While Crohn disease primarily affects the gastrointestinal tract, it also has consequences for the brain. An inflammatory bowel disease, Crohn disease may have mental effects due to its troublesome symptoms that include abdominal pain, diarrhea that can be bloody, fatigue and weight loss. It is also a chronic condition, however, that has been associated with an increased risk of stroke and psychological problems, as well as physical changes to the brain.
Increased Stroke Risk
Strokes have been reported in people with Crohn disease. A study published in the March 2014 "European Journal of Internal Medicine" noted that individuals with Crohn disease show an increased risk of mini-strokes compared to those without the disease. Furthermore, a study in the November 2013 issue of "BMC Neurology" reported increased subarachnoid hemorrhaging, a major cause of stroke, in hospitalized individuals with Crohn disease. Studies have also found that the increased stroke risk may be higher in younger people with Crohn disease compared to older individuals with the disease, as reported in a study published in the August 2010 issue of "Inflammatory Bowel Diseases."
People with Crohn disease exhibit increased anxiety and depression compared to those without the disease, according to a September 2014 report published in "PLoS One." Mood disorders, emotional problems and the possible role of chronic stress have also been associated with the disease, but an April 2014 study report in the "World Journal of Gastroenterology" notes the uncertainty in whether these psychological problems are a result of the poor quality of life produced by Crohn disease or connected to the origin of the disease itself.
Structural Brain Changes
Changes in the structure of the brain have been reported in patients with Crohn disease as well. Compared to healthy patients, as described in the January 2013 issue of "Neurogastroenterology & Motility," patients with Crohn disease show reductions in gray matter volume in many regions of the brain. Some of these regions are responsible for pain and emotional and cognitive processes. The study also noted that these reductions in brain volumes increased with a longer disease duration.
Other Brain Effects
Peripheral neuropathy is characterized by damage to the peripheral nerves that connect the brain to the rest of the body, resulting in symptoms like pain, tingling and weakness in the arms and legs, as well as general muscle weakness, dizziness and blurred vision. Though neuropathy has been previously associated with Crohn disease, a review in the February 2014 issue of the "World Journal of Gastroenterology" points out that this finding may be controversial, with some studies finding a very low prevalence in individuals with Crohn disease.