GI assessment - Exam 4 Flashcards
1
Q
The GI tract constitutes approximately what percent of the total body mass?
What are it’s main functions?
A
5%
motility, digestion, absorption, excretion, and circulation
2
Q
From outermost to innermost, list the layers of the GI system
A
the serosa, longitudinal muscle layer, circular muscle layer, submucosa, and mucosa
3
Q
Within the mucosa of the GI system, list the outermost to innermost layers
List each function of these layers
A
muscularis mucosae: move the villi
lamina propria: contains blood vessels, nerve endings, immune cells
epithelium: GI contents are sensed, enzymes are secreted, nutrients absorbed
4
Q
The _____ muscle layer contracts to shorten the length of the intestinal segment
The ____ muscle layer contracts to decrease the diameter of the intestinal lumen
A
Longitudinal
Circular
These two layers work together to propagate gut motility
5
Q
The GI tract is innervated by the ____ and consists of what 2 things?
A
Autonomic nervous system
- extrinsic nervous system
- enteric nervous system
6
Q
The extrinsic nervous system of the GI tract has both ____ & ____ components. What is the difference in these?
A
SNS/PNS
- The extrinsic SNS is primarily inhibitory anddecreases GI motility
- The extrinsic PNS is primarily excitatory and activates GI motility
7
Q
The enteric nervous system is the ____ nervous system which controls what 3 things?
What does it consist of?
A
Independent
- motility
- secretions
- blood flow
myenteric plexus
submucosal plexus
8
Q
What does the celiac plexus innervate?
A
Innervates the proximal GI organs to the transverse colon
9
Q
What does the hypogastric plexus innervate?
A
Innervates the descending colon and distal GI tract
10
Q
The celiac plexus can be blocked via different approaches, including:
A
Trans-crural
Intraoperative
endoscopic ultrasound-guided
peritoneallavage
11
Q
Myenteric plexuslies betweenthe ____ muscle layers and regulatesthe ____ muscle
A
Smooth (for both)
12
Q
Submucosal plexustransmits info from the _____ to the _____and _____ nervoussystems
A
epithelium
enteric and central
13
Q
The enteric system is composed of what?
A
myenteric plexus
submucosal plexus
Both of theseplexuses respond to SNS and PNSstimulation
14
Q
What does the myenteric plexus do?
A
controls motility, carried out by enteric neurons,interstitial cells of Cajal (aka ICC cells, GI pacemakers), andsmooth musclecells
15
Q
What does the submucosal plexus do?
A
controls absorption, secretion, and mucosal bloodflow
16
Q
GI diagnostic procedures include
A
Upper Gastrointestinal Endoscopy
Colonoscopy
High Resolution Manometry (HRM)
GI series with ingested barium
Gastric emptying study
Small intestine manometry
lower GI series
17
Q
What is an upper GI endoscopy?
Anesthesia challenges?
A
Endoscope placed into esophagus, stomach, pylorus, and duodenum
- sharing airway with endoscopist
- usually done without ETT, most closely manage airway
- Procedure performed outside of the main OR (limited equipment & supplies)
18
Q
What is a colonoscopy?
Anesthetic challenges?
A
May be diagnostic or therapeutic/interventional; may be done with or w/o anesthesia
- Pt dehydration d/t bowel prep & NPO status
19
Q
What is a High Resolution Manometry (HRM)?
A
a pressure cathetermeasures pressuresalong entire esophageal length
- generally used to dx motility disorders
20
Q
What is a GI series with ingested barium?
A
radiologic assessment of swallowing function and GI transit
21
Q
What is a gastric emptying study?
A
pt fasts for 4+ hrs, then consumes a meal with a radiotracer. Frequent imaging for the next 1-2 hrs
22
Q
What is a small intestine manometry?
A
catheter measures contraction pressures andmotility of the small intestine
- evaluatescontractions during three periods: fasting, during a meal, and post-prandial
- Abnormalresults are grouped into myopathic and/or neuropathic causes
23
Q
What is a lower GI series?
A
Barium enema outlines the intestines and it is visible on radiograph, allowing for detection of colon/rectal abnormalities
24
Q
Diseases of the esophagus are grouped into:
A
Anatomical
Mechanical
Neurologic
although many disease states overlap!
25
What are examples of anatomical esophageal disease?
diverticula, hiatal hernia, and changes assoc w/ chronic acid reflux
26
What are examples of mechanical esophageal disease?
achalasia, esophageal spasms, and a hypertensive LES
27
What are examples of neurologic esophageal disease?
neurologic disorders such as stroke, vagotomy, or hormone deficiencies
28
What are the most commons symptoms of esophageal disease?
dysphagia, heartburn, GERD
29
What is dysphagia?
When are these common?
difficulty swallowing, may be oropharyngeal or esophageal
Oropharyngeal: common after head & neck surgeries
Esophageal: classified based on physiology
- Esophageal dysmotility: sx occur w/ both liquids & solids
- Mechanical esophageal dysphasia: sx only occur w/solid food
30
What is GERD?
effortless return of gastric contents into pharynx; Incompetence of the gastro-esophageal junction
- Heartburn, nausea, “lump in throat”
31
What is achalasia?
neuromuscular disorder of the esophagus creating an outflow obstruction d/t inadequate LES tone and a dilated hypomobile esophagus
32
Explain achalasia theoretical cause
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
33
Symptoms of achalasia
dysphagia, regurgitation, heartburn, chest pain
34
Long term achalasia is associated with what?
How is diagnosis made?
increased rx of esophageal cancer
- esophageal manometry and/or esophagram
35
What are the 3 classes of achalasia?
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
36
Achalasia treatment
** All treatments are palliative**
- Meds: nitrates & CCBs to relax LES
- endoscopic botox
- Pneumatic dilation * most effective nonsurgical tx
- Laparoscopic Hellar Myotomy *best surgical tx
- Peri-oral endoscopic myotomy (POEM)- endoscopic division of LES muscle layers
- Esophagectomy- only considered in the most advanced dz states
## Footnote
40% pts who get POEM develop pneumothorax or pneumoperitoneum
37
Pts with achalasia are at increase risk for what?
Aspiration
38
What is an esophageal spasm?
Spasms that usually occur in distal esophagus; likely d/t autonomic dysfunction
- More common in elderly
- Pain mimics angina
39
Treatment and diagnosis of esophageal spasm
Dx on esophagram
Tx: NTG, antidepressants, PD-I's
40
What is Esophageal Diverticula?
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
## Footnote
All are aspiration risk!
41
What is a hiatal hernia?
Herniation of stomach into thoracic cavity, occurs through the esophageal hiatus in the diaphragm
42
Hiatal hernias are caused by?
weakening in connective tissues that anchor the GE junction to the diaphragm
- may be asymptomatic
43
Esophageal cancer affections ___ in the US and presents with what?
4-5/100,000 ppl in US
progressive dysphagia and weight loss
44
Esophageal cancer has a poor survival rate. Why?
abundant lymphatics leads to lymph node metastasis
45
Most esophageal cancers are what type?
These are related to what 3 things?
What are the rest of esophageal cancers accounted to?
adenocarcinomas, located in lower esophagus
- GERD, Barretts, Obesity
Squamos cell carcinoma
46
Esophagectomy may be performed what 3 ways?
transthoracic, transhiatal, or minimally invasive
- may be curative or palliative
47
Esophagectomy has a high risk of what?
recurrent laryngeal nerve injury
48
Gastric reflux contents may include
HCL, pepsin, pancreatic enzymes, bile
49
Bile reflux is associated with what?
Barrett metaplasia & adenocarcinoma
50
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
51
Treatment of GERD
avoidance of trigger foods
Meds: Antacids, H2 blockers, PPIs
Surgery: Nissen Fundoplication, Toupet, LINX
52
Preop interventions for 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
- Aspiration precautions!
53
Factors that increase intra-op aspiration risk (12 total)
Emergent surgery
Full Stomach
Difficult airway
Inadequate anesthesia depth
Lithotomy
Autonomic Neuropathy
Gastroparesis
DM
Pregnancy
↑ Intraabdominal pressure
Severe Illness
Morbid Obesity
54
What is the stomachs purpose?
the stomach serves as a reservoir for food, mixes and breaks down food to form chyme, and empties into the small intestine
55
Solids must be broken down into ____ mm particles before entering the duodenum
1-2
56
Explain neural regulation for the stomach
The motility of the stomach is controlled by intrinsic and extrinsic neural regulation
- PNS stimulates the vagus nerve to increase the number and force of contractions
- SNS stimulation to the splanchnic nerve inhibits these contractions
57
Explain how neurohormonal control also modulates GI movement
gastrin & motilin increase the strength and frequency of contractions
gastric inhibitory peptide inhibits contractions
58
What is the most common cause of non-variceal upper GI bleed?
Prevalence?
Peptic ulcer disease
Lifetime prevalence= 10% women, 12% men; 15,000 deaths per year
59
Petpic ulcer disease may be associated with what bacteria?
Symptoms?
Helicobacter Pylori
Sx: burning epigastric pain exacerbated w/fasting and improved w/meals
60
What do you see with perforation in peptic ulcer disease?
sudden/severe epigastric pain c/b acidic secretions into peritoneum
61
Mortality in peptic ulcer disease is d/t what 2 things?
shock or perforation >48h
62
What is gastric outlet obstruction?
Acute obstructions c/b edema & inflammation in pyloric channel at the beginning of duodenum
- onset may be acute or slow
63
Symptoms and treatment of gastric outlet obstruction
Sx: Recurrent vomiting, dehydration & hyperchloremic alkalosis
Tx: NGT, IV hydration; Normally resolves in 72h
64
Chronic obstructions or stenosis (gastric outlet obstruction) can be caused by what 2 things?
repetitive ulceration & scarring
65
Gastric ulcers are normally caused by what?
excessive NSAIDS, H. Pylori, ETOH
66
Treatment of gastric ulcers?
What is the exception?
Tx: Antacids, H2 blockers, PPIs, prostaglandin analogues, cytoprotective agents
H. Pylori tx=Tripple therapy (2 abx + PPI) x 14 days
67
Classification of gastric ulcer chart
68
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
69
Symptoms of Zollinger Ellison syndrome
peptic ulcer dz, erosive esophagitis, diarrhea
- Pts have ↑ gastric volume, e-lyte imbalances, & endocrine abnormalities
70
Who do you usually see Zollinger Ellison syndrome in?
Occurs in 0.1-1% of PUD pts
M > F; Most commonly btw ages 30-50
71
Tx of Zollinger Ellison syndrome
PPIs and surgical resection of gastrinoma
72
Preop considerations of Zollinger Ellison syndrome
Correct lytes,↑gastric pH w/meds, RSI
73
What is the major function of small intestine?
to circulate contents and expose them to the mucosal wall to maximize absorption
74
What is segmentation in the small intestine?
The circular and longitudinal muscle layers coordinate to achieve segmentation
- Segmentation occurs when two nearby areas contract and isolate a segment to hold the contents in place long enough to be absorbed into the circulation
- Segmentation is controlled mainly by the enteric nervous system with motility controlled by the extrinsic nervous system
75
Reversible causes of small bowel dysmotility
- mechanical obstruction such as hernias, malignancy, adhesions, and volvuluses
- bacterial overgrowth leading to alterations in absorptive function
- ileus, electrolyte abnormalities, and critical illness
76
Non-reversible causes can be classified as ____ or _____
What are examples of these causes?
Structural or neuropathic
Structural: scleroderma, connective tissue disorders, IBD
Neuropathic: pseudo-obstruction c/b intrinsic and extrinsic nervous systems dysfunction
- only produce weak, uncoordinated contractions
- leads to bloating, nausea, vomiting, and abdominal pain
77
Large intestine jobs
acts as a reservoir for waste and indigestible material before elimination and it extracts remaining electrolytes and water
78
What are giant migrating complexes?
Giant migrating complexes serve to produce mass movements across the large intestine
- In the healthy state, these complexes occur approximately 6-10x a day
- the colon also exhibits these!
79
Colonic dysmotility manifests with what 2 primary symptoms?
What are the most common diseases associated with this?
altered bowel habits and/or intermittent cramping
IBS and IBD
80
What is ulcerative colitis?
Mucosal dz of part or all of the colon
- in severe cases, the mucosa is hemorrhagic, edematous, and ulcerated
81
Symptoms of UC
diarrhea, rectal bleeding, crampy abdominal pain, N/V, fever, weight loss
82
Labs in UC pts
may have ↑plts,↑erythrocyte sedimentation rate,↓H&H,↓albumin
83
In IBD, hemorrhage requiring ___ units of blood within 24-48 hrs warrants what?
6+ units
surgical colectomy
84
_______ is a complication of IBD triggered by e-lyte disturbance
Toxic megacolon
- About ½ cases resolve, ½ require colectomy
- Colon perforation is a dangerous complication- mortality rate 15%
85
What is Crohn's?
Acute or chronic inflammatory process that may affect any/all of the bowel
- Most common site is the terminal ileum, usually presenting w/ileocolitis and RLQ pain & diarrhea
- Persistent inflammation gradually progresses to fibrous narrowing & stricture formation
- Diarrhea decreases and is replaced by chronic bowel obstruction
- Extensive inflammation leads to loss of absorptive surfaces, resulting in malabsorption
86
Symptoms of Crohn's
weight loss, fear of eating, anorexia, diarrhea
1/3 Crohn’s pts have an additional sx s/a arthritis, dermatitis, kidney stones
87
Medical treatment of IBD
- 5-Acetylsalicylic acid (5-ASA)- mainstay for IBD *antibacterial & anti-inflammatory
- PO/IV Glucorticoids during flares
- Antibiotics: Rifaximin, Flagyl, Cipro
- Purine analogues
88
Surgical treatment of IBD
- Last resort. Resected segment should be as conservative as possible.
- Small intestine resection should be limited to <1/2 length
- >2/3 SI resection leads to “short bowel syndrome", requiring TPN
89
Where do most carcinoid tumors originate from?
GI tract
90
What do carcinoid tumors secrete?
peptides & vasoactive substances: gastrin, insulin, somatostatin, motilin, neurotensin, tachykinins, glucagon, serotonin, other biological actives
91
Symptoms of carcinoid tumors
flushing, diarrhea, HTN/HoTN, bronchoconstriction
- May acquire right heart endocardial fibrosis
- Left heart generally more protected as the lungs clear some of the vasoactive substances
92
Diagnosis and treatment of carcinoid tumors
Dx: urinary or plasma serotonin levels, CT/MRI
Tx: avoid serotonin-triggers, serotonin antagonists & somatostatin analogues
93
Why has incidence of acute pancreatitis increased 10 fold since 1960s?
Likely d/t ETOH + better diagnostic
94
Autodigestion is normally prevented by:
Proteases packaged in precursor form
Protease inhibitors
Low intra-pancreatic calcium, which decreases trypsin activity
Failure of any of these mechanisms can trigger pancreatitis
95
What are the two most common causes of acute pancreatitis?
Gallstones and ETOH
## Footnote
- Gallstones obstruct ampulla of vater, causing pancreatic ductal HTN
- Pancreatitis is also seen in immunodeficiency syndrome, hyperparathyroidism/↑Ca²
96
Sx and hallmark labs of acute pancreatitis
Sx: excruciating epigastric pain that radiates to back, N/V, abd distention, steatorrhea, ileus, fever, tachycardia, HoTN
↑serum amylase & lipase
97
Imaging for acute pancreatitis?
contrast CT or MRI, endoscopic US (EUS)
98
Complications and treatment of acute pancreatitis
Complications: 25% experience serious complications s/a shock, ARDS, renal failure, necrotic pancreatic abscess
Tx: Aggressive IVF, NPO to rest pancreas, enteral feeding (preferred over TPN), opioids, ERCP
## Footnote
ERCP is used for stone removal, stent placement, sphincterotomy, hemostasis
99
What is more common, upper or lower GI bleeds?
>___% blood loss leads to HoTN and tachycardia
Upper
>25%
100
Melena indicates bleed is above what?
Cecum
101
What is the therapeutic procedure of choice for GI bleeds?
Lat resort treatment?
EGD
Mechanical balloon tamponade
102
Causes of lower GI bleeding
diverticulosis, tumors, colitis
103
What is performed for lower GI bleeds?
Persistent bleeding warrants what?
Colonoscopy
Angiography and embolic therapy
104
What is an ileum?
characterized by massive dilation of the colon without mechanical obstruction
- Loss of peristalsis leads to distention of the colon
105
Ileum may be caused by?
e-lyte disorders, immobility, excessive narcotics, anticholinergics
## Footnote
Also thought to be due to neural-input imbalance of excessive SNS stimulation along with inadequate PNS input to the colon
106
Treatment of ileum
Restore e-lyte balance, hydrate, mobilize, NG suction, enemas
Neostigmine 2-2.5mg over 5 min
107
If an ileus is left untreated, what can occur?
ischemia and perforation
108
Inhibition of GI activity is directly proportional to what?
the amount of norepinephrine secreted from SNS stimulation, so the higher anxiety = higher GI inhibition
109
Volatile anesthetics may depress what 3 things of GI activity?
electrical, contractile, and propulsive
110
The ______ is the first part of the GI tract to recover, followed by the _____ in approximately 24 hours and then the ____ 30 to 40 hrs postop
Small intestine
Stomach
Colon
111
Nitrous oxide is 30x more soluble than ____ in the blood and will diffuse into gas-containing cavities from the blood faster than the ____ can diffuse out
Nitrogen (for both)
112
GI distention correlates with what?
with the pre-existing amount of gas in the bowel, as well as the duration and concentration of nitrous administered
113
Nitrous oxide should be avoided when?
in lengthy abdominal surgeries or when the bowel is already distended
114
Why does GI motility remain intact with NMBs?
NMBs only affect skeletal muscle
115
________ will increase PNS activity and bowel peristalsis by increasing the frequency & intensity of contractions
Neostigmine (AchE-I)
116
Cholinergic activity from neostigmine is partially offset by what?
concurrent administration of an anticholinergic (glycopyrrolate or atropine), which counteract the bradycardia associated with neostigmine
117
______ are known to cause reduced GI motility and constipation
What receptors does this stimulate?
Opiods
- mu, delta, and kappa receptors
118
There is a high density of peripheral mu-opioid receptors in the:
Activation of the mu-receptors causes what?
myenteric and submucosal plexuses
delayed gastric emptying and slower GI transit
119
Other adverse events on GI system from opiods
nausea, anorexia, delayed digestion, abdominal pain, and constipation
120
