If it is inert, why does it move?

G. BASSOTTI

Clinica di Gastroenterologia ed Epatologia, Dipartimento di Medicina Clinica e Sperimentale, Universita di Perugia, Italy

Chronic constipation is a frequently experienced

symptom, unfortunately there is no single definition

even among health care workers. Some consensus

documents (such as the Rome II criteria1) provided an

opportunity for such a uniform definition, and these

have been embraced, at least for research purposes.

Three main forms of constipation may be identified:

normal transit constipation, disorders of defecation or

rectal evacuation (outlet obstruction), and slow transit

constipation (STC).2 The latter is usually more severe,

often refractory to medical treatment,3 and probably is

a semantic umbrella under which there are patients

with different severity. Notwithstanding this hetero-

geneity, STC has attracted the interest of researchers,

and its pathophysiological basis has been extensively

explored.4 Several mechanisms of colonic motor dys-

function have been documented.5–7 One form of STC is

called colonic inertia (CI), a subtype that should

constitute the extreme expression of colonic motility

impairment, as the term �inertia� implies. However, it

is unclear what proportion of STC demonstrates iner-

tia.

In this issue, Herve and colleagues investigated a

group of severely constipated patients,8 and conclu-

ded that these subjects represented an heterogeneous

cohort, that CI was present in 25% of cases, and that

bisacodyl may be useful to evaluate whether there is

residual propagated contractile activity that can be

elicited in the colon. These results are already partly

established in the literature on chronically constipa-

ted patients, but the authors� main contribution is

that they attempted to develop objective criteria for

diagnosis of CI, based on manometric measurements.

The proposed criteria are a combination of absence of

high amplitude propagated contractions, lack of

colonic response to eating and an overall reduction

of colonic motility during a 24-h period. The validity

of these recommended criteria requires further study.

For example, delayed colonic transit time was less

frequent in these patients compared with transit

time in the other constipated patients (60% vs 76%).

Moreover, 60% of patients classified as having

CI using these criteria were able to have a

contractile response to the endoluminal infusion of

bisacodyl.

There remains a significant problem in assessing

such studies; there is no agreement in the definition

of CI among authors: definitions may be based only on

the assessment of delayed transit in the right colon,9

in the right and left colon,10 or the term is used as an

equivalent of STC.11 Only rarely have more objective

assessments (including manometric, electromyograph-

ic or scintigraphic investigations) been used12–15

Summarizing these observations in the current study

and in the literature, it appears that most of these

patients should be labelled as STC patients, whose

colons are still able to respond (at least partially) to

pharmacological stimulation. Several years ago, Frex-

inos proposed that true CI should be defined by the

objective absence (or severe impairment) of colonic

motility,16 as demonstrated by manometry and/or

electromyography. It is probably time to embrace this

advice and to develop criteria for true CI, to avoid

further confusion.

For instance, based on the literature, the following

criteria would be reasonable: (i) severe constipation;

(ii) delayed colonic transit (> 2 SD from upper normal

limit); (iii) no evidence of evacuation disorder;

(iv) manometric, electromyographic or scintigraphic

evidence of absent or almost absent colonic motility,

including propagated activity and response to meals;

(v) no response to endoluminal pharmacological sti-

mulation (e.g. bisacodyl) or response to parenteral

neostigmine (1 mg intramuscular).

Such criteria would help identify those patients

whose constipation may be truly refractory to med-

ical treatment or rescue, and in whom surgery is

indicated and it is likely to be of benefit, as the term

will really mean what it says: if it is inert, it does not

move.

Address for correspondence

Dr Gabrio Bassotti, Strada del Cimitero,2/a, 06131 San Marco (Perugia), Italy.Fax: +39-075-584-7570; e-mail: gabassot@tin.it

Neurogastroenterol Motil (2004) 16, 395–396 doi: 10.1111/j.1365-2982.2004.00512.x

� 2004 Blackwell Publishing Ltd 395

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Editorial Neurogastroenterology and Motility