Diabetes Flashcards
Definition of diabetes
A metabolic disorder characterized by resistance to the action of insulin, insufficient insulin secretion or both
What is the main clinical manifestation of diabetes
hyperglycemia
Types of DM
Type I, Type II, Gestation, Others (Infections, drugs, monogenic diabetes syndrome, endocrinopathies, pancreatic destruction, type III)
What is Type I DM pathogenesis?
An absolute deficiency of pancreatic B-cell function:
- Immune mediated destruction
- Positive antibodies (doesnt mean +ve means have symptoms straight away).
What is Type II DM pathogenesis?
- Progressive loss of adequate β-cell insulin secretion on the background of insulin resistance
- Insulin resistance:
In the presence of insulin, glucose utilization is impaired and hepatic glucose output increased.
Simultaeneous elevations in both glucose and blood insulin levels at early stage.
Difference between Type I and II
Primary Cause:
Type I- autoimmune mediated pancreatic beta cell destruction, positive antibodies
Type II- insulin resistance, impaired insulin secretion, negative antibodies
Insulin production (C-peptide level):
Type I- absent
Type II- normal or abnormal
Age of onset:
Type I- <30y/o
Type II- >40y/o
Onset of clinical presentation:
Type I- abrupt
Type II- gradual
Physical appearance:
Type I- often thin
Type II- often overweight
Proneness to ketosis:
Type I- freq
Type II- uncommon
What does the presence of C-peptide mean?
It is a short chain a.a released as by product of formation of insulin by pancreas. If insulin is present, C-peptide will be released.
S&S of hyperglycemia
Extreme thirst (polydipsia)
Freq urination (polyuria)
Dry skin
Hunger (polyphagia)
Blurred vision
Drowsiness
Decreased healing
3Ps
S&S of hypoglycemia
Shaking
Fast heartbeat
Sweating
Dizziness
Anxious
Hunger
Impaired vision
Weakness/fatigue
Headache
Irritable
Common S&S of hyper and hypoglycemia
Hunger and impaired vision
What types of tests are used to measure DM
Fasting/Basal plasma glucose (FBG)
Random or casual plasma glucose
Postprandial plasma glucose (PPG)
Hemolobin A1c (HbA1c)
What to take note of for FBG test?
No calories intake for >=8hrs
When is random or casual plasma glucose taken?
glucose level is taken at any time of the day, regardless of meals
When and how is PPG taken?
- Glucose level measured after meal; usually after 2 hours (Also known as 2-hour postprandial glucose -> tend to be more stable)
- Can also be measured using a standardized 75-g oral glucose tolerance test (OGTT)
What does HbA1c measures?
- Measures the average amount of glucose (attached to hemoglobin) in a person’s blood over the past 3 months. (3months avg of FPG + PPG)
- Glucose stays attached to hemoglobin for the lifespan of a red blood cell (~120 days)
Notes: Depends on no. of RBC in body -> if bleeding/mensus, HbA1c is lower. If anemia, RBC dont turn over, they last for >120days so HbA1c increases.
How does basal and postprandial changes as HbA1c increases?
As HbA1c increases, basal increases and postprandial decreases.
Note: we give insulin at high HbA1c as certain insulin targets the basal/fasting hyperglycemia
How often should T1DM use glucometers?
- Varies but generally:
- > =4times/day
- before meals/snacks, at bedtime, at 3am
How often should T2DM use glucometers?
- Varies but generally:
- > =3times/day for pts on multiple injections of insulin
- For patients using less frequent insulin injections, noninsulin therapies, or medical nutrition therapy alone, self monitoring of blood glucose (SMBG) may be useful as a guide to the success of therapy
Criteria for diagnosis of T2DM:
What does HbA1c <=6.0% suggest?
- Low probability of diabetes
- No further tests needed if no smx of diabetes. Further testing with a FPG or a 2hOGTT is rec if diabetes is suspected
- Diagnosis: no diabetes, maintain healthy lifestyle and weight. Repeat test in 3yrs
Criteria for diagnosis of T2DM:
What does HbA1c 6.1- 6.9% suggest?
- proceed to FPG or OGTT
- if FPG <=6.0mmol/L or 2hOGTT <7.8mmol/L: no diabetes. diagnosis same as HbA1c <=6.0%
- If FPG 6.1-6.9mmol/L or 2hOGTT 7.8-11mmol/L: pre-diabetes
- if FPG >=7.0mmol/L or 2hOGTT >=11.1mmol/L: diabetes
Criteria for diagnosis of T2DM:
What does HbA1c >=7.0% suggest?
- high probability of diabetes
- no further tests needed
- diagnosed as diabetes straight away
Can FBG or OGTT be used for diagnosis if HbA1c was not done?
Yes, but both FPG and OGTT must be done and both give abnormal results
How does culture/race influence diabetes risk?
- Genetics/fam Hx: asians higher risk, have less muscle and more abdominal fat which increases insulin resistance
- Environment: stress, fast food, less exercise, poor health literacy, language barrier
- Food: asian diet is carb heavy and tend to stir/deep fry with oil
What are the risks of ramadan fasting and effects on DM management?
- No food: hypoglycemia, lack of exercise, binge eating for iftar
- No water: risk of dehydration and thrombosis, risk of acute diabetes (DKA/HHS)
- No medications: risk of hyperglycemia, risk of acute diabetes (DKA/HHS)
What are the general DM medication adjustments during ramadan?
- TDS to BD
- Reduce Medications With high hypoglycemia potential eg. insulin, SU
- Evening dose potency to be higher than morning (as sunset meal is much heavier than predawn meal)
- Be Aware That Overall, patients eat lesser during Ramadan period -> adjust accordingly
Risk factors for diabetic foot infections?
Poor glycemic control
Peripheral Artery DIsease: low supple of blood to area
Peripheral neuropathy
Visual impairment
Smoking: damages vascular tissue cause clots and reduces artery thickness -> PAD
What should you educate pt abt diabetic foot care?
- Maximising blood glucose control/ reduce risk factors
- Self-examination of the foot (every night, look out for any cracks, dryness, wounds. Use mirror to see bottom of feet)
- Foot protection (cover feet with socks at all times, dont be bare footed. Nice fitting shoes + socks can be too tight, prevent blood circulation. Too loose also cause alot of abrasions -> wounds)
- Nail & Foot Care & Hygiene
Use moisturisers but dont moisturise btw toes -> fungal infection
Prevent ingrown nails, dont cut too thinly, leave abit of gap, cut straight across nail and leave adges sharp to less likely for ingrown nails
Wash feet everyday w soap. Soak in warm water 1-2minutes/day. Too long: skin gets weak. - Annual Foot examination (nurse/pharmacists feel pulses of foot to check for PAD or neuropathy- using filament. How strong pulse is can tell how severe PAD is).
Vascular assessment of pedal pulses
Neurologic exam with monofilament
Complications of DM?
- Retinopathy (microvascular)
- Nephropathy (microvascular)
- Neuropathy (microvascular)
- Decrease life expectancy
- Increase CVD (macrovascular)
R/S btw macrovascular outcome and A1c?
CV outcomes improve as A1c decreases but eventually worsens as A1c continues to drop
General treatment goals for DM?
HbA1c: <=7%
FBG: 4-7mmol/L
PPG: <10mmol/L
When should HbA1c goal be more stringent?
❑ 6.0-6.5%
❑ Short disease duration
❑ long life expectancy (young pts)
❑ no significant cardiovascular diseases
When should HbA1c goal be less stringent?
❑ 7.5-8.0%
❑ History of severe hypoglycemia
❑ Limited life expectancy
❑ Advanced complications
❑ Extensive comorbid conditions
❑ Those in whom target is difficult to attain despite intensive SMBG, repeated counselings, and effective pharmacotherapy
Monitoring parameters in T2DM?
- HbA1c
- Lipid panel
- BP
- Eye exam
- Albuminuria/renal function
- Foot exam
What are the nonpharm TLC for diabetes?
Quit smoking
➢ 5As: Ask, Assess, Advice, Assist, Arrange
Weight Reduction
➢ Achieve and maintain 7% loss of initial body weight -> good prognosis esp for newly diagnosed pts, helps decrease insulin resistance.
Exercise
➢ 150 min/week, spread into at least 3 days per week with no more than 2 consecutive days without exercise
Moderate intensity
➢ PLUS muscle strengthening activities at least 2 days per week
➢ If older (>55yo) – PLUS incorporating balance and functional training
Diet Modification (most challenging)
➢ Fruit, vegetables, grains, cereals, legumes
➢ Skinless poultry, fish, lean meats
➢ Low-fat dairy products
➢ Restrict alcohol and simple carbohydrates (mainly ↓ TG). Cut down on carbs
Types of antidiabetic drug classes
- a glucosidase inhibitors
- incretins (GLP-1 receptor agonist)
- sulfonyurea
- metformin
- thiazolidinediones
- SGLT2i
- DPP-4i
- meglitinides
What is an off-label use for metformin?
Polycystic ovarian syndrome (PCOS)
MOA of metformin
- Primary: ↓ hepatic glucose production
- Secondary: ↑ peripheral/muscle glucose uptake and utilization (i.e. ↑ insulin sensitivity)
How is metformin cleared?
renal; 90% in urine as unchanged drug -> must dose adjust.
SE of metformin
- Common: GI (diarrhoea -> so take after food), anorexia, metallic taste (usually transient; take with food to alleviate, taste like blood)
- Long-term use may ↓serum B12 concentrations (ADA 2017 update: consider periodic measurement especially in those with anemia or peripheral neuropathy) -> megaloblastic anemia (RBC bigger than normal)
- Rare but fatal: lactic acidosis (3/100,000 patients/year)
S&S of lactic acidosis
nausea, shallow/labored breathing, mental confusion
Max dose for metformin?
2.55g/day
Is metformin safe in pregnancy?
Yes
How does lactic acidosis occur?
- Glucose gets broken down into pyruvate for ATP
- Pyruvate gets broken down to lactate when there is a lack of oxygen (anaerobic respiration)
- Lactate acidosis results from ↑ production or ↓ clearance of lactate
➢Metformin
➢Hypoxic state (lack of oxygen in blood)
CI for metformin
➢ Severe renal impairment (Cleared by renal)
➢ Hypoxic states or at risk for hypoxemia: Heart failure, sepsis, liver impairment, alcoholism, ≥ 80 yo -> if pt is stable, can still give
Warning remains for patients with HF due to ↑ risk for hypoxemia and hypoperfusion; avoid use in acute HF
Drug interactions with metformin?
➢ EtOH: ↑ risk for lactic acidosis
➢ Iodinated contrast material/radiologic procedure
temporarily hold metformin x ≥48 hrs after contrast administration; restart when renal function returns to normal post-procedure
(Can cause contrast induced renal impairment -> metformin is renally cleared. )
➢ Cationic drugs (e.g. dofetilide, cimetidine, digoxin) may ↑ metformin by competing for renal tubular transport, less metformin is excreted.
How to renal adjust metformin?
eGFR:
30-44: lower dose (50% or half maximal dose)
<30: stop metformin
First line for T2DM and gestational DM
Metformin
Does metformin cause weight gain?
No
What is pre-diabetes?
Impaired Fasting Glucose (IFG): 6.1 - 6.9 mmol/L (fasting) OR Impaired Glucose Tolerance (IGT): 7.8 - 11.0 mmol/L (after 2h 75g OGTT).
No A1c as HbA1c is a range -> not accurate to determine if you are pre-diabetic esp in Asians.
How to prevent or delay Type 2 DM
- Diabetes prevention programme shows that lifestyle changes is still btr than drugs.
- Lifestyle interventions:
➢ Achieve and maintain 7% loss of initial body weight
➢ Increase moderate-intensity physical activity to at least 150mins/week - Metformin therapy
➢ Especially for those with BMI >35 kg/m2, those aged <60 years, and women with prior gestational diabetes mellitus
When is Sulfonylureas indicated? (SU)
Management of T2DM when hyperglycemia cannot be managed by diet and exercise alone; may be use concomitantly with other antidiabetic agents and/or insulin
But need functional beta cells to work
Examples of different generations of SU
- First generation SU (rarely used due to ↑ likelihood for adverse effects except tolbutamide):
Tolbutamide - Second Generation SU:
Glipizide (blue tablet), Gliclazide, Glibenclamide (also known as Glyburide in the US) - Third generation SU:
Glimepiride
MOA of SU
- Primary: stimulate insulin secretion by blocking K+ channel of the ß- cells
- Secondary: ↓ hepatic glucose output and ↑ insulin sensitivity
Notes: Need functional Beta cells to work! Hence, SU is only used in T2DM as T1DM does not have functional B cells. As T2DM progresses, B cells become less and less effective in secreting insulin so SU loses effectiveness over time.
How is glipizide cleared?
hepatic. so good for those with renal impairment
When should SU be taken?
15-30min before meals
Note: SU stimulates secretion of insulin which is what you want after eating so must be take 15-30mins before meals. If you skip a meal, dont take SU -> hypoglycemia as SU works on postprandial.
SE of SU
- Hypoglycemia (especially in elderly)
- Weight gain (~2-5 kg) -> as long as stimulate insulin, there will be weight gain
- Blood dyscrasias (rare)
DDI for SU
- ß-blockers may mask s/sx of hypoglycemia -> BB are used to treat tremors and tachy which is the same symptoms as hypoglycemia. Only sweating cannot be masked.
- Disulfiram-like rxn with EtOH (1st gen»_space; 2nd/3rd gen): tolbutamide.
- CYP2C9 inhibitors (e.g. amiodarone- anti arrhythmic, 5-FU- cancer, fluoxetine- anti depressant) may ↑ glimepiride, glipizide
What to caution in pts taking SU?
Pts with irregular meal schedules
MOA of Thiazolidinediones (TZDs)
- Peroxisome proliferator activated receptors agonist to promote glucose uptake into target cells (skeletal muscle/adipose):
↓insulin resistance; ↑ increase insulin sensitivity (effective for T2DM whr insulin is resistant so the drug kind of counteracts it) - No effects on insulin secretion
How long does it take for TZD to work?
Up to a month
How is TZD eliminated?
Liver
Which TZD is FDA approved for use in combi with insulin?
Pioglitazone: synergistic effect so very prone to hypoglycemia
BBW for TZD
Increases risk of congestive heart failure.
- Contraindicated in NYHA Class III or IV HF
- After initiation or dose increases, observe patients for signs and symptoms of HF
- If confirmed HF signs and symptoms develop, appropriate management of HF should be initiated. Discontinuation or dose reduction should be considered.
SE of TZD
- Hepatotoxicity:
Do not initiate therapy if ALT >3x UNL
Discontinue if ALT >3x UNL
If ALT > 1.5x UNL during therapy, repeat LFTs then weekly until normal
Discontinue if s/sx of hepatic dysfunction regardless of ALT level - Edema (caution in NYHA Class I or II HF)
- Fracture (increased risk; more likely in women)
- Weight gain (assoc w edema)
- Bladder cancer (Pioglitazone)
- Elevated LDL (Rosiglitazone)
CI for TZD
Active liver disease; NYHA Class III or IV HF
Long term use of TZD is associated with what?
Fractures (F > M)
Which antidiabetic appears to be beneficial for pts with fatty liver disease?
TZD
➢ Nonalcoholic fatty liver disease (NAFLD) -> usually obese pts & not due to alcohol -> usually assoc w diabetes.
➢ Nonalcoholic steatohepatitis (NASH) -> more complicated.
Off label use for a-glucosidase inhibitor
treatment in patients with T1DM who are on insulin therapy but require additional control in PPG level
Examples of TZD
Rosiglitazone, Pioglitazone