Digest of Dr. Herbert’s Monthly Audio CME Series: Ectopic Pregnancy,

How to rule out an ectopic pregnancy in women who present with first trimester vaginal bleeding or pelvic pain.

Step 1: Use ultrasound to rule in an intrauterine pregnancy (IUP). Definite ultrasonographic evidence of an IUP is the presence of a fetal pole and fetal cardiac activity. If a double ring sign is seen around the gestational sac, this is good evidence of an IUP. If only a single ring is seen, the ultrasound is deemed indeterminate.
Step 2: Obtain a quantitative ß-hCG and compare this to the discriminatory zone (DZ), which is the ß-hCG level where a IUP should be seen within the uterus. If the ß-hCG is greater than the DZ (usually 1,500) and an IUP is not seen, then the patient likely has an ectopic pregnancy. On the other hand, if the ß-hCG is less than the DZ, then the differential includes normal pregnancy and ectopic.
Step 3: Admit or discharge. Stable, low risk patients i.e. patients with low B-hCG that have no current evidence of ectopic on U/S can be safely discharged home to follow-up with their OB in 48 hours for a repeat quantitative ß-HCG and ultrasound.

2. Post-Methotrexate management of ectopic pregnancy
Medical therapy using methotrexate (MTX) for the treatment of ectopic pregnancy is very safe, easy to administer, and is being used more often. These patients may return to the emergency department with continued or worsening abdominal pain. Pain develops normally as part of MTX therapy because of cell lysis. The dilemma for the emergency physician is differentiating the normal post-MTX pain versus a ruptured ectopic pregnancy. The emergency physician must rule-out a rupturing ectopic by first using an ultrasound to asses for free fluid. Next, serial hemoglobins can be compared to prior visits. The ß-hCG remains elevated in the first few days after initiation of MTX therapy and is therefore not helpful early in the course. However, if the patient presents 1-2 weeks after MTX and the quantitative ß-hCG is persistently elevated, these patients are at high risk for a ruptured ectopic and should be evaluated by obstetrics emergently.

3. Physician bias and how it can blind you
Three common physician biases are discussed in relation to emergency department bounceback patients.

Bias: Anchoring Bias
A.K.A: First impressions, jumping to conclusions
Description: The physician fixates on specific features of a presentation too early in the diagnostic process
Consequence: Premature closure of thinking and patient is labeled with the incorrect diagnosis
Avoiding strategy: Ignore the obvious, at least initially. Delay forming an impression until more complete information is obtained

Bias: Confirmation bias
A.K.A: Following hunches, positive testing
Description: When a hypothesis is developed on relatively weak or ambiguous data, it may later interfere with superior and more plentiful data.
Consequence: Wasted time and effort and may completely miss the diagnosis
Avoiding strategy: Try to prove yourself wrong. Seek out disconfirming evidence that will challenge the hypothesis; check that competing diagnoses have been given adequate consideration

Bias: Diagnosis momentum
A.K.A: Diagnostic creep
Description: The process starts with a non-medical opinion of what the source of the patient’s symptoms may be and is passed on from person to person gathering momentum until it appears almost certain by the time the patient sees a physician.
Consequence: Allowing the wrong label to stay on a patient may seal his or her fate
Avoiding strategy: Make up your own mind. Be cautious about any patient that comes pre-diagnosed (especially at change of shift), all evidence should be reviewed to ensure concurrence
Source: Academic Emergency Medicine 2002;9:1184-1204

4. Unanticipated death after discharge from the emergency department
This study review looked at a cohort of ED patients that were discharged home and had an unexpected death within 7 days of their ED visit. Of the 117 cases that were found, 58(50%) were related to the ED visit and 35 (60%) of these had a possible error. Four themes repeatedly emerged from these cases:
-Atypical presentation of an unusual problem
-Chronic disease with decompensation
-Abnormal vital signs
-Mental disability or psychiatric problem or substance abuse that may have made it less likely that the patient would return for worsening symptoms.
Source: Annals of Emergency Medicine 2007;49:735-745

5. Is aortic dissection on your radar?
We all learned from medical school that the classic story for aortic dissection was sudden onset tearing chest pain that radiates to the back with unilateral absent pulses and a new murmur, but this is probably the minority of cases. For example, in the IRAD study (JAMA 2000;283), 13% of patients had syncope as their only complaint and denied chest pain or back pain. Dissection should also be considered in the acute stroke patient prior to thrombolytics. If these patients have symptoms of chest or back pain then a screening chest X-ray should probably be obtained. The intima may also dissect into the right coronary ostia causing what may appear as an inferior MI. This event occurs in only 1/100 dissections and should not delay definitive treatment if suspicion for dissection is low. Therefore, be wary of the “chest pain and…syndrome”. If a patient presents with chest pain and stroke, or chest pain and abdominal pain, or chest and another complain, think of aortic dissection.

Source: Discussions with Dr. Rob Rogers