Lecture 19 Flashcards
Function of the Gastrointestinal Tract
Digestion and absorption of food, reabsorption of water and Elimination of wastes
What is the Gastrointestinal tract composed of?
Oral cavity Esophagus, stomach, small and large intestines, rectum (mouth to anus)
Diagnosis of Gastrointestinal Diseases
Fecal analysis (culture, blood), Endoscopic procedures, Radiologic examination (X ray/CT), and MRI/ultrasound
Cleft Lip and Cleft Palate
Maldevelopment leads to defects. Seen in 1 per 1,000 births, Multifactorial inheritance pattern, Upper lip and jaw (cleft lip), Palate (cleft palate). Can lead to liquid aspiration, airway obstruction, feeding difficulties
When and how is Cleft Lip and Cleft Palate fixed
Surgical correction (cheiloplasty)
Cleft lip: Soon after birth
Cleft palate: 1 to 2 years of age with speech therapy to correct nasal speech
How many temporary and permanent teeth do we have?
Temporary or deciduous teeth (20 teeth) formed before birth and emerge in childhood
Permanent teeth (32 teeth) develop in childhood and push on roots to replace temporary set
What antibiotic causes permanent yellow-gray to brown discoloration of the crown of teeth when administered during enamel formation?
Tetracycline
Disease of oral cavity
Diverse collection of aerobic and anaerobic bacteria that mix with saliva, forming sticky biofilm on teeth (dental plaque)
Disease of dental cavity
Loss of tooth structure (decay) from bacterial action (acidic erosion of enamel and decay of dentin (decreased density, softening and discoloration of teeth)
Role of Saliva
Saliva has protective role – prevents dry mouth (xerostoma) have increased risk of cavity development
Gingivitis
Inflammation of the gums due to masses of bacteria and debris accumulating around base of teeth – can lead to periodontal disease
Stomatitis
Inflammation of the oral cavity
Cause of Inflammation of the Oral Cavity
Irritants: Alcohol, tobacco, hot or spicy foods
Infectious agents: Herpesvirus(HSV), HPV, Candida albicans (fungus), bacteria that cause trench mouth – advanced form of gum disease (bleeding, swelling, pain, ulcers)
Canker sores: small painful superficial ulcer of oral mucosa with inflammatory border (red) painful – not contagious
Leukoplakia (Carcinoma of the Oral Cavity)
White lesions - rarely indicate possible dysplasia (20%)
Erythroplakia (Carcinoma of the Oral Cavity)
Depressed red lesions frequently associated with dysplasia and carcinoma
What is so dangerous about oral cancers?
Oral cancers readily metastasize – many nearby LN in head and neck; HPV (serotype 16) – responsible for 75% of head/neck cancers (slow progression – decades)
Esophagus
Muscular tube that extends from pharynx to stomach with sphincters at upper (relaxes to allow passage of swallowed food) and lower (relaxes to allow passage of food to the stomach) ends
Esophageal sphincter dysfunction symptoms
Difficulty swallowing (dysphagia), Substernal discomfort or pain (heartburn-GERD), Inability to swallow (aphagia - complete obstruction), and Regurgitation of food or fluids into trachea causing aspiration, choking and coughing
What does Esophageal sphincter dysfunction cause?
Failure of the cardiac (gastroesophageal) sphincter to function properly, Tears in lining of the esophagus from retching and vomiting from repetitive, intermittent, vigorous contractions that increase intra-abdominal pressure, and Esophageal obstruction from carcinoma, food impaction, or stricture (esophageal webs, rings)
Two major types of disturbances of cardiac sphincter (lower esophageal sphincter-LES)
- Achalasia: Sphincter fails to open properly due to malfunction of nerve plexus; esophagus becomes dilated proximal to constricted sphincter from food retention (inability to swallow)
- Incompetent cardiac sphincter: Sphincter remains open; gastric juices leak back into esophagus (GERD)
Reflux esophagitis
Irritation, Inflammation – Asthma risk
Barrett esophagus
Glandular metaplasia; change from squamous to columnar epithelium - increases risk for cancer
Treatment for cardiac LES dysfunction
Lifestyle modification, diet (alcohol), antacids
Drugs – reduce acid production in stomach (proton pump inhibitors -PPI)
Surgery – if hiatal hernia/esophageal rings
Causes of Esophageal obstruction
Carcinoma (narrows esophagus), Barretts esophagus, Food impaction: improperly chewed food, Stricture (from scar tissue), Hiatal hernia, and esophageal rings
Mallory Weiss syndrome
Caused by retching and vomiting – often related to excess alcohol intake or repeated forced vomiting (Bulimia); tears in the mucosa or lining of esophagus (blood loss)
Heals on its own; may need surgery in repair in severe case
Boerhaave syndrome + treatment
Rupture of esophagus / full thickness perforation – high mortality with treatment (30%) always fatal without surgery and antibiotic Tx
Acute Gastritis
Inflammation of the gastric lining, self-limited inflammation of short duration. Caused by nonsteroidal anti-inflammatory drugs (NSAIDs) that inhibit cyclooxygenase (COX) enzyme: Aspirin, ibuprofen, naproxen and Alcohol (gastric irritant)
COX-1
Promotes synthesis of prostaglandin that protects gastric mucosa
COX-2
Promotes synthesis of prostaglandin that mediates inflammation
Helicobacter pylori Gastritis
Small, gram-negative organisms that colonize the surface of gastric mucosa. They grow within layer of mucus covering epithelial cells lining the stomach. Common infection that increases with age (50% by age 50) – not all are symptomatic. Spreads from person-to-person through close contact and fecal–oral route