INFECTION OF GASTROINTESTINAL TRACT

• Gastritis


  Inflammation of the mucosal lining of the stomach
• Enteritis


  Inflammation of the small intestines
• Colitis


  Inflammation of the colon (large intestines)
• Gastroenteritis


  Inflammation of the mucosal lining of the stomach and intestine
• Hepatitis


  Inflammation of the liver
• Dysentery


  Low volume, painful, bloody diarrhea
• The digestive system is inhabited by many microorganisms. From the mouth down to the colon, these different ecosystems are occupied by site specific microbial populations
• The stomach, due to its acidity, acts as an effective sterilization chamber that limits the entry of microorganisms to the small intestines
• Infections of the digestive system range from asymptomatic infections to life threatening loss of fluids and electrolytes, or severe ulceration accompanied by intestinal perforation and hemorrhage
• The clinical manifestations vary from one another
• Factors that play important roles in the causation of infectious disease in the digestive system

  • Intact mucosal epithelium covering all parts of the digestive system
  • Alteration of the acid barrier of the stomach
  • Changes in the composition of the normal flora
• Mechanisms by which signs and symptoms of infections in the gastrointestinal tract are produced

  1. Pharmacologic action

  2. Local inflammation

  3. Deep tissue invasion

  4. Perforation

  
• Dental caries (tooth decay)


  Accumulations of microorganisms and their products called dental plaques that are involved in the formation of dental caries

  
• Streptococcus mutans


  • The most important organism that causes dental caries

  
• Preventive measures against the development of dental caries include minimal ingestion of sucrose, brushing, and flossing, regular dental visits to remove plaque, and the use of fluoride</b>

  
• Periodontal disease


  Conditions characterized by inflammation and degeneration of structures that support the teeth

  
• Gingivitis


  • Reversible inflammation of the gingivae or gums, characterized by bleeding of the gums while brushing the teeth
• Periodontitis


  • Chronic gum disease that can cause bone destruction and tooth loss

  
• Acute necrotizing ulcerative gingivitis


  Also called Vincent's disease or trench mouth, a common serious infection of the mouth characterized by pain that prevents normal chewing and may be accompanied by bad breath or halitosis

  
• Oral thrush


  A condition consisting of white patches adherent to the oral mucosa that may occur on the tongue, lips, gums, or palate, caused by the fungus Candida albicans

  
• Mumps (epidemic parotitis)


  • A highly communicable disease characterized by painful inflammation of the salivary glands, caused by the mumps virus
• Transmission of mumps virus

  Via respiratory droplets
• Clinical findings of mumps

  • Fever, malaise, anorexia followed by tender swelling of the parotid glands and/or other salivary glands
• Complications of mumps include orchitis and meningitis
• Laboratory diagnosis of mumps


  Virus isolation from saliva, spinal fluid, or urine, or measurement of antibody titers

  
• Gastritis and peptic ulcer disease


  The major pathologies involving the stomach, which are inflammatory in nature
• Helicobacter pylori


  • The most common cause of chronic gastritis and peptic ulcers, with rapid motility and urease production as major virulence factors

  
• Transmission of Helicobacter pylori

  Ingestion and person-to-person transmission
• Clinical findings of gastritis and peptic ulcer disease

  • Recurrent pain in the upper abdomen, specifically around the epigastric area, which may be complicated by bleeding into the gastrointestinal tract

  
• Laboratory diagnosis of gastritis and peptic ulcer disease

  Gastric biopsy specimens for histologic examination, culture, and measurement of antibody levels specific for H. pylori

  
• Treatment of gastritis and peptic ulcer disease


  Triple therapy with proton pump inhibitor, macrolide, and amoxicillin
• Hepatitis


  Inflammation of the liver, which can be caused by bacteria, viruses, and parasites
• Causes of hepatitis


  • Hepatitis viruses
  • Cytomegalovirus
  • Epstein Barr virus
  • Herpes Simplex virus
  • Rubella virus
  • Enteroviruses
  • Dengue virus
  • Yellow Fever virus

  
• Clinical findings of hepatitis

  • Fever, anorexia, nausea, vomiting, and jaundice, with dark urine and pale feces

  
• Important clinical features of the Hepatitis viruses


  • Provided in Table 18.1

  
• Hepatitis A Virus (HAV)


  Causes infectious hepatitis, transmitted mainly by the fecal-oral route
• Hepatitis A Virus


  • Short incubation period, most patients asymptomatic, no chronic hepatitis or carrier state, no predisposition to liver cancer
• Diagnosis of Hepatitis A

  Detection of antibodies directed against the virus, with IgM indicating active infection and IgG indicating previous infection

  
• Treatment and prevention of Hepatitis A

  Supportive treatment, active immunization with inactivated vaccine, passive immunization with immune globulin after exposure
• Hepatitis B Virus (HBV)


  Causes serum hepatitis, transmitted through blood, sexual intercourse, and from mother to newborn