GESTATIONAL DIABETES MELLITUS Flashcards
– pregnancy-related hyoerglycemia
HUMAN PLACENTAL LACTOGEN
– similar to action of GH (inhibits insulin)
HUMAN CHORIONIC SOMAMOTROPIN
Glucose intolerance which develops in [?] of pregnancies
7%
Abnormal glucose concentration discovered for the 1st time during pregnancy
GESTATIONAL DIABETES MELLITUS
ONE-STEP STRATEGY
2011 Standards of Care – ADA
TWO-STEP STRATEGY
2013 – NIH
24 to 28 weeks of gestation
ONE-STEP STRATEGY
TWO-STEP STRATEGY
Step 1: Perform a 75-g OGTT (fasting, 1H, and 2H BGL)
ONE-STEP STRATEGY
Step 1: Perform a 50-g GLT (non-fasting)
TWO-STEP STRATEGY
1H PG measurements
TWO-STEP STRATEGY
If the 1H PG is [?], or [?], proceed to a [?]
> or = to 130 mg/dL
140 mg/dL
100-g OGTT
Step 2: The 100-g OGTT should be performed when the patient is fasting
TWO-STEP STRATEGY
ONE-STEP STRATEGY
Diagnosis of GDM is made when any or the PG values are = or > than any of the ff PG levels:
Fasting:
92 mg/dL (5.1 mmol/L)
ONE-STEP STRATEGY
Diagnosis of GDM is made when any or the PG values are = or > than any of the ff PG levels:
1 h:
180 mg/dL (10.0 mmol/L)
ONE-STEP STRATEGY
Diagnosis of GDM is made when any or the PG values are = or > than any of the ff PG levels:
2 h:
153 mg/dL (8.5 mmol/L)
TWO-STEP STRATEGY
Diagnosis of GDM is made if at least two values are = to or > than any of the ff PG levels:
Fasting:
105 mg/dL
TWO-STEP STRATEGY
Diagnosis of GDM is made if at least two values are = to or > than any of the ff PG levels:
1 h:
190 mg/dL
TWO-STEP STRATEGY
Diagnosis of GDM is made if at least two values are = to or > than any of the ff PG levels:
2 h:
165 mg/dL
TWO-STEP STRATEGY
Diagnosis of GDM is made if at least two values are = to or > than any of the ff PG levels:
3 h:
145 mg/dL
Results from an imbalance between glucose utilization and production
HYPOGLYCEMIA
Observable symptoms appear at about
50 to 55 mg/dL
ADRENALINE
EPINEPHRINE
Triggered by the ANS
NEUROGENIC/ADRENERGIC
Tremulousness, palpitations, anxiety
NEUROGENIC/ADRENERGIC
Diaphoresis (cold sweat)
NEUROGENIC/ADRENERGIC
Hunger
NEUROGENIC/ADRENERGIC
Paresthesias (numbness)
NEUROGENIC/ADRENERGIC
CNS hypoglycemia
NEUROGLYCOPENIC
Dizziness, tingling, difficulty in concentrating, blurred vision
NEUROGLYCOPENIC
Confusion, behavioral changes, seizure, coma
NEUROGLYCOPENIC
aka fast Hgb, glycosylated Hgb
Glycohemoglobin
– major fraction; predominant form
HbA1c
Non-enzymatic condensation between glucose and the N-terminal valine of each B-chain
HbA1c
Occurs over the lifespan of the RBC (90 to 120 days)
HbA1c
[?] ——– [N-terminal of B]
Glucose + Valine
[?] (unstable aldimine) ——– [Amadori rearrangement]
SCHIFF BASE
(stable)
KETOAMINE
GHb testing provides an index of ave. BGL over the
past 2-4 months
Values for [?] have a high degree of correlation
total HbA1 & HbA1c
Labile fraction (Schiff base or pre-A1c): accounts for [?] of total HbA1
5 to 8%
GHb testing Advantages:
- Provides objective means of
- Additional confirmation of the
reflecting control of DM
clinical impression of control
Cation-exchange resin or carboxymethyl cellulose resin
ION-EXCHANGE CHROMATOGRAPHY
HbA1 elutes from the column first
ION-EXCHANGE CHROMATOGRAPHY
False elevation: labile fractions, HbF
ION-EXCHANGE CHROMATOGRAPHY
Low values: Hb variants
ION-EXCHANGE CHROMATOGRAPHY
Reference method
HPLC
Separates and quantifies HbA1c and other haemoglobin types
HPLC
Hb A1c — acid — 5-HMF
COLORIMETRY
Specific for ketoaminelinked
COLORIMETRY
Unaffected by HbF, Hb variants and labile intermediate
COLORIMETRY
Routine
COLORIMETRY
Antibodies against Hb A1c (sheep antiserum)
RADIOIMMUNOASSAY (RIA)
Partial cross-reactivity w/ HbA1c
RADIOIMMUNOASSAY (RIA)
Antiserum not commercially available
RADIOIMMUNOASSAY (RIA)
Citrate agar electrophoresis (pH 6.0-6.2)
- Buffer:
Citrate agar buffer (acidic)
Citrate agar electrophoresis (pH 6.0-6.2)
- Solid support:
agarose gel
HbF migrates to the same region as HbA1
Citrate agar electrophoresis
Cellulose acetate electrophoresis (pH 8.0)
- Buffer:
Tris EDTA boric acid (alkaline)
Cellulose acetate electrophoresis (pH 8.0)
- Solid support:
cellulose acetate
Good resolution of Hb A & Hb A1
ELECTROPHORESIS
No interference from Hb variants
ELECTROPHORESIS
HbF migrates to the same region as HbA1
ELECTROPHORESIS
Scanned on high-resolution microdensitometer
ISOELECTRIC FOCUSING
Hb A1c is adequately resolved from HbA1a, A1b, S and F
ISOELECTRIC FOCUSING
ISOELECTRIC FOCUSING MEDIUM
Polyacrylamide gel
Use of affinity gel columns
AFFINITY CHROMATOGRAPHY
AFFINITY CHROMATOGRAPHY ADVANTAGES:
o No interference from non-glycosylated Hb
o Negligible interference from the labile intermediate
o Minimal dependence on variations in ambient T
Total Hb A1 MEAN %
6.5
Total Hb A1 RANGE
5.0 – 8.0
Hb A1c only RANGE
3.0 – 6.0
Hb A1c only MEAN %
4.5
HbA1c (%) =
Approximate Plasma Glucose
mg/dL
Mmol/L
For patients with inaccurate HbA1c assays (hemglobinopathies and hemolytic anemias)
o Affinity chromatography
o Immunoassays
Turnover time of serum proteins: (primary albumin) 14 to 20 days
o Reflects glycemic control over narrower period of time
Most widely used to assess short-term (3 to 6 week) glycemic control
FRUCTOSAMINE ASSAYS
FRUCTOSAMINE ASSAYS ADVANTAGE:
Use of serum samples and automated equipment (simple to perform and low in cost)
More reliable than other glycosylated protein assays
FRUCTOSAMINE ASSAYS