Chapter 11: Gastrointestinal Disease
What is the a well-defined break in the GI mucosa, at least 0.5 mm in diameter, called?
Where do peptic ulcer develop principally?
Tn regions of the GI tract that are proximal to acid and pepsin secretions.
Peptic ulcer disease is one of the most common human ailments. What are the risk factors for peptic ulcer disease? (3)
- NSAID use
Peptic ulcers result when the balance between aggressive factors and defensive factors is disrupted. What is the primary aggressive factor in peptic ulcer disease?
The primary aggressive factor in peptic ulcer disease is H. pylori. What type of bacteria is H. pylori?
H. pylori is a microaerophilic, gram-negative, spiral-shaped motile bacillus with four to six flagella.
What virulence factor produced by H. pylori hydrolyzes urea to ammonia and carbon dioxide, protecting the bacteria from the acidic environment and causing damage to the mucosa?
What are the only known hosts of H. pylori?
Use of NSAIDs is an etiologic factor in about 15% of cases of peptic ulcer. How do NSAIDs contribute to peptid ulcer disease?
These drugs directly damage mucosa, reduce mucosal prostaglandin production, and inhibit mucus secretion.
Where do peptic ulcers caused by NSAIDs use typically occur?
Ulcers caused by NSAIDs are located more often in the stomach than in the duodenum.
What is the proposed mechanism for whereby infection with H. pylori results in PUD?
It produces proteases and increases gastrin release by G cells, which leads to increased gastric acid production, acute gastritis, and ulcer formation.
Peptic ulcers rarely undergo carcinomatous transformation. How does the location of the ulcer affect its propensity for malignancy?
Ulcers of the greater curvature of the stomach have a greater propensity for malignant degeneration.
Many patients with active peptic ulcer report no ulcer symptoms. What is the most significant symptom of PUD?
Long-standing, , sharply localized, recurrent epigastric pain, described as “burning” or “gnawing."
What are three symptoms that indicate a peptic ulcer located in the duodenum?
- manifests most on an empty stomach
- frequently awakens the patient at night
- is relived by ingestion of food, milk, or antacids
What symptom is useful in differentiating gastric ulcers from duodenal ulcers?
Duodenal ulcers usually improve with ingestion of food, whereas gastric ulcers do not.
What complication of peptic ulcer is indicated by increased discomfort, loss of antacid relief, or pain radiating to the back?
What complication of peptic ulcer is indicated by protracted vomiting a few hours after a meal?
gastric outlet obstruction
What complication of peptic ulcer is indicated by melena (bloody stools) or black tarry stools?
What are four laboratory tests used to diagnose peptic ulcer disease?
- rapid urease testing
- biopsy and staining
- urea breath tests (UBTs)
Nonendoscopic laboratory tests for PUD include urea breath tests (UBTs). How do these tests work?
These noninvasive tests involves the ingestion of carbon-labeled urea; degradation of urea by the bacillus releases 13C or 14C in expired carbon dioxide.
What is the treatment for PUD if the peptic ulcer is confined, uncomplicated, and H. pylori is not present?
An antisecretory drug, such as a proton pump inhibitor (PPI), is administered for 10 to 14 days.
What are the three classes of antisecretory drugs?
- histamine H2 receptor antagonists
- proton pump inhibitors (PPIs)
What are four histamine H2 receptor antagonists?
What are four proton pump inhibitors?
What are three dental considerations of histamine H2 receptor antagonist use?
- delayed liver metabolism of benzodiazepines
- joint symptoms with preexisting arthritis
- potentially increased serum salicylate levels with concurrent aspirin use
What are three dental considerations of proton pump inhibitor use?
- reduced absorption of ampicillin, ketoconazole, and itraconazole
- increased concentration of benzodiazepines, warfarin, and phenytoin
- can be associated with vitamin B12 deficiency
What is "triple therapy" for H. pylori infection in peptic ulcer disease?
Triple therapy for H. pylori infection consists of:
- PPI such as omeprazole 20 mg bid or lansoprazole 30 mg bid, esomeprazole 40 mg qd, plus
- clarithromycin 500 mg bid (or metronidazole 500 mg bid), plus
- amoxicillin 1 g bid
Therapy is typically given for 10 to 14 days.
What is "quadruple therapy" for H. pylori infection in peptic ulcer disease?
Quadruple therapy for H. pylori infection consists of:
- PPI (2 capsules of 30 mg of lansoprazole) plus
- bismuth subsalicylate 525 mg qid, plus
- metronidazole 500 mg qid, plus
- amoxicillin suspension 2 g qid (or 500 mg tetracycline qid)
Therapy is typically given for 10 to 14 days.
What is "salvage therapy" for H. pylori infection in peptic ulcer disease?
Salvage therapy for H. pylori infection consists of:
- levofloxacin 250–500 mg bid
- amoxicillin 1000 mg bid
- PPI bid
Therapy is typically given for 10 to 14 days.
What drugs should dentists use for pain management in patients with a history of PUD?
NSAIDs should be avoided because of the irritative effects of these drugs on the GI epithelium; acetaminophen is recommended instead.
If an NSAID must be prescribed to a dental patient with a history of PUD, which should be used?
If NSAIDs are used, a COX-2–selective inhibitor (e.g. celecoxib) given in combination with a PPI.
Antacids also impair the absorption of tetracycline, erythromycin, oral iron, and fluoride. What directions should be given to the patient to avoid this problem?
Antibiotics and dietary supplements should be taken 2 hours before or 2 hours after antacids are ingested.
What is H. pylori found in the oral cavity?
H. pylori is found in dental plaque and may serve as a reservoir of infection and reinfection.
What is a common oral complication of the use of systemic antibiotics for PUD?
fungal overgrowth (candidiasis)
What are two less common oral manifestations of PUD affecting the lips and teeth?
- vascular malformations of the lip typically occur in older men with PUD
- perimylolysis (enamel erosion) as a result of persistent regurgitation
Cimetidine and ranitidine may have a toxic effect on bone marrow. What are three ways in which this can manifest in the oral cavity?
- mucosal ulcerations (agranulocytosis)
- mucosal pallor (anemia)
- bleeding or petechiae (thrombocytopenia)
Xerostomia has been associated with the use of famotidine. What are the dental implications of dry mouth?
A chronic dry mouth renders the patient susceptible to bacterial infection (caries) and fungal disease (candidiasis).
Inflammatory bowel disease (IBD) is a term encompassing two idiopathic diseases of the GI tract. What are they?
- ulcerative colitis
- Crohn disease
Which form of IBD is a mucosal disease that is limited to the large intestine and rectum?
Which form of IBD is a transmural disease that may produce “patchy” ulcerations at any point along the alimentary canal?
Environment factors also are contributory to risk for IBD. How does smoking affect risk for IBD?
Smoking increases risk for Crohn disease, but decreases risk for ulcerative colitis
Numerous genetic susceptibility genes have been identified for IBD. What are five?
- IL-23 receptor gene
- TNFSF15 gene
- TLR-4 gene
What is the underlying cause of both ulcerative colitis and Crohn disease?
A dysregulated innate immune response to commensal bacteria that triggers T cells and antibodies.
What are histopathologic findings of ulcerative colitis? (4)
- epithelial necrosis
- distorted cryptic architecture
- pseudopolyp formation
- submucosal fibrosis
Ulcerative colitis usually is a lifelong disease. What are two long-term complications of ulcerative colitis?
- toxic megacolon
- carcinoma of the colon
Toxic megacolon is a long-term complication of ulcerative colitis. What can megacolon lead to?
The colon dilates because of weakening of the wall, and intestinal perforation then becomes likely.
What is the most common portion of the bowel involved in Crohn disease?
Although any portion of the bowel may be involved, the distal ileum and the proximal colon are affected most frequently.
What are histopathologic findings of Crohn disease? (4)
- transmural involvement
- segmental distribution (“skip lesions”)
- nodular “cobblestone” mucosa
- epithelioid granulomas
What three prominent symptoms are experienced by patients with ulcerative colitis?
- attacks of diarrhea
- rectal bleeding (or bloody diarrhea)
- abdominal cramps
What three prominent symptoms are experienced by patients with Crohn disease?
- diarrhea (often without blood)
- abdominal pain in the right lower quadrant
- anorexia and weight loss
Symptoms in Crohn disease vary according to the site and extent of involved tissue. What are the three major patterns of tissue involvement?
- disease of the ileum and cecum
- disease confined to the small intestine
- disease confined to the colon
What complication of Crohn disease can result in weight loss, growth failure, anemia, and clubbing of the fingers?
What are four laboratory findings of IBD?
- anemia (due to nutrient deficiencies)
- ↓ total protein and albumin (malnutrition)
- inflammatory activity (↑ ERS, CRP)
- ↑ platelet or leukocyte counts
Antibodies against which yeast can be useful in differentiating Crohn disease from ulcerative colitis?
Antibodies against Saccharomyces cerevisiae are elevated in 40 to 70% of patients with Crohn disease, but in fewer than 15% of those with ulcerative colitis.
Ulcerative colitis and Crohn disease can be managed by drugs but not cured. What are the "first-line" drugs for these conditions?
- antiinflammatories (e.g. mesalamine)
Ulcerative colitis and Crohn disease can be managed by drugs but not cured. What are the "second-line" drugs for these conditions?
- immunosuppressive agents
Ulcerative colitis and Crohn disease can be managed by drugs but not cured. What is a "third-line" drug for management of Crohn disease?
monoclonal antibodies (e.g. infliximab)
What is the mechanism of action of the following drugs?
They are covalently bound to 5-aminosalicylic acid (5-ASA) which is released by colonic bacteria, delivering local antiinflammatory effects within the intestine.
What is a significant concern of the use of 5-ASA drugs which requires physician monitoring?
What drugs are often are combined with sulfasalazine to induce remission in patients with IBD who are experiencing flare-ups?
What drugs used in patients with who have active IBD that is unresponsive to corticosteroids?
What are three immunomodulator drugs used to treat IBD?
What is the limits the use of immunomodulator drugs in the treatment of IBD?
Their use is limited by their toxicity; WBC count and LFTs must be monitored routinely.
What drugs are reserved for severe IBD that is refractory to other drugs and for maintenance of remission?
anti-TNF monoclonal antibodies
What are three anti-TNF monoclonal antibodies used to treat IBD?
Can patients with IBD recieve denal care?
Patients with mild disease can receive dental care; patients with moderate to severe disease are poor candidates for dental care and should be referred.
Patients with mild IBD can receive dental care. What are four indications of mild disease?
- <4 BMs per day with little or no blood
- no fever
- few symptoms
- ESR <20 mm/hr
Patients with moderate to severe IBD are poor candidates for dental care. What are four indications of moderate to severe disease?
- >6 BMs per day with blood
- ESR >30 mm/hr
What tests must be obtained for patients with IBD who take sulfasalazine prior to elective surgical procedures?
These patients may be at risk for thrombocytopenia, and require a complete blood count and bleeding time.
What is a clinical concern of the use of a steroid drug by a patient with IBD?
Corticosteroids can suppress adrenal function and reduce the ability of the patient to withstand stress.
What is the recommendation for patients taking corticosteroids to avoid adrenal ansufficiency?
The patient take the usual daily dose of corticosteroids before the dental appointment.
What mildly painful oral lesions may affect the alveolar, labial, and buccal mucosa in patients with IBD?
What form of stomatitis occurs in patients with ulcerative colitis?
What oral manifestation of Crohn disease involves diffuse swelling of the lips and cheeks?
What severe form of colitis that results from the bacterial overgrowth in the large colon?
What five risk factors for pseudomembranous colitis?
- antibiotic use
- older patients
- hospitalized patients
- patients receiving tube feeding
- immunocompromised patients
What is the causative agent in 90% to 99% of pseudomembranous colitis cases?
What type of bacteria is C. difficile?
It is a gram-positive, spore-forming anaerobic rod that has been found in sand, soil, and feces.
What three antibiotics are associated with the highest risk for pseudomembranous colitis?
- clindamycin (2%–20%)
- ampicillin or amoxicillin (5%–9%)
- third-generation cephalosporins (<2%)
What are the histopathologic findings of pseudomembranous colitis? (4)
- epithelial necrosis
- distended goblet cells
- leukocyte infiltration of the lamina propria
- pseudomembranous plaques
What is the most common presenting manifestation of pseudomembranous colitis?
How soon after antibiotic administration does diarrhea caused by pseudomembranous colitis occur?
Diarrhea often begins within the first 4 to 10 days, but may develop 1 day to 8 weeks after drug administration.
What is the first-line treatment of pseudomembranous colitis? (3)
- discontinue the offending antimicrobial agent
- metronidazole 500 mg tid for 10–14 days, or
- vancomycin 125–500 mg qid for 10–14 days
Can patients with pseudomembranous colitis recieve dental care?
Elective dental care should be delayed until after pseudomembranous colitis has resolved.