Minor Anorectal Conditions in Proctology

Research Article

Austin J Surg. 2018; 5(5): 1142.

Minor Anorectal Conditions in Proctology

Weledji EP*

Department of Surgery, Faculty of Health Sciences, University of Buea, Cameroon

*Corresponding author: Elroy Patrick Weledji, Department of Surgery, Faculty of Health Sciences, University of Buea, S.W. Region, PO Box 126, Limbe, Cameroon

Received: February 16, 2018; Accepted: April 13, 2018; Published: April 20, 2018


The article describes a guide to the clinical features, diagnosis and management of some common benign anorectal disorders. Many tests are available to investigate anorectal disorders, each only providing part of a patient’s assessment, so results should be considered together and alongside the clinical picture derived from a careful history and physical examination. Normal pelvic floor function relies on a complex interplay between various mechanisms. The indications for anorectal imaging may be divided into three broad clinical areas: sepsis and fistula disease, malignancy and faecal incontinence. A wide range of investigations are required in most anorectal disorders as there is usually more than one contributing factor. Anorectal pathology is a growing problem with a greater need for understanding sexually-transmitted diseases in the practice of proctology.

Keywords: Benign; Anorectal disease; Sexually-transmitted infections; Treatment


Anatomy and physiology of the anal Canal

The adult anal canal is approximately 4 cm long and begins as the rectum narrows passing backwards between the levator ani muscles. It has the upper limit at the pelvic floor and the lower limit at the anus. The anorectal ring at the commencement of the anal canal can be accurately palpated on digital rectal examination because of the prominent fibres of the puborectalis sling. The muscles of the anal sphincter form a tube within a funnel. The sides of the upper part of the funnel are levator ani with the external sphincter making the stem of the funnel. The tube within the funnel includes the lower rectal muscularis propria and the internal sphincter. The circular muscle of the rectum becomes thicker (1-5mm) as it forms the internal anal sphincter. The conjoint longitudinal coat is a thin fibroelastic sheet that passes between the internal and external sphincters. It is formed by fusion of the outer longitudinal layer of rectal muscle with the fibrous components of puborectalis. It separates the two sphincters creating the intersphincteric space. The external anal sphincter, made of striated muscle is 6-10mm thick, innervated by the pudendal nerve (S2-4), and surrounded by the superficial fascia of the ischiorectal fossa and perianal subcutaneous tissue. It is attached to the coccyx posteriorly by the anococcygeal raphe and to the perineal body anteriorly [1-3]. The proximal canal is lined by simple columnar epithelium, changing to stratified squamous epithelium lower in the canal via an intermediate transition zone just above the dentate line. This zone plays a critical role in the sensory function of the anal canal and eliciting continence. Increasing rectal distension is associated with transient reflex relaxation of the internal anal sphincter and contraction of the external anal sphincter, known as the rectoanal inhibitory reflex [4]. This reflex may enable rectal contents to be sampled by the transition zone mucosa to enable the discrimination between solid, liquid and flatus [5]. Anal glands that secrete mucus empty into small pockets above the anal valves located in the dentate line called anal crypts. The glands are mostly submucosal and some penetrate into the internal sphincter. Infection within these glands may result in perianal or ischiorectal abscesses and fistulae in ano [1,2]. Beneath the mucosa is the subepithelial tissue, composed of connective tissue and smooth muscle. This layer increases in thickness throughout life and forms the basis of the vascular cushions thought to aid continence by accounting for up to 15% of resting anal pressure acting as an effective barrier against mucus and fecal material [2]. If this junction prolapses, as in patients with haemorrhoids, such that it comes to lie outside the highpressure zone, then this barrier function fails and patients experience faecal spotting [1-3]. The internal anal sphincter has an intrinsic nerve supply from my enteric plexus together with an additional supply from both the sympathetic (superior and inferior hypo gastric plexuses) and parasympathetic nervous systems (nervi erigentes- S2-4). Sympathetic activity enhances and parasympathetic reduces internal sphincter contraction. Anorectal physiological studies provide measurements of the resting and squeeze pressures along the canal and between 60% and 85% of resting anal pressure can be attributed to the action of the internal anal sphincter. The external anal sphincter and the puborectalis muscle generate maximal squeeze pressure [6]. Thus symptoms of passive anal leakage are attributed to internal sphincter dysfunction, whereas urge symptoms and frank incontinence of faeces are due to external sphincter problems [7,8]. As a result of this complex interplay between continence factors and faecal evacuation, and,as in most clinical situations of anorectal disorders there is more than one contributing factor a wide range of investigations may be needed for full assessment [9].

Clinical assessment

Anal disorders usually present with bleeding at the time of defaecation, pruritus (itching) ani, pain on defaecation, perianal swelling or discharge (faecal, mucus or pus). Clinical examination is an essential feature of assessment of any patient with symptoms attributable to the anal canal and the rectum and colon must always be examined to ensure that the underlying cause is not proximal. The causes of rectal bleeding as a symptom are shown in (Table 1). The patient is placed in the left lateral position and the examination comprises three components: inspection, palpation and endoscopy (proctoscopy, sigmoidoscopy or colonoscopy if necessary). If investigation is impossible in the outpatient department, it can be done under anaesthetic (EUA), particularly when pain and discomfort prevent digital palpation. The wide range of investigations is needed for full assessment as in most clinical situations of anorectal disease there is more than one contributing factor or there may be coexisting diseases. Sphincter function may be assessed using anal manometry and electrophysiology, whereas sphincter anatomy may be assessed using anal endosonography (AES) and MRI. The former being the standard for the diagnosis of sphincter trauma. Dynamic MRI and evacuation proctography are useful in the assessment of patients with evacuatory disorders. Pelvic MRI is the best imaging modality for anorectal sepsis and can predict recurrence of complex anal fistulas after surgery, although three-dimensional AES provides a useful alternative [10,11].