Selective serotonin reuptake inhibitors for the treatment of hypersensitive esophagus: a randomized, double-blind, placebo-controlled study

Microscopic esophagitis distinguishes patients with non-erosive reflux disease from those with functional heartburn

BACKGROUND

Microscopic esophagitis (ME) is common in patients with non-erosive reflux disease (NERD), and dilation of intercellular spaces (DIS) has been regarded as the potential main mechanism of symptom generation. We aimed to compare these histological abnormalities in healthy volunteers (HVs) and patients with erosive esophagitis (EE), NERD, and functional heartburn (FH).

METHODS

Consecutive patients with heartburn prospectively underwent upper endoscopy and impedance-pH off-therapy. Twenty EE patients and fifty-seven endoscopy-negative patients (NERD), subclassified as 22 with pH-POS (positive for abnormal acid exposure), 20 with hypersensitive esophagus (HE; normal acid/symptom association probability [SAP]+ or symptom index [SI]+), and 15 with FH (normal acid/SAP-/SI-/ proton pump inhibitor [PPI] test-), were enrolled. Twenty HVs were also included. In each patient/control, multiple specimens (n = 5) were taken from the distal esophagus and histological alterations were evaluated. ME was diagnosed when the global histological score was >0.35.

RESULTS

The prevalence of ME was higher (p < 0.0001) in EE (95 %), pH-POS (77 %), and HE (65 %) NERD patients than in FH patients (13 %) and HVs (15 %). Also, basal cell hyperplasia (p < 0.0023), DIS (p < 0.0001), and papillae elongation (p < 0.0002) showed similar rates of prevalence in the above populations (p < 0.0001). ME, including each histological lesion, had similar low frequencies in FH and HVs (p = 0.9990). Considering the histological abnormalities together, they permitted us to clearly differentiate EE and NERD from FH and HVs (p < 0.0001 and p < 0.0001, respectively).

CONCLUSIONS

The lack of ME in the esophageal distal biopsies of FH patients indicates a limited role of these histological abnormalities in symptom generation in them. ME can be considered as an accurate and reliable diagnostic marker for distinguishing FH patients from GERD patients and has the potential to be used to guide the correct therapy.

Overlap of functional dyspepsia and GERD--diagnostic and treatment implications

GERD and functional dyspepsia are the two most prevalent upper gastrointestinal disorders. Gastro-oesophageal reflux is most commonly diagnosed using the cardinal symptoms of heartburn and regurgitation. Patients might also be diagnosed using a questionnaire, after empiric treatment with an acid suppressant, after upper endoscopy or by pH testing. Functional dyspepsia is best diagnosed using symptoms outlined by the Rome committee in conjunction with a normal upper endoscopy. Theoretically, distinguishing these two populations should be easy for all health-care providers. In reality, however, carefully separating out these two populations can be quite difficult, as substantial overlap exists epidemiologically, symptomatically and even diagnostically. This overlap renders precise diagnosis a challenge; given the limited treatment options, the primary goal is to identify those patients who will respond to acid suppressive therapy. Despite the frequency with which functional dyspepsia and GERD overlap, remarkably few studies have investigated this overlap. Most recommendations are based on data derived from separate studies of functional dyspepsia and GERD. A further limitation of existing studies is their failure to differentiate between the various diagnostic categories into which the individual presenting with heartburn might belong.

Functional heartburn: definition and management strategies

Functional heartburn (FH) is a functional gastro-intestinal disorder characterized by symptoms of heartburn not related to gastro-esophageal reflux. The absence of evidence of reflux-related symptoms relies on absence of esophagitis at endoscopy (including biopsies to exclude eosinophilic esophagitis), a normal esophageal acid exposure during esophageal pH-monitoring together with a negative symptom-reflux association analysis and an unsatisfactory response to proton pump inhibitor therapy. Addition of impedance measurement to pH-monitoring is likely to increase the number of patients with recognized reflux-related symptoms. The pathophysiology of functional heartburn remains largely unknown but involves disturbed esophageal perception and psychological factors such as depression, anxiety and somatization. The treatment of FH remains largely empirical and an individual approach is therefore recommended. The clinician should provide reassurance and refrain from performing too many invasive tests or therapeutic procedures. The use of pain modulators is recommended by most experts despite the lack of appropriate clinical trials to support it.

Selective-serotonin reuptake inhibitors for the treatment of hypersensitive esophagus

In patients with proton-pump inhibitor (PPI) resistant reflux symptoms, ambulatory 24 h pH impedance monitoring can be used to assess whether a relationship exists between symptoms and reflux episodes. Using this technique it has been suggested that patients with typical reflux symptoms and a normal upper endoscopy should be subclassified as follows: normal endoscopy and abnormal distal acid esophageal exposure (patients with acid reflux); normal endoscopy, with normal distal acid esophageal exposure and a positive symptom association for either acid or nonacid reflux (patients with hypersensitive esophagus); and normal endoscopy, normal distal acid esophageal exposure and a negative symptom association for acid and nonacid reflux (patients with functional heartburn). Although for patients with a normal endoscopy and abnormal distal acid esophageal exposure more aggressive acid suppression can be recommended, managing patients with hypersensitive esophagus and functional heartburn remains a real challenge.Therefore, investigators have evaluated the role of tricyclic antidepressants or selective-serotonin reuptake inhibitors (SSRIs) in influencing esophageal perception. Imipramine has been shown to decrease pain perception in healthy male volunteers and improve symptoms of patients with chest pain and normal coronary angiograms. Trazodone improved symptoms in patients with esophageal contraction abnormalities, while administration of SSRIs lowered chemical and mechanical sensitivity and benefited patients with diffuse esophageal spasm. Furthermore, in a recent study conducted by our group, citalopram administered once daily for 6 months was effective in a select group of patients with hypersensitive esophagus, suggesting that there is a role for SSRIs in the treatment of this disorder.