GI Flashcards
1
Q
What are the main functions of the GI tract?
A
Motility, digestion, absorption, excretion, and circulation
2
Q
List the layers of the GI tract from outermost to innermost.
A
- Serosa
- Longitudinal muscle layer
- Circular muscle layer
- Submucosa
- Mucosa
3
Q
What is the role of the longitudinal muscle layer in the GI tract?
A
Contracts to shorten the length of the intestinal segment
4
Q
What does the circular muscle layer do?
A
Contracts to decrease the diameter of the intestinal lumen
5
Q
What components make up the mucosa? (outermost to innermost)
A
- Muscularis mucosa
- Lamina propria
- Epithelium
6
Q
What is the function of the muscularis mucosa in the mucosa?
A
Moves the villi
7
Q
What does the lamina propria contain?
A
- Blood vessels
- Nerve endings
- Immune cells
8
Q
What happens in the epithelium of the mucosa?
A
where the GI contents are sensed, enzymes aresecreted,and nutrientsareabsorbed
9
Q
What is the primary nervous system that innervates the GI tract?
A
Autonomic nervous system
10
Q
What does the GI ANS consist of?
A
extrinsic nervous system
enteric nervous system
11
Q
What are the two components of the extrinsic nervous system?
A
- Sympathetic nervous system (SNS)
- Parasympathetic nervous system (PNS)
12
Q
What is the role of the extrinsic SNS in GI function?
A
Primarily inhibitory and decreases GI motility
13
Q
What is the role of the extrinsic PNS in GI function?
A
Primarily excitatory and activates GI motility
14
Q
What is the enteric nervous system?
A
An independent nervous system that controls motility, secretions, and blood flow
15
Q
What are the two plexuses of the enteric nervous system?
A
- Myenteric plexus
- Submucosal plexus
16
Q
What does the celiac plexus innervate?
A
Proximal GI organs to the transverse colon
17
Q
What does the hypogastric plexus innervate?
A
Descending colon and distal GI tract
18
Q
Through what approaches can the celiac plexus be blocked?
A
*Trans-crural
*Intraoperative
*endoscopic ultrasound-guided
*peritoneallavage
19
Q
What is the function of the myenteric plexus?
A
Regulates smooth muscle and controls motility, carried out by enteric neurons,interstitial cells of Cajal (aka ICC cells, GI pacemakers), andsmooth musclecells
20
Q
What does the submucosal plexus transmit?
A
Information from the epithelium to the enteric and central nervous systems that controls absorption, secretion, and mucosal bloodflow
21
Q
The myenteric and submucosal plexus respond to
A
both SNS and PNS stimulation
22
Q
What is an upper gastrointestinal endoscopy?
A
A procedure where an endoscope is placed into the esophagus, stomach, pylorus, and duodenum for diagnostic or therapeutic purposes
23
Q
What are anesthetic challenges with upper GI endoscopy?
A
*sharing airway with endoscopist
*usually done without ETT, most closely manage airway
*Procedure performed outside of the main OR (limited equipment & supplies)
24
Q
Does a colonoscopy require anesthesia and what are the anesthetic challenges?
A
No it doesn’t
Pt dehydration d/t bowel prep & NPO status
25
What is High Resolution Manometry (HRM) used for?
To diagnose motility disorders by measuring pressures along the esophagus
26
GI series with ingested barium:
radiologic assessment of swallowing function and GI transit
27
Gastric emptying study:
pt fasts for 4+ hrs, then consumes a meal with a radiotracer. Frequent imaging for the next 1-2 hrs
28
Small Intestine Manometry
Diagnostic tool that measures and evaluates contraction pressure and motility in the small intestine during fasting, during a meal, and post-prandial.
Abnormal results are grouped into myopathic and/or neuropathic causes
29
Lower Gi Series
Barium enema outlines the intestines and it is visible on radiograph, allowing for detection of colon/rectal abnormalities
30
What are the categories of esophageal disease?
Anatomical
Mechanical
Neurologic
31
Name Anatomical esophageal diseases
diverticula
hiatal hernia
changes assoc w/ chronic acid reflux
32
Name Mechanical Esophageal Disease
achalasia
esophageal spasms
a hypertensive LES
33
Neurologic Esophageal Diseases
neurologic disorders such as stroke, vagotomy, or hormone deficiencies
34
What are the most common symptoms of esophageal disease?
Dysphagia, heartburn, GERD
35
What is dysphagia?
difficulty swallowing, may be oropharyngeal or esophageal
36
When is oropharyngeal dysphagia commonly seen?
after head and neck surgeries
37
How is esophageal dysphagia characterized?
based on physiology
- Esophageal dysmotility: sx occur w/ both liquids & solids
- Mechanical esophageal dysphasia: sx only occur w/solid food
38
Define achalasia.
A neuromuscular disorder of the esophagus creating an outflow obstruction due to inadequate LES tone and a dilated hypomobile esophagus
39
Achalasia Symptoms
dysphagia, regurgitation, heartburn, chest pain because LES can't relax to allow food move forward
40
What is long term achalasia associated with?
esophageal cancer
41
What are the three classes of achalasia?
* Type 1: Minimal esophageal pressure
* Type 2: Entire esophagus pressurized
* Type 3: Esophageal spasms with premature contractions
42
What is the treatment for achalasia?
* Medications (nitrates, CCBs)
* Endoscopic botox injections
* Pneumatic dilation
* Laparoscopic Heller myotomy
* Peri-oral endoscopic myotomy (POEM)
* Esophagectomy in advanced cases
They are all palliative
43
What is the most effective nonsurgical and surgical treatment for Achalasia?
nonsurgical: Pneumatic dilation
surgical: Laparoscopic Hellar Myotomy
44
Anesthetic considerations for Achalasia patients
Pts are ↑rx for aspiration
RSI or awake intubation indicated
45
Risks with Peri-oral endoscopic myotomy (POEM)
40% develop pneumothorax or pneumoperitoneum
46
Characteristics and Treatment of esophageal spasms
Spasms that usually occur in distal esophagus; likely d/t autonomic dysfunction and more commonly seen in elderly with pain that mimics angina
Treated with: NTG, antidepressants, PD-I's
47
Esophageal Diverticula
outpouchings in the wall of the esophagus that can be pharyngoesophageal, midesophageal, and epiphrenic
All are aspiration risks-Removal of particles and RSI indicated.
48
What is GERD?
Gastroesophageal reflux disease characterized by the effortless return of gastric contents into the pharynx
*heartburn, nausea, "lump in throat"
49
Hiatal Hernia
Herniation of stomach into thoracic cavity, occurs through the esophageal hiatus in the diaphragm that is often associated with GERD, but may be asymptomatic
50
Esophageal Cancer
*Presents w/progressive dysphagia and weight loss
*Poor survival rate bc abundant lymphatics leads to lymph node metastasis
*Most are adenocarcinomas, located in lower esophagus
*These are r/t GERD, Barretts, Obesity
*Squamous cell carcinoma accounts for the rest of esophageal cancers
51
Esophagectomy Anesthetic Considerations
- High risk of recurrent laryngeal nerve injury
- Post-esophagectomy pts are very high aspiration risk for life
- Pts often malnourished preop, and many months after
52
What are the three mechanisms of gastroesophageal incompetence?
* Transient LES relaxation elicited by gastric distention
* LES hypotension (normal: 29mmHg, avg GERD: 13mmHg)
* Autonomic dysfunction of GE junction
53
Treatment for GERD
avoidance of trigger foods
Meds: Antacids, H2 blockers, PPIs
Surgery: Nissen Fundoplication, Toupet, LINX
54
GERD preop interventions
*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!-RSI indicated. Cricoid pressure has become controversial
55
What are factors that increase intraop aspiration risk?
Emergent surgery
Full Stomach
Difficult airway
Inadequate anesthesia depth
Lithotomy
Autonomic Neuropathy
Gastroparesis
DM
Pregnancy
↑ Intraabdominal pressure
Severe Illness
Morbid Obesity
56
How is the stomach controlled?
*PNS stimulates the vagus nerve to increase the number and force of contractions
*SNS stimulation to the splanchnic nerve inhibits these contractions
*Neurohormonal control also modulates GI movement through gastrin, motilin, and gastric inhibitory peptide
57
Gastric Outlet Obstruction
Acute obstructions c/b edema & inflammation in pyloric channel at the beginning of duodenum that is characterized by Recurrent vomiting, dehydration & hyperchloremic alkalosis
58
What is Zollinger Ellison Syndrome?
A non-B cell pancreatic tumor (gastrinoma) causing gastrin hypersecretion
59
Who is Zollinger Ellison Syndrome more commonly seen in?
M>F
ages 30-50
60
What are the primary functions of the small intestine?
* Circulate contents
* Expose contents to the mucosal wall for absorption
61
What is the role of segmentation in the small intestine and what is it controlled by?
To hold contents in place long enough for absorption into circulation mainly controlled by enteric nervous system
62
What are reversible causes of small bowel dysmotility?
* Mechanical obstruction
* Bacterial overgrowth
* Ileus
* Electrolyte abnormalities
* Critical illness
63
What are the nonreversible causes of the small intestines?
*Structural: scleroderma, connective tissue disorders, IBD
*Neuropathic: pseudo-obstruction c/b intrinsic and extrinsic nervous systems dysfunction
64
What is the primary function of the large intestine?
Acts as a reservoir for waste and extracts remaining electrolytes and water
65
Giant Migrating complexes
serve to produce mass movements across the large intestine that typically occur approximately 6-10x a day
66
What are the primary symptoms of colonic dysmotility?
* Altered bowel habits
* Intermittent cramping
67
What does inflammatory bowel disease (IBD) include?
* Ulcerative colitis (UC)
* Crohn's disease
68
What is the most common cause of non-variceal upper GI bleeding?
Peptic ulcer disease
69
What is the treatment for H. Pylori infection?
Triple therapy (2 antibiotics + PPI) for 14 days
70
What are gastric ulcers normally caused by?
excessive NSAIDS, H. Pylori, ETOH
71
Which gastric classes are characterized by acid hypersecretion?
II, III
72
Which gastric class is normally seen with NSAID use?
Type V
73
Fill in the blank: The stomach serves as a reservoir for food, mixes and breaks down food to form _______.
[chyme]
74
True or False: The small intestine is primarily responsible for the absorption of nutrients.
True
75
What are the primary symptoms of colonic dysmotility?
Altered bowel habits and/or intermittent cramping
76
What are the most common diseases associated with colonic dysmotility?
IBS and IBD
77
In Inflammatory Bowel Disease (IBD), what happens to contractions due to inflammation?
Contractions are suppressed
78
What is a significant consequence of increased frequency of giant migrating complexes in IBD?
Can lead to significant erosions and hemorrhage
79
What is IBD's rank among inflammatory disorders?
2nd most common inflammatory disorder (after RA)
80
What are the two types of Inflammatory Bowel Disease?
* Ulcerative Colitis * Crohn's Disease
81
What is the incidence rate of IBD?
18:100,000 people
82
What characterizes Ulcerative Colitis?
Mucosal disease of part or all of the colon
83
What are common symptoms of Ulcerative Colitis?
* Diarrhea * Rectal bleeding * Crampy abdominal pain * N/V * Fever * Weight loss
84
What laboratory findings may indicate Ulcerative Colitis?
* ↑ platelets * ↑ erythrocyte sedimentation rate * ↓ hemoglobin and hematocrit * ↓ albumin
85
What warrants surgical colectomy in Ulcerative Colitis patients?
Hemorrhage requiring 6+ units of blood in 24-48 hours
86
What complication of Ulcerative Colitis is triggered by electrolyte disturbances?
Toxic megacolon
87
What is the mortality rate associated with colon perforation in Ulcerative Colitis?
15%
88
What is the most common site affected in Crohn's Disease?
Terminal ileum usually usually presenting w/ileocolitis and RLQ pain & diarrhea
89
What symptoms characterize Crohn's Disease?
* Weight loss * Fear of eating * Anorexia * Diarrhea
90
What happens to bowel function as Crohn's Disease progresses?
Diarrhea decreases and is replaced by chronic bowel obstruction
91
Crohns patients can be associated with________
arthritis, dermatitis, kidney stones
92
What is the mainstay treatment for IBD?
5-Acetylsalicylic acid (5-ASA) because it is antibacterial and anti-inflammatory
93
What are some medications used during flares of IBD?
* Glucocorticoids * Antibiotics (Rifaximin, Flagyl, Cipro) * Purine analogues
94
What is the recommended approach for surgical resection in IBD?
Resected segment should be as conservative as possible
95
What is the risk associated with >2/3 small intestine resection?
Short bowel syndrome, requiring TPN
96
Where do most carcinoid tumors originate?
GI tract but can occur in any area
97
What substances do carcinoid tumors secrete?
* Gastrin * Insulin * Somatostatin * Motilin * Neurotensin * Tachykinins * Glucagon * Serotonin
98
What is carcinoid syndrome?
Occurs in 10% of patients with carcinoid tumors where Lg amts of serotonin & vasoactive substances reach systemic circulation
99
What are the symptoms of carcinoid syndrome?
* Flushing * Diarrhea * Hypertension/Hypotension * Bronchoconstriction
100
Which side of the heart is more protected in carcinoid syndrome?
Left heart generally more protected as the lungs clear some of the vasoactive substances
101
Preop considerations for Carcinoid tumors
Octreotide before surgery and prior to tumor manipulation to attenuate volatile hemodynamic changes
102
What is the diagnostic method for carcinoid syndrome?
Urinary or plasma serotonin levels, CT/MRI
103
What is the main treatment for acute pancreatitis?
Aggressive intravenous fluids and NPO to rest the pancreas
104
What are common causes of acute pancreatitis?
* Gallstones * Alcohol abuse
105
What are the hallmark laboratory findings in acute pancreatitis?
* ↑ serum amylase * ↑ serum lipase
106
What imaging methods are used for diagnosing acute pancreatitis?
* Contrast CT * MRI * Endoscopic ultrasound (EUS)
107
Why has pancreatitis incidence increased?
alcoholism and better diagnostics
108
What is autodigestion prevented by and its relevance?
*Proteases packaged in precursor form
*Protease inhibitors
*Low intra-pancreatic calcium, which decreases trypsin activity
failure of any of these can trigger pancreatitis
109
Symptoms of pancreatitis
excruciating epigastric pain that radiates to back
N/V
abd distention
steatorrhea
ileus
fever
tachycardia
HoTN
110
What is ERCP?
Fluoroscopic examination of biliary & pancreatic ducts that interventions include stone removal, stent placement, sphincterotomy, hemostasis
111
What is the most common complication of acute pancreatitis?
Shock, ARDS, renal failure, necrotic pancreatic abscess
112
What is more common upper or lower GI bleeding?
Upper
113
What does orthostatic hypotension normally indicate?
HCT<30%
114
>25% blood loss will lead to _____________
HoTN & tachycardia
115
What indicates a bleed is above the cecum?
Melena
116
What procedure is the diagnostic/therapeutic choice for upper GI bleeding?
EGD
117
What is typically performed for persistent lower GI bleeding?
Angiography and embolic therapy
118
Lower GI Bleeding Characteristics
Generally, occurs in elderly
Causes include: diverticulosis, tumors, colitis
Unprepped sigmoidoscopy performed as soon as HD stable
Colonoscopy performed if pt can tolerate prep
Persistent bleeding warrants angiography and embolic therapy
119
What characterizes ileus?
Massive dilation of the colon without mechanical obstruction caused by loss of peristalsis
120
What are some causes of ileus?
* Electrolyte disorders * Immobility * Excessive narcotics * Anticholinergics
121
What medication can produce immediate results in ileus?
Neostigmine 2-2.5mg over 5 min
**cardiac monitoring required
122
What are the main functions of the GI tract?
* Motility * Digestion * Absorption * Excretion * Circulation
123
What are the layers of the GI tract wall from outermost to innermost?
* Serosa * Longitudinal muscle * Circular muscle * Submucosa * Mucosa
124
What is the role of the extrinsic nervous system in the GI tract?
SNS is inhibitory, PNS is excitatory
125
What alters GI function during anesthesia?
Anesthesia medications and their side effects
126
What is a significant risk associated with opioid use in GI surgery?
Reduced GI motility and constipation
127
What is the effect of volatile anesthetics on GI activity?
Depress electrical, contractile, and propulsive GI activity
128
What should be avoided when using nitrous oxide during abdominal surgeries?
Lengthy surgeries or when the bowel is already distended
- GI distention correlates with the pre-existing amount of gas in the bowel, as well as the duration and concentration of nitrous administered
129
What is the effect of neostigmine on bowel peristalsis?
Increases PNS activity and bowel peristalsis by increasing the frequency & intensity of contractions
130
What is the alternate reversal agent to neostigmine that does not affect motility?
Sugammadex
131
What can happen if ileus is left untreated?
Ischemia and perforation may occur
132
True or false: the higher anxiety = higher GI inhibition
True.
Inhibition of GI activity is directly proportional to the amount of norepinephrine secreted from SNS stimulation
133
Name the order of recovery of the GI tract after anesthesia
The small intestine is the first part of the GI tract to recover, followed by the stomach in approximately 24 hours and then the colon 30 to 40 hrs postop
134
True or false: NMB affect GI motility
False, they only affect skeletal muscle
135
How do opioids affect the system
Stimulate mu, delta, and kappa receptors, there are a lot of mu receptors in the myenteric and submucosal plexuses and activation causes delayed gastric emptying and slower GI transit
136
The primary movements within and along the GI tract
Mixing and propulsive
