Cause: Implanted conceptus outside uterine cavity; intraabdominal fertilization
Pathophys:Scarred tubes (rarely uterus) slow transfer, and as a result the blastocyst implants wherever it is on day 6. Chorionic villous trophoblasts perforate basement membrane and muscle layers of tubes. If death of embryo occurs 1st, endometrium is shed and this results in brownish, modest vaginal bleeding; if trophoblast erodes 1st, this results in massive intraperitoneal bleeding
2+% of all pregnancies; 89 000/yr in US, increasing incidence (Mmwr 1995;44:46), multiple reasons including antibiotic rx of PID before sterility results. 95% are tubal; but also can be ovarian, cervical, or abdominal (0.5%)
Post-tubal ligation rate is 1/1000 over 10 yr, higher (30/1000) after electocoag tubals (Nejm 1997;336:762)
Sx:
Nearly all in 1st trimester; missed period, although withdrawal bleed may mask; most occur at about 8 wk gestation, earlier for isthmus, later for cornual
Abdominal/pelvic pain similar to menstrual/uterine pains; vaginal bleeding; shoulder pain from diaphragmatic irritation by blood
"Funny period," "funny pain," "funny pregnancy," followed by "syncope in the bathroom"
Si: Abdominal/pelvic mass (present in <50%) and tenderness; cervical tenderness if blood in pelvis; shock
Shock, surgical sterility
r/o PID, ruptured ovarian corpus luteum or follicle cyst, endometriosis cyst, appendicitis
Lab:
Chem: Serum HCG positive in all, repeat in 48 h, should double in normal pregnancy, decrease if abortion, rise slowly if ectopic. Progesterone level <25 ngm/cc
Urine: Pregnancy test positive in all with ß-HCG >50 U, and 90+% are therefore positive at 1st missed period
Xray: Ultrasound of pelvis w vaginal probe, if see intrauterine pregnancy, then dx is essentially ruled out, although the very rare circumstance of twins with one ectopic does occur
Rx:
(Nejm 2000;343:1325)
Methotrexate 50 mg/M2 im × 1 (Nejm 1999;341:1974), 91% successful overall, best if HCG <15000 mIU/cc, follow w HCG levels post rx on days 4, 7, and q 1 wk until <15 mIU; usually takes 35 d; or
Laparoscopic salpingostomy
Laparotomy for rupture w hemoperitoneum