This can happen to both d and c IBSers.
But
"Sometimes people experience a sensation of incomplete evacuation, even when the rectum is empty."
IN D IBS you may have d and urgency at first followed by the sensation of incomplete evacuation.
In IBS the rectum can send abnormal signals to the brain. The nerves in the rectum can be hypersensitive so an extremely small amount of pressure can send a signal to the brain of the "Sensation of incomplete evacuation."
with consitpation the pelvic muscles may need to be checked out as well for pelvic floor disorders, that may lead to the feeling of incomplete evacuation.
"What is pelvic floor dyssynergia?
Pelvic floor dyssynergia is the underlying etiology for 25% of cases of primary constipationVIEW IMAGE. Although it is considered a disorder of the rectum and anus, these patients also have abnormal contractions throughout the colon. Dinning and colleagues recently showed that patients with pelvic floor dyssynergia had abnormal colonic pressure waves prior to defecation. Patients with pelvic floor dyssynergia present with symptoms that may include a sensation of incomplete evacuation, excessive straining, a need for digital disimpaction, perianal heaviness, and tenesmus. Soft stools and even enema fluid may be difficult to pass."
http://www.emedmag.c...ults/041505.asp
Functional constipation is the presence of two or more of the following:
Straining during at least 25% of bowel movements,
Lumpy or hard stools in at least 25% of bowel movements,
Sensation of incomplete evacuation for at least 25% of bowel movements,
Sensation of anorectal obstruction or blockage for 25% of bowel movements,
Manual maneuvers to facilitate at least 25% of bowel movements and/or,
Infrequent (fewer than 3) bowel movements per week.
http://www.aboutconstipation.org/
Its worth reading this page
http://www.aboutconstipation.org/site/abou...haracteristics/
There is a lot in the IBS and consitpation literature on the "sensation of incomplete evacuation." which is in part a neurologic process. Basically the neves in the rectum are hypersensitive and even when there is almost no matter in the rectum there after going, it can still sends a signal to the brain 'sensory feedback' there is still stuff there. That's put really simply however.
This is more complex on it all
Neurophysiological evaluation of healthy human anorectal sensation
http://ajpgi.physiol...full/291/5/G950
There are other issues with IE however to consider.
FYI
First Principles of Gastroenterology
3.6.3 PELVIC FLOOR DYSSYNERGIA
The majority of patients with constipation have a form of irritable bowel syndrome, but there is a small subgroup of patients who may have a specific disorder in colonic and/or anorectal function that produces constipation. These patients are almost all female, may have delayed colonic transit or present with anorectal dysfunction with impaired awareness to rectal distention (without a megarectum), or may demonstrate a phenomenon of rectal outlet obstruction due to inappropriate contraction of the voluntary anal sphincters during defecation. This has been termed pelvic floor dyssynergia or anismus. These patients can present major therapeutic dilemmas and warrant further investigation in specialized coloproctology units involved in the care of such patients.
http://gastroresourc...ok/en/index.htm
"specialized coloproctology unit" can test
"The nervous system that controls the gastrointestinal organs, as with most other organs, contains both sensory and motor nerves. The sensory nerves continuously sense what is happening within the organ and relay this information to nerves in the organ's wall. From there, information can be relayed to the spinal cord and brain. The information is received and processed in the organ's wall, the spinal cord, or the brain. Then, based on this sensory input and the way the input is processed, commands (responses) are sent to the organ over the motor nerves. Two of the most common motor responses in the intestine are contraction or relaxation of the muscle of the organ and secretion of fluid and/or mucus into the organ.
As already mentioned, abnormal function of the nerves of the gastrointestinal organs, at least theoretically, might occur in the organ, spinal cord, or brain. Moreover, the abnormalities might occur in the sensory nerves, the motor nerves, or at processing centers in the intestine, spinal cord, or brain. Some researchers argue that the cause of functional diseases is abnormalities in the function of the sensory nerves. For example, normal activities, such as stretching of the small intestine by food, may give rise to abnormal sensory signals that are sent to the spinal cord and brain, where they are perceived as pain.
Other researchers argue that the cause of functional diseases is abnormalities in the function of the motor nerves. For example, abnormal commands through the motor nerves might produce a painful spasm (contraction) of the muscles. Still others argue that abnormally functioning processing centers are responsible for functional diseases because they misinterpret normal sensations or send abnormal commands to the organ. In fact, some functional diseases may be due to sensory dysfunction, motor dysfunction, or both sensory and motor dysfunction. Still others may be due to abnormalities within the processing centers."
http://www.medicineonline.com/encyclopedia...-Bowel-Syndrome
Management of Bladder, Prostatic and Pelvic Floor Disorders with
Botulinum Neurotoxin
Current Medicinal Chemistry, 2005, 12, 247-265
"CONSTIPATION DUE TO PELVIC FLOOR
DYSFUNCTION
Pelvic floor dysfunction is characterized by a failure of the puborectalis muscle to relax during efforts to defecate, or by its paradoxical contraction. With an effort to evacuate the rectum, the puborectalis and the EAS normally relax to straighten the anorectal angle and open the anal canal. The diagnosis is suggested by the demonstration of a persistent impression of the puborectalis on the posterior surface of the anal canal during attempted evacuation of barium paste and, more reliably, by EMG evidence of increased electrical activity in the puborectalis muscle during straining.
"Pelvic floor dissynergia Failure of coordinated relaxation of the striated muscles (puborectalis muscles, external anal sphincter) during attempted expulsion of rectal contents. Studies suggests that this is a learned but unconscious act that often can be corrected by biofeedback techniques."
New discussion on rome 111 and Functional Anorectal Disorders.
F3a. Diagnostic Criteria for Dyssynergic
Defecation Inappropriate contraction of the pelvic flooror less than 20% relaxation of basal resting
sphincter pressure with adequate propulsive forces during attempted defecationF3b. Diagnostic Criteria for Inadequate Defecatory PropulsionInadequate propulsive forces with or with-out inappropriate contraction or less than 20% relaxation of the anal sphincter during attempted
defecation
"Physiologic and Psychological FactorsFunctional defecation disorders are probably ac-quired behavioral disorders because at least two thirds of patients learn to relax the external anal sphincter and puborectalis muscles appropriately when provided with biofeedback training. It has been peculated that pain associated with repeated attempts to defecate large, hard stools may lead to inadvertent anal sphincter contraction, to minimize discomfort during defecation. However, rectal discomfort is not more common in pelvic floor dysfunction compared to normal or slow-transit consti-
pation.57Anxiety and/or psychological stress may also contribute to dyssynergic defecation by increasing skel-etal muscle tension. Uncontrolled studies have reported sexual abuse in 22% of women with functional defecation disorders, and 40% of women with functional lower
gut disorders, including functional defecation disorders.39,58 Treatment Functional defecation disorders are managed bypelvic floor training using (1) biofeedback techniques in which patients receive feedback on striated muscle activity recorded by anal or perianal EMG or pressure sen-
sors59 – 62; or (2) simulated defecation in which the patient practices evacuating an artificial stool surrogate,perhaps combined with diaphragmatic muscle training.62 Controlled and uncontrolled studies suggest anoverall success rate of 67% to 80% after pelvic floor retraining for functional defecation disorders."
http://216.109.125.130/search/cache?ei=UTF...=1&.intl=us
You said stress makes it worse.
"psychological stress may also contribute to dyssynergic defecation by increasing skeletal muscle tension."
Biofeedback therapy for dyssynergic defecation
Giuseppe Chiarioni, Steve Heymen, William E Whitehead
"Abstract
Dyssynergic defecation is one of the most common forms of functional constipation both in children and adults; it is defined by incomplete evacuation of fecal material from the rectum due to paradoxical contraction or failure to relax pelvic floor muscles when straining to defecate. This is believed to be a behavioral disorder because there are no associated morphological or neurological abnormalities, and consequently biofeedback training has been recommended for treatment. Biofeedback involves the use of pressure measurements or averaged electromyographic activity within the anal canal to teach patients how to relax pelvic floor muscles when straining to defecate. This is often combined with teaching the patient more appropriate techniques for straining (increasing intra-abdominal pressure) and having the patient practice defecating a water filled balloon. In adults, randomized controlled trials show that this form of biofeedback is more effective than laxatives, general muscle relaxation exercises (described as sham biofeedback), and drugs to relax skeletal muscles. Moreover, its effectiveness is specific to patients who have dyssynergic defecation and not slow transit constipation. However, in children, no clear superiority for biofeedback compared to laxatives has been demonstrated. Based on three randomized controlled studies in the last two years, biofeedback appears to be the preferred treatment for dyssynergic defecation in adults.
"Diagnostic criteria for functional defecation disorders[4] include those for functional constipation[5], namely two or more of 6 symptoms present for the last 3 mo with an onset more than 6 mo in the past; the symptoms are straining, lumpy or hard stools, sensation of incomplete evacuation, sensation of anorectal obstruction/blockage, or manual maneuvers to facilitate defecation on more than 1/4 of bowel movements, or less than 3 bowel movements per week. To meet criteria for functional defecation disorders, the patient must also undergo objective diagnostic testing and demonstrate at least two of three abnormalities: impaired evacuation of the rectum, inappropriate contraction or less than 20% relaxation of the pelvic floor muscles, and inadequate propulsive forces during defecation[4]. "
http://www.wjgnet.co...327/12/7069.asp
From our improved appreciation of the role of the pelvic floor and anal sphincter muscles in the process of evacuation (Figure 2) and of disturbances in the dynamics of defecation,[10] it is clear that pelvic floor disorders may produce a syndrome virtually identical to the so-called constipation-predominant IBS. Therefore, a history of excessive straining, a sense of incomplete evacuation, or the need to digitate the rectum or vagina to facilitate emptying of the rectum are all features associated with pelvic floor or anal sphincter dysfunction.[8,10,25] In patients with constipation, it is essential to perform a careful rectal examination that includes assessments of the anal sphincter tone at rest, the ability of the puborectalis to relax during straining,[10] and the descent of the perineum during straining.[25] Simple screening tests, such as the balloon expulsion test and measurement of perineal descent, are available to confirm the clinical diagnosis.
Figure 2. (click image to zoom) Pelvic floor and anal sphincter functions involved in continence and defecation. Continence requires: contraction of puborectalis, maintenance of anorectal angle, normal rectal sensation, and contraction of sphincter. Defecation requires: relaxation of puborectalis, straightening of anorectal angle, and relaxation of sphincter. Reprinted with permission from Camilleri et al.[8]
The differentiation between evacuation disorders and IBS-constipation has important practical implications. For example, a prokinetic agent for constipation is unlikely to work in patients with evacuation disorders. Much direct and indirect expenditure attributable to IBS might be avoided then if more attention were placed on the rectal examination of these patients.
Colonic and rectal hypersensitivity are very relevant in IBS patients with diarrhea and urgency.[26-28] Hypersensitivity has been proposed as a biologic marker of the condition[28]; however, the lack of responsiveness of rectal hypersensitivity in clinical trials[29] and its poor correlation with clinical responses challenge whether this symptom can be used as a biologic marker.[30] Anxiety, psychosensory function, and limbic system activation may contribute to the increased rectocolonic sensitivity.[31-33] In summary, the evidence for hypersensitivity in IBS is considerable, but the proof of its clinical relevance will depend on the development of effective therapies and documentation of clinical benefit by restoring normal sensation.[34]"
http://www.medscape....rticle/407938_4
Its been esimated some 80% percent of IBSers have rectal hypersensitivity.