Until there are applicable “Ottawa Rules”, RLQ evaluation will remain an art.
What does your RLQ pain work-up look like?
It’s an hour before shift change and you pick up a chart for a 20-year-old female with RLQ pain. Before you read the nurse’s notes you are already thinking there is no way you will finish the work up in the next 60 minutes and you are calculating how much you should get started. Funny how we see hundreds of these women each year and yet we all work them up a little differently. Until there are applicable Ottawa rules for the fallopian tube and the appendix, the evaluation of the right lower quadrant in women of child-bearing years remains an art. What follows are a few of my own thoughts based on some of my interpretation of the literature. Although there is a multitude of pathology that causes lower abdominal pain, the discussion will be focused on the appendix and acute gynecological disease.
1. Remember the anatomy
There is a humbling picture easily found in most anatomy books which shows the different anatomical positions of the appendix. As the appendix can literally drape over the fallopian tube or sneak behind the uterus and the visceral innervation of the appendix is the same as the ovaries and fallopian tubes, you can begin to fully appreciate the conundrum of the RLQ. Before the advent of US and CT the evaluation of these patients was truly a nightmare as there were published studies stating 45% negative appy rates in females on the one hand and studies of increased perforation rates because patients had been misdiagnosed with gynecological disease on the other. The EP was inevitably caught in a tug of war between the surgeon, the gynecologist and the elusive possibility of cervical motion tenderness. Having the appropriate consultant take ownership of the patient is now much easier with modern technology.
2. What’s the history?
Was the pain acute in onset? My differential of acute onset of pain focuses on vascular emergencies (think of the four horsemen ripping, bursting, twisting and occluding), the blockage of a solid organ causing distention and spasm, and irritation from something bursting. Appendicitis usually is lower on this list as classical appendicitis starts gradually and only results in localized pain when the appendix is grossly inflamed and irritating the somatic innervated peritoneal wall. In their rational clinical exam series JAMA (Wagner JM, Nov 1996) looked at history and physical findings that were more common in appendicitis and found that only the presence of right lower quadrant pain, rigidity and history of migration significantly increased likelihood ratios that the patient had appendicitis. Things that make me lean towards a gynecological etiology include multiple episodes of recurrent pain, the history of previous infection or current heavy discharge, pain that has lasted and not progressed for more that 3 days, and if the patient is gobbling down Fritos when I walk into the room. Besides the obvious questions that focus on the possibility of pregnancy I also like to calculate where the patient is on her cycle because a ruptured cyst creeps higher into my differential if they are mid cycle or expecting their period.
3. The exam.
This is where the first division appears to occur in the EP work up as there is variation in opinion of how much of an exam is adequate. In the perfect world this would be a mute point, but in many of our overcrowded departments the ability to get the patient into a private room for a full examination sometimes requires more choreography than Dancing with the Stars.
First the rectal, there are studies out there that suggest if you have localized pain in the RLQ and a story consistent with appendicitis that the rectal exam really offers little more to the work up. The counterpart to this is that there are also lawsuits in cases of missed appendicitis which suggest that the physician’s exam was inadequate because the rectal was not done. Theoretically patients with retrocecal appendicitis may not have significant RLQ pain as their inflamed appendix is shielded by their colon but may have localized pain with rectal exam. Personally, I think it is a very special patient that can differentiate that “localized” pain from the general discomfort of the exam itself, and that a CT is much more sensitive than our fingers. Still, rather contradictory I have to admit, if I can get the patient into a room, I’ll usually do a rectal exam looking for masses and blood (as inflammatory bowel disease is often in the differential), and most importantly so that it eliminates the possibility that someone else might have to do one later.
Now, what about the pelvic exam? Some of my colleagues are very comfortable pursuing the work up of appendicitis in a non-pregnant woman of child bearing age with a good story for appendicitis without a pelvic exam. Their reasoning is that appendicitis is at the top of their differential and that if the CT doesn’t show appendicitis that a pelvic exam can always be done later (which usually translates into the next shift). Some of my residents are also quick to point out the futility of most aspects of the pelvic exam based on several journal club articles. Close (West J Med 2001;175) showed that the reliability of the pelvic exam for an abnormal finding between two EP physicians is extremely low; Carter (J of Reproductive Medicine 1994, 39) showed that US is much more sensitive than bimanual with greater than 50% of pelvic masses being missed by bimanual. And finally, Padilla (Obstet Gynecol 2000;96) showed that there was extremely poor correlation between exam findings- regardless of training level of the examinee- and laparotomy findings when multiple pelvic exams were done on women under general anesthesia prior to their pelvic laparotomies. I would love to have seen that IRB consent form.
So essentially the pelvic exam has poor reproducibility and is poorly associated with US or surgical findings. So why do I feel that this is still an important part of the initial physical exam? Personally, I use it to guide which imaging study I will pursue first. If I can get the patient in the pelvic room I’ll do a full speculum exam with cultures. Realistically, if the story really sounds more GI and the gyn room is not readily available I may do a bedside bimanual and use the newer Chlamydia and Gonorrhea urine tests if there is any discharge. Whenever I do a pelvic exam I am careful to try and not bait my questions. I try and avoid “is this uncomfortable?” and replace it with “In comparison to previous exams how uncomfortable is today’s exam?” because like the rectal, no pelvic exam is ever “comfortable”. About a quarter of women with appendicitis can have cervical motion tenderness but lots of discharge and bilateral adnexal pain or the finding of an impressively enlarged uterus (or positive pregnancy test) leans me towards ultrasound. Isolated RLQ pain in an otherwise unremarkable exam makes me start with CT. If there is still any question, I order the ultrasound while giving the patient their first drink of contrast.
4. The lab work up.
CBC, hcg and urine. If the urine dip is really dirty and there is any vaginal discharge I consider a clean cath. Conversely, if a urine Chlamydia or Gonorrhea probe is used remember that these should be done on unwiped dirty specimens. As the appendix can lie over the ureter you can see a few white blood cells in the urine with appendicitis.
Plain films are generally not helpful and most of us have limited access to MRIs so the major options are ultrasound and CT.
Ultrasound. The advantages of ultrasound are: limited prep time (though trans abdominal ultrasounds usually require a full bladder), ability to correlate exam findings with area of greatest pain, decreased cost, no radiation and better visualization of most gynecological pathology. Sensitivities vary between 75–90% but there is a 90% positive predictive value if an abnormal appendix is visualized that it represents true appendicitis. Its disadvantages include that it is very operator dependent and that obesity, prior surgery, and inability to compress due to increased air bowel gas or significant pain may decrease accuracy. It is also very difficult to see a normal appendix or even a recently perforated appendix. Therefore a “normal” ultrasound doesn’t rule out appendicitis.
CT scan. Advantages include: decreased operator dependency, increased visualization of the appendix and other abdominal organs leading to better accuracy in the inclusion and exclusion of appendicitis. Most CT studies show sensitivities and specificities in the mid to high 90’s. Disadvantages include: cost, significant prep time, and radiation exposure.
A few additional comments on radiation exposure are noteworthy. There is an excellent article by Richard Semelka (Medscape Feb. 16, 2007) which examines the current views on cancer risks with CT exposures. Most abdominal pelvic CT scans expose patients to about 10 mSieverts of radiation; it is believed that even this small amount could eventually lead to cancer in 1 in every 1000 scanned patients. The cancers associated with medical radiation include leukemia, thyroid, and breast and usually show up 15–20 years later. These absolute risks are theoretical and based mostly on information extrapolated from atomic bomb victims during WWII. But patients who receive multiple CT’s throughout their lifetime are reaching comparable levels to these radiation fallout victims. If you have any doubts about this, just think how many scans the last patient you saw with renal colic has had over the past two years. I’d like to advocate that as a specialty, we need to develop policies to scan more prudently. Some institutions have already begun to develop protocols in patients with recurrent kidney stones utilizing ultrasound ( Karta EM J May 2006) or at least a modified low dose radiation CT (Tack AJR Feb 2003). Concerning appendicitis, from large population studies we know that men with a classic story for appendicitis usually have a greater than 90% chance of having actual appendicitis yet at many institutions these men are blindly scanned prior to any surgical involvement. We developed a protocol at our teaching institution that surgeons would evaluate these patients prior to a CT scan and the scan would only be ordered in cases the surgeon felt was equivocal. Of course this doesn’t always happen, but it is a good reminder to all of us that in at least some cases appendicitis is really still a clinical diagnoses.
There are several different ways that the CT scan can be done. A few centers use non-contrasted scans, their advantage is that there is no prep time and a vomiting patient doesn’t need to drink the contrast. The downsides are that many radiologists are not comfortable interpreting these studies and that in patients with limited periappendiceal fat, signs of an abnormal appendix may be missed. Most academic departments appear to use oral and IV protocols. Ideally the oral contrast will fill the cecum and delineate the appendix and the IV contrast may pick up early inflammatory changes in the appendiceal wall. Downsides are long prep time and dye exposure. Our institution uses oral contrast without the IV contrast because our radiologists feel the IV contrast adds little additional advantage. We also occasionally use rectal contrast CT with its advantageous quicker prep time, ease of administration in the vomiting patient and shorter ED length of stay. Although some institutions have had great success with this technique we have found its use to be limited by patient and technician preferences. The scans can be messing so often our techs will scan other patients first and still give our patient an oral drink, thus negating some of its intended advantages and some patients just don’t tolerate the rectal pressure well. Whatever scanning technique is chosen it is important to remember that a negative CT scan doesn’t absolutely rule out appendicitis especially if it is in its early stages. All patients who are discharged should be given adequate abdominal precautions and instructions to be reevaluated if symptoms don’t improve in the next 12–24 hours.
Jeannette Wolfe, MD, is an assistant professor of emergency medicine at Tufts School of Medicine and a practicing physician at the Baystate Medical Center in Springfield, Massachusetts.