Mistakes in ... Booklet 2020 - 8

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Stage

Description

0

Mild clinical diverticulitis
(no clear signs on imaging)

Ia

Confined pericolic inflammation
or phlegmon

Ib

Pericolic or mesocolic abscess

II

Pelvic, distant intra-abdominal or
retroperitoneal abscess

III

Generalized purulent peritonitis

IV

Generalized faecal peritonitis

Table 1 | Modified Hinchey classification of acute
diverticulitis.4

cohort study, included 86 patients with uncomplicated diverticulitis who received
an unrestricted diet; about 8% were readmitted
for pain management but without developing
complicated diverticulitis.6 These results are
in line with what has been reported as the
complication rate in patients with an episode of
initially uncomplicated diverticulitis.8
Although a high-fibre diet may be
recommended for general health purposes,
there is little evidence that it benefits recovery
during acute diverticulitis episodes or
prevents recurrent episodes. The quality of this
evidence is low, but in the absence of evidence
favouring dietary restriction, we believe that an
unrestricted diet is justifiable for patients who
have acute (uncomplicated) diverticulitis. Also,
the negative effects of malnutrition need to be
avoided, since it can prolong hospital stay for
patients who are admitted.

Mistake 3 Thinking all large abscesses must
be treated by (emergency) surgery
Treatment of abdominal abscesses caused by
acute diverticulitis (figure 2) has changed
considerably over the years. Patients can now be
treated conservatively with antibiotics, undergo
percutaneous drainage, receive a combination of
antibiotics and percutaneous drainage, or undergo
(emergency) surgery.
With the improvement of CT imaging and CTor US-guided interventions, percutaneous
drainage has become a frequently performed
procedure for patients with diverticular abscesses.
A systematic review with meta-analysis from 2016
included 42 articles and focused on patients
with diverticular abscesses who were treated
nonoperatively (either with antibiotics or
percutaneous drainage).9 The primary outcome
of the systematic review was therapy failure,
defined as emergency surgery, readmission or
32

Mistakes in... 2019

mortality within 30 days of initial treatment,
residual abscess at follow-up or persistent
symptoms. The results showed a pooled failure
rate of approximately 20%.
Since then, a multicentre retrospective cohort
study has been published that focused on the
outcome of nonsurgical treatment for patients
with a CT-diagnosed diverticular abscess
(modified Hinchey Ib or II; table 1).10 Treatment
with antibiotics only was compared with
treatment with a combination of antibiotics and
percutaneous drainage-no difference in short-term
treatment failure, the need for emergency surgery
or long-term surgery was found between the
two groups. Treatment failure in this study
was defined as a composite outcome of
complications (perforation, colonic obstruction
and fistula formation), readmissions, persistent
diverticulitis, emergency surgery, death, or need
for percutaneous drainage in the no percutaneous
drainage group. Short-term treatment failure in
Hinchey Ib patients was 22.3% for antibiotic
treatment only versus 33.0% in patients who
received antibiotics plus additional percutaneous
drainage (P = 0.359). Results for Hinchey II patients
were similar, with a short-term failure of 25.9% for
patients receiving antibiotics only versus 36.0% for
patients receiving antibiotics with additional
percutaneous drainage (P = 0.149).10 Abscesses
>5 cm in diameter were associated with the need
for surgery at short-term follow-up (P = 0.036).
In our opinion, the size and location of an
abscess, and whether or not it has an enhancing
wall, determines the therapy of choice and the
possibility of performing percutaneous drainage. For
patients who have an abscess <3cm, treatment with
antibiotics only is appropriate. Although the role of
percutaneous drainage of abscesses in acute diverticulitis is not completely clear, we think it may be
considered in patients who have an abscess
>3 cm. In case of failure of percutenous drainage
and/or antibiotics, and in a critically ill or
deteriorating patient (emergency), repeating

a

Diverticulum

abdominal CT followed by emergency surgery
may be necessary.

Mistake 4 Overlooking the need for the
appropriate imaging evaluation
Since the treatment of acute diverticulitis has
changed dramatically over the years, the role of
imaging diagnostics has become more important.
US and CT are now widely available and frequently
used in the emergency department to aid the rapid
and correct diagnosis of acute diverticulitis and to
determine its severity.
Classifying a patient correctly and without
delay as having uncomplicated or complicated
diverticulitis is essential because it influences
treatment choice; in most cases, acute
uncomplicated diverticulitis can be treated
conservatively. Although a US diagnosis of
acute diverticulitis is reliable, US is less accurate
than CT for distinguishing uncomplicated from
complicated diverticulitis (figure 3).11 Missing
complicated diverticulitis can have severe clinical
implications. Therefore, especially in clinically
ill patients who have failure of one or more
organs other than the digestive tract, we advise
performing an abdominal CT to confirm
the diagnosis and to confirm or exclude
complications. In suspected uncomplicated
diverticulitis, starting with US is advised.10
Moreover, CT has a higher diagnostic accuracy
compared with US for detecting an alternative
diagnosis, which could obviously influence
treatment choice.12,13

Mistake 5 Assuming pericolic extraluminal
air in left-sided acute colonic diverticulitis
must be treated with emergency surgery
Pericolic extraluminal air is seen on a CT scan in
about 15% of patients with acute diverticulitis
and is often wrongly associated with the need for
emergency surgical intervention.14,15 The Hinchey

b

Abscess

Perforation
Inflammatory
adhesions
Figure 2 | Acute diverticulitis. a | Uncomplicated diverticulitis with peridiverticular inflammation of the colon.
b| Inflammatory adhesions, abscess formation and perforation indicate the presence of complicated
diverticulitis, as do obstruction and fistula formation.
Mistakes in ... Booklet 2020

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