Case 26

34 yo f h/o hypothyroidism on OCPs p/w abdominal pain x 1 day. Described as sharp pain in LLQ, radiating to RLQ, assoc w/multiple episodes of vomiting since yesterday evening. Ate Chinese food for dinner yesterday. Denies any h/a, dizziness, cp/sob, diarrhea, abnormal vaginal discharge or bleeding, flank pain, dysuria, frequency, hematuria, rash, edema. Has not had LMP recently, normally only gets every 3 months on current OCPs. Sent by ObGyn to ED for further eval.

ROS:
Constitutional: no f/c, no wt loss
Eyes: No visual changes, eye pain or discharge.
ENMT: No hearing changes, pain, discharge or infections. No neck pain or stiffness.
Cardiac: No chest pain, SOB or edema. No chest pain with exertion.
Respiratory: No cough or respiratory distress. No hemoptysis.
GI: see HPI
GU: No dysuria, frequency or burning.
MS: No myalgia, muscle weakness, joint pain or back pain.
Neuro: No headache or weakness. No LOC.
Skin: No skin rash. 

PE:
CONSTITUTIONAL: aaox3, +pallor, mild distress sec to abd pain
HEAD: Normocephalic; atraumatic.
EYES: PERRL; EOM intact. conjunctiva pale
ENT: op clear, pharynx nml
NECK: Supple; non-tender; no cervical lymphadenopathy.
CARDIOVASCULAR: tachy to 130s, reg rhythm, normal S1, S2; no murmurs, rubs, or gallops.
RESPIRATORY: CTAB
GI/GU: Normal bowel sounds; mild distended; diffuse TTP, worse across lower abdomen; no palpable organomegaly; +guarding, no rebound
BACK: non-ttp, no cvat
EXT: Normal ROM in all four extremities; non-tender to palpation; no erythema or edema; distal pulses are normal.
SKIN: +pallor, warm, dry 

QUESTIONS:

  1. A FAST was performed upon patient’s arrival. The following images below (Images A and B) were obtained. What do you notice? (RUQ, LUQ)
  2. Patient’s b-hCG was 31.31. At what b-hCG level is an IUP detectable on transvaginal US (discriminatory zone)?
  3. What is the first definitive sign of pregnancy on bedside US?
  4. What is the differential in a case of failure to identify a yolk sac/fetal pole in the uterus of a pregnant patient?
  5. Further US of the pelvis showed the following image below (Image C). What is your main concern? What is your next course of action? 

ANSWERS:

  1. Images A and B demonstrate free fluid in the RUQ and LUQ.
  2. b-HCG of 1,500 is considered the discriminatory zone, i.e. minimum quantitative level of HCG at which an intrauterine pregnancy should be seen by ultrasound.   ***However, ectopic pregnancy DOES NOT follow the rules.  If the b-HCG is not 1500, there is still a possibility of an ectopic pregnancy.  The adnexa should always be visualized to assess for a possible ectopic regardless of the b-HCG.  
  3. A gestational sac appearing as a thin walled sac within the uterus is NOT definitive evidence of an intrauterine pregnancy, as it could also represent a pseudogestational sac, which could be a decidual cyst or endometrial breakdown during an ectopic pregnancy. Definitive sonographic evidence of an intrauterine pregnancy is established when a yolk sac is identified in two planes within a gestational sac in the uterus. 
  4. -Ectopic pregnanancy
    -
    Early normal IUP
    -Abnormally developing IUP (including fetal demise, ‘an embryonic pregnancy’)
    -Active or completed miscarriage
  5. The circular ring noted in the pelvis in the setting of a positive FAST exam and a positive b-HCG is concerning for an ectopic pregnancy until proven otherwise. Your next course of action should be to stabilize patient, fluids, labs (Including T&S) and immediately involve OB/Gyn service. 
Image A

Image A

Image B

Image B

Image C

Image C