Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3098_Библиотеки_им_академика_М_И_Перельмана
.pdf
11 - Gastrointestinal Disorders and Nutrition |
307
D D
Aging leads to structural weakness in the colon
muscle, predisposing the elderly to diverticular
disease. The prevalence of diverticular disease
increases from 5% or less in those under age
40 to 65% for individuals over 65.
148
Admissions
for acute diverticulitis in the United States have
increased by 26% from 1998 to 2005.
149
The
primary risk factor for diverticular disease is a
low dietary fiber intake; thus, it is considered
a disease of westernized nations. Diagnosis
of diverticular disease is most often made on
computed tomography; however, barium enema
or colonoscopy may also be used in a stable
patient.
Diverticulosis refers to the presence of
diverticula, or saclike herniation of the colonic
mucosa through the muscle, whereas diverticu-
litis describes an inflammation of one or more
diverticula. It is estimated that 80% to 85% of
patients with diverticula are asymptomatic.
Hemorrhage may occur in 20% of patients and
is the most common cause of hematochezia
in older adults.
150,151
However, acute diverticu-
litis may cause abdominal pain, bloating, and
a change in bowel habits. In addition, for more
severe cases of diverticulitis, signs of inflamma-
tion such as fever and leucocytosis are present.
Acute diverticulitis may be complicated by
abscess formation, fistulas, intestinal obstruc-
tion, or free perforation with peritonitis. Although
perforation is rare, it carries a high mortality
of 35%.
148
The need for hospital admission is
dictated by severity of presentation, comorbidity,
and ability to tolerate oral hydration. When acute
diverticulitis occurs twice per year or more, it is
referred to as recurrent.
A diet high in insoluble fiber is first-line therapy.
Insoluble fiber from fruits and vegetables is
preferred to that from cereal fibers.
148,151
Fiber
supplementation can be utilized in those unable
to comply with dietary changes, although no
large controlled trials support these treatments.
A common dose is 30 g of insoluble fiber per
day.
150
Historically, diets with nuts, corn, or seeds
were forbidden in patients with diverticula for fear
the particles would lodge in the sac and cause
inflammation. However, no data support this
pathology, so patients should not be restricted
in this manner.
151
Uncomplicated symptomatic diverticular
disease may also be treated with a monthly
regimen of rifaximin 400 mg twice daily for 10
days or mesalazine 400–800 mg twice daily
for 7–10 days. These treatments are off-label
but supported by small randomized, controlled
trials and are generally reserved for patients with
recurrent disease or ongoing symptoms.
152
Severe hemorrhage may occur in 3% to 5%
of patients and is more commonly seen in those
taking NSAIDs or who are immunocompromised.
The bleeding is arterial, usually painless, and
should be treated with fluid and blood products
as indicated. Bleeding will cease spontaneously
in 70% to 80% of patients.
Acute diverticulitis is treated with a clear
liquid diet in those patients who are stable
and able to tolerate oral intake. A 7–10 day
course of metronidazole in combination with
trimethoprim/sulfamethoxazole or ciprofloxacin
is recommended to cover most anaerobes and
gram-negative aerobes. Improvement should
be seen in 2–4 days, at which time the diet
may be advanced as tolerated. For individ-
uals with more severe disease or who cannot
tolerate oral intake, hospitalization is indicated
for monitoring electrolyte balance and for more
aggressive treatment. These patients should be
treated with intravenous fluids and parenteral
antibiotics. Coverage of colonic anaerobic and
gram-negative flora is needed for 7–10 days.
151
Pain management may also be needed with
opiate analgesics. Again, clinical improvement
is expected within 2–4 days, at which time a diet
may be started and the patient converted to oral
https://t.me/medicina_free
308
| Fundamentals of Geriatric Pharmacotherapy
antibiotics. Surgical treatment may be neces-
sary in a small subset of patients who develop
complications. Elective surgery, sometimes with
laparoscopic techniques, is used in patients with
recurrent disease after the acute episode has
been controlled for several weeks.
148,150
KEY POINT:
NSAIDs are associated with
an increased risk of bleeding and perforation
in patients with diverticular disease.
Few randomized controlled clinical trials are
available to support current treatment recom-
mendations for diverticular disease. Trials evalu-
ating the effectiveness of fiber were primarily
performed in the 1970s and 1980s and involved
small numbers of patients with uncomplicated
symptomatic disease.
152
Recent meta-analyses
indicate rifaximin and mesalamine can provide
significant reduction in global symptoms and
may reduce acute episodes of diverticulitis.
However, most studies were limited to patients
age 40–80, and there is a possibility that patients
who had irritable bowel syndrome concurrently
with diverticular disease were included in the
trials.
152,153
Nevertheless, the number needed
to treat for rifaximin in symptomatic diverticular
disease is reported as 3 for symptom relief and is
59 for reduction in complication rate.
153
Elderly patients with diverticular disease are
more likely to be hospitalized than younger
patients because of their significant risk for
comorbidity. Surgery is required in 15% to 30%,
which carries an additional risk of complications
and mortality. Although rare, free perforation with
peritonitis carries a mortality rate of 35%. Both
perforation and hemorrhage have been associ-
ated with NSAIDs, which are frequently used in
older patients.
152
Antispasmodics are sometimes listed for
symptom control of diverticular disease because
of their ability to diminish muscular contraction.
However, no controlled trials document their
benefit, and given their anticholinergic adverse
effects, they should be avoided in elderly
patients.
C
Constipation is associated with a decrease in
functional ability and quality of life.
154
Symptoms
or patient complaints include straining, lumpy
or hard stools, sensation of incomplete evacu-
ation, sensation of obstruction or blockage, and
manual maneuvers to facilitate defecation.
155
Whereas approximately 12% of individuals in
North America report having had chronic consti-
pation, the prevalence increases to 16% to 26%
in patients over age 65 and further increases
to 26% to 34% in patients over age 84.
156,157
A more striking statistic is that 50% to 79% of
nursing home residents have constipation and/
or take a laxative on a daily basis.
155
Prevalence
varies due to the different definitions of consti-
pation. It was once defined as fewer than three
bowel movements per week, whereas the defini-
tion now includes hard stools and straining. The
latter is often more important to patients who may
continue to complain of constipation if they strain
or have hard stools, regardless of the number of
bowel movements they have in a week. On the
other hand, some patients erroneously believe
that a daily bowel movement is important for
colon health and request laxatives to achieve
this goal.
157
In addition to the symptoms of straining,
incomplete evacuation, and hard stools, patients
may have abdominal pain, dysuria, and incon-
tinence (both fecal and urinary). Delirium or
agitation may be the presenting symptom, most
often seen in patients with degenerating mental
illnesses. Complaints of anorexia and nausea
https://t.me/medicina_free
11 - Gastrointestinal Disorders and Nutrition |
309
can be associated with constipation, especially if
fecal impaction develops. Bed-bound patients
who are unable to express complaints may react
to the discomfort of constipation by fingering,
rubbing, or scratching the anus, resulting in the
unhygienic spread of stool.
Primary constipation may be caused by
disordered defecation, where the relaxation of
the pelvic floor and the sphincters during the
process of defecation is not coordinated. Another
primary cause is slow transit constipation, identi-
fied by use of radio-opaque pills or a wireless
motility capsule that measures colonic transit
time, pH, temperature, and pressure. However,
the most common type of primary constipation
in elderly patients is functional constipation.
There are many secondary causes of consti-
pation. Lifestyle factors, such as a diet poor in
fiber or low activity levels, are common. Meta-
bolic, endocrine, or GI diseases; neurogenic
or psychogenic disorders; and medications
are frequently cited. These underlying factors
must be carefully assessed because they guide
subsequent management.
Standard treatment in the
a
dult PoPulation
Clinical evaluation starts with the patient’s
description of his or her constipation. Specific
alarm symptoms include hematochezia, melena,
family history of colon cancer or inflammatory
bowel disease, anemia, weight loss, nausea,
and vomiting.
157
Patients reporting any of these
conditions may require additional evaluation
with colonoscopy for underlying life-threatening
conditions. However, these symptoms are
uncommon with typical chronic constipation.
A rectal examination may identify sphincter
or pelvic floor abnormalities associated with
disordered defecation. Laboratory testing is not
routinely necessary unless a specific organic
disorder is suspected. Correction of underlying
diseases that contribute to constipation should
be attempted.
157
The best treatment for constipation in younger
adults is prevention through increased dietary
consumption of fruits, vegetables, and cereals.
Dietary habits should be thoroughly scrutinized
to identify the usual amount of fiber consumed.
Over-the-counter bulk-forming laxatives may be
used to supplement dietary fiber. Stool softeners
may aid patients with hard stools or straining.
Although some evidence supports supplementa
-
tion of the diet with bran, yogurt, or psyllium, the
data are not strong. Similarly, the use of docusate
has not been shown in well-controlled trials to
improve the number of stools or their consistency.
However, these lifestyle changes and medications
are generally well tolerated, and many patients do
report favorable results.
155
If a patient has not had a bowel movement
in the past 3–4 days, acute relief is needed. This
may be obtained most quickly with stimulants or
enemas. The osmotic agents (lactulose, magne-
sium hydroxide, polyethylene glycol) have fair-
to-good studies supporting their effectiveness
and offer fairly rapid results, usually within 6–12
hours.
155
However, these agents are not without
risk, so patients should be taught that lifestyle
changes are the primary method of prevention
and treatment of constipation, and stimulant
or osmotic laxatives should only provide acute
relief.
Lubiprostone is a chloride channel activator
that stimulates fluid secretion into the colon.
Clinical trials in adults show an increase in stool
frequency and a reduction in straining and consti
-
pation severity. However, it is relatively expensive
when compar
ed to other laxatives and is primarily
used in refractory constipation. The opioid
receptor antagonists alvimopan and methylnal
-
trexone are also expensive and used primarily in
hospitalized patients after surger
y or in palliative
care. They offer the advantage of not crossing
the blood-brain barrier, so they do not counteract
analgesia or precipitate withdrawal.
157
Special circumstances dictate specific
treatments. Individuals taking opiate analge-
sics or with neurogenic causes of constipation
will require routine use of stimulant laxatives.
https://t.me/medicina_free
310
| Fundamentals of Geriatric Pharmacotherapy
Individuals with disordered defecation may
respond to biofeedback therapy, so that as coor-
dination improves over time, laxative use can
be reduced.
158
Of course, a thorough assess-
ment of medications that contribute to constipa-
tion should be performed and steps to stop or
decrease doses, when appropriate, should be
implemented.
Assessment of elderly patients for constipation
should include evaluation for depression, hypo-
thyroidism, hypercalcemia, hypermagnesemia,
and GI bleeding. Any identified diseases that
can contribute to constipation should be appro-
priately managed.
154
In guiding treatment, clini-
cians should consider whether fecal impaction
is present.
159
KEY POINT:
Fecal impaction is
linked to delirium and can progress to
intestinal obstruction if left untreated.
Elderly patients have been represented in
most trials of laxatives for treatment of constipa-
tion. Therefore, management in the older popu-
lation closely follows that for younger adults,
especially in healthy community-dwelling elderly
patients. Recommendations for therapy in bed-
bound elderly patients follow a different pathway.
A statistically significant improvement in consti-
pation has not been shown in this subgroup
when treated with fiber, bulking agents, and/
or stool softeners in comparison to placebo.
However, osmotic agents such as polyethylene
glycol, magnesium hydroxide, lactulose, and
sorbitol were superior to placebo in nursing home
residents, including nonambulatory patients.
Placebo-controlled trials are lacking for senna
and bisacodyl in both community-dwelling and
institutionalized older adults. However, they are
still recommended for acute relief of constipa-
tion in older adults and for routine scheduled use
when needed.
154,155
Probiotics such as Lactobacillus and bifido-
bacterium are not currently recommended for
routine use in treatment or prevention of consti-
pation. Although some studies exist, they are
generally not well controlled, and issues with
the viability and variability of the tested product
continue to be raised. Likewise, studies with tradi-
tional Chinese medicines containing hemp seed,
acupuncture, and herb combinations are heter-
ogenous and difficult to apply to practice.
160,161
When performing an assessment of delirium and
agitation in elderly, cognitively impaired patients,
clinicians should consider constipation as a
cause or contributing factor. One study identified
constipation associated with physical aggres-
sion in nursing home residents, with an adjusted
odds ratio of 1.3 (confidence interval 1.2–1.5).
162
An abdominal examination and x-ray to iden-
tify the presence of stool are indicated when a
change in behavior or level of consciousness is
noted.
KEY POINT:
e most important assessment
in elderly patients with constipation
is a medication regimen review.
Iron, opiates, agents with anticholinergic
activity, and calcium channel blockers are
frequent offenders; however, many agents may
contribute. Ferrous sulfate 325 mg should not
be dosed more than once daily because of the
increase in risk for GI problems without substan-
tial increase in the amount of iron absorbed.
Calcium-channel blockers contribute to disor-
dered defecation and have been named the most
common unrecognized cause of constipation.
154
Many elderly patients are seen in the emer-
gency department with fecal impaction because
proper steps to prevent or treat constipation
were not implemented quickly enough. In these
patients, fiber and bulk-forming agents are inap-
propriate. Manual disimpaction, enemas, and/
or suppositories should be utilized to break up
https://t.me/medicina_free
11 - Gastrointestinal Disorders and Nutrition |
311
the hard stool and enable its passage out of
the colon and rectum.
159
Tap water enemas are
preferred, as soap suds enemas have been
linked to rectal mucosal irritation and phosphate
enemas increase the risk for acute kidney injury.
The group of patients most commonly associ-
ated with laxative abuse is young adults with eating
disorders. However, older adults are also likely to
abuse laxatives. In this group laxative use begins
as a legitimate treatment for constipation or is
associated with a belief that good health requires
a daily bowel movement. With daily use, espe-
cially with stimulant laxatives, patients become
dependent. The clinician must identify the patient’s
beliefs regarding bowel movements and laxative
use and provide education where needed. A laxa-
tive withdrawal protocol may be helpful, switching
from stimulant laxatives to fiber and magnesium
hydroxide laxatives. Behavioral therapy may be
needed in conjunction with the changes.
163
F I
Fecal incontinence is the involuntary loss of
liquid or solid stool, although some studies
include flatus, and others further specify that the
loss results in social or hygienic problems. In
addition, 50% to 70% of people with fecal incon-
tinence also report urinary incontinence, and this
combination is the second most common cause
of placement in long-term care facilities.
164
In
community-dwelling older adults, the preva-
lence of fecal incontinence is reported to be as
high as 36% compared to 33% to 65% in elderly
patients residing in nursing homes. Predisposing
conditions in elderly patients include diabetes
mellitus, irritable bowel syndrome, and multiple
sclerosis.
165
Many patients with fecal incontinence are
anxious or embarrassed and will not initiate
discussion about the problem with their health-
care providers, or they may identify it as diarrhea
instead. Passive treatment of fecal incontinence
with use of pads seems to be the usual treatment
for both community-dwelling elderly patients
and nursing home residents. A more rational
approach would include a medical review of
potential causes and treatment tailored to the
cause. The most common cause of fecal incon-
tinence in elderly nursing home patients is fecal
impaction and overuse of laxatives, which can
be controlled and prevented.
In younger adults, fecal incontinence is frequently
the result of trauma, usually from vaginal delivery
or surgery, which causes dysfunction of the
anal sphincters or pelvic floor. Testing of anal
pressures, sensation, or nerve conduction may
be performed to characterize the problem and
guide therapy. Bulking agents such as methyl-
cellulose are used to improve stool consistency.
Antidiarrheal drugs and anticholinergic agents
aid in reducing stool frequency.
Supportive measures include the avoidance
of caffeine, no exercise after eating, ritualizing
bowel habits, and good perineal skin hygiene, as
this care is known to improve symptoms. These
recommendations are also useful in elderly
patients. Biofeedback therapy helps to retrain
the pelvic floor and improve muscle strength
so that a coordinated effort to defecate occurs.
Evidence of effectiveness is controversial, and
patients must be cognitively intact to benefit. In
some instances, injection of collagen, silicone, or
dextranomer/hyaluronic acid around the internal
anal sphincter may be indicated after conser-
vative measures are found to be unsuccessful.
Surgical repair of damage from trauma may be
an option, and colostomy would be considered
a last resort.
165,166
Few high-quality trials are performed in the area
of fecal incontinence, and fewer still include
significant numbers of older subjects. The find-
https://t.me/medicina_free
312
| Fundamentals of Geriatric Pharmacotherapy
ings from the International Consultation on
Incontinence Management of Fecal Inconti-
nence in Adults Committee produced no Grade
A recommendations but relied mainly on expert
consensus for its conclusions. The recommen-
dations include optimization of stool consistency,
consideration of alternative medications in medi-
cation-induced diarrhea, toilet access, educa-
tion of patients and caregivers, bowel training,
and biofeedback in addition to use of laxatives
with impaction or antidiarrheals in diarrhea. In
particular, they note that fecal incontinence in
frail older people should be evaluated through
direct questioning and observation, so that
active treatment can be tailored to the patient.
166
In one open-label study of 82 nursing
home residents from 30 facilities, subjects were
assessed as having fecal incontinence due to
impaction/constipation or due to neuromuscular
dysfunction. Individuals with impaction/consti-
pation received treatment with regular toileting
after meals and lactulose 10 mL twice daily plus
a weekly enema. Individuals with neuromus-
cular dysfunction received regular toileting after
meals and codeine 30–60 mg daily. These two
groups were compared to a control group of 30
patients. The investigators reported a cure rate
of 87% compared to 32% of the control group.
167
Although an older study, this information supports
institution of conservative measures tailored to
the suspected cause of the incontinence.
KEY POINT:
When fecal impaction is treated
with oral laxatives, seepage of stool around the
blockage can occur and mimic incontinence.
Elderly adults are not as likely as younger adults
to have fecal incontinence due to trauma, so
the approach to an older patient is different. A
focused medical history and physical exami-
nation will frequently identify the cause of fecal
incontinence in the elderly patient. In older
adults, the three most common categories that
guide therapy are fecal impaction, diarrhea and
urgency, and neuromuscular dysfunction.
168
The first and most common category is fecal
impaction. Incontinence occurs because impac-
tion produces inhibition of sphincter tone. When
this is coupled with laxative use, seepage of
stool occurs around the blockage. This etiology
is reported in 42% of older adults with inconti-
nence.
164
Its treatment involves manual disimpac-
tion and enemas. After the impaction is resolved,
preventive measures should be instituted, such
as avoidance of constipating medications,
increased mobility, and routine use of laxatives.
The second category includes diarrheas
from infection, colitis, inflammatory bowel
disease, or radiation therapy. Treatment of the
underlying condition will usually resolve the
incontinence. Diarrhea may also result from
use of medications, as shown in Table 11-1.
169
Alternative agents should be considered for use,
when possible. If necessary, treatment with fiber
and antidiarrheals can be implemented. Loper-
amide is preferred over diphenoxylate/atropine
or codeine because of reduced adverse effects.
Table 11-1. Commonly Used Drugs
Causing Diarrhea in Elderly Patients
ANTIMICROBIALS:
Cephalosporins, clindamycin,
penicillins, tetracyclines, quinolones, macrolides,
interferon
CARDIOVASCULAR AGENTS:
Angiotensin-
converting enzyme inhibitors, beta blockers,
digoxin, erythropoietin analogues, furosemide,
hydralazine, quinidine, spironolactone, ticlopidine
CENTRAL NERVOUS SYSTEM AGENTS:
Acetylcholinesterase inhibitors, carbamazepine,
selective serotonin receptor inhibitors,
anticonvulsants
ENDOCRINE AGENTS:
Acarbose, bisphosphonates,
calcitonin, metformin, thyroid hormones
GASTROINTESTINAL AGENTS:
Esomeprazole,
lactulose, sorbitol, magnesium-containing
antacids, metoclopramide, misoprostol, octreotide,
orlistat, polyethylene glycol
OTHER:
Antineoplastic agents, azathioprine,
colchicine, NSAIDs, theophylline
Source: Data from references 165 and 169.
https://t.me/medicina_free
11 - Gastrointestinal Disorders and Nutrition |
313
Finally, anorectal neuromuscular dysfunc-
tion from neuropathy, previous surgery, or
injuries should be considered. In these situa-
tions, it is recommended to use insoluble fiber
to increase the bulk of the stool, with toileting
after meals. The next step is to train the patient
through behavioral therapy or biofeedback if he
or she is able to participate in the process. Injec-
tion procedures and surgical techniques may be
indicated in selected patients.
No matter what type of fecal incontinence is
identified, skin breakdown must be assessed in
the older adult. Presence of moisture may lead
to pressure sores, given the vulnerability of older
skin; these sores are apt to become infected
with organisms introduced by fecal matter. In
addition to frequent diaper changes, preventive
use of zinc oxide or hydrocolloids as a moisture
barrier is indicated.
165
D
C. diff. has been recognized as the culprit in
30% of antibiotic-associated diarrhea cases and
is the most common cause of infectious diarrhea
in hospitalized patients.
170
It is a gram-positive
anaerobic bacillus that can form spores. Its
spore-forming ability can impair efforts to eradi-
cate the infection. Exposure to broad-spectrum
antibiotics allows overgrowth of C. diff. in the
intestine of colonized hosts, causing diarrhea
through formation of enterotoxins that increase
inflammation and friability of the intestinal wall.
The median onset of diarrhea after expo-
sure to C. diff. and antibiotics is 2–3 days. The
diarrhea may be a relatively mild acute onset
of watery stools, or it may include abdominal
cramping, low-grade fever, and leucocytosis. If
the white blood cell count exceeds 15,000 cells/
µL, or the serum creatinine rises more than 150%,
experts identify this as severe infection. Hypoten-
sion, shock, ileus, or megacolon may complicate
C. diff. infections, potentially leading to death.
170
Mild-to-moderate disease lasting <10 days in
older adults is seen in 60% of older adults, but
32% had illness lasting a mean of 18 days, and
8% had severe colitis or other complications.
171
The Centers for Disease Control and Preven-
tion reports an annual incidence of C. diff. infec-
tion of 250,000 hospitalizations each year, with a
mortality rate of 1% to 2.5%. Outbreaks of more
severe disease have been observed during
2002–2006 and were attributed to increases in
fluoroquinolone use and the development of a
particular strain of C. diff. referred to as NAP1/
BI/027. This strain has an increased virulence and
a higher level of resistance to fluoroquinolones.
Rates of hospital discharge with a diagnosis of
C. diff. infection are more than fivefold higher for
individuals over 65 than for those age 45–64.
170
The most important risk factor for C. diff.
infection is advanced age. This may be partly
due to the age-related effects on immune
defense, including decreased gastric acidity,
diminished antibody response to toxins, and
impaired phagocytosis.
171
An important modifi-
able risk factor is exposure to antibiotics, iden-
tified in over 96% of cases. Clindamycin and
cephalosporins are more associated with C. diff.
diarrhea than other antibiotics, but any broad-
spectrum antibiotic or combination of antibiotics
will predispose a patient to develop C. diff. infec-
tion. Additional risk factors are hospitalization or
residence in a nursing home or skilled nursing
facility. Somewhat controversial is whether use of
PPIs or H2RAs increases risk for C. diff. infec-
tion. Theoretically, the lack of stomach acid may
allow passage of C. diff. or its spores through the
stomach without being destroyed, thus predis-
posing the patient to infection. PPIs have been
associated with recurrent disease, but studies
for initial infection are less convincing, probably
due to the confounding use of antimicrobials in a
high percentage of patients. For the risks associ-
ated with PPIs and C. diff. diarrhea, see Gastro-
esophageal Reflux Disease in this chapter.
172
Nonpharmacologic treatment begins with
discontinuing predisposing antibiotics and
https://t.me/medicina_free
314
| Fundamentals of Geriatric Pharmacotherapy
institution of infection control measures. Use of
gloves and gowns on entry into the room, with
patients moved into a private room for the dura-
tion of the diarrhea, is recommended. Hand
hygiene must include washing with soap and
water or chlorhexidine and water. Alcohol-based
sanitizers are not able to remove spores from the
hands as effectively as physically removing the
spores with soap and running water.
170
KEY POINT:
Handwashing with soap and
water is most important in preventing the
spread of
Clostridium dicile
and its spores.
Pharmacotherapy for first occurrences of
mild or moderate disease is oral metronidazole
500 mg three times daily. If oral therapy is not
possible, intravenous treatment is acceptable
because the drug is secreted into the intestines
while diarrhea is occurring. Vancomycin 125 mg
orally four times a day may be used for indi-
viduals who cannot tolerate metronidazole, for
severe disease, or for nonresponse. However,
intravenous vancomycin is not effective because
the drug does not reach concentrations through
this route that will eradicate C. diff. in the stool.
Therapy should be continued for 10–14 days.
For first recurrences, treatment is the same
as for initial disease. However, for subsequent
occurrences, vancomycin is the drug of choice.
Experts also recommend a taper/pulse regimen
to aid in eradication of C. diff. in patients who
have recurrences. For a taper dose, after 14 days
of full dose, the vancomycin may be decreased
to 125 mg three times a day for 7–14 days, and
then to twice a day, and then to once a day. At
the end of the taper, a switch to pulse dosing of
125 mg daily for 3 days each week for 3–8 weeks
can be added.
170,172
Metronidazole secretion into
the intestine is minor after diarrhea resolves;
therefore, it is not appropriate to use it in a
taper/pulse regimen.
Fidaxomicin is a nonabsorbable macro-
cyclic antibiotic with Food and Drug Administra-
tion approval for the treatment of C. diff. infection
in adults. It offers an alternative to metronida-
zole and vancomycin. In comparison with oral
vancomycin, fidaxomicin had a lower rate of
recurrence. At present, due to its cost, the drug
is not considered first-line therapy but may be
used if a patient has a high risk for recurrence
and rehospitalization.
172
Additional alternatives
include nitazoxanide, rifaximin, and tigecycline.
Some data indicate that rifaximin may offer an
advantage to prevent C. diff. diarrhea recur-
rence. Intravenous tigecycline has been shown
effective in a case series of patients with severe
refractory disease and, thus, offers a parenteral
alternative to metronidazole.
Most studies in the treatment of C. diff. infec-
tion generally include subjects over age 65, as
the disease is highly prevalent in the elderly. For
example, testing of the new agent fidaxomicin
was performed with 50% of subjects over age
65 and 31% over age 75.
173
However, individuals
with life-threatening disease or toxic megacolon
were excluded. A primary reservoir of C. diff.
are long-term care facilities. Several reports of
environmental contamination and outbreaks in
nursing homes provide evidence of this.
171
As noted, older age is the most frequently
named risk factor for C. diff. infection, with an
incidence in hospitalized adults over the age
of 65 years old 5–10 times as high as younger
adults. Elderly patients are frequent recipients
of antibiotics and experience prolonged insti-
tutionalization. Use of feeding tubes and acid-
suppressant medications may contribute to their
risk of C. diff. infection. The severity of infection
in the elderly is dramatically higher probably
because of comorbid conditions and age-related
changes in host defenses. The most frequently
identified cause of acute infectious diarrhea in
the nursing home is C. diff., and guidelines for
hospitals have been adapted to provide recom-
mendations for prevention and control.
171,172
https://t.me/medicina_free
11 - Gastrointestinal Disorders and Nutrition |
315
KEY POINT:
Pharmacists in hospitals
and nursing homes may be called on to
aid in antimicrobial stewardship, reduction
in acid-suppressant therapy, selection of
proper therapy, and choosing disinfectants
for use with fomites and the inanimate
environment to reduce the spread of
C. di.
With elderly patients it is most important for the
clinician to have a high index of suspicion for C.
diff. infection when an acute diarrhea occurs,
especially if patients are known to have been
exposed to antibiotics within the past 8 weeks.
However, older, frail patients are more likely to
have severe C. diff. infection and may present
with ileus or toxic megacolon instead of diarrhea.
Enzyme immunoassays for C. diff. enterotoxins
have a sensitivity of 70% to 85% and a specificity
of 95% that does not preclude a negative toxin
test in the presence of a C. diff. infection.
171
Appropriate therapy for elderly patients may
require lower doses of metronidazole, especially
in the face of renal or liver impairment. Long-term
use is associated with irreversible toxicity; there-
fore, patients who have more than one recur-
rence should be treated with alternative agents
instead of repeated courses of metronidazole.
172
Recommended doses of oral vanco-
mycin are 125 mg, although in severe disease
higher doses may be prescribed. Vancomycin
capsules are expensive, so some pharmacies
may compound oral solutions from the intrave-
nous vancomycin powder. Proper techniques
and labeling are required to prevent medication
errors with this practice. For patients with ileus
or toxic megacolon, experts recommend rectal
instillation of vancomycin combined with intrave-
nous metronidazole.
Studies of the efficacy and safety of pro-
biotics for prevention and treatment of C. diff.
infection have conflicting results. Most studies of
lyophilized Saccharomyces boulardii when used
with the initial antibiotic regimen in prevention of
C. diff. infection are favorable. However, the heat-
dried product has stability issues and must be
refrigerated, limiting its likely effectiveness. Use
of S. boulardii as treatment or in recurrent infec-
tion is not supported by good clinical studies.
174
Furthermore, risk for development of fungemia
is higher when this product is used in immuno-
compromised patients, patients in the intensive
care unit, and patients with central venous cath-
eters; therefore, it is not recommended in these
settings.
172
Lactobacillus has some small case
series that support its use, but bacteremia has
been reported. Further study is required before it
can be recommended for routine use.
172
Fecal transplantation has been successful in
curing older adults with recurrent C. diff. infections,
with an 89.6% remission rate. Relapses occurred
with recurrent antibiotic use or in the presence of
the highly virulent NAP1/B1/027 strain.
175
N
Nutritional needs change as a part of normal
aging. Nutritional risk increases dramatically for
this population when these changes are coupled
with an increase in the number and severity of
diseases and their associated therapies. It is
common for older adults to become more seden-
tary and lose lean body mass as they age and
to compensate with a corresponding reduction
in caloric intake. However, because of changes
in micronutrient absorption, disease and drug
effects, and changes in protein breakdown,
malnutrition may develop with a reduction in
intake. The prevalence of undernutrition is high
in older adults, ranging from 14% to 27% in
community-dwelling persons and from 25% to
85% of nursing home residents.
176
Involuntary weight loss may occur if caloric
or protein intake does not meet expenditures.
Inadequate dietary intake may also be a result of
https://t.me/medicina_free
316
| Fundamentals of Geriatric Pharmacotherapy
social factors. Many elderly patients live alone,
and individuals who eat alone tend to eat less
than those who have socialization at mealtimes.
Depressed patients also may eat less. Fixed
incomes may inhibit a retiree from buying food
when money is needed for basic utilities or medi-
cations.
Medical conditions such as dysphagia,
chewing difficulties, paralysis from stroke,
or dementia can prevent individuals from
consuming adequate nutrition. Anorexia is
common with many illnesses, especially
dementia and mood disorders. Medications
may further impair an older adult’s ability to eat
or may reduce appetite. Additional physiologic
changes that occur with aging contribute to
decreased intake, including a reduction in taste
and smell so foods are not as appetizing as they
once were. Older adults have early satiety due
to changes in gastric emptying and changes in
cholecystokinin and leptin release.
177
A second common etiology of involuntary
weight loss in elderly patients is cachexia, a
syndrome of severe weight, fat, and muscle loss
accompanied by elevated protein catabolism
secondary to an underlying disease.
178
Inflam-
mation from diseases such as cancer; obstruc-
tive lung disease; acquired immunodeficiency
syndrome (AIDS); rheumatoid arthritis; and
heart, liver, or renal failure produces cytokines
that cause a dysregulation between catabolism
and anabolism. Anorexia is a common symptom
also associated with the cachexia syndrome.
The loss of muscle mass and strength
that occurs with aging and is responsible for
functional impairment is called sarcopenia. It is
commonly diagnosed by the presence of (1)
muscle mass two or more standard deviations
below normal (adjusted for sex and ethnicity)
in young adults, and (2) diminished walking
speed (below 0.8 miles/sec).
178
Although there
is overlap between cachexia and sarcopenia,
the most common distinguishing feature is that
sarcopenia is not associated with a particular
inflammatory disease. Comorbidities or inad-
equate nutritional intake may be present and
contribute to the development of sarcopenia. It
is currently thought that sarcopenia develops
through a combination of effects from reductions
in testosterone and estrogen, increased insulin
resistance, reduced physical activity, and inad-
equate protein intake.
Overnutrition also occurs in older adults, as
defined by body mass index (BMI) of 25–29.9
(overweight) or >30 (obesity). Obesity is
reported in 37% of men over age 60 and 42%
of women over age 60.
179
Overnutrition is associ-
ated with increased mortality and a number of
diseases in the population as a whole. However,
several studies have shown that overweight
and obesity do not increase mortality in older
adults except perhaps at the highest levels (BMI
above 35). For example, a cohort study of nearly
21,000 community-dwelling Medicare recipients
showed a U-shaped curve for mortality, with
increased mortality above expected in those
with a BMI below 18.5 or above or equal to 35.
No increase in mortality was seen for those with
an overweight BMI or an obese BMI between 30
and 34.9.
180
However, overweight and obesity
were associated with increasing disability.
KEY POINT:
Low body weight
carries a worse prognosis for elderly
patients than overweight or obesity.
For elderly patients who are overweight (BMI
25–29.9) without significant disability, weight
loss is not generally recommended as indi-
viduals in this range do not show an increased
overall mortality. Likewise, weight loss in older
patients with obesity may not influence mortality.
However, weight loss can be an effective means
to reduce cholesterol, blood pressure, blood
glucose, obstructive sleep apnea, and osteo-
arthritic knee pain. When older adults are recom-
mended or choose to lose weight, the strategy
https://t.me/medicina_free
Соседние файлы в папке Библиотека им академика М.И. Перельмана