Nitin K. Ahuja

What is the clinical significance of esophagogastric junction outflow obstruction? evaluation of 60 patients at a tertiary referral center

Esophagogastric junction (EGJ) outflow obstruction (EGJOO) is characterized by impaired EGJ relaxation with intact or weak peristalsis. Our aims were to evaluate: (i) prevalence, (ii) yield of fluoroscopy, endoscopy, and endoscopic ultrasound (EUS), (iii) outcomes, and (iv) whether this data differed based on quantitative EGJ relaxation.

It Feels Good to Be Measured: Clinical Role-Play, Walker Percy, and the Tingles

A large online community has recently formed around autonomous sensory meridian response (ASMR), a pleasant and poorly understood somatic reaction to specific interpersonal triggers. Its web-based manifestations include a variety of amateur videos designed to elicit the reaction, many of which feature protracted imitations of a clinician’s physical exam. This analysis considers through a literary lens the proximity of this phenomenon to clinical diagnostics, focusing in particular on characterizations of spiritual isolation elaborated in Love in the Ruins (1971), the third novel by physician-writer Walker Percy (1916–1990). Within this speculative framework, the tendency to derive pleasure from clinical milieus, real or constructed, may be interpreted as a quality particular to the postmodern psyche. Viewing web-based clinical role-play in light of Percy’s writing also underscores the possibility that routine diagnostic assessments may have independent therapeutic implications.

Pyloric Therapies for Gastroparesis

Opinion statementGastroparesis is a syndrome that can be difficult to treat effectively and likely represents the common clinical presentation of multiple underlying mechanisms. One of these presumed mechanisms involves pyloric dysfunction, tied perhaps to spasm or fibrosis, manifesting as functional gastric outlet obstruction. Various diagnostic modalities have been used to better characterize this hypothesized abnormality, including most recently antroduodenal manometry and impedance planimetry. A variety of therapeutic interventions specific to the pylorus have also been proposed in the last several years, including intrapyloric injections of botulinum toxin, transpyloric stenting, surgical pyloroplasty, and endoscopic pyloromyotomy. The clinical application of these maneuvers has been mostly empiric thus far, but efforts are ongoing to identify the subset of patients whose physiology best positions them to benefit from such therapy. Early results for many of these interventions have been promising and will serve as the basis for larger and more systematic research frameworks moving forward.

Precision Bariatrics: Toward a New Paradigm of Personalized Devices in Obesity Therapeutics

The prevalence and complexity of obesity and its associated metabolic complications highlight the importance of building a rigorous investigative framework for the development of novel weight loss therapies. Device-based interventions in particular constitute a market poised for rapid expansion in the coming years. Optimizing outcomes for this new class of therapies requires attention to an evolving taxonomy of subdivisions within the broader obesity phenotype and a means for stratifying patients toward maximally effective interventions. Extant bariatric devices implicitly prioritize anatomic variables as surrogates for physiology, a somewhat arbitrary assumption that merits empiric validation. Utilizing the governing principles of systems biology and recent innovations in clinical trial design, a robust and precise research infrastructure can and should be developed to more effectively mitigate this contemporary epidemic.

Performance of Endoscopic Ultrasound in Staging Rectal Adenocarcinoma Appropriate for Primary Surgical Resection

BACKGROUND & AIMS Endoscopic ultrasound (EUS) often is used to stage rectal cancer and thereby guide treatment. Prior assessments of its accuracy have been limited by small sets of data collected from tumors of varying stages. We aimed to characterize the diagnostic performance of EUS analysis of rectal cancer, paying particular attention to determining whether patients should undergo primary surgical resection. METHODS We performed a retrospective observational study using procedural databases and electronic medical records from 4 academic tertiary-care hospitals, collecting data on EUS analyses from 2000 through 2012. Data were analyzed from 86 patients with rectal cancer initially staged as T2N0 by EUS. The negative predictive value (NPV) was calculated by comparing initial stages determined by EUS with those determined by pathology analysis of surgical samples. Logistic regression models were used to assess variation in diagnostic performance with case attributes. RESULTS EUS excluded advanced tumor depth with an NPV of 0.837 (95% confidence interval [CI], 0.742-0.908), nodal metastasis with an NPV of 0.872 (95% CI, 0.783-0.934), and both together with an NPV of 0.767 (95% CI, 0.664-0.852) compared with pathology analysis. Incorrect staging by EUS affected treatment decision making for 20 of 86 patients (23.3%). Patient age at time of the procedure correlated with the NPV for metastasis to lymph node, but no other patient features were associated significantly with diagnostic performance. CONCLUSIONS Based on a multicenter retrospective study, EUS staging of rectal cancer as T2N0 excludes advanced tumor depth and nodal metastasis, respectively, with an approximate NPV of 85%, similar to that of other modalities. EUS has an error rate of approximately 23% in identifying disease appropriate for surgical resection, which is lower than previously reported.

The Role of Impedance Planimetry in the Evaluation of Esophageal Disorders

Purpose of ReviewImpedance planimetry measures tissue wall distensibility as a function of pressure and cross-sectional area. Recent interest in this technique’s relevance to the gastrointestinal tract has been accelerated by the availability of the functional lumen imaging probe, a catheter-based system that dynamically quantitates these biomechanical properties. Herein, we review the device’s particular utility in the setting of esophageal pathology, including processes affecting the esophageal body as well as the upper and lower esophageal sphincters.Recent FindingsAn expanding suite of disease-specific indications for impedance planimetry includes achalasia, gastroesophageal reflux disease, and eosinophilic esophagitis. The technique has also demonstrated a role in the intraoperative guidance of therapy and in the definition of hitherto unrecognized patterns of esophageal dysmotility.SummaryDevice-specific technology remains in active evolution, which, in conjunction with progressively larger datasets, sets the stage for broader clinical applicability in the near future.

Assessing Upper Esophageal Sphincter Function in Clinical Practice: a Primer.

The upper esophageal sphincter constitutes an important anatomic and functional landmark in the physiology of pharyngeal swallowing. A variety of clinical circumstances may call for a dedicated evaluation of this mechanism, from the etiologic evaluation of indeterminate symptoms to the generation of complex locoregional therapeutic strategies. Multiple diagnostic tools exist for the assessment of pharyngeal swallowing generally and of upper esophageal sphincter function specifically, some well established and others not yet settled into routine practice. This report reviews five specific modalities for use in making this assessment, outlining the strengths, weaknesses, and logistical considerations of each with respect to its potential use in clinical settings. In many cases, these studies will provide complementary information regarding pharyngeal function, suggesting the relative advantage of a multimodal evaluation.

Evaluation and Management of Infectious Esophagitis in Immunocompromised and Immunocompetent Individuals

Opinion statementAmong the many inflammatory processes that may account for esophageal symptoms, infection represents an important etiologic category with numerous clinically relevant subdivisions. While features of the history and physical exam are informative, diagnosis often hinges on endoscopic visualization and histopathologic analysis. This chapter will review in series the most clinically relevant causative agents for infectious esophagitis, with specific diagnostic and therapeutic features of note divided into one of two immune milieus. Our discussion focuses primarily on Candida species, herpes simplex virus, and cytomegalovirus as the most common causes of infectious esophagitis while also addressing a number of less common pathogens worth keeping in mind.

The Relevance of Spastic Esophageal Disorders as a Diagnostic Category

Purpose of ReviewThis review addresses the similarities and differences between the spastic esophageal disorders, including jackhammer esophagus, distal esophageal spasm (DES), and type III (spastic) achalasia. The pathophysiology, diagnosis, and treatment of each separate disorder are discussed herein, with an emphasis on overlapping and discordant features.Recent FindingsThe Chicago Classification is a hierarchical organizational scheme for esophageal motility disorders, currently in its third iteration, with direct impact on the definitions of these three disorders. Complementary diagnostic tools such as impedance planimetry and novel manometric parameters continue to evolve. The suite of potential treatments for these disorders is also expanding, with progressive interest in the role of peroral endoscopic myotomy alongside established pharmacologic and mechanical interventions.SummaryAlthough jackhammer esophagus, distal esophageal spasm, and type III achalasia frequently overlap in terms of their clinical presentation and available management approaches, the divergences in their respective diagnostic criteria suggest that additional study may reveal additional mechanistic distinctions that lead in turn to further refinements in therapeutic decision-making.

POEM: Concept to Research Laboratory

Given that the first experiments involving submucosal endoscopic esophageal myotomy in a porcine model were published in 2007, the interval uptake of peroral endoscopic myotomy (POEM) into clinical practice has been impressively swift. While the procedure remains limited to specialized practitioners and centers, it has become a valuable therapeutic option for the management of achalasia with outcomes that rival benchmarks established by more conventional surgical alternatives. Historical perspective helps to contextualize POEM as the conceptual outgrowth of a much longer therapeutic lineage rather than a de novo innovation to be added to the proceduralist’s armamentarium. Reflecting on the specific differences between submucosal endoscopic myotomy and the interventions (both experimental and established) that preceded it allows for a clearer understanding of the ways in which POEM represents a novel therapeutic paradigm, for spastic esophageal disorders in particular and for endoscopy in general. Looking ahead, distant milestones in this conceptual evolution might include technical elaboration made possible by novel endoscopic devices or, intriguingly, molecular therapies that might render endoscopic therapy for achalasia obsolete.