Diarrheagenic Escherichia coli are a diverse group of E. coli that are classified into 5 major pathotypes which can cause intestinal infection and diarrhea.Transmission occurs primarily via consuming contaminated food or water, contact with infected people or animals, and swimming in untreated water. Pathogenesis varies based on the strain, but it can include toxin production, invasion of the mucosal surface, and adhesionAdhesionThe process whereby platelets adhere to something other than platelets, e.g., collagen; basement membrane; microfibrils; or other 'foreign' surfaces.Coagulation Studies with alteration of enterocyte structure. Noninvasive disease tends to present with watery diarrheaWatery diarrheaRotavirus, while invasive infectionsInfectionsInvasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases.Chronic Granulomatous Disease cause bloody diarrheaBloody diarrheaDiarrhea. The diagnosis can be established with PCRPCRPolymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules.Polymerase Chain Reaction (PCR). Management generally consists of supportive therapy (fluids and electrolytesElectrolytesElectrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions.Electrolytes). Antibiotics are reserved for severe or persistent infectionsInfectionsInvasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases.Chronic Granulomatous Disease and are contraindicated with enterohemorrhagic E. coli because of the risk of hemolytic uremic syndromeHemolytic uremic syndromeA syndrome that is associated with microvascular diseases of the kidney, such as renal cortical necrosis. It is characterized by hemolytic anemia; thrombocytopenia; and acute renal failure.Hypocoagulable Conditions.
Escherichia coliEscherichia coliThe gram-negative bacterium Escherichia coli is a key component of the human gut microbiota. Most strains of E. coli are avirulent, but occasionally they escape the GI tract, infecting the urinary tract and other sites. Less common strains of E. coli are able to cause disease within the GI tract, most commonly presenting as abdominal pain and diarrhea. Escherichia coli is a gram-negative bacillusBacillusBacillus are aerobic, spore-forming, gram-positive bacilli. Two pathogenic species are Bacillus anthracis (B. anthracis) and B. cereus. Bacillus bacterium.
Family: EnterobacteriaceaeEnterobacteriaceaeA family of gram-negative, facultatively anaerobic, rod-shaped bacteria that do not form endospores. Its organisms are distributed worldwide with some being saprophytes and others being plant and animal parasites. Many species are of considerable economic importance due to their pathogenic effects on agriculture and livestock.Cephalosporins
Scanning electron microscope image of enterotoxigenic Escherichia coli
Image: “Under an extremely high magnification of 44, 818X, twice that of PHIL 10574 and 10575, this scanning electron microscopic (SEM) image revealed some of the morphologic details displayed by a single Gram-negative, rod-shaped, Escherichia coli bacterium.” by Janice Haney Carr. License: Public Domain
Pathogenic strains of E. coli
Diarrheagenic strains of E. coli can be classified into 5 key “pathotypes,” each of which has unique virulence factorsVirulence factorsThose components of an organism that determine its capacity to cause disease but are not required for its viability per se. Two classes have been characterized: toxins, biological and surface adhesion molecules that affect the ability of the microorganism to invade and colonize a host.Haemophilus and pathologic mechanisms.
Enterohemorrhagic E. coli (EHEC)/Shiga toxin-producing E. coli (STEC)
Transmission
Fecal–oral route
Contaminated meat or produce (E. coli serotype O157:H7 and other STEC have a bovine reservoirReservoirAnimate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (disease vectors) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks. Humans may serve both as disease reservoirs and carriers.Escherichia coli)
Contaminated water
Table: Comparison of E. coli strains
Pathogen
Invasive?
Toxin?
Type of diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea
CytotoxinsCytotoxinsSubstances that are toxic to cells; they may be involved in immunity or may be contained in venoms. These are distinguished from cytostatic agents in degree of effect. Some of them are used as cytotoxic antibiotics. The mechanism of action of many of these are as alkylating agents or mitosis modulators.Helicobacter
Inflammatory
Bloody
EHEC
Yes
Shiga toxin
Inflammatory
Bloody
LT: heat-labile enterotoxin
ST: heat-stable enterotoxin
ETEC: Enterotoxigenic E. coli
EPEC: Enteropathogenic E. coli
EAEC: Enteroaggregative E. coli
EIEC: Enteroinvasive E. coli
EHEC: Enterohemorrhagic E. coli
Most common cause of traveler’s diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea
> 200 million cases/year
Pathophysiology
Enterotoxigenic E. coli is a noninvasive pathogen. It uses fimbrial adhesins to bindBINDHyperbilirubinemia of the Newborn enterocytes in the small intestineSmall intestineThe small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy and produces the following enterotoxins:
↑ ChlorideChlorideInorganic compounds derived from hydrochloric acid that contain the Cl- ion.ElectrolytessecretionSecretionCoagulation Studies and ↓ NaCl absorptionAbsorptionAbsorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation.Digestion and Absorption → water efflux into the intestinal lumen → watery diarrheaWatery diarrheaRotavirus
Activates adenylate cyclase → ↑ intracellular cAMPcAMPAn adenine nucleotide containing one phosphate group which is esterified to both the 3′- and 5′-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and acth.Phosphodiesterase Inhibitors
↑ ChlorideChlorideInorganic compounds derived from hydrochloric acid that contain the Cl- ion.ElectrolytessecretionSecretionCoagulation Studies and ↓ NaCl absorptionAbsorptionAbsorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation.Digestion and Absorption → water efflux into the intestinal lumen → watery diarrheaWatery diarrheaRotavirus
Similar to choleraCholeraAn acute diarrheal disease endemic in india and southeast Asia whose causative agent is Vibrio cholerae. This condition can lead to severe dehydration in a matter of hours unless quickly treated.Vibrio toxin (less severe)
Enterotoxigenic Escherichia coli (ETEC) pathogenesis: ETEC attaches to enterocytes via colonization factor antigen (CFA; fimbrial adhesin). The heat-stable (ST) enterotoxin causes cyclic guanosine monophosphate (cGMP) accumulation in cells and secretion of fluid and electrolytes into the intestinal lumen. The heat-labile (LT) enterotoxin acts like cholera toxin, which increases cyclic adenosine monophosphate (cAMP) by activating adenylyl cyclase (AC). The general effect is water and chloride hypersecretion and inhibited sodium reabsorption. Noninvasive enterotoxins remain within the intestinal lumen and do not invade the epithelial cells. GC: guanylyl cyclase LTA: A subunit of the heat-labile enterotoxin
Image by Lecturio.
Clinical presentation
Time course:
IncubationIncubationThe amount time between exposure to an infectious agent and becoming symptomatic.Rabies Virus period: 1–3 days
Symptom duration: 1–5 days
Clinical characteristics:
Acute secretory diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea:
NauseaNauseaAn unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses.Antiemetics (vomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia is less common)
Diagnosis
This disease is self-limited; therefore, a diagnostic workup is not usually needed. However, ETEC can be diagnosed by identifying LT or ST genesGenesA category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.DNA Types and Structure on PCRPCRPolymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules.Polymerase Chain Reaction (PCR) for individuals with severe disease.
Antimotility agents (e.g., loperamideLoperamideOne of the long-acting synthetic antidiarrheals; it is not significantly absorbed from the gut, and has no effect on the adrenergic system or central nervous system, but may antagonize histamine and interfere with acetylcholine release locally.Antidiarrheal Drugs)
Antibiotics are generally not required for most cases because of the disease’s self-limited nature.
Enteropathogenic E. coli
Epidemiology
A common cause of diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea in infants or young children (< 2 years of age)
Most common in resource-limited areas
Pathophysiology
Bundle-forming pilus: necessary for attaching to intestinal cells
Altered water and electrolyte secretionSecretionCoagulation Studies and absorptionAbsorptionAbsorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation.Digestion and Absorption
Enteropathogenic Escherichia coli (EPEC) pathogenesis: EPEC uses intimin adhesion molecules to adhere to the intestinal cells. Binding causes cell deformation (brush border degeneration and loss of microvilli). The characteristic effect of attachment and effacement is thought to be the primary cause of diarrhea.
NauseaNauseaAn unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses.Antiemetics and vomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia
MalnutritionMalnutritionMalnutrition is a clinical state caused by an imbalance or deficiency of calories and/or micronutrients and macronutrients. The 2 main manifestations of acute severe malnutrition are marasmus (total caloric insufficiency) and kwashiorkor (protein malnutrition with characteristic edema).Malnutrition in children in resource-limited countries is a potential complication of persistent diarrheaPersistent DiarrheaEntamoeba spp./Amebiasis.
Diagnosis
Enteropathogenic E. coli can be diagnosed by identifying specific genesGenesA category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.DNA Types and Structure using PCRPCRPolymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules.Polymerase Chain Reaction (PCR).
Management
Supportive therapy
Most individuals do not require antibiotic therapy.
ImmunocompromisedimmunocompromisedA human or animal whose immunologic mechanism is deficient because of an immunodeficiency disorder or other disease or as the result of the administration of immunosuppressive drugs or radiation.Gastroenteritis individuals (e.g., those with HIVHIVAnti-HIV Drugs/AIDSAIDSChronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS)
Pathophysiology
Aggregative adherence fimbriaeAggregative adherence fimbriaeEscherichia coli (AAFAAFEscherichia coli) help bacteriaBacteriaBacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology adhere to intestinal mucosaIntestinal MucosaLining of the intestines, consisting of an inner epithelium, a middle lamina propria, and an outer muscularis mucosae. In the small intestine, the mucosa is characterized by a series of folds and abundance of absorptive cells (enterocytes) with microvilli.Small Intestine: Anatomy.
AggregationAggregationThe attachment of platelets to one another. This clumping together can be induced by a number of agents (e.g., thrombin; collagen) and is part of the mechanism leading to the formation of a thrombus.Coagulation Studies of bacteriaBacteriaBacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology → forms a biofilmBiofilmEncrustations formed from microbes (bacteria, algae, fungi, plankton, or protozoa) embedded in an extracellular polymeric substance matrix that is secreted by the microbes. They occur on body surfaces such as teeth (dental deposits); inanimate objects, and bodies of water. Biofilms are prevented from forming by treating surfaces with dentifrices; disinfectants; anti-infective agents; and anti-fouling agents.Staphylococcus
FeverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
VomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia
Diagnosis
The diagnosis of EAECEAECEscherichia coli can be made by identifying specific genesGenesA category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.DNA Types and Structure using PCRPCRPolymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules.Polymerase Chain Reaction (PCR).
Management
Supportive therapy
Antibiotic therapy (e.g., fluoroquinolonesFluoroquinolonesFluoroquinolones are a group of broad-spectrum, bactericidal antibiotics inhibiting bacterial DNA replication. Fluoroquinolones cover gram-negative, anaerobic, and atypical organisms, as well as some gram-positive and multidrug-resistant (MDR) organisms. Fluoroquinolones) may be indicated for persistent disease.
Enteroinvasive E. coli
Pathophysiology
Pathophysiology is closely related to ShigellaShigellaShigella is a genus of gram-negative, non-lactose-fermenting facultative intracellular bacilli. Infection spreads most commonly via person-to-person contact or through contaminated food and water. Humans are the only known reservoir.Shigella.
BacteriaBacteriaBacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology penetrate through the epithelial wall of the intestine.
Intracellular multiplication → spread into adjacent epithelial cells
Additionally, produce:
Enterotoxins
CytotoxinsCytotoxinsSubstances that are toxic to cells; they may be involved in immunity or may be contained in venoms. These are distinguished from cytostatic agents in degree of effect. Some of them are used as cytotoxic antibiotics. The mechanism of action of many of these are as alkylating agents or mitosis modulators.Helicobacter
Inflammatory response → necrosisNecrosisThe death of cells in an organ or tissue due to disease, injury or failure of the blood supply.Ischemic Cell Damage (can produce ulcerationUlcerationCorneal Abrasions, Erosion, and Ulcers) → dysenteryDysenteryAcute inflammation of the intestine associated with infectious diarrhea of various etiologies, generally acquired by eating contaminated food containing toxins, biological derived from bacteria or other microorganisms. Dysentery is characterized initially by watery feces then by bloody mucoid stools. It is often associated with abdominal pain; fever; and dehydration.Gastroenteritis
Clinical presentation
Enteroinvasive E. coli presents very similarly to shigellosisShigellosisShigella and can be severe.
FeverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
NauseaNauseaAn unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses.Antiemetics and vomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia
Diagnosis
The diagnosis of EIECEIECEscherichia coli can be made by identifying specific genesGenesA category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.DNA Types and Structure using PCRPCRPolymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules.Polymerase Chain Reaction (PCR).
Management
Supportive therapy
Antimotility agents are contraindicated.
Antibiotics (e.g., fluoroquinolonesFluoroquinolonesFluoroquinolones are a group of broad-spectrum, bactericidal antibiotics inhibiting bacterial DNA replication. Fluoroquinolones cover gram-negative, anaerobic, and atypical organisms, as well as some gram-positive and multidrug-resistant (MDR) organisms. Fluoroquinolones, macrolidesMacrolidesMacrolides and ketolides are antibiotics that inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit and blocking transpeptidation. These antibiotics have a broad spectrum of antimicrobial activity but are best known for their coverage of atypical microorganisms. Macrolides and Ketolides) may be used in severe cases.
Enterohemorrhagic E. coli
Pathophysiology
Enterohemorrhagic E. coli results in clinical manifestations through the production of shiga toxin:
Localized effect: inhibits enterocyte protein synthesisSynthesisPolymerase Chain Reaction (PCR) → enterocyte death → inflammationInflammationInflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation
Systemic effect: vascular endothelial injury in glomeruli → microthrombi and renal dysfunction (hemolytic uremic syndromeHemolytic uremic syndromeA syndrome that is associated with microvascular diseases of the kidney, such as renal cortical necrosis. It is characterized by hemolytic anemia; thrombocytopenia; and acute renal failure.Hypocoagulable Conditions (HUSHUSHemolytic uremic syndrome (HUS) is a clinical phenomenon most commonly seen in children that consists of a classic triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Hemolytic uremic syndrome is a major cause of acute kidney injury in children and is most commonly associated with a prodrome of diarrheal illness caused by shiga-like toxin-producing bacteria.Hemolytic Uremic Syndrome))
Clinical presentation
IncubationIncubationThe amount time between exposure to an infectious agent and becoming symptomatic.Rabies Virus period: 2–10 days
Hemorrhagic colitisColitisInflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever.Pseudomembranous Colitis:
Serotype O157:H7 is commonly associated with HUSHUSHemolytic uremic syndrome (HUS) is a clinical phenomenon most commonly seen in children that consists of a classic triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Hemolytic uremic syndrome is a major cause of acute kidney injury in children and is most commonly associated with a prodrome of diarrheal illness caused by shiga-like toxin-producing bacteria.Hemolytic Uremic Syndrome:
ThrombocytopeniaThrombocytopeniaThrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia
Acute renal failureRenal failureConditions in which the kidneys perform below the normal level in the ability to remove wastes, concentrate urine, and maintain electrolyte balance; blood pressure; and calcium metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of proteinuria) and reduction in glomerular filtration rate.Crush Syndrome
The geneGeneA category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Basic Terms of Genetics that encodes shiga toxin using PCRPCRPolymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules.Polymerase Chain Reaction (PCR)
Management
Supportive therapy
Antimotility agents are contraindicated.
Antibiotics are contraindicated because of ↑ risk of HUSHUSHemolytic uremic syndrome (HUS) is a clinical phenomenon most commonly seen in children that consists of a classic triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Hemolytic uremic syndrome is a major cause of acute kidney injury in children and is most commonly associated with a prodrome of diarrheal illness caused by shiga-like toxin-producing bacteria.Hemolytic Uremic Syndrome.
Viral gastroenteritisGastroenteritisGastroenteritis is inflammation of the stomach and intestines, commonly caused by infections from bacteria, viruses, or parasites. Transmission may be foodborne, fecal-oral, or through animal contact. Common clinical features include abdominal pain, diarrhea, vomiting, fever, and dehydration.Gastroenteritis:inflammationInflammationInflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of the stomachStomachThe stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy and intestines, caused by a variety of virusesVirusesMinute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells.Virology. Common clinical features include abdominal painAbdominal PainAcute Abdomen, diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea, vomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia, feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, and dehydrationDehydrationThe condition that results from excessive loss of water from a living organism.Volume Depletion and Dehydration. The majority of cases of gastroenteritisGastroenteritisGastroenteritis is inflammation of the stomach and intestines, commonly caused by infections from bacteria, viruses, or parasites. Transmission may be foodborne, fecal-oral, or through animal contact. Common clinical features include abdominal pain, diarrhea, vomiting, fever, and dehydration.Gastroenteritis are self-limited; therefore, the diagnosis is generally clinical and the only required treatment is supportive therapy.
ShigellosisShigellosisShigella: caused by ShigellaShigellaShigella is a genus of gram-negative, non-lactose-fermenting facultative intracellular bacilli. Infection spreads most commonly via person-to-person contact or through contaminated food and water. Humans are the only known reservoir.Shigella species. S. dysenteriaeS. dysenteriaeA species of gram-negative, facultatively anaerobic, rod-shaped bacteria that is extremely pathogenic and causes severe dysentery. Infection with this organism often leads to ulceration of the intestinal epithelium.Shigella produces Shiga toxin. Individuals may experience feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, abdominal crampingAbdominal crampingNorovirus, and inflammatory diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea (with mucus, pus, and blood). Hemolytic uremic syndromeHemolytic uremic syndromeA syndrome that is associated with microvascular diseases of the kidney, such as renal cortical necrosis. It is characterized by hemolytic anemia; thrombocytopenia; and acute renal failure.Hypocoagulable Conditions is a potential complication. The diagnosis is confirmed with a stool culture. Management includes supportive therapy and antibiotics (for moderate to severe disease).
GiardiasisGiardiasisAn infection of the small intestine caused by the flagellated protozoan giardia. It is spread via contaminated food and water and by direct person-to-person contact.Giardia/Giardiasis: caused by GiardiaGiardiaA genus of flagellate intestinal eukaryotes parasitic in various vertebrates, including humans. Characteristics include the presence of four pairs of flagella arising from a complicated system of axonemes and cysts that are ellipsoidal to ovoidal in shape.Nitroimidazoles lamblia, a flagellated protozoan that can infect the intestinal tract.The hallmark symptom of giardiasisGiardiasisAn infection of the small intestine caused by the flagellated protozoan giardia. It is spread via contaminated food and water and by direct person-to-person contact.Giardia/Giardiasis is foul-smelling diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea (steatorrheaSteatorrheaA condition that is characterized by chronic fatty diarrhea, a result of abnormal digestion and/or intestinal absorption of fats.Diarrhea). Individuals who develop chronic infectionsInfectionsInvasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases.Chronic Granulomatous Disease may suffer from weight lossWeight lossDecrease in existing body weight.Bariatric Surgery, failure to thriveFailure to ThriveFailure to thrive (FTT), or faltering growth, describes suboptimal weight gain and growth in children. The majority of cases are due to inadequate caloric intake; however, genetic, infectious, and oncological etiologies are also common. Failure to Thrive, and vitamin deficiencies as a result of malabsorptionMalabsorptionGeneral term for a group of malnutrition syndromes caused by failure of normal intestinal absorption of nutrients.Malabsorption and Maldigestion. The diagnosis is made through detection of GiardiaGiardiaA genus of flagellate intestinal eukaryotes parasitic in various vertebrates, including humans. Characteristics include the presence of four pairs of flagella arising from a complicated system of axonemes and cysts that are ellipsoidal to ovoidal in shape.Nitroimidazoles organisms, antigens, or DNADNAA deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).DNA Types and Structure in the stool. Management includes supportive treatment and antimicrobial therapy.
Pseudomembranous colitisColitisInflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever.Pseudomembranous Colitis: infection caused by Clostridioides difficile. This species is commonly found in the normal gut microbiomeMicrobiomeCommensal organisms living in and on the bodyInnate Immunity: Barriers, Complement, and Cytokines, but pathogenesis occurs when there is an overabundance of C. difficile. Common symptoms include foul-smelling, nonbloody diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea, abdominal painAbdominal PainAcute Abdomen, and nauseaNauseaAn unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses.Antiemetics with vomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia. Diagnosis is made with stool PCRStool PCRNorovirus or enzyme assays. Treatment generally consists of discontinuing the offending antibiotic and administering oral fidaxomicin or vancomycinVancomycinAntibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear.Glycopeptides.
Colonic ischemiaIschemiaA hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation.Ischemic Cell Damage: hypoperfusion to areas of the colonColonThe large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy (often in regions without redundant sources of arterial blood). This hypoperfusion can be due to thrombosisThrombosisFormation and development of a thrombus or blood clot in the blood vessel.Epidemic Typhus, embolism, or hypotensionHypotensionHypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension. The acute phaseAcute phaseShort Bowel Syndrome of colonic ischemiaIschemiaA hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation.Ischemic Cell Damage is characterized by a classic triad of severe abdominal painAbdominal PainAcute Abdomen, vomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia, and diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea that may be bloody. Individuals may have a history of cardiovascular disease. Diagnosis is generally made with laboratory studies and CTACTAA non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases.Pulmonary Function Tests. Treatment includes fluid replacement, antibiotics, systemic anticoagulationAnticoagulationPulmonary Hypertension Drugs, and often surgery.
DiverticulitisDiverticulitisInflammation of a diverticulum or diverticula.Diverticular Disease: inflammationInflammationInflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of diverticula (small outpouching regions of the colonColonThe large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy) often due to obstruction with fecal matter. DiverticulitisDiverticulitisInflammation of a diverticulum or diverticula.Diverticular Disease presents with abdominal painAbdominal PainAcute Abdomen (most frequently in the LLQ), nauseaNauseaAn unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses.Antiemetics, and diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea that may be bloody. The definitive diagnosis is usually made with a CT scan. Treatment involves bowel rest, IV fluidsIV fluidsIntravenous fluids are one of the most common interventions administered in medicine to approximate physiologic bodily fluids. Intravenous fluids are divided into 2 categories: crystalloid and colloid solutions. Intravenous fluids have a wide variety of indications, including intravascular volume expansion, electrolyte manipulation, and maintenance fluids. Intravenous Fluids, and antibiotics.
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