Special pathology - gastrointestinal Flashcards
bright fresh blood in feces is termed
hematochezia
dark blood in feces is termed
melena
neurogastroenterology is
the field of study of the Enteric nervous system
name the two ganglia of the enteric nervous system and what type of innervtion belongs to each
myenteric ganglia (motoric innervation)
submucosal ganglia (motoric and secretory innervation)
layers of the GI Mucosa
– Mucous epithelium
– Lamina propria
– Muscular layer of mucosa
layers of the GI smooth musculature
– Outer longitudinal
– Middle circular
– Inner oblique
2 types of passive absorption
Diffusion
Osmosis (water, chloride, vitamiin C)
NB concentration gradients
Tenesmus
frequent urge to go to the bathroom without being able to go, unproductive straining to go
what is the clinical technique called ballottement
Ballottement is the technique used to evaluate a flowing or movable structure. The nurse gently bounces the structure by applying pressure against it and then waits to feel it rebound. This technique may be used, for example, to check the position of an organ or a fetus.
used to evaluate density and size of abdominal organs by their movement away from and back to the abdominal wall
name 3 clinical techniques used on teh abdomen of a GI suspect patient
2) observing the contour of the abdomen for distention or contraction
2) palpation through the abdominal wall or per rectum
3) abdominal percussion to detect “pings,” -gas-filled
TLI/PLI
Trypsin-like immunoreactivity for diagnosis of pancreatic exocrine insufficiency
Pancreatic Lipase Immunoreactivity has been shown to be sensitive and specific for pancreatitis and have the advantage of remaining increased after the TLI has returned to normal.
how does B12 relate to GI diseases?
B12 or cobalamin deficiency may cause diarrhea, nausea, constipation, bloating, gas, and other gastrointestinal symptoms
A complex interaction occurs between folic acid, vitamin B12, and iron.
B12 is required as a cofactor by gut microbes for various biological processes.
how does folate relate to GI diseases?
folate/folic acid or vitamin B9 deficiency can cause a range of gastrointestinal problems, including diarrhea, stomach pain, and indigestion.
A complex interaction occurs between folic acid, vitamin B12, and iron.
In addition, it helps to increase appetite when needed and stimulates the formation of digestive acids.
Granulomatous Enteritis
is a form of inflammatory bowel disease that affects predominantly the small intestine in horses.
Clinical parasitism depends on
the number and pathogenicity of the parasites, which depend on the biotic potential of the parasites.
Johne’s Disease
is a contagious, chronic, and usually fatal infection that affects primarily the small intestine of ruminants.
Johne’s disease is caused by Mycobacterium avium subspecies paratuberculosis.
name 4 types of Noninfectious diseases of the GI tract
*dietary overload or indigestible feeds
*chemical or physical agents
*obstruction of the stomach and intestines
*congenital defects
Ptyalism
Ptyalism is a condition where you make too much saliva.
a reflex that occurs as a protective
reaction of the body in response to irritation of the mucous membranes
excessive salivation
name 3 types of receptors of the emetic center
serotonergic
adrenergic receptors
+ neurokinergic receptors
are located in the adjacent nucleus tractus solitarii- stimulate the emetic center
name the 2 ways of activating the emetic center
- indirectly by humoral pathways via the chemoreceptor trigger zone
- directly through neural pathways from the GI tract, cerebral cortex, or vestibular system
the chemoreceptor trigger zone is located in
the area postrema in the floor of the fourth ventricle
lacks a blood-brain barrier!
endogenous substances that can stimulate the chemoreceptor trigger zone for emesis can be (2)
uremic or hepatoencephalopathic toxins
exogenous substances that can stimulate the chemoreceptor trigger zone for emesis can be (2)
drugs, toxins
Abdominal pain is induced by stimulation of
visceral nociceptors
Activation of nociceptors requires previous sensitization by pathological events:
inflammation
ischemia
acidosis
dolor coli
Colic
a number of disease conditions that are associated with clinical signs of
abdominal pain
Colica bilaris seu hepatica
biliary colic
Colica pancreatica
pancreatic colic
Colica renalis renal
colic caused by kidney stones
colic can be divided into 3 types:
- Symptomatic colic
Infectious diseases, invasive surgery, and gynecological conditions that cause pain. - Pseudocolic (pain)
Associated with the pain in the liver, kidneys, lungs, pleura, etc. - True colic
Typically occur with gastrointestinal disorders. Most common in horses.
Some Causes of true colic: (6)
Dental diseases and masticatory muscle disorders
Inflammation
Ulceration
Tumors
proliferation of intestinal parasites
Ileus
4 feed related causes of true colic
Inadequate feeding and keeping conditions:
overfeeding
heavy physical load after feeding
spoiled and contaminated (e.g. soil) feeds
harmful inedible impurities (toxins, mechanical irritation)
Ileal impaction is
a condition in which the terminal end of the small intestine becomes blocked by a bolus of feed, resulting in progressive distension of the small intestine and onset of colic.
Ascarid impaction is
usually occurs after worming a young horse that has a large parasite load. Huge numbers of these large parasites die en masse, drift downstream and obstruct the intestine, causing signs of colic.
intestinal Volvulus is
A small intestinal (SI) volvulus occurs in the horse when the intestine rotates on its mesenteric axis through an angle greater than 180o, resulting in strangulation.
Ileus
Loss of motility in the intestines
Functional obstruction of abnormal gastrointestinal (GI) transit
(Postoperative ileus/ paralytic ileus)
2 types of Obstipation
- Spastic obstipation
- Atonic obstipation
- Spastic obstipation is
associated with slowed transit of chyme due to circular muscular contraction in the colon
- Atonic obstipation
associated with the reduced muscle tone of the colon and stoppage of peristalsis.
diarrhea causing Pathogens can be divided into 3
- induce intestinal secretion enterotoxic or enterotoxigenic (E. coli)
- induce inflammation (Lawsonia intracellularis)
- those that are invasive (Salmonella)
- Noninflammatory diarrheas are produced by organisms that
disrupt the absorptive or secretory mechanisms of the enterocytes without destroying the cells
Usually, affect the more proximal portions of the bowel
e.g. enterotoxic E. coli
Rotavirus
Cryptosporidium parvum
- Inflammatory diarrheas are produced by organisms that
produce cytotoxins or are invasive and activate cytokines that initiate inflammatory cascades
The inflammatory diarrheas generally affect the ileum, cecum, or colon.
e.g. Salmonella
Brachyspira
Lawsonia
Combinations of what mechanisms are present in most enteric diseases
Combinations of (noninflammatory+inflammatory) are present in most
enteric diseases
diarrhea classification based on mechanism/character
Osmotic diarrhea
Secretory diarrhea
Exudative diarrhea
Malabsorption Leads to
osmotic diarrhea
which is usually a problem of the small intestine but can cause secondary colonic malfunction
causes of osmotic diarrhea
osmotic diarrhea
cause:
loss of digestive enzmes secondary to microvillus
disruption
crypt or villus enterocyte death
space-occupying lesions of the lamina propria
Osmotic diarrhea involves an
unabsorbed osmotically active substance that draws water from the plasma into the intestinal lumen along osmotic gradients.
nutrients are maldigested or malabsorbed, remain within the intestinal lumen- osmotically attract water
Maldigestion caused by
Exocrine pancreatic insufficiency
Maldigestion mechanics
Retention of nutrients – alterations in intestinal microflora and fermentation of
carbohydrates
further increasing numbers of osmotically active particle in lumen
exerting an osmotic gradient across intestinal mucosa
= osmotic diarrhea
Secretory Diarrhea is
caused by abnormal ion transport in intestinal epithelial cells
e.g.
endogenous enteric hormones or neuropeptides
inflammatory cell products
bacterial enterotoxins
laxatives
what type of diarrhea in Enteropathogenic Escherichia coli and
IBD
Secretory Diarrhea caused by abnormal ion transport in intestinal epithelial cells.
Exudative diarrhea is
Increased mucosal permeability
fluids, electrolytes, proteins and blood “can leak out”
accompanies erosive, ulcerative, GI-neoplastic, and inflammatory processes
some parasitic infections (hookworm) in which opening of the tight junctions between enterocytes allows macromolecules into the intestinal lumen (protein-losing enteropathy) cause what type fo diarrhea
exudative diarrhea
water content of normal feces versus diarrhea (%)
Normal feces -75% water
Diarrheal feces ≥ 85% water
excess fluid loss and dehydration lead to what cascade?
hypovolemia with resultant hemoconcentration and then
inadequate tissue perfusion
Acidosis causes a reduction in pH-dependent what
enzyme system functions
Differentiation of small intestine diarrhea from large intestine diarrhea
Frequency
Frequency of defecation will be normal to only mildly increased in small bowel diarrhea
Markedly increased in large bowel
Differentiation of small intestine diarrhea from large intestine diarrhea
Fecal volume
Fecal volume will be normal to increased in small bowel diarrhea
Decreased in large bowel
Differentiation of small intestine diarrhea from large intestine diarrhea
Fecal mucus
Fecal mucus is usually absent in small bowel diarrhea
Often present in large bowel
Differentiation of small intestine diarrhea from large intestine diarrhea
Tenesmus (frequent evacuation urge)
Tenesmus absent in small bowel but often present in large bowel diarrhea
Differentiation of small intestine diarrhea from large intestine diarrhea
Urgency
Evacuation urgency is absent in small bowel diarrhea
Often present in large bowel
Differentiation of small intestine diarrhea from large intestine diarrhea
Vomiting
Vomiting may be present in both small and large bowel diarrhea syndromes
Differentiation of small intestine diarrhea from large intestine diarrhea
Steatorrhea
Steatorrhea, fatty stools, may be present in small bowel but not large bowel diarrhea
Differentiation of small intestine diarrhea from large intestine diarrhea
Dyschezia (difficulty with evacuation)
Dyschezia absent in small bowel but often present in large bowel diarrhea
Differentiation of small intestine diarrhea from large intestine diarrhea
Weight loss
Weigth loss common to small bowel
Uncommon in large bowel diarrhea
Hyposalivation can result in
reduced resistance to oral mucosal infections, and impaired chewing and swallowing.
*Late-stage inflammation of salivary glands
*Innervation disturbances
*Drugs – atropine
*Diseases with fever, due to inhibition of conditioned reflex salivary secretion
Gingivitis is
inflammation of the gingiva aka the gums
Periodontitis is
inflammation of the tissues surrounding and anchoring the teeth / gingiva, periodontal
ligament, alveolar bone, and cementum
Stomatitis
refers to inflammation of the oral mucosa
Erosive and Ulcerative Stomatitis
Erosion - loss of part of the thickness of the surface epithelium.
ulcers are full-thickness epithelial losses exposing the basement membrane.
malignant catarrhal fever
Malignant catarrhal fever is a severe, often fatal, lymphoproliferative disease of artiodactyls (cloven-hooved mammals) caused by ruminant gammaherpesviruses.
Catarrh a build-up of mucus in an airway or cavity of the body.
artiodactyls are even-toed ungulates
Catarrh is
a build-up of mucus in an airway or cavity of the body.
Eosinophilic Stomatitis
= oral eosinophilic granulomas or ulcers in cats.
Similar lesions occur sporadically in a variety of canine breeds.
is suspected to be a immune-mediated mechanism hypersensitivity reaction
Lymphoplasmacytic Stomatitis
is a chronic, rapidly progressive, idiopathic periodontal disease of the cat.
may be associated with feline leukemia virus (FeLV) and/or FIV infection
The oral mucosa may be hyperplastic and ulcerated.
Epulis is
a nonspecific term that designates a growth of the gingiva or Gingival hyperplasia, overgrowth of the gums (fibrous
submucosa).
In the dog, what % of tumors of the alimentary system are
in the oral cavity and oropharynx.
70%
from simple epithelial hyperplasia to malignant neoplasms with metastases to distant sites
Squamous cell carcinomas occur in the oral cavity,
particularly in old cats, in which they account for what %
of oral neoplasms?
60%
Enamel is the only substance in the body incapable of
turnover and repair.
Enamel is the thin outer covering of a tooth.
hypsodont teeth are
Hypsodont is a pattern of dentition with high-crowned teeth and enamel extending past the gum line, providing extra material for wear and tear. Continuous growth.
examples cows, horses
disadvantages; uneven wear, formation of ridges
The initial multiplication of some enteric viruses (e.g., feline parvovirus) may occur in
the tonsils.
Malignant neoplasms of epithelial origin in the tonsils are termed
squamous cell carcinomas
Malignant neoplasms of lymphoid origin in the tonsils are termed
lymphoma, lymphosarcoma
Esophageal healing is relatively rapid,
normal epithelial turnover rate is
5 to 8 days
3 potential causes of dysfunction of the esophageal phase of swallowing:
mechanical (or anatomic) lesions
functional (or neuromuscular) lesions
inflammatory (esophagitis) conditions
esophageal strictures
refers to the abnormal narrowing of the esophageal lumen; it often presents as dysphagia
hiatal hernia
a type of hernia in which abdominal organs (typically the stomach) slip through the diaphragm into the middle compartment of the chest
may result in gastroesophageal reflux disease
gastroesophageal intussusception
an unusual condition in which the stomach is translocated into the intrathoracic esophageal lumen
Grain overload
also known as acidosis or grain poisoning. It occurs when cattle, sheep or goats eat large amounts of grain, and can result in acidosis, slowing of the gut, dehydration and often death.
(Lactic acidosis, Carbohydrate engorgement, Rumenitis)
Subacute ruminal acidosis
is caused by the ingestion of feed high in rapidly fermentable carbohydrates or deficient in physically active fiber.
is a metabolic disease in high-producing dairy cattle. This disease is caused by feeding high concentrate diets and is defined as a depression of ruminal pH below 5.6 at least 3 h/day.
(Chronic ruminal acidosis, Subclinical ruminal acidosis)
Bloat also known as
Ruminal tympany
an excessive volume of gas in the rumen. Ruminal tympany may be primary, known as frothy bloat, or secondary, known as free-gas bloat
Ruminal atony is
forestomach hypomotility disorder resulting in loss of appetite, apathy, bloat (ruminal tympany), green faeces, colic etc.
What can ruminal atony and the resulting metabolic acidosis cause in
- hooves?
laminitis
Traumatic reticuloperitonitis is a consequence of
perforation of the reticulum
Cattle commonly ingest foreign objects because they do not discriminate against metal materials in feed and do not completely masticate feed before swallwoing.
Contractions of the reticulum promote penetration of the wall by the foreign object.
the alkaline buffering capacity of rumen fluid is not great in comparison with?
its ability to buffer acids.
Ruminants are well adapted to buffer the acid produced in the rumen.
ruminal alkalosis can be caused? (3)
- High-protein diet
- contaminated feedstuffs
- grazing lush young grass pastures that are too high in protein
Ruminal ciliates cannot survive if the pH goes up over
7.5
ciliates are single-celled organisms that, at some stage in their life cycle, possess cilia, short hairlike organelles used for locomotion and food gathering.
Ruminal tympany is
(bloat)
(Over)distension of the rumen and reticulum with fermentation gases =
(abnormal accumulation of gas in the ruminal forestomachs).
Caused by feeding excessive amounts of highly fermentable carbohydrates.
Secondary ruminal tympany is
esophageal obstruction –excess of free gases on the top of the ruminal contents that cannot be expelled from the rumen by eructation.
In the Stomach and Abomasum, the gastric epithelial layer is one cell thick. Its
turnover rate is
2 to 4 days
What controls gastric emptying?
The pyloric sphincter controls gastric emptying – elevated acidity and water levels in the gastric contents (chyme) cause the sphincter to open.
Increased acidity in duodenal chyme causes the sphincter to close.
the “hunger hormone” is called
ghrelin
(pylorospasm) is
Pyloric spasm is closure of the pylorus due to muscle spasm, leading to delay in the passage of stomach contents to the duodenum and vomiting. It is usually associated with duodenal or pyloric ulcers or tumors.
Pyloric insufficiency is
excessively rapid gastric emptying.
The decreased acidity of the chyme that reaches the duodenum influences contraction of the sphincter
+ Innervation problems
Various disruptions of the mucosal immune system can lead to
chronic inflammatory responses that are histologically similar
Various disruptions of the mucosal immune system can be induced by: (3)
disruption of the endogenous microflora
interference with the mucosal barrier
dysregulation of the mucosal immune system
Healthy individuals are tolerant to their own intestinal microflora.
In IBD though, ….?
In inflammatory bowel disease (IBD), tolerance is broken.
Lymphangiectasia is
Dilation of lacteals is idiopathic or secondary to obstruction of flow.
Also known as “lymphangiectasis”, is a pathologic dilation of lymph vessels. When it occurs in the intestines of dogs, it causes a disease known as “intestinal lymphangiectasia”.
This disease is characterized by lymphatic vessel dilation, chronic diarrhea and loss of proteins such as serum albumin and globulin. It is considered to be a chronic form of protein-losing enteropathy.
necrotizing processes of the intestinal lamina propria involve
necrosis of the gut associated lymph tissues (GALT) with extension to the overlying epithelium
name 2 disease examples in which necrosis of the gut associated lymph tissues
(GALT) occurs
bovine viral diarrhea (BVD) of cattle
Rhodococcus equi infection of horses
Luminal Disturbance refers to?
Can be caused by? (3)
a disturbance within the intestinal lumen resulting in failure of digestion
Can be caused by:
bacterial overgrowth
lack of pancreatic enzymes (EPI)
increased destruction of enzymes by acid hypersecretion called Zollinger-Ellison syndrome
Dysbiosis refers to?
Can be caused by? (5)
disturbance of the normal gut microbiome
Following:
antibiotic usage
infection
sudden dietary change
overgrowth of microflora
underlying mucosal immunoincompetence or inflammation
Cobalamin deficiency
Not uncommon in dogs because there are some predisposed breeds e.g. Shar-Peis, beagles, collies.
Defects in cobalamin–intrinsic factor uptake in the ileum via genetic mutations
Microvillar Membrane Damage
histologic villus damage
massive impairment of mucosal function can occur if the microvilli are damaged
enteropathic E. coli infection frequent cause
carrageenan gum in seaweeds, or lectins, can cause a loss of brush border enzymes and carriers and surface area
Enterocyte Dysfunction
bacterial toxins cause without histologic damage:
interfere with enterocyte function
subcellular loss of brush border proteins
Malnutrition and ischemia impair function + increase epithelial permeability.
Villus Atrophy
causes loss of intestinal surface area and results in fat malabsorption
- decrease in the production of enterocytes
- increase in the rate of enterocyte loss
- causeva mild to moderate diarrhea
Cytotoxic drugs (vincristine) = crypt arest
Parvovirus infection = crypt destruction,
cause complete villus and crypt collapse and severe diarrhea
Infectious agents that damage enterocytes can infect what exactly
- villus tip (e.g., rotavirus)
- midvillus (e.g., coronavirus)
Disorders of intestinal Innervation
Influence intestinal motility,
aganglionosis (ertain nerve cells are missing from the muscle layers of part of the large intestine) and dysautonomia
malfunction of:
cranial nerves
spinal nerves, ganglia
and/or autonomic nervous system
Disordered intestinal Motility
Irritable bowel syndrome (IBS) is a functional disorder with primary changes in motility.
Secondary motility alterations:
intestinal obstruction
adynamic ileus (also known as paralytic ileus)
inflammatory and infectious enteropathies
Hypersensitivity of the GI tract
Sensitization of a patient to a dietary antigen.
IgE-mediated allergic reaction
Mast cell mediators can have generalized systemic effects such as anaphylaxis, remote effects such as pruritus and urticaria, or only local effects on the intestine, inducing rapid changes in absorption and secretion, mucus secretion, epithelial and endothelial
permeability, and gut motility.
Neoplasms in the GI tract
Diffuse tumors that infiltrate the mucosa, cause small intestine dysfunction.
Malignant cells can:
obstruct blood and lymphatic flow
cause ischemia = enterocyte function is impaired;
mucosal villus atrophy or ulceration
Solitary tumorsof the GI tract can cause
Dysfunction through the effects of partial obstruction, with stasis of ingesta and secondary bacterial overgrowth.
More typically, solid tumors are associated with signs such as intestinal obstruction, bleeding, and cancer-associated cachexia.
name 3 Congenital Abnormalities of the GI tract
intestinal stenosis
atresia (= an orifice is closed or absent)
random duplications of segments of both SI and large intestine (LI)
Duplications are cystlike lesions that rarely cause clinical signs unless they cause an obstruction. Blind-ending diverticula may predispose to foreign body entrapment,
bacterial overgrowth, GI bleeding or perforation.
Cystic vitelline ducts can occur with umbilical leakage of SI contents if there is a persistent ductus omphaloentericus.
Arteriovenous fistulae can cause SI hemorrhage.
define obstipation
severe or complete constipation
obstipation vs constipation difference
Constipation is defined as infrequent, incomplete, or difficult defecation with passage of hard or dry feces. This does not imply abnormal motility or loss of function.
Obstipation denotes intractable constipation caused by prolonged retention of hard, dry feces; defecation is impossible in the obstipated patient.
