Sentinel Hemorrhoid: what it is, causes, symptoms and treatments

• The sentinel haemorrhoid has nothing to do with haemorrhoids, but is a complication associated with a chronic anal fissure.
• In many cases haemorrhoids are diagnosed when in fact it is a sentinel haemorrhoid, which can lead to problems.
• To solve a sentinel haemorrhoid, the only option is an anal fissure operation by means of a lateral internal sphincterotomy.

A sentinel haemorrhoid is a small, papilla-like lesion that grows in the anal canal in reaction to an injury to the anus, usually accompanying a chronic anal fissure. 

The sentinel haemorrhoid is not a disease in itself, but a sign or symptom of anal fissure. Consequently, both symptoms and treatment overlap with those of anal fissure

The presence of a sentinel haemorrhoid alerts the doctor that the patient may have an anal fissure. A sentinel haemorrhoid has nothing to do with conventional haemorrhoids, as it is a skin fold and does not contain dilated blood vessels, as is the case with varicose dilatation of the haemorrhoidal veins that causes what we know as piles. 

Often, patients with anal fissure are falsely diagnosed with haemorrhoids because of the presence of a sentinel haemorrhoid and are treated for it. This is the first problem.

Conventional haemorrhoid ointments do not help with anal fissures and can actually worsen the problem. Sitz baths with cold water relieve the symptoms of haemorrhoids while local heat or sitz baths with warm water improve the muscle contraction of the internal anal sphincter in the case of an anal fissure.

Conventional haemorrhoid ointments do not help with anal fissures and can actually worsen the problem. 

Sitz baths with cold water relieve the symptoms of haemorrhoids while local heat or sitz baths with warm water improve the muscle contraction of the internal anal sphincter in the case of an anal fissure.

The main cause of the appearance of a sentinel haemorrhoid is a chronic anal fissure. Chronic anal fissure is characterised by more than 4-8 weeks of evolution; it is usually deep to the internal anal sphincter, usually accompanied by an indurated skin fold at the distal end (sentinel haemorrhoid) and a hypertrophic papilla at the proximal edge (Lane's polyp). 

Over time, the skin at the distal end of the fissure becomes oedematous and a fibrous skin flap forms, known as a 'sentinel haemorrhoid'; the term 'sentinel' is used because it marks the site of the fissure.

This pathology is a very painful entity, so great care must be taken to avoid hurting the patient during the diagnostic examination. For physical examination, a slight separation of the lateral walls of the anus may be sufficient to expose the distal end of the fissure. 

Digital rectal examination is not always indicated and if the diagnosis is clear, it can be omitted. In case of doubt, the application of a topical anaesthetic is necessary to perform a digital rectal examination and clarify the diagnosis.

Chronic anal fissure usually consists of a triad (Brodie's triad), which includes a skin flap or "sentinel haemorrhoid", an ulcer that usually exposes the internal anal sphincter fibres and a hypertrophic anal papilla, which are glands in the area that help during defecation.

The symptoms of the sentinel haemorrhoid are really the symptoms of an anal fissure, since, as we have already mentioned, the sentinel haemorrhoid is the consequence of an anal fissure.

The main symptom of a fissure is pain. It is an intense, cutting pain, "as if cutting with a knife", clearly associated with the passage of stool during bowel movements, which persists for a variable length of time after the bowel movement, ranging from minutes to hours. 

There may also be bleeding, itching or stinging and inflammation of the base of the fissure, which is often mistaken for a haemorrhoid, although in this case it is actually a sentinel haemorrhoid, indicating the presence of an anal fissure.

Another symptom is "bright red" bleeding not mixed with stool that soaks through toilet paper. Staining of mucus or yellowish mucus (pus) is also a sign that appears in most cases of sentinel haemorrhoids.

The formation of an anal fissure leads to the establishment of a "vicious circle" that hinders or prevents its healing: the fissure makes defecation painful; the pain causes a spasm of the internal anal sphincter; the spasm of the internal sphincter causes an alteration of the vascularisation of the anal region that hinders the healing of the fissure, thus favouring the persistence of the "vicious circle". Therefore, the best option for a chronic anal fissure is surgery to repair it.

The treatment of the sentinel haemorrhoid coincides with the treatment of chronic anal fissure. Treatment of an acute anal fissure is usually conservative, whereas in the case of chronic anal fissure with the so-called sentinel haemorrhoid, treatment is surgical in almost all cases.

The exposure of transverse fibres of the internal anal sphincter, the appearance of hypertrophic anal papilla and the presence of the "sentinel" skin flap or "sentinel haemorrhoid" indicate the chronicity of the disease. 

Anal fissure, in which a "vicious circle" has been established and has failed conservative medical treatment and become chronic, is treated by surgery with a lateral internal sphincterotomy as the treatment of choice:

• The operation consists of a controlled section of the internal anal sphincter, which eliminates the hypertonia of the sphincter, eliminating pain and allowing the fissure to heal within a few days.
• The surgeon first dilates the anus using a bivalve anal retractor to expose the fissure to the specialist surgeon.
• Once the surgeon has a complete view of the fissure, he locates the intersphincteric groove that marks the division between the internal portion of the anal sphincter and its external portion.
• A minimal incision is made with a scalpel or electric scalpel of no more than 2-4 mm in the region of the internal lateral sphincter and then sutured.
• This surgical technique has gained an advantage over others because of its short hospital stay (1-2 days), immediate improvement of symptoms, a small number of complications and a recurrence of the fissure in less than 8 months in less than 2% of cases.