GI Pathology: Nausea, Vomiting, Diarrhea
Vomiting is technically defined as forceful eviction of the stomach contents caused by contractions of the GI tract and muscles of the thorax.
We will also include some disorders characterized by regurgitation, which is when food is ejected from the esophagus.
Medications:
Antibiotics
Opioids
Antidepressants
Vitamins and mineral supplements
NSAIDs
Chemotherapy
GI motility issues Prevent normal passage of food and result in nausea/vomiting; this can be due to damaged nerves or mechanical obstruction.
Esophageal achalasia is a rare condition in which the nerves in the
esophagus are damaged and the lower esophageal sphincter cannot relax.
As a result of sustained sphincter contraction, food cannot pass to the stomach and patients experience heartburn, chest pain, and regurgitation (backflow of food into the throat).
Gastroparesis can result from
vagus nerve damage and loss of stomach muscle function.
Food is not pushed through the stomach to the small intestine properly, so patients feel full after eating small amounts of food and may experience heart burn and vomiting or regurgitation.
Mechanical GI obstructions include adhesions, volvulus, foreign bodies, hernias, tumors, etc.
Motion sickness occurs when there is a mismatch between our expected and experienced sensory inputs our brains become confused about whether the body is stationary or moving.
Early pregnancy is associated with nausea and vomiting; though often referred to as "morning sickness," these symptoms can occur any time of the day and are the result of hormonal changes in during the first trimester.
Central nervous disorders associated with nausea and vomiting include:
Migraines, infections, increased intra-cranial pressure, such as brain tumors or injury
Cyclical vomiting syndrome is characterized by recurring severe episodes of vomiting that can be brought on by stress and excitement. This syndrome is rare, and often begins in childhood. It is thought to be the result of disordered brain-gut interactions, and is often associated with the development of migraines.
Complications of vomiting:
Aspiration (movement of vomit into the lungs), dehydration, electrolyte imbalance, undernutrition, and esophageal tears.
Lactose intolerance causes diarrhea with abdominal pain and camping; lactose is a sugar found in mammalian milk, and requires the enzyme lactase for breakdown in our GI systems. There are different causes of lactose intolerance, but the most common cause in adults is a primary lactase deficiency.
Celiac disease is characterized by an inflammatory autoimmune response in the small intestine in response to gluten, which is a found in wheat, rye, and barley.
Inflammatory bowel disease includes
Crohn's disease and ulcerative colitis which are characterized by mucous and bloody diarrhea, respectively.
Microscopic colitis is characterized by watery diarrhea.
Pancreatic insufficiency is characterized by a lack of digestive enzymes; as we might expect, this means that foods and liquids aren't absorbed.
As a result, patients have watery diarrhea (due to osmotic forces in the intestines) and
steatorrhea, which is due to the malabsorption of fats.
Steatorrhea (aka, fatty stools) is characterized by oily, foul smelling stool that is often yellowish and floats due its high fat content.
Neuroendocrine tumors produces
carcinoid syndrome in 30-40% of patients; it is associated with watery, loose stools, as well as flushing, wheezing, and valvular heart disease.
Complications of Diarrhea:
Malabsorption of nutrients, dehydration, and electrolyte imbalances.
Nausea, Vomiting, and Diarrhea - Combined
Gastroenteritis
Infections can be from a variety of pathogens that are consumed with tainted food or water.
Top causes:
norovirus,
rotavirus (esp. in children),
E. coli,
Salmonella,
Shigella, and
Campylobacter.
Intestinal ischemia
Occurs when the
mesenteric arteries become blocked. Can cause nausea, vomiting and bloody diarrhea.
Functional bowel disorders
Irritable bowel syndrome is the result of disordered brain-gut communication.
Endocrine disorders
Particularly
thyroid disorders,
adrenal insufficiency, and
diabetes.
