(06) Smooth Muscle II Flashcards
What are the units of motility?
When we see animals that have gastrointestinal motility disorders, where can they be found?
- neurons, muscle, channels, proteins
- enteric neuron, synaptic space, or smooth muscle cell
What are the three types of GI motility disorders?
What is caused by inappropriate relaxation?
What are the two main things that go into esophagus during acid reflux from stomach?
If sphincter between duodenum and pylorus is also compromised, what can get into the esophagus?
What animals get this most commonly?
What can we do about it?
What’s a circumstance of impaired relaxation?
- delayed transit (primary one), impaired relaxation, inappopriate relaxation
- acid reflux, due to relaxation of gastroesophagel sphincter
- gastric acid and gastic pepsin
- bile salts, pancreatic enzymes, bicarbonate
- dogs and cats
- do things to interfere with acid effect, drugs that inhibit acid secretion, we could also give a prokinectic agent that could increase tone of sphincters and increase gastric emptying
- ingestion of foreign bodies, cancer - both act as obstructions - also pyloric stenosis (muscle hypertrophy) narrowing of the pylorus
What are four example of delayed transit (GI Motility Disorder)?
- Esophageal hypomotiliy, megaesophagus
- Delayed gastric emptying, gastroparesis
- Intstinal Ileus, pseduo-obstruction
- Colonic hypomotility, constipation, megacolon
What are these radiographs an example of?
What preceded this condition?
What did this allow?
What animal do you see this in?
Acute or chronic?
- megaesophagus
- esophageal hypomotility
- Allow food to sit and ferment, and thus dilate the esophagus
- dog
- usually chronic
(THE THREE FORMS OF Canine Idiopathic Megaesophagus and Esophageal Hypomotiliy)
- Congential (born with it) - _____
- Acquired secondary (associated with another disease) - 10 of these
- Acquired Primary - _____
- developmental neuropathy
- myasthenia gravis, esophagitis, Addison’s disease, lead poisoning, hiatal hernia, myositis, dermatomyositis, brainstem disorders, muscular dystrophy, hypothyroidism
- Acquired nueropathy (not a smooth muscle disorder) - lesion involving the innervation of the esophagus
(Overview of Therapy of megaesophagues)
_______ Feedings – _____ dependent flow
Food ______ – Food fed in the _____ phase
Nutritional Maintenance – High _____
_____ Feedings – For ______ patients
______ – Antibiotics (G+, G-)
______ – ______, 5-15 mg/dog PO TID
_______ – _____, 0.5-1.0 g/dog PO TID
- elevated, gravity
- density, aqueous
- digestibility
- Tube, refractory
- Pulmonary infections
- Motility, Bethanechol (smooth muscle agents don’t work on dogs because all striated - need to use choimilimetic agents - binds to nictonic-cholinergic receptor)
- Esophagitis, Sucralfate (treat inflammation of this - treats the chemical burn) (bind to necrotic tissue proteins - allows mucosa to heal spontaneously)
- When we have aspiration of gastro-intestinal food content from the GI tract into the airway what is the profile of the organisms that are aspirated into the airway?
What kind of antibiotic do we use?
- g+, g-, anaerbobes, aerobes
- broad-spectrum
- Stricture
- Dilation
- Tumor
- Chemotherapy, 2. Resection
- Foerign body
- endoscopy 2. surgery
- myasthenia
- pyridostigmine, prednisone
- esophagitis
- sucralfate; H2 antag; ATPase inhibitor
- neuropathy
- elevated feedings; liquid consistency; high digestibility
- Resolution
- no improvment
- G-tube feedings, Bethanechol; sucralfate
What is this?
What could cause this (gastric distension and delayed gastric empytying)? (6 things)
What can be done to counteract delayed gastric emptying?
- Gastric Distension
- volvulus (twist of an organ on an axis), but not necesarrily
1. Post-Gastric Dilatation/Volvulus (most important in canine)
● 2. Gastritis/Inflammatory Bowel Disease
● 3. Gastric Erosion/Ulcer
● 4. Dysautonomia
● 5. Electrolytes - ↓ K+, ↓ Ca2+
● 6. Metabolic Disorders – D.M., uremia,
Addison’s disease
- There are prokinetic drugs (agents) for this
What’s going on here? What specifcally?
What are the specific disorders of Intestinal Transit (the ileus)?
How can these be treated?
- disorder of the intestinal tract
- parvo
- Dysautonomia (rare), Post-operative ileus (common), Opiod dysfuction (common), Viral enteritis (common), Radiation enteritis (uncommon), and some others….
- Prokinetic agents (Mosapride, Metoclopramide, Loperamide) - notice that these are different than the prokinetc agents for stomach - differnent classes of prokinetic agents work better in different areas (stomach, intestines, colon)
What’s going on here?
What happens if constipation gets worse?
In feline megacolon, what is it a problem of?
- Colon motility disorder (constipation - difficult/delayed/painful defecation)
Obstipation = (constipation + losss of normal colonic motility patterns) - will then dilate and became megacolon
- not a problem of innervation (as it is in canine megaesophagus) - problem colonic smooth msucle
What are the four principles of therapy of Constipation/Obstipation/Megacolon?
What are the main classes of Drugs used to treat This?
_____
- metoclopramide, domperidone
_____
- mosapride, cisapride, prucalopride, tegaserod
_____
- erythromycin lactobionate, stearate, succinate
_____
- ranitidine, nizatidine, bethanechol
_____
- AMU-301
- Removal of Impacted Feces, Laxative Therapy, Colonic Prokinetic Agents, Sub-total Colectomy
- D2 Dopaminergic Antagonist Drugs
- 5-HT4 Serotonergic Agonist Drugs
- Motilin-like Drugs (Motilides)
Cholinomimetic Agents
Nitric Oxide (NO) Donors
