Gastrointestinal Tract Quiz

Gastrointestinal Tract

The gastrointestinal tract includes the esophagus, stomach, small intestines (duodenum, jejunum, ileum), large intestines (cecum, colon, rectum), and anus.
Inflammation of the stomach is known as gastritis.
Inflammation of the stomach and intestines is called gastroenteritis.
Inflammation of the small and large intestines is enterocolitis.
Diarrhea is an abnormal increase in bowel movements, ranging from loose to liquid stool.
Dysentery is diarrhea with cramping abdominal pain.
Proctitis is inflammation of the rectal mucosa.
80% of fecal dry weight is bacteria.
Normal flora prevents colonization by pathogens.
Common bacteria of the normal flora include anaerobic bacilli (Bacteroides spp.), GN enteric bacilli, Enterococci, Streptococci, and S. aureus.
Yeast (Candida) is also a part of normal flora.
Non-inflammatory diarrhea is caused by bacterial toxins or enterotoxins, resulting in watery stool without fever or other symptoms.
Non-inflammatory diarrhea can be caused by Vibrio cholerae, Enterotoxigenic E. coli, Bacteroides, viruses (Giardia lamblia, Cyclospora, Cryptosporidium).
Inflammatory diarrhea involves organisms invading the intestinal mucosa, destroying cells, and producing symptoms like fever and loose, small-volume stool.
Inflammatory diarrhea may contain PMNs, blood, and mucous.
Common causes of inflammatory diarrhea include Salmonella spp., Shigella spp., Y. enterocolitica, Campylobacter spp., Enteroinvasive E. coli, and Clostridium difficile.
Enterotoxins in food can cause rapid-onset diarrhea (less than 12 hours).
Examples of this include food containing Enterotoxigenic E. coli, V. cholerae, S. aureus, C. perfringens, and B. cereus toxins.
Common diarrheal diseases include Salmonella (gastroenteritis), Shigella (bacillary dysentery), Y. enterocolitica (enterocolitis), Campylobacter jejuni and C. coli, E. tarda, Vibrio parahaemolyticus, plesiomonas shigelloides, Edwardsiella tarda, and Listeria monocytogenes (gastroenteritis).
The intestinal parasites that cause diarrhea include Giardia, Entamoeba, Cryptosporidium, Cyclospora, and Microsporidia.
Viruses that cause diarrhea include Rotavirus, adenovirus, calcivirus, and astrovirus.
Other diseases involving the gastrointestinal tract include H. pylori (chronic gastritis, peptic and duodenal ulcers), C. difficile (antibiotic-associated diarrhea, pseudomembranous colitis), C. perfringens (enterotoxin).
Another disease is Mycobacterium avium (GI diseases in AIDS patients).
E. coli (O157:H7) causes hemorrhagic colitis and hemolytic uremic syndrome (HUS).
Other E. coli types include enterohemorrhagic, enteroinvasive, enterotoxigenic, enteropathogenic (enteroadherent), and enteroaggregative strains.
Methods for transmission of GI infections include fecal-oral route, direct person-to-person contact, and animal contact. Infectious organisms may need to survive the stomach's acidic environment.

Respiratory Tract

Upper Respiratory Tract (URT) infections affect the oral cavity, nose, mouth, throat, epiglottis, and larynx.
Lower Respiratory Tract (LRT) infections affect trachea, bronchi, bronchioles, and lung alveoli.
The LRT below the larynx is normally sterile.
Normal flora of the URT includes staphylococci (including S. aureus), streptococci (including viridans and pneumococci), Micrococcus spp., diphtheroids, Neisseria, Haemophilus, anaerobes, and spirochetes, Candida spp.
Common URT infections include thrush, laryngitis, epiglottitis, pharyngitis, tonsillitis, sinusitis, otitis media, Diphtheria, Pertussis(whooping cough).
Respiratory viruses that occur as URT pathogens include influenza, parainfluenza, RSV, adenovirus, rhinovirus, coronavirus, coxsackie A, EBV, and CMV.
Other URT pathogens include S. pyogenes, B-hemolytic strep groups C, F, and G, and Arcanobacterium haemolyticum.
Other URT pathogens include H. influenzae, N. gonorrhoeae, Corynebacterium diphtheriae, Bordetella pertussis, and parapertussis.
Common LRT pathogens include S. pneumoniae, H. influenzae, M. catarrhalis, M. pneumoniae, Chlamydia spp.
Other LRT pathogens, including but not limited to, GNR (gram-negative rods), S. aureus, Legionella spp. anaerobes, Mycobacteria, and fungi, sometimes affect individuals with compromised immune systems.
Common types of community-acquired pneumonia include S. pneumoniae, Mycoplasma pneumoniae, H. influenzae, and M. catarrhalis.
Hospital-acquired pneumonia is often seen in patients who have a ventilator, and pathogens can include Enterobacteriaceae, K. pneumoniae, S. marcescens, S. aureus, NFGNR, P. aeruginosa, Burkholderia cepacia, S. pneumoniae, and anaerobic bacteria.
Other miscellaneous agents include Mycobacteria, Legionella, Chlamydia, C. trachomatis, C. pneumoniae.
Emerging viral RT infections include avian influenza H5N1, H1N1, SARS, and coronavirus.
Bioterrorism agents causing respiratory infections include B. anthracis, Y. pestis, Coxiella burnetii, and F. tularensis.
Routes of infection include inhalation of aerosols, hematogenous spread (bloodstream), aspiration of oropharyngeal secretions, and the possibility of contaminations.
Specimen collection for respiratory infections includes, but is not limited to, sputum (expectorated, induced, and invasive), nasal swabs, tracheal aspirates, bronchial washings, brushings, biopsies, pleural fluid aspirates, and Tympanocentesis(middle ear fluid).
Sputum cultures and collection require special consideration of possible contaminations with normal flora (NF).
Microscopic analysis is carried out on the collected specimens (gram stains). This analyzes for presence of pathogens.
Cultures include processing on BAP, CHOC, MAC culture media.
Special media is required for CF patients (containing B. cepacia, MRSA, and Pseudomonas species).
Anaerobic cultures are also possible.