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Neoplasms 37
the routine examination. Also, the Pap test (a test to
screen for cervical cancer) should be performed at
regular intervals.
■ The ACS no longer recommends monthly testicu
lar self-exams for men because they have not been
shown to affect early diagnosis. However, the ACS
does recommend that men report to their health care
provider changes in how the testicle feels or looks
(ACS, 2018).
■ A rectal examination should be part of every medi
cal checkup for men and women, and stool samples
should be examined for blood, which might be an
indication of colon cancer.
Frequency of Cancer
Cancer is a focus of major concern for our society
because it strikes more than a million individuals per
year. Cancer, along with heart disease, causes more
than half of all deaths in the United States. Cancer is
responsible for approximately 600,000 deaths each
year. Approximately one out of three men and women
will be diagnosed with cancer at some point in their
lives. Cancer incidence is higher in men than in women.
Among racial/ethnic groups, there are more new cases
among African American men and white women.
Asian/Pacific Islanders of both sexes experience fewer
new cases. Cancer affects many lives, causing extreme
grief, suffering, and financial loss.
The term cancer covers a large number of specific
types of malignant neoplasms. Each of these types
might vary considerably from each other in behavior
and treatment, and the prognosis for these individual
types will depend on the individual cancer’s metastatic
rate, the extent of spread when discovered, and the
effectiveness of current treatments.
In general, the survival rate of cancer is approxi
mately 68%. Even though all malignant neoplasms
might fit into a classification of carcinomas, sarcomas,
leukemias, or lymphomas, there is a great difference in
the way they behave. Some types, such as pancreatic
carcinoma, are usually deadly, whereas skin carcinoma
seldom is.
Cancer affects people of all ages and both males
and females. The most common type of cancer is basal
and squamous cell skin cancer. These neoplasms are
seldom fatal because they are very visible, are slow
growing, and can be completely excised. Because
these tumors are generally treated in a physician’s
office, they are difficult to track statistically and are
usually excluded in statistical data. Malignant mela
noma, however, is a deadly form of skin cancer that
comprises approximately only 1% of all skin malig
nancies but is statistically recorded as skin cancer.
The most common types of cancer, excluding skin
cancers, are cancers of the lung, colon/rectum, breast,
and prostate. The lifetime probability of being diag
nosed with cancer and the lifetime risk of dying from
cancer are presented in Tables 3-5 and 3-6.
TABLE 3-5 Lifetime Risk of Being Diagnosed with Cancer—
Both Sexes, All Races
Site/Type Risk by Percent
All sites 39.65
Brain 0.61
Breast 6.37
Colon/Rectum 4.51
Kidney 1.60
Leukemia 1.47
Liver 0.91
Lung 6.57
Oral Cavity 1.10
Pancreas 1.52
Urinary Bladder 2.41
Modified from National Cancer Institute. (2014). SEER cancer statistics review
(1975-2-12). Devcan Version 6.8.0, August 2014. http://surveillance.caner.gov
/devcan. (accessed July 2016).
TABLE 3-6 Lifetime Risk of Dying from Cancer—Both
Sexes, All Races
Site/Type Risk by Percent
All sites 20.68
Brain 0.46
Breast 1.42
Colon/Rectum 1.90
Kidney 0.47
Leukemia 0.86
Liver 0.71
Lung 5.56
Oral Cavity 0.29
Pancreas 1.35
Urinary Bladder 0.61
Modified from National Cancer Institute. (2014). SEER cancer statistics review
(1975-2-12). Devcan Version 6.8.0, August 2014. http://surveillance.caner.gov
/devcan. (accessed July 2016).
38 Chapter 3
Diagnosis of Cancer
The prognosis for the individual with a malignant neo
plasm is best if the cancer is located and treated early.
Routine screening can be very effective in discovery and
early diagnosis of cancer. Screening measures include
regular Pap tests and mammograms for females. Screen
ing for males no longer includes a routine testicular
self-examination, but any change in how the testicle feels
or looks should be noticed and reported to the individ
ual’s physician. Occult stool examinations after age 40
to screen for colon cancer are important for both sexes.
The discovery of tumors can occur through routine
screening or accidentally during other diagnostic pro
cedures. For instance, X-ray examinations of the chest
prior to surgery might reveal a mass, or annual physical
examinations can lead to the discovery.
The recognition of cancer warning signs by an indi
vidual is important. The ACS lists several of these signs,
with the initial letters forming the acronym CAUTION.
They might be indicative of cancer development, so the
individual with one or more of these signs should be
evaluated immediately by a physician:
■ Change in bowel or bladder habits
■ A sore that does not heal
■ Unusual bleeding or discharge
■ Thickening or lump in breast or testicles or elsewhere
■ Indigestion or difficulty swallowing
■ Obvious change in a wart, mole, or mouth sore
■ Nagging cough or hoarseness
When discovered, more detailed radiologic exams,
such as computerized tomography, MRI, and positron
emission tomography scans, can be used to gain more
information on the size and location of tumor(s). (More
detailed information on these exams can be found in
Chapter 6, “Musculoskeletal System Diseases and
Disorders,” and Chapter 8, “Cardiovascular System
Diseases and Disorders.”)
Diagnosis of a tumor is made by microscopic exam
ination of the cells and tissue. Examination of cells is
called cytology (sigh-TOL-oh-jee; cyto = cell, ology
=study) or a cytologic examination. Live tissue
examina-tion is a biopsy, which is the most definitive
(clear-cutor without question) test used to diagnose a
tumor.
A Papanicolaou, or Pap test, named after its devel
oper, Dr. George Papanicolaou, can be used to examine
the cells. Although most people think of a Pap test as
a test only for cervical cytology, in reality, this simple
staining test can be used to examine other body fluids
such as urine, feces, sputum, prostatic fluid, or vaginal
fluids. After the sample is stained, it is placed under a
microscope and examined for abnormal cells.
To microscopically examine live tissue, a biopsy
must be done. A biopsy can be obtained by aspiration,
needle biopsy, endoscopy, or surgery. Aspiration biopsy
uses a needle attached to a suction device to remove a
small piece of tissue from the tumor. Needle biopsy is
obtained by punching a needle through the tumor and
using the tissue caught in the lumen of the needle for
examination. If the size of the needle is quite small, the
biopsy is called a fine needle biopsy. During endoscopy,
the tissue is removed by use of the appropriate scope,
for example, bronchoscope, colonoscope, or gastro-
scope. For a surgical biopsy, the tissue is removed by
cutting or incising the tissue (Figure 3-8).
A surgical biopsy can be performed with the patient’s
consent to excise the tumor if it is found to be cancerous.
After the biopsy is obtained, it is sent immediately to
the pathologist for diagnosis. The patient often remains
in the surgical suite under anesthesia while the surgeon
awaits these results. A technique called a frozen section
enables the pathologist to make a rapid determination
of the tumor condition: benign or malignant.
Signs and Symptoms of Cancer
Signs and symptoms of cancer are highly variable
according to the site and type of malignancy. Pain,
obstruction, hemorrhage, anemia, fracture, infection,
and cachexia might be manifestations of cancer. Any
one of these or a combination can be present, but often,
cancer is asymptomatic until late in its developmental
stage, including metastasis.
Pain
Pain from cancer is usually not an early symptom.
Cancer causes pain by growing to the point of causing
destruction of normal tissue, obstructing the lumen of
hollow organs like the intestine, placing pressure on
nerve endings, causing inflammation leading to dis
comfort, or any of these.
Obstruction
Obstruction of a hollow organ can occur from a tumor
growing inside the organ or from tumor growth out
side the organ that compresses or pushes into the organ.
Examples of obstruction could include the bronchus of
the lung and any area of the intestine.
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Neoplasms 39
Figure 3-8 (A) Tissue biopsy. A
small piece of tissue is surgically removed. (B) Pathologist views tissue under
microscope looking for presence of disease.
Hemorrhage
Hemorrhage can be caused by the cancerous tissue ulcer
ating and bleeding. This might lead to acute or chronic
blood loss and often results in anemia. Hidden blood in
the feces can be detected by an occult blood stool test.
Anemia
Anemia is very common in individuals with malignant
neoplasm and might be the result of tumor hemorrhage
or a decrease in red blood cell production as a result of
cancer treatments.
Fractures
Pathologic fractures might occur if a tumor has invaded
the bone and caused weakness at that site. A fracture
occurring from a minimal injury might be indicative
of a cancer but, in an older person, might also be due
to osteoporosis. The bone tumor might be primary or
secondary with cancer of the lung, breast, or prostate
readily metastasizing to the bone.
Infection
Infection is common and can lead to the demise of
the individual. Tumor ulceration can allow entry
of microorganisms that cause infection, or the
individual might have impaired immunity due to
chemotherapy (chemo = chemical, therapy = treat
ment) and radiation treatments, affecting the bone
marrow and causing a decrease in the production of
white blood cells.
Individuals with cancer often have a loss of appe
tite, leading to a poor nutritional state and an increase
in the chance of infection. Immune deficiency often
leads to infection of the individual by a host of organ
isms such as fungi, viruses, protozoa, and bacteria that
are not usually pathogenic.
Cachexia
Cachexia is a condition of general ill health and mal
nutrition often seen in the terminally ill patient (see
Figure 2-3 on page 17). This condition is evidence of
the demands on the body by the rapidly growing tumor
and treatment modalities, coupled with poor nutritional
intake.
Cancer Treatment
New technological advances lead to ever-changing
treatment of malignant neoplasms. Treatment might
be aimed at cure (curative), at relief of symptoms
(palliative; PAL-ee-AY-tiv), or at prevention (pre
ventive). Major types of treatment include surgery,
chemotherapy, and radiation, and hormone treatment
40 Chapter 3
might be the treatment of choice in some instances. The
oncologist might recommend one of these treatments
or a combination of them, depending on the type of
cancer and treatment plan.
Consider This...
1
A recent study revealed that cancer
patients who keep their sense of humor are
70% more likely to survive than those with
little or no sense of humor.
Surgery
Surgery for cancer can be curative, palliative, or
preventive.
Curative surgery is aimed at the complete removal
of the tumor. Cancer of the lung, stomach, skin, breast,
intestine, and female reproductive organs responds well
to this type of surgery.
Palliative surgery is usually indicated when a cure
is not possible but the surgery will alleviate pain and
discomfort. The intestine is an area that commonly
undergoes this type of surgery for obstruction, bleed
ing, or perforation. Surgery also might be performed
to sever nerves in an effort to reduce pain.
Preventive surgery might be performed to prevent
the development of cancer. Polyps in the colon can be
removed if they are thought to be precancerous, and a
woman might choose to undergo prophylactic mastec
tomy if she has been identified as being at high risk for
breast cancer.
Chemotherapy
Chemotherapy can be the medication of choice or used
in combination with surgery and radiation therapy.
Generally, chemotherapy is effective in treating rapidly
growing metastatic neoplasms. It is aimed at rapidly
growing neoplastic cells with the idea that it will kill or
inhibit the growth of these cells while having a minimal
effect on normal cells.
In some instances, the growth rate of normal cells
and neoplastic cells is not varied enough, and normal
body cells suffer from the effects of the treatment. Rap
idly growing normal cells such as those found in the
epithelium, hair, and bone marrow suffer the most,
leading to nausea, vomiting, loss of appetite, hair loss,
anemia, and impaired immunity.
Radiation
Radiation is generally used in treating a residual neo
plasm postoperatively and tumors that are not surgically
accessible or operable. Palliative radiation treatments
can shrink the tumor and relieve discomfort. Radiation
treatment can be external with direct radiation or inter
nal using radioisotope beads, seeds, or ribbons that are
implanted inside the body. Both methods are aimed at
disrupting DNA and interfering with cell growth and
replication.
Complementary and Alternative Therapy
Kambucha ambucha natural tea contains some elements that have been shown to have anti
cancer benefits as well as being an antioxidant. It is also used as an antifungal agent.
evelagelolOollle It contains vitamins, proteins, fiber, and other nutrients that have made it an appealing
Forms of Cancer beverage. Users tout many other advantages to Kambucha tea, but it can also be harmful
if it is not prepared correctly. Some nutritional agencies do not recommend the product
because of this. Standardized controls for the production of the tea need to be set to pre
vent harm to its users.
Source: Mousavi et al. (2020)
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Neoplasms 41
The goal is to destroy as much of the tumor as pos
sible without affecting the normal tissue surrounding
it. Adverse effects generally occur in the skin, mucous
membranes, and bone marrow, leading to nausea,
vomiting, loss of appetite, hair loss, and impaired
immunity.
Hormone Therapy
Hormone therapy can cause regression in tumors of
the breast and prostate. Administration of antago
nistic hormones or excision of hormone-producing
organs, such as the ovaries and the testes, can be effec
tive in prolonging life. Hormone therapy is generally
used as a palliative treatment for metastatic tumors.
Summary
N
eoplasms are new growths, either benign or malignant, that can arise from cells almost anywhere in the body.
Tumor is the term commonly used to describe a neoplasm, but not all neoplasms form tumors. Hyperplasias are
similar to neoplasms because they are an overgrowth of cells, but they resemble their cell of origin, whereas neoplasms
do not. Malignant neoplasms are usually called cancers and are usually named for the type of tissue from which they
developed. Metastatic cancers are those that spread to other parts of the body.
The cause of most cancer is unknown, but research has identified high-risk behaviors, as well as some carcin
ogens in the environment, that might contribute to cancer development. The ACS has recommended preventive
measures and lists seven warning signs of cancer. Although the mortality rate for cancer, in general, is still very
high in the United States, early diagnosis and treatment can yield a good prognosis for many types of cancer.
Review Questions
Short Answer
1. What is the difference between a neoplasm and a tumor?
2. How are neoplasms classified?
3. What is the largest group of malignant neoplasms?
4. When a malignant neoplasm moves to various parts or organs of the body, it is said to be a ___________ tumor.
5. What is the difference between hyperplasias and neoplasms?
True or False
6. T F Grading is the microscopic examination of the tumor to determine the degree of differentiation.
7. T F Tumors that are undifferentiated or anaplastic do not resemble the tissue of origin, are highly
malignant, and have a poor prognosis.
42 Chapter 3
8. T F Radioactive materials that emit alpha, beta, and gamma rays are not considered to be potential
carcinogens.
9. T F There is no known genetic predisposition for cancer.
10. T F There are several personal risk behaviors common in our society that put an individual at increased
risk for developing cancer.
Matching
6. Match the term in the left column with the phrase that best describes it from the column on the right.
Metastatic neoplasm
Cancer of the lung, breast, prostate,
and colon
CAUTION
Basal and squamous skin cancer
Biopsy
Liver, lungs, and brain
Ultraviolet (UV) radiation, X-ray,
and radioactive materials
Routine screening
Surgery, chemotherapy, and radiation
Palliative
a. Known carcinogens
b. An acronym for the seven warning signs of
cancer
c. Microscopic examination of live tissue
d. Responsible for the majority of cancer deaths
e. Cells whose growth pattern has no purpose and
is uncontrollable
f. Common sites of bloodstream metastasis
g. The most common type of cancer
h. Major types of cancer treatment
i. Treatment aimed at relieving symptoms
j. Very effective in the discovery and early diagnosis
of cancer
Case Studies
■ Mr. Holloway, age 65, has made an appointment for a routine checkup. He has not complained of any
unusual symptoms but feels he should have a yearly examination because of his age. What are some routine
screening tests that should be performed on Mr. Holloway because of his age and gender? What important
cancer prevention strategies should you discuss with Mr. Holloway during his visit?
■ Mrs. Holloway, age 55, is also visiting her physician for routine screening. She is concerned because her
sister, who is age 47, was recently diagnosed with breast cancer. What types of cancer are most commonly
diagnosed in patients like Mrs. Holloway, based on her age and gender? Should she be concerned about devel
oping breast cancer? What would you tell her about the physician’s exam and the mammogram?
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4
Inflammation
and Infection
Key Terms
Abscess (p. 48)
Adhesion (p. 52)
Antibodies (p. 44)
Antigen (p. 44)
Bacteria (p. 44)
Cellulitis (p. 49)
Chemotaxis (p. 45)
Culture and sensitivity
(p. 57)
Debridement (p. 51)
Dehiscence (p. 51)
Diapedesis (p. 45)
Empyema (p. 48)
Exudate (p. 45)
Fistula (p. 48)
Fungi (p. 53)
Helminths (p. 53)
Histamine (p. 45)
Hyperemia (p. 45)
Induration (p. 58)
Infection (p. 52)
Inflammation (p. 46)
Keloid (p. 52)
Lesion (p. 47)
Leukocytosis (p. 57)
Macrophage (p. 45)
Malaise (p. 57)
Mast cells (p. 45)
Opportunistic (p. 52)
Polymorphonuclear
cells (PMNs) (p. 45)
Primary union (p. 50)
Protozoa (p. 53)
Purulent (p. 48)
Pus (p. 45)
Pyogenic (p. 48)
Rickettsiae (p. 53)
Scar (p. 49)
Secondary union (p. 50)
Septicemia (p. 57)
Sinus (p. 48)
Tachycardia (p. 57)
Trauma (p. 45)
Ulcer (p. 48)
Virulent (p. 51)
Virus(es) (p. 53)
Learning Objectives
Upon completion of the chapter, the learner should be able to:
1. Identify important terminology related to the
defense mechanisms.
2. Describe the basic defense mechanisms in
the body.
3. Explain the steps in the inflammatory process.
4. Describe the process of tissue repair and healing.
5. Identify complications of wound healing.
6. Describe the process of infection development.
7. Identify the common infectious microorganisms
and the resulting diseases.
8. Identify the common laboratory test conducted to
identify pathogenic organisms.
Overview
T
he human body is in a constant state of activity, part of which is to prevent trauma and maintain homeo
stasis against foreign invaders and pathogens. It maintains defense mechanisms—inflammation is a
natural one—for this protection, but when these protective mechanisms fail, the usual result is an infection.
Infections are diagnosed and treated in a variety of ways. ■
43
Defense Mechanisms
The immune system has the difficult job of protecting
the body against foreign invasion. Defense can be non
specific, protecting the body against any and all invad
ers, or it can be specific, identifying the invader prior to
killing it. This system uses three basic lines of defense to
accomplish its protective goals.
Physical or Surface Barriers
(Nonspecific)
An intact skin is the body’s first line of defense. The
skin is a physical barrier and an acidic, antimicrobial
surface that is an effective barrier against infection most
of the time. The skin has more than 650,000 microor
ganisms per square inch on its surface, adding up to
more than 100 trillion microorganisms per person. The
normal bacterial flora of the skin acts as a placeholder,
preventing habitation by other bacteria (microscopic,
one-celled organisms). Sebaceous (oil secreting) and
odoriferous (perspiration-secreting) glands secrete
antibacterial acids and enzymes. Mucous membranes
serve to trap invaders.
Inflammation (Nonspecific)
If physical barriers are broken and the foreign invader
penetrates the cells and tissues, it triggers the sec
ond line of defense, the inflammatory response. This
response begins a stereotypic vascular response within
seconds of an unwanted invasion. In other words, the
process unfolds or follows the same pattern regardless
of the type of invader. The primary goals of the inflam
matory response are to isolate the invader, destroy it,
and clean up the debris, thereby promoting healing.
Immune Response (Specific)
The last line of defense reacts to invasion much slower
than inflammation but with specific killing ability. All cells,
even human body cells, have protein or saccharide mark
ers called antigens (AN-tih-jenz) on their surfaces that
identify the cell. During the immune response, the body
actually identifies the invader by the antigen. Once the
antigen is identified, lymphocytes produce antibodies.
These antibodies link with the cell antigen, thus kill
ing the cell or disabling it. This immunologic defense
has the unique ability to remember the invader and pro
duce more antibodies if the invader returns (Figure 4-1).
TYPES OF IMMUNITY
---- rr------
Specific
Identifies enemy
Mucous membranes
Immune response
T lymphocytes
(Identifies and kills with a toxin)
B lymphocytes
(Identifies and kills with an antibody)
Figure 4-1 Immunity—lines of defense.
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Inflammation and Infection 45
Inflammation
Inflammation is a nonspecific cellular and vascular
reaction to any tissue trauma (TRAW-mah; injury).
One limiting factor of inflammation, however, is that
it cannot occur in tissue that does not have a blood
supply.
If tissue is destroyed by injury, the inflammatory
process will occur only along borders of the injury
where blood supply is maintained. In gangrenous tis
sue, for example, inflammation cannot occur in the
dead or necrotic tissue, but there is an observable reac
tion along its borders.
The fact that inflammation occurs only in vascu
larized (supplied with blood) tissue is important in
forensic medicine. Evidence of inflammation in tissue
confirms that an injury occurred while the individual
was alive. If no evidence of inflammation exists, the
pathologist can be assured that the person was dead
when the injury was inflicted.
Inflammation is designed to be a beneficial, protec
tive defense mechanism. In some instances, the reac
tion can become so intense that it becomes harmful to
tissues. Such an acute hypersensitive reaction can lead
not only to local tissue damage but also to anaphylactic
shock and death of the individual. If the process goes
awry, producing an autoimmune reaction, the body
basically begins to destroy itself, and anti-inflammatory
medications might be needed to stop the reaction if it
becomes injurious.
The Inflammatory Process
When any tissue undergoes trauma, regardless of the
cause—physical injury, invasion of microorganisms,
ischemia (decreased oxygen in cells), freezing, burn
ing, electrocution, radiation, or chemical irritation, for
instance—inflammation will occur.
Mast cells, also called tissue histiocytes, exist in all
tissues of the body and play a major role in the inflam
matory process. When injured or irritated, these cells
release histamine. Histamine causes local arterioles,
venules, and capillaries to dilate, resulting in an increase
in blood flow to the area. This increase in blood flow,
called hyperemia (HIGH-per-EE-me-ah; hyper 5
increased, emia 5 blood), causes increased redness and
heat in the area.
Hyperemia also brings increased numbers of leu
kocytes (white blood cells) to the area. The white cells
that move into this area first and in the greatest numbers
are neutrophils, also called polymorphonuclear cells
(PMNs; poly 5 many, morphic 5 shaped nucleus).
These white cells line the endothelium of the vessels,
awaiting the opportunity to move into the tissue.
As the capillaries dilate under the influence of his
tamine, vascular permeability occurs. In other words,
the capillary becomes permeable, or leaky, as the endo
thelial cells are stretched apart. This permeability allows
blood fluid called exudate (ECKS-you-dayt) to leak into
the tissue. This leakage of fluid is the cause of the swell
ing or edema observed with inflammation.
As edema increases, more pressure is exerted on
nerve endings, leading to increased pain. With increased
pain and tenderness, the individual tends to guard the
area and may experience loss of function. These vascular
and cellular responses produce the five cardinal signs of
inflammation: heat, redness, swelling, pain, and loss of
function (Figure 4-2).
Vascular permeability also allows the waiting
neutrophils to escape into the tissue. The neutro
phils extend part of their bodies between the epithe
lial cells and squeeze through the capillary wall by a
process called diapedesis (DYE-ah-pe-DEE-sis; see
Figure 4-2). The process of diapedesis is very effec
tive, delivering millions of neutrophils to the area
within a few hours.
Neutrophils can be considered the foot soldiers of
the inflammatory process. They arrive first, they arrive
in great numbers, and they readily move into action in
the tissue, drawn or directed to the injured area by a
process called chemotaxis. One might think of this pro
cess as a chemical taxicab. Chemicals, detected through
chemoreceptors on the neutrophil’s outer membrane,
are released by a variety of elements such as bacteria,
injured tissue, and plasma proteins. These chemore
ceptors also draw the neutrophil in the direction of the
highest chemical concentration (see Figure 4-2).
When the neutrophil arrives at the scene of the
trauma, it begins the job of phagocytosis, or cell eating.
The neutrophil eats and destroys microorganisms, for
eign materials, and dead cells. However, the life of the
neutrophil is short. The death of numerous neutrophils
mixed with exudate or blood fluid make up, in part, the
white fluid identified as pus.
Approximately 3 to 4 days after the inflammatory
process begins, large numbers of another type of white
cell, the large, slow-moving monocyte, begin to arrive at
the scene. As the monocyte leaves the bloodstream and
moves into the tissue, it, too, becomes phagocytic and
is called a macrophage (macro 5 large, phage 5 eat).
As the name suggests, a macrophage is a large eater of
microorganisms, foreign material, and dead cells. This
Mast cell is irritated causing
histamine to be released
Cellular Response
Neutrophil death
(pus)
Macrophage invasion
and cleanup
Vascular Response
Figure 4-2 Acute inflammation—cellular and vascular response.
cell might be considered the tank of the war because it
is slower moving but has more killing power than the
neutrophil. Another job of the macrophage is to act as
the cleanup crew, removing the dead neutrophils and
tissue debris in the inflamed area.
Until this point, the inflammation is considered an
acute (short-lived) situation. If the inflammation persists
for a longer period, it is considered a chronic problem.
This time is difficult to establish because some chronic
inflammations will exhibit periods of exacerbation
(flare-up), eliciting a new outpouring of neutrophils.
Likewise, some acute inflammations will trigger the
response of an unusually high number of macrophages.
After approximately 7 to 10 days, if the inflamma
tory process has not overcome the invader, the nuclear
warheads of the defense system—the lymphocytes—
are called on to respond. Lymphocytes are slow but
powerful, specific killers, part of the body’s third line
of defense: the immune response. They identify the
enemy, make an antibody to kill it, and then remember
the enemy and the killing process (see Figure 4-1). Refer
to Chapter 5, “Immune System Diseases and Disorders,”
for more detailed information on the immune system.
Chronic Inflammation
Generally, a chronic inflammation can be considered
one that lasts 2 weeks or longer. If the acute attack by
neutrophils and macrophages is unsuccessful, the bat
tle can become chronic. Microscopic examination of
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