INFECTIONS - Medicine for Mountaineering and Other Wilderness Activities - page 303

CHAPTER 22
INFECTIONS
C. Kirk Avent, M.D.
Principal Contributor
Infections occur whenever microorganisms invade body tissues and multiply within them.
Humans normally have harmless organisms, which rarely cause disease, in such sites as the
skin, throat, and intestines. However, when the body's defenses against infection are defi-
cient, whenorganismsthatarenotharmless arepresent,orwhenaninjuryallowsorganisms
to enter tissues in which they are not normally present, infection may result.
Infections that are transmitted directly or indirectly from one person to another, such as
influenza and streptococcal sore throat, are contagious. Others, such as urinary tract infec-
tions or appendicitis, although infectious, are not contagious. Many of the infections of con-
cern to wilderness enthusiasts are transmitted by vectors such as mosquitoes (malaria and
yellow fever) and ticks (Rocky Mountain spotted fever and Lyme disease). Few infections
likely to occur in the wilderness are so contagious that they require isolation precautions.
A boil or abscess in the skin typifies the pain, swelling, redness, and heat produced by
the inflammation accompanying localized infections. An infection confined to a small area
such as the superficial layers of skin usually does not cause fever or other systemic symp-
toms.Ifalocalizedinfectionextendsdeeply,however,organismsmayenterthebloodstream
and disseminate throughout the body. Individuals with such widespread infections normally
have chills, fever, and malaise. Additional nonspecific symptoms may be headache, nausea,
vomiting, and back pain.
When localized signs of disease accompany fever, identification of its cause is not dif-
ficult. For example, burning pain on urination, frequent passage of small amounts of urine,
anddiscomfortoverthebladderorkidneysindicateaurinaryinfectionisprobablythecause
of chills and fever. Similarly, if pleuritic chest pain is accompanied by a cough productive
ofthick yellow sputum, the diagnosis is pneumonia. The infections discussed in this chapter
are those that involve the skin and selected other generalized infections. Infections of spe-
cific organs are discussed in the chapters dealing with those organs or systems.
ANTIBIOTICS
Although a large number of antibiotics have been developed for the treatment of infectious
diseases, organisms vary greatly in their sensitivity to individual drugs. An antibiotic that
is effective against the specific causative organism must be used for each infection. For ex-