Conceptos actuales de patología anorrectal funcional / Current concepts in functional anorectal disorders

The purpose of the present article is to highlight relevant aspects of anorectal pathology, mainly fiber resistant constipation, fecal incontinence and fecal soiling. A high percentage of patients with fiber resistant constipation correspond to dyssynergic defecation cases. In addition, most patients with dyssinergia and slow colonic transit return to normal after correction of the dyssyinergic condition. For these reasons, the current recommendation is to consider the evaluation of dyssynergic defecation as the initial diagnostic approach in patients with laxative-resistant constipation. Rectal hyposensitivity is an important pathophysiological mechanism involved in both constipation and fecal incontinence. About 80% of fecal incontinence cases present multiple pathological mechanisms, including sphincter insufficiency, rectal hyposensitivity, poor rectal emptying and impaired rectal compliance. Soling and seepage are usually in the context of poor rectal emptying and not in the context of sphincter insufficiency.

El siguiente artículo pretende destacar aspectos relevantes en patología anorrectal funcional, principalmente constipación resistente a fibra, incontinencia fecal y ensuciamiento. Entre los pacientes con constipación resistente a fibra, un alto porcentaje corresponde a defecación disinérgica. Además, la mayoría de los pacientes con defecación disinérgica y tránsito colónico enlentecido normalizan el tránsito tras mejoría de la disinergia. Por estos motivos, la recomendación actual es la evaluación de defecación disinérgica como primera estrategia diagnóstica en los pacientes con constipación refractaria a laxantes. La hiposensibilidad rectal es un mecanismo importante en casos de constipación e incontinencia fecal. Alrededor de 80% de los casos de incontinencia fecal tienen múltiples mecanismos descritos, incluyendo insuficiencia esfinteriana, hiposensibilidad rectal, mal vaciamiento rectal y alteraciones de la complianza rectal. El ensuciamiento suele estar en el contexto de mal vaciamiento rectal y no en el contexto de insuficiencia esfinteriana.

Rectal hyposensitivity and functional anorectal outlet obstruction are common entities in patients with functional constipation but are not significantly associated

BACKGROUND/AIMS: The causes of functional anorectal outlet obstruction (outlet obstruction) include functional defecation disorder (FDD), rectocele, and rectal intussusception (RI). It is unclear whether outlet obstruction is associated with rectal hyposensitivity (RH) in patients with functional constipation (FC). The aim of this study was to determine the association between RH and outlet obstruction in patients with FC. METHODS: This was a retrospective study using a prospectively collected constipation database, and the population comprised 107 patients with FC (100 females; median age, 49 years). We performed anorectal manometry, defecography, rectal barostat, and at least two tests (balloon expulsion test, electromyography, or colon transit time study). RH was defined as one or more sensory threshold pressures raised beyond the normal range on rectal barostat. We investigated the association between the presence of RH and an outlet obstruction such as large rectocele (> 2 cm in size), RI, or FDD. RESULTS: Forty patients (37.4%) had RH. No significant difference was observed in RH between patients with small and large rectoceles (22 [44.9%] vs. 18 [31%], respectively; p = 0.140). No significant difference was observed in RH between the non-RI and RI groups (36 [36.7%] vs. 4 [30.8%], respectively; p = 0.599). Furthermore, no significant difference in RH was observed between the non-FDD and FDD groups (19 [35.8%] vs. 21 [38.9%], respectively; p = 0.745). CONCLUSIONS: RH and outlet obstruction are common entities but appear not to be significantly associated.

Rectal Hyposensitivity

Impaired or blunted rectal sensation, termed rectal hyposensitivity (RH), which is defined clinically as elevated sensory thresholds to rectal balloon distension, is associated with disorders of hindgut function, characterised primarily by symptoms of constipation and fecal incontinence. However, its role in symptom generation and the pathogenetic mechanisms underlying the sensory dysfunction remain incompletely understood, although there is evidence that RH may be due to 'primary' disruption of the afferent pathway, 'secondary' to abnormal rectal biomechanics, or to both. Nevertheless, correction of RH by various interventions (behavioural, neuromodulation, surgical) is associated with, and may be responsible for, symptomatic improvement. This review provides a contemporary overview of RH, focusing on diagnosis, clinical associations, pathophysiology, and treatment paradigms.

Clinical Characteristics of Constipation with Hypothyroidism

BACKGROUND/AIMS: Constipation is a well-recognized gastrointestinal symptom in patients with untreated hypothyroidism. Although thyroid function tests are recommended to exclude hypothyroidism in patients with constipation, there have been no reports to determine the causal relationship between thyroid function and constipation. The aim of this study was to determine the prevalence of hypothyroidism in constipated patients and the clinical features of constipation associated with hypothyroidism. METHODS: A total of 1,481 constipated patients were included. These patients were divided into overt hypothyroidism, subclinical hypothyroidism, and normal thyroid function groups based on thyroid function tests. We reviewed the clinical presentation, anorectal function, colonic transit time, defecographic findings, and response to biofeedback therapy. RESULTS: The prevalence of overt and subclinical hypothyroidism was 0.41% (men, 0.36%; women, 0.53%) and 1.76% (men, 1.28%; women 2.03%), respectively. There were no differences in total or segmental colonic transit times and subtypes of constipation among the normal thyroid function (n=54), overt hypothyroidism (n=4), and subclinical hypothyroidism groups (n=21). On anorectal manometry, the prevalence of dyssynergic defecation did not differ between the three groups. Rectal hyposensitivity was more frequent in the overt hypothyroidism group (overt hypothyroidism group, 50.0%; subclinical hypothyroidism group, 19.0%; normal thyroid function group, 20.4%) without statistical significance (P=0.372). CONCLUSIONS: The prevalence of overt and subclinical hypothyroidism in constipated patients was very low. The colonic transit time is not affected by thyroid function.

Clinical Characteristics of Constipation with Hypothyroidism

BACKGROUND/AIMS: Constipation is a well-recognized gastrointestinal symptom in patients with untreated hypothyroidism. Although thyroid function tests are recommended to exclude hypothyroidism in patients with constipation, there have been no reports to determine the causal relationship between thyroid function and constipation. The aim of this study was to determine the prevalence of hypothyroidism in constipated patients and the clinical features of constipation associated with hypothyroidism. METHODS: A total of 1,481 constipated patients were included. These patients were divided into overt hypothyroidism, subclinical hypothyroidism, and normal thyroid function groups based on thyroid function tests. We reviewed the clinical presentation, anorectal function, colonic transit time, defecographic findings, and response to biofeedback therapy. RESULTS: The prevalence of overt and subclinical hypothyroidism was 0.41% (men, 0.36%; women, 0.53%) and 1.76% (men, 1.28%; women 2.03%), respectively. There were no differences in total or segmental colonic transit times and subtypes of constipation among the normal thyroid function (n=54), overt hypothyroidism (n=4), and subclinical hypothyroidism groups (n=21). On anorectal manometry, the prevalence of dyssynergic defecation did not differ between the three groups. Rectal hyposensitivity was more frequent in the overt hypothyroidism group (overt hypothyroidism group, 50.0%; subclinical hypothyroidism group, 19.0%; normal thyroid function group, 20.4%) without statistical significance (P=0.372). CONCLUSIONS: The prevalence of overt and subclinical hypothyroidism in constipated patients was very low. The colonic transit time is not affected by thyroid function.

Esophageal Sensation and Esophageal Hypersensitivity: Overview From Bench to Bedside

Noxious stimuli in the esophagus activate nociceptive receptors on esophageal mucosa, such as transient receptor potential, acid-sensing ion channel and the P2X family, a family of ligand-gated ion channels responsive to ATP, and this generates signals that are transmitted to the central nervous system via either spinal nerves or vagal nerves, resulting in esophageal sensation. Among the noxious stimuli, gastric acid and other gastric contents are clinically most important, causing typical reflux symptoms such as heartburn and regurgitation. A conventional acid penetration theory has been used to explain the mechanism of heartburn, but much recent evidence does not support this theory. Therefore, it may be necessary to approach the causes of heartburn symptoms from a new conceptual framework. Hypersensitivity of the esophagus, like that of other visceral organs, includes peripheral, central and probably psychosocial factor-mediated hypersensitivity, and is known to play crucial roles in the pathoegenesis of nonerosive reflux disease, functional heartburn and non-cardiac chest pain. There also are esophagitis patients who do not perceive typical symptoms. This condition is known as silent gastroesophageal reflux disease. Although the pathogenesis of silent gastroesophageal reflux disease is still not known, hyposensitivity to reflux of acid may possibly explain the condition.

Response to Biofeedback Therapy for Patients with Rectal Hyposensitivity

BACKGROUND/AIMS: Rectal hyposensitivity (RH) has been treated with conventional biofeedback therapy (BFT), whereas the effectiveness and long term results of this therapy are not known. We aimed to investigate the effectiveness of BFT for patients with RH by conducting a retrospective review of prospectively collected data. METHODS: From June 2004 to March 2007, we enrolled those RH patients who underwent BFT. BFT was performed two or three times every week. Six months after BFT, the clinical response was evaluated by subjective and objective parameters. RESULTS: A total of 82 RH patients underwent BFT. Fifty three patients finished BFT and the other 29 patients dropped out during BFT. Thirty six patients (67.9%) showed responsiveness (R) to BFT and 17 (31.5%) showed non-responsiveness (NR). The characteristics between the two groups showed no difference, except for the "desire to defecate" volume (116.1+/-25.2 in the R group vs. 140.0+/-43.9 in the NR group, p value <0.05) and the rectoanal inhibitory reflex (RAIR) (15.6+/-0.5 in the R group R vs. 27.6+/-18.2 in the NR group, p value <0.05). The R group showed a shorter colon transit time compared to NR group. At six months after BFT, a total of 20 patients were interviewed; 15 patients answered that they still had responsiveness (75%). CONCLUSIONS: The patients with RH showed a similar BFT response to that of the constipated patients. However, the patients with a more hyposensitive rectum and a longer colonic transit showed NR to BFT, suggesting RH is an important factor in BFT responsiveness.