Chronic Diarrhea - Diagnostic Evaluation

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.

New additions to Diagnostic and Statistical Manual of Mental Disorders (DSM-5)

From TIME:

Doctors use the the Diagnostic and Statistical Manual of Mental Disorders (DSM)'s definitions to diagnose more 300 other conditions. Insurance companies use it to justify reimbursements; without a DSM code, mental-health patients and doctors usually don't get paid. DSM-5 is already so famous that it has its own website: http://dsm5.org

On Dec. 1, the American Psychiatric Association approved the fifth edition of the DSM which took 13 years and 1,500 mental-health experts to complete. They tried to approach mental disorders less as discrete illnesses, like leukemia, and more as problems on a continuum, like hypertension.

Here are a few of the new additions in DSM-5:

- Hoarding is included as a diagnosis, meaning those who can't get rid of ephemera can now seek reimbursement for therapy

- Binge eating was in the appendix for more than a decade, but now it's an official diagnosis

- Bereavement. The previous DSM said those in mourning don't necessarily qualify for depression therapy or medication. DSM-5 eliminates that exclusion.

- Excoriation, or skin picking, should be considered a mental illness according to DSM-5

References:

Redefining Mental Illness. TIME, 2012.

Glycated hemoglobin as a diagnostic test for diabetes predicts mortality more accurately than fasting glucose

Fasting glucose is the standard measure used to diagnose diabetes in the United States. Recently, glycated hemoglobin was also recommended for this purpose.

The glycated hemoglobin value at baseline was associated with newly diagnosed diabetes and cardiovascular outcomes.

For glycated hemoglobin, values of less than 5.0%, 5.0-5.5%, 5.5-6.0%, 6.0-6.5%, and 6.5% or greater, the hazard ratios for diagnosed diabetes were 0.52, 1.00, 1.86, 4.48, and 16.47, respectively.

For coronary heart disease, the hazard ratios were 0.96, 1.00, 1.23, 1.78, and 1.95, respectively. The hazard ratios for stroke were similar.

In contrast, glycated hemoglobin and death from any cause were found to have a J-shaped association curve.

The association between the fasting glucose levels and the risk of cardiovascular disease or death from any cause was not significant.

In this community-based population of nondiabetic adults, glycated hemoglobin was associated with a risk of diabetes and more strongly associated with risks of cardiovascular disease and death from any cause as compared with fasting glucose. These data add to the evidence supporting the use of glycated hemoglobin as a diagnostic test for diabetes.

References:

Glycated Hemoglobin, Diabetes, and Cardiovascular Risk in Nondiabetic Adults. NEJM, 2010.

Image source: OpenClipArt.org, public domain.