Anal Fissure

Definition and Epidemiology

Definition

• Superficial tear of the epithelial lining (anoderm) of the anal canal 
• Distal to the dentate line Dentate line Rectum and Anal Canal: Anatomy
• Acute fissures involve the epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium: Histology.
• Chronic fissures involve the full thickness of the anal mucosa.

Epidemiology

• Most common in infants and middle-aged adults
• Exact incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency unknown
• Males and females equally affected

Etiology and Pathophysiology

Etiology

• Acute fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes:
  • Forceful dilation of the anal canal (local trauma) due to:
    • Large, hard stools secondary to constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation
    • Irritating, diarrheal stools
    • Anal intercourse Anal intercourse Hemorrhoids
  • Other causes:
    • Habitual use of cathartics
    • Childbirth with 3rd- or 4th-degree perineal lacerations
• Chronic fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes:
  • Unhealed anal fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes
  • Previous anal surgery (possible stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) of the anal canal)
  • Crohn’s disease
  • Infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease
    • Tuberculosis Tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis
    • HIV HIV Anti-HIV Drugs
    • Chlamydia Chlamydia Chlamydiae are obligate intracellular gram-negative bacteria. They lack a peptidoglycan layer and are best visualized using Giemsa stain. The family of Chlamydiaceae comprises 3 pathogens that can infect humans: Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae. Chlamydia
    • Syphilis Syphilis Syphilis is a bacterial infection caused by the spirochete Treponema pallidum pallidum (T. p. pallidum), which is usually spread through sexual contact. Syphilis has 4 clinical stages: primary, secondary, latent, and tertiary. Syphilis
  • Leukemia
  • Squamous cell anal carcinoma

Pathophysiology

• Location: 90% posterior midline, 10% anterior midline
  • Most posterior midline fissures occur due to:
    • Shearing forces Shearing forces Vascular Resistance, Flow, and Mean Arterial Pressure during defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility
    • Decreased elasticity Elasticity Resistance and recovery from distortion of shape. Skeletal Muscle Contraction of the anal epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium: Histology
    • Increased density of longitudinal muscle extensions
  • Most anterior midline fissures occur from vaginal delivery
  • If the anal fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes is not midline, consider possible causes such as Crohn’s disease, infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, or anal cancer Anal cancer Anal cancer accounts for 2.7% of all gastrointestinal tract cancers. Squamous cell carcinoma is the most common type of anal cancer. The patient can present with rectal bleeding (most common), change in bowel habits, perianal pruritic mass, or perianal painful ulceration. Anal Cancer.
• Repetitive injury often occurs due to:
  • Local trauma
  • Anal hypertonicity Hypertonicity Volume Depletion and Dehydration
    • Tightening of the anal canal secondary to pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways leads to further tearing.
  • Sphincter spasm
    • Prevents edges from healing and leads to further tearing
  • Vascular insufficiency due to:
    • Increased sphincter tone 
    • Decreased perfusion from large anal canal circumference

Clinical Presentation

• Acute fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes
  • Symptoms: < 6 weeks
  • History:
    • Severe onset of anal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways with defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility; often lasts for hours afterward
    • Constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation
    • Hematochezia Hematochezia Gastrointestinal Bleeding (bright-red blood in stools)
  • Physical exam findings:
    • If anal fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes is suspected, avoid invasive examination (e.g., digital rectal exam or anoscopy).
    • Often appears as a superficial laceration Laceration Torn, ragged, mangled wounds. Blunt Chest Trauma in anal mucosa
• Chronic fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes
  • Symptoms: lasting > 6 weeks
  • Physical exam findings:
    • Tear in anal mucosa with possible visible fibers of anal sphincter
    • Sentinel skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions tags (external skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions tags)
    • Hypertrophied anal papillae Papillae Lips and Tongue: Anatomy

Diagnosis and Management

Diagnosis

• History is often classic and the basis of diagnosis.
• Confirmed on physical examination by:
  • Direct visualization
  • Reproducible anal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways with gentle palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination
• If fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes is not midline or history is more complicated, then additional testing may be warranted:
  • Anoscopy (when pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways has subsided)
  • Biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma
  • HIV HIV Anti-HIV Drugs testing
  • Stool cultures
  • Colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening/ sigmoidoscopy Sigmoidoscopy Endoscopic examination, therapy or surgery of the sigmoid flexure. Colorectal Cancer Screening as indicated (e.g., rectal bleeding)
  • Colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening and small bowel Small bowel The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy imaging if features of Crohn disease

Management

• Goals:
  • Eliminate constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation. 
  • Decrease anal spasms Spasms An involuntary contraction of a muscle or group of muscles. Spasms may involve skeletal muscle or smooth muscle. Ion Channel Myopathy.
  • Prevent further anal epithelial tears. 
  • Promote healing.
• Acute Fissures:
  • Conservative management:
    • Sitz baths
    • Fiber supplementation
    • Stool softeners
    • Bulking agents
    • Topical anesthetics Anesthetics Agents that are capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act to induce general anesthesia, in which an unconscious state is achieved, or may act locally to induce numbness or lack of sensation at a targeted site. Anesthesiology: History and Basic Concepts/ steroids Steroids A group of polycyclic compounds closely related biochemically to terpenes. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (sterols), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. Benign Liver Tumors
    • Topical nitroglycerin Nitroglycerin A volatile vasodilator which relieves angina pectoris by stimulating guanylate cyclase and lowering cytosolic calcium. It is also sometimes used for tocolysis and explosives. Nitrates or nifedipine Nifedipine A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers) (to increase local blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure, promote healing, and relieve sphincter spasm)
• Chronic Fissures:
  • First-line Therapy:
    • Topical calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes channel blockers (e.g., diltiazem Diltiazem A benzothiazepine derivative with vasodilating action due to its antagonism of the actions of calcium ion on membrane functions. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers)) are preferred due to fewer side effects.
    • Topical nitrates Nitrates Nitrates are a class of medications that cause systemic vasodilation (veins > arteries) by smooth muscle relaxation. Nitrates are primarily indicated for the treatment of angina, where preferential venodilation causes pooling of blood, decreased preload, and ultimately decreased myocardial O2 demand. Nitrates (e.g., glyceryl trinitrate) are effective but often limited by headaches.
  • Botulinum Toxin Botulinum toxin Toxic proteins produced from the species Clostridium botulinum. The toxins are synthesized as a single peptide chain which is processed into a mature protein consisting of a heavy chain and light chain joined via a disulfide bond. The botulinum toxin light chain is a zinc-dependent protease which is released from the heavy chain upon endocytosis into presynaptic nerve endings. Once inside the cell the botulinum toxin light chain cleaves specific snare proteins which are essential for secretion of acetylcholine by synaptic vesicles. This inhibition of acetylcholine release results in muscular paralysis. Botulism Injection: effective in 67% of cases; typically second-line but can be first-line treatment
  • Surgical options:
    • Lateral Internal Sphincterotomy (LIS):
      • Useful in refractory cases
      • Relieves sphincter spasm → increases blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure and promotes healing
      • Healing rates: ~90-100% (meaning the anal fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes completely closes and resolves after the surgical intervention).
      • Risk of fecal incontinence Fecal incontinence Failure of voluntary control of the anal sphincters, with involuntary passage of feces and flatus. Pediatric Constipation: 8-30%
    • Anal advancement flap (anoplasty)
    • Sphincter dilation: no longer commonly used secondary to high complication rates

Mnemonic

The “Ds” of anal fissures Anal fissures A painful linear tear at the margin of the anus. It appears as a crack or slit in the mucous membrane of the anus and is very painful and difficult to heal. Constipation: 

• Distal to the Dental line
• bleeDing During Defecation; 
• Dull puD en EN Erythema nodosum is an immune-mediated panniculitis (inflammation of the subcutaneous fat) caused by a type IV (delayed-type) hypersensitivity reaction. It commonly manifests in young women as tender, erythematous nodules on the shins. Erythema NodosumD al AL Amyloidosis pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
• Diet low in fiber ( constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation)

Differential Diagnosis

• Anal carcinoma: neoplastic disease in which cancer cells form and grow in the anus. Symptoms include bleeding from the anus, anal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, anal mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast, or itching. Risk factors include older age, infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease such as human papillomavirus Human papillomavirus Human papillomavirus (HPV) is a nonenveloped, circular, double-stranded DNA virus belonging to the Papillomaviridae family. Humans are the only reservoir, and transmission occurs through close skin-to-skin or sexual contact. Human papillomaviruses infect basal epithelial cells and can affect cell-regulatory proteins to result in cell proliferation. Papillomavirus (HPV) ( HPV HPV Human papillomavirus (HPV) is a nonenveloped, circular, double-stranded DNA virus belonging to the Papillomaviridae family. Humans are the only reservoir, and transmission occurs through close skin-to-skin or sexual contact. Human papillomaviruses infect basal epithelial cells and can affect cell-regulatory proteins to result in cell proliferation. Papillomavirus (HPV)), multiple sexual partners, and anal sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria. Anal carcinoma is diagnosed by biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma. Treatment can include surgery, radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma, or chemotherapy Chemotherapy Osteosarcoma. In a chronic or atypical anal fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes, anal carcinoma needs to be ruled out.
• Anal fistula Fistula Abnormal communication most commonly seen between two internal organs, or between an internal organ and the surface of the body. Anal Fistula or abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease: an abnormal connection between the epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium: Histology of the anal canal and another body structure. Anal fistulas often occur due to extension Extension Examination of the Upper Limbs of anal abscesses. Symptoms include anal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways or abnormal discharge/drainage. Management is primarily surgical, with a fistulotomy Fistulotomy Anal Fistula. Anal abscesses produce a tender bulge/ mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast in the anorectal region. In anal fistulas, there is the presence of a palpable fistulous tract.
• Hemorrhoids Hemorrhoids Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Hemorrhoids: enlargement of anal cushions (submucosal vessels) at the distal rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy. Depending on the location of the veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology, hemorrhoids Hemorrhoids Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Hemorrhoids can be internal or external. External hemorrhoids Hemorrhoids Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Hemorrhoids are painful, whereas internal hemorrhoids Hemorrhoids Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Hemorrhoids are painless; both can bleed and appear as a soft rectal mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast on exam. Commonly caused by constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation, and diagnosed on exam. Treatment includes stool softeners, topical hydrocortisone Hydrocortisone The main glucocorticoid secreted by the adrenal cortex. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions. Immunosuppressants, and sitz baths. Additional treatment options are rubber band ligation Band ligation Mallory-Weiss Syndrome (Mallory-Weiss Tear) or surgical removal.  
• Perianal ulcerations: erosions Erosions Corneal Abrasions, Erosion, and Ulcers in the perianal mucosa. Occur secondary to inflammatory bowel disease, most notably Crohn’s disease, infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, and cancer. Symptoms include pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, bleeding, and erosions Erosions Corneal Abrasions, Erosion, and Ulcers in the lining of the mucosa. Treatment is aimed at the causative disease. Perianal ulcerations are differentiated from anal fissures Anal fissures A painful linear tear at the margin of the anus. It appears as a crack or slit in the mucous membrane of the anus and is very painful and difficult to heal. Constipation on physical exam by deeper erosions Erosions Corneal Abrasions, Erosion, and Ulcers in mucosa and evidence of other causative diseases.