitoring evidence
- Not a danger to the public
- Acuity & visual fields OK
What do Group 1 entitlement patients on tablets with a risk of hypos e.g. sulphonylureas have to bring when driving, according to the DVLA?
Home capillary blood glucose (CBG) diary
What are the DVLA hypo guidances for driving with group 2 entitlement with insulin resistant diabetes mellitus (IRDM)?
- Full hypo awareness & understanding of risks
- No severe hypos in 12 months
- Home capillary blood glucose (CBG) monitoring evidence: 3 months of recordings
- Not a danger to the public
- Acuity & visual fields OK
What are the DVLA hypo guidances for driving with group 2 entitlement with tablets risk of hypoglycaemia?
- No severe hypos in 12 months
- Full hypo awareness & understanding of risks
- CBG checks at least twice daily & more often for driving
What type of diabetes is more prone to diabetic ketoacidosis?
Mainly T1DM but now recognise ketosis prone T2DM
Describe the mortality of diabetic ketoacidosis?
- Mortality in young: cerebral oedema 70-80% deaths
- Mortality in adults: severe hypokalaemia, ARDS, illness causing decompensation
What are the 3 factors to diabetic ketoacidosis?
- Metabolic acidosis: venous bicarbonate < 18mmol. H+ > 45 mEq/L. pH < 7.3
- Plasma glucose: >13.9mmol/l
- Urinary / plasma ketones: ≥2+ urinary/ >3mmol/L
Describe the pathophysiology of diabetic ketoacidosis?
Absolute or relative insulin deficiency + Increase in stress hormones –>
- Lipolysis: FFAs: ketogenesis
- Gluconeogenesis: severe hyperglycaemia
- Osmotic diuresis + acidosis: dehydration
List the 7 clinical features of diabetic ketoacidosis?
- Osmotic Symptoms
- Weight Loss
- Breathlessness- Kussmaul respiration
- Abdominal pains, especially in children
- Leg cramps
- Nausea & vomiting
- Confusion
List the 4 main precipitating factors of diabetic ketoacidosis?
- Insulin omission- 33%
- Infections- 20-38%
- New-onset DM- 5-39%
- Acute Illness (MI, trauma, pancreatitis)- 10-20%
List the 5 other precipitants of ketoacidosis?
- Steroids
- CSII Pump failure
- Substance abuse
- Deliberate omission of Insulin dose
- Eating disorder
What are 5 reasons why someone might deliberately stop taking their insulin?
- Weight management
- Avoidance of hypoglycaemia
- Escaping domestic situation
- Depression
- Attention seeking
List the 4 typical key losses in DKA & how much is lost?
- 6-8 litres of water (100ml/kg)
- Sodium 500-1000mmol
- Chloride 350mmol
- Potassium 300-1000 (3-5 mmol/Kg)
What are the 3 treatments for DKA?
- Fluid- restoration of circulatory volume ie. crystalloid. Clearance of ketones ie. 10% dextrose
- Potassium
- Insulin
How long is the DKA care pathway?
0-4hrs (4hrs until discharge)
Describe a Hyperglycaemic Hyperosmolar State (HHS)?
- Hypovolaemia
- Very high blood glucose > 30mmol/L
- Serum osmolality >320mOsmol/l
- Bicarbonate usually > 15mmol/l
- Absence of significant ketones
What is osmolality equal to?
2 x (Na + K) + Urea + Glu
What is not present in Hyperglycaemic Hyperosmolar State (HHS)?
Ketoacidosis
What may proceed Hyperglycaemic Hyperosmolar State (HHS) proceed to?
Coma (watch GCS)
Describe the prevalence of Hyperglycaemic Hyperosmolar State (HHS)?
- Less than 1% diabetes related admissions annually
- Elderly (55-70yrs), first presentation T2DM in 30%
What are the 3 precipitating factors for Hyperglycaemic Hyperosmolar State (HHS)?
- Infection- 60%
- Poor compliance- 30%
- Drugs
What are the 3 treatment for Hyperglycaemic Hyperosmolar State (HHS)?
- Fluid- 0.9% sodium chloride
- Insulin- low dose 0.05units/kg/hr
- Other- LMWH, Foot protection
Describe the fluid treatment for Hyperglycaemic Hyperosmolar State (HHS)?
- Aim for a positive fluid balance of 3-6L by 12 hours
- Only switch to 0.45% sodium chloride if osmolality not falling despite positive fluid balance
- Rate of fall in sodium should not exceed 10mmol in 24 hours
Describe the insulin treatment for Hyperglycaemic Hyperosmolar State (HHS)?
- Rate of fall no more than 5mmol/L/hr
- Only start when glucose not falling with fluid alone
What are the 2 microvascular complications of diabetes?
- Retinopathy- leading cause of blindness in the working population in developed world. 1st microvascular complication for patients with diabetes
- Nephropathy- 30-40% of patients with diabetes,
23% of patients starting dialysis have diabetes as the primary case, but poorer survival on it
Describe the foot complications of diabetes?
Neuropathy/foot disease-
Life-time risk for a foot ulcer is 25%. 80% of non-traumatic amputations occur in patients with diabetes
What are the 5 signs & symptoms of cardiovascular complications in type 2 diabetes?
- Previous history of stroke- 7%
- Abnormal ECG- 18%
- Hypertension- 35%
- Intermittent claudication- 4.5%
- Absent foot pulses- 13%
What is the most costly complication of diabetes in relation to in-patient care?
Peripheral vascular disease (diabetic are 15x more likely to undergo amputation)
What is the 2nd major cause of death in type 2 diabetes?
Stroke (accounting for 15% of all deaths in T2DM)
What is the management for retinopathy in diabetes?
Annual photographic retinal screening with triggers for ophthalmology referral
What is the management for nephropathy in diabetes?
Annual monitoring of renal function & urinary albumin excretion, referral to renal team if nephropathy progesses e.g. CKD4; macroalbuminuria
What is the management for neuropathy/foot disease in diabetes?
Annual foot-screening (minimum) with risk stratification & referral to podiatry/vascular as appropriate e.g. progressive neuropathy, structural change, ischaemia
What is the management for cardiovascular disease (CVD) in diabetes?
- Keep BP <130/80, lower if nephropathy
- Statin therapy if T2DM and age >40 regardless of DM duration & baseline cholesterol
- Consider in T1DM especially if complications
What are 7 factors of the history which will help you decide what to do for T2DM?
- Symptoms
- When was diabetes diagnosed?
- Co-morbidities
- Drug history
- Family history
- Smoking
- Alcohol
What are 2 factors in examination which will help you decide what to do for T2DM?
- BMI
2. BP
What are 3 investigations which will help you decide what to do for T2DM?
- HbA1c
- Lipids
- Renal function
List 8 pathophysiological failures which contribute to hyperglycaemia?
- Increased glucose reabsorption
- Impaired insulin secretion
- Increased hepatic glucose production
- Increased lipolysis
- Decreased glucose uptake
- Neurotransmitter dysfunction
- Decreased incretin effect
- Increased glucagon secretion
What are 3 targets for the treatment of type 2 diabetes?
- Insulin resistance
- Decrease insulin production
- Increase blood glucose
Describe the 6 pathophysiological factors which lead to type 2 diabetes?
- Reduction in insulin release in response to glucose: reduced 1st phase response
- Failure of pulsatility of insulin secretion
- Abnormality of insulin formation
- Progressive beta cell failure
- Loss of beta cell sensitivity to glucose
- Delayed insulin secretion in response to oral glucose
List 7 drugs which are used to treat type 2 diabetes?
- DPP4 Inhibitors
- GLP-1 agonists
- Metformin
- Sulphonylureas
- Thiazolidinediones (TZDs)
- Insulin
- SGLT-2 inhibitors
How does metformin work?
Activation of adenosine monophosphate activated protein kinase (AMPK) to inhibit gluconeogenesis
What 3 effects does Metformin have on the liver?
- Reduced fatty acid & cholesterol synthesis
- Increased lipid oxidation
- Reduced gluconeogenesis
What effect does Metformin have on the skeletal muscle?
Increased lipolysis & lipogenesis
What effect does Metformin have on adipose?
Reduced lipolysis & lipogenesis
What effect does Metformin have on vascular endothelium?
Increased nitric oxide (NO) bio-availability
What 2 effects does Metformin have on the heart?
- Increased fatty acid uptake & oxidation
2. Increased glucose uptake & glycolysis
What are the 5 overall effects of Metformin on the body?
- Weight loss
- Increased insulin sensitivity
- Improved glycaemia
- Improved lipid profile
- Improved vascular function
Describe the mechanism of action of sulphonylureas on pancreatic beta cells?
- Bind & close ATP-sensitive K+ (KATP) channels on cell membrane, which depolarises the cell by preventing K+ exiting
- Opens voltage-gated Ca2+ channels
- Rise in intracellular Ca2+ –>increased secretion of mature insulin & therefore decrease plasma glucose
What is the evidence for type 2 diabetes benefits from Pioglitazone?
Secondary prevention of macrovascular events in the PROactive study (randomised controlled trial)
List the 6 limitations of older type 2 diabetes therapies?
- Weight gain (SU, TZD, insulin)
- Hypogylcaemia (SU, insulin)
- Concerns over CV safety (TZD)
- Concerns over cancer risks (TZD, some insulins)
- Limited options in patients with renal disease
- Natural history of disease not altered
What is the incretin effect?
The difference in insulin response between orally delivered & IV delivered glucose
What happens to DPP-4 when they are inhibited?
Rapidly inactivated to GLP-1 & GIP
What is the effect of increased GLP-1 & GIP on the pancreas beta cells?
Increased insulin –> Increased glucose uptake in fat & muscle
What is the effect of increased GLP-1 & GIP on the pancreas alpha cells?
Decreased glucagon –> Decreased glucose production in the liver
What effect does Increased GLP-1 have on the hypothalamus?
Decreased appetite
What effect does Increased GLP-1 have on the stomach?
Decreased gastric emptying
What are incretins?
- Group of metabolic hormones (GLP-1 & GIP) that stimulate a decrease in blood glucose levels
- They are released after eating & augment the secretion of insulin released from pancreatic beta cells of the islets of Langerhans
List the 4 PROS/CONS of incretin based therapy?
- Weight loss
- Risk of hypoglycaemia
- Likely benefit?
- Special groups- elderly & renal impairment as it is renally excreted
Give an example of a SGLT-2 inhibitor drug?
Empagliflozin
What are the advantages of SGLT-2 inhibitor drugs for treating type 2 diabetes?
Reduces hyperglycaemia, BP & CV risk
Describe SGLT-2 inhibitor drugs for treating type 2 diabetes?
- Inhibit SGLT2 in thePCT& so increase glucose excretion in the urine
- Used when HbA1c>53mmol/mol
Describe the treatment pathway for type 2 diabetes?
Lifestyle changes (diet & exercise) –> Oral diabetes therapy –> GLP-1s –> Insulin
What should all development programmes for T2D rule out?
Unacceptable increase in CV risk
Give 4 examples of DPP4 inhibitor drugs used to treat type 2 diabetes?
- Sitagliptin
- Alogliptin
- Vildagliptin
- Omarigliptin
Give 6 examples of GLP1 agonist drugs used to treat type 2 diabetes?
- Semaglutide
- Lixisenatide
- Liraglutide
- Exenatide
- Dulaglutide
- Albiglutide
Give 4 examples of SGLT2 inhibitor drugs used to treat type 2 diabetes?
- Empagliflozin
- Canagliflozin
- Ertugliflozin
- Dapagliflozin
Describe the mechanism of action of DPP4 inhibitors?
- Inhibit DPP4 which normally breaks down incretins
- Results in increased insulin
When would you use DPP4 inhibitors?
Should be considered, usually as dual or triple therapy, for lowering HbA1c
Describe the 3 cases in which GLP-1 agonists would be used?
- Considered when BMI => 30kg/m2 in combo with oral glucose-lowering drugs or basal insulin as 3rd/4th line treatment, when adequate control has not been achieved
- Considered as an alternative to insulin in people who combo of oral agents have been inadequate & insulin would otherwise be the next option
- Type 2 diabetes & established CV disease, Liraglutide should be considered
Describe the mechanism of action of SGLT2 inhibitors?
- Work at proximal tubule in kidneys
- Act to reduce glucose reabsorption & increase glucose excretion
When would you use SGLT2 inhibitors?
- Considered as add-on therapy to Metformin in people with T2DM
- T2DM & established CV disease, Empagliflozin & Canagliflozin should be considered
What is the 1st line (in addition to lifestyle measurements) drugs for T2DM?
- Metformin OR
2. Sulphonylurea if osmotic symptoms or intolerant to metformin
What is the 2nd line (in addition to lifestyle measurements) drugs for T2DM?
- Sulphonylurea OR
- SGLT2 inhibitor OR
- DPP-4 inhibitor OR
- Pioglitazone (thiazolidinedione)
What is the set glycaemic target for T2DM?
HbA1c <7% (53mmol/mol)
What is the 3rd line (in addition to lifestyle measurements) drugs for T2DM?
- Sulphonylurea OR
- SGLT2 inhibitor OR
- DPP-4 inhibitor OR
- Pioglitazone (thiazolidinedione) OR
- Injectable GLP-1 agonist OR
- Injectable basal insulin
When would you need to get a specialist to treat T2DM (4th line)?
If not reaching target after 3-6months, review adherence
What would you do to the other drugs when prescribing a 3rd line injectable GLP-1 agonist for T2DM?
- Stop DPP-4 inhibitor
- Consider reducing sulphonylurea
- Continue metformin
- Can continue Pioglitazone
- Can continue SGLT2 inhibitor
What would you do to the other drugs when prescribing 3rd line injectable basal insulin for T2DM?
- Can continue metformin, Pioglitazone, DPP-4 inhibitor or SGLT-2 inhibitor
- Can reduce/stop sulphonylurea
Describe the type of basal insulin given as a 3rd line treatment for T2DM?
- Inject before bed
- Use NPH (isophane) insulin or longer-acting analogues according to risk of hypoglycaemia
What 4 T2DM drugs have a CV benefit?
- Metformin
- SGLT-2 inhibitors
- Pioglitazone
- GLP-1 agonist
What 2 T2DM drugs have a high hypoglycaemic risk?
- Sulphonylurea
2. Basal insulin
What 3 T2DM drugs can cause weight gain?
- Sulphonylurea
- Basal insulin
- Pioglitazone
What T2DM drugs have the lowest chance of side effects?
DPP-4 inhibitors
What 2 T2DM drugs have GI side effects?
- Metformin
2. GLP-1 agonists
What main adverse effect does SGLT2- inhibitors have?
Genital mycotic
What main adverse effect does Pioglitazone have?
Oedema/fractures
What should you do if a T2DM patient need insulin intensification?
Add prandial insulin or switch to twice daily mixed biphasic insulin
Describe the 2 concluding factors of past evidence/cases to efficient & sensible diabetic control?
- All patients should have an individualised approach including defining treatment specific targets & whether these are aimed at symptomatic or prognostic benefit
- All treatment choices should be reviewed regularly balancing benefit & risks of therapeutic intervention
What 5 hormones does the anterior pituitary release?
- ACTH
- GH
- TSH
- Gonadotropins (FSH, LH)
- Prolactin
What 2 hormones does the posterior pituitary release?
- ADH
2. Oxytocin
What 5 hormones does the hypothalamus release?
- Growth hormone releasing hormone (GHRH)
- Gonadotrophin releasing hormone (GnRH)
- Corticotrophic releasing hormone (CRH)
- Thyroid releasing hormone (TRH)
- Dopamine
List the 5 cell types in the anterior pituitary?
- Somatotrophs (50%)
- Gonadotrophs (10%)
- Corticotrophs (10-15%)
- Thyrotrophs (5%)
- Lactotrophes (20%)
Describe the ADH regulation of water balance?
Osmoreceptors in the hypothalamus –> Increase ADH release from the posterior pituitary –> Decrease free water excretion in the kidneys
What are 4 other names for ADH?
- AVP
- Vasopressin
- Arginine vasopressin
- Argipressin
What are the 6 rules of endocrinology?
- Most hormones levels fluctuate- random level ie. cortisol
- Too much of a hormone?- suppress it
- Not enough of a hormone?- stimulate it
- Do biochemical tests first & imaging later
- Primary= problem with gland itself
- Secondary= problem elsewhere
What is fT4?
Thyroxine
What would you give 1st before starting a patient on thyroxine & testosterone?
Hydrocortisone
What type of surgery do we do for a pituitary adenoma?
Transphenoidal surgery
Describe hypopituitarism?
- Failure of (anterior) pituitary function
- Can affect single hormonal axis or all hormones (panhypopituitarism)
What does hypopituitarism lead to?
Secondary gonadal/thyroid/adrenal failure
What is the treatment for hypopituitarism?
Need multiple hormone replacement
List the 6 causes of hypopituitarism?
- Tumours
- Radiotherapy
- Infarction / haemorrhage (apoplexy)
- Infiltration (eg sarcoid)
- Trauma
- Lymphocytic hypophysitis (autoimmune)
What 2 things are associated with Infarction / haemorrhage (apoplexy) causing hypopituitarism?
- Associated headache / visual disturbance
2. Associated postpartum pituitary gland necrosis (Sheehan’s syndrome)
What would you give as replacement for ACTH deficiency?
Hydrocortisone
What would you give as replacement for TSH deficiency?
Thyroxine
What would you give as replacement for FSH/LH deficiency?
- Testosterone (males)
- Oestrogen (females)
What would you give as replacement for GH deficiency?
Growth hormone (children)
What would you give as replacement for PRL (prolactin) deficiency?
No replacement
What are 4 causes of high prolactin?
- Prolactinomas (tumours of pituitary gland)
- Physiological- lactation/pregnancy
- Drugs (that block dopamine)- Tricyclics/ antiemetics/antipsychotics
- “Stalk” effect- due to loss of inhibitory dopamine from hypothalamus
What are the 4 key questions to ask for pituitary tumours?
- How big is it?
< 1cm micro (adenoma)
> 1cm macro (adenoma) - Is it releasing any hormones?
- Is it stopping the rest of the pituitary from working normally?
- Is it compressing surrounding tissues? eg optic chiasm
What are the 3 types of pituitary tumours?
- Non-functioning (majority) so they just grow
- Functioning
- Others- Craniopharyngioma, pituitary cancer, Rathke’s cyst
List 4 functioning pituitary tumours?
- Prolactin (prolactinoma)
- GH (acromegaly)
- ACTH (Cushing’s disease)
- TSH (TSHoma)
Describe non-functioning pituitary tumours?
- Commonest (25 % of all pituitary tumours)
- No hormonal release
List 4 problems that non-functioning pituitary tumours cause?
- Visual field defects
- Headache
- Stops other pituitary hormones working
- Eye movement problems (cranial nerve disturbance)
What 4 investigations would you do for non-functioning pituitary tumours?
- Imaging (MRI)
- Visual field assessment
- Prolactin
- Other pituitary hormones
What are the 3 treatments for non-functioning pituitary tumours?
- Surgery (help protect vision)
- RT if its aggressive
- Medical management unhelpful
What is a prolactinoma?
Pituitary tumours releasing prolactin (2nd most common type of pituitary tumour)
Describe the 2 sizes of prolactinomas?
- Micro < 1 cm
2. Macro > 1 cm
List the 5 clinical features of prolactinomas?
- Galactorrhoea
- Headaches
- Mass effect
- Visual field defect
- Amenorrhoea / erectile dysfunction
Describe the 3 ways to diagnose a prolactinoma?
- Serum prolactin usually > 6000
- MRI pituitary
- Test remaining pituitary function- gonadal function & thyroid hormones most affected
Describe the medical treatment of prolactinomas?
Dopamine agonists help to bring down prolactin & shrink the tumour
Give 3 examples of Dopamine agonists used in the treatment of prolactinomas?
- Cabergoline
- Bromocriptine
- Quinagolide (these drugs are also used in Parkinson’s disease)
What are 2 scenarios for surgical treatment of prolactinomas?
- Visual field compromise
2. Failure of medical therapy