GI Disorders - Exam IV Flashcards
The GI tract constitutes ____ of the total human body mass
5%
What are the main functions of the GI tract?
- motility
- digestion
- absorption
- excretion
- circulation
Outermost to innermost layers of the GI tract
serosa - longitudinal muscle layer - circular muscle layer - submucosa - mucosa
Mucosa layers (outermost to innermost)
muscarlis mucosae, lamina propria, epithelium
The ____ is a smooth membrane of thin connective tissue and cells.
What does it do?
Serosa - it secrets serous fluid to enclose the cavity and reduce friction b/w muscle movements
The ____ ____ ____ contracts to shorten the length of the intestinal segment.
longitudinal muscle layer
The ____ ____ ____ contracts to decrease the diameter of the intestinal lumen.
Circular muscle layer
What 2 layers work together to propagate gut motility?
- longitudinal muscle layer
- circular muscle layer
Innervation of the GI organs up to the proximal transverse colon are supplied by the ____.
Celiac Plexus
Innervation of the descending colon & distal GI tract comes from the ____ ____ ____.
Inferior hypogastric plexus
How can the celiac plexus be blocked?
- transcrural
- intraoperative
- endoscopic ultrasound-guided
- peritoneal lavage
The ____ ____ lies b/w the smooth muscle layers.
What does it do?
Myenteric plexus - it regulates the smooth muscle
The submucosal plexus transmits information from the ____ to the ____ & ____.
Epithelium
Enteric
Central Nervous Systems
What is the muscalaris mucosa & what does it do?
A thin layer of smooth muscle in the mucosa of the GI tract
Functions to move the villi.
What is the lamina propria? What does it contain?
The middle layer of the mucosa of the GI tract.
It contains blood vessels & nerve endings.
True or False - there are immune & inflammatory cells in the mucosa of the GI tract.
True
What happens in the epithelium of the GI mucosa?
- where the GI contents are sensed
- enzymes are secreted
- nutrients are absorbed
- waste is excreted
What is the GI tract innervated by?
Autonomic nervous system
The extrinsic nervous system has ____ & ____ components.
SNS & PNS
The extrinsic SNS is primarily ____ & ____ GI motility
inhibitory & decreases
The extrinsic PNS is primarily ____ & ____ GI motility.
excitatory & activates
What is the independent nervous system in the GI tract?
What does it control?
Enteric Nervous System
Controls motility, secretion, & blood flow
The enteric system is comprised of the ____ ____ & ____ ____.
Myenteric Plexus & Submucosal Plexus
What does the myenteric plexus control? How is it carried out?
Controls motility
carried out by:
* enteric neurons
* interstitial cells of Cajal (aka ICC cells, GI pacemakers)
* smooth muscle cells
What does the submucosal plexus of the enteric nervous system control?
absorption, secretion, & mucosal blood flow
What do the myenteric plexus & submucosal plexus respond to?
Sympathetic and parasympathetic stimulation
Upper GI Endoscopy
- May be diagnostic or therapeutic
- Endoscope placed into esophagus, stomach, pylorus, and duodenum
- done w/ or w/o anesthesia
Anesthesia challenges with upper GI endoscopy
- sharing airway w/ endoscopist
- procedure performed outside of the main OR - don’t have all the bells & whistles
Colonoscopy
- may be diagnostic or therapeutic
- w/ or w/o anesthesia (rare)
Anesthesia Challenges w/ Colonoscopy
- pt dehydration d/t bowel prep & NPO status
- renal & CHF pts can be problematic when they are dry
- MAC (monitored anesthesia care) - BP drops w/ propofol
High Resolution Manometry (HRM)
- pressure catheter measures pressure along the entire esophageal length
- used to Dx motility disorders
- anti-reflux procedures
GI series w/ ingested Barium
- radiologic assessment of swallowing function
- GI transit
- series of pictures taken under fluoroscopy
Gastric emptying study
- pt fasts for at least 4 hours
- consumes a meal (eggs) w/ a radiotracer dye in it
- used to dx gastroparesis/problems emptying the stomach
Small Intestine manometry
- catheter measures contraction pressures & motility of small intestine
- evaluates contractions during 3 periods:
(fasting, during a meal, post-prandial) - recording time: 4hrs fasting, ingestion of meal, 2hrs post-meal
- abnormal results grouped into myopathic or neuropathic causes
Lower GI series
- involves the admin of a barium enema
- barium outlines the intestines & is visible on radiograph
- allows for detection of colon & rectal abnormalities
Examples of anatomical causes of esophageal disease:
What do they interrupt?
- diverticula
- hiatal hernia
- changes associated w/ chronic acid reflux
* they interrupt the normal pathway of food & change pressure zones of esophagus
Examples of mechanical causes of esophageal disease
- achalasia
- esophageal spasms
- Hypertensive LES (lower esophageal sphincter)
Examples of neurological causes of esophageal disease
- stroke
- vagotomy
- hormone deficiencies
Most common Sx of Esophageal Disease
- dysphagia
- heartburn
- GERD
Dysphagia
Difficulty swallowing
2 types
Oropharnygeal dysphagia
common after head & neck surgeries
Esophageal Dysphagia - 2 types
Classified based on physiology
* esophageal dysmotility: sx occur w/ both liquids & solids
* mechanical esophageal dysphagia: sx only occur w/ solid food
GERD (Gastroesophageal Reflux Disease)
Pt experiences effortless return of gastric contents into pharynx
Sxms: heartburn, nausea, “lump in throat”
What is Achalasia?
- one of the most common esophageal diseases
- neuromuscular disorder of esophagus
- outflow obstruction d/t inadequate LES tone & dilated hypomobile esophagus
Causes of Achalasia:
- loss of ganglionic cells of the esophageal myenteric plexus
- absence of inhibitory neurotransmitters of the LES
- Unopposed cholinergic LES stimulation (LES can’t relax)
- Esophageal dilation w/ food unable to pass into stomach
What do people w/ achalasia have an increased risk of long-term?
esophageal cancer
Diagnosis for Achalasia
esophageal manometry
esophagram
Symptoms of Achalasia:
- dysphagia
- regurgitation
- heartburn
- chest pain
- hard time getting food to pass adequately
Type 1 Achalasia
minimal esophageal pressure
* responds well to myotomy
Type 2 Achalasia:
entire esophagus pressurized
* responds well to treatment
* has the best outcomes
Type 3 Achalasia
esophageal spasms w/ premature contractions of the esophagus
* has the worst outcomes
Achalasia Tx
- ALL TREATMENTS PALLIATIVE
- Meds: nitrates, CCBs - relax LES
- endoscopic botox injections
- pneumatic dilation - most effective (balloon dilation)
- Laparascopic Hellar Myotomy - best surgical tx
- peri-oral endoscopic myotomy (POEM)
- esophagectomy - only for advanced dx
POEM: peri-oral endoscopic myotomy & risks
- endoscopic division of LES muscle layers
- 40% develop pneumothorax or pneumoperitoneum
All achalasia pts are ____.
What is indicated b/c of this?
- high risk for aspiration
- RSI or awake intubation (full stomach)
Diffuse Esophageal Spasms
- spasms that occur in the distal esophagus
- d/t autonomic dysfunction
- occur more in elderly
- Dx: esophagram
- pain mimics angina
Tx for diffuse esophageal spasms
NTG, antidepressants, PDE-I’s
What are Esophageal Diverticula
outpouchings in the wall of the esophagus
Pharyngoesophageal Diverticula
- Zenker Diverticulum
- cause bad breath d/t food retention in the pockets of their throat
Midesophageal Diverticula causes
- deeper down
- caused by old adhesions, inflamed lymph nodes
Epiphrenic Diverticula
- Surpadiaphragmatic
- pts may experience achalasia
All diverticula pts are ____ ____.
What is indicated d/t this?
aspiration risks
* removal of particles before putting them to sleep & RSI
Hiatal Hernia
herniation of the stomach into the thoracic cavity
* occurs through the esophageal hiatus in the diaphragm
Cause of hiatal hernia:
weakening in anchors of GE junction to the diaphragm
Sxms of Hiatal Hernia
- may be asymptomatic
- often have GERD
How does esophageal caner present?
Progressive dysphagia & weight loss
Why does esophageal cancer have a poor survival rate?
Abundant lymphatics in the area leads to lymph node metastasis
What are the 2 common types of esophageal cancer?
- Adenocarcinomas (lower esophagus) - r/t GERD, barrett’s esophagitis, obesity
- Squamous cell carcinoma
Is an esophagectomy curative or palliative?
Can be either
How can an esophagectomy be performed?
- transthoracic
- transhiatal
- minimally invasive
There is a high risk of ____ ____ ____ with esophagectomy surgeries.
Recurrent laryngeal nerve injury
* 40% resolve spontaneously
Pt concerns r/t esophagectomy
- pts malnourished pre-op and for months post-op
- pancytopenia & dehydration if h/o chemo/radiation
- post-esophagectomy pts are high risk of aspiration for life
GERD
Incompetence of gastro-esophageal junction - leads to reflux
* 15% of adults
Sxms of GERD
- heartburn, dysphagia, mucosal injury
Reflux contents include ____, ____, ____ ____, & ____.
- HCl
- pepsin
- pancreatic enzymes
- bile - associated w/ Barret metaplasia & adenocarcinoma
3 mechanisms of GE incompetence
- Transient LES relaxation - elicited by gastric distention
- LES hypotension
- Autonomic dysfunction of GE junction
What is the normal LES pressure?
GERD pressure?
- measured using manometry
- LES normal - 29mmHg
- GERD - 13mmHg
Treatment of GERD
- Avoid trigger foods
- Meds: antacids, H2 blockers, PPIs
- Surgery
What is a Nissen Fundoplication?
wrap stomach around esophagus so the stomach muscles tighten where the LES is
What is a Toupet?
Similar to Nissen - not as high up
What is a Linx procedure?
- newer procedure - magnets that open and close around sphincter - less invasive
Pre-op Interventions: GERD
- Cimetidine, Ranitidine - decrease acid production & increase pH
- PPIs night before and morning of
- sodium citrate - nonparticulate PO antacid (OB c-section)
- Metoclopramide - gastrokinetic agent; 3rd line - reserved for DM, obese, pregnant
- Aspiration precautions – RSI, cricoid pressure controversial
Factors that increase intra-op Aspiration risk: LONG ASS LIST
- emergent surgery - full stomach (digestion halted w/ traumas)
- full stomach
- difficult airway
- inadequate anesthesia depth
- lithotomy
- autonomic neuropathy
- Gastoparesis - DM
- Pregnancy
- Increased intraabdominal pressure
- severe illness
- morbid obesity
What is the stomach & what does it do?
- J-shaped sac that serves as a reservoir for large volumes of food
- mixes & breaks down food to form chyme
- slows emptying into the small intestine
How small must solids be broken down to before entering the duodenum?
1-2mm particles
How is the motility of the stomach controlled?
intrinsic & extrinsic neural regulation
SNS stimulation ____ these contractions via the ____ ____.
inhibits, sphlanchnic nerve
PNS stimulation to the vagus nerve increases the ________________ of the stomach.
number & force of contractions
The intrinsic nervous system provides ____ for motility.
Coordination
What is the neurohormonal control of the stomach?
- Gastrin & Motilin - increase the strength & frequency of contractions
- Gastric inhibitory peptide - inhibits contractions
What is the most common cause of non-variceal upper GI bleeding?
Peptic Ulcer disease
* 10% women, 12% men
* 15,000 deaths/yr
PUD may be associated with ____.
Helicobacter Pylori
Sxms of PUD:
burning epigastric pain w/ fasting & improved w/ meals
There is a ____ risk of perforation in PUD pts who don’t receive treatment
10%
PUD Perforation Symptom
- sudden/severe epigastric pain - acidic secretions leaking into peritoneum (EMERGENCY)
What causes moratlity r/t PUD perforation?
Shock or perforation >48hrs
Gastric Outlet Obstruction onset
- Can be acute or chronic
- acute d/t edema & inflammation in pyloric channel at the beginning of the duodenum
Pyloric obstruction sxms
recurrent vomiting, dehydration & hypochloremic alkalosis
Repetitive ulceration & scarring may lead to ____ - ____ & ____ ____.
Fixed-stenosis & chronic obstruction
Tx for gastric outlet obstruction
- NGT (decompress the stomach)
- IV hydration
- normally resolves in 72h
Type I Gastric Ulcer location
Along the lesser curvature close to incisura; no acid hypersecretion
Type II Gastric Ulcer
2 ulcers - 1st on gastric body, 2nd duodenal
* usually acid hypersecretion
Type III Gastric Ulcer
Pre-pyloric with acid hypersecretion
Type IV Gastric Ulcer
At lesser curvature near gastroesophageal junction
* no acid hypersecretion
Type V Gastric Ulcer
Anywhere in the stomach
* usually seen w/ NSAID use
Common causes of gastric ulcers include:
NSAIDs, H. Pylori, ETOH
Tx for gastric ulcers:
- Antacids, H2 blockers, PPIs
- Prostaglandin Analogues, cytoprotective agents
H. Pylori Tx:
Triple Therapy
* 1 Abx
* PPI
* 14 days
What is Zollinger Ellison Syndrome?
Non B cell islet tumor of the pancreas - causes gastrin hypersecretion
* gastrin stimulates gastric acid secretion
* gastric acid normally inhibits further gastrin release - this is absent in ZE syndrome!
Sxms of Zollinger Ellison Syndrome
very high stomach acid levels leading to -
* PUD, erosive esophagitis, diarrhea
Incidence of ZE Syndrome
- 0.1-1% of PUD pts
- males > females
- ages 30-50
Up to 50% of pts w/ gastrinomas are ____ at the time of diagnosis.
metastatic
Tx of ZE syndrome
PPI & Surgical resection of gastrinoma
Pts w/ ZE syndrome have: (3 things)
- increased gastric fluid volume
- possible electrolyte imbalances
- endocrine abnormalities
Pre-op Considerations for ZE Syndrome
- correct electrolytes
- increase gastric pH w/ meds
- RSI
What does small intestinal motility do? What is the purpose of this?
mixes contents of the stomach w/ digestive enzymes
* further reduces particle size & increases solubility
What is the major function of the small intestine?
circulate the contents & expose them to the mucosal wall
* maximizes the absorption of water, nutrients, & vitamins - before entering large intestine
The circular & longitudinal muscle layers coordinate to achieve ____.
Segmentation
What is segmentation?
Isolation of a segment of intestine when 2 nearby areas contract
What is the purpose of segmentation?
Allows the contents to remain in the intestine long enough for essential substances to be absorbed into circulation
What is Segmentation controlled by?
Mainly by the enteric nervous system &
modulation of motility by the extrinsic nervous system
Reversible causes of small bowel dysmotility:
- Mechanical Obstruction: hernias, malignancy, adhesions, volvuluses
- bacterial overgrowth - alterations in absorptive function
- ileus, electrolyte abnormalities, critical illness
Structural Irreversible Causes of small bowel dysmotility
Scleroderma, connective tissue disorder, IBD
Neuropathic Irreversible causes of small bowel dysmotility
- pseudo obstruction - intrinsic & extrinsic nervous systems are altered
- intestines produce weak, uncoordinated contractions
- Cannot move food forward - bloating, nausea, vomiting, abd. pain
- food stuck in intestines & grows bacteria
What is the large intestine?
acts as a reservoir for waste & indigestible material before elimination
* it exctracts remaining electrolytes & water
Physiology of the large intestine
- distention of ileum - relaxes ilocecal valve to allow intestinal contents to enter colon
- subsequent cecal distention will contract ileocecal valve
- colon exhibits giant migrating complexes
Giant migrating complexes serve to produce -
how often does this occur?
mass movements across the large intestine
6-10x/day
Colonic Dysmotility manifests as what 2 symptoms?
- altered bowel habits
- intermittent cramping
What are the most common diseases associated with colonic dysmotility?
IBS
IBD
Rome II criteria for IBS
Abdominal discomfort w/ 2 of -
* defecation relieves discomfort
* pain associated w/ abnormal frequency (>3x per day or < 3x/week)
* pain associated w/ a change in the form of the stool
In IBD - the contractions & giant migrating complexes are suppressed d/t colonic wall compression by the inflamed mucosa. True or False?
False
* the giant migrating complexes remain & are increased in frequency
What can the increased frequency of giant migrating complexes in IBD lead to?
further compresses the inflamed mucosa
* hemorrhage, thick mucus secretion, significant erosions
