Ectopic pregnancy 03

TVUS can also detect findings that are suggestive, but not diagnostic, of ectopic pregnancy An adnexal mass (khối cạnh tử cung) is the most common ultrasound finding in ectopic pregnancy and is present in 89 percent or more of cases If TVUS is nondiagnostic, it may be because the gestation is too early to be visualized on ultrasound If so, serial measurements of the serum hCG concentration (định lượng hCG nhiều lần) should be taken until the hCG discriminatory zone is reached The ultrasound examination is also used to evaluate whether rupture of the tube or other structure has occurred A finding of echogenic fluid (consistent with blood) in the pelvic cul-de-sac (túi sau) and/or abdomen is consistent with rupture However, a small amount of fluid is present in many women and a small amount of blood may be present in other conditions (eg, spontaneous abortion) A ruptured ovarian cyst (nang buồng trứng) is another condition that is common in pregnant women and may result in a small or large amount of blood Rupture is indicated by ultrasound findings of free fluid (blood) in the abdominal cavity (dịch tự khoang màng bụng) Human chorionic gonadotropin — Measurement of hCG is performed initially to diagnose pregnancy and then followed to assess for ectopic pregnancy For follow-up, hCG is measured serially (every 48 to 72 hours) A single hCG measurement alone (định lượng hCG lần) cannot confirm the diagnosis of ectopic or normal pregnancy The initial test to diagnose pregnancy may be either a urine or serum hCG Once a pregnancy is confirmed, if ectopic pregnancy is suspected, the serum hCG is then repeated serially (typically every two days) to assess whether the increase in concentration is consistent with an abnormal pregnancy In some cases, the diagnosis of ectopic pregnancy can be made after a single measurement of hCG in combination with transvaginal ultrasound, if the hCG is above the discriminatory zone and transvaginal ultrasound shows no evidence of an intrauterine pregnancy and the presence of findings that suggest an ectopic pregnancy Studies in viable IUPs have reported the following changes in serum hCG : ●The mean doubling time for the hormone ranges (nồng độ hormon tăng gấp đôi) from 1.4 to 2.1 days in early pregnancy ●In 85 percent of viable IUPs, the hCG concentration rises by at least 66 percent every 48 hours during the first 40 days of pregnancy; only 15 percent of viable pregnancies have a rate of rise less than this threshold ●The slowest recorded rise over 48 hours associated with a viable IUP was 53 percent A serum hCG that does not rise appropriately is consistent with an abnormal pregnancy The hCG concentration rises at a much slower rate in most, but not all, ectopic and nonviable IUPs In one series, as an example, only 21 percent of ectopic pregnancies were associated with hCG levels that followed the minimum doubling time of a viable IUP (defined in this series as ≥53 percent increase over two days) A decreasing hCG concentration is most consistent with a failed pregnancy (eg, arrested pregnancy (thai ngừng tiến triển), anembryonic pregnancy (thai phôi, trứng trống), spontaneously resolving ectopic pregnancy (thai thoái triển tự nhiên), complete or incomplete abortion (sẩy thai trọn không trọn)) Discriminatory zone (ngưỡng chẩn đoán) — The discriminatory zone is the serum hCG level above which a gestational sac should be visualized by TVUS if an IUP is present Below the hCG discriminatory zone, the diagnosis of an abnormal pregnancy can be made based solely upon an inappropriately rising hCG Above the discriminatory zone, the diagnosis is made based upon the absence of evidence of an IUP on TVUS In most institutions, the discriminatory zone is a serum hCG level of 1500 or 2000 IU/L with TVUS The reported sensitivity and specificity (độ nhạy độ đặc hiệu) of hCG of >1500 IU/L are 15.2 and 93.4 percent, and for an hCG level of >2000 IU/L, they are 10.9 and 95.2 percent, respectively The level is higher for transabdominal ultrasound (approximately 6500 IU/L), but TVUS is the standard modality used to evaluate ectopic pregnancy Setting the discriminatory zone at 2000 IU/L instead of 1500 IU/L minimizes the risk of interfering with a viable IUP, if present, but increases the risk of delaying diagnosis of an ectopic pregnancy However, the correct level to use for the discriminatory zone is controversial The use of 1500 or 2000 IU/L as the discriminatory zone is based upon observations that an intrauterine gestational sac could be detected by TVUS in patients with serum hCG concentrations as low as 800 IU/L and was usually identified by expert ultrasonographers at concentrations above 1500 to 2000 IU/L In one representative study, 185 of 188 (98 percent) IUPs in women with hCG above 1500 IU/L were visualized It is important to note that there is a variation in the level of hCG across pregnancies for each gestational age and the discriminatory levels are not always reliable Another cause for variation of the discriminatory zone is that it is dependent upon the skill of the ultrasonographer, the quality of the ultrasound equipment, the presence of physical factors (eg, fibroids (u xơ), multiple gestation (đa thai)), and the laboratory characteristics of the hCG assay used  ... most consistent with a failed pregnancy (eg, arrested pregnancy (thai ngừng tiến triển), anembryonic pregnancy (thai phôi, trứng trống), spontaneously resolving ectopic pregnancy (thai thoái triển... with an abnormal pregnancy The hCG concentration rises at a much slower rate in most, but not all, ectopic and nonviable IUPs In one series, as an example, only 21 percent of ectopic pregnancies... transabdominal ultrasound (approximately 6500 IU/L), but TVUS is the standard modality used to evaluate ectopic pregnancy Setting the discriminatory zone at 2000 IU/L instead of 1500 IU/L minimizes the risk