5 Steps in Sequence of Vomiting
- Reverse peristalsis in small intestine
- Relaxation of stomach and pylorus
- Forced inspiration to increase abdominal pressure
- Relaxation of LES and forceful expulsion of contents
- Relaxation of UES
What steps in vomiting constitute retching?
steps 1 through 4
Diarrhea
an increase in the frequency of defectation or fecal volume
4 Types/Causes of Diarrhea
- Osmotic Diarrhea
- Secretory Diarrhea
- Infectious Diarrhea
- Increased Motility
Most common type of diarrhea seen in practice?
osmotic diarrhea
Overall cause of osmotic diarrhea?
maldigestion and malabsorption
Osmotic Diarrhea
essentially a high concentration of undigested solutes remain in the GI tract therefore the gradient keeps water within the lumne rather than being absorbed
5 Possible Causes of Osmotic Diarrhea
- Digestive enzme deficiencies
- Bile salt malabsorption
- Ingestion of unabsorbable solute
- Decreased epithelial surface area
- Genetic mutation affecting SGLT-1 (sodium transporter)
Simplest way to stop osmotic diarrhea?
remove the causing agent (can also treat with osmotic laxatives)
2 Causes of Secretory Diarrhea
- Increased [chloride] secretion
- Reduction in electrolyte absorption
Relation bewteen chloride and secretion
more chloride in lumen = more secretions
Normal Mechanism of Chloride Secretion
simply put, increase in intracellular protein kinase activity phosphoylates and widens the opening of CFTR channels increasing Cl- secretion
Pathogens that can cause uncontrolled chloride secretion (3)
- E. coli
- Vibrio cholerae
- C. diff
Why do toxins cause uncontrolled chloride secretion?
There’s not a feedback loop, the body doesn’t respond to decrease the amount - toxins will keep producing toxins, Cl- is continuously released (and can also inhibit sodium absorption via its exchanger)
Premise of Rehydration Therapy for Secretory Diarrhea
toxins block your Na+/H+ and Bicarbonate/Cl- exchangers, but your sodium cotransporters still function –> give sugars or AAs to get sodium in the cell, and chloride absorption (passive) will follow
Congenital Chloride Diarrhea
genetic mutation of Bicarbonate/Cl- exchanger –> defective absorption of Cl-
Will secretory diarrhea stop if you withhold food?
NO, it will continue
2 Types of Infectious Diarrhea
- Inflammatory
- Noninflammatory
3 Types of Infectious Agents
- Bacteria
- Viruses
- Parasites
Most common cause of secretory diarrhea?
cholera toxin (technically infectious)
How do infectious agents cause diarrhea? (2)
- Modulate epithelial ion transport
- Disrupt epithelial barrier function
Non-Inflammatory Diarrhea Symptoms
negative fecal leukocytes, watery/large volume, no blood, no fever
Inflammatory Diarrhea Symptoms
positive fecal leukocytes, mucoid/small volume, bloody, fever
Type of Diarrhea caused by motility issues?
Irritable Bowel Syndrome (increases peristaltic contractions, increased motility, not enough time for segmentation to absorb)
