T4 - GI Assessment Flashcards
What percentage of the total human body mass does the GI tract constitute?
Approximately 5%.
What are the main functions of the GI tract?
Motility, digestion, absorption, excretion, and circulation.
What are the layers of the GI tract from outermost to innermost?
Serosa, longitudinal muscle layer, circular muscle layer, submucosa, and mucosa.
What are the components within the mucosa from outermost to innermost?
Muscularis mucosae, lamina propria, and epithelium.
What is the function of the serosa?
It is a smooth membrane of thin connective tissue and cells that secrete serous fluid to enclose the cavity and reduce friction between muscle movements.
What is the function of the longitudinal muscle layer in the GI tract?
It contracts to shorten the length of the intestinal segment.
What does the circular muscle layer do?
It contracts to decrease the diameter of the intestinal lumen.
How do the longitudinal and circular muscle layers work together?
They work together to propagate gut motility.
Which plexus supplies innervation to the GI organs up to the proximal transverse colon?
The celiac plexus.
Where does the innervation of the descending colon and distal GI tract come from?
The inferior hypogastric plexus.
What are some of the approaches to block the celiac plexus?
- Transcrural
- Intraoperative
- Endoscopic ultrasound-guided
- Peritoneal lavage
Where is the myenteric plexus located and what is its function?
The myenteric plexus is situated between the smooth muscle layers and regulates their function.
What is the role of the submucosal plexus in the GI tract?
The submucosal plexus transmits information from the epithelium to the enteric and central nervous systems.
What is the muscularis mucosa and what is its function?
It is a thin layer of smooth muscle that moves the villi in the GI tract.
What is the lamina propria and what does it contain?
The lamina propria contains blood vessels, nerve endings, and immune and inflammatory cells.
What are the functions of the epithelium in the GI tract?
The epithelium is involved in sensing the GI contents, secreting enzymes, absorbing nutrients, and excreting waste.
What are the components of the GI tract’s autonomic nervous system (ANS)?
*extrinsic nervous system: SNS and PSNS
*enteric nervous system.
What is the primary function of the extrinsic SNS in the GI tract?
It is primarily inhibitory and decreases GI motility.
How does the extrinsic PNS affect the GI tract?
It is primarily excitatory and activates GI motility.
What does the enteric nervous system control?
It independently controls motility, secretion, and blood flow within the GI tract.
What is the enteric system comprised of?
The myenteric plexus and submucosal plexus.
What functions are regulated by the submucosal plexus?
Absorption, secretion, and mucosal blood flow.
How do the myenteric and submucosal plexuses respond to stimulation?
They respond to both sympathetic and parasympathetic stimulation.
What can an Upper Gastrointestinal Endoscopy be used for?
Diagnostic or therapeutic purposes
Endoscope can be placed into the esophagus, stomach, pylorus, and duodenum.
What are some anesthesia challenges during an Upper Gastrointestinal Endoscopy?
Sharing the airway
performing the procedure outside of the main OR.
What are some anesthesia challenges during a Colonoscopy?
Patient dehydration due to bowel preparation and NPO (nil per os, nothing by mouth) status.
What does High Resolution Manometry (HRM) measure?
HRM measures pressures along the entire length of the esophagus.
What is HRM generally used to diagnose?
Motility disorders of the esophagus.
What is a GI series with ingested barium used for?
It is a radiologic assessment of swallowing function and GI transit.
How is a gastric emptying study conducted?
The patient fasts for at least 4 hours, then consumes a meal with a radiotracer, followed by continuous or frequent imaging for the next 1-2 hours.
What does small intestine manometry measure?
It measures contraction pressures and motility of the small intestine.
How are contractions evaluated during small intestine manometry?
They are evaluated during three periods: fasting, during a meal, and post-prandial, typically with 4 hours of fasting, then a meal, followed by 2 hours post-meal recording.
What does a lower GI series involve and what does it detect?
It involves the administration of a barium enema to outline the intestines on radiographs, allowing for the detection of colon and rectal anatomical abnormalities.
Into what categories are diseases of the esophagus grouped?
Anatomical
Mechanical
Neurologic
Although many disease states overlap
What are some anatomical causes of esophageal diseases?
Diverticula
hiatal hernia
changes associated with chronic acid reflux
What are mechanical causes of esophageal diseases?
Achalasia (failure of smooth muscle fibers to relax)
esophageal spasms
hypertensive lower esophageal sphincter (LES).
What can neurologic causes of esophageal diseases be a result of?
stroke
vagotomy
hormone deficiencies.
What are the most common symptoms of esophageal disease?
Dysphagia, heartburn, and GERD (Gastroesophageal Reflux Disease).
What is dysphagia and how is it classified?
Dysphagia is difficulty swallowing, which may be oropharyngeal or esophageal.
What is a common cause of oropharyngeal dysphagia?
It’s commonly seen after head and neck surgeries.
How can esophageal dysphagia be categorized based on physiology?
(mechanical vs. esophageal)
- Esophageal dysmotility: Symptoms occur with both liquids and solids.
- Mechanical esophageal dysphasia: Symptoms only occur with solid food.
What is GERD and what are its common symptoms?
GERD is the effortless return of gastric contents into the pharynx, often causing heartburn, nausea, and a sensation of a “lump in the throat.”
What is achalasia?
Achalasia is a neuromuscular disorder of the esophagus characterized by inadequate LES tone leading to outflow obstruction, and a dilated, hypomobile esophagus.
What causes achalasia?
The loss of ganglionic cells in the esophageal myenteric plexus, absence of inhibitory neurotransmitters of the LES, and unopposed cholinergic LES stimulation preventing relaxation.
What are the symptoms of achalasia?
Dysphagia, regurgitation, heartburn, and chest pain.
How is achalasia diagnosed?
With esophageal manometry and/or esophagram.
What are the three classes of achalasia and how do they respond to treatment?
- Type 1: Minimal esophageal pressure, responds well to myotomy.
- Type 2: Entire esophagus pressurized; responds well to treatment and has the best outcomes.
- Type 3: Esophageal spasms with premature contractions; has the worst outcomes.
What medications are used for achalasia treatment?
Nitrates and calcium channel blockers (CCBs) to relax the lower esophageal sphincter (LES).
What endoscopic treatment is used for achalasia?
Endoscopic botox injections to temporarily relax the LES.
Which non-surgical treatment is most effective for achalasia?
Pneumatic dilation.
What is considered the best surgical treatment for achalasia?
Laparoscopic Heller Myotomy.
What is a Peri-oral Endoscopic Myotomy (POEM) and its risks?
POEM is an endoscopic division of LES muscle layers with a 40% risk of developing pneumothorax or pneumoperitoneum.
What is the anesthesia consideration for patients with achalasia?
Patients are at increased risk for aspiration; Rapid Sequence Induction (RSI) or awake intubation is indicated.
What are Diffuse Esophageal Spasms and where do they commonly occur?
Spasms that usually occur in the distal esophagus and are likely due to autonomic dysfunction.
Who is more commonly affected by Diffuse Esophageal Spasms?
the elderly.
How is Diffuse Esophageal Spasm diagnosed?
Diagnosed on an esophagram.
What can the pain from Diffuse Esophageal Spasms mimic?
Pain can mimic angina.
What are some treatments for Diffuse Esophageal Spasms?
Treatments include nitroglycerin (NTG), antidepressants, and phosphodiesterase inhibitors (PD-Is).
What are Esophageal Diverticula?
Outpouchings in the wall of the esophagus.
What is Pharyngoesophageal (Zenker) Diverticulum and a symptom associated with it?
A type of esophageal diverticulum associated with bad breath due to food retention.
What might cause Midesophageal Diverticula?
May be caused by old adhesions or inflamed lymph nodes.
What condition may patients with Epiphrenic (supradiaphragmatic) Diverticula also experience?
Patients may also experience achalasia.
What is a Hiatal Hernia?
A herniation of the stomach into the thoracic cavity through the esophageal hiatus in the diaphragm.
What can cause a Hiatal Hernia?
It can be caused by weakening in the anchors of the gastroesophageal (GE) junction to the diaphragm.
What are common symptoms associated with a Hiatal Hernia?
It may be asymptomatic but is often associated with GERD (Gastroesophageal Reflux Disease).
How does esophageal cancer typically present?
With progressive dysphagia and weight loss.
Why is the survival rate poor for esophageal cancer?
Because the abundant lymphatics lead to lymph node metastasis.
What are the risk factors for esophageal cancer?
GERD
Barrett’s esophagus
obesity.
What types of cancer account for esophageal cancers?
adenocarcinomas (most common)
Squamous cell carcinoma.
How can an esophagectomy be performed?
It may be performed transthoracically, transhiatally, or using minimally invasive techniques.
What is a common complication of esophagectomy and its prognosis?
High risk of recurrent laryngeal nerve injury, with about 40% resolving spontaneously.
What nutritional status is common in patients preoperatively and post-esophagectomy?
Patients often present malnourished before the operation and may remain so for many months after.
What complications may present if there is a history of chemotherapy or radiation prior to esophagectomy?
Pancytopenia and dehydration.
What is a long-term risk for patients after esophagectomy?
They are at a very high risk for aspiration for life.
What causes GERD?
Incompetence of the gastroesophageal junction, leading to reflux.
What are common symptoms of GERD?
Heartburn, dysphagia, and mucosal injury.
Prevalence of GERD in adults?
Occurs in 15% of adults.
What does reflux content include in GERD?
Hydrochloric acid (HCl), pepsin, pancreatic enzymes, and bile.
How is bile reflux associated with Barrett metaplasia and adenocarcinoma?
Bile reflux is associated with Barrett metaplasia and an increased risk of adenocarcinoma.
What are the three mechanisms of gastroesophageal incompetence in GERD?
- Transient lower esophageal sphincter (LES) relaxation, elicited by gastric distention.
- LES hypotension (normal LES pressure is 29 mmHg; average GERD pressure is 13 mmHg).
- Autonomic dysfunction of the GE junction.