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Endocrine System Diseases and Disorders 297
This is especially true if the HbA1C level remains high
for long periods of time.
The closer the HbA1C is to normal, the lower the
risk for complications. A normal HbA1C is 5% or less.
Results above 7% indicate that diabetes is poorly con
trolled. Managing blood glucose levels and bringing
the HbA1C level down decrease the risk of long-term
complications. Testing is recommended every three to
six months.
■ Prevention. Type 1 diabetes has a hereditary etiology
and cannot be prevented. Research has demonstrated
that people at risk for type 2 diabetes can prevent or
delay developing type 2 diabetes by losing weight and
exercising.
Gestational Diabetes
■ Description. Gestational diabetes is a type of diabetes
that occurs only during pregnancy. It is usually short
lived, with blood sugar levels returning to normal soon
after delivery.
■ Etiology. During pregnancy, the placenta produces
estrogen and progesterone to maintain pregnancy.
These hormones make the body cells more resistant to
insulin. The mother’s pancreas usually produces more
insulin to overcome this resistance. As the placenta
grows, more hormones are produced, placing more
demand on the pancreas. If the pancreas reaches a point
at which it cannot produce enough insulin to meet the
need, less glucose moves into the body cells, and blood
glucose levels rise. The developing fetus is also affected
by the hyperglycemia and is usually overweight at birth.
■ Symptoms. The condition can present the same
symptoms as DM or be asymptomatic.
■ Diagnosis. This type of diabetes is usually discovered
with routine urine testing during prenatal visits. Further
testing may include a two- or three-hour postprandial
test. This test is a measurement of blood glucose lev
els at two or three hours after the individual has eaten.
Normally, the blood sugar level will be down to normal
in two to three hours after a meal. It is important to
discover this condition and treat it because, otherwise,
it can lead to fetal or neonatal mortality.
■ Treatment. Gestational diabetes is treated, like DM,
with exercise, dietary control of carbohydrate intake,
and medications. Injectable insulin might be needed to
control blood sugar levels. Oral hypoglycemic medica
tions are contraindicated because these pass across the
placenta and can lead to fetal birth defects or hypoglyce
mia. Gestational diabetes usually disappears after deliv
ery. If this condition does not disappear after delivery,
the affected individual will need to continue diabetic
management. Women affected with gestational diabetes
are often affected later in life by adult-onset diabetes.
■ Prevention. There is no absolute prevention, but those
who observe a healthy lifestyle and a normal weight at
conception are at less risk of developing the condition.
Hypoglycemia
■ Description. Hypoglycemia (HIGH-poh-gly-SEE-
me-ah; hypo = decreased, glyc = glucose, emia = blood)
is an abnormally low blood sugar level. Hypoglycemia
occurs whenever the blood glucose level drops below
Complementary and Alternative Therapy
Acupuncture
for Diabetic
Neuropathy
D
iabetic neuropathy is a type of nerve damage that can occur in almost anyone with
diabetes. It affects some individuals and does not affect others. The symptoms are
pain and numbness in the feet and lower legs and sometimes even in the hands. Many
individuals with neuropathy describe feeling “pins and needles” in their feet and legs.
Others may describe it as a feeling of tingling and burning. It is one of the most common
complications of diabetes. One study demonstrated that acupuncture can be an effective
treatment for diabetic neuropathy in some individuals. It has few side effects than many
of the pharmaceutical medicines used to treat the condition. Larger studies of the treat
ment modality are needed to demonstrate the values of using acupuncture for treatment
of diabetic neuropathy.
Source: Ugradar (2020)
298 Chapter 14
60 mg/dl, although individuals can become symptom
atic at different blood glucose levels. Some individuals
tolerate unusually low blood glucose levels, whereas
others do not.
■ Etiology. Some common causes of hypoglycemia are
fasting, skipping meals, and excessive exercise. Hypo
glycemia is also caused by administration of too much
insulin, as previously discussed. Other causes of hypo
glycemia include pancreatic adenoma, gastrointestinal
disorders, and some hereditary disorders.
■ Symptoms. Symptoms are the same as previously
discussed for diabetes and include lightheadedness,
diaphoresis, and trembling. If untreated, symptoms can
progress to include mental confusion and coma. Most
individuals have had an episode of hypoglycemia at one
time or another.
■ Diagnosis. Physical examination to observe symp
toms and blood glucose testing aid in the diagnosis.
Blood testing may include a five-hour glucose tolerance
test (GTT). This test is performed in the same manner
as the three-hour test with an additional two hourly
blood draws. A blood glucose level of less than 70 mg/
dl at the time of symptoms and relief after eating con
firm the diagnosis.
■ Treatment. Treatment of hypoglycemia is depen
dent on cause. Diabetics should carry glucose tablets or
candy to take at the first sign of hypoglycemia. Acute
hypoglycemia needs immediate emergency treatment
with intravenous glucose administration.
■ Prevention. Preventive measures include eating a
well-balanced diet, eating small meals often, keeping
snacks available, avoiding sugary foods on an empty
stomach, avoiding drinking alcohol on an empty stom
ach, keeping body weight at a healthy level, not smok
ing, and maintaining an exercise program.
Reproductive Gland Diseases
Sexual development can be affected by the release of
androgens from the adrenal cortex, as previously dis
cussed; by the pituitary; and by the sex organ (gonad).
The male gonad is the testis, and the female gonad is
the ovary. Gonads function as endocrine glands in the
production of hormones, and the pituitary controls
the function of the gonads by releasing gonadotropin.
Gonadotropin stimulates the testes to produce the male
hormone, testosterone, and the ovaries to produce the
female hormone, estrogen. Dysfunction of the pituitary
or the gonad can lead to endocrine disorders.
Hypergonadism
■ Description. Hypergonadism is the condition of
increased hormone production before puberty, which
produces precocious sexual development in both sexes.
■ Etiology. Causes of hypergonadism include unknown
causes, testicular tumors, and pituitary tumors. Hyper
gonadism in females is primarily due to idiopathic
causes. Uncommon causes include ovarian and adrenal
tumors.
■ Symptoms. In the male, onset of puberty usually
occurs around age 13; with hypergonadism, this devel
opment occurs before age 10.
Signs of precocious sexual development in the male
include the following:
■ The growth of a beard and pubic hair
■ Enlargement of the penis and testes
■ Spermatogenesis, rendering the individual fertile
■ Rapid growth of muscle and bone, leading to early
uniting of the epiphyses and a premature halt of
long bone growth
In the female, onset of puberty usually occurs
around age 10; with hypergonadism, this development
occurs before age 8. Signs of precocious sexual develop
ment in the female include the following:
■ Onset of menarche
■ Appearance of pubic and underarm hair
■ Breast enlargement
■ Ovarian development, rendering the individual fer
tile and making pregnancy possible
■ Diagnosis. Diagnosis of hypergonadism is confirmed
by positive clinical history and blood testing for evi
dence of elevated sex hormones.
■ Treatment. Treatment for both sexes involves removal
or radiation of tumors and administration of hormones
to suppress or counteract the sex hormone.
■ Prevention. There is no known prevention for
hypergonadism.
Hypogonadism
■ Description. Hypogonadism is the condition of
decreased sex hormone production by the age of nor
mal puberty.
■ Etiology. In the male, causes of hypogonadism
include dysfunctional testes, undescended testes, or loss
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Endocrine System Diseases and Disorders 299
of the testes due to castration. Testes also might fail to
develop due to a pituitary disorder, resulting in the lack
of gonadotropin. In the female, causes of hypogonadism
include missing or dysfunctional ovaries.
■ Symptoms. Loss of the male gonads before puberty
causes eunuchism, or the lack of development of sex
characteristics, because male characteristics are brought
about by testosterone. Castration of a man will lead to a
decrease in libido, but masculinity is maintained.
Without estrogen, female sex characteristics do
not develop. Female children become abnormally tall
because the long bones do not fuse normally without
estrogen.
■ Diagnosis. Hormone testing for males includes tes
tosterone, thyroid level, and sperm count. For females,
hormone testing of estrogen, FSH, LH, prolactin, thy
roid, and anemia aid in diagnosis. If pituitary disease
is suspected, an MRI or CT scan of the brain might be
needed.
■ Treatment. Administration of testosterone is quite
effective in treating hypogonadism in the male, and
administration of estrogen is quite effective in treating
hypogonadism in the female.
■ Prevention. Most cases cannot be prevented, but
maintaining a healthy body weight and lifestyle might
aid in prevention.
Trauma
Head injury can lead to multiple-organ dysfunc
tion if the pituitary is involved. Hypersecretion and
hyposecretion can occur with injury to any of the
individual organs. Organ destruction and failure can
be life-threatening when the pituitary, pancreas, and
adrenal glands are all involved.
Rare Diseases
Most previously discussed diseases of the endocrine
system are relatively uncommon, with the exception
of thyroid problems and DM. Other extremely rare
endocrine disorders can be found in children or young
adults, however. Cancer of most of the glands of the
endocrine system is also somewhat rare, although the
thyroid, ovaries, and testes are the most common sites
for cancer development.
Effects of Aging on the System
As the individual ages, changes occur in the endocrine
glands. Decreases in the secretions from the glands alter
the body’s ability to respond to stressors, diseases, and
other changes that occur from aging. The older adult is
at high risk for hypoglycemic reactions and excessive
fluid loss due to reduced levels of glucocorticoids and
aldosterone. Digestive and metabolism problems are
common due to reduced secretions of pancreatic and
thyroid hormones. The secretions from the gonads are
reduced, resulting in changes in secondary sex charac
teristics. Because glucose tolerance lessens with age, the
serum glucose levels tend to be higher in the older adult.
DM is common in the older population but usually can
be regulated by dietary adjustments. With all the other
changes that occur during the aging process, diabetes
becomes a very serious condition, adversely affecting
many systems.
Summary
T
he endocrine system is a complex system of many glands located throughout the body. Each of the glands has a
unique function and delivers its hormones into the bloodstream. The hormones help the body’s growth, regulation,
and metabolism. Overproduction or underproduction of any one gland can cause dysfunction in other systems. If the
gland malfunctions in childhood, the result is a different disorder than if the gland malfunctions in adulthood. The
most common endocrine disorder overall is DM. Although, historically, type 2 diabetes was most commonly found in
middle-aged or older adults, it is now frequently diagnosed in younger populations and is related to the increasing rate
of obesity in the population. The older adult with an endocrine disorder is at risk for other systemic problems. Secretions
from the endocrine glands decrease slowly with age.
300 Chapter 14
Review Questions
Short Answer
1. What are the functions of the endocrine system?
2. Which signs and symptoms are associated with common endocrine system disorders?
3. Which diagnostic tests are most commonly used to determine the type and cause of endocrine system disorders?
Multiple Choice
4. Which of the following is not an endocrine gland?
a. Pituitary
b. Adrenal
c. Liver
d. Ovaries
5. What function does the somatotropin hormone perform?
a. Promotes absorption of calcium in the bones
b. Stimulates the thyroid to produce its hormones
c. Stimulates growth
d. Promotes development of sex characteristics
6. Acromegaly is defined as which of the following?
a. An overgrowth of the long bones of the body
b. An abnormal decrease in the activity of the pituitary gland
c. A tumor located in the anterior pituitary
d. A chronic disorder characterized by large feet, hands, and facial bones
7. Cretinism is defined as which of the following?
a. Congenital hypothyroidism
b. Congenital hypopituitarism
c. Severe chronic lack of growth hormone
d. An impaired growth of all body parts
8. Hypoadrenalism is also known as which of the following disorders?
a. Acromegaly
b. Myxedema
c. Cushing’s syndrome
d. Addison’s disease
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Endocrine System Diseases and Disorders 301
9. In type 1 DM, the individual needs replacement of which of the following?
a. Steroids
b. Antidiuretic hormone
c. Insulin
d. Estrogen
10. The individual affected by type 2 DM can usually control the disorder by:
a. Insulin injections
b. Diet and oral medications
c. Replacement hormones
d. Steroid therapy
Matching
11. Match the hormone in the left column with its gland in the right column. Some glands may be used more than
once.
ACTH a. Anterior pituitary
T3 b. Posterior pituitary
Oxytocin c. Pineal
Mineralocorticoids d. Thyroid
Melatonin e. Adrenals
Estrogen f. Testes or ovaries
Insulin g. Pancreatic islets
Norepinephrine
ADH
Calcitonin
Fill in the Blank
12. Hyperpituitarism in the adult results in __________ .
13. Polyuria is a common symptom of __________.
14. A deficiency in glucocorticoids lowers blood sugar levels leading to ___________ .
15. An enlargement of the thyroid gland is called a __________ .
16. The ovaries secrete estrogen and _________ .
True or False
17. T F There is a decrease in secretion from the endocrine glands as the individual ages.
18. T F Older adults often have digestive problems due to changes in the system.
19. T F Glucose tolerance increases with age.
20. T F Type 2 diabetes is common in older adults.
302 Chapter 14
Case Studies
■ Ms. Jenson is a young woman who has been diagnosed with exophthalmos by her eye doctor. She seems
very confused about this diagnosis. How could you explain this to her? She said the doctor told her she has
Graves’ disease. What is Graves’ disease? What is the treatment for it?
■ Mrs. Webb is 78-years-old and has been diagnosed with type 2 diabetes. She has repeatedly complained
about tingling and burning in her feet. She also states she is now having difficulty walking because her feet feel
numb. What would be your response to her? What can be done to alleviate this?
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15
Nervous System
Diseases and
Disorders
Key Terms
Amnesia (p. 326)
Aura (p. 316)
Carotid endarterectomy
(p. 315)
Cauterization (p. 329)
Cephalalgia (p. 316)
Chorea (p. 330)
Convulsion (p. 317)
Decompress (p. 330)
Dysphagia (p. 313)
Dysphasia (p. 313)
Epidural (p. 328)
Focal onset seizures
(p. 317)
Generalized onset
seizures (p. 317)
Hemiparesis (p. 313)
Hydrophobia (p. 310)
Hypothermia (p. 329)
Intractable (p. 316)
Nuchal rigidity (p. 309)
Paraplegia (p. 329)
Paresthesia (p. 330)
Quadriplegia (p. 329)
Seizure (p. 317)
Spinal stenosis (p. 316)
Status epilepticus (p. 317)
Subdural (p. 329)
Learning Objectives
Upon completion of the chapter, the learner should be able to:
1. Define the terminology common to the nervous
system and the disorders of the system.
2. Discuss the basic anatomy and physiology of the
nervous system.
3. Identify the important signs and symptoms
associated with common nervous system disorders.
4. Describe the common diagnostics used to determine
the type and cause of nervous system disorders.
5. Identify common disorders of the nervous system.
6. Describe the typical course and management of
the common nervous system disorders.
7. Describe the effects of aging on the nervous
system and the common disorders associated with
aging of the system.
Overview
T
he nervous system is a complex network that provides communication from the brain to the rest of the
body and from the body back to the brain. It facilitates the individual’s ability to reason, interact with
other individuals, understand complex ideas, and respond both intellectually and physically. Disorders of
the system can affect any or all other normal functioning in the individual. Because brain and spinal cord
injury often causes irreversible damage, the individual with a nervous system disorder can become a victim
of severe, permanent, neurologic deficits. ■
303
Consider This...
The brain stops growing at approximately
age 18.
Anatomy and Physiology
The nervous system is composed of the brain, spinal
cord, and nerves (Figure 15-1). It is divided into the
central nervous system (CNS) and the peripheral ner
vous system (PNS). The CNS includes the brain and the
spinal cord. The PNS includes the autonomic nervous
system (ANS), the cranial nerves, and the spinal nerves.
The CNS communicates with organs and other body
systems through the PNS.
Spinal
cord
Brain
Central
- nervous
system (CNS)
Peripheral
nerves
+
Sensory
receptors
sensations
peripheral
nerve
The Central Nervous System
The brain is a complex structure located within the
protective covering of the skull. It is divided into the
cerebrum, cerebellum, and brain stem. The cerebrum
is divided into two hemispheres that can be further
subdivided into lobes. Each of these lobes has a special
ized function (Figure 15-2). The basal ganglia, called
the gray matter, are located deep in the hemispheres.
Another part of the cerebrum is called the dienceph
alon. This is where the hypothalamus and thalamus
are located. They are active in controlling the body’s
sleep-wake pattern and are involved in the actions
of the hypophysis (pituitary) gland. (See Chapter 14,
“Endocrine System Diseases and Disorders,” for more
information.)
The cerebellum, important in coordination and
fine motor movements, is located in the lower back part
of the brain.
The brain stem makes up the last part of the brain.
It is subdivided into the midbrain, pons, and medulla;
contains some nerves; and is responsible for trans
mitting impulses that control respiration, swallowing,
wakefulness, and other activities.
A
The brain holds five times as much informa
tion as the Encyclopedia Britannica, or the
equivalent of 1,000 computer terabytes.
Consider This...
Figure 15-1 The nervous system.
Peripheral
nervous system (PNS)
The spinal cord is a continuous structure running
through the vertebral column from the medulla to the
tailbone. The spinal cord is composed of both white
and gray matter. It has ascending and descending path
ways that transmit impulses. Sensory impulses (pain,
temperature, and touch) travel from the spinal cord to
the brain. Motor impulses (for movement of muscles)
travel from the brain to the spinal cord.
stimulus
sensory
receptors Consider This...
Pain travels through the body at a speed of
350 feet per second.
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Nervous System Diseases and Disorders 305
Sulci
Convolutions of
cerebral hemisphere
(gyri)
Frontal lobe
Temporal lobe
Cerebellum
Midbrain
Brainstem Pons
Medulla
Parietal lobe
Occipital lobe
Cerebrum
Lateral View
Emotions I
Personality
Morality
Intellect X
Speech
Sensory
Motor _
Pain
Heat
Touch --
Hearing
Vision
Smelling
Relays impulses
Autonomic nervous control
Control blood pressure
Maintain body temperature
Stimulates antidiuretic hormone
Assists with appetite regulation
Acts on intestines
Role in emotions
Eye reflexes^
Conduct impulses
Breathing
Chewing
Taste
iscle tone
uilibrium
lking
ncing
Heart
Lungs
Stomach
Blood vessels
Helps maintain wakefulness
Figure 15-2 The cerebral lobes and their specialized functions.
The meninges are membranes that cover the brain
and spinal cord. The meninges are divided into three
layers: the dura mater (outer cover), the arachnoid
(middle layer), and the pia mater (inner layer). They
provide both protection and support for the system.
The Peripheral Nervous System
The ANS controls the functions of the body’s organs
and innervates smooth muscle and cardiac muscle. It is
divided into the parasympathetic and sympathetic sys
tems. The parasympathetic system controls the changes
in the body needed to relax and restore function, such
as returning blood pressure to normal after it has
increased in response to some need. The sympathetic
system controls the changes in the body needed to
respond to stressors, such as increasing the heart rate
or blood pressure—the fight-or-flight response.
Twelve pairs of cranial nerves control sensation and
movement in the area of the head and neck (Table 15-1).
Thirty-one pairs of spinal nerves are divided into eight
cervical, twelve thoracic, five lumbar, five sacral, and one
coccygeal. Each spinal nerve innervates designated areas,
called dermatomes, of the skin (Figure 15-3). Each of
the spinal nerves sends sensory impulses from the body
organs and surfaces to the spinal cord for transmission
306 Chapter 15
TABLE 15-1 The Cranial Nerves
Cranial Nerve Function
I. Olfactory Smell
II. Optic
Sight
III. Oculomotor Movement of the eyeball, pupil, and eyelid
IV.Trochlear Movement of the eyeball
V.Trigeminal Chewing; pain, temperature, and touch of face and mouth
VI. Abducens Movement of the eyeball
VII. Facial Movement of the face and secretion of saliva; taste
VIII. Auditory Hearing and balance
IX. Glossopharyngeal Swallowing and secretion of saliva; taste and sensation in the mouth and pharynx
X. Vagus Sensation and movement in the pharynx, larynx, thorax, and gastrointestinal system
XI. Accessory Movement of the head and shoulders
XII. Hypoglossal Movement of the tongue
C-2
Figure 15-3 Spinal nerves and dermatomes.
to the brain and returns motor impulses from the brain
to the spinal cord and then to the muscles.
Consider This...
Twenty-five percent of the brain is used to
control the eyes.
Common Signs and Symptoms
Common signs and symptoms of nervous system dis
orders include headache, nausea, vomiting, weakness,
mood swings, and fever. Symptoms specific to the ner
vous system include the following:
■ Disturbance in motor function (or ability to move),
including:
1. Stiffness in the neck, back, or extremities
2. Inability to move any part of the body
3. Seizures or convulsions
4. Paralysis
■ Disturbance in sensory function (or ability to sense
or feel), including:
1. Visual difficulties
2. Inability to speak
3. Paralysis
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