Digestive copy - Copy

Gastrointestinal System Diseases Overview

  • Chapter 22 covers various diseases affecting the gastrointestinal system, including dental issues, food poisonings, viral and protozoan infections, and bacterial infections of the stomach, esophagus, and intestines.

Dental Issues

Dental Plaque

  • Continuous coating of microorganisms and organic matter on tooth surfaces.

  • First step in tooth decay and gum disease.

  • Formation begins within 24 hours post-cleaning.

  • Positively charged proteins in saliva attach to negatively charged enamel (pellicle).

  • Key bacteria involved: Streptococcus mutans and Streptococcus sanguis.

Dental Caries (Tooth Decay)

  • Definition: Chemical dissolution of enamel and deeper tooth structures.

  • Most common infectious disease in developing regions due to diet high in refined sugar.

  • Can progress through enamel to dentin and pulp cavity, leading to abscess formation.

  • Major cause: Streptococcus mutans; also Lactobacillus and Actinomyces viscosus.

Prevention of Dental Caries

  • Use of fluoride to reduce tooth solubility.

  • Limiting dietary sucrose intake.

  • Application of fissure sealants.

Periodontal Disease

  • Chronic, painless infection affecting over 80% of individuals.

  • Major cause of tooth loss, involves gum inflammation and erosion of supporting structures.

Types

  • Gingivitis: Mild form affecting only the gums.

  • Acute necrotizing ulcerative gingivitis: Severe form, known as trench mouth.

  • Periodontitis: Advanced stage affecting bones and tissues supporting teeth.

Food Poisonings

General Information

  • 76 million cases of foodborne diseases annually in the U.S., mostly mild.

  • Over 250 different foodborne diseases identified, caused by bacteria, viruses, and parasites.

  • Types of foodborne diseases:

    • Intoxications: Result from toxins.

    • Infections: Require microbial multiplication in the host.

Staphylococcal Food Poisoning

  • Caused by Staphylococcus aureus, produces heat-stable enterotoxins.

  • Common sources: Custard, cream-filled foods, poultry, and meats.

  • Symptoms arise within 1-6 hours, including gastroenteritis, nausea, and diarrhea.

E. coli O157:H7

  • Reservoir: Cattle.

  • Symptoms: Severe bloody diarrhea, cramps, potential complications like kidney failure (3%-5% of cases).

Salmonellosis

  • Caused by Salmonella in animals and transmitted via contaminated foods.

  • Symptoms include fever, diarrhea, and abdominal cramps; can cause serious infections in immunocompromised individuals.

Prevention of Foodborne Illness

  • Cook foods thoroughly and prevent cross-contamination.

  • Wash hands and produce; timely refrigeration of leftovers is crucial.

  • Report suspected cases to health departments.

Shigellosis (Bacillary Dysentery)

  • Caused by several Shigella serotypes.

  • Mostly spread through contaminated food and contact with infected individuals.

  • Symptoms: Fever, abdominal cramps, diarrhea, can be self-limiting.

Cholera

  • A severe diarrheal illness caused by Vibrio cholerae.

  • Transmitted via contaminated water/food; presents with watery diarrhea, dehydration, and skin wrinkling.

  • Treatment: Fluid and electrolyte replacement; antibiotics can reduce severity.

Bacterial Infections of the Stomach & Intestines

Helicobacter pylori

  • First identified in 1982, it can survive stomach acidity by producing ammonia.

  • Presence associated with duodenal and gastric ulcers.

Treatment

  • Standard treatment includes tetracycline and amoxicillin.

Aflatoxin Poisoning

  • Caused by Aspergillus flavus, leading to liver damage.

  • Associated with agricultural crops (corn, peanuts).

Ergotism

  • Caused by Claviceps purpurea, found in cereals and grasses.

  • Symptoms: In both animals and humans, can include hyperexcitability and loss of coordination.

Thrush (Oropharyngeal Candidiasis)

  • Caused by yeast overgrowth due to various factors including immunocompromised states.

  • Diagnosis: Swab infected tissue; Treatment: Antifungal medications (fluconazole, clotrimazole).

Viral Diseases

Mumps

  • An acute viral illness caused by the mumps virus.

  • It primarily affects the salivary glands and is preventable via the MMR vaccine.

Viral Enteritis

  • Major cause of infant morbidity in developing countries, often linked to rotavirus.

  • Transmission occurs via the fecal-oral route.

Hepatitis

  • Inflammation of the liver from viruses or toxins, characterized by jaundice and other systemic symptoms.

  • Types: A, B, C, D, E with varying transmission methods, incubation periods, and severity.

Protozoan GI Diseases

Giardiasis

  • Caused by Giardia lamblia, transmitted through contaminated water or food.

  • Symptoms: Diarrhea, weight loss, and absorption issues.

Amoebic Dysentery

  • Caused by Entamoeba histolytica, leading to symptoms ranging from mild stomach pain to severe bloody diarrhea.

Cryptosporidosis

  • Often severe in AIDS patients, caused by Cryptosporidium parvum.

  • Symptoms: Watery diarrhea and other gastrointestinal issues.