Human study shows that inflammation in the esophagus (swallowing tube) and stomach is common and occurs more frequently in Huntington's disease (HD) as it progresses. Study also shows that individuals often do not complain. Lower GI function has not been investigated in individuals with HD, but if mouse models of HD are predictive, we can expect problems there too. But the biggest contributor to gut distress in HD is likely due to medication side effects, less intake of water and more sedentary lifestyle as the disease progresses.
Upper GI problems: In a study published in 2009 [Andrich JE 2009] on 68 individuals with HD that underwent upper GI endoscopy (or a direct look through a tube inserted into esophagus and stomach), investigators found that 32% had esophagitis (inflammation of the esophagus), and an almost equal number had gastritis (inflammation of the stomach) with many of these individuals having inflammation in both. Though some of these individuals had complained of discomfort, most had not. They also found that UGI inflammation appears to occur more often with advanced disease. Though the authors did not show that inflammation was due to acid reflux (as it is in non-HD patients), they suggest that preventative therapy that blocks acid release should be considered for individuals with HD who don't, or can't complain.
The authors have only theories why these abnormalities occur. Further it is unclear if, or how the swallowing problems of HD might contribute to UGI inflammation.
Lower GI problems: No human study information is available. However, studies done in the R62 mouse model [van der Burg JM 2011] show different abnormalities:
Gut motility is impaired: Gastrointestinal (GI) nerves and nerve chemicals associated with gut motility are not normal. This suggests that there is impairment in how food contents are moved down the GI system in a coordinated manner. Irritable bowel syndrome is another condition where there are abnormalities in GI nerve function which results in similar lack of coordination of moving food contents through the bowel. This often results in abdominal bloating, constipation and diarrhea. Study in the R62 mice showed a longer transit time, or it took longer for food to travel through the gut than in control mice.
Absorption of nutrients is impaired: Villi, the cells in the GI tract active in absorbing food and water are thinned. These abnormalities result in poor absorption of nutrients and water, as was shown in this study, causing malnutrition and diarrhea. These combined abnormalities contribute to, but don't initiate weight loss in these mice. In an earlier study [Bushara KO 2004] investigators found the presence of antigliadin antibodies, a blood test that is done usually for celiac sprue. This is a disease caused by glutin (wheat protein) sensitivity that also causes GI distress, malabsorption and diarrhea. This suggests there may be an inflammatory component contributing to GI distress in individuals with Huntington's disease.
Medication and environmental side effects: Probably the most important contributors to GI difficulty in individuals with HD are side effects of the many different medications to control symptoms of HD. Each drug may be associated with stomach upset, diarrhea or constipation, all of which can vary from individual to individual.
As disease progresses to later stages, mobility is impaired, and lesser physical activity further impairs gut motility. Water intake may be limited as swallowing problems increase, and cognitive and communication abilities worsen.
- Though there is no human evidence to support this, it may be worth getting an antigliadin blood test for celiac sprue and making gluten free diet changes --- particularly if there is diarrhea. However be aware that a gluten free diet can take several months before clinical benefit is seen.
- Medication that decreases stomach acid like Prilosec (omeprazole) is probably important in those with later stage disease even in the individual without symptom complaints.
- If possible identify the source of GI distress. If not apparent, you should consult your medical provider. Remember that individuals with HD may have trouble sensing and cognitively interpreting the source of pain or body discomfort. In such situations, anxiety and/or agitation may be the presenting symptoms.
- Remove, decrease dose, or change offending medications to one associated with less GI distress. SSRI drugs (like Zoloft® and Prozac®, etc.) and NSRI drugs (like Effexor®) are more often associated with looser stools, while antipsychotic drugs, some more than others, are more often associated with constipation [De Hert M 2011]. Mood stabilizer drugs (like Tegretol®, Depakote®) commonly cause constipation. Narcotics are the most common drugs to cause constipation. When a new drug is prescribed, ask the doctor about potential GI side effects.
- Change the diet: Increase water intake, and if constipated add fiber and fruit products in foods.
- Increase physical activity.
- Add medications to treat constipation or diarrhea. If a particular medication doesn't work, increase the dosage or try another.
Andrich JE, Wobben M, Klotz P, Goetze O, Saft C. Upper gastrointestinal findings in Huntington's disease: patients suffer but do not complain. J Neural Transm (Vienna). 2009 Dec;116(12):1607-11. doi: 10.1007/s00702-009-0310-1. Epub 2009 Sep 22. PubMed abstract
van der Burg JM, Winqvist A, Aziz NA, Maat-Schieman ML, Roos RA, Bates GP, Brundin P, Björkqvist M, Wierup N. Gastrointestinal dysfunction contributes to weight loss in Huntington's disease mice. Neurobiol Dis. 2011 Oct;44(1):1-8. doi: 10.1016/j.nbd.2011.05.006. Epub 2011 May 23. PubMed abstract
Bushara KO, Nance M, Gomez CM. Antigliadin antibodies in Huntington's disease. Neurology. 2004 Jan 13;62(1):132-3. PubMed abstract
De Hert M, Hudyana H, Dockx L, Bernagie C, Sweers K, Tack J, Leucht S, Peuskens J. Second-generation antipsychotics and constipation: a review of the literature. Eur Psychiatry. 2011 Jan;26(1):34-44. doi: 10.1016/j.eurpsy.2010.03.003. Epub 2010 Jun 9. PubMed abstract