Chronic Diarrhea - Diagnostic Evaluation

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Chronic diarrhea is defined as a decrease in stool consistency (loose BM) for more than 4 weeks (Am Fam Physician, 2011).

It can be divided into 3 categories:

- watery
- fatty (malabsorption)
- inflammatory

Watery diarrhea

Watery diarrhea may be subdivided into:

- osmotic
- secretory
- functional, e.g. IBS

Watery diarrhea includes irritable bowel syndrome (IBS), which is the most common cause of functional diarrhea. Another example of watery diarrhea is microscopic colitis, which is a secretory diarrhea affecting older persons.

Laxative-induced diarrhea is often osmotic.

Malabsorptive diarrhea

Malabsorptive diarrhea is characterized by excess gas, steatorrhea, or weight loss. Giardiasis is a classic infectious example of malabsorptive diarrhea.

Celiac disease (gluten-sensitive enteropathy) is also malabsorptive, and typically results in weight loss and iron deficiency anemia.

Inflammatory diarrhea

Inflammatory diarrhea, such as ulcerative colitis (UC) or Crohn disease, is characterized by blood and pus in the stool and an elevated fecal calprotectin level.

Invasive bacteria and parasites also produce inflammation. Infections caused by Clostridium difficile (C. diff.) subsequent to antibiotic use have become increasingly common and virulent.


Image source: Escherichia coli, Wikipedia, public domain.

Not all chronic diarrhea is strictly watery, malabsorptive, or inflammatory, because some categories overlap.

References:

Evaluation of Chronic Diarrhea. Juckett G, Trivedi R. Am Fam Physician. 2011 Nov 15;84(10):1119-1126.
Skin patch vaccine to prevent travelers' diarrhea
Image source: Colon (anatomy), Wikipedia, public domain.

How to evaluate a patient with chronic cough?

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Initial evaluation of chronic cough (defined as more than 8 weeks' duration in adults and 4 weeks in children) should include a chest radiography (CXR) in most adult patients.

Patients who are taking an angiotensin-converting enzyme inhibitor (ACEi) should switch to a medication from another drug class.



Differential diagnosis of cough, a simple mnemonic is GREAT BAD CAT TOM. Click here to enlarge the image: (GERD (reflux), Laryngopharyngeal Reflux (LPR), Rhinitis (both allergic and non-allergic) with post-nasal drip (upper airway cough syndrome), Embolism, e.g. PE in adults, Asthma, TB (tuberculosis), Bronchitis, pneumonia, pertussis, Aspiration, e.g foreign body in children, Drugs, e.g. ACE inhibitor, CF in children, Cardiogenic, e.g. mitral stenosis in adults, Achalasia in adults, Thyroid enlargement, e.g. goiter, "Thoughts" (psychogenic), Other causes, Malignancy, e.g. lung cancer in adults).

The most common causes of chronic cough in adults are:

- upper airway cough syndrome (post-nasal drip)
- asthma
- gastroesophageal reflux disease (GERD)
- any combination of the above

If upper airway cough syndrome is suspected, a trial of a decongestant and an antihistamine is warranted.

The diagnosis of asthma can be confirmed with a clinical response to empiric therapy with inhaled bronchodilators or corticosteroids (spirometry is generally preferred though).

Empiric treatment for gastroesophageal reflux disease (GERD) should be initiated in lieu of testing for patients with chronic cough and reflux symptoms.

Patients should avoid exposure to cough-evoking irritants, such as cigarette smoke.

Further testing may be indicated if the cause of chronic cough is not identified and includes:

- high-resolution computed tomography (CT) of the chest
- referral to a pulmonologist or an allergist

In children, a cough lasting longer than 4 weeks is considered chronic.

The most common causes of chronic cough in children are:

- respiratory tract infections ("bronchitis" and pneumonia)
- asthma
- rhinitis with post-nasal drip
- gastroesophageal reflux disease (GERD)
- aspirated foreign body is relatively rare but must not be missed

Evaluation of children with chronic cough should include chest radiography (CXR) and spirometry (if older than 5 years of age). Skin prick test for environmental allergies can also be indicated.

References:

Evaluation of the patient with chronic cough. Benich Iii JJ, Carek PJ. Am Fam Physician. 2011 Oct 15;84(8):887-92.

Diagnosis of chronic cough in children

"Doctors make mistakes. Can we talk about that?" ED physician Brian Goldman's TED talk

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Dr. Goldman asks if you know your surgeon's "batting average" of operations with good outcomes. He mentions the three words you never want to hear: "Do you remember?" It's a good TED talk:



Every doctor makes mistakes (just like everyone does). But, says Dr. Goldman, medicine's culture of denial (and shame) keeps doctors from ever talking about those mistakes, or using them to learn and improve. Telling stories from his own long practice, he calls on doctors to start talking about being wrong.

Here are some simple steps to avoid medical errors from a patient's perspective (source: CNN):

1. Say: "My name is Mary Smith, my date of birth is October 21, 1965, and I'm here for an appendectomy."
2. Say: "Please check my ID bracelet."
3. Say: "Please look in my chart and tell me what procedure I'm having."
4. Say: "I want to mark up my surgical site with the surgeon present."
5. Be impolite (this particular piece of advice is obviously controversial).

References:

CNN video: Steps to avoid medical errors

The Rise of the ePatient - presentation by Pew Internet Project

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Director Lee Rainie presented at Providence St. Joseph Medical Center in Burbank, California on January 12, 2012 on understanding social networking and online health information seeking:

The Rise of the e-Patient

View more presentations from Pew Research Center's Internet & American Life Project

Link via via e-patients.net

Here is how to facilitate the Rise of the ePhysican who works hand in hand with the ePatient:



References:

Social media in medicine: How to be a Twitter superstar and help your patients and your practice

Blogging is good for you - and for most people who read blogs

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From The Economist:

"Academic papers cited by bloggers are far more likely to be downloaded. Blogging economists are regarded more highly than non-bloggers with the same publishing record.

The back-and-forth between bloggers resembles the informal chats, in university hallways and coffee rooms, that have always stimulated economic research, argues Paul Krugman, a Nobel-prize winning economist who blogs at the New York Times. But moving the conversation online means that far more people can take part.

Despite the low barriers to entry, blogs do impose some intellectual standards. Errors of fact or logic are spotted, ridiculed and corrected. Areas of disagreement are highlighted and sometimes even narrowed."

Similar dynamics are in work on many medical blogs authored by physicians.

WIN-WIN, as the author of the blog "The Happy Hospitalist" likes to say.

References:

Economics blogs. A less dismal debate. The Economist, 01/2011.