GI Motility and Physiologic Function Testing Flashcards

A patient is scheduled for 96-hour wireless (Bravo) esophageal pH monitoring 'off therapy' to confirm GERD. How long before the study should proton pump inhibitors usually be stopped?

Answer: 7 days

PPIs suppress acid for several days, so they are usually stopped about 7 days before off-therapy pH testing. If they are not stopped, acid exposure can be falsely low and true GERD can be missed. H2 blockers are usually held for about 48 hours.

High-resolution esophageal manometry shows an elevated integrated relaxation pressure (IRP) and 100% failed peristalsis. Under the Chicago Classification, which diagnosis fits best?

Answer: Achalasia

Achalasia is defined by poor relaxation of the lower esophageal sphincter (elevated IRP) together with absent or failed peristalsis. Jackhammer esophagus and distal spasm show contractions that are too strong or come too early. Ineffective motility shows weak contractions with normal LES relaxation.

Which instruction is appropriate for a patient preparing for a hydrogen breath test for small intestinal bacterial overgrowth (SIBO)?

Answer: Avoid antibiotics for about 4 weeks before and fast overnight

Recent antibiotics change gut flora and can cause a false-negative result. Patients usually avoid antibiotics for about 4 weeks, eat a low-fermentable diet the day before, and fast for about 12 hours. Fiber, laxatives and gum can all change hydrogen readings.

During a standard 4-hour solid-meal gastric emptying scintigraphy study, which finding indicates delayed gastric emptying?

Answer: More than 10% retention at 4 hours

With the standardized low-fat egg-white meal, more than 10% of the meal still in the stomach at 4 hours means delayed emptying, consistent with gastroparesis. Very fast emptying in the first hour points instead to rapid emptying or dumping.

Before a urea breath test for Helicobacter pylori, which medications should be held to avoid a false-negative result?

Answer: PPIs for about 2 weeks and antibiotics/bismuth for about 4 weeks

PPIs, antibiotics and bismuth suppress H. pylori urease activity. That reduces the labeled CO2 the patient breathes out, which can give a false-negative result. PPIs are usually held about 2 weeks and antibiotics/bismuth about 4 weeks.

Anorectal manometry with a balloon expulsion test is most commonly ordered to evaluate which condition?

Answer: Dyssynergic defecation (pelvic floor dysfunction)

Anorectal manometry measures sphincter pressures, rectal sensation and the recto-anal reflexes. The balloon expulsion test checks whether the patient can evacuate. Together they are used to evaluate chronic constipation from dyssynergic defecation, and fecal incontinence.