Lower Gastrointestinal Surgery Flashcards
What causes an enterocutaneous fistula?
An enterocutaneous fistula is an abnormal communication between the bowel and the skin, that is often accompanied by intra-abdominal abcesses. Most cases develop after surgery for imflammatory bowel disease, cancer, or lysis of adhesions. These complications usually occur in patients who are poorly prepared, who have had radiation therapy, in emergency surgery, or because of poor surgical judgement. Anastomotic breakdown, sepsis, and traumatic enterotomy (incision into bowel) are common predisposing procedures. Less commonly, enterocutaneous fistulas occur as part of the disease process in Crohn’s disease or diverticulitis. They often develop in patients who have done poorly for 4-6 days post-op. There is fever, persistant ileus, development of abcesses, dehydration, aneamia, malnourishment, and leakage of intestinal contents from the wound.
What are the main complications of enterocutaneous fistulas?
- Electrolyte disturbances
- Malnutrition
- Severe Sepsis (anastomotic leaks, abcesses, and cutaneous sepsis caused by irritation of enteric effluent)
How do you classify enterocutaneous fistulas?
Low Output: less than 200mL per 24 hours
Moderate Output: between 200-500mL per 24 hours
High Output: greater than 500mL per 24 hours
Moderate or high output fistulas are usually related to the small bowel. Higher output fistulas are more prone to electrolyte imbalance and malnutrition.
How do you manage an enterocutaneous fistula?
- Provide Bowel Rest. Consider enteral and parenteral nutrition
- Carefully monitor fluid output from the fistula
- Carefully monitor and manage electrolytes.
- Somatostatin (Octreotide) to reduce fistula output
- H2 antagonists may prevent bleeding from gastric stress ulceration
- Skin care management via a enterostomal nurse
- Control of sepsis (tx with broad spectrum gram negative and anearobe cover if indicated)
- Ambulation/TEDs/subcut heparin.
- CT scan to detect abcesses
- Sinography
- Contrast small bowel follw through, or contrast enema to investigate for any distal obstruction.
What factos help predict whether or not an enterocutaneous fistula is likely to close?
- Ileal and gastric fistulas are less likely to close than lateral oesophageal, lateral duodenal, and jejunal fistulas, or pancreatic and biliary fistulas.
- High output worse than low output
- Worse with IBD, radiation, malignancy
- Loss of intestinal continuity
- Persistant intestinal obstruction distal to the fistula
- Large adjacent abcess cavity
- Presence of a foreign body (eg. sutures, gauze, or prothesis)
- Epithelialisation of fistula
What are the anatomic features associated with rectoal prolapse?
Anatomic features associated with rectal prolapse include:
-deep peritoneal cul-de-sac
-a long mesorectum and poor posterior fixation of the rectum
-a redundant rectosigmoid
-a lax and atonic levator ani
In some cases functional disturbances result from chronic and prolonged straining against a pelvic floor that does not relax concomitantly. The pelvic muscles become stretched, the perineum descends stretching over the pudendal nerve. Pudendal neuropathy leads to further deenervation of anal sphincters and puborectalis. In 50% of patients, feacal incontinence occurs due to progressive deenvervation of the internal and external anal sphincters.
What is an occult rectal prolapse?
An occult rectal prolapse is caused by intersussception of the full thickness of the rectum, which does not protrude through the anal canal and may represent an early stage of complete prolapse.
What is a mucosal rectal prolapse?
A mucosal rectal prolapse is a protrusion of the rectal mucosa through the anal canal, and may be circumferential.
What is a complete rectal prolapse?
A complete rectal prolapse (proincidentia) is defined as a full-thickness rectal protrusion through the anal orifice.
What is the typical presentation of a rectal prolapse?
-Prolapsing anorectal lump, which may occur only at defeacation or may occur with coughing or walking or even spontaneously.
-Rectal Bleeding
-Mucous discharge
-Tenesmus
Associated feacal incontinence (50%), constipation causing straining, concomitant uterine prolapse or cystoceale, solitary rectal ulcer syndrome.
How do you differentiate between rectal prolapse and rectal heameorrhoids?
Rectal prolapse can be difficult to distinguish from extensive prolapsing heamorrhoids. With rectal prolapse, concentric rings of mucosa line the prolapsed tissue, and a sulcus is present between the anal canal and the rectum. Two layers of the rectal wall are palpated. Heamorrhoids are seperated by radial grooves and the sulcus is absent.
How do you treat rectal prolapse?`
Conservative management is generally prescribed for occult or mucosal rectal prolapse.
Elastic band ligation of the prolapsing anterior rectal mucosa can be helpful.
Those with persistant or unacceptable symptoms are treated surgically.
What are the main types of intestinal stomas?
- Ileostomies: end, loop. loop-end
- Colostomies; end, loop
- Ceacostomy
What is an end Ileostomy?
An end ileostomy is usually formed from the end of the terminal ileum. The end ileostomy can be revesible or permanent. It can be temporary when done inc onjunction with a subtotal abdominal colectomy for toxic colitis, left sided large bowel obstruction, or ischeamic bowel. The terminal ileum is drawn through an elliptical incision in the right lower quadrant, and a muscle splitting incision in the rectus muscle. A full thickness eversion of the bowel is then performed to obtain primary Brooke-Type maturation between the distal edge of the ileum and the dermis of the skin.
What is a proctocolectomy?
A proctocolectomy is the surgical removal of the rectum, and all or part of the colon. It can be used for Crohn’s disease of familial adenomatous polyposis. It used to result in a permanent end Ileostomy. However, there are now sphincter-saving procedures, such as a restorative proctocolectomy, that are used instead.
What is a loop ileostomy?
A loop Ileostomy is used temporarily to protect a distal anastomosis such as an ileal pouch-anal anastomosis or low colorectal anastomosis, or to divert stool from the distal anorectum such as for perianal Crohn’s disease, fungating anorectal cancer, severe perineal trauma or sepsis, and feacal incontinence. It is formed using a loop of the distal ileum delivered through the abdominal wall , usually in the right lower quadrant as for end ileostomy. A supporting rod is usually inserted through the mesentery under the apex of the ileal loop to releive tension. The afferent loop will be the larger of the two stomas. The afferent loop allows passage of stool output and the efferent loop allows passage of flatus and mucous discharge from the distal defunctioned portion of the bowel.
How do you manage an ileostomy?
Normal colour ranges from pink to deep red. Intestinal peristalsis usually recommences 2-5 days post surgery. Sometimes there is an early output of watery fluid (bowel sweat) before the return of bowel function. Oral feeding should be deferred until paralytic ileus has stopped. the rod of a loop ileostomy is removed 4-5 days post surgery.
As oedema subsides, the stoma is remeasured for new appliances about 4 weeks after construction. Ostomates should avoid nuts, popcorn, string vegetables, cabbage, oranges, or fruit peels.
What is the normal output for an ileostomy?
The normal ileostomy output ranges from 500mL-1000mL, higher outputs may result in dehydration, low output may indicate obstruction. A partial bowel obstruction may be associated with a high output of watery intestinal content.
What are the common comlications of an ileostomy?
Ischeamia, mucocutaneous seperation, parastomal abcess, fistula, bleeding, high output, ileostomy retraction, parastomal hernia or prolapse,small bowel obstruction, parastomal ulcer, skin irritation, ileostomy stricture.
What is an end sigmoid colostomy?
An end sigmoid colostomy may be temporary or permanent. The end stoma is permanent following an abdominoperineal resection of the rectum for malignant disease or for severe feacal incontinence not appropriate for a perineal repair. It may serve as a temporary stoma for feacal diversion in radiation proctitis, or following a Hartmann’s procedure for resection of the rectosigmoid with benign or malignant disease. The colostomy effluent is usually solid and non irritating as it has travelled through the colon. Thus is can be made flush with the skin without a spout.
What is a loop colostomy?
A loop colostomy may be constructed using a loop of the transverse or sigmoid colon. It serves as a temporary feacal diversion following a low colorectal anastomoses or for obstruction, inflammation, trauma, or perineal wounds. The loop may be brought through either the lower quadrant or the right upper quadrant. Whilst most loop colostomies are fully diverting in the first few months after construction, feacal diversion becomes incomplete in 20% of patients because of recession of the stoma.
What is a ceacostomy?
A tube ceacostomy using a No. 30 Fr Foley catheter is usually performed rather than a primary stoma. It is done for either colonic decompression or ceacal volvulus. The tube can be removed after 7-10 days and the ceacutaneous fistula should close spontaneously in the absence of a distal obstruction. However, a ceacostomy is not fully diverting and it is difficult to manage becuase of dislodgement or blackage of the tube. This procedure is rarely performed.
How do you manage a colostomy?
- Preoperative stoma siting and counselling
- Ileus 2-3 days post surgery
- Unlike an ileostomy (where you wait for passage of gas and effluent), colostomies need stimulation by ingestion of food before it begins to function.
- Ischeamia more common in colostomy
- Bulking agents
- Some patients may choose to undertake daily colostomy irrigations.
What are the complications of a colostomy?
Complications associated with a colostomy are similar to those associated with ileostomy but they differ in frequency. Parasternal hernias and stoma prolapse are more common. Strictures also occur more frequently. Food bolus obstruction and skin irritation are less common.
What is an anal fissure?
An anal fissure is a linear tear or superficial ulcer of the anal canal, extending from just below the dentate line to the anal margin. It usually occurs midline posteriorly, or sometimes anteriorly in females, particularly after a pregnancy. It presents with severe anal pain during and immediately after defecation and anal outlet bleeding. The pain is so intense that the patient avoids opening their bowels. The pain has been attributed to the spasm of the internal anal sphincter.
On inspection, what sign suggests that an anal fissure is chronic?
A chronic anal fissure will be associated with a sentinel skin tag at the anal margin, and a hypertrophied anal papilla at the upper end of the anal canal.
What is the differential diagnosis for anal fissures?
Differential diagnosis of anal fissures includes fissures due to Crohn’s disease, and neoplastic fissure. Fissures due to Crohn’s disease are usually not in the midline. They are deep, with indolent edges, tend to be multiple, painfree, and occur at atypical sites. Neoplastic ulcers are usually due to squamous cell carcinoma. The ulcer is deep and has heaped up edges. Also consider syphilis and HIV.
How do you treat anal fissures?
Conservative: apply topical anaesthetic and hydrocortisone ointment. High fibre diet to increase stool bulk (so the stool itself dilates the sphincter). 50% healed after 4 weeks. High recurrence rate. Glycerine trinitrate paste can be used to relax the internal sphincter.
Surgical: Lateral internal anal sphincterotomy; the distal internal sphincter is divided under anaesthesia. The large sentinel skin tag and hypertrophied anal papilla are excised. Recurence is <3%. Problems controlling flatus in 10%.
What is a Perianal abscess?
Perianal abscess is a common condition that is usually due to a blocked anal gland that subsequently becomes infected (cryptoglandular origin). There are usually no predisposing factors, but patients with diabetes, Crohn’s or are immunocomprimised are susceptible. The abcess may discharge spontaneously to the skin, and if communication to the skin is established then a fistula may result in up to 50% of patients. Patients present with throbbing pain, localised swelling, tenderness, and redness. May also have signs of fever and sepsis.
How do you treat perianal abscesses?
Incise and drain the abscess under local anaesthesia. Use antibiotics if the sepsis is extensive or if the patient is immunocompromised. If it usual to leave a small drain or packing gauze in the abscess cavity for a few days post operatively. A sigmoidoscopy should also be done of the rectal mucosa.
What is a fistula-in-ano?
A fistula is a communication between any two epithelial lined surfaces. A fistula-in-ano implies a direct communication between the anorectum and the perineal skin. The patient may present with recurrent perianal abscesses or with a bloody and purulent discharge. Pain and discomfort are usual. The external opening is usually visible on examination.
What is Goodall’s law?
Goodsall’s law indicates that fistulas with an anterior external opening drain directly into the anus at the dentate line, and those with a posterior external opening take a curved course to enter the anal canal in the midline. While the majority of fistulas probably conform to Goodsall’s law, there are some exceptions.
How do you treat fistula-in-ano?
Fistula-in-ano rarely heals spontaneously. Low Fistula: identify internal and external openings and ‘lay open’ the intervening track by fistulotomy (allowing the tract to heal by secondary intention).
High fistula: A fistulotomy may be contraindicated if there the internal opening is above the levator mechanism. In this patients, fistulotomy would include division of the levator, which would result in incontinence. Insert a seton in between the two openings, and it may act as a drain whilst being progressively tightened so that the tissue can heal.
For very complex fistulas, a proximal stoma may be formed to divert the faecal stream, in addition to other surgical manoeuvres.
What are the different causes of fistula-in-anos?
Idiopathic, anal gland infection, Crohn’s disease, iatrogenic, carcinoma, trauma (especially obstetric), foreign body (fish bone), radiation damage, tuberculosis, actinomycosis.
What is the typical presentation of anovaginal and rectovaginal fistulas?
The patient passes flatus or feaces via the vagina. Most commonly caused by obstetric trauma. Diagnosis made via examination under anaesthesia.
What are the most common types of anal cancers?
Most anal cancers are malignant epithelial tumours of the anal canal. The majority are squamous cell carcinomas (SCCs). HPV is a risk factor for anal cancer.
What is the anal transitional zone?
The anal transitional zone comes fro the epithelia that lines the upper third of the anal canal. It has a variable proximal extension into the lower rectum that is age dependent (broader in the elderly). It consists of a mixture of stratified squamous epithelium, stratified columnar epithelium, and cuboidal epithelium.
What is the typical presentation of anal cancer?
Anal cancer typically presents with bleeding or symptoms of pruritis ani, such as moisture, perianal itch, a burning sensation or pain after defecation, if the tumour is ulcerated and infected. It usually presents as an ulcer with typically rolled edges. The diagnosis must always be confirmed with incisional biopsy. It generally spreads upwards, and may spread via the lymphatics. It has a tendency to present at a late stage.
What is a pilonoidal sinus?
A pilonoidal sinus is an acquired chronic inflammatory condition in which hair becomes embedded in a midline pit or track, usually between the buttocks around the coccygeal region. It affects young hirsute males. They can present asymptomatically, with an abscess, or with chronic sepsis with discharge and discomfort.
