(1)
Incidence
Diverticular disease
and its associated complications have increased over this century.
While the incidence of diverticular disease increases with age, of
importance to the GMO is that 2-6 percent of patients with
diverticular disease are younger than 40 and include a preponderance
of men.
(2)
Definition and
terminology
A diverticulum is an
abnormal pouch or sack consisting of mucosal and submucosa opening
from a hollow viscus. Colonic diverticula are false diverticula that
protrude through the colonic musculature alongside any of the three
taenia. Diverticula are noted to protrude through the musculature at
sites created by the small arteries that supply blood to the mucosa
(vasa recta).
·
The presence of protrusions
of mucosa through the muscular wall of the colon is termed “diverticulosis”.
When inflammation is superimposed the term “diverticulitis” is used.
The term “diverticular disease” is used to describe the entire
spectrum of clinical consequences of the presence of diverticula of
the colon.
(3)
Pathogenesis
The exact
pathogenesis of diverticulosis is unknown and probably
multi-factorial. There are different patterns of disease related to
changes in colonic wall connective tissue and increased intraluminal
pressure. Certain people will have a predisposition to colonic wall
weakness and when associated with altered colonic motility and
increased intraluminal pressure the result is mucosal protrusions
through colonic wall defects, creating diverticula.
(4)
Natural History
Despite the
prevalence of diverticulosis of the colon within the population, the
majority of those with diverticulosis remain symptom free. It is
estimated that as many as 30-40 percent of patients with
diverticulosis develop symptoms related to the diverticula over a
lifetime. Patients with diverticular disease may develop
diverticulitis, fistulas, obstruction, or hemorrhage. In one large
study of asymptomatic patients over 15 years, clinical diverticulitis
developed in 25 percent, obstruction in 5 percent, clinical
perforation in 5 percent, and significant hemorrhage in 5 percent.
Approximately 30 percent of patients with symptomatic diveticular
disease will eventually require surgical intervention.
(a)
In terms of duration of
symptoms, half of those with symptomatic diverticular disease were
free of symptoms up to 1 month before presentation. Three quarters
have symptoms for less than 1 year. Patients who present with serious
complications may be asymptomatic until hours before admission.
(b)
In terms of recurrence after
an initial episode of diverticulitis, one-third to two-thirds of
patients will have recurrent attacks or continue to have symptoms.
About one-fourth will require hospitalization for recurrent episodes.
Approximately half of those requiring admission for a second attack
will do so within 1 year of the first attack, and 90 percent are
admitted within 5 years. Medical management of recurrent attacks is
less effective than treatment of the presenting attack. The
complication rate increases with subsequent attacks, being 23 percent
for one attack and 58 percent for more than one attack.
(c)
As far as younger patients
are concerned (<40), their initial attack of diverticulitis tends to
be more severe than their older counterparts and a significant number
will require surgical intervention for the complications of
diverticulitis during the initial hospitalization. However, follow up
data varies as to incidence and severity of recurrent disease or
complications between different studies.
(d)
Repeated attacks of
diverticulitis increase the risk of a complication from diverticular
disease. Complicated diverticular disease requiring emergent surgery
is associated with increased morbidity and mortality compared to
elective colon resection. Thus, in good risk patients who have
required hospitalization for repeated attacks of diverticulitis,
elective resection is recommended.
(5)
Acute Diverticulitis:
Pathogenesis
Inspissated stool or
a fecalith within a thin walled diverticulum will cause erosion and
inflammation leading to infection and perforation. This may vary from
a minimal peridiverticular phlegmon, which progresses to a
peridiverticular or mesenteric abscess, which may then become a walled
off pelvic or intra-abdominal abscess, to one that perforates into the
free peritoneal cavity causing generalized peritonitis. Usually only
one diverticulum becomes inflamed leading to the different stages of
inflammation noted.
(6)
Differential
Diagnosis
Depending on the
presenting symptoms, other entities should be considered in the
differential diagnosis. This would include Crohn’s disease, ulcerative
colitis, appendicitis, Meckel’s diverticulitis, penetrating ulcer,
ureteral colic, urosepsis, pelvic inflammatory disease (PID),
tubo-ovarian abscess (TOA), ovarian torsion, endometriosis, and small
bowel obstruction. In older individuals include ischemic colitis,
volvulous, and most importantly carcinoma. Rectal bleeding is
distinctly uncommon in diverticulitis and should make one consider a
different diagnosis.
(7)
Peridiverticular Inflammation /
Phlegmon
This is the most
common form of diverticulitis. Patients present with acute, steady,
left lower abdominal discomfort. This may be associated with
alteration in bowel habits with either constipation or diarrhea. There
may be a low-grade fever but the patient is not tachycardic.
Examination reveals mild left lower quadrant tenderness without an
appreciable mass.
Treatment can be
carried out on an outpatient basis and consists of clear liquids by
mouth and a broad-spectrum oral antibiotic for 7-10 days.
Trimethoprim-sulfamethoxazole, 1 tab BID, and metronidazole, 250mg QID,
or ciprofloxacin, 500mg BID, and metronidazole are good combinations
to use. Solid foods may be started as symptoms subside and a high
fiber diet instituted after resolution of the inflammation. Follow-up
evaluation should include flexible sigmoidoscopy and barium enema
after the inflammation has resolved, usually at 3-4 weeks.
(8)
Pericolic or Mesenteric Abscess
The patient with
this stage of inflammation will complain of moderate to severe left
lower abdominal pain and anorexia. Alteration in normal bowel habits
with constipation or diarrhea will occur. Abdominal exam reveals a
tender mass and voluntary guarding in the lower abdomen. Rebound
tenderness or referred rebound tenderness may be present. Pyrexia and
tachycardia are usually present.
(a)
A chest x-ray along with flat and upright
abdominal films can assist with excluding the presence of free
intraperitoneal air or intestinal obstruction. Urinalysis can exclude
urinary tract infection, fecaluria, and ureterolithiasis. Leukocytosis
is usually present.
(b)
The patient is best treated with
hospitalization, bowel rest, IV hydration, and IV antibiotics.
Antibiotics should cover both aerobes and anaerobes. Cefoxitin or
Unasyn are good single agents to start with. If patients appear more
toxic, then an aminoglycoside with metronidazole and ampicillin for
enterococcus coverage may be used. Imipenem or Trovan may be used as a
single agent in this situation. Nasogastric suction is unnecessary
except for persistent emesis or obstruction. A water-soluble contrast
enema or CT scan is useful to confirm the diagnosis in atypical
presentations or if not improving within 48 hours.
(c)
Again, most of these patients will resolve
on medical management and should undergo further evaluation after
resolution of the inflammation.
(9)
Generalized Purulent or Feculent
Peritonitis
When the inflamed
colon or abscess freely perforates into the peritoneal cavity
generalized peritonitis and the true “acute abdomen” will occur.
Patients will complain of severe diffuse abdominal pain with anorexia,
nausea and vomiting. The patient is tachycardic, pyrexic, and
dehydrated. Severe tachycardia and hypotension are signs of septic
shock. On examination, the patient will have a diffusely tender
abdomen with involuntary guarding, rebound and percussion tenderness,
and absent or rare bowel sounds. An upright CXR and acute abdominal
series may reveal free intraperitoneal air. The first step in
management of peritonitis is volume replacement with IV fluids (NS or
LR). Treatment also includes insertion of an NG tube, Foley catheter,
and administration of IV antibiotics. Surgical exploration should
follow immediately. Surgical treatment involves resection of the
involved colon, abdominal irrigation, drainage of any abscess and
formation of a colostomy. Post-operative complications of ARDS, stress
ulcers, ongoing sepsis, and possible multi-organ system failure make
early recognition and rapid resuscitation and treatment of this entity
essential in decreasing its morbidity and mortality.
(10)
Diverticular Hemorrhage
Diverticular
bleeding occurs in 5-15 percent of patients with diverticulosis. The
average age is 65 years. Diverticular hemorrhage is usually massive
but self-limited. Bleeding stops spontaneously with supportive
management in 70 – 95 percent of cases. Recurrent episodes occur in 25
percent of patients. After a second hemorrhage, the chance of a third
increases to 50%.
Classic bleeding in
diverticulosis is painless and associated with the sudden passage of a
large amount of bright red or maroon-colored stool. Orthostatic
symptoms may ensue. Mild cramping abdominal pain is due to the
cathartic effect of the intracolonic blood. Similar type bleeding may
arise from other sources such as angiodysplasias, vascular
malformations, Meckel’s diverticulum, or rarely, carcinoma. Associated
symptoms of recent diarrhea suggest inflammatory bowel disease or
infectious etiology.
Patients with
massive lower GI bleeding need to be approached similar to those with
UGI hemorrhage. Institute IV fluid resuscitation immediately while
initially assessing patient. Document patient’s vital signs and
hemodynamic stability. Draw blood for type and cross, CBC,
electrolytes, liver functions, and coagulation profile. Document
duration and amount of bleeding, presence of melena, or prior history
of bleeding. A history of medication use to include ASA, NSAIDS,
coumadin, or alcohol abuse, or a history of liver or renal disease may
predispose the patient to rectal bleeding. Abdominal exam is usually
unremarkable. Digital anal exam reveals gross evidence of rectal
bleeding. Anoscopy and proctoscopy should be performed to eliminate
an anorectal source of bleeding. A nasogastric (NG) tube is placed to
exclude an upper GI source. If the NG aspirate does not contain bile
an upper source cannot be excluded, but is less likely. If the
aspirate contains evidence of bleeding an upper GI source is most
likely and an urgent esophageal gastroduodenoscopy (EGD) will be
required. All patients with an acute major GI bleed must be
transferred to an MTF as soon as possible.
Reference
(a)
Gordon, Philip H.: Diverticular Disease of
the Colon. In: Principles and Practice of Surgery for the Colon,
Rectum, and Anus, 2nd Edition. St.Louis: QMP. 1999:
975-1037.
Submitted by
CAPT H.R. Bohman, MC, USN, General Surgery Specialty Leader, Naval
Hospital Camp Pendleton, CA (1999).
|