Nausea and vomiting
1. Which of the following characteristic(s) is (are) consistent with nausea and
vomiting?
(A) Nausea is the subjective sensation of an impending urge to vomit, usually
perceived in the throat or epigastrium.
(B) Vomiting is the forceful ejection of contents of the upper gut from the mouth.
(C) Vomiting may occur in the absence of nausea in some settings.
(D) Regurgitation is different from vomiting in that the former refers to the effortless
return of gastric or esophageal contents into the mouth in the absence of coordination
of nausea and vomiting.
KEY: (A)+(B)+(C)+(D)
2. Which of the following does not belong to reflexible vomiting?
(A) chronic gastroenteritis
(B) acute appendicitis
(C) diabetic ketoacidosis
(D) chronic cholecystitis
KEY: (C)
3. Which of the following belong(s) to central vomiting?
(A) cephalitis and meningitis
(B) hypoglycemia
(C) hepatic encephalopathy
(D) glaucoma
KEY: (A)+(B)+(C)
Gastric retention
Obstruction under duodenal papilla
Duodenal ulcer or gastrinoma
Cardiac stenosis
(A) Vomitus without acid fluid
(B) Feculent vomitus
(C) Barmy or septic smell
(D) Vomitus with bile
(E) Vomitus with plenty of acid fluid
KEY: 4.C 5.D 6.E 7.A
4.
5.
6.
7.
8. If vomiting occurs at night, it should be considered as probably due to ( ).
A. pyloric obstruction B. chronic alcoholism C. functional dyspepsia D.
uremia
KEY: (A)
9. Please illustrate the pathogenesis of nnausea and vomiting.
Vomiting is a complicated reflex including three stages: nausea, vomiturition and
vomiting. In the stage of nausea, tensility and peristalsis of stomach decrease, while
tensility of duodenum increases with or without reflux of duodenal fluid. In the stage
of vomiturition, upper part of stomach relax with transient contraction of gastric
antrum. In the stage of vomiting, the abdominal muscles tighten against a relaxed
stomach with an open sphincter. The contents of the stomach are propelled up and out.
Vomiting is different from countercurrent regurgitation, in which the contents of the
stomach reflow up through the esophagus and out of the mouth without nausea and
contraction of diaphragm. The center of vomiting is located in the medulla consist
of two parts with different function. One is neural reflex center----vomiting center,
which located in the lateral medullary reticular formation in the medulla. The other is
chemoreceptor trigger zone at the base of the fourth ventricle of the brain. Vomiting
center receives afferent impulsion from digestive tract, pallium, inner ear vestibule,
coronary artery and chemoreceptor trigger zone, and administrates the vomiting
action directly. The chemoreceptor trigger zone has numerous dopamine D2 receptors,
serotonin 5-HT3 receptors, opioid receptors, Acetylcholine receptors, and receptors
for substance P. Stimulation of different receptors is involved in different pathways
leading to vomiting.