Rectum And Anus Flashcards
Layers of the colon and rectum:
- mucosa
- submucosa
- Inner circular muscle ( creats the internal anal sphincter)
- outer longitudinal muscle
- serosa
Anatomical anal canal made of =
Surgical anal canal made of=
Dentate line and anal verge
-anorectal ring, dentate line and anal verge
Colorectal and anorectal vascular supply:
Arterial supply for the colon: 1) superior mesenteric artery branches ▪️ileocolic artery ▪️ right colic artery ▪️middle colic artery 2)inferior mesenteric artery; ▪️left colic artery ▪️sigmoid branches ▪️superior rectal artery 3)internal iliac artery branches: ▪️middle rectal artery ▪️internal pudendal artery branch
Venous drainage:
1) superior rectal vein
2) middle rectal vein
3) inferior rectal vein
Colorectal and anorectal nerve supply:
- parallel to the course of arteries:
1) sympathetic (inhibitory) arise from t6-t12 and L1-L3
2) parasympathetic (stimulatory) , vagus nerve to right and trnasverse colon , s2-s4 left colon - external anal sphin. And pubotectalis muscle -> internal pudendal nerve
- levator ani- internal pudendal nerve +branches od s3-s5
Anal canal is sensate
Rectum is relatively insensate
Clinical evaluation :
🔸endoscopy:
1) anoscopy: examination of the anal canal , it can be diagnostic and therapeutic tool
2) proctoscopy: examination of the rectum and distal sigmoid colon , occasionally used therapeutically
Imaging:
1) plain x ray of abdomen
2) contrast studies
3) CT
4) MRI
5) Positron emission tomography(PET)
6) angiography
7) endorectal and endoanal US
Anorectal Hemorrhoids:
- cushions of submucosal tissue containing venules , arteriols and smooth muscle fibers that are located in the anal canal
- 3cushions : left lateral, right anterior and right posterior , thought to function as part of the continence mechanism
Classification of hemorrhoids:
1) external hemorrhoids -distal to dintate line
2) internal hemorrhoids - proximal to dintate line ( are grouped into 4 stages , 1: that bleed, 2: cause bleeding and prolapse but return by themselves, 3:bleed and prolapse but require manual replacement , 4: do not return into anal canal
3) combined internal and external horrhoids
4) postpartum hemorrhoids
5) rectal varices: may result from portal hypertension
Treatment of hemorrhoids:
✅medical therapy : (dietary fiber , stool softeners , increased fluid intake and avoidance of straining ) STAGE 1+2
✅rubber band ligation , sclerotherapy , infrared photocoagulation, laser ablation, carbon dioxide freezing, lord dilation
1 +2 and selected 3 hemorrhoids
✅excision of thrombosed external hemorrhoids
Sclerotherapy=
Treatment of early internal hemorrhoids
Operative hemorrhoidectomy=
Based on decreasing blood flow to the hemorrhoidal plexuses and excising redundant anoderm and mucosa
1) closed submucosal hemorroidectomy
2) open hemorroidectomy
3) stapled hemorrhoidectomy
* preoperative details= performed by using local anesthesia with IV sedation or general/regional anesthetic techniques + simple rectal evaquation
Complications of hemorroidectomy:
1) postoperative pain - oral narcotics , NSAIDs, muscle relaxants , topical analgesics
2) urinary retention
3) fecal impaction
4) bleeding
5) infection
6) long term sequelae :
a. inconteninece
b. anal stenosis
Anal fissure=
Tear in the andoderm distal to the dentate line
- symptoms: tearing pain with defecation and hematochezia , pts are often too tender to tolerate DRE, anoscopy or proctoscopy
- acute fissure always heal with medical management
- chronic fissures develop ulcerationsl and heaped up edges , may require surgery
Treatment of anal fissure :
1) dietary changes : bulk agents, stool softeners and warm sitz bath
2) topical agents: lidocaine jelly or analgesic creams , nitroglycerin ointment , oral and topical diltiazem and topical nefidipine
3) botulinum toxin
4) surgical sphincterectomy for chronic fissures that failed medical therapy
Anorectal sepsis and cryptoglandular abscess:
Infection of an anal gland in the intersphincteric space -formation of an abscess that enlarges and spreads along one of several planes in the perianal and perirectal space
Diagnosis of anorectal sepsis and abscess:
▪️pain is the most common complaint
A palpable mass often is detected by DRE
▪️occasionally, pts will present with fever , urinary retention or sepsis
▪️the diagnosis of a perianal or ischiorectal abdcess can be made by physical exam only
Treatment of anorectal sepsis and abscess:
✅drainage as soon as the diagnosis is established
*antibiotics are only indicated if there is an extensive cellulitis or pt is immuno compromised, has DM or valvular disease
✅surgical treatment based on the location of abscess
Parks classification:
Defining 4 major types of anorectal fistulas
Type1: intermuscular (70%)- between enternal and external sphincters
Type2: trans sphincteric (23%) through the external sphincter into the ischiorectal fossa
Type3: extrasphincteric(5%) from rectum to skin
Type 4: suprasphincteric(2%)
Imaging studies for anal fistulas:
▪️fistulography ▪️endoanal/endorectal ultrasound ▪️MRI ▪️CT ▪️Barium enema/ small bowel series
Diagnostic procedures of anal fistulas:
Examination of the perineum, DRE, anoscopy are performed after anesthesia
Proctosigmoidoscopy/ clonoscopy
Treatment of anal fistulas :
✅fistulotomy/ fistulectomy
✅seton placement (cutting or no cutting seton)
✅fibrin glue has been used to treat persistent fistulas with variable results
Rectal prolapse:
Is a protrusion of the full thickness of the rectum through the anus
▪️cuases: colonic inssusception or sliding hernia,increased intra abdominal pressure , seen more common in elderly
Clinical presentation of rectal prolapse:
Pt complains of prolapse , rectal bleeding , discharge.
Treatment of rectal prolapse:
✅surgical treatment combines of bowel resection and rectal fixation.
1) ant. Resection and suture fixation
2) the ripstein procedure
3) the thiersch loop
Anal cancer risk factors :
🔸95% associated with HPV
-human papilloma virus , papovavirus
-most common viral sexually transmitted disease
🔸HPV( high risk serotypes : hpv16 and 18 )
Prevention and screening for anal cancer :
🔸vaccination: recombinant HPV Quadrivalent vaccine (HPV4)
🔸screening method :
-physical examination : anal exam ,DRE, anoscopy
-anal pap smear
-high resolution anoscopy
Anal lesions :
Perianal lesions :
🔸Lesions that are not visible or are incompletely visible
🔸lesions that are completely visible
Treatment of anal cancer:
HPV Dysplasia : -LSIL= low grade condyloma -HSIS=high grade =carcinoma in situ ✅topical treatments: -podofilox 0.5% gel -Imiquimod -Trichloracetic acid ✅surgical method: -excision -cryotherapy -fulguration -electrodesication
