Megacolon – the congenital or acquired hypertrophy of all thick gut or its separate part. The clinic of megacolon includes persistent locks, a meteorizm, increase in a stomach, kalovy intoxication, attacks of passing intestinal impassability. The megacolon is diagnosed by means of x-ray methods (a survey X-ray analysis, an irrigoskopiya), endoscopic researches (a rektoromanoskopiya, a kolonoskopiya, a biopsy), manometriya. Treatment of megacolon surgical, consists in a resection of the expanded site of a thick gut.
The megacolon in a proktologiya meets at such diseases as Shagas's disease, a disease of Girshprunga, idiopathic , etc. At megacolon increase in a gleam, a thickening of walls, lengthening of a part or all thick gut is noted. Owing to a pathological hypertrophy there is a development of a focal inflammation and atrophy mucous, violation of a passage and evacuation of contents of a large intestine. At the megekolena of change concern a sigmovidny gut more often: there is its rasshiyereniye (megasigma) in combination with simultaneous lengthening (megadolikhosigm).
Classification of forms of megacolon
The megacolon can have the congenital or acquired origin. The congenital megacolon (a disease of Girshprunga) is characterized agangliozy - lack of nervous textures in walls of rektosigmoidalny department of a thick gut. The Deinnervirovanny site of a gut is narrowed, deprived of a vermicular movement and is an organic obstacle for passing of kalovy masses. Except a disease of Girshprunga, the congenital megacolon can be caused by the idiopathic reasons (chronic locks of any origin) or existence of a mechanical obstacle in disteel departments of a large intestine (a stenosis of a rectum, a svishchevy form of an atresia of back pass, etc.). The clinic of congenital megacolon develops already in the early childhood.
Formation of the acquired megacolon can be connected with secondary changes of a thick gut as a result of tumors, injuries, fistulas, excesses, colitis with the subsequent cicatricial change mucous and so forth Besides, as the reason of the acquired megacolon defeat parasympathetic owing to B1 hypovitaminosis can act. On an etiologichesky factor allocate various forms of megacolon: aganglionarny (disease of Girshprunga), idiopathic (35%), obstructive (8-10%), psychogenic (3-5%), endocrine (1%), toxic (1-2%), neurogenetic (1%) megacolon.
On localization and extent of the site of a hypertrophy distinguish a rectal, rektosigmoidalny, segmentary, subtotal and total form of megacolon. At a rectal form of a disease the promezhnostny department of a rectum is surprised, its ampulyarny and nadampulyarny speak rapidly. The Rektosigmoidalny form of megacolon is characterized partial or checkmate of a sigmovidny gut. At a segmentary form of megacolon of change can be localized in one segment of rektosigmoidny transition or a sigmovidny gut or two segments between which the site of not changed gut is located. The subtotal option of megacolon includes defeat descending and parts of obodochny department of a thick gut; at a total form all thick gut is surprised.
The clinical current of megacolon can be compensated (chronic), subcompensated (subsharp) and dekompensirovanny (heavy).
Reasons and pathogenesis of megacolon
The congenital megacolon is caused by absence or deficiency of peripheral receptors, violation of conductivity on nervous ways which develop as a result of violation of migration of neurons in the course of an embryogenesis. As the reasons of the acquired megacolon toxic defeats of nervous textures in a wall of a thick gut, TsNS dysfunction at Parkinson's disease can act, injuries, tumors, fistulas, cicatricial narrowings, medicinal locks, collagenases (a sklerodermiya, etc.), a hypothyroidism, intestines and so forth. These factors cause violation of motive function of a thick gut on this or that extent and organic narrowing of its gleam.
Violation of an innervation or mechanical obstacles complicate a passage of kalovy masses by the narrowed part of a gut, causing sharp expansion and increase in the departments located above. Activization of a vermicular movement and a hypertrophy of the top departments is compensatory and is formed for advance of intestinal contents through an aganglionarny or stenozirovanny zone. Further in expanded department there is a death of hypertrophied muscle fibers and their replacement with connecting fabric that is followed by an atoniya of the changed department of a gut. Advance of intestinal contents is slowed down, there are long locks (the chair is absent on 5-7, sometimes 30 days), desires on defecation are oppressed, there is an absorption of slags, development of dysbacteriosis and kalovy intoxication. Similar processes at megacolon inevitably are followed by an arrest of development of the child or sharp decrease in working ability of adults.
Weight of a current and feature of clinic of megacolon are directly connected with the extent of the struck department and compensatory opportunities of an organism. At congenital megacolon from the first days or months of life there is no independent chair, the meteorizm develops, the stomach circle increases, chronic kalovy intoxication accrues. Periodically there is vomiting with bile impurity. Depletion of intestines occurs only after introduction of an exhaust tube, performance of a cleaning or siphon enema. The putrefactive smell, content of slime, blood, particles of undigested food is characteristic of excrements. At children with megacolon exhaustion, lag of physical development, anemia is observed.
The progressing chronic locks and swelling of intestines at megacolon lead to thinning and flabbiness of a belly wall, formation, so-called, "a frog stomach". Through a forward belly wall it is possible to observe a vermicular movement in the inflated intestines loops. Expansion and inflation of a thick gut at megacolon is followed by high standing of a dome of a diaphragm, reduction of a respiratory excursion of lungs, shift of bodies of a sredosteniye, change of the size and a shape of a thorax (a barrel-shaped thorax). On this background cyanosis, short wind, tachycardia develops, changes on the electrocardiogram are registered, conditions for recurrent pneumonia and bronchitis are created.
As frequent complications of megacolon serve dysbacteriosis and development of sharp intestinal impassability. At dysbacteriosis in intestines the secondary inflammation develops, there is an ulceration mucous that is shown by "paradoxical" ponosa. Development of obturatsionny impassability of intestines is followed by unrestrained vomiting and belly-aches, in hard cases – a perforation of a thick gut and kalovy peritonitis. At a zavorota or an uzloobrazovaniye of a gut there can be a strangulyatsionny intestinal impassability.
Diagnostics of megacolon
At diagnostics of megacolon data of clinical symptomatology, objective survey, results of x-ray and endoscopic diagnostics, laboratory analyses are considered (a calla on dysbacteriosis, koprogramma, histology). At the general survey the increased, asymmetric stomach pays attention. At an intestines loop palpation, filled with kalovy masses, have a pasty consistence, and in case of kalovy stones – dense. At megacolon the symptom of "clay" is noted - pressing by fingers on a forward belly wall leaves on it marks of a vdavleniye.
The survey X-ray analysis of an abdominal cavity at megacolon reveals the inflated and expanded intestinal loops of a thick gut, highly located diaphragm dome. The X-ray contrast irrigoskopiya allows to define an aganglionarny zone – the site of narrowing of a thick gut with expansion of its overlying departments, a smoothness of their contours, lack of a skladchatost and . At the same time expansion of a straight line (), sigmovidny (megasigma) or all obodochny gut can prevail (megacolon). By means of a rektoromanoskopiya and a kolonoskopiya the large intestine is examined, the transanal endoscopic biopsy is carried out. Absence in a bioptata of a muscular cover of a rectum of nervous cages of an auerbakhovsky texture confirms the diagnosis of a disease of Girshprunga.
Carrying out an anorektalny manometriya at megacolon is necessary for assessment of a rectal reflex and differentiation of the congenital and acquired megacolon. Safety of a reflex testifies to not damage and absence of a disease of Girshprunga. Differential diagnostics at megacolon is carried out with the tumors of a thick gut, chronic colitis, a syndrome of the angry intestines, a divertikulyarny disease, habitual locks caused by anal cracks.
Treatment of megacolon
Medical tactics depends on a clinical current and a form of megacolon. At the compensated and subcompensated current, and also inorganic forms of megacolon conservative approach is undertaken. Therapy of megacolon includes a diet with the high content of cellulose, an enema (cleaning, vaseline, hypertensive, siphon), massage of a stomach, purpose of the bacterial medicines normalizing intestinal microflora, fermental medicines, modulators of motility of a thick gut, carrying out LFK and electrostimulation of a rectum.
At a disease of Girshprunga expeditious treatment – performance of a resection of an aganglionarny zone and expanded part of a thick gut which is carried out at the age of 2-3 years is required. In case of obstructive megacolon the emergency imposing of a kolostoma and preparation for radical intervention is required.
The volume of a resection of a thick gut at megacolon is defined by the extent of defeat and can include a forward resection of a rectum, a bryushnoanalny resection with bringing down of an obodochny gut, a rektosigmoidektomiya with imposing of a kolorektalny anastomoz, a subtotal resection of a thick gut with formation of an ileorektalny anastomoz, etc. During radical intervention or after it the separate stage makes closing of a kolostoma.
Treatment of other forms of megacolon consists in elimination of the reasons – mechanical obstacles (a svishchevy atresia of back pass, a cicatricial stenosis, solderings), chronic locks, hypovitaminosis, intestines inflammations (colitis, a rektosigmoidit). The further forecast is defined by a form and the reasons of megacolon, correctness of volume and a method of operation.