Ch 24 Digestive System Infections Flashcards
The digestive system structure is divided into what 2 groups?
Gastrointestinal Tract
Accessory Digestive Organs
The pathway from the mouth to the anus =
GI Tract
Organs involved in grinding food or providing digestive secretions =
Accessory Digestive Organs
The tongue, teeth, and salivary glands are all-
Accessory Digestive Organs
The liver, gallbladder, and pancreas are all-
Accessory Digestive Organs
The esophagus, stomach, and duodenum are all-
Almost free of any microbes
What prevents microbial colonization in the esophagus, stomach, and duodenum?
Peristalsis + the rapid transport of food
What’s the most prevalent microbe on the tongue, teeth, jejunum, ileum, colon, and rectum?
Species of Streptococci
The microbiota in the lower small intestine and colon are-
Microbial Antagonists
The microbial antagonists in the lower small intestine and colon do what for the body?
Protect the body by outcompeting pathogens.
Produce vitamins, folic acid, biotin, and vitamin K.
The mucous membrane does what for the body?
Prevents entry of microbes into the blood stream
Erosions of the linings of either the stomach or small intestine =
Peptic Ulcers
Ulcers that pierce the stomach or intestine are called-
Perforations
A Perforation can cause-
Shock
Abdominal pain is the main symptom of-
Peptic Ulcers
Signs and symptoms of Peptic Ulcers includes:
Abdominal Pain
Nausea
Vomiting (With or Without Blood)
Weight Loss
Burping
Loss of Appetite
Chest Pain
Black Tarlike Stools
Peptic Ulcers are caused by what bacteria?
Helicobacter pylori
How does H. pylori cause Peptic Ulcers?
It invades mucous, its toxins and inflammation cause the layer of mucous to become thin, gastric acid then destroys the epithelial tissue and underlying tissue (Causing an ulcer)
How many people develop Peptic Ulcers per year?
456,000
How much of the population is infected by Peptic Ulcers?
2 thirds of the population
What are some risk factors for Peptic Ulcers?
Aspirin, Ibuprofen, Excessive Alcohol Consumption, Smoking, Family History
What can worsen Ulcer symptoms?
Stress
How can you diagnose Peptic Ulcers?
X-ray to identify Ulcers
Presence of H. pylori in stool
Inflammation of stomach or intestines caused by bacteria =
Bacterial Gastroenteritis
Bacterial Gastroenteritis is associated with-
Contaminated food or water and poor living conditions/lack of sanitation
What are the manifestations of Bacterial Gastroenteritis?
Nausea + Vomiting + Abdominal Pain + Cramps + Malaise + Fever + Dehydration
Treatment of Bacterial Enteritis includes-
Fluid and electrolyte replacement
Most E. coli Gastroenteritis are-
Harmless, but others can cause severe diarrheal illnesses
How does E. coli Gastroenteritis spread?
Contaminated food/water, direct contact with animals/people
What are the risk groups for E. coli Gastroenteritis?
Elderly, Pregnant, Immunocompromised, and Travelers
What are some symptoms of Enterotoxigenic E. coli (ETEC)?
Causes Traveler’s Diarrhea (Common in less developed countries).
It is a relatively mild condition that is self-limiting.
What’s the most dangerous types of E. coli that can cause epidemics?
Enterohemorrhagic E. coli (EHEC)
Manifestations of EHEC are-
Bloody Diarrhea, Severe Cramping, No Fever
EHEC produces a toxin called-
Verotoxin
Verotoxin can cause-
Hemolytic Uremic Syndrome (HUS)
What is HUS?
A type of kidney failure
How can EHEC be diagnosed?
Presence of Verotoxin Genes
Salmonella enterica lives in-
The intestines of virtually all vertebrates, especially reptiles and are eliminated in feces
Can S. enterica be a part of the normal microbiome of some humans?
Yes
How many unique strains of Salmonella are there?
How many species?
2,100 Unique Strands
Just 1 Species (Salmonella enterica)
What strains of Salmonella can cause Salmonellosis?
Enteritidis and Typhimurium
How does Salmonella spread?
Via contaminated food (usually eggs and poultry) and water, direct animal contact, rarely person to person
How does Salmonellosis occur?
Salmonella passes through intestinal cells into the bloodstream where they are phagocytized.
Salmonella can survive phagocytosis, and therefore becomes disseminated throughout the body.
Disruption of the intestinal cells can cause-
Tissue damage and inflammation leading to fluid leakage and diarrhea
Symptoms of Salmonellosis develop within how long after infection?
6-4 Hours
Patients with Salmonellosis experience-
Fever + Headache + Muscle Pain + Loss of Appetite for a week or more
How do you diagnose Salmonellosis?
Finding Salmonella in stool
Symptoms of salmonellosis develop within how long after infection?
6 hours to 4 days
5-10 clear, watery, foul-smelling bowel movements per day =
Clostridium difficile (Antimicrobial-Associated) Diarrhea
What occurs during extreme cases of Clostridium difficile (Antimicrobial-Associated) Diarrhea?
Pseudomembranes colitis
Clostridium difficile is a part of the normal microbiome in the large intestine of what % of adults?
5%
What facilitates the growth of Clostridium difficile?
Antimicrobials
Clostridium difficile produces what 2 toxins?
Toxin A
Toxin B
What are the manifestations of Pseudomembranous colitis?
Life-threatening, involves inflammation, more than 10 bloody stools per day, and Pseudomembranes
What are Pseudomembranes?
(Lesions composed of connective tissue, dying leukocytes and dead colon cells).
What do the toxins produced by C. Diff mediate?
Inflammation + Pseudomembrane Formation
What does Toxin A do?
Breaks down junctions between colon cells triggering loss of fluid
What does Toxin B do?
Kills colon cells + Induces lesion formation
Any antibiotic can cause this disease and it is a byproduct of modern medicine =
C. Diff
What % of hospital pt’s carry C. Diff?
~20%
What are the risk groups for C. Diff?
Elderly, Burn Patients, Pt’s with Kidney Failure
Pt’s Recovering from Abdominal Surgery
Pt’s with History of Pseudomembranous colitis
How is C. Diff diagnosed?
Presence of bacterial toxin in stool or colonoscopy
How is C. Diff treated?
Antimicrobials + Experimental Fecal Transplants
Signs and symptoms of food poisoning:
Nausea + Vomiting + Diarrhea + Cramping
What is Bacterial Food Poisoning caused by?
Staphylococcus aureus
Diagnosis of Food Poisoning is-
Usually based on signs and symptoms
What is treatment of Food Poisoning like?
It usually passes on its own but it can be supported with F&E Replacement
What bacteria is responsible for food poisoning associated with raw or undercooked seafood?
Vibrio vulnificus
What % of people with food poisoning caused by V. vulnificus die?
1 in 5
When should you seek medical attention if you have food poisoning caused by undercooked seafood?
If it goes on for longer than 3 days
Vibrio vulnificus associated food poisoning is usually a mild disease that lasts about 3 days. What are the manifestations?
Watery Diarrhea, Cramps, Nausea, Fever, Vomiting
Treatment of V. vulnicans is-
Not usually necessary, but pt’s should drink plenty of fluids
Avoid eating undercooked shellfish or contact with salty or brackish water if you-
Have a wound
Why should you avoid eating undercooked shellfish or contact with salty or brackish water if you have a wound?
Wound infection can lead to Necrotizing Fasciitis
Diagnosis of V. vulnificus is based on-
Symptoms and whether patient has recently eaten raw or undercooked seafood.
Can also detect V. vulnificus in stool, wound, or blood
Macroscopic, multicellular worms =
Helminths
These can infect the GI Tract as Non-Disease-Causing Parasites =
Helminths
How many categories of Helminths are of importance to humans? What are they called?
Roundworms (Nematodes) + Flatworms (Platyhelminths)
Pinworm, Hookworm, Trichinella are all examples of-
Roundworms
Ancylostoma (fluke) + Taenia sp. (tapeworms) are both examples of-
Flatworms
What are the signs and symptoms of Tapeworm Infections?
Usually Asymptomatic
Nausea, Abdominal Pain, Weight Loss, & Diarrhea may occur
What are the different types of tapeworm?
Taenia saginata: Beef Tapeworm
Taenia solium: Pork Tapeworm
Diphyllobothrium latum: Fish Tapeworm
Tapeworms can be how long?
4-8 Meters
Where do Tapeworms develop into adults?
The Intestine
How are Tapeworms diagnosed?
Diagnosed by presence of proglottids in fecal sample
How are Tapeworms treated?
Antiparasitic Drugs
How do you prevent tapeworms?
Thoroughly cooking meat
Round worm that is ingested when eating undercooked, infected meat such as pork, boar or bear =
Trichinosis
Signs and Symptoms of Trichinosis begin how many days after ingesting the undercooked meat?
1-2 Days
What are Signs and Symptoms of Trichinosis?
Abdominal symptoms like diarrhea, pain and flu-like symptoms
Is Trichinosis fatal?
Rarely
Antiparasitic drugs available to kill adult worms, but-
killing larvae in tissue is difficult
How do you diagnose Trichinosis?
Usually based on symptoms, history, and looking for antibodies against the parasite
Are pinworms only transmitted among humans?
Yes
What are the manifestations of Pinworm Infestation?
Perianal itching, irritability, and decreased appetite
One-third of cases are asymptomatic
What are Pinworm Infections caused by?
Enterobius vermicularis
How is Pinworm spread?
Females deposit eggs in the perianal region at night
Eggs can be dislodged and spread the disease
As many as one-third of American children are affected by-
Pinworm Infestation
What are the manifestations of Viral Gastroenteritis
Similar to those of bacterial gastroenteritis
Diarrhea, vomiting, stomach cramps, fever
Dehydration is common complication
How long do Viral Gastroenteritis infections last?
3-8 Days
What is Viral Gastroenteritis caused by?
Caliciviruses, Astroviruses, Rotaviruses
What causes 90% of nonbacterial gastroenteritis?
Noroviruses
Viral Gastroenteritis is common in confined places such as-
Cruise Ships
Does a vaccine for rotavirus exist?
Yes
How do you diagnose a Rotavirus Infection?
Serological test distinguishes among viruses
Treatment of Rotavirus Infection involves-
F&E Replacement
Rotaviruses are an important cause of-
Childhood deaths in developing countries
That are the manifestations of Viral Hepatitis?
Jaundice, abdominal pain, fatigue, vomiting, and weight loss
Symptoms may occur years after initial infection
Hepatitis is a general term meaning-
Inflammation of the liver
Viral Hepatitis generally has long incubation periods ranging from-
~15 to 120 Days
Transmitted in feces-contaminated food or water
Patients release virions in feces and are infective even without developing symptoms
“Infectious hepatitis” is usually mild and 99% recover fully =
Hepatitis A Virus (HAV)
Parenteral transmission, crosses placenta, exposure to infectious blood or body fluids like semen and saliva =
Hepatitis B Virus (HBV)
Parenteral transmission, IV drug use =
Hepatitis C Virus (HCV)
Parenteral transmission (contact with infected blood).
Uncommon in US, requires the person to already be infected with HBV so that it can replicate =
Hepatitis Delta Virus (HDV)
Transmitted by feces-contaminated drinking water. Not common in the US =
Hepatitis E Virus (HEV)
A common name for the Hepatitis E Virus is-
Enteric Hepatitis
Note that HBV, HCV, and HDV are enveloped viruses, but HAV and HEV are-
Naked Viruses
Initial diagnosis of Viral Hepatitis is made by-
Observation of jaundice, enlarged liver, or fluid in the abdomen
Aside from observing for jaundice, enlarged liver, and fluid in the abdomen, what other things can be done to diagnose Viral Hepatitis?
General lab testing to assess liver function
Serological testing can identify viral antigens
HBV diagnosed by viral proteins in body fluids
What can be done to give supportive care for someone with Viral Hepatitis?
Antivirals available to help reduce viral load
How can Viral Hepatitis be prevented?
Prevented with good hygiene and protected sex or abstinence
Vaccines are available against HAV and HBV
HAV vaccine is also protective against HEV
HBV vaccine is also protective against HDV
