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Key Feature 6: In a young person with chronic or recurrent diarrhea, with no red flag symptoms or signs, use established clinical criteria to make a positive diagnosis of irritable bowel syndrome (do not overinvestigate). Skill: Clinical Reasoning, Selectivity Phase: Diagnosis Key Feature 7: In patients with chronic or recurrent diarrhea, look for both gastro-intestinal and non-gastro-intestinal symptoms and signs suggestive of specific diseases (ex: inflammatory bowel disease, malabsorption syndromes, and compromised immune system). Skill: Clinical Reasoning Phase: History, Physical According to the UpToDate article, "Clinical manifestations and diagnosis of irritable bowel syndrome in adults" (2018), "Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract characterized by chronic abdominal pain and altered bowel habits." The standard diagnostic criteria for irritable bowel syndrome (IBS) are the Rome IV criteria. A symptom cluster qualifies for a diagnosis of IBS according to these criteria when there is recurrent abdominal pain, on average, at least one day per week in the last three months, associated with two or more of the following criteria:
Note that for a diagnosis of IBS, abdominal pain must be part of the symptom cluster. Abdominal pain, pain with defecation, and constipation and/or diarrhea - all symptoms associated with IBS - by themselves have their own differential diagnosis, and when a clinician is first assessing a patient with such symptoms, they must consider the full diagnostic differential so as not to miss a more ominous disease process. In a patient with suspected IBS based on history and fulfilment of the Rome IV IBS criteria, what are the red flags to look for to decide whether further investigations are warranted before confidently ascribing symptoms to IBS alone? The UpToDate article cited above provides an approach to the initial evaluation of a patient with a suspected diagnosis of IBS. It includes the following considerations:
So in conclusion, if a patient has suspected IBS based on meeting the Rome IV criteria, and if they do not have any red flag features as listed above, then they warrant investigation with a CBC only. If they also have diarrhea (note that a subset of patients with IBS only have constipation without diarrhea), then they also deserve a CRP (or fecal calprotectin) to rule out an inflammatory process, as well as serologic testing for celiac disease. In keeping with general population guidelines, their screening for colorectal cancer should also be UpToDate. If all of the applicable testing is unremarkable, then one can feel fairly confident that the patient truly has a diagnosis of IBS without resorting to exhaustive testing to rule out a multiplicity of possible but improbable differential diagnoses. In my experience, it tends to be patients who request more testing because they are worried there is more worrisome disease going on in their body (which is not surprising since their symptoms can feel very strong and alarming). But further testing just for patient reassurance is not only unnecessary, it can actually do harm. Some of the ways this may manifest is by leading to false positives (positive test results suggestive of disease when disease is not actually present), or by causing more indirect harm by reinforcing the idea that further testing is required in order to be reassured, which perpetuates a cycle of wanting more and more testing for reassurance, and promotes more anxiety and distress. On a population scale, this also leads to significantly increased health care costs without benefit in patient health or quality of life. One of the benefits of medicine today is that we are constantly refining our understanding of when tests are and are not indicated based on studies looking at the outcomes of investigations that are done - one of the reasons that screening guideline recommendations are always changing. More testing is not always a good thing.  *The physical examination of a patient with chronic or recurrent diarrhea is important as there are clues to look for that can help increase or decrease the likelihood of various diseases. It is also useful in classifying the severity of the diarrhea by looking for signs of dehydration. According to the UpToDate article, "Approach to the adult with chronic diarrhea in resource-rich settings" (2018), the physical examination of a patient with chronic diarrhea should include assessment for:
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Key Feature 5: Pursue investigation, in a timely manner, of elderly with unexplained diarrhea, as they are more likely to have pathology.
Skill: Clinical Reasoning, Selectivity Phase: Hypothesis generation, Investigation When someone comes in with a complaint of acute diarrhea, it's usually a viral gastroenteritis. So we don't necessarily do any tests right away if the patient looks well and doesn't have risk factors. That being said, if a patient appears unwell or with risk factors for more serious underlying disease, doing some investigations sooner rather than later is warranted. What are the indications for performing investigations in the setting of acute diarrhea? If a patient appears dehydrated then ordering a set of electrolytes and a creatinine would be useful to look for complications of the diarrhea, regardless of the etiology. A CBCd may be ordered as a nonspecific marker of disease severity if this is something that may be monitored, say in a patient who is being admitted. Indications for first-line microbiological testing to look for an underlying infectious pathogen for the diarrhea include:
Imaging would seldom be indicated in the setting of acute diarrhea, but there are 2 reasons for which you may consider getting an imaging study:
*Note that if there is bloody diarrhea, the patient is at risk of having EHEC (Enterohemorrhagic E. coli), and further tests are indicated right off the bat that include: stool culture for EHEC and shiga toxin, and fecal leukocytes or fecal lactoferrin (not available everywhere). Furthermore, if there are ever any pathogens that you are particularly suspicious of, it is a good idea to check with the lab that you are sending the sample to, to see if they test the stool for the bacteria you are suspecting, and it doesn't hurt to write this down on the requisition form as well, as certain organisms are tested for with special techniques, which the lab may not do by default. Key Feature 4: In patients with acute diarrhea, counsel about the timing of return to work/school (re: the likelihood of infectivity).
Skill: Clinical Reasoning Phase: Treatment I must admit, I have not been giving advice to patients with acute diarrhea about preventing the spread of possible infection to others, and I've already been on my pediatric ED rotation for 3 weeks, seeing buttloads of it. At the same time, I haven't really been hearing my attending preceptors do this either. But this seems like such a common sense and important part of the counselling around diarrhea of presumably infectious origin, and it is a standard public health consideration. I took a look at a few UpToDate articles on acute diarrhea and didn't see anything in the body of the information for clinicians. On the patient handouts, however, I found multiple handouts providing advice on preventing the spread of infection. The advice included the following: From the UpToDate patient handout, "Acute diarrhea in adults"
From the UpToDate patient handout, "Acute diarrhea in children"
Just another reason for providing a patient handout! Not to say this is a cop-out either, I definitely plan to provide verbal advice to stay away from public environments while there is ongoing acute diarrhea. But it has been well understood for a long time that patients have information incontinence when it comes to retaining information provided by physicians. In the article, "Patients' memory for medical information" by Roy Kessels as published in the Journal of the Royal Society of Medicine (2003), "Memory for medical information is often poor and inaccurate, especially when the patient is old or anxious. Patients tend to focus on diagnosis-related information and fail to register instructions on treatment. Simple and specific instructions are better recalled than general statements. Patients can be helped to remember medical information by use of explicit categorization techniques. In addition, spoken information should be supported with written or visual material." A handout a day keeps the doctor away. Key Feature 2: In patients with acute diarrhea, use history to establish the possible etiology (ex: infectious contacts, travel, recent antibiotic or other medication use, common eating place for multiple ill patients). Skill: Clinical Reasoning Phase: Hypothesis generation, History Key Feature 3: In patients with acute diarrhea who have had recent hospitalization or recent antibiotic use, look for clostridium difficile. Skill: Clinical Reasoning Phase: Hypothesis generation People's bowels are not their friends. It seems like every other patient who comes in to the family doctor's office or the emergency department falls on one end or the other of the diarrhea-constipation dichotomy. While both can be signs of significant disease, they are often usually benign and respond well to simple treatments. Whenever there is a sudden onset of these symptoms, my role as a primary care physician is to try to figure out the underlying reason so that I can devise an appropriate treatment plan. In this post, I will focus on the patient with acute diarrhea (generally more acutely worrisome than constipation because if severe, it can lead to life-threatening dehydration). My differential diagnosis for acute diarrhea is as follows:
You'll notice at the top of the list of diagnostic possibilities is infection, in three different ways. Acute onset of diarrhea is usually infectious in origin. Looking for clues on history can help to stratify a patient's risk for infection, and includes gathering information on:
*For patients who have taken antibiotics or who have been hospitalized in the last 3 months prior to the onset of diarrhea, they are at increased risk for acquiring Clostridium difficile diarrhea (aka C. diff). It is important to know that some people are asymptomatic carriers of C diff, which makes a stool culture for C diff not helpful and so it is not done by the lab. The ordering physician who suspects C diff diarrhea must instead specify that they wish to perform a C diff assay, which tests for the C diff toxins that are produced when C diff is the reason for the diarrhea. On weird but interesting note, one of the most effective treatments for recurrent C diff is fecal microbial transplantation. See the video below as produced by John Hopkins University School of Medicine for more information about this. By the end of postgraduate training, using a patient-centred approach and appropriate selectivity, a resident, considering the patient’s cultural and gender contexts, will be able to...
Dehydration Key Feature 1: When assessing the acutely ill patient, look for signs and symptoms of dehydration. (ex: look for dehydration in the patient with a debilitating pneumonia). Skill: Clinical Reasoning Phase: Hypothesis generation Key Feature 2: In the dehydrated patient, assess the degree of dehydration using reliable indicators (ex: vital signs) as some patients' hydration status may be more difficult to assess (ex: elderly, very young, pregnant). Skill: Clinical Reasoning Phase: Physical, Investigation Key Feature 3a: In a dehydrated patient: Determine the appropriate volume of fluid for replacement of deficiency and ongoing needs. Skill: Clinical Reasoning Phase: Treatment, Diagnosis Key Feature 3b: In a dehydrated patient: Use the appropriate route (oral if the patient is able; IV when necessary). Skill: Clinical Reasoning Phase: Treatment Key Feature 4: When treating severe dehydration, use objective measures (ex: lab values) to direct ongoing management. Skill: Clinical Reasoning Phase: Investigation, Treatment Key Feature 5: In a dehydrated patient: Treat the precipitating illness concurrently. Skill: Clinical Reasoning Phase: Treatment Key Feature 6: Treat the dehydrated pregnant patient aggressively, as there are additional risks of dehydration in pregnancy. Skill: Clinical Reasoning, Selectivity Phase: Hypothesis generation, Treatment Diarrhea Key Feature 1a: In all patients with diarrhea: Determine hydration status. Skill: Clinical Reasoning Phase: Diagnosis Key Feature 1b: In all patients with diarrhea: Treat dehydration appropriately. Skill: Clinical Reasoning Phase: Treatment Pneumonia Key Feature 2: In a patient with signs and symptoms of pneumonia, do not rule out the diagnosis on the basis of a normal chest X-ray film (ex: consider dehydration, neutropenia, human immunodeficiency virus [HIV] infection). Skill: Clinical Reasoning, Selectivity Phase: Diagnosis, Hypothesis generation Key Feature 3: In a patient with a diagnosis of pneumonia, assess the risks for unusual pathogens (ex: a history of tuberculosis, exposure to birds, travel, HIV infection, aspiration). Skill: Clinical Reasoning Phase: History, Hypothesis generation Today I encountered a 9 year female with congenital muscular dystrophy who was presenting with an acute cough, vomiting, and diarrhea. She looked unwell, and dehydrated, and on lung exam she had decreased breath sounds on one side of her lungs compared to the other. Chest xray revealed a middle lobe pneumonia. What are the signs and symptoms of dehydration? Late signs
Early signs
Evaluating someone's volume status (i.e., whether they are hypovolemic, euvolemic, or hypervolemic) is a clinical assessment; there are no tests that can specifically tell you whether or not someone is dehydrated or fluid-overloaded. It's all about considering various clinical indicators of volume status, and different patient factors can make certain indicators more or less useful. For example, in the very young patient, the degree to which their anterior fontanelle is filled, from bulging to very sunken, can be a very useful indicator of volume status, but this is not useful once the anterior fontanelle is closed, which is usually the case by the age of 2. Whereas in the elderly patient with wrinkled skin, using skin turgor to assess degree of dehydration is pretty well useless. And when it comes to the patient who is pregnant, a high index of suspicion is needed because there are many physiologic adaptations to pregnancy that may mask early signs of dehydration. Furthermore, the ramifications could be as significant as dehydration inducing uterine cramping and preterm labour, or could manifest in long-term complications related to impairments in fetal growth and development; a lower threshold to begin a rehydration regimen can have a significant benefit-to-risk ratio. Vital signs are a useful component of the evaluation of volume status as they are objective (including, in the pregnant patient, fetal heart rate +/- amniotic fluid volume assessment by ultrasound), but by themselves they may not be sufficient enough to determine volume status as abnormal vital signs can be a reflection of much more than volume status. For example, a dehydrated patient could be expected to be tachycardic, but tachycardia can also be caused by fever, or hyperthyroidism, or anxiety, or pain, etc. So the vital signs must be interpreted in the clinical context as well, much as the more subjective indicators of volume status need to be. When a patient is determined to be dehydrated, it's time to get them rehydrated while treating the precipitating cause, which for the above patient case meant to give antibiotic therapy for the pneumonia.* The approach to rehydration will depend on how dehydrated you think the patient is, and is generally clinically assessed as being mild, moderate, or severe. For any degree of degree of dehydration, from mild to severe, rehydration will consist of a replacement phase (to replace fluid debt; normal saline [NS] is always used) followed by maintenance (to replace ongoing losses; type of solution here will depend on context). The approach will also depend on patient factors, such as whether they are a pediatric or adult patient, whether they have comorbidities such as kidney disease or diabetes, whether there are any ongoing sources of fluid loss (ex: diarrhea, vomiting, sweating), and if they have an electrolyte disturbance. Note that most people walking around in the world are maintaining their fluids orally, and in general this is the preferred approach. In the severely dehydrated patient, however, oral replacement just won't suffice, and so intravenous fluid resuscitation is always indicated in this situation. In the moderately dehydrated patient, it is still very important to replace their fluid debt, but the situation is not as critical, at least not yet. If the patient is tolerating oral fluids and is well enough to drink lots of fluid, instead of automatically initiating intravenous fluid replacement, you may wish to consider a trial of oral rehydration first (if it would be feasible given the reason for the dehydration and the patient's ability to compensate). And then, if the patient is tolerating oral fluids, it's always best to try replacing fluid debt orally if the severity of the dehydration is nothing more than mild. It goes without saying (but I'll say it anyway for completion) that anyone who can tolerate oral fluids definitely does not need intravenous replacement (unless ongoing losses are so extreme that the patient just can't keep up). In this latter situation, the patient would be like everyone else who compensates for typical water loss in a day by taking in enough fluid in food and drinks to compensate for fluid lost in urine, stool, perspiration, and insensible losses (from the skin and respiratory tract). Sometimes this would be the only intervention that would be keeping a patient in hospital, and with patients/caregivers who you expect will be reliable to follow-up if things are not improving or worsening, it is a waste of health care resources and is usually less pleasant for the child who could otherwise be more comfortable in their own bed. Generally, patients who are assessed for urgent or emergent medical issues and who are deemed safe to follow-up as an outpatient may be discharged for outpatient management. This is preferred by most patients and healthcare providers, the latter of whom are also familiar with the real possible of secondary nosocomial illness secondary to hospital admission. For the patient with mild to moderate dehydration who is a candidate for oral rehydration therapy, is any fluid okay? Well any fluid is better than no fluid, but some fluids are better than others. In particular, the World Health Organization recommends Oral Rehydration Solution, which is a specific mixture of water, glucose, and salt. Because water follows sodium, if we have sodium in the solution, then as this is taken up by the gastrointestinal tract, more water will also get absorbed. There are also receptors in the gut that take up more sodium when glucose is present (sodium-glucose transport proteins), and so by adding in glucose as well, the uptake of water is even greater. To make your own Oral Rehydration Solution, combine 1L of water with a half of a teaspoon (2.5 mL) of salt and 2 tablespoons (30 mL) of sugar. Alternatively, there are products that can be purchased other-the-counter from pharmacies. For those in whom oral rehydration therapy will not suffice, IV fluids are indicated. Below are my approaches to rehydration in adult and pediatric patients, respectively, when IV fluids are required. Adult
Pediatric
All this talk of fluid replacement is getting me thirsty!  *Note that while this patient presented with x-ray evidence of pneumonia, many dehydrated patients may have a falsely negative chest x-ray early on in the disease process, which may also be the case for patients who are immunocompromised. If suspected clinically and the patient has risk factors for being unable to mount a swift early immune response, consider the need for empiric treatment for suspicion of pneumonia to prevent patient decompensation/deterioration. It's also important to consider risk factors a patient may have for acquisition of unusual pathogens, as may also occur in the patient who is immunocompromised or who has had unusual exposures to animals or other environments through travel. In the elderly or neurologically/cognitively compromised patients, consider their risk of chemical pneumonitis from aspiration. These risk factors matter because they influence choice of antibiotic.
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