Master the board step 3

Master the Boards: USMLE Step 3
Gestational diabetes does not present with typical symptoms of diabetes. The
vast majority of patients are diagnosed on OGTT screening.
The confirmatory test for diabetes in pregnancy is the 3 hr 100 g OGTT.
··
If the plasma glucose is > 125 mg/dL at the beginning of the test (i.e., fasting
blood glucose), diabetes mellitus is the diagnosis.
··
Abnormal plasma glucose measurements are: > 140 mg/dL at 3 hr, > 155 mg/
dL at 2 hr, and > 180 mg/dL at 1 hr.
··
If only 1 postglucose load measurement is abnormal, the diagnosis is
impaired glucose tolerance.
··
If 2 or more of the postglucose load measurements are abnormal, the diagnosis
is gestational diabetes.
··
The 1 hr 50 g OGTT is a sensitive test; it must catch all patients that may have
the disease. Sensitivity = true positives/true positives + false negatives.
··
The 3 hr 100 g OGTT is a specific test; it must catch all the people that actually
have the disease. Specificity = true negatives/true negatives + false
positives.
Give Rh(D)
immunoglobulin in Rh
negative mothers
at 28 weeks
• within 72 hours of
delivery.
• after miscarriage or
abortion.
• during amniocentesis or
CVS.
• with heavy vaginal
bleeding.
Nausea and Vomiting During Pregnancy
The following antiemetics can be used safely to relieve nausea and vomiting
during the first trimester:
··
Doxylamine
··
Metoclopramide
··
Ondansetron
··
Promethazine
··
Pyridoxine (vitamin B6)
Third Trimester Bleeding
CCS Tip: Initial steps in management of late pregnancy bleeding:
• Perform initial management:
– Get the patient’s vitals
– Place external fetal monitor
– Start IV fluids with normal saline
• Order lab tests:
– CBC
– DIC workup (platelets, PT, PTT, fibrinogen, and D-dimer)
– Type and cross-match
– Obstetric ultrasound to rule out placenta previa
422