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1 Chronic Constipation and Obstructed Defecation: Definition, Diagnosis and Clinical Approach

Chronic constipation is a worldwide problem increasing with age. It can be either primary or secondary. It is often, erroneously, considered as a single disease but it is a complex and multifaceted syndrome. There are many different causes able to induce secondary constipation (Tables 24.1 and 24.2).

Table 24.1 Medications more commonly related to constipation
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Table 24.2 Condition associated to constipation (Diamant et al. 1999)
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The term “primary constipation” itself hides different conditions, such as irritable bowel syndrome with constipation (IBS-C), functional constipation, functional defecation disorders, and rectal hyposensitivity (Bellini et al. 2015; Bharucha et al. 2006; Longstreth et al. 2006) (Tables 24.3 and 24.4).

Table 24.3 Rome III criteria for differential diagnosis between functional constipation and irritable bowel syndrome (Bharucha et al. 2006)
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Table 24.4 Roma III diagnostic criteria for functional defecation disorders
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Particularly IBS-C is characterized by abdominal pain or discomfort improved by defecation, whereas functional constipation is a functional bowel disorder that presents as persistently difficult, infrequent, or incomplete defecation. Functional defecation disorders are characterized by paradoxical contraction or inadequate relaxation of the pelvic floor muscles during attempted defecation (dyssynergic defecation ) or inadequate propulsive forces during attempted defecation (inadequate defecatory propulsion) (Bharucha et al. 2006).

Rectal hyposensitivity is a relatively new disorder defined by Gladman (Gladman et al. 2003) as an elevation beyond the normal range in the perception of at least one of the sensory threshold volumes during anorectal manometry. There are as yet no specific criteria that can differentiate the subtypes of chronic constipation based on history (Bharucha et al. 2006). Also performing a full assessment of defecation using specific tests (e.g., anorectal manometry, colonic transit time, and defecography) may not distinguish these different conditions (Wong et al. 2010; Rey et al. 2014; Jones et al. 2007; Gambaccini et al. 2013). However, a careful attempt to understand the pathophysiological mechanisms underlying the constipation of each patient is mandatory in order to suggest an effective therapy. This should be strictly tailored to each individual patient and therefore different from one patient to another (Bellini et al. 2015).

Even if there are no specific criteria that can definitely distinguish among the different subtypes of chronic constipation, a careful medical history should always be collected. It is the first approach to the patient and is aimed to detect symptoms and events possibly linked to the onset of symptoms themselves (Bove et al. 2012).

History can also identify alarm symptoms (Table 24.5), such as weight loss, bloody stools, anemia, or a family history of colon cancer and conditions and/or diseases potentially associated with constipation, such as dietary mistakes (Altringer et al. 1995); low physical activity (Diamant et al. 1999); the use of constipating drugs; metabolic, psychiatric, or neurological diseases; and previous perineal-pelvic-abdominal or obstetric-gynecological surgery (Tables 24.1 and 24.2). In case of alarm symptoms/signs, colonoscopy is recommended (Table 24.10).

Table 24.5 Clinical approach to constipation
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Also assessing the stool form using the Bristol stool form score (Lewis and Heaton 1997) is of paramount importance to obtain an objective evaluation; moreover stool consistency is considered an indicator of colonic transit ; hence, it can address the diagnosis.

A physical examination is essential in the initial workup of a patient with chronic constipation (Lindberg et al. 2011). The examination can detect a possible gastrointestinal mass and should include inspection of the anorectal region and exploration of the rectum. This process can provide evidence of external signs of anal disease, pelvic organ prolapse, or descending perineum syndrome. A digital rectal examination should detect any signs of organic disease or obstructed defecation (rectal masses, fecal impaction, stricture, rectal intussusception, or rectocele). The examination is particularly important if functional alterations in defecation are suspected in order to evaluate puborectal and anal sphincter activity.

Blood tests do not provide useful input in functional constipation but can be performed to exclude conditions of secondary chronic constipation (Bove et al. 2012) (Table 24.2). They also can be mandatory when alarm symptoms are present.

Once excluded on a clinical basis organic lesions and secondary constipation, many patients will benefit from abolishing or reducing medications that cause constipation and recommending changes in lifestyle and diet with correct fluid (at least 1.5 l/day) and fiber (25 mg/day) intake (Table 24.6).

Table 24.6 Stepwise approach to chronic constipation
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If this management is not sufficient, it is mandatory to move to a second step encompassing the use of fiber supplementations and osmotic laxatives .

If also these therapies are ineffective, it is possible to use old (stimulant, softening, or saline) laxatives or new prokinetics or prosecretory agents even if in this subset of patients, further tests such as anorectal manometry and/or entero-defecography and/or colonic transit time are advisable, in order to better characterize the type of constipation (Tables 24.7, 24.8, and 24.9) and to evaluate other therapeutic options (e.g., pelvic floor rehabilitation , sacral nerve stimulation, anorectal surgery) (Ratto et al. 2015); colpo-cysto-entero-defecography (Altringer et al. 1995; Maglinte et al. 1997), magnetic resonance (MR) defecography (Lienemann et al. 1997), and dynamic transperineal ultrasonography (DTP-US) (Beer-Gabel et al. 2002, 2004; Dietz and Steensma 2005; Brusciano et al. 2007) are also available and increasingly utilized. Colonic and/or gastrojejunal manometry should be performed in patients with serious slow-transit constipation because they can be helpful in the diagnosis and in decisions regarding therapy (whether conservative or surgical) (Bove et al. 2012).

Table 24.7 Stepwise approach to constipation refractory to high-fiber diet, laxatives, and prokinetic/prosecretory drugs
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Table 24.8 Diagnostic tools and relevant information provided (Pehl et al. 2002)
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Table 24.9 Interpretation of the manometric data (Bove et al. 2012)
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The global approach to chronic constipation integrating available tests and treatments is summarized in Table 24.10.

Table 24.10 Global stepwise approach to chronic constipation
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