ANAL AND PERIANAL SUPPURATIONS (INFECTIONS)

Classified as perianal abscesses, phlegmones and fistulas, such disorders are actually evolutive stages of the same condition.

Perianal abscesses and fistula may be deemed as possible developing fistula while fistula may also be deemed as sequels of improperly or insufficiently treated abscesses and phlegmone.

Some of these entities the surgical therapy of which is crucial and mandatory may also be approached with no significant risks under local anesthesia, in ambulatory conditions especially whenever radiofrequency ablation is part of the proctologic therapeutic arsenal.

The occurrence of abscesses in this region is favored by local sepsis as well as by the impressive amount of germ admission gateways (solutions of continuity induced by defecation, improper hygiene, scratching, etc.) and by the possible existence of favoring comorbidities (CROHN disease).

How to perianal abscesses and phlegmone appear

It is generally accepted that all anal suppurations begin with crypts within the anal duct, folds of the mucosa shaped as “bird nests” in which there is the opening via papilla of mucus secreting glands known as the glands of Hermann and Desfosses, the glandular body of which lies within the depth of the anal duct.

These glands, due to their secreted mucus, are involved in protecting and lubricating the anal duct against the traumas induced by the passage of the feces.

The anal crypts may get infected in either one of the following three ways – either directly, via germ penetration (enterocolitis), or indirectly, due to injuries of the anal mucosa (constipation, foreign bodies, parasites), or, lastly, medically induced as a result of medical techniques (sclerotherapy, infiltrations).

Some pathological conditions favor the crypt infection: the co-existence of hemorrhoids altering the regional anatomy by opening the crypts (which are naturally virtual), congenital alterations, etc.

Once initiated the crypt infection propagates towards the Hermann and Desfosses glandular bodies, the channels of which open within the crypts; the bodies of these glands is within the depth of the sphincter system and sub-mucosa (hence within the wall of the anal duct), and this is why the infection is located in these region and later on propagates towards the subcutaneous tissue surrounding the anal duct, forming the trajectories of the future fistula.

The staged evolution may be classified as follows:
• Primary stage – formation;
• Extension stage;
• In-tegument opening stage.

In the end, if untreated / improperly treated, the collection may evacuate (never completely) within one or several skin openings, generating a perianal fistula.

Other modalities of inducing perianal suppurations are represented by:
- infections of the perianal skin (for instance, the abscess of sudoripary glands);
- infections induced by haemorrhoidal lesions (suppurated thrombosis, infected marisca);
- secondary infections of chronic anal fissures;
- hematogenic dissemination (via blood).

Perianal abscess and phlegmon

The perianal abscess is a pyogenetic collection within the depth of the anal duct wall located either towards the edge of the anus or between the muscular fascicles of the anal sphincters.

The phlegmon is an extension of the abscess towards the anus-neighboring anatomical regions, affecting either one or all of these regions.

The symptoms are mainly represented by pain and infectious syndrome (fever, chills, altered general condition, etc.). The fistula formation stage diminishes the symptoms as the fistula trajectory becomes chronic and opens towards the exterior of the tegument.

Perianal Fistula

This is not really a disorder in itself, but only a sequel of an improperly or lately treated perianal abscess or phlegmon (most often the patient seeks professional advice from the proctologist or surgeon too late).

How do perianal fistulas occur ?

There are multiple causes leading the formation of perianal fistulas:
- fistula secondary to nespecifice anal and perianal suppurations;
- fistula secondary to surgically ignored suppurations (natural evolution);
- fistula secondary to improperly treated suppurations (incompletely treated);
- tuberculosis fistula;
- fistula encountered in ulcerous colitis;
- fistula secondary to Crohn disease;
- other causes: abscessed cancers, post-operator recurrent fistula, benign limphogranulomatosis.

Most of them are the fistula secondary to surgically ignored or improperly treated suppurations.

The perianal fistula may be either simple (one trajectory with two openings), complex (several trajectories and orifices) and complicated (whenever they open in the neighboring organs).

The perianal fistula are characterized by intermittent pyogenetic secretion, continuous or intermittent pain, tenesma (fake defecation sensation) and minor bleedings in the context of the palpation of an indurate perianal region and (not always!) of viewing the skin opening. The internal orifice needs to be located with the anuscope, in order to assess the trajectory and length of the fistula.