The management of abdominal pain has changed significantly in the past 20 years, with increasing emphasis on identifying patients who are at high risk for occult pathology and worse outcomes. Emphasizing safe disposition over diagnosis, this issue identifies the important aspects of the history and physical examination, explores strengths and weaknesses of laboratory evaluations, and summarizes the pros and cons of the many types of imaging now available. With abdominal pain still the most common chief complaint seen in the emergency department, a new look at the evolution of assessment strategies is in order, such as new recommendations on the use of oral contrast, managing HIV patients on highly active antiretroviral therapy, maximizing use of bedside ultrasound, when and how to offer pain relief, and the value of serial examinations and observation to reduce costs and improve care.
As you begin your shift, a 68-year-old woman presents with severe abdominal pain. She requires 4 mg of morphine before you can even talk to her. Surprisingly, her abdomen is soft, and not particularly tender. She is tachycardic to the 120s, and her pulse feels irregular. Her blood pressure is 100/50 mm Hg. It seems strange that her pain is so incongruent with her exam, and you wonder: What is the best imaging study to help clarify things?
In the next room, a 24-year-old man with no past medical history has presented with sudden, severe left lower quadrant pain followed by vomiting. He has normal vital signs except for tachycardia and a nontender abdomen. He seems too young to have diverticulitis, and since the pain is on the left side, you doubt appendicitis. A urinalysis is negative for blood, making renal colic less likely. Pain medication helps, and you wonder whether this is just gas or further diagnostic testing is needed…
An experienced emergency clinician might compare the painful abdomen to the dark side of the moon—a terrain both indistinct and enigmatic. The patient’s history is frequently uncertain and the physical examination misleading. To further complicate the issue, “textbook” presentations of serious disease seem to exist only in print. After an extensive workup, patients with severe pain may prove to have gastroenteritis, while those with a seemingly benign belly are hiding a surgical catastrophe.
This 20th anniversary issue of Emergency Medicine Practice will once again address the dilemma of abdominal pain and take another look at the structured approach to this complaint. The central principles include: (1) recognizing the high-risk patient, (2) selecting appropriate testing, and (3) using flexible clinical pathways. This issue emphasizes disposition over diagnosis, as it is not as important to identify an exact cause of abdominal pain as it is to recognize a surgical abdomen.
The broad scope of abdominal pain makes it less amenable to the large randomized double-blind studies seen with sepsis, stroke, or pulmonary embolism. Much of the emergency medicine literature focuses on incidence, causes, and misdiagnosis of abdominal pain. Some researchers concentrate on radiation-reduction strategies or clinical scoring systems to detect a particular cause of abdominal pain (such as appendicitis). The American College of Emergency Physicians Clinical Policy on acute abdominal pain has been “retired,” being last updated almost 20 years ago. For this update, except for the most common and deadly conditions, articles were chosen based more on clinical presentation and emergency evaluation of abdominal pain rather than on specific etiologies of abdominal pain.
1. “I didn’t think she needed a CT.”
The CT scan is the most revealing tool in the ED workup. Maintain a low threshold for obtaining CT in acute abdominal pain in the elderly.
7. “I thought it was just gastroenteritis.”
It is preferable to give a diagnosis of “nonspecific abdominal pain,” “undifferentiated abdominal pain,” or “abdominal pain of unknown etiology” than to assign a specific but unsupported diagnosis. A true diagnosis of gastroenteritis requires nausea, vomiting, and diarrhea.
9. “The pain was in the wrong spot!”
Consider the diagnosis of appendicitis in patients with right flank and right upper quadrant pain (and also left lower and, rarely, left upper quadrant pain). Patients with retrocecal appendicitis present with minimal or no right lower quadrant tenderness.
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study is included in bold type following the references, where available. In addition, the most informative references cited in this paper, as determined by the author, are highlighted.
Jeff: Welcome back to EMplify the podcast corollary to EB Medicine’s Emergency medicine Practice. I’m Jeff Nusbaum and I’m back with Nachi Gupta for your regularly scheduled monthly dose of evidence based medicine. This month, we are tackling an incredibly important topic – Assessing abdominal pain in adults, a rational, cost effective, and evidence-based strategy.
Nachi: This incredibly important topic was chosen to mark the 20th anniversary of Emergency Medicine Practice. It is actually a revision of the first issue of Emergency Medicine Practice in 1999, now with updated evidence and recommendations. Thanks Robert Williford and Dr. Colucciello for getting this all started 2 decades ago!
Jeff: Wow – 20 years – that’s amazing considering Emergency Medicine as a specialty hadn’t even been around all that long at the time and as Dr. Jagoda writes in his intro “evidence based education was still finding its footing.”
Nachi: As a tribute to the man who started it all, EB Medicine again turned to Dr. Colucciello, who is no longer wearing his editor in chief hat, but instead is a professor at the University of North Carolina School of Medicine, to update his original article with the latest evidence.
Jeff: Before we dive into the meat and potatoes of this month’s issue, let me also recognize Drs. Taylor and Shaukat of Emory and Coney Island Hospital respectively for their efforts in peer reviewing this huge topic.Show More v
Nachi: For a number of reasons, this month is going to be a little different. You will notice that we will focus more on safe disposition instead of on diagnosis. Which is reasonable, as that is the crux of our job as emergency physicians.
Jeff: Indeed. So for those of you who can’t wait, here’s a quick spoiler, The CBC isn’t all that useful. CT is good but you really should learn ultrasound, and lastly, sick patients need prompt consultation and resuscitation, not rapid trips to radiology.
Nachi: All valid points, but let’s dive in too some actual detail.
Jeff: Abdominal pain is the one of most frequent complaint in US emergency departments, representing 8% of all adult ED visits, with admission rates for all patients with abdominal pain ranging between 18-42% and reaching as high as 60% for the elderly.
Nachi: With respect to the elderly, statistically speaking, 20% presenting with abdominal pain will undergo surgery, and 5% will die.
Jeff: Often the etiology of the abdominal pain is never determined. This happens up to 40% of the time by the end of the ED visit.
Nachi: I feel like that needs to be restated for emphasis – nearly half of patients who present to the ED with abdominal pain will have no determined etiology for their pain. Clearly, that doesn’t mean you are a bad ED physician – it’s just the way it goes.
Jeff: Definitely still a win to be told you aren’t having an intra-abdominal catastrophe at the end of your visit!
Nachi: Moving on to pathophysiology. Visceral pain results from distention or inflammation of the hollow organs or from ischemia from any internal organ, while the more localized, somatic pain is typically from irritation of the adjacent peritoneum.
Jeff: And don’t forget about referred pain. Due to the movement of organs and stretching of nerve pathways during fetal development, pain may be referred to distant sites, like diaphragmatic irritation presenting as shoulder pain.
Nachi: Let’s talk differential diagnosis. The differential for abdominal pain is tremendously broad and includes both intra-abdominal and extra abdominal pathologies. Check out table 2 for a very thorough list.
Jeff: Table 1 is also worth reviewing while you’re on page 3 as it lists a few of the common dangerous mimics that often lead to misdiagnosis on initial presentation. To highlight a few – a AAA can masquerade as renal colic, diverticulitis, or a lumbar strain; an ectopic may present similar to PID, a UTI, or a corpus luteum cyst, and mesenteric ischemia may present shockingly similar to gastroenteritis, constipation, ileus, or an SBO.
Nachi: Though misdiagnosis is certainly possible at any age, one must be particularly cautious with the elderly. Abdominal pain in the elderly is complicated by a number of factors, they often have no fever, no leukocytosis, or no localized tenderness despite surgical disease, surgical problems progress more rapidly, and lastly, they are at risk for vascular catastrophes, which don’t typically afflict the younger population
Jeff: Dr. Colucciello closes the section on the elderly with a really thought-provoking point – we routinely admit 75 year old with chest pain and benign exams, yet we readily discharge a 75 year old with abdominal pain and a benign exam even though the morbidity and mortality of abdominal pain in this group exceeds that of the chest pain group.
Nachi: That’s an interesting perspective, but we still have to think about this in the context of what an admission would offer in either of these cases. Most of the testing for abdominal pain can be done in the ED, CT being the workhorse. This point certainly merits more thought though.
Jeff: Most clinicians have a low threshold to scan their elderly patients with abdominal pain, and the data behind this practice is quite compelling. In one study, CT altered the admission decision in 26%, need for surgery in 12%, the need for antibiotics in 21%, and changed the suspected diagnosis in 45%.
Nachi: That latter figure, 45% change in suspected diagnosis, that was also confirmed in another study in which CT revealed a clinically unsuspected diagnosis in 43% of the elderly.
Jeff: And it’s worth mentioning, that even though CT may be the go-to-tool - biliary tract disease, which we know is best visualized on ultrasound, is actually the most common cause of abdominal pain, especially sudden onset abdominal pain in the elderly.
Nachi: The next higher risk group to discuss are patients with HIV. While anti retroviral therapy has certainly decreased the burden of opportunistic infections, don’t forget to keep a broader differential in this group including bacterial enterocolitis, drug-induced pancreatitis, or AIDS related cholangiopathy
Jeff: Definitely make sure to check to see if the patient has a recent CD4 count to give you a sense of their disease and what they may be at risk for. At less than 200, cryptosporidium, isospora, cyclospora, and microsporidium all make their way onto the differential in addition to the standard players.
Nachi: For more information on HIV and its management, check out the February 2016 issue of Emergency Medicine Practice, which covered this and more in depth.
Jeff: The next high risk population we are going to discuss are women of childbearing age. Step one is always the same - diagnose pregnancy! Always get a pregnancy test for women between menarche and menopause.
Nachi: The pregnancy test is important not only for diagnosing an intrauterine pregnancy, but it’s also a reminder, that we need to consider and rule out an ectopic.
Jeff: Along similar lines, you also need to consider torsion, especially in your pregnant population, as 20% of cases of ovarian torsion occur during pregnancy.
Nachi: Unfortunately, you cannot rely on the physical exam alone in this age group, as the pelvic exam may be misleading. Up to a quarter of women with appendicitis can exhibit cervical motion tenderness -- a finding typically associated with PID. Sadly, errors are common and ⅓ of women of childbearing age who ultimately were found to have appendicitis were initially misdiagnosed.
Jeff: To help reduce your risk in the pregnant population, consider imaging, particularly with radiation reduction strategies, including using ultrasound and MRI, which is gaining favor in the diagnosis of appendicitis in pregnancy.
Nachi: Diagnosis of appendicitis, in a pregnant patient, ultrasound vs. mri. Sounds familiar. Didn’t we just talk about this in Episode 24 back in January?
Jeff: We sure did! Take another listen if that doesn’t ring a bell.
Nachi: That was focused on first trimester only, but while we’re talking about appendicitis in pregnancy - keep in mind that during the second half of pregnancy, the appendix has moved out of the RLQ and is more likely to be found in the RUQ.
Jeff: As yes, the classic RUQ appendix. As if our jobs weren’t hard enough, now anatomy is changing… Anyway, the last high risk group we are going to discuss here are those patients with prior abdominal surgery. Make sure to ALWAYS examine the patient's exposed skin to look for scars. Adhesions are the leading cause of SBOs in the industrialized world, followed by malignancy, IBS, and internal or external hernias.
Nachi: Also keep a high index of suspicion for patients who have undergone bariatric surgery. They are especially prone to surgical causes of abdominal pain including skin infections and surgical leaks.
Jeff: For this reason, CT imaging should be done with IV and oral contrast, with those having undergone a Roux-en-Y receiving oral contrast on the CT table.
Nachi: Perfect. Let’s move on to evaluation once in the ED!
Jeff: As we mentioned a few times already - diagnosis is difficult, a comparison of initial and final diagnosis only has about 50-65% accuracy. For this reason, Dr. C suggests taking a ‘worst first’ approach to forming your differential and guiding your workup.
Nachi: And as a brief aside, before we continue… Missed appendicitis is one of the three most common causes of emergency medicine malpractice lawsuits - with MI and fractures being the other two. That being said, you, as a clinician, have either missed appendicitis or likely will in the future. In a study of cases of misdiagnosed appendicitis brought to litigation, several themes recurred. For example, patients with misdiagnosed disease has less RLQ pain and tenderness as well as diminished anorexia, nausea, and vomiting.
Jeff: Well that’s scary - I know I’ve already missed a case, but luckily, he returned thanks to good return precautions, which we’ll get to in a few minutes. Also, note that in addition to imaging and the physical exam, history is often the key to uncovering the cause of abdominal pain.
Nachi: Not to harp on litigation, but in malpractice cases brought up for failure to diagnose abdominal conditions, deficiencies in data gathering and charting were often to blame rather than misinterpretation of data.
Jeff: As no shocker here, getting a complete history remains tremendously important in your practice as an emergency clinician. A recurring theme of EMplify for sure.
Nachi: In order to really nail this down, consider using a standardized history form -- or memorizing one. An example is shown in Table 1. Standardized forms have been shown to improve patient satisfaction and diagnostic accuracy.
Jeff: An interesting question for your abdominal pain patient is to ask about the ride to the hospital. Experiencing pain going over a speed bump has been shown to be about 97% sensitive and 30% specific for appendicitis. So fairly sensitive, but not too specific.
Nachi: That’s interesting and may help guide you, but it’s certainly no replacement for CT. And remember that you can have stump appendicitis. This can occur in the appendiceal remnant after an appendectomy and is found in about 0.15% of all appendectomies.
Jeff: Alright, so on to the physical exam. Like always, let’s start with vital signs. An elevated temp can be associated with intra abdominal infection, but sensitivity and specificity vary greatly here. Always consider a rectal temp, as these are generally more reliable.
Nachi: And remember that hypothermic patients who are septic have worse outcomes than those who are hyperthermic and septic.
Jeff: Elevated respiratory rate can be due to pain or subdiaphragmatic irritation. However, it can also be due to hypoxia, sepsis, anemia, PE, or metabolic acidosis, so consider all of those also in your differential.
Nachi: Moving on to blood pressure: frank hypotension should make you immediately think of a ruptured AAA or septic shock 2/2 an intra abd infection. You can also use the shock index, which as a reminder is simply the HR/SBP. In one study, a SI > 0.7 was sensitive for 28-day mortality in sepsis.
Jeff: Speaking of HR, tachycardia can be a response to pain, anxiety, fever, blood loss, or sepsis. An irregularly irregular rhythm -- or a fib -- is an important risk factor for mesenteric ischemia in elderly patients. This is important to consider in your differential early as it may guide your imaging modality.
Nachi: With vitals done, we can move on to the abdominal exam - it is rare that a serious abdominal condition will present without tenderness in a young adult patient, but remember that the elderly patient may not present with much tenderness at all due decreased peritoneal sensitivity. Abdominal tenderness that is greatest when the abdominal muscles are contracted is likely due to abdominal wall pain. This can be elicited by having the patient lift their head or let their legs off the bed. This finding is known as Carnett sign and is about 95% accurate for distinguishing abdominal wall pain from visceral abdominal pain.
Jeff: Though tenderness itself is helpful, the location of tenderness can be misleading. Note that while 80% of patients with appendicitis have RLQ tenderness, 20% don’t. The old 80-20 rule! So definitely don’t let RLQ tenderness be your sole guide!
Nachi: Voluntary guarding is due to fear, anxiety, or even a reaction to a clinician’s cold hands. Involuntary guarding (also called rigidity) is more likely to occur with surgical disease. Remember that rigidity may be a less common finding in the elderly despite surgical disease.
Jeff: Peritoneal signs are the true hallmark of surgical disease. These include rebound pain, pain with coughing, pain with shaking the stretcher or pain with striking the patient’s heel. Rebound historically has been thought to be pathognomonic for surgical disease, but recent literature hasn’t found it to be all that useful, with one study claiming it has no predictive value.
Nachi: As an alternative, consider the “cough test”. Look for evidence of posttussive abd pain (like grimacing, flinching, or grabbing the belly). Studies have found the cough sign to be 80-95% sensitive for peritonitis.
Jeff: In terms of other sings elicited during the abdominal exam: The murphy sign, ruq palpation that causes the patient to stop a deep inspiration -- in one study had a sensitivity of 97%, but a specificity of just under 50%. The psoas sign, pain elicited by extending the RLE towards the back while the patient lies on their left side -- in one study had a specificity of 95%, but only had a sensitivity of 16%.
Nachi: Neither the obturator sign (pain with internal rotation of the flexed hip) nor the rosving sign (pain in the RLQ by palpating the LLQ) have been rigorously studied.
Jeff: Moving a bit further south, from the abdomen to the pelvis - let’s talk about the pelvic exam. Most EM training programs certainly emphasize the importance of the the pelvic exam for women with lower abdominal pain, but some recent papers have questioned its role. A 2018 study involving 288 women 14-20 years old found that the pelvic didn’t increase sensitivity or specificity of diagnosis of chlamydia, gonorrhea, or trichomoniasis when compared with history alone. Another study questioned whether the pelvic exam can be omitted in these patients with an early intrauterine pregnancy confirmed on ultrasound, but it was unable to reach a conclusion, possibly due to insufficient power.
Nachi: While Jeff and I do find it valuable to elicit as much as information from the history as possible and take value in the possibility of omitting the pelvic in certain cases in the future, given the current evidence based medicine, we both agree with the author here. Don’t abandon the pelvic for these patients just yet!
Jeff: While on this topic, we should also briefly mention a reminder about fitz-hugh-curtis syndrome, perihepatic inflammation associated with PID.
Nachi: As for the digital rectal exam, this can certainly be of use when considering and diagnosing prostatitis, perirectal disease, stool impactions, rectal foreign bodies, and gi bleeds.
Jeff: And let’s not forget the often overlooked scrotal and testicular exam. In men with abdominal or flank pain, this should always be considered. Testicular torsion often presents with isolated abdominal or flank pain. The scrotal exam will help diagnose inguinal and scrotal hernias.
Nachi: Getting back to malpractice case reviews for a minute --- in a 2018 review involving testicular torsion, almost ⅓ of the patients with missed torsion had presented with abdominal pain --- not scrotal pain! In ⅕ of the cases, no testicular exam was performed at all. Also, most cases of missed torsion occured in patients under 25 years old.
Jeff: Speaking of torsion, about 6% occur over the age of 31, so have an increased concern for this in the young. Of course, if concerned for torsion, consult urology immediately and consider manual detorsion.
Nachi: And if you, like me, were taught to manually detorse by rotating in the lateral or open book direction, keep in mind that in a study of 200 males with torsion, ⅓ had rotated laterally, not medially.
Jeff: Great point. And one last quick point here. Especially if you are unsure about the diagnosis, make sure to perform serial exams both in the ED and also in the next few days at their PCP’s office. In one study, a 30 hour later repeat exam for patients discharged with nonspecific abdominal pain resulted in a clinically relevant change in diagnosis and therapy in almost 25% of patients.
Nachi: So that wraps up the physical. Let’s get into diagnostic studies, starting with lab work and everybody’s favorite topic... the cbc.
Jeff: Yup, just the other day I was asked by a consultant “what’s the white count.” in a patient with CT proven appendicitis. Man, a small part of my soul dies every time this happens.
Nachi: It appears you must have an evidenced based soul then. According to a few studies, anywhere from 10-60% of patients with surgically proven appendicitis have an initially normal WBC. So in some studies, it’s even worse than a coin flip.
Jeff: Even worse, in children the CBC is less helpful. In children, an elevated WBC detects a mere 53% of severe abdominal pathology - so again not all that helpful.
Nachi: That being said, at the other end of the spectrum, in the elderly, an elevated WBC may imply serious disease.
Jeff: So let’s make this perfectly clear. A normal WBC should not be reassuring, but an elevated WBC, especially in the elderly, should be very concerning.
Nachi: The CRP is up next. Though not used frequently, it’s still worth mentioning, as there is a host of data on it in the setting of abdominal pain. In one meta analysis, CRP was approximately 62% sensitive and 66% specific for appendicitis.
Jeff: And while lower levels of CRP do not rule out positive findings, increasing levels of CRP do predict, with increasing likelihood, the chances of positive findings.
Nachi: Next we have lipase and amylase. The serum lipase is the best test for suspected pancreatitis. The amylase adds limited value and should not be routinely ordered.
Jeff: As for the lactate. The greatest value of a lactate level is to detect occult shock and sepsis. It is also useful to screen for visceral ischemia.
Nachi: And the last lab test we’ll discuss is the UA. The urinalysis is a potentially misleading test. In two studies, 20-30% of patients with appendicitis also had hematuria with leukocytes and bacteria on their UA. In a separate study of those with a AAA, there was an 87% incidence of hematuria.
Jeff: That’s pretty troubling. Definitely not great to diagnosis someone with hematuria and a primary GU problem, when their aorta is actually exploding.
Nachi: And that’s a great reminder to always avoid premature diagnostic closure.
Jeff: Also worth mentioning is that not all ureteral stones present with hematuria. At least 6% have no hematuria on microscopy.
Nachi: Alright, so that brings us to imaging. First up: plain films. I’m going to quote this directly from the article since I think it's so important, ‘never rely on plain films to exclude surgical disease.”
Jeff: This statement is certainly evidence based as in one study 40% of x-ray findings were inconsistent with the final diagnosis. In another study, 43% of patients with major surgical disorders had either normal or misleading plain film results. So again, the take home here is that XR cannot rule out surgical disease, and should not be routinely ordered except for in specific settings.
Nachi: And perhaps the most important of all those settings is in the setting of possible free air under the diaphragm. In this case, an upright chest visualizing the area under the diaphragm would be the test of choice. But again, even this doesn’t rule out surgical disease as free air may be absent on plain films in ⅓ to ½ of patients who have already perfed.
Jeff: Next we have everybody’s favorite, the ultrasound. Because of it’s low cost and ease of use, bedside ultrasound is gaining traction. And we’ve cited this and other similar studies in other issues, this is a skill emergency medicine physicians must have in this day and age and it’s a skill they can learn quickly.
Nachi: Ultrasound can visualize most solid organs, but it is best suited for the Right upper quadrant and pelvis. In the RUQ, we are looking for wall thickening, pericholecystic fluid, ductal dilatation, and sonographic murphys sign.
Jeff: In the pelvis, there is a role for both transabdominal and transvaginal to rule out ectopic and potentially rule in intrauterine pregnancy. I know the thought of performing your own transvaginal ultrasound may sound crazy to some, but we both trained in places where ED TVUS was the norm and certainly wasn’t that hard to learn.
Nachi: Ah, the good old days of residency. I’m certainly grateful for the US tech where I am now though! Next up we have CT. CT scans are ordered in just under 30% of patients with abdominal pain.
Jeff: It’s worth noting, that while many used to scan with triple contrast - oral, rectal and IV, recent literature has shown that IV contrast alone is adequate for the diagnosis of most surgical conditions, including appendicitis.
Nachi: If you’re still working in a shop that scans for RLQ pain with oral or rectal contrast, definitely check out the 2018 american college of radiology appropriateness criteria that states that IV contrast is generally appropriate for assessing the RL.
Jeff: And while we are on the topic of contrast, let’s dive a bit deeper into the, perhaps myth, that contrast leads to contrast induced nephropathy.
Nachi: This is another really important point. Current data show that being ill enough to be admitted to the hospital is a risk factor for acute kidney injury and that IV contrast for CT does not add to that risk. In 2015, the american college of radiology noted in their manual on contrast media that the concern for the development of contrast induced nephropathy is not an absolute contraindication for using IV contrast. IV contrast may be necessary regardless of the risk of nephrotoxicity in certain clinical situations.
Jeff: Ok, so contrast induced nephropathy may be real, but more studies and a definitive statement are still needed. Regardless, if the patient is sick and they need the scan with contrast, don’t hold back.
Nachi: I think that’s a fair take home. As another note about the elderly, CT should be almost routine in the elderly patient with acute abdominal pain as it improves accuracy, optimizes appropriate hospitalization, and boosts ED management decision making confidence for this patient group.
Jeff: If they are over 65, make sure you chart very carefully why they don’t need a scan.
Nachi: Speaking of not needing a scan, two quick caveats on CT before moving to MRI. Unstable patients do not belong in a radiology suite - they belong in the ED resus bay to be resuscitated first. Prompt surgical consultation and bedside ultrasound if indicated are both a must in unstable patients.
Jeff: The second caveat is on the other end of the spectrum - not all CT scanning is created equally - the interpretation depends on the scanner, the quality of the scan, and the experience and training of the reading radiologist. In one study, nearly 13% of abdominal CT scans may initially be misread.
Nachi: So if you’re concerned, consider consultation or an extended ED observation to monitor for any changes in the patient’s status.
Jeff: Next up is MRI - MRI has an ever expanding role in the ED. The accuracy of MRI to diagnose appendicitis is very similar to CT, so consider it in all pregnant patients, though ultrasound is still considered first line.
Nachi: And finally let’s touch upon the ekg and ACS. In patients over 40 with upper abdominal pain, an EKG and troponin should always be considered.
Jeff: Don’t be reassured by a response to a GI cocktail either - this does not exclude myocardial ischemia.
Nachi: Next, let’s talk the role of analgesia in treating the undifferentiated abdominal pain patient.
Jeff: While there was formerly a concern of ‘masking the pain’ with opiates, the evidence says otherwise. Pain medicine may even aid in the diagnosis, so definitely don’t withhold it in the setting of acute abdominal pain.
Nachi: Wait I get that masking the pain is no longer considered a concern, but how would it aid in the diagnosis?
Jeff: Good question. Analgesics might facilitate the gathering of history and allow a more complete physical exam by relaxing the abdominal musculature.
Nachi: Ahh that makes sense. So certainly treat pain! Both morphine at 0.1 mg/kg and fentanyl at 1 mic/kg are appropriate analgesics for acute abdominal pain. In those that are a difficult stick, a recent study showed that 2 micrograms/kg of fentanyl via a nebulizer was a safe alternative. Remember, fentanyl is quick on, quick off, which may make it desirable in certain situations. It actually has the shortest time of onset of any opioid. It’s also safer in patients with a “marginal” blood pressure.
Jeff: And just like the GI cocktail - response to opiate analgesics does not exclude serious pathology. These patients need serial exams and likely labs and imaging if their pain is so severe.
Nachi: Few things are more important prior to discharge of an abdominal pain patient than documenting repeat exams and a PO trial.
Jeff: True. You should also consider haloperidol for patients with gastroparesis and cannabinoid hyperemesis as a growing body of literature supports its use in such settings. Check out the August 2018 EMP or EMplify for more details if you’re curious.
Nachi: The last analgesic to discuss is our good friend ketamine. Low dose ketamine at 0.3 mg/kg over 15 minutes is gaining traction as the analgesic of choice in many ED’s.
Jeff: The key there, is that it must be given over 15 minutes. Ketamine has a great safety profile, but you make it so much safer and a much better experience if you give it slowly.
Nachi: Before we get to disposition, let’s talk controversies and cutting edge - and there is just one this month - and that’s the use of the Alvarado score.
Jeff: In the Alvarado score, you get two points for RLQ tenderness and 2 points for a leukocytosis over 10,000. You get an additional point for all of the following; rebound, temp over 99.1, migration of pain to the RLQ, anorexia, n/v, and a left shift. The max score is therefore 10. A score of 3 or less make appendicitis unlikely, 4-6 warrants CT imaging, and 7 or more a surgical consultation.
Nachi: A 2007 study suggests that using the Alvarado score along with bedside ultrasound might allow for rapid and inexpensive diagnosis of appendicitis.
Jeff: I don’t think we should change practice based on this just yet, but more ultrasound diagnosis may be on the horizon. If you want to start using the Alvarado score in your practice, MDcalc has a great easy to use calculator.
Nachi: Let’s get to the final section. Disposition!
Jeff: As we mentioned at the beginning of this episode, the diagnosis is less important than proper disposition. For patients with suspected ruptured AAA, torsion, or mesenteric ischemia - the disposition is easy - they need immediate surgical consultation and likely operative intervention.
Nachi: For others, use the tools we outlined above - ct, us, labs, etc, to help support your decision. Keep in mind, that serial exams are a great tool and of little expense - so make sure to lay your hands on the patient's abdomen frequently, especially when the diagnosis is unclear.
Jeff: For those that look well after a work up, with no clear diagnosis, it may be reasonable to discharge them home with prompt follow up, assuming prompt follow up is plausible. The key here is that these patients need good discharge instructions. Check out figure 2 on page 20 for a sample discharge template.
Nachi: But if the patient is still uncomfortable, even after a thorough workup, there may be a role for ED observation units. In one study of 220 patients admitted for to ED obs units for serial exams, 39% eventually underwent surgery with only 5% having negative laparotomies.
Jeff: This month’s issue wraps up with some super important time and cost effective strategies, so let’s see if we can quickly breeze through some of the most important points before closing out this episode.
Nachi: First - limit your abdominal x-rays as they offer limited value and are rarely helpful except in the setting of perforation, when an early upright chest film should be used liberally.
Jeff: Next - limit electrolyte testing especially in young adults with nausea, vomiting and diarrhea. In those 18 to 60, clinically significant electrolyte abnormalities occur in only 1% of those with gastro.
Nachi: With respect to urine testing, urine cultures are rarely indicated for uncomplicated cystitis in young women. Along similar lines, don’t anchor on the diagnosis of UTI as other lower abdominal conditions often lead to abnomal urine studies.
Jeff: In your alcoholic patients, although all should be approached with an abundance of caution, limit testing to repeat abdominal exams in your non-toxic appearing patient who is already tolerating PO.
Nachi: For those with suspected renal colic, especially those with a history of renal colic, limit CT use and instead consider ultrasound to look for hydro. This approach is endorsed by ACEPs choosing wisely campaign.
Jeff: But as a reminder, this is for low risk patients only. Anyone with signs of infection should also undergo CT imaging.
Nachi: And lastly - consider incorporating bedside US into your routine. The US is fast and accurate and compares similarly to radiology, especially in the context of detecting acute cholecystitis.
Jeff: Alright, so that wraps up the new material for this episode, let’s close out with some key points and clinical pearls.
Nachi: So that wraps up Episode 29!
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Nachi: And last reminder here -The clinical Decision Making in Emergency Medicine Conference is just around the corner and spots are quickly filling up. Don’t miss out on this great opportunity and register today.
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18. Gardner CS, Jaffe TA, Nelson RC. Impact of CT in elderly patients presenting to the emergency department with acute abdominal pain. Abdom Imaging. 2015;40(7):2877-2882. (Retrospective study; 464 patients aged ≥ 80 years)
38. Kereshi B, Lee KS, Siewert B, et al. Clinical utility of magnetic resonance imaging in the evaluation of pregnant females with suspected acute appendicitis. Abdom Radiol (NY). 2018;43(6):1446-1455. (Retrospective study; 212 MRI examinations)
41. Lewis KD, Takenaka KY, Luber SD. Acute abdominal pain in the bariatric surgery patient. Emerg Med Clin North Am. 2016;34(2):387-407. (Review)
57. Wagner JM, McKinney WP, Carpenter JL. Does this patient have appendicitis? JAMA. 1996;276(19):1589-1594. (Review)
67. Magidson PD, Martinez JP. Abdominal pain in the geriatric patient. Emerg Med Clin North Am. 2016;34(3):559-574. (Review)
83. Macaluso CR, McNamara RM. Evaluation and management of acute abdominal pain in the emergency department. Int J Gen Med. 2012;5:789-797. (Review)
94. Bass JB, Couperus KS, Pfaff JL, et al. A pair of testicular torsion medicolegal cases with caveats: the ball’s in your court. Clin Pract Cases Emerg Med. 2018;2(4):283-285. (Case studies; 2 patients)
106. Kestler A, Kendall J. Emergency ultrasound in first-trimester pregnancy. In: Connolly J, Dean A, Hoffman B, et al, eds. Emergency Point-of-Care Ultrasound. 2nd edition. Oxford UK: John Wiley and Sons; 2017. (Textbook)
Drs. Nachi Gupta and Jeff Nusbaum are practicing emergency physicians in two busy EDs in the US. Join Jeff, a former firefighter, and Nachi, a former mathematician, as they take you through the June 2019 issue of Emergency Medicine Practice: Assessing Abdominal Pain in Adults: A Rational, Cost-Effective, and Evidence-Based Strategy.
Get quick-hit summaries of hot topics in emergency medicine. EMplify summarizes evidence-based reviews in a monthly podcast. Highlights of the latest research published in EB Medicine's peer-reviewed journals educate and arm you for life in the ED.
Why to Use
Acute appendicitis is a common surgical emergency in the United States. Diagnostic accuracy for appendicitis is increased with the use of CT scanning; however, there are risks and disadvantages associated with CT scans, including radiation exposure, contrast-related complications, and cost. The Alvarado score is a well-established and widely used clinical decision tool that may help reduce the need for CT scans in diagnosing appendicitis.
When to Use
The Alvarado score can be used for patients with suspected acute appendicitis (typically, patients presenting with right lower quadrant pain).
Abbreviation: CT, computed tomography.
Ayomide Loye, MD
Xiao Chi Zhang, MD, MS
Clinicians should use clinical judgment in nonclassic presentations of appendicitis.
The Alvarado score was initially described in 1986 by Dr. Alfredo Alvarado in a retrospective study at a single center in Philadelphia. In 305 patients aged4 to 80 years, 8 predictive factors were identified to stratify the risk of acute appendicitis. Increasing scores were found to correlate with increasing risk for appendicitis, as determined by final surgical pathology.
In 2007, McKay et al studied a retrospective cohort of 150 patients (aged ≥ 7 years) presenting with abdominal pain, with the aim of stratifying risk specifically for the use of computed tomography (CT) scanning for diagnosis. They found 35.6% sensitivity for appendicitis based on equivocal Alvarado scores (defined as scores of 4-6) compared with 90.4% sensitivity based on CT scan in this group. They concluded that patients with equivocal scores would benefit from CT scanning.
Similarly, Coleman et al (2018) conducted a retrospective review in which the Alvarado score was applied to a cohort of 492 patients (median age = 33 years), and found that 20% of the patients were in either the high-risk group (defined as scores ≥ 9 in men or a score of 10 in women) or the low-risk group (scores ≤ 1 in men and ≤ 2 in women). These patients spent a cumulative total of > 170 hours awaiting CT scanning that was ultimately unnecessary. The authors found that scores of 0 or 1 had 0% incidence of acute appendicitis and that 100% of men with a score ≥ 9 and 100% of women with a score of 10 had acute appendicitis confirmed on surgical pathology.
Pogorelić et al (2015) prospectively studied 311 pediatric patients and applied both the Alvarado score and the pediatric appendicitis score (Samuel 2002). Receiver operating characteristic analysis showed similar accuracy between the scores, with area under the receiver operating characteristics of 0.74 (95% confidence interval, 0.66-0.82) for the Alvarado score and 0.73 (95% confidence interval, 0.65-0.81) for the pediatric appendicitis score. The authors concluded that the scores may be useful in emergency settings, but neither score is superior to the clinical gestalt of a pediatric surgeon.
Alfredo Alvarado, MD
Why to Use
Blood pressure and heart rate, when used individually, fail to predict accurately the severity of hypovolemia and shock in major trauma. Massive transfusion of blood products can be associated with significant risk when initiated on the wrong patient. Identifying patients who are likely to require massive transfusion can be difficult, and objective measures such as the shock index can help. The shock index has also been shown to be more sensitive than the ABC (assessment of blood consumption) score for massive transfusion (Schroll 2018).
When to Use
Clinicians should consider using the shock index in the following scenarios:
The shock index has been found to be as sensitive as the SIRS criteria to identify patients at risk for sepsis (Berger 2013). However, a large randomized controlled trial showed that use of the shock index to guide fluid resuscitation in sepsis did not demonstrate an improvement in mortality (Yearly 2014).
The accuracy of the shock index for identifying trauma patients in need of massive blood transfusion has not yet been prospectively investigated.
Abbreviation: SIRS, systemic inflammatory response syndrome.
Kamal Medlej, MD
The shock index was first proposed in the literature in 1967 by Allgöwer and Burri as a measure of shock severity. More recently, the shock index has been studied futher with modern protocols.
In a large retrospective study by Mutschler et al (2013), 21,853 patients were identified in a trauma registry. Each patient’s shock index value was calculated based on vital signs taken on arrival at the emergency department. The degree of shock was found to correlate with increasing shock index values. The need for blood products, fluids, and vasopressors was also found to increase with higher shock index values.
A retrospective study by Cannon et al (2009), performed at a single Level I trauma center, identified 2445 patients admitted over a 5-year period. Patients with a shock index value > 0.9 were found to have a significantly higher mortality rate (15.9%) when compared with patients with a normal shock index (6.3%)
In a retrospective registry study by Vandromme et al (2011), the authors identified 8111 patients with blunt trauma who were admitted at a single Level I trauma center over an 8-year period. The shock index value for each patient was calculated from recorded prehospital vital signs, and patients with a shock index value > 0.9 were found to have a 1.6-fold higher risk for massive transfusion.
In a retrospective study of 542 patients who underwent emergency intubation, Heffner et al (2013) identified a pre-intubation shock index value ≥ 0.9 to be independently associated with peri-intubation cardiac arrest.
A retrospective study of 2524 patients at a single center who were screened for severe sepsis found that a shock index value ≥ 0.7 performed as well as the SIRS (systemic inflammatory response syndrome) criteria in negative predictive value and was the most sensitive screening tool for hyperlactatemia and 28-day mortality (Berger 2013).
Of note, in the ProCESS (Protocolized Care for Early Septic Shock) trial (a large, multicenter prospective randomized controlled trial that enrolled 1341 patients), the investigators compared 3 different protocols for resuscitation of septic patients, including a protocol that used a shock index value ≥ 0.8 as a fluid resuscitation goal; the study found no significant difference in mortality between the 3 intervention groups (Yearly 2014).
Manuel Mutschler, MD
Stephen Colucciello, MD, FACEP
Todd Taylor, MD; Nadia Maria Shaukat, MD, RDMS, FACEP
June 1, 2019
June 30, 2022
4 AMA PRA Category 1 Credits™, 4 ACEP Category I Credits, 4 AAFP Prescribed Credits, 4 AOA Category 2-A or 2-B Credits.
Date of Original Release: June 1, 2019. Date of most recent review: May 10, 2019. Termination date: June 1, 2022.
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