Diabetes Flashcards
Define gestational diabetes mellitus (GDM)
Carbohydrate intolerance of variable severity with onset or first recognition during the present pregnancy.
What are the plasma glucose cut offs for diagnosing GDM?
Fasting: >5.1 mmol/L
OGTT 1 hr post: >=10.0 mmol/L
OGTT 2 hr post: >8.5 mmol/L
What are the plasma glucose cut offs for diagnosing DM in pregnancy?
Fasting: >= 7.0 mmol/L
*No OGTT 1 hr post criteria.
OGTT 2 hr post: >=11.1 mmol/L
Random: >=11.1 mmol/L
What are the plasma glucose cut offs for diagnosing impaired glucose tolerance?
Fasting: >=6.1 but <7.0 mmol/L
*No OGTT 1 hr post criteria.
OGTT 2 hr post: >=7.8 but <11.1 mmol/L
What congenital malformations are associated with pre-existing DM?
Congenital heart disease
Anencephaly
Microcephaly
Neural tube defects
Sacral agenesis - specific to diabetes, but rare
Directly proprotional to HbA1c during first 10/40
In the first trimester, what maternal risks are present with pre-existing DM?
- Hypogclyaemia (with nausea and vomiting / hyperemesis in pregnancy)
- Impaired hypoglycaemia awareness during pregnancy
- Diabetic ketoacidosis
For women with pre-existing DM, how often should the HbA1c be tested?
At least once a trimester
What are the treatment goals for women with pre-existing DM?
Fasting: 4.0 - 5.3
1 hour: 5.5 - 7.8
2 hours: 5.0 - 6.7
How do insulin requirements change during pregnancy?
Insulin requirements increase steadily through pregnancy - T1DM may need a 2 fold increase in pre-pregnancy insulin; T2DM may require insulin in addition to metformin.
Decline slightly towards term
Small reductions 5-10% are common
HOWEVER, marked decreases > 15% raise concern regarding placental function
- limited evidence
- indication for surveillance rather than delivery
If EFW > 4.5kg with DM, there is a _____ risk of shoulder dystocia
20%
Therefore, consideration should be given to El LSCS
But NNT to prevent one permanent BPI is 443
How are monogenic diabetes disorders inherited?
Autosomal Dominant
Fetus has 50% chance of inheriting it
What are risk factors for developing GDM?
BMI > 30
AMA 40+
Previous GDM
Family history of diabetes (first degree relative with DM or sister with GDM)
Ethnicity: Asian, Indian subcontinent, Aboriginal and Torres Strait Islander, Maori, Pacific Islander, Middle Eastern, non-white African
Previous baby > 4.5kg
PCOS
Medications: corticosteroids, antipsychotics
When should women have diabetes testing in pregnancy, and how?
All women:
- Booking HbA1c
- 75g OGTT at 26-28/40
Women with risk factors:
- early pregnancy OGTT
- repeat OGTT at 24-28 weeks if not diagnosed in early pregnancy
2 step procedure with polycose no longer recommended.
What is the recommended timing of delivery for a woman with T1DM or T2DM
At the latest, 38+6/40
Because after 39/40, risk stillbirth goes up (RR with DM is 7.2)
What are the signs and symptoms of DKA?
Nausea, vomiting Abdominal pain Thirst, dry mouth Reduced urine output Unusual, fruity smelling breath Rapid breathing, dyspnoea Tachycardia, palpitations Drowsiness, confusion, disorientation
What is the Pederson hypothesis?
Maternal hyperglycaemia leads to fetal hyperglycaemia which causes fetal pancreatic ß cells hyperplasia, and increased circulating insulin.
Insulin is an anabolic growth promoting hormone, which causes increased neonatal fat deposition and abdominal girth with increased birth weight.
Briefly describe the MIG Trial
Aim: To rule out a 33% increase in a composite of perinatal complications in infants of women treated with Metformin as opposed to Insulin
Randomised: to Metformin up to 2500mg / day (+Insulin if required to achieve glycaemic control), or Insulin
Primary outcome: Composite measure of neonatal outcome including neonatal hypoglycaemia, RDS, PTB, low APGARS etc
Results: No difference in the primary outcome between both groups
I.e Metformin safe in pregnancy
Less SEVERE neonatal hypoglycaemia in the Metformin Group
Of women in the Metformin group, 46% needed Insulin as well
Women referred metformin treatment to taking insulin
What was the only intervention that was found to PREVENT women from developing GDM
Cochrane 2020
Diet and exercise (combined)
What are the OGTT values used to diagnose GDM?
fasting >/= 5.1
1 hour >/= 10
2 hour >/= 8.5
What HbA1c levels indicate insulin resistance and diabetes mellitus?
IR = 42-47 DM = >/=48
Who requires GDM screening at earliest opportunity after pregnancy confirmed? And how is this screening conducted?
2 moderate OR 1 major risk factor:
High risk factors for GDM
• Previous GDM
• Previously elevated blood glucose level
• Maternal age ≥40 years
• Family history DM (1st degree relative with diabetes or a sister with GDM)
• BMI > 35 kg/m2
• Previous macrosomia (baby with birth weight > 4500 g or > 90th centile)
• Polycystic ovarian syndrome
• Medications: corticosteroids, antipsychotics
Moderate risk factors for GDM
• Ethnicity: Asian, Indian subcontinent, Aboriginal, Torres Strait Islander, Pacific Islander, Maori, Middle Eastern, non‐white African
• BMI 25 – 35 kg/m2
Screening:
HbA1c AND 75g 2h OGTT at earliest opportunity after pregnancy confirmed. Repeat OGTT at 24-28 weeks if not diagnostic in early pregnancy.
What is the risk of PET in GDM, T1DM, T2DM and DM with nephropathy?
GDM - 10%
T1DM, T2DM - 15-20%
DM with nephropathy - up to 50%
What should occur at the initial visit for women with pre-existing DM?
Booking bloods
HbA1c
Creatinine
ACR
retinopathy screening (if not within last 3 months)
Ensure taking higher dose 5mg folic acid and iodine
Check height, weight, BMI and BP
Screen for CVD risk factors
Review medications - change to metformin +/- insulin
Counselling around risks of adverse obstetric outcomes, and potential disease progression in pregnancy
Also: TFTs and consider coeliac serology screening in T1DM
When should delivery be planned for T1DM/T2DM and GDM?
T1DM/T2DM = 37-38+6 (risk stillbirth increases dramatically from 39wk) GDM = Delivery by 40+6; earlier dependant on risk factors
