UW+Mehlm AFP levels 03-25 (2) Flashcards
(29 cards)
UW. table. Decr. AFP? 1
Aneuploidies, eg 18 or 21
UW. table. Incr. AFP? 3
Open neural tube defects (eg anencephaly, open spina bifida)
Ventral wall defects (eg omphalocele, gastrochisis)
Multiple gestations
UW. what produces AFP?
protein produced by the fetal liver and gastrointestinal tract
UW. where is present AFP?
present in fetal serum and amniotic fluid.
It is absorbed into the maternal circulation.
UW. quad screening for what?
screening test for fetal aneuploidy and congenital defects
UW. AFP incr in multiple gestations why?
due to greater fetal tissue volume capable of producing AFP
UW. AFP incr. in inaccurate pregnancy dating (because AFP fluctuates with gestational age).
.
UW. AFP incr. in inaccurate pregnancy dating. Pagal kad tipo ziurim kad butu accurate?
eg last menstrual period is consistent with fundal height
UW. Case - one baby + accurate pregnancy datings. Elevated AFP. Cause?
elevated AFP level suggests a congenital defect
UW. abdominal and neuro tube defects allow for greater leakage of AFP into the amniotic fluid, which elevates AFP levels.
.
UW. further evaluation post quad test?
Further evaluation is with an ultrasound to evaluate fetal anatomy and confirm pregnancy dating.
UW. In what other cases in adult can be incr. AFP?
liver disease (eg, HCC, viral hepatitis) and ovarian germ cell tumors (eg, endodermal sinus tumors, embryonal carcinoma).
This patient (in case) has no symptoms of liver disease (eg, ascites, jaundice) or of an ovarian germ cell tumor (eg, abdominal distension and pain), making a fetal etiology more likely.
Mehl. Most common cause of abnormal AFP measurement is ???
“dating error.”
Mehl. The USMLE Q will tell you that a pregnant woman has AFP measured 2.6 times the upper limit of normal for her gestational age; next best step =??
“ultrasound”!!!!!!!!!!! [to confirm pregnancy dating]
wrong - “re-measure AFP”
Mehl. “re-measure AFP” is wrong because - AFP value measured by the lab isn’t wrong; it’s merely that the estimated gestational age of the pregnancy is wrong. An ultrasound will allow for a re-measuring of the crown-rump length (CRL), which is a typical method for ascertaining approximate gestational age.
.
Mehl. apart from dating error also can be increased. Classic cause?
Apart from dating error, classic cause is neural tube defects (i.e., spina bifida).
Mehl. Other causes of incr. AFP for usmle are…?3
anencephaly, multiple gestation pregnancies, and omphalocele / gastroschisis.
Mehl. too low AFP. Case?
As discussed before, AFP is “down in Down syndrome.”
It’s also low in Edward and Patau but USMLE doesn’t care.
UW. 29y.o + 16 weeks. uterus 20 weeks gest. ALP - 3,8 multiples normal. Best next step?
FETAL ULTRASOUND
UW. neural tube defects. Risk factors? 4
low folic acid;
methotrexate, entiepilectis
DM
prior pregnancy with neural tube defects
UW. neural tube defects. prenatal screening. 2
AFP
2nd trimester UG
UW. neural tube defects. prevention in average risk?
0,4 mg folic acid daily
UW. neural tube defects. prevention in high risk?
4 mg folic acid daily
UW. neural tube defects. when is performed screening for these pathologies?
2nd trimester, 15-20 weeks