Exam 4 - Gastrointestinal Assessment Flashcards
The GI system constitutes ____ of the body mass
5%
The main functions of the GI system include:
motility, digestion, absorption, excretion, and circulation
From outermost to innermost, the GI layers are:
serosa, longitudinal muscle layer, circular muscle layer, submucosa, and mucosa
Within the mucosa, the outermost to innermost layers are:
muscularis mucosae, lamina propria, and epithelium
What is the function of the muscularis mucosa?
Move the villi
What is contained within the lamina propria?
Contains blood vessels, nerve endings, and immune cells
What happens within the epithelium of the mucosa?
- GI contents are sensed
- Enzymes are secreted
- Nutrients are absorbed
What is the purpose of the longitudinal muscle layer?
The circular muscle layer?
- Longitudinal muscle layer - contracts to shorten the length of the intestinal segment
- Circular muscle layer - contracts to decrease the diameter of the intestinal lumen
- Both layers work together to promote motility
This innervates the proximal GI organs to the transverse colon?
Celiac plexus
What innervates the descending colon and distal GI tract?
Hypogastric plexus
How can the celiac plexus be blocked?
- Trans-crural
- Intraoperative
- Endoscopic ultrasound-guided
- Peritoneallavage
What nerve lies between the smooth muscles layers of the intestines?
Myenteric plexus
What nerve transmits information from the epithelium to the eneteric and central nervous system?
Submucosal plexus
The GI tract is innervated by the ____ , which consists of the ____ and ____
- ANS
- Extrinsic nervous system
- Enteric nervous system
What are the components of the extrinsic nervous system?
SNS and PNS components
* The extrinsic SNS is primarily inhibitory anddecreases GI motility
* The extrinsic PNS is primarily excitatory and activates GI motility
The enteric nervous system is the ____ nervous system and includes ____ and ____ innervations
- Independent
- Myenteric
- Submucosal
What does the myenteric plexus control?
Motility via enteric neurons, interstitial cells of Cajal (ICC cells, pacemaker cells), and smooth muscle cells
The submucosal layer controls:
Absorption, secretion, and mucosal blood flow
The myenteric and submucosal plexus respond to what stimulation?
Both PNS and SNS
What are the anesthesia challenges with an EGD?
- Sharing airway with endoscopist
- Usually done without ETT, must closely manage airway
- Procedure performed outside of the main OR (limited equipment & supplies)
Anesthesia challenges for a colonoscopy?
Pt is dehydrated d/t bowel prep and NPO status
What test uses a pressure catheter to diagnose motility disorders?
High Resolution Manometry (HRM)
What test is used to assess swallowing function radiologically?
Barium GI series
How does a gastric emptying study work?
Pt fasts for 4 hours, then consumes a meal with a radiotracer - then completes frequent imaging withing the next 1-2 hours
What does the small intestine manometry test evaluate?
How are abnormal results grouped?
- Evaluatescontractions during three periods: fasting, during a meal, and post-prandial
- Myopathic and or neuropathic
What test allows for radiographic evaluation of the colon/rectum with the use of barium?
Lower GI series
What are the anatomical esophageal diseases?
- diverticula
- hiatal hernia
- changes assoc w/ chronic acid reflux
What are the mechanical esophageal diseases?
- achalasia
- esophageal spasms
- hypertensive LES
What are the neurological esophageal diseases?
- stroke
- vagotomy
- hormone deficiencies
What are the most common symptoms of espohageal disease?
- Dysphagia
- Heartburn
- GERD
What are esophageal dysmotility and mechanical esophageal dysphasia?
- Esophageal dysmotility: sx occur w/ both liquids & solids
- Mechanical esophageal dysphasia: sx only occur w/solid food
What is achalasia?
neuromuscular disorder of the esophagus creating an outflow obstruction d/t inadequate LES tone and a dilated hypomobile esophagus
What is the patho of achalasia?
- Theoretically, c/b loss of ganglionic cells of the esophageal myenteric plexus
- Followed by absence of LES inhibitory neurotransmitters
- Unopposed cholinergic LES stimulation (LES can’t relax)
- Esophageal dilation with food unable to move forward
Symptoms of achalasia?
dysphagia, regurgitation, heartburn, chest pain
What is long-term achalasia associated with?
What are the 3 classes?
- Increased risk of esophageal cancer
- Type 1: minimal esophageal pressure, responds well to myotomy
- Type 2: entire esophagus pressurized; responds well to treatment, has best outcomes
- Type 3: esophageal spasms w/premature contractions; has worst outcomes
Treatments for achalasia?
Which one is most effective surgical and nonsurgical option?
All treatments are palliative, not curative
- CCB and nitrates to relax LES
- Endoscopic botox
- Pneumatic dilation - most effective non surgical
- Laproscopic Hellar Myotomy - most effective surgical
- Perioral endoscopic myotomy (POEM) - division of muscle layers, high risk of pneumo
- Esophagectomy - last option
What esophageal disorder can mimic angina?
Treatments?
Esophageal spasms
Tx: NTG, antidepressants, PDI’s
What is an esophageal diverticula and the different types?
Outpouchings in the wall of the esophagus
Pharyngoesophageal (Zenker diverticulum): bad breath d/t food retention
Midesophageal: may be caused by old adhesions or inflamed lymph nodes
Epiphrenic (supradiaphragmatic): pts may experience achalasia
What disorder is caused by weakend connective tissues that anchor the GE junction to the diaphragm?
Hiatal hernia
What are the primary and secondary types of esophageal cancers?
- Adenocarcinomas
- Squamos Cell carinoma
What procedure carries a high risk of recurrent laryngeal nerve injury?
Anesthesia concerns?
Esophagectomy
- Malnutrition
- Chemo/radiation = pancytopenia and dehydration
Contents of reflux?
- HCL
- pepsin
- pancreatic enzymes
- bile
Bile reflux is associated with ?
- Barrest metaplasia
- Adneocarinoma
What are the 3 mechanisms of GE incompetence?
- Transient LES relaxation, elicited by gastric distention
- LES hypotension (normal LES pressure 29mmHg, avg GERD pressure 13 mmHg)
- Autonomic dysfunction of GE junction
Treatments for GERD?
- avoidance of trigger foods
- Meds: Antacids, H2 blockers, PPIs
- Surgery: Nissen Fundoplication, Toupet, LINX
Preop medications for pts with GERD?
- Cimetidine, Ranitidine- ↓acid secretion & ↑ gastric pH
- PPI’s generally given night before and morning of
- Sodium Citrate- PO nonparticulate antacid
- Metoclopramide- gastrokinetic; often reserved for diabetics, obese, pregnant
How does PNS and SNS stimulation effects the stomach?
- PNS stimulates the vagus nerve to increase the number and force of contractions
- SNS stimulation to the splanchnic nerve inhibits these contractions
What are the neurohormonal controls over GI movement?
- gastrin & motilin increase the strength and frequency of contractions
- gastric inhibitory peptide inhibits contractions
What is the most common cause of non-variceal upper GI bleeding?
Peptic Ulcer Disease
Symptoms of PUD?
Major adverse effect?
- Burning epigastric pain exacerbated w/fasting and improved w/meals
- Perforation
What bacteria is associated with PUD?
Helicobacter Pylori
Symptoms and treatments for gastric outlet obstruction?
- Sx: Recurrent vomiting, dehydration & hyperchloremic alkalosis
- Tx: NGT, IV hydration; Normally resolves in 72h
Types of gastric ulcers?
H. pylori treatment?
Tripple therapy (2abx+ PPI) x 14 days
What is Zollinger Ellison syndrome?
Non B cell pancreatic tumor (gastrinoma), causing gastrin hypersecretion
Gastrin stimulates gastric acid secretion. Gastric acid normally inhibits further gastrin release (neg feedback)
This feedback loop is absent in ZE syndrome
More common in men than women
Common abnormalities with ZE syndrome?
Treatments?
Pts have ↑ gastric volume, e-lyte imbalances, & endocrine abnormalities
Tx: PPIs and surgical resection of gastrinoma
Major function of the small intestines?
Circulate contents and expose them to the mucosal wall to maximize absorption
What is segmentation?
What controls it?
- When two nearby areas contract and isolate a segment to hold the contents in place long enough to be absorbed into the circulation
- Controlled mainly by the enteric nervous system with motility controlled by the extrinsic nervous system
What are the 2 classes of nonreversible small bowel dysmotility?
What disorders are included in each?
Structural: scleroderma, connective tissue disorders, IBD
Neuropathic:pseudo-obstruction
Where are giant migrating complexes found? What is their function?
- The colon
- Giant migrating complexes serve to produce mass movements across the large intestine
- In the healthy state, these complexes occur approximately 6-10x a day
How does colonic dysmotility present?
Altered bowel habits and or intermittent cramping
Patho of IBD?
What is included in IBD?
- contractions are suppressed due to inflammation, but the giant migrating complexes remain
- The increased frequency of giant migrating complexes further compresses the inflamed mucosa, which can lead to significant erosions and hemorrhage
- Includes Chrones and UC
What are the1st and 2nd most common inflammatory diseases?
- Rheumatoid arthritis
- IBD
What is Ulcerative Colitis?
Symptoms?
Lab findings?
- Mucosal disease of part of all of the colon
- Causes diarrhea, rectal bleeding, crampy abdominal pain, N/V, fever, weight loss
- Labs: may have ↑plts,↑erythrocyte sedimentation rate,↓H&H,↓albumin
When do UC patients require surgery?
- Hemmorhage requiring 6 or more units in 24 hours
- Toxic megacolon
Patho of Chron’s disease?
- Acute or chronic inflammatory process that may affect any/all of the bowel
- Most common site is the terminal ileum
- Inflammation causes fibrous narrowing and strictures → chronic bowel obstruction
What additional symptoms may Chron’s patients have?
- Arthritis
- Dermatitis
- Kidney stones
Medical treatments for IBD?
- 5-Acetylsalicylic acid (5-ASA)- mainstay for IBD antibacterial & anti-inflammatory
- PO/IV Glucorticoids during flares
- Antibiotics: Rifaximin, Flagyl, Cipro
- Purine analogues
Surgical considerations for IBD?
- Should be last resort
- Should not resect more than 2/3 of the small intestine to prevent short bowel syndrome
Where do most carcinoid tumors originate?
What do they secrete?
From the GI tract in any area
Secretes peptides and vasoactive substances
What is carcinoid syndrome?
Symptoms?
- Lg amts of serotonin & vasoactive substances reach systemic circulation
- Sx: flushing, diarrhea, HTN/HoTN, bronchoconstriction, right heart endocardial fibrosis
Tx and preop conerns for carcinoid tumors?
Tx: avoid serotonin-triggers, serotonin antagonists & somatostatin analogues
Preop: Octreotide before surgery and prior to tumor manipulation to attenuate volatile hemodynamic changes
Why has pancreatitis increased since 1960s?
Increased alcholism and better diagnostics
How is normal autodigesteion prevented in the pancreas?
- Proteases packaged in precursor form
- Protease inhibitors
- Low intra-pancreatic calcium, which decreases trypsin activity
Common causes of pancreatitis?
- Gallstones
- EtOH
- Immunodeficency syndrome → Hyperparathyroidism (increased Ca++)
Hallmark labs in pancreatitis?
↑serum amylase & lipase
Serious complications of pancreatitis?
Treatments?
Complications: shock, ARDS, renal failure, necrotic pancreatic abscess
Tx: Aggressive IVF, NPO to rest pancreas, enteral feeding (preferred over TPN), opioids, ERCP
TPN associated w/greater risk of infectious complications
____ blood loss will lead to HoTN & tachycardia
Orthostatic HoTN normally indicates HCT ____
____ indicates bleed is above the cecum (where SI meets colon)
> 25% blood loss will lead to HoTN & tachycardia
Orthostatic HoTN normally indicates HCT < 30%
Melena indicates bleed is above the cecum (where SI meets colon)
Why is BUN elevated in GI bleeding?
Typically > 40 d/t absorbed nitrogen into bloodstream
Ileus treatments?
Restore e-lyte balance, hydrate, mobilize, NG suction, enemas
Neostigmine 2-2.5mg over 5 min
What can cause GI inhbition related to surgery?
Preop anxiety - increased SNS stimulation
Volatile anesthetics - depresses electrical, contractile, and propulsive GI activity
How does the GI tract recover from anesthesia?
small intestine → stomach (24 h) → colon (30-40h)
What should be avoided in lengthy abdominal surgeries?
Nitrous
What receptors cause delayed gastric emptying from opioids?
Mu receptors
