Disorders of the Stomach

Definition

• typical esophageal symptoms (heartburn) responsive to PPI is sufficient for diagnosis

  • however, heartburn has only modest sensitivity/specificity for GERD

  • cost effective to assess symptom response but with low positive predictive value for GERD due to placebo effect

• intestinal metaplasia on distal esophageal biopsy is conclusive evidence of GERD

  • correlates well with distal esophageal acid exposure time

  • hiatal hernia and ineffective esophageal motility may predict higher esophageal acid burden, but these are not pathognomonic of GERD and can be seen without significant GERD

• pH monitoring OFF PPI therapy can also be used to diagnose or rule out GERD

• pH impedance monitoring ON PPI therapy is indicated in those with proven GERD (prior esophagitis, peptic stricture, Barrett's esophagus, abnormal pH study) to establish mechanism of ongoing symptoms

  • escalation of management can be considered and antireflux surgery can be offered if

    • regurgitation correlates with reflux episodes

    • a high number of reflux episodes are identified

    • acid exposure time is elevated

  • gastric emptying study can determine if gastroparesis could be contributing to regurgitation if pH impedance testing is negative

• gastric acid production is not increased in typical GERD

• proximal gastric distension is a prime trigger for TLESR, the most frequent mechanism for GERD

  • in the post prandial state, gastric acid produced by the stomach layers on top of the ingested meal

  • this pool of acidic gastric content (acid pocket) is in close proximity to the esophagogastric junction

    • can extend into a hiatal hernia or even distal esophagus in some cases

    • acid pocket increases the volume of acid reflux during TLESR

    • it does NOT increase gastric acid production or size of hiatal hernia

    • it does NOT influence TLESR frequency 

  • gastric emptying is independent of the presence/absence of an acid pocket

• H pylori infection is associated with reduced gastric acid production 

  • long term infection with atrophic gastritis can be associated with achlorhydria

  • time to recurrence of reflux symptoms following PPI is longer in those with H pylori

  • risk of Barrett's is lower

  • eradication of H pylori increases reflux symptoms, but does not increase reflux complications

Risk Factors

• male gender and obesity are risk factors for reflux esophagitis and Barrett's esophagus

• esophageal perception is enhanced in affective disorders including...

  • anxiety

  • sleep deprivation

  • stressful states

  • hypervigilance

• elderly have reduced esophageal perception and can have advanced esophageal erosive disease with limited symptoms

• Barrett's esophagus and diabetes are also associated with reduced esophageal perception

• Theophylline can reduce basal LES pressure and promote symptomatic GERD

• Beta adrenergic agonists can increase reflux

  • beta blockers do not impact reflux

• NSAIDs do NOT increase reflux tendency, but are mucosal irritants if retained in the esophagus

• women have lower rates of complicated reflux disease

• African Americans have lower rates of complicated reflux disease

Endoscopic Findings

• esophageal pH monitoring

  • used to clarify esophageal reflux burden, especially if symptoms persist after acid suppression

  • testing ON therapy - appropriate when diagnosis of GER is not in question and goal is to gauge adequacy of therapy

  • testing OFF therapy - appropriate when diagnosis of GERD is uncertain

  • wireless pH monitoring has a single recording site on a pH capsule placed in the esophagus 6 cm proximal to the endoscopically identified squamocolumnar junction 

    • since there is only a single site of pH recording, acidic swallows cannot be differentiated from acid reflux

      • patients must keep a careful diary to compare to recording findings

    • alkaline reflux is not detected 

    • esophageal shortening does not affect wireless pH monitoring but may affect catheter based pH recordings

  • catheter based pH monitoring

    • an improperly placed catheter tip can dip into the stomach during esophageal shortening

  • assess acid exposure time 

    • abnormal exposure time indicates need for PPI therapy

    • a physiologic (normal) acid exposure time suggests an alternate mechanism for symptoms

    • may be falsely elevated by acidic food/beverage swallows

    • antacids neutralize gastric acid and may reduce exposure time

    • post nasal drip does not impact exposure time

  • clustering of reflux episodes in the postprandial period

  • assess for nocturnal reflux episodes

Imaging Findings

• Reflux seen on barium swallow does NOT correlate with 

  • symptoms

  • acid burden on pH testing

  • symptom response to antireflux therapy

Treatment

• Anyone with chest pain should first undergo a cardiac work up before being evaluated for GERD or GI disorders

• Lifestyle modification

  • avoid late night meals

  • head of the bed elevation

• Proton pump inhibitors

  • Pantoprazole - lowest potency

  • lansoprazole

  • omeprazole

  • esomeprazole

    • S-isomer of omeprazole, better bioavailability due to slower elimination

    • may provide better response in equivalent doses

  • rabeprazole - highest potency

  • symptom frequency >2d per week suggests use of chronic acid suppression with PPI is appropriate

    • this should be at the lowest dose necessary to manage symptoms

  • Response to antireflux therapy including PPI is predicted by

    • Abnormal acid exposure on pH monitoring 

    • presence of erosive esophagitis

  • PPI side effects

    • equivocal data on associated risks including cardiovascular disease, dementia, pneumonia, C diff

    • fundic gland polyps (odds ratio 2.2)

    • chronic kidney injury (odds ratio 1.7) - though to due to repeated idiosyncratic interstitial nephritis

    • bone fracture (odds ration 1.4) - no increased risk of hip fracture

  • PPI failure

    • poor compliance with inappropriate administration (most important reason)

    • Take 30-60 min prior to melas for optimal physiologic gastric acid inhibition

    • Taking with morning meal favored over evening as there is relatively more gastric acid production at this time

    • suboptimal response of heartburn to PPI therapy and reflux symptoms to standard reflux therapy are associated with

      • presence of functional bowel disorders (ex. IBS)

      • anxiety and depression - may be related to visceral hypersensitivity and hypervigilance

  • PPI is unlikely to help resolve...

    • post prandial regurgitation

    • reflux symptoms

    • hoarseness

    • globus sensation

    • chronic unexplained cough

  • PPI discontinuation

    • Rebound acid hypersecretion may occur when abruptly stopping PPIs

    • to avoid this, proceed with tapered step down approach

      • H2 blocker maintenance or on-demand PPI therapy

• Upper endoscopy in patients 60 y or older with dyspepsia and/or alarm features

  • if these criteria are not met, reasonable to proceed with a 4-8 wk course of PPI therapy

  • if there is no improvement with PPI, test for H pylori and treat if positive

• Baclofen can reduce TLESR frequency and reflux episodes

Definition

• Esophageal hypomotility

  • can improve following antireflux surgery (especially if pre-op manometry shows contraction reserve)

• SIBO is NOT associated with antireflux surgery

Pre-operative work up

• high resolution manometry to exclude major motor disorder prior to surgery

• fundoplication in the setting of obesity has higher rates of recurrence of symptoms

  • in the setting of medically complicated obesity, gastric bypass may be the best anti-reflux procedure

  • magnetic sphincter augmentation has promising results in BM <35 and hiatal hernia <3 cm, no data for higher BMI

Complications

• Early post-operative dysphagia

  • common, a known consequence of successful antireflux surgery

  • likely related to post-op edema

  • typically improves without intervention

• Late post-operative dysphagia

  • persisting beyond or occurring after 3 mo after surgery

  • occurs in 6-25% and can be due to 

    • wrap dysfunction

    • esophageal hypomotility

    • recurrent complicated reflux

  • Risk factors

    • pre-operative dysphagia

    • absence of contraction reserve on pre-operative manometry

• Accelerated solid phase gastric emptying following fundoplication

  • due to altered gastric accommodation

  • likely occurs unless there is vagal injury

• Belching and regurgitation

  • typically improve following antireflux surgery

  • recurrence may be a sign of wrap dysfunction 

• Wrap dysfunction

  • assess fundoplication on EGD

    • slipped fundoplicaiton with recurrent hiatal hernia 

      • may have dysphagia and odynophagia, especially with a recurrent paraesophageal hernia

  • assess for erosive esophagitis and esophageal stricture which may be contributing to symptoms

  • Barium radiograph can complement evaluation with EGD

    • establish relationship of fundoplication to the esophagogastric junction

  • CT can show hiatal hernia but is not the most efficient method for diagnosing wrap dysfunction

• trans-diaphragmatic wrap herniation

  • wrap migration above the hiatus

• slipped Nissen or malpositioned wrap

  • gastric folds are seen proximal to the wrap impression and the wrap is seen around the stomach rather than the GEJ

• Tight wrap

  • passage of the scope may encounter resistance

  • proximal dilation may be seen

• Complete disruption

  • complete loss of the folds of the fundoplication

• Vagal nerve injury

  • known adverse event, especially after redo procedures

  • results in delayed gastric emptying

Complications

• gastric sleeve may cause de novo reflux or worsen pre-existing symptoms

Treatment

• Behavioral therapy

  • diaphragmatic breathing

Treatment

• Upper endoscopy in patients 60 y or older with dyspepsia and/or alarm features

  • if these criteria are not met, reasonable to proceed with a 4-8 wk course of PPI therapy

  • if there is no improvement with PPI, test for H pylori and treat if positive

Definition

• lack of response to PPI (compared to erosive esophagitis or PUD)

• normal EGD

Treatment

• amitriptyline

Treatment

• buspirone

  • a 5-HT1A agonist

  • has clinical efficacy for patients with anxiety

  • improves post-prandial fullness, bloating, and early satiety

    • several mechanisms likely independent of anxiolytic properties 

    • delay in liquid gastric emptying rate

    • increase in meal-induced fundic relaxation and accommodation 

  • does NOT improve abdominal pain

Diagnosis

• presence of the following for 3 or more months

  • burning retrosternal pain/discomfort

  • no relief with antacid medication

  • no evidence of GERD, eosinophilic esophagitis, or other motility disorders

Definition

• results from inflammatory proliferation of mucous producing gastric foveolar cells

  • often in the setting of chronic bile exposure

  • frequently associated with mucosal atrophy but may be seen in absence of autoimmune gastritis or H pylori infection

Signs and Symptoms

• iron deficiency anemia

• intermittent gastric outlet obstruction

  • due to prolapsing of large hyperplastic polyps 

Definition

• commonly found on EGD, especially in those treated with PPIs

• genernally hav elow risk for malignant transformation

• dysplasia is associated with 

  • increasing size of the largest fundic gland polyps

  • presence of antral gastritis

  • history of familial adenomatous polyposis (FAP) syndrome

• Barrett's esophagus is NOT associated with dysplastic fundic glad polyps

Definition

• frequent cause of non-ulcer dyspepsia

• most common infection worldwide 

  • though incidence and prevalence are not uniformly distributed

  • US as a whole as relatively lower prevalence, primarily within higher socioeconomic subgroups

  • African Americans and Latinos have prevalence approaching those of developing countries

• Corpus predominant H pylori gastritis noted in those from southeast Asia

• H pylori infection is associated with reduced gastric acid production 

  • long term infection with atrophic gastritis can be associated with achlorhydria

  • time to recurrence of reflux symptoms following PPI is longer in those with H pylori

  • risk of Barrett's is lower

  • eradication of H pylori increases reflux symptoms, but does not increase reflux complications

Lab Findings

• Urea breath test

  • 95% sensitivity, 95% specificity

• Stool antigen

  • 93% sensitivity, 90% specificity

• Serum antibody

  • non-specific for active infection

• Corpus gastritis - associated with gastric atrophy

  • High gastrin

  • High gastric pH

  • increased parietal cell mass

Pathology Findings

• histology is the gold standard for documenting H pylori infection

• Corpus gastritis - intestinal metaplasia often seen

Treatment

• Bismuth based quadruple therapy

  • 14 day course

  • PPI + bismuth + metronidazole + tetracycline

• Save rifabutin containing regimen for treatment failure or salvage

  • PPI + rifabutin + amoxicillin

• Antibiotic resistance

  • amoxicillin resistance is estimated to be <1%

  • clarithromycin and metronidazole are the most prone to resistance 

  • triple therapy is no longer effective in a large subset of patients including those from the far east

    • current recommendation is to start quadruple therapy in these patients

    • PPI + amoxicillin + clarithromycin + metronidazole

  • exposures to multiple recent antibiotics reduces likelihood of response to triple therapy

    • PPI + amoxicillin + clarithromycin

    • PPI + amoxicillin + levofloxacin

• Treatment failure

  • if there is a penicillin allergy and the patient has failed 1 or 2 courses of HP therapy

    • send for allergy testing given efficacy of amoxicillin

    • may also consider levofloxacin based therapies

Screening

• there is no recommendation for routine EGD in those with H pylori without history suggestive of increased cancer risk

• those with first degree relatives with H pylori are at increased risk

  • given association with gastric cancer, those with family history of gastric cancer would benefit from H pylori testing

Definition

• can occur in the setting of polyglandular autoimmune syndrome

• can progress to pernicious anemia, characterized by low vitamin B12

• loss of parietal cells leads to 

  • loss of intrinsic factor secretion required for B12 absorption 

  • atrophic gastritis

Lab Findings

• anti-parietal cell antibody - most sensitive test (80%)

• anti-intrinsic factor antibody - less sensitive (50%)

• Schilling test

  • can provide insight into etiology of B12 deficiency, ex. issues with IF production vs malabsorption

  • however, it is rarely available

• serum homocysteine elevation

  • very sensitive for B12 deficiency but cannot identify cause and may be affected by renal insufficiency 

• Pernicious anemia

  • high gastrin

  • high gastric pH

  • negative secretin stimulation test

Complications

• vitamin B12 deficiency

  • folate deficiency is not seen

Lab Findings

• elevated methyl-malonic acid levels

Definition

• most common causes of ulcer disease are H pylori and NSAID use

  • in the immunocompromised consider testing for viral infection (ex. CMV) on biopsy specimens

Risk Factors

• NSAID use

  • COX-1 inhibition results in inhibition of prostaglandin synthesis, which helps to maintain the protective mucosal barrier

    • this is a systemic effect so enteric coated preparations do not reduce the risk of PUD

  • ibuprofen - lowest risk

  • naproxen - highest risk

• co-incidence of H pylori and NSAID use

• oral iron

• alendronate

Treatment

Definition

• can be secondary to a large ulcer with edema and associated deformity

Signs and Symptoms

• abdominal distension, tenderness

• succession splash (sloshing sound)

Lab Findings

• elevated gastrin level

  • due to antral distension which leads to acetyl choline release stimulating parietal cells to secrete acid

  • interacts with G cells to release gastrin

• low gastric pH

Definition

• can result in NSAID induced ulcers

Lab Findings

• Gastrin level

  • post prandial testing and testing done while on PPI can lead to higher gastrin levels

Signs and Symptoms

• associated with MEN1 

  • autosomal dominant

  • pituitary tumors (hyperprolactinemia leading to gynecomastia)

  • hyperparathyroidism (hypercalcemia)

  • pancreatic tumor (leading to ZES)

• weight loss

  • direct catabolic tumor effects, particularly in those with metastatic disease

  • gastric acid hypersecretion and associated diarrhea can lead to fat and other nutrient malabsorption

    • once appropriately medically treated, frequency of bowel movements is reduced

• abdominal pain

  • does not always lead to reduction in oral intake

• duodenal ulcers unresponsive to PPI

Lab Findings

• Gastrin level elevated, typically >1000 pg/mL

  • PPI therapy will elevate gastrin levels but not to this degree

• Basal acid output elevated 

• peak acid output (following pentagastrin administration) 

• Ideally the above tests should be done off PPI therapy

Endoscopic Findings

• post bulbar ulcer

• thickened gastric folds

Treatment

• PPIs are indicated and effective in controlling secondary effects of ZES, but do not have primary anti-neoplastic effects

Definition

• gastric carcinoids arise in enterochromaffin-like (ECL) cells

• Type 1

  • most common

  • most commonly associated with chronic atrophic gastritis

  • lowest metastatic risk (<5%)

• Type 2

  • associated with Zollinger-Ellison syndrome and MEN-1

  • metastatic risk ~10%

• Type 3

  • sporadic 

  • highest malignant potential, metastatic risk 50%

Definition

• Acute vs chronic

• Primary Gastric Volvulus

  • related to abnormalities in gastric ligaments (gastrophrenic, gastrosplenic, gastrocolic, gastrohepatic)

• Secondary Gastric Volvulus

  • more common (2/3 of cases)

  • related to anatomic abnormalities such as paraesophageal hernia, diaphragmatic hernia, and phrenic nerve paralysis among others

• Types of rotation

  • Organoaxial

    • most common

    • rotation along the stomach's long axis

    • strangulation more common

  • Mesenteroaxial

    • rotation along the stomach's short axis

    • typically <180 degree rotation

  • Complex

    • combination of organoaxial and mesenteroaxial rotation

Signs and Symptoms

• Borchardt's triad

  • pain

  • vomiting

  • inability to pass nasogastric tube

• Gastric outlet obstruction

• Hematemesis 

  • related to ischemia or ulceration

• Abdominal distension

  • may be less prominent in chronic gastric volvulus

Treatment

• Resuscitation with IVF and electrolytes repletions

• NG tube gastric decompression

  • may be done with or without endoscopic guidance

• Emergent surgery in the case of...

  • failed gastric decompression

  • evidence of gastric ischemia or necrosis

  • gastric perforation

  • shock or severe sepsis

• If clinically stable with adequate decompression, may consider consider delayed definitive repair with surgery

• Gastric fixation

  • for primary gastric volvulus

  • PEG placement (leave in place for 6-12 wks then remove after adhesions form) or surgical gastropexy

• Surgical repair of anatomic defect (ex. hernia reduction)

  • for secondary gastric volvulus

  • gastric fixation alone not recommended