GASTROINTESTINAL DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 247

CHAPTER 19
GASTROINTESTINAL DISORDERS
Martin I. Radwin, M.D.
Principal Contributor
The gastrointestinal tract consists of the mouth and throat, esophagus, stomach, small and
large intestines, liver, gallbladder, and pancreas. This system ingests food, converts it into
forms that can be absorbed and used by the body, and excretes the residual waste.
The esophagus functions after swallowing by propelling food into the stomach by peri-
stalsis, where it is digested for thirty to ninety minutes by pepsin in the presence of hydro-
chloric acid. The resulting particulate food next passes into the first part of the small intest-
ine (duodenum) where enzymes from the intestinal mucosa and the pancreas further prepare
the partially digested food for absorption. Bile, which is produced by the liver and stored
in the gallbladder, helps emulsify fats so they can be absorbed. Absorption takes place pre-
dominantly in the middle and lower segments of the small intestine (jejunum and ileum). In
the large intestine, water is extracted from the residual material. All blood from the small
intestine first goes to the liver, where an array of complex biochemical reactions converts
the absorbed nutrients to substances needed by all tissues and organs.
Diseases of many organs produce signs and symptoms referable to the gastrointestinal
tract, particularly nausea and vomiting. Illnesses originating in the gastrointestinal tract pro-
duce similar symptoms and often cannot be distinguished without sophisticated diagnostic
facilities. Furthermore, even when the nature of a disorder is known, specific therapy may
not be available. Therefore, the treatment for most gastrointestinal disorders that appear for
the first time in a wilderness situation or in a remote area of a developing country is limited
to alleviating symptoms.
The signs and symptoms of disease of the gastrointestinal system are nausea and vomit-
ing,diarrhea,constipation,bleeding,jaundice,andpain.Painthatcomesonsuddenlyissuch
an eminent problem that it is discussed separately in Chapter 20: Acute Abdominal Pain , as
are procedures for examining the abdomen.
NAUSEA AND VOMITING
The causes of vomiting are innumerable and include such widely differing disorders as mo-
tionsickness,headinjuries,metabolicdisorders,infections,pregnancy,ulcers,environment-
al heat, altitude illness, and appendicitis.
If a person is stuporous or unconscious, a single bout of vomiting can be disastrous be-
cause the gastric contents can be aspirated into the respiratory tract. Lethal respiratory ob-
structioncanresultifthevolumeofaspiratedmaterialislarge.Ifasmalleramountofvomit-
us is aspirated into the lungs, the resulting severe pneumonia is difficult to treat. At the first