GI Pathophysiology Flashcards
What is esophagitis?
It is the inflammation or infection in the esophagus
The most common cause of esophagitis is GERD
Patients with immunodeficiencies are most likely to experience infections
What drugs can cause esophagitis?
Bisphosphonates can irritate the esophagus if the patient does not remain upright after administration
Are swallowing disorders caused by esophagitis?
No, they actually represent a lack of neuromuscular coordination of the voluntary or involuntary muscles associated with swallowing
What is globus?
The feeling of something stuck in the throat, often related to anxiety
What happens in GERD?
The contents of the stomach spill into the esophagus due to a a weak lower esophageal (cardiac) sphincter.
The esophagus lacks a protective lining, so GERD can mimic chest pain that is usually experienced in a heart attack
Eventually inflammatory changes can occur, causing metaplasia
What are some non-pharmacological GERD treatments?
Weight loss
Extra pillow for sleep
Earlier supper
Avoiding trigger foods
What are some pharmacological treatments for GERD?
H2 receptor antagonists (antihistamines)
Proton pump inhibitors
Antacids (ex. Tums)
How do H2 antihistamines treat GERD?
These drugs bind to the H2 receptor in gastric parietal cells, reducing H+/K+ ATPase activity (inhibiting a precursor step to the release of protons)
Ex. Ranitidine, famotidine, cimetidine, nizatidine
How do proton pump inhibitors (PPIs) treat GERD?
They bind to H+/K+ ATPase of the gastric parietal cell, directly preventing the movement of protons into the stomach (acid secretion)
Ex. Pantoprazole, omeprazole, rabeprazole, esomeprazole, lansoprazole
Are proton pump inhibitors intended for long-term use?
No, they are designed for short-term treatment (6 weeks), but many patient have been taking PPIs chronically.
Chronic use of PPI = chronic elevation of stomach pH. This reduces digestive ability, pathogen elimination, absorption of certain minerals.
What are some good probing questions in patients who report stomach pain?
How frequently and how much they are taking
Have they seen an MD
Patient eating habits and schedule
Any triggers of GERD
Fatigue or paleness (loss of blood via ulcers)
Involvement of other body systems
Presence of angina
What is gastritis?
It is an infection or inflammation of the stomach
It is usually due to an H.pylori or NSAID overuse
Other etiology:
Alcohol
Atrophy of old age
Major stress (surgery, major burns, severe illness)
Autoimmune (pernicious anemia with B12 anemia)
What are the symptoms of gastritis?
Pain
Bloating
Burning sensation
Heavy feeling in stomach
Belching or flatulence
Nausea/vomiting
Blood in vomit (coffee-ground emesis)
Blood in stool (presence of blood that has passed through the entire GI tract)
How are the different etiologies that cause gastritis managed?
H. Pylori infection: (triple antibiotic therapy and a PPI)
NSAID use: Take with food
Alcohol: avoid excessive use of alcohol + smoking
Major stress (surgery, major burns, and severe illness): H2 antagonists and PPIs
What are the exact details of treatment of gastric ulcers?
- Usually given one or two antibiotics, choice dependent on allergies and sensitivity
- Bismuth (coating agent)
- H2 receptor antagonists
Surgery only if perforated or treatment has been ineffective
What are some commonalities seen in countries that have higher incidence of gastric cancer?
They all have high rates of H. Pylori infection, and a high diet in salt and smoked foods
What is the treatment of gastric cancer?
Most are adenocarcinomas
Treatment is surgery in the early stages, plus radiation and chemotherapy for later stages
What are some functions of the pancreas?
The pancreas has three parts; tail, body, and head
The pancreas also has endocrine and exocrine functions. Its exocrine functions involve the production and secretion of bicarbonate and digestive enzymes
What are the consequences of cancer in the head of the pancreas?
Cancer of the head of the pancreas can impinge on the ducts that could normally secrete bicarbonate and digestive enzymes. This will likely cause digestive problems
What is acute pancreatitis?
Acinar cell injury and duct obstruction that causes the leakage of activated digestive enzymes and subsequent auto digestion of pancreatic tissues
There is a spectrum of severity from self-limiting (mild disease) to fatal hemorrhagic pancreatitis
What are some symptoms associated with acute pancreatitis?
Severe epigastric pain that radiates to the upper back, nausea, and vomiting
Acute pancreatitis can be monitoring with elevated serum amylase and lipase levels.
Pancreatitis can complicate by becoming infected
What is chronic pancreatitis?
Chronic pancreatitis (80% due to alcoholism) presents as recurrent or epigastric pain with signs of pancreatic insuffiency
Alcohol is a pancreatic secretagogue, so it stimulates release of digestive enzymes, but these enzymes can clog up pancreatic ducts (causing obstruction)
What is pancreatic insufficiency?
Poor digestion, pain upon eating, greasy/smelly stools, malnutrition
What are some factors that increase GI secretions and motility?
Food
Nervous System (Enteric and PNS)
Activity (promotes GI motility, reducing transit time)
Disease (peripheral neuropathy, vessel damage can affect GI tract motility and function)
What are some factors that can decrease GI secretions and motility?
Lower food intake (carbs pass through GI tract faster than fats)
SNS stimulation (fight or flight)
Low activity increases GI transit time (affects older adults vs. active and younger people
What are some intestinal vascular diseases?
Hemorrhoids (swollen vein or group of veins in the anus)
Ischemic bowel disease (clot affecting a large bowel artery)
Chronic ischemia (ex. Heart failure)
Acute thrombosis of mesenteric arteries and veins (blood clot)
Non-occlusive intestinal infarction (tissue death)
Hernia (strangulation of tissue and subsequent ischemia)
Describe the flow of blood in the intestines?
The bowels are closely attached to the a rich supply of blood from arteries accompanied by the mesenteric veins.
When the blood reaches the intestines, it will absorb nutrients and other substances from the small intestines. This nutrient-rich blood is sent to the liver for processing and detoxification
Once the substances from the small intestines have been processed and detoxified, it is allowed to enter systemic supply
What are some things that are associated diarrhea?
Excessive motility
Loss of fluids due to high water content in faeces
Usually caused by infections or toxic agents due to epithelial disruption
What are some treatments for diarrhea?
Rehydration
Bulking agents
Anti-motility drugs (loperamide)
What are some things associated with constipation?
Inadequate mobility (acute/chronic)
Harder stool (more difficult to pass)
Impactions (could lead to hospitalization)
Discomfort
Enteric nervous system disruption
What are some treatments for constipation?
Motility agents (sennosides, bisacodyl, PEG)
Fluids
Bulking agents (fiber)
Stool softners (docusate)
What are some characteristics of gastrointestinal infections?
Bacterial infections are usually associated with travel and are food-borne
Most common pathogens: (Salmonella, Campylobacter, Shigella, Shiga toxin-producing E. coli)
What are the two types of gastrointestinal infections?
Non-inflammatory: usually less severe but still can cause dehydration
Inflammatory: associated with bloody diarrhea and presence of fecal leukocytes more likely, and more severe illness
How can diarrhea be managed by the patient?
Rehydration
Rest
Loperamide to reduce symptom duration
Simethicone for gas and cramping
Hygiene
Healthy diet
When should a case of diarrhea be referred to an MD?
Bloody diarrhea
Diarrhea has lasted over 7 days
Travel-associated
Immunocompromised
Fever, severely ill, debilitated
Complex patients
Extremes of age
What are some causes of intestinal obstruction?
Mechanical:
Stenosis
Stricture (due to inflamed surrounding tissue)
Intussusception (telescoping intestine)
Volvulus (twisting around itself)
Hernia (bulging through)
Adhesions
Neoplasms (rarely large enough to obstruct the lumen)
Describe intestinal neoplasms in detail?
Third most common cancer of internal organs (affects more than 200,000 people every year)
Adenoids and carcinomas account for 90% of intestinal neoplasms
Colon most often affected
Sporadic of familial (8:2)
Benign or malignant (3:1)
May be solitary or multiple
Primary or secondary (P>S)
What is the consequence of a intestinal neoplasm that is partially obstructing the lumen?
Constipation
Changes in bowel movement
Bleeding
Bloating
Weight loss
What is inflammatory bowel disease (IBD)?
Chronic inflammation of portions of the GI tract. Usually diagnosed in adolescence or early adulthood
Can cause complications such as malnutrition, colon cancer, intestinal fistulas and ruptures
What are the two main types of inflammatory bowel disease (IBD)?
Crohn’s disease
Ulcerative colitis
What are the causes of inflammatory bowel disease (IBD)?
Very complex etiology, with genetic, environmental and autoimmune factors result in inflammation in the gut and in other tissues
Risk factors: smoking, family history, fatty diet, hormonal medications,, stress, environmental pollution
What are some symptoms associated with inflammatory bowel disease (IBD)?
Abdominal pain
Mouth/stomach ulcers
Diarrhea
Rectal bleeding
Loss/change in appetite
Fever
Weight loss
Fatigue
Change/loss of menstrual cycle
What are some long-term complications of inflammatory bowel disease (IBD)?
Malnutrition and malabsorption
Anemia
Perforated bowel
Fistula, strictures, andabcess
Joint pain
Increases risk of colon cancer
What structural chnages occur in patients with Crohn’s disease?
Small intestine lumen wall:
Irregular nodular presentation with hyperaemia (looks red due to increased perfusion) and focal ulceration
Describe ulcerative colitis
It is family common (affects about 500,000 Canadians)
Redness, pain, and swelling in the colon are some symptoms associated with ulcerative colitis
What is the main difference between Crohn’s disease and ulcerative colitis?
Crohn’s disease tends to be more involved in the GI tract tissue
Ulcerative colitis is more surface associated
Are biologic drugs ineffective in inflammatory bowel disease?
No, they are effective
Anti-TNF BIologics
a2b7 Integrin blockers
Antibodies to p40 subunit of IL-12 and IL-23
