The document provides an overview of anal conditions, covering the embryology, anatomy, histology, physiology, and diseases of the anal canal. It discusses the development of the anal canal from endoderm and ectoderm. Key topics include the internal and external anal sphincters, hemorrhoids, anal fissures, abscesses, fistulas, and anal cancer. Treatment approaches are outlined for various anal diseases.
3. Embryology
Anal canal develops from the endoderm and ectoderm (proctodeum)
Urorectal Septum:
Separates the cloche into the anal canal and urogenital sinus
Fuses with the cloacal membrane and separates it into the anal membrane and
the urogenital membrane
Proctodeum:
mesenchyme raises the surrounding ectoderm to form a shallow anal pit
Separated by the dentate line
Blood supply, lymphatics, innervation in the anal canal depend on the embryonic
origin
16. Anatomy
Above Dentate Line Below Dentate Line
Arterial Supply
Superior Rectal A.
(IMA)
Middle Rectal A.
Inferior Rectal A.
(Internal Pudendal)
Venous Drainage Superior and Middle Rectal Vs. Inferior Rectal V.
Lymphatic Drainage
Internal Iliac and Inferior
Mesenteric LNs.
Superficial Inguinal LNs.
Sphincter/Innervation
Internal Sphincter
(Autonomic Ns.)
External Sphincter
(Pudendal N.)
Sensory Not sensitive to pain Very sensitive to pain
19. Physiology
Tow Sphincters close the anal canal:
Internal Sphincter: Hypertrophied part of the circular layer of the muscularis:
Smooth muscles
Autonomic innervation (Sympathetic “contraction”, Parasympathetic “relaxation”
Opens when the rectum is distended (rectoanal inhibitory reflex)
contributes 55% of the resting pressure
External Sphincter: skeletal muscle that surrounds the anal canal
Striated muscles
Somatic innervation
Voluntary control
3 layers: deep, superficial, subcutaneous
Both sphincters are in continuous contraction
20. Anal Diseases
Hemorrhoids
Anal Fissures
Anorectal Sepsis and Cryptoglandular Abscess
Fistula In Ano
Pilonidal Disease “cyst, infection”
Perianal Dermatitis
Hidradenitis Suppurativa
Anal Sphincter Injury and Incontinence
Anal Cancer
21. Hemorrhoids “Rectal varices”
Hemorrhoids are cushions of submucosal tissue containing venules, arterioles, and
smooth muscle fibers that are located in the anal canal
3 cushions: left lateral, right anterior, and right posterior positions
skin tag: is redundant fibrotic skin at the anal verge, often persisting as the residual of
a thrombosed external hemorrhoid
3 Types:
External hemorrhoids: distal to the dentate line and are covered with anoderm
Internal hemorrhoids: proximal to the dentate line
Combined internal and external hemorrhoids
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23.
24. Hemorrhoids “Rectal varices”
Degrees:
1st degree hemorrhoids: may prolapse beyond the dentate line on straining
2nd degree hemorrhoids: prolapse, reduce spontaneously
3rd degree hemorrhoids: prolapse, require manual reduction
4th degree hemorrhoids: prolapse, cannot be reduced
risk for strangulation
Sings and Symptoms:
Asymptomatic
Pain, bleeding, prolapse mass, thrombosis
Portal hypertension
26. Hemorrhoids “Rectal varices”
Treatment:
Is only indicated if they become symptomatic
Medical Therapy: diet, pain control, laxatives, paths
Rubber Band Ligation
Infrared Photocoagulation
Sclerotherapy
Excision of Thrombosed External Hemorrhoids
Doppler-Guided Hemorrhoidal Artery Ligation
Hemorrhoidectomy “Treatment of choice”
27. Hemorrhoids “Rectal varices”
Complications of Hemorrhoidectomy:
Post-operative pain
Urinary retention
Fecal impaction due to pain
Bleeding, may be massive
Infection
transient incontinence to flatus
Permanent fecal incontinence
anal stenosis
Ectropion “Whitehead’s deformity”
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29.
30.
31. Anal Fissures “Anal Tears”
Pathophysiology:
Related to trauma to the anus (hard stool, prolonged diarrhea)
A tear in the anoderm causes spasm of the internal anal sphincter, which results in
pain, increased tearing, and decreased blood supply to the anoderm
85% midline posterior, 15% midline anterior, less than 1% off midline
Types:
acute fissure: is a superficial tear of the distal anoderm and almost always heals with
medical management
Chronic fissures: develop ulceration and heaped-up edges with the white fibers of
the internal anal sphincter visible at the base of the ulcer
34. Anal Fissures “Anal Tears”
Signs and Symptoms:
tearing pain with defecation
hematochezia
intense and painful anal spasm lasting for several hours after a bowel movement
skin tag and/or a hypertrophied anal papilla internally
No PR
Lateral fissures may be:
Chron’s Disease
HIV
Syphilis
TB
Leukemia
35. Anal Fissures “Anal Tears”
Treatment:
Reduce anal Trauma
Medical therapy: reduce pain, improve blood supply
is effective in most acute fissures, but will heal only approximately 50%
of chronic fissures
Local anesthesia
Nitroglycerin ointment
calcium channel blockers
Arginine
bethanechol
Surgical Treatment: lateral internal sphincterotomy is the procedure of
choice (30% of the internal sphincter ), or advancement flaps
95% success rate
39. Anorectal Sepsis and Cryptoglandular Abscess
Infection of an anal gland results in the formation of an abscess
Different spaces may be involved:
perianal abscess (M.C)
Intersphincteric abscesses
Ischiorectal Abscess
Pelvic abscesses
supralevator abscesses
Signs and Symptoms:
painful swelling at the anal verge
Inflammation signs and symptoms
urinary retention
Life-threatening sepsis
43. Anorectal Sepsis and Cryptoglandular Abscess
Treatment:
I&D as soon as the diagnosis is established
Antibiotics are only indicated if:
extensive overlying cellulitis
Immunocompromised
diabetes mellitus
valvular heart disease
44.
45. Anorectal Sepsis and Cryptoglandular Abscess
Notes:
Perianal Sepsis in the Immunocompromised Patient
The immunocompromised patient with perianal pain presents a diagnostic dilemma
No Signs & Symptoms of inflammation
Examination under anesthesia should not be delayed due to neutropenia
I&D + ATB
46. Anorectal Sepsis and Cryptoglandular Abscess
Necrotizing Soft Tissue Infection of the Perineum:
necrotic skin, bullae, or crepitus
high index of suspicion is necessary because perineal signs of severe infection
may be minimal
Surgical debridement + ATB
May require colostomy
High mortality (50%)
50% of patients develop fistula after treatment of cryptoglandular abscess
The fistula usually originates in the infected crypt (internal opening) and
tracks to the external opening, usually the site of prior drainage
47. Fistula In Ano
Fistula: abnormal connection between two types of epithelium
Causes:
Cryptoglandular abscess (M.C)
Trauma
Crohn’s disease
Malignancy
Radiation
Unusual infections (tuberculosis, actinomycosis, and chlamydia) may
also produce fistulas
48. Fistula In Ano
Symptoms and Findings:
persistent drainage from the internal and/or external openings
External opening as a red elevation of granulation tissue
Hydrogen peroxide or dilute methylene blue test may be used
Goodsall’s rule:
fistulas with an external opening anteriorly connect to the internal opening
a short, radial tract
Fistulas with an external opening posteriorly track in a curvilinear fashion to
the posterior midline
exceptions to this rule often occur if an anterior external opening is greater
than 3 cm from the anal margin (track to the posterior midline)
53. Fistula In Ano
Treatment:
Depend on the internal and external openings location and the involvement of the
sphincter complex
Intersphincteric needs only fistulotomy
Transsphincteric and suprasphincteric require Seton before fistulotomy
• up to 30% loss of sphincter is accepted
• Seton drains, cutting setons, non-cutting setons
Extrasphincteric, the portion of the fistula outside the sphincter should be opened
and drained
endorectal advancement flap
Fibrin glue
Ligation of the intersphincteric fistula tract (LIFT)
54. Fistula In Ano
Rectovaginal fistula: connection between the vagina and the rectum or anal canal proximal
to the dentate line
Classification:
Low: opens in the fourchette
Middle: opens between the fourchette and cervix
High: opens near the cervix
Causes:
After surgical resection of a midrectal neoplasm
Radiation injury
Extension of an undrained abscess.
Complicated diverticulitis
Crohn’s disease
55. Fistula In Ano
Diagnosis:
sensation of passing flatus from the vagina to the passage of solid
stool from the vagina
some degree of fecal incontinence
vaginitis
barium enema or vaginogram
methylene blue
Treatment: depends on the size, location, etiology, and condition of surrounding tissues
Low and mid-rectovaginal fistulas: best with endorectal advancement flap +/-
overlapping sphinectroplasty
High-rectovaginal fistulas: transabdominal approach (resection with closure)
57. Pilonidal Disease “cyst, infection”
Hair-containing sinus or abscess occurring in the intergluteal cleft
May become infected
Etiology: unknown
Diagnosis:
Inflammatory signs with a tough swelling
Treatment:
Incision and drainage
Excision
Wound care
60. Perianal Dermatitis
Idiopathic and probably related to local hygiene, neurogenic, psychogenic (M.C)
Treatment:
removal of irritants
improving perianal hygiene
dietary adjustments
avoiding scratching
Local medications
If chronic or not responding to treatment, may require a biopsy
61. Hidradenitis Suppurativa
Infection of the cutaneous apocrine sweat glands
Mimic complex anal fistula disease, but stops at the anal verge because there are no apocrine
glands in the anal canal
Treatment:
incision and drainage of acute abscesses
unroofing of all chronically inflamed fistulas and debridement of granulation tissue
Radical excision
62. Anal Sphincter Injury and Incontinence
The most common cause of anal sphincter injury is obstetric trauma during vaginal
delivery
Rectal injury accompanied by sphincter injury should be treated with fecal diversion and
distal rectal washout, with or without drain placement
Treatment: for isolated sphincter injury
wrap-around sphincteroplasty
Postanal intersphincteric levatorplasty
Gracilis muscle transposition with or without chronic, low-frequency
electrostimulation
Artificial anal sphincter
Sacral nerve stimulation
Fecal diversion
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64.
65. Anal Cancer
Rare
Risk Factors:
Human papillomavirus (HPV)
Human immunodeficiency virus (HIV)
Cigarette smoking
Multiple sexual partners
Anal intercourse
Immunosuppressed state
Signs and Symptoms:
Often asymptomatic
Bleeding, lump, itching, ulcer
67. Anal Cancer
Treatment:
Epidermoid carcinoma of anal canal: Chemoradiation is mainstay—5-FU, mitomycin C,
and external beam radiation (Nigro protocol) surgery is reserved or recurrence
Other anal margin tumors: Wide local excision alone or in combination with
radiation and/or chemotherapy is successful in 80% o cases without abdominalperineal
resection (APR) if tumor is small and not deeply invasive
Anal canal tumors: Local excision not an option; combined chemotherapy
(5-FU and mitomycin C) with radiation o ten successful; APR if chemoradiation fails