Conventional manometry presents significant challenges, especially in assessment of pharyngeal swallowing, because of the asymmetry and deglutitive movements of oropharyngeal structures. It only provides information about intraluminal pressure and thus it is difficult to study functional details of esophageal motility disorders. New technology of solid high resolution impedance manometry (HRIM), with 32 pressure sensors and 6 impedance sensors, is likely to provide better assessment of pharyngeal swallowing as well as more information about esophageal motility disorders. However, the clinical usefulness of application of HRIM in patients with oropharyngeal dysphagia or esophageal dysphagia is not known. We experienced a case of Huntington’s disease presenting with both oropharyngeal and esophageal dysphagia, in which HRIM revealed the mechanism of oropharyngeal dysphagia and provided comprehensive information about esophageal dysphagia.

Conventional manometry presents considerable challenges in evaluation of oropharyngeal dysphagia because of the asymmetry and deglutitive movements of oropharyngeal structures[1]. Introduction of high resolution manometry (HRM), which employs pressure sensors at 1 cm intervals across the entire anatomic region from the oropharynx to the stomach represented a significant improvement in data recording and diagnostic yield, especially in cases of functional dysphagia over conventional manometry[1,2]. However identifying a manometric abnormality does not equate to identifying a disease and thus achalasia and (perhaps) diffuse esophageal spasm are relevant to manometric findings, which have a functional correlate and can cause dysphagia[3]. Most recently, high resolution impedance manometry (HRIM) has been introduced to combine the benefits of HRM and impedance-based bolus transit assessment. Actually patients with normal manometry can have abnormal bolus transit, and patients with abnormal manometry can have normal bolus transit[4]. Koya et al[5] reported that abnormal impedance even in patients with normal manometry may be a sensitive indicator of esophageal functional abnormality as represented by the symptom of dysphagia in these patients.

To our knowledge, little is known with regard to investigation of dysphagia using the HRIM technique. We experienced a case of Huntington’s disease presenting with both oropharyngeal and esophageal dysphagia, in which HRIM revealed the mechanism of oropharyngeal dysphagia, and provided comprehensive information about esophageal dysphagia.

To our knowledge, this report is the first study of Huntington’s disease using HRIM, which indicated the combined oropharyngeal and esophageal dysphagia. The patient had difficulty in initiating swallowing and had retrosternal bolus hold-up. Insidious onset of dysphagia associated with some neurologic symptoms such as chorea and dysarthria suggested oropharyngeal dysphagia from a neurologic basis. A video fluoroscopic swallowing study provided the diagnosis of oropharyngeal dysphagia which resulted from a lack of coordination between the oral and pharyngeal stage. Unexpected involuntary movement in the oral cavity induced oropharyngeal incoordination. Oropharyngeal dysphagia in Huntington’s disease results from tachyphagia, or rapid uncontrolled swallowing, secondary to impaired sensory and cognitive function[7]. Furthermore, it is caused by buccolingual chorea resulting in food being transferred impulsively[7]. Respiratory chorea, marked by involuntary respiratory movements, occurs in approximately 40% of patients, and interrupts the normal respiratory-deglutition cycle[8]. Given the anatomical structures involved in vocalization, the HRIM findings using the modified method may reflect the mechanism of oropharyngeal dysphagia in the Huntington’s disease patient. In other words, the modified test may disclose oropharyngeal incoordination related to buccolingual chorea, which cannot be detected even with HRM or HRIM using the usual protocol such as the liquid and viscous swallow test. Further investigation should be carried out to confirm the role of the vocal test in either HRM or HRIM studies for assessing oropharyngeal dysphagia related to chorea.

HRIM results concerning esophageal dysphagia appeared to indicate diffuse esophageal spasm (DES) such as simultaneous contraction associated with > 10% of wet swallows, mean simultaneous contraction amplitude > 30 mmHg, and repetitive contractions. Esophageal dysmotility of the patient, however, can be better classified as an atypical disorder of LES relaxation because there was incomplete relaxation of the LES[9]. The esophageal dysmotility in this case may be an intermediate form between DES and achalasia because a few case reports have suggested a transition from DES to achalasia in some patients[10-12].

Kagel et al[13] reported esophageal dysphagia was relatively uncommon in Huntington’s disease. It was most likely secondary to the disruptive effects of chorea in the aerodigestive tract. To our knowledge there has been no report regarding spastic esophageal dysmotility in Huntington’s disease. The cause of the spastic esophageal motility disorder in the patient was unknown. There are a few studies documenting acid reflux-induced esophageal spasm[12,14,15]. Simultaneous contractions from gastroesophageal reflux should be treated first by a proton pump inhibitor[16]. Reflux esophagitis in this case may be considered the cause of the esophageal dysmotility with a spastic component. However, there was no improvement under therapy with a proton pump inhibitor.

Considering dysphagia associated with chest pain attributable to esophageal spasm, subsequent trials of a nitrate, a calcium channel blocker, and a phosphodiesterase inhibitor were performed. There was no response to these drugs in the patient. Actually current treatments for esophageal spasm, including calcium channel blockers and nitrate donors, are limited by poor efficacy and side effects[17]. Recently botulinum toxin injections in the lower esophagus and at the level of the gastroesophageal junction have been reported to have a beneficial effect in patients suffering from DES[18-20]. These beneficial effects of botulinum toxin are perhaps related to the improved manometric results. Interestingly, injection of botulinum toxin in this case showed improvement in impedance results and symptoms despite no improved manometry results. It suggests that the esophageal symptoms are more closely related to disturbed bolus transport and impaired clearance than esophageal dysmotility per se[4]. It may also suggest that esophageal dysmotility in terms of abnormal contractility and impaired bolus transit is limited in explaining the dysphagia. Dysphagia symptoms are related to factors other than esophageal dysmotility, e.g., esophageal sensitivity disorder.

In conclusion, HRIM enabled us to obtain more detailed and important information in the Huntington’s disease patient with both oropharyngeal dysphasia and esophageal spastic dysmotility. Further investigation of HRIM will be needed to assess its role in either oropharyngeal or esophageal dysphagia.