Noninvasive ¹³C-Octanoic Acid Breath Test Shows Delayed Gastric Emptying in Patients with Amyotrophic Lateral Sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive loss of motor neurons. However, ALS has been recognized to also involve non-motor systems. Subclinical involvement of the autonomic system in ALS has been described. The recently developed ¹³C-octanoic acid breath test allows the noninvasive measurement of gastric emptying. With this new technique we investigated 18 patients with ALS and 14 healthy volunteers. None of the patients had diabetes mellitus or other disorders known to cause autonomic dysfunction. The participants received a solid standard test meal labeled with ¹³C-octanoic acid. Breath samples were taken at 15-min intervals for 5 h and were analyzed for ¹³CO₂ by isotope selective nondispersive infrared spectrometry. Gastric emptying peak time (t_peak) and emptying half time (t½) were determined. All healthy volunteers displayed normal gastric emptying with a mean emptying t½ of 138 ± 34 (range 68–172) min. Gastric emptying was delayed (t½ > 160 min) in 15 of 18 patients with ALS. Emptying t½ in ALS patients was 218 ± 48 (range 126–278) min (p < 0.001). These results are compatible with autonomic involvement in patients with ALS, causing delayed gastric emptying of solids and encouraging the theory that ALS is a multisystem disease rather than a disease of the motor neurons only.

Altered Metabolic Homeostasis in Amyotrophic Lateral Sclerosis: Mechanisms of Energy Imbalance and Contribution to Disease Progression

“…Furthermore, the TDP-43 mouse model of ALS exhibits intestinal dysfunction characterized by a progressively thinned colon, swollen small intestine, reduced food intake, and increased TDP-43 accumulation in the myenteric nerve plexus, which contributes to death independent of muscular weakness [91,92]. In addition to animal models of ALS manifesting abnormalities of the gut, autonomic dysfunction has been described in ALS patients [44], with reports of subclinical gastrointestinal motor dysfunction [43], delayed colonic transit times [93], delayed gastric emptying [94], and an increased prevalence of constipation [95]. Furthermore, a study of percutaneously fed individuals with ALS found that 7 of 10 experienced weight loss that was unexplained by dysphagia, hypermetabolism, or inadequate diet [96].…”

Dumping syndrome following nissen fundoplication in an adult patient diagnosed by continuous online 13C/12C monitoring of 13C-Octanoic acid breath test "a case report"

“…The use of breath tests with 13 C-Octanoic acid for the detection of rapid gastric emptying has been reported [12,13]. The use of BreathID ® continuous online 13 C-Octanoic acid breath test system for the detection of the relationship between hypoglycemia and gastric emptying abnormalities in diabetic patients treated with subcutaneous insulin has been already published as well [14].…”

Survey of current enteral nutrition practices in treatment of amyotrophic lateral sclerosis

“…12,13 Whether this is an effect of malnutrition on the gastrointestinal tract or whether this is a symptom of gastrointestinal dysfunction due to ALS itself is unclear, and would be an important avenue for investigation. 14–16 The frequency of weight loss after institution of EN has not been reported in prior case series and clinical trials involving feeding tube placement in ALS. 7 This may suggest that our survey data are less reliable than case series and clinical trial data.…”