Gastroparesis Flashcards
What is gastroparesis?
SYMPTOMS consistent with delayed gastric emptying
WITHOUT mechanical obstruction
AND delay in 4 hr solid phase gastric
Gastroparesis is usually caused by:
50% idiopathic!! Mostly women
Neuropathy.
Injury to the ENS is common
Vagal injury is not the cause in all patients
What are the Sx of gastroparesis?
N/V Early satiety Epigastric pain Anorexia and weight loss GERD Bloating
What are some causes of gastroparesis?
Diabetes Surgery Ischemia Neurologic Inflamatory Meds Transplant Cirrhosis Paraneoplastic
Describe the five components of the pathophys of gastroparesis
- Fundal hypomotility
- Antral hypomotility
- Antropyloroduodenal spasm
- Gastric pacemaker dysrhythmias
- excessive inhibitory feedback w/ NO or VIP
What’s on your differential for gastroparesis?
Functional dyspepsia
Mechanical obstruction
rumination
Medication
What are the complications of gastroparesis?
- bezoar
- GERD
- Cholecystectomy
- Mallory-weiss tear
What is the best test for gastroparesis?
4 hour solid phase gastric emptying scan
How do we treat gastroparesis?
- Diet: Small, low fat/fiber meals with liquids
- Prokinetics (metoclopramid and erythromycin
- Antiemetics
- gastric stimulation
- Surgery
How does metoclopramide work?
Increases ACh release
Inhibits dopamine receptors everywhere
What are the side effects of metoclopramide?
Tardive dyskinesia
Also acute dystonic reaction, parkinsonism
How does erythromycin work?
Induces Phase III of the MMC
–>more antral contractions
What are some challenges in treating gastroparesis?
- Symptoms do not correlate with rate of gastric emptying
- Treat predominant synptom
- Avoid surgery
What are the diagnostic criteria for functional dyspepsia?
Rome III: 1+ of the following
- Bloating after meals
- Early satiety
- Epigastric pain (most common)
- Epigastric burning
ALSO, no evidence of structural disease and 3 months of Sx PLUS onset 6 mos before diagnosis
Weight loss is also common
What are common causes of functional dyspepsia?
- Genetics
- Post-infectious
- inflammatory state
- Meds
What studies might be helpful for functional dyspepsia?
Upper endoscopy
CBC, LFT< ESR
–If vomiting, consider gastric emptying scan
What is highest on your differential for functional dyspepsia?
Gastroparesis
Treating FD is difficult–there’s no one medication that works! What are available options?
- Dietary/lifestyle changes
- H pylori eradication
- Antisecretory therapy (lowers acid secretion)
- Prokinetics
- Tricyclic antidepressants (SNRIs not effective)
What is the most common functional gastrointestinal disorder?
The most common functional gastrointestinal disorder–10-12%. Abdominal PAIN + discomfort and a change in bowel function
What are the diagnostic criteria for IBS?
Rome III:
- Recurrent abdominal pain or discomfort WITH 2+ of the following:
- Improves with defecation
- change in stool frequency
- change in stool form
At least 3 months with Sx and 6 mos after onset. DEFINED by Sx with normal blood work, imaging, and endoscopy
What are the three types of IBS?
- constipation
- diarrhea
- alternating
Describe the pathophysiology of IBS
A bunch of genetic/environmental/other factors affect serotonin, CRF, and adenosine levels in brain and bowel causing a change in motility, and visceral hypersensitivity
What are the four main symptoms of IBS?
- Abdominal pain/discomfort
- Bloating
- Constipation
- Diarrhea
What are some red flags when evaluating a pt with suspected IBS that would lead you down another path?
- weight loss
- > 50 yrs
- Anemia
- High ESR or WBC or TSH
- Rectal bleeding
- Arthritis/rashes
What is the purpose of doing a colonoscopy in IBS?
Not that useful…except for identifying more patients with microscopic colitis in pts > 45 years
How do you treat IBS?
Treat the symptom:
1. Pain=Antidepressants
2. Bloating: Serotonin agonist, or dietary
3. Constipation: Fiber, Mom/PEG
4. Diarrhea: Loperamide, Serotonin agonist
All can be treated with serotonin agonists/antagonists.
What is the IBS diet?
Low carbs, fructose, gluten, Fermentable Oligo, Di, Mono, polysaccharides and Polyols(FODMAP)
- No fruits
- No wheat/rye
- No artificial sweeteners w/ sorbital
- No raffinose (lentils/cabbage, brussels, asparagus)
What CAN you eat on IBS?
lean protein
- gluten free
- rice/corn/oat
- Select fruit/veg
- snow peas, bok choy, mandarin oranges
What other therapies (microbiome related) that can be used in IBS?
Probiotics (bifidobacteria)
Antibiotics (Rifaximin
What is the only drug that has been approved to treat IBS-D?
Alosetron. It’s a serotonin (5hT-3) receptor antagonist
What anti-osmotic agent is useful for IBS?
PEG
What drug is approved for IBS-C?
Lubiprostone, a type 2 chloride channel activator
-Increases choloride in lumen, Na follows to balance charge, and H2O follows
What are the enteric nervous system neurons derived from? What does it receive input from?
Neural crest cells
–Input from CNS and ANS, but is SELF functioning!
What are the two components of the enteric plexus?
submucosal and myenteric plexi
Which two layers does the submucosal plexus lie between? Which sections of the GI tract does it populate?
The inner circular muscle layer and mucosa. Found only in the small and large bowel
Between which two layers does the myenteric plexus lie btw? Which sections of the tract does it populate?
Between muscular inner circular and outer longitudinal layers. Found along the whole GI tract.
What does the submucosal plexus innervate?
- Secretory cells
- Endocrine cells
- Blood vessels
What does the myenteric plexus innervate?
- SECRETOmotor innervation
What are the major excitatory neurotransmitters in the GI tract?
Ach, substance P, and tachykinins
What are the major inhibitory neurotransmitters in the GI tract?
Nitric oxide
VIP
What is the role of serotonin in the GI tract?
Found in interneurons for motor, sensory, and secretory fxn
What are IPANs?
Intrinsic primary afferent neurons. They are the primary neurons carrying sensory signals and are embedded in the mucosa.
In contrast, extrinsic afferent neurons have cell bodies in DRGs
What do interneurons do?
Helps with crosstalk btw sensory and motor neurons (myenteric plexus) to cause peristalsis.
The main fxn of the vagus nerve in the GI is:
SENSORY afferent!
Describe the physiology of peristalsis
IPAN–>Myenteric plexus–>interneuron in myenteric plexus–>efferent motor neuron in myenteric plexus
What are the pacemaker cells of the gut?
Interstitial cells of cajal. “Pace” of the stomach is slower than the small intestine
What is the main fxn of the fundus?
Accommodating the food. High tone and low peristalsis
What is the main fxn of the antrum?
Grinding food. Low tone and high peristaltic activity
What nerve helps expand the fundus and initiate the grinding action of the antrum?
The vagus
What will a normal/abnormal EGG look like (Electrogastrography)?
Normal: coordinated movement
Abnormal: Not coordinated
What is gastric motility in the fed state?
Persistent, irregular contractile activity
What is gastric motility in the fasting state?
MMC:
Phase I: quiescence
Phase II: irregular phasic activity (antrum)
Phase III: short period of intense contraction (smal bowel)
What is the pathogenesis of nausea/vomiting?
Vagal/sympathetic afferents from all over–>stimulate vomiting center in medulla
OR: Chemoreceptor in area postrema of 4th ventrical outside BBB–>vomiting center
OR: afferents from CNS–>stimulate vomiting center
What is the most common acute cause of nausea and vomiting?
INFECTIONs
What are common causes of chronic N/V?
gastroparesis
Intestinal pseudo-obstruction
Psychogenic vomiting
What is the one symptom REQUIRED for gastroparesis?
Vomiting
What is the “braking mechanism” for the small bowel?
ileocecal valve
What stimulates the GI externally?
Parasympathetic innervation
What inhibits the GI internally?
Sympathetics
Which syndromes cause disorders in small bowel dysmotility?
- Scleroderma
- Hollow Visceral myopathy
- Intestinal pseudo-obstruction
- Irritable bowel syndrome
What happens in scleroderma?
Aperistalsis from loss of GI smooth muscle
- ->Esophagus most common, then small intestine/anorectal.
- ->gastric motility is preserved, with its 3 layers of muscle
What is the fxn of the colon?
Absorption
Formation of residue (poo poo)
storage
Transport
What are the three types of normal colonic motor patterns?
- Segmenting contractions (for mixing)
2. Propagating contractions (Low amplitude for short distance, high amplitude for long distances post meal)
What is Hirschsprung’s disease?
Failure of neural crest cells to move to the colon. Aganglionosis.
Sx: failure to thrive, distention, bloating, constipation. Pt won’t poop, with colonic dilation above affected segment
How do you diagnose hirschsprung’s?
anorectal manometry or biopsy
How do you tx hirschsprung’s?
surgery
What is anorectal manometry?
Put a balloon in rectum. Normally will cause RAIR (recto-anal inhibitory reflex) causing relaxation of the internal sphincter. The external sphincter is consciously controlled
What is colonic inertia?
Happens in young women, with infrequent stools (every 1-4 weeks)
Caused by loss if ICC cells
