Investigating the efficacy of osteopathic manipulative treatment for intractable hiccups: a pilot study

Intractable hiccups is a rare medical condition defined as daily hiccups continuing for more than 30 days and is recognized by the National Organization for Rare Disorders (NORD) and NIH Genetic and Rare Diseases (GARD) Information Center. Hiccups are spasmodic contractions of the respiratory muscles, triggered by activation of the hiccup reflex arc. Intractable hiccups can occur if this arc is chronically or aberrantly activated. The hiccup reflex arc has three components: (1) afferent pathways involving the phrenic, sympathetic, and vagal nerves; (2) central processing centers within the central nervous system; and (3) efferent fibers, including the phrenic nerve, vagal branches, and intercostal nerves. Previously published case reports have reported robust improvements to intractable hiccup disease severity after osteopathic manipulative treatment (OMT) for related areas of somatic dysfunction, with one achieving complete remission. However, no structured studies have evaluated this approach to date.

The objective of this case series is to determine whether one session of OMT can reduce the severity of intractable hiccups.

Five participants aged 18 and older with intractable hiccups were recruited through physician offices, online postings, and flyers placed on and around the Michigan State University (MSU) campus over a 2-year study period. Following eligibility screening, participants recorded their daily hiccup frequency and associated symptoms for 7 days before and after OMT. Each participant received one OMT session after a comprehensive medical history and osteopathic musculoskeletal examination. Identified somatic dysfunctions were treated utilizing appropriate OMT techniques. Muscle energy, counterstrain, and Still Techniques were utilized most frequently. High-velocity, low-amplitude (HVLA) methods were not employed in this study. All treatments were performed by an experienced osteopathic physician at the university-associated osteopathic manipulative medicine (OMM) clinic.

Across the participants, we observed common patterns of somatic dysfunction in the cervical spine (C1 and C5), thoracic regions, and the abdominal diaphragm. After OMT, patients experienced clinically meaningful and statistically significant reductions in hiccup frequency. The average number of daily hiccups decreased from 16.37 to 5.66, representing a 65.4 % reduction after intervention (paired t-test, p=0.018). In addition, three out of the five participants experienced statistically significant reductions in their mean number of daily hiccups after treatment (t-test, p<0.05).

This case series is the first structured investigation into the use of OMT for intractable hiccups. The findings strongly suggest that OMT can be an effective option for reducing the disease burden of intractable hiccups through the treatment of related areas of somatic dysfunction. Our results also support a plausible mechanistic basis for OMT's effectiveness, because somatic dysfunctions were consistently found along the hiccup reflex arc. Finally, the study raises the possibility that the prevalence of intractable hiccups is underrecognized and may represent a clinical domain in which osteopathic care provides distinct advantages.