Mistakes in ... 2021 - 23

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Mistakes in... 2021
Clinical history variable
First occurance of disease
Stool consistency
Stool frequency
Nocturnal diarrhoea
Irritable bowel syndrome
Usually before 50 years of age
Soft, variable or hard
Can vary from day to day
Very unlikely
Feeling of incomplete bowel evacuation Common
Feeling of fullness/bloating
Accompanying autoimmune disease
Common
Rare
Microscopic colitis
Usually after 50 years of age
Watery/soft
High and more consistent
Possible
No
Rare
Common
Table 1 | Differences in clinical history between patients with irritable bowel syndrome and those with
microscopic colitis.
disease and even with normal controls.
In one study from Wildt et al., 50% of patients
with active microscopic colitis had a calprotectin
level below 100 mg/kg, and this level is used as
the cut-off for colonoscopy referral in some
countries.6
Reliance on this cut-off should
therefore be avoided to prevent patients with
microscopic colitis missing out on a diagnosis.
Calprotectin is mainly released by neutrophils
and these white blood cells are not involved
in microscopic colitis to a great extent, which
explains why faecal calprotectin levels might
not reflect the degree of inflammation in these
patients.
Mistake 4 Thinking that stool frequency is
more important than consistency
The classic definition of chronic diarrhoea is
≥3 defecations/day for a duration of ≥4 weeks.7
Although stool frequency is easy to assess, it might
not be the factor that has the greatest impact on a
patient's quality of life. The major symptom
of microscopic colitis is watery diarrhoea, so
defining diarrhoea in terms of stool consistency
could have theoretical advantages. This is because
stool form correlates better with other symptoms
of microscopic colitis, like urgency and faecal
incontinence, which are likely to have a bigger
impact on a patient's quality of life.
In one cross-sectional study, the aim was to
evaluate the influence of bowel symptoms on
the subjective experience of quality of life of
patients with microscopic colitis and to suggest
definitions for clinical activity. The results of this
study are the Hjortswang criteria,8
which define
clinical remission as a mean of <3 stools/day and
a mean of <1 watery stool/day over a week of
symptom registration, and clinical activity to be
Stools per day
Clinical remission
Clinical activity
<3
≥3
And
Or
a mean of ≥3 stools/day or a mean of ≥1 watery
stool/day over a week (table 2). New with
these criteria is the understanding that stool
consistency might influence a patient's quality
of life more negatively than stool frequency and
therefore that it is justifiable to treat patients who
have just one watery stool daily.
Mistake 5 Failing to offer regular
follow-ups to patients with microscopic
colitis
According to some retrospective cohort
studies, you could get the impression that most
patients with microscopic colitis are in a state
of long-lasting clinical remission so regular
follow-ups are unnecessary. However, these
studies often have major limitations and use
varying criteria to assess disease course.
A more recent, prospective, one-year
observation of patients in the EMCG registry
(the PRO-MC collaboration) has shown that
only a minority of patients with microscopic
colitis follow a quiescent disease course with
spontaneous clinical improvement. The majority
suffer a chronic active or relapsing disease
course during the first year after diagnosis,
with persisting symptoms accompanied by a
significantly impaired quality of life.9
In my experience, many patients are reluctant
or embarrassed to talk about their bowel habits
and do not seek help. It can be quite astonishing
to discover how patients with microscopic colitis
have adapted to live with their symptoms or live
in a state of isolation and neglect. As doctors, we
have to address these problems, inform patients
about the clinical activity criteria for microscopic
colitis as given in table 2 and encourage them to
make contact if they have symptoms, whilst noting
Watery stools per day
<1
≥1
Table 2 | The mean average number of stools or watery stools per day according to clinical remission or activity
during one week of symptom registration.
that the endoscopic and histological follow-ups or
screening programs that are used for colon cancer
are not recommended.1
Mistake 6 Believing that microscopic
colitis is mainly drug induced
My impression is that there is a widespread
opinion that microscopic colitis is often drug
induced and some believe there is even
causality. Many drugs have been suspected to
induce microscopic colitis, but only the chronic
or frequent use of proton pump inhibitors (PPIs),
nonsteroidal anti-inflammatory drugs (NSAIDs)
or selective serotonin reuptake inhibitors
(SSRIs) is associated with an increased risk of
microscopic colitis.1
However, this association
does not imply a causal relationship. The data
derive mainly from retrospective case-control
studies and different criteria for 'drug exposure'
were applied or different reference populations
were considered.1
Moreover, the studies
lack information on the evolution of clinical
symptoms after drug exposure, withdrawal or
rechallenge, which hinders the assessment of
causality. It is therefore more reasonable to
claim that these drugs are merely triggers of
inflammation in predisposed individuals.
The EMCG suggests considering the
withdrawal of any drugs for which there is a
suspected chronological relationship between
drug introduction and the onset of diarrhoea,
especially in those cases where a patient has been
continuously exposed to a drug for 4-12 months.1
Symptoms should resolve within 1-2 weeks of
drug withdrawal. To rechallenge a patient with
the same drug to establish causality is often not
feasible in clinical practice but, in 10 different
cases, switching to another PPI did not result in
the recurrence of diarrhoea, which contradicts the
presumption of a class effect for PPIs.1
Mistake 7 Neglecting patients with
incomplete microscopic colitis
Incomplete microscopic colitis is a new term that
is used to describe patients who have chronic,
watery diarrhoea and histological findings that
are not normal, but who fall short of fulfilling
the classic criteria for microscopic colitis.10
Patients should have active disease according
to the Hjortswang criteria8
and an established
histological diagnosis of incomplete
microscopic colitis defined as: an increased
lymphoplasmacellular infiltrate in the
lamina propria; a thickened subepithelial
collagenous band, >5 μm and <10 μm; and/or
abnormal intraepithelial lymphocytes, >5
and <20 per 100 epithelial cells. To date,
incomplete microscopic colitis is not yet
established globally and has previously gone
under many different names (e.g. paucicellular
microscopic colitis).
11
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