Digital rectal examination and transabdominal ultrasound as diagnostic tools for constipation. Examination of the rectum in children with urology symptoms

Functional constipation in children comprises a variable combination of
gastrointestinal symptoms without signs of an underlying organic etiology. The
pediatric Rome III criteria are useful for clinicians dealing with this
disorder. This symptom-based classification can be used as a diagnostic tool,
but is also used by physicians to explain patients and parents what a
functional diagnosis is. When a patient has at least two out of six Rome III
criteria the diagnosis of functional childhood constipation can be made (see
Tab 1). Additional diagnostic testing is generally not required to establish a
diagnosis (1, 2).

One of the Rome III criteria is the presence of a large fecal mass in the
rectum (1). This can be assessed by performing a digital rectal examination.
It is recommended to do an anorectal examination at least once for a complete
work-up of chronic constipation(1, 2). The examination includes inspection of
the perianal region for perianal feces, fissures, hemorrhoids or malformations.
With digital rectal examination the anal tone, rectum size and possible
abnormalities can be evaluated as well as the amount, consistency and location
of stool within the rectum.(2).

Often children with constipation are referred to pediatric gastroenterologists
without prior perianal inspection or digital rectal examination(3). The lack of
a rectal exam as part of the workup in this setting can be explained by
multiple reasons. For one, physicians can be uncomfortable with the procedure
because of inexperience. Concerns regarding trauma to the child or damaging the
physician-child relationship can be the reason as well. Another consideration
is that the physician assumes that rectal examination is not indicated (3).
Obesity or refusal of the patient can be other child specific reasons to not
perform a rectal exam(1).

Alternative methods are described and applied to assess the degree and location
of stool in the rectum. An abdominal radiograph can be used(1) although several
studies report poor diagnostic accuracy of fecal loading assessment with this
test.(4, 5)

Measurement of the transverse diameter of the rectum with bladder
ultrasonography(US) is used in a few centers, mainly by pediatric surgeons and
urologists, as a parameter for constipation. In 2004 Klijn et.al evaluated
this clinical practice and found a significant larger diameter of the rectum in
patients with dysfunctional voiding and constipation compared to those with a
normal defecation pattern(6). This difference between children with normal and
abnormal bowel habits has been confirmed by others(7-9). Singh et. al found a
significant difference in the median rectal size in children with only
constipation (3.4 cm, range,2.10-7.0) compared to healthy children without
constipation or urology problems (2.4 cm range, 1.3-4.2)(7). The presence of
feces in the rectum and the effect of the fecal mass on the bladder were
evaluated by Lakshminanarayanan et al. They also consider this test to be a
simple and reliable technique to demonstrate fecal loading in children with
constipation (10). So far there is no consensus regarding the possible
correlation between age and the transverse diameter of the rectum(8, 9).
Although multiple studies demonstrated a significant larger rectum diameter
among children with constipation(6-8), only one studied the possible
correlation between a dilated rectum measured by ultrasound and a fecal mass
detected by digital rectal examination(9). An excellent agreement was found
between the findings obtained by digital rectal examination and ultrasound;
i.e. children with a palpable fecal mass exhibited markedly larger rectal
diameters than those without rectal impaction. In this small study
(constipation n=27, healthy controls n=24) all investigations were performed by
the same observer(9).

This study will compare the findings of transverse rectal diameter measured by
transabdominal US to digital rectal examination performed by different
observers. This is relevant because up till now, the performance of a rectal
digital examination is recommended to evaluate the Rome III criteria in
children suspicious for functional constipation. All rectal examinations for
this study will be performed by the research fellow.

Reference List

(1) Rasquin A, Di Lorenzo C, Forbes D, Guiraldes E, Hyams JS, Staiano A, et al.
Childhood functional gastrointestinal disorders: child/adolescent.
Gastroenterology 2006 May;130(5):1527-37.
(2) Constipation Guideline Committee of the North American Society for
Pediatric Gastroenterology HaN. Evaluation and treatment of constipation in
infants and children: recommendations of the North American Society for
Pediatric Gastroenterology, Hepatology and Nutrition. Journal of Pediatric
Gastroenterology & Nutrition 2006 Sep;43(3):e1-13.
(3) Gold DM, Levine J, Weinstein TA, Kessler BH, Pettei MJ. Frequency of
digital rectal examination in children with chronic constipation. Archives of
Pediatrics & Adolescent Medicine 1999 Apr;153(4):377-9.
(4) Bongers ME, Voskuijl WP, van Rijn RR, Benninga MA. The value of the
abdominal radiograph in children with functional gastrointestinal disorders.
Eur J Radiol 2006 Jul;59(1):8-13.
(5) Reuchlin-Vroklage LM, Bierma-Zeinstra S, Benninga MA, Berger MY. Diagnostic
value of abdominal radiography in constipated children: a systematic review.
Archives of Pediatrics & Adolescent Medicine 2005 Jul;159(7):671-8.
(6) Klijn AJ, Asselman M, Vijverberg MA, Dik P, de Jong TP. The diameter of the
rectum on ultrasonography as a diagnostic tool for constipation in children
with dysfunctional voiding. J Urol 2004 Nov;172(5 Pt 1):1986-8.
(7) Singh SJ, Gibbons NJ, Vincent MV, Sithole J, Nwokoma NJ, Alagarswami KV.
Use of pelvic ultrasound in the diagnosis of megarectum in children with
constipation. Journal of Pediatric Surgery 2005 Dec;40(12):1941-4.
(8) Bijos A, Czerwionka-Szaflarska M, Mazur A, Romanczuk W. The usefulness of
ultrasound examination of the bowel as a method of assessment of functional
chronic constipation in children. Pediatr Radiol 2007 Dec;37(12):1247-52.
(9) Joensson IM, Siggaard C, Rittig S, Hagstroem S, Djurhuus JC. Transabdominal
ultrasound of rectum as a diagnostic tool in childhood constipation. J Urol
2008 May;179(5):1997-2002.
(10) Lakshminarayanan B, Kufeji D, Clayden G. A new ultrasound scoring system
for assessing the severity of constipation in children. Pediatr Surg Int 2008
Dec;24(12):1379-84.

Primary: To investigate if there is a correlation between findings of
transabdominal ultrasound measurement of the rectum and rectal digital
examination.
Secondary: To investigate if there is a correlation between an enlarged rectum
(diameter > 30 mm) and fulfillment of the pediatric Rome III criteria for
functional constipation.

This is a prospective open study. Participants will be patients already
scheduled for a urology procedure in the operation room (OR). Transabdominal
ultrasound (US) is routinely performed in all patients in the OR.
Transabdominal US is performed to evaluate bladder filling and the diameter of
the rectum before starting the procedure. A Paracetamol suppository is given to
all patients for pain relief; rectal digital examination is done during
placement. In the recovery area parents will be asked about the bowel habits of
their child.
Ultrasound
Transabdominal measurement of the rectal diameter is performed with the patient
in supine position as described by Klijn et al. A 7.5 MHz sector probe is
applied to the abdomen approximately 2 cm above the symphysis at a 10 to
15-degree downward angle. The diameter of the rectum is measured in the
transverse plane. At each session the diameter is measured two times and a mean
value will be calculated. Measurement can be performed with a moderately (30%
to 70% of capacity for age) filled bladder (Klijn 2004).
Anorectal examination
Anorectal examination of the anorectal region encloses inspection and digital
rectal examination. During inspection of the perianal region the presence or
absence of perianal feces, anal fissures or hemorrhoids will be assessed.
During digital examination the amount and consistency of stool will be assessed
and presence or absence a rectal scybalus evaluated. This exam will be done by
another person blinded for the findings of the Ultrasound. All anorectal
examinations for this study will be performed by the research fellow.
Test results will be reported on a form which is designed for this study. These
forms will be placed in the patient chart before they go to the OR.
Screening:
In the recovery room questions will be asked to the parents regarding the bowel
habits of their child (defecation frequency, painful and/or hard stools, fecal
incontinence, stool withholding behavior, large amounts of stools). Also
questions about the patients medical history (abnormalities/malformations or
previous surgery in the anorectal/pelvic region) will be asked.

There is no additional risk for participating subjects in this study since the
digital rectal examination is a safe and non-invasive test. There is no
additional cost to participate in this study. Participation in this study has
no directs benefits for the study subjects. Study subjects will not be paid to
be in this study.