You are in: eMedicine Specialties > Gastroenterology > Stomach Gastritis, AcuteArticle Last Updated: Jul 30, 2008AUTHOR AND EDITOR INFORMATIONAuthor: Mohammad Wehbi, MD, Assistant Professor of Medicine, Associate Program Director, Department of Gastroenterology, Atlanta Veterans Affairs Medical Center, Emory University School of Medicine Mohammad Wehbi is a member of the following medical societies: American College of Physicians, American Gastroenterological Association, and American Medical Association Coauthor(s): Nicole M Griglione, MD, Staff Physician, Department of Medicine, Emory University School of Medicine; Richard H Snyder, MD, Vice-Chair, Program Director, Department of Medicine, Norfolk General Hospital; Clinical Associate Professor, Department of Internal Medicine, East Virginia Medical School; Gwendolyn Sarver, BS, Pennsylvania State University College of Medicine; Kamil Obideen, MD, Assistant Professor of Medicine, Division of Digestive Diseases, Emory University School of Medicine; Consulting Staff, Division of Gastrointestinal Endoscopy, Atlanta Veterans Affairs Medical Center; Vincent W Yang, MD, PhD, R Bruce Logue Professor, Director, Division of Digestive Diseases, Department of Medicine, Professor of Hematology and Oncology, Winship Cancer Institute, Emory University School of Medicine Editors: Waqar A Qureshi, MD, Chief of Endoscopy, Associate Professor, Department of Internal Medicine, Division of Gastroenterology, Baylor College of Medicine and VA Medical Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Simmy Bank, MD, Chair, Professor, Department of Internal Medicine, Division of Gastroenterology, Long Island Jewish Hospital, Albert Einstein College of Medicine; Alex J Mechaber, MD, FACP, Assistant Dean for Medical Curriculum, Associate Professor of Medicine, Division of General Internal Medicine, University of Miami Miller School of Medicine; Julian Katz, MD, Clinical Professor of Medicine, Drexel University College of Medicine; Consulting Staff, Department of Medicine, Section of Gastroenterology and Hepatology, Hospital of the Medical College of Pennsylvania Author and Editor Disclosure Synonyms and related keywords: acute gastritis, gastric mucosa inflammation, inflamed gastric mucosa, pangastritis, antral gastritis, erosive gastritis, nonerosive gastritis, non-erosive gastritis, Helicobacter pylori, H pylori, Candida albicans, C albicans, alcoholic gastritis, NSAIDs, nonsteroidal anti-inflammatory drugs, analgesic-induced gastritis, cytomegalovirus, fungal infection, histoplasmosis, stomach irritation, stomach ache, upset stomach INTRODUCTIONBackgroundAcute gastritis is a term covering a broad spectrum of entities that induce inflammatory changes in the gastric mucosa. The different etiologies share the same general clinical presentation. However, they differ in their unique histologic characteristics. The inflammation may involve the entire stomach (eg, pangastritis) or a region of the stomach (eg, antral gastritis). Acute gastritis can be broken down into 2 categories: erosive (eg, superficial erosions, deep erosions, hemorrhagic erosions) and nonerosive (generally caused by Helicobacter pylori). No correlation exists between microscopic inflammation (histologic gastritis) and the presence of gastric symptoms (eg, abdominal pain, nausea, vomiting). In fact, most patients with histologic evidence of acute gastritis (inflammation) are asymptomatic. The diagnosis is usually obtained during endoscopy performed for other reasons. Acute gastritis may present with an array of symptoms, the most common being nondescript epigastric discomfort. Other symptoms include nausea, vomiting, loss of appetite, belching, and bloating. Occasionally, acute abdominal pain can be a presenting symptom. This is the case in phlegmonous gastritis (gangrene of the stomach) where severe abdominal pain accompanied by nausea and vomiting of potentially purulent gastric contents can be the presenting symptoms. Fever, chills, and hiccups also may be present. The diagnosis of acute gastritis may be suspected from the patient's history and can be confirmed histologically by biopsy specimens taken at endoscopy. Epidemiologic studies reflect the widespread incidence of gastritis. In the See related CME at Evaluation of Acute Abdominal Pain Reviewed. PathophysiologyAcute gastritis has a number of causes, including certain drugs; alcohol; bile; ischemia; bacterial, viral, and fungal infections; acute stress (shock); radiation; allergy and food poisoning; and direct trauma. The common mechanism of injury is an imbalance between the aggressive and the defensive factors that maintain the integrity of the gastric lining (mucosa). Acute erosive gastritis can result from the exposure to a variety of agents or factors. This is referred to as reactive gastritis. These agents/factors include nonsteroidal anti-inflammatory medications (NSAIDs), alcohol, cocaine, stress, radiation, bile reflux, and ischemia. The gastric mucosa exhibits hemorrhages, erosions, and ulcers. NSAIDs, such as aspirin, ibuprofen, and naproxen, are the most common agents associated with acute erosive gastritis. This results from oral or systemic administration of these agents either in therapeutic doses or in supratherapeutic doses. Because of gravity, the inciting agents lie on the greater curvature of the stomach. This partly explains the development of acute gastritis distally on or near the greater curvature of the stomach in the case of orally administered NSAIDs. However, the major mechanism of injury is the reduction in prostaglandin synthesis. Prostaglandins are chemicals responsible for maintaining mechanisms that result in the protection of the mucosa from the injurious effects of the gastric acid. Long-term effects of such ingestions can include fibrosis and stricture. Bacterial infection is another cause of acute gastritis. The corkscrew-shaped bacterium called H pylori is the most common cause of gastritis. Complications result from a chronic infection rather than from an acute infection. The prevalence of H pylori in otherwise healthy individuals varies depending on age, socioeconomic class, and country of origin. The infection is usually acquired in childhood. In the Western world, the number of people infected with H pylori increases with age. Evidence of H pylori infection can be found in 20% of individuals younger than 40 years and in 50% of individuals older than 60 years. How the bacterium is transmitted is not entirely clear. Transmission is likely from person to person through the oral-fecal route or through the ingestion of contaminated water or food. This is why the prevalence is higher in lower socioeconomic classes and in developing countries. H pylori is associated with 60% of gastric ulcersand80%ofduodenal ulcers. H pylori gastritis typically starts as an acute gastritis in the antrum, causing intense inflammation, and over time, it may extend to involve the entire gastric mucosa resulting in chronic gastritis. The acute gastritis encountered with H pylori is usually asymptomatic. The bacterium imbeds itself in the mucous layer, a protective layer that coats the gastric mucosa. It protects itself from the acidity of the stomach through the production of large amounts of urease, an enzyme that catalyzes the breakdown of urea to the alkaline ammonia and carbon dioxide. The alkaline ammonia neutralizes the gastric acid in the immediate vicinity of the bacterium conferring protection. H pylori also has flagella that enable it to move and help it to penetrate the mucous layer so that it comes into contact with gastric epithelial cells. It also has several adhesions that help it to adhere to these cells. It produces inflammation by activating a number of toxins and enzymes that activate IL-8, which eventually attracts polymorphs and monocytes that cause acute gastritis. Antigen-presenting cells activate lymphocytes and other mononuclear cells that lead to chronic superficial gastritis. The infection is established within a few weeks after the primary exposure to H pylori. It produces inflammation via the production of a number of toxins and enzymes. The intense inflammation can result in the loss of gastric glands responsible for the production of acid. This is referred to as atrophic gastritis. Consequently, gastric acid production drops. The virulence genotype of the microbe is an important determinant for the severity of the gastritis and the formation of intestinal metaplasia, the transformation of gastric epithelium. This transformation can lead to gastric cancer. Reactive gastropathy is the second most common diagnosis made on gastric biopsy specimens after H pylori gastritis. This entity is believed to be secondary to bile reflux and was originally reported after partial gastrectomy (Billroth I or II). It is now considered to represent a nonspecific response to a variety of other gastric irritants.Helicobacter heilmanii is a gram-negative, tightly spiraled, helical-shaped organism with 5-7 turns. The prevalence of H heilmanii is extremely low (0.25-1.5%). The source of H heilmanii infection is unclear, but animal contact is thought to be the means of transmission. Tuberculosis is a rare cause of gastritis, but an increasing number of cases have developed because of patients who are immunocompromised. Gastritis caused by tuberculosis is generally associated with pulmonary or disseminated disease. Secondary syphilis of the stomach is a rare cause of gastritis. Phlegmonous gastritis is an uncommon form of gastritis caused by numerous bacterial agents, including streptococci, staphylococci, Proteus species, Clostridium species, and Escherichia coli. Phlegmonous gastritis usually occurs in individuals who are debilitated. It is associated with a recent large intake of alcohol, a concomitant upper respiratory tract infection, and AIDS. Phlegmonous means a diffuse spreading inflammation of or within connective tissue. In the stomach, it implies infection of the deeper layers of the stomach (submucosa and muscularis). As a result, purulent bacterial infection may lead to gangrene. Phlegmonous gastritis is rare. The clinical diagnosis is usually established in the operating room, as these patients present with an acute abdominal emergency requiring immediate surgical exploration. Without appropriate therapy, it progresses to peritonitis and death. Viral infections can cause gastritis. Cytomegalovirus (CMV) is a common viral cause of gastritis. It is usually encountered in individuals who are immunocompromised, including those with cancer, immunosuppression, transplants, and AIDS. Gastric involvement can be localized or diffuse. Fungal infections that cause gastritis include Candida albicans and histoplasmosis. Gastric phycomycosis is another rare lethal fungal infection. The common predisposing factor is immunosuppression. C albicans rarely involves the gastric mucosa. When isolated in the stomach, the most common locations tend to be within a gastric ulcer or an erosion bed. It is generally of little consequence. Disseminated histoplasmosis can involve the stomach. The usual presenting clinical feature is bleeding from gastric ulcers or erosions on giant gastric folds. Parasitic infections are rare causes of gastritis. Anisakidosis is caused by a nematode that embeds itself in the gastric mucosa along the greater curvature. Anisakidosis is acquired by eating contaminated sushi and other types of contaminated raw fish. It often causes severe abdominal pain that subsides within a few days. This nematode infection is associated with gastric fold swelling, erosions, and ulcers. Ulcero-hemorrhagic gastritis is most commonly seen in patients who are critically ill. Ulcero-hemorrhagic gastritis is believed to be secondary to ischemia related to hypotension and shock or to the release of vasoconstrictive substances, but the etiology is often unknown. The gastric mucosa reveals multiple petechiae, mostly in the fundus and body, or exhibits a diffusely hemorrhagic pattern. The gross pathology may resemble that of NSAID- or other ingestion-induced gastritis, except that the location of injury is different. This form of gastritis can be life-threatening if the patient experiences hemorrhaging and may even require emergency gastrectomy. Microscopic evidence of acute gastritis can be seen in patients with Crohn disease, though clinical manifestations are rare (occurring in only about 2-7% of patients with Crohn disease). Focally enhancing gastritis is now recognized as a condition seen in both Crohn disease and ulcerative colitis. Eosinophilic gastritis is often seen in conjunction with eosinophilic gastroenteritis but can be associated with various disorders, including food allergies (eg, cow milk, soy protein), collagen vascular diseases, parasitic infections, gastric cancer, lymphoma, Crohn disease, vasculitis, drug allergies, and H pylori infections. An eosinophilic infiltrate is seen involving the gastric wall or epithelium. Mortality/MorbidityThe mortality/morbidity is dependent on the etiology of the gastritis. Generally, most cases of gastritis are treatable once the etiology is determined. The exception to this is phlegmonous gastritis, which has a mortality rate of 65%, even with treatment. SexNo sexual predilection exists. AgeGastritis affects all age groups. The incidence of H pylori infection increases with age. CLINICALHistory
PhysicalThe physical examination findings are often normal with occasional mild epigastric tenderness. The examination tends to exhibit more abnormalities as the patient develops complications in relation to gastritis. CausesAcute gastritis has a number of causes, including certain drugs; alcohol; bacterial, viral, and fungal infections; acute stress (shock); radiation; allergy and food poisoning; bile; ischemia; and direct trauma.
DIFFERENTIALSCholecystitis Cholelithiasis Crohn Disease Gastric Cancer Gastroenteritis, Viral Lymphoma, B-Cell Peptic Ulcer Disease Sarcoidosis
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| Drug Name | Aluminum and magnesium hydroxide, magnesia and alumina oral suspension (Rulox) |
|---|---|
| Description | Drug combination that neutralizes gastric acidity and increases pH of the stomach and duodenal bulb. Aluminum ions inhibit smooth-muscle contraction and inhibit gastric emptying. Magnesium/aluminum antacid mixtures are used to avoid bowel function changes. |
| Adult Dose | 5-15 mL PO; 650 mg to 1.3 g tab PO qid |
| Pediatric Dose | 0.5 mL/kg PO qid prior to eating |
| Contraindications | Documented hypersensitivity |
| Interactions | Decreases effects of allopurinol, amprenavir, chloroquine, corticosteroids, diflunisal, digoxin, ethambutol, iron salts, H2-antagonists, isoniazid, penicillamine, phenothiazines, tetracyclines, thyroid hormones, and ticlopidine; increases effects of benzodiazepines and amphetamine; may cause aluminum toxicity with ascorbic acid; aluminum and magnesium potentiate effects of valproic acid, sulfonylureas, quinidine, and levodopa |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Antacids may mask the symptoms of internal bleeding secondary to NSAIDs; magnesium-containing antacids may cause diarrhea and potentially lead to dehydration; caution with aluminum-containing antacids in patients who recently have had a massive upper GI hemorrhage |
This class includes drugs whose mechanism of action is competitive inhibition of histamine at the histamine 2 (H2) receptor. Histamine plays an important role in gastric acid secretion, thereby making H2 blockers effective suppressors of basal gastric acid output and acid output stimulated by food and the neurological system. When used alone, they are frequently used as antisecretory drugs in H pylori therapy regimens. There are different drugs with different potencies and half-lives (eg, cimetidine, ranitidine, famotidine, nizatidine). Cimetidine will be discussed below as a representative of this class of drugs.
| Drug Name | Cimetidine (Tagamet) |
|---|---|
| Description | Inhibits histamine at H2 receptors of gastric parietal cells, which results in reduced gastric acid secretion, gastric volume, and hydrogen concentrations. |
| Adult Dose | 150 mg PO qid; not to exceed 600 mg/d 50 mg/dose IV/IM q6-8h; not to exceed 400 mg/d |
| Pediatric Dose | Not established Suggested dose is 10-20 mg/kg/d PO/IV divided q6h; not to exceed 40 mg/d |
| Contraindications | Documented hypersensitivity |
| Interactions | Can increase blood levels of theophylline, warfarin, tricyclic antidepressants, triamterene, phenytoin, quinidine, propranolol, metronidazole, procainamide, and lidocaine |
| Pregnancy | B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals |
| Precautions | Elderly may experience confusional states; may cause impotence and gynecomastia in young males; may increase levels of many drugs; adjust dose or discontinue treatment if changes in renal function occur; may increase risk of necrotizing enterocolitis in premature infants |
Proton pump inhibitors are potent inhibitors of the proton (acid) pump (ie, the enzyme H+,K+-ATPase), located in the apical secretory membrane of the gastric acid secretory cells (parietal cell). Proton pump inhibitors can completely inhibit acid secretion and have a long duration of action. They are the most effective gastric acid blockers. Omeprazole will be discussed as a representative of this class of drugs.
| Drug Name | Omeprazole (Prilosec) |
|---|---|
| Description | Decreases gastric acid secretion by inhibiting the parietal cell H+/K+-ATPase pump. |
| Adult Dose | 20 mg PO bid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity |
| Interactions | May decrease effects of itraconazole and ketoconazole; may increase toxicity of warfarin, digoxin, and phenytoin |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Bioavailability may increase in the elderly |
Bacterial infections also can cause gastritis. The most common causative organism is H pylori. A number of therapeutic regimens are effective against H pylori. Single antimicrobial agents generally are not recommended because of the potential development of resistance.
Dual therapy includes a proton pump inhibitor plus amoxicillin (no longer recommended because eradication rates are 30-80%) or a proton pump inhibitor plus clarithromycin (eradication rate of roughly 71%). Adding a second antimicrobial agent is recommended for successful eradication.
Triple regimens are preferred in clinical practice. One drug is a proton pump inhibitor or a bismuth-based drug, the second drug is clarithromycin, and the third drug is amoxicillin or metronidazole. Quadruple therapy regimens (ie, 2 antibiotics, bismuth, antisecretory agent) generally are effective; however, because more drugs are prescribed and taken, increased adverse effects and decreased patient compliance can occur. This regimen is used in the event that triple therapy fails.
The decision of which medications to use is based on the following 4 criteria: (1) the different toxicities of the various medications, (2) the relative costs of each medication and regimen, (3) the emergence of antimicrobial-resistant bacteria, and (4) the level of patient compliance.
| Drug Name | Amoxicillin (Amoxil, Trimox) |
|---|---|
| Description | Interferes with synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria. |
| Adult Dose | 500 mg PO qid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity |
| Interactions | Reduces the efficacy of oral contraceptives |
| Pregnancy | B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals |
| Precautions | Adjust dose in patients with renal impairment |
| Drug Name | Tetracycline (Sumycin) |
|---|---|
| Description | Inhibits bacterial protein synthesis by binding with 30S and possibly 50S ribosomal subunit(s). |
| Adult Dose | 500 mg PO qid |
| Pediatric Dose | <8 years: Not recommended >8 years: Not established |
| Contraindications | Documented hypersensitivity; severe hepatic dysfunction |
| Interactions | Bioavailability decreases with antacids containing aluminum, calcium, magnesium, iron, or bismuth subsalicylate; can decrease effects of oral contraceptives, causing breakthrough bleeding and increased risk of pregnancy; tetracyclines can increase hypoprothrombinemic effects of anticoagulants |
| Pregnancy | D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus |
| Precautions | Photosensitivity may occur with prolonged exposure to sunlight or tanning equipment; reduce dose in patients with renal impairment; consider drug serum level determinations in prolonged therapy; tetracycline use during tooth development (last one half of pregnancy through age 8 y) can cause permanent discoloration of teeth; Fanconilike syndrome may occur with outdated tetracyclines |
| Drug Name | Metronidazole (Flagyl) |
|---|---|
| Description | Imidazole ring-based antibiotic active against various anaerobic bacteria and protozoa. |
| Adult Dose | 250 mg PO qid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity |
| Interactions | Cimetidine may increase toxicity of metronidazole; may increase effects of anticoagulants; may increase toxicity of lithium and phenytoin; disulfiramlike reaction may occur with orally ingested ethanol |
| Pregnancy | B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals |
| Precautions | Adjust dose in patients with hepatic disease; monitor for seizures and development of peripheral neuropathy |
| Drug Name | Clarithromycin (Biaxin) |
|---|---|
| Description | Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes and causing RNA-dependent protein synthesis to arrest. |
| Adult Dose | 500 mg PO bid/tid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity; coadministration of pimozide or cisapride |
| Interactions | Toxicity increases with coadministration of fluconazole, astemizole, and pimozide; clarithromycin effects decrease and GI adverse effects may increase with coadministration of rifabutin or rifampin; may increase toxicity of anticoagulants, cyclosporine, tacrolimus, digoxin, omeprazole, carbamazepine, ergot alkaloids, triazolam, and HMG CoA-reductase inhibitors; serious cardiac arrhythmias may occur with coadministration of cisapride; plasma levels of certain benzodiazepines may increase, prolonging CNS depression; arrhythmias and increase in QTc intervals occur with disopyramide; coadministration with omeprazole may increase plasma levels of both agents |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Coadministration with ranitidine or bismuth citrate is not recommended with CrCl <25 mL/min; administer one half dose or increase dosing interval if CrCl <30 mL/min; diarrhea may be sign of pseudomembranous colitis; superinfections may occur with prolonged or repeated antibiotic therapies |
Used in combination with antibiotics and proton pump inhibitors/H2 receptor antagonists to eradicate H pylori.
| Drug Name | Bismuth subsalicylate (Bismatrol, Pepto-Bismol) |
|---|---|
| Description | Drug combination that treats active duodenal ulcer associated with H pylori. |
| Adult Dose | 525 mg PO qid |
| Pediatric Dose | Not established |
| Contraindications | Documented hypersensitivity |
| Interactions | Coadministration with anticoagulants may increase risk of bleeding; may increase toxicity of aspirin and hypoglycemics; decreases effects of tetracyclines and uricosurics |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | May cause temporary and harmless darkening of tongue and/or black stool; alcohol consumption may cause abdominal cramps, nausea, and vomiting |
| Media file 1: Acute gastritis with superficial erosions. | |
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| Media file 2: Mucosal erythema and edema consistent with acute gastritis. | |
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Article Last Updated: Jul 30, 2008