Nausea & Vomiting - Exam 3 Flashcards
define nausea. define vomiting
nausea: Subjective feeling of a need to vomit.
Vague, intensely disagreeable sensation of sickness or “queasiness”
vomitimg: Usually follows nausea, including retching (spasmodic respiratory and abdominal movements)
What is regurgitation? Rumination?
Regurgitation: The effortless reflux of liquid or food stomach contents
“Burping up” food contents
rumination: The chewing and swallowing of food that is regurgitated after meals
The motor function of the gut is controlled at three main levels, what are they?
parasympathetic and sympathetic nervous systems
enteric brain neurons
smooth muscle cells
What causes nausea?
caused by a gastric rhythmic disturbance in which the natural 3-cycle-per minute gastric myoelectrical activity (muscle contraction and relaxation) is altered
naturally increases with food intake but that is normal
define tachygastria. define bradygastria
Tachygastria: increased rate of electrical activity in the stomach, more than 4 cycles per minute
Bradygastria: decreased rate of electrical activity in the stomach, less than 2 cycles per minute
Vomiting may be stimulated by ___ different sources. List them
4 different sources
- Afferent vagal fibers from the GI viscera (rich in serotonin 5-HT3)-> GI distention, mucosal or peritoneal irritation, infections
- Fibers of the vestibular system (high concentrations of histamine H1) -> sea-sick, dizzy
- Higher CNS centers -> certain sights, smells or emotional experiences may induce vomiting
- Chemoreceptor trigger zone (rich in opioid, serotonin 5-HT3, neurokinin 1 (NK1), and dopamine D2 receptors) -> located outside of blood-brain barrier in the area postrema that can be stimulated by drugs, chemo agents, toxins, hypoxia, uremia, acidosis, radiation therapy and induce vomiting
What is area postrema?
a structure in the brainstem that detects toxins in the blood and cerebrospinal fluid (CSF) and triggers vomiting
a highly vascular paired structure in the medulla oblongata in the brainstem that can induce vomiting
What is superior mesenteric artery syndrome?
When the duodenum gets crushed by the superior mesenteric artery
**Draw the chart that correlates the likely microbe to the incubation period with the likely food source ** know entire chart. What is the big take away?
big take aways: bacteria have a much shorter incubation period than viruses
What are some life-threatening disorders that need to quickly rule out that can present with N/V?
bowel obstruction
mesenteric ischemia
acute pancreatitis
myocardial infarction
What is the 3 step approach to a pt with N/V?
- determine etiology
- The consequences or complications of nausea and vomiting should be identified and corrected ie: fluid depletion, hypokalemia, and metabolic alkalosis
- targeted therapy for underlying cause
What does acute N/V symptoms WITHOUT severe abd pain make you think could be the underlying cause? list 4
typically caused by food poisoning
infectious gastroenteritis
drugs
systemic illnesses
What does acute N/V symptoms WITH severe abd pain make you think could be the underlying cause?
suggests peritoneal inflammation
acute gastric/intestinal obstruction
pancreatobiliary disease
How does cannabinoid hyperemesis syndrome present? Who is the MC pt? What helps to improve symptoms?
What does vomiting of undigested food one
to several hours after meals make you think?
gastroparesis
gastric outlet obstruction: may hear a succussion splash
What does vomiting of undigested food one
to several hours after meals with a succussion splash make you think?
gastric outlet obstruction
vomiting with what 4 s/s would make you think a neurologic cause?
headache
stiff neck
vertigo
focal weakness/paresthesias
if you see feculent vomiting, what are you instantly thinking?
Feculent vomiting = Intestinal obstruction
When will hyperactive bowel sounds present in a bowel obstruction?
hyperactive bowel sounds happen EARLY in bowel obstruction
define hematemesis
Vomiting of blood or coffee-like material
aka upper GI bleed
What are you worried about the pt developing with persistent severe vomiting?
electrolyte disturbances
_______ is a good starting point for imaging with N/V. What are you looking for?
Flat and upright abd xray
severe bowel obstruction
In SBO, will show intestinal air-fluid levels with reduced colonic air
Ileus - will show diffusely dilated air-filled bowel loops
____ is ordered with most chronic N/V that is unexplained after routine eval. What is a common result? What can an EDG pick up?
EGD
often normal
Detects ulcers, malignancy, retained gastric food residue, gastric outlet obstruction
____ test will show inflammation in Crohn’s disease. Would want to order ______ if concerned about motor disorder when anatomic abnormalities are absent
MRI
GI motility testing
What is a Mallory-Weiss Tear?
a tear associated with chronic retching and vomiting. Typically the mucous membrane at the junction of the esophagus and the stomach develops lacerations
What is Boerhaave Syndrome?
esophageal rupture due to severe straining
If a pt is persistently vomiting need to always correct _______ and monitor for s/s of _______
ALWAYS ASSESS FOR S/SX HYPOVOLEMIA
ALWAYS OBTAIN ELECTROLYTES IF PROLONGED VOMITING
Once a pt starts to improve with fluids and nutrients are restarted, what do they need to avoid in the first few days? Why?
avoid high fat food
because lipids delay gastric emptying and prolong gastric retention
What is the tx for mil/moderate N/V?
Clear liquids (broths, tea, soup, carbonated beverages)
Advance to small quantities bland food (crackers)
Antiemetic medication
What is the tx for mod/severe N/V?
Hospitalization with IV (isotonic) fluids
Antiemetic medication
NG tube in certain situations (i.e. small bowel obstruction/gastric)
What is the goal of replacement fluid therapy for N/V?
The goal of replacement therapy is to correct existing abnormalities in volume status and/or serum electrolytes.
What does the rate of replacement therapy depend on in N/V?
replacement depends on the severity
What is the tx for severe volume depletion or hypovolemic shock?
At least 1 to 2 liters of isotonic fluids given as rapidly as possible in an attempt to restore tissue perfusion.
Continued at a rapid rate until the clinical signs of hypovolemia improve
What is the tx for mild/moderate hypovolemia?
Rapid fluid resuscitation is not necessary
Induce positive fluid balance = administration of fluid at a rate that is 50 to 100 mL/hour greater than estimated fluid losses.
How do you chose what replacement fluid to use?
depends on the type of fluid that has been lost and any concurrent electrolyte disorders
low/high Na: give sodium plus fluids SLOWLY
low K: give K
give bicarb if pt is in metabolic acidosis
What 5 pt populations do you need to be use caution when considering giving them a parenteral fluid bolus?
infants
patients with poor systolic ejection fraction
kidney disease
chronic severe hyponatremia (without neuro deficits that require hypertonic saline)
DKA in children
What drug class is meclizine?
Antihistaminergic
What drug class is scopolamine?
anticholinergic
What drug class is ondansetron? What is the MOA? What is important to note about it?
5-HT3 antagonist
Blocks serotonin from binding to 5-HT3 receptors
Blocking stimulation of “vomiting center” in medulla
acts on both peripheral and central
What drug class is aprepitant? When is it commonly used?
NK1 antagonist
chemo induced N/V
What drug class is metoclopramide? When is it used?
5-HT4 agonist and antidopaminergic
gastroparesis
What drug class is octreotide? When is it used?
Somatostatin analogue
intestinal pseudoobstruction
_____ needs to be avoided in the first trimester due to _____. Is it metabolized by the _______
Ondansetron (Zofran)
rare chance of cleft palate
liver, caution in hepatic impairment
What are the safety/monitoring requirements for ondansetron? What is the MC SE?
pregnancy (NO in first trimester)
QT prolongation
HA
**________ is the recommended by American College of OBGYN 1st line therapy N/V with pregnancy
doxylamine
______ is a first generation antihistamine. What unique form does this medication come in?
Promethazine (Phenergan)
rectal suppository if the pt cannot keep anything down
What are the 3 highlighted SERIOUS adverse reactions with promethazine?
respiratory depression
extrapyramidal SE
bradycardia
** What are the 2 BBW with Promethazine (Phenergan)?
Respiratory Depression
Tissue Injury/Necrosis -> if given IM only at the injection site
What is the CI for promethazine? Pt is on promethazine for a prolonged time frame, what 2 things do you need to monitor?
cannot give to kids under 2 years old due to RESPIRATORY DEPRESSION
obtain CBC and need ophtho exam
_____ MOA Increases peristalsis primarily by inhibiting dopamine. Enhances response to acetylcholine of tissue in upper GI. Enhances motility and accelerated gastric emptying.
Increases lower esophageal sphincter tone
What drug class?
Give 2 additional times this medication is used.
Metoclopramide (Reglan)
prokinetic
gastroparesis and refractory GERD
**What is the serious SE of metoclopramide?
Neuroleptic malignant syndrome
**______ is a life threatening reaction to ________ characterized by fever, autonomic dysfunction, altered mental status and muscle rigidity
Neuroleptic malignant syndrome
metoclopramide
**What is the BBW for metoclopramide? What are the CI?
tardive dyskinesia
CI: seizure dzs, GI obstruction
What are the 3 safety/monitoring need to knows with regards to metoclopramide?
_____ is the Neurokinin receptor antagonists. When is it used?
Aprepitant (Emend)
During chemotherapy with dexamethasone
**_______ and ______ are given to chemo pts to help with the chemo induced vomiting
lorazepam and zofran
Go back and look at the case studies and review questions from this lecture!
do it!!!
