Megacolon - Congenital or acquired hypertrophy of the entire colon or its separate parts. megacolon Clinic include persistent constipation, flatulence, increased abdominal fecal intoxication, transient bouts of intestinal obstruction. Megacolon is diagnosed by X-ray methods (survey radiography, barium enema), endoscopy (sigmoidoscopy, colonoscopy, biopsy), manometry. Megacolon surgical treatment, is expanded portion resection of the colon.
proctology occurs in such diseases as Chagas disease, Hirschsprung's disease, idiopathic megadolihokolon and others. When there is an increase megacolon lumen wall thickening, lengthening of part or all of the colon. As a result of pathological hypertrophy is the development of focal inflammation and atrophy of the mucosa, disturbance of a passage and the evacuation of the colon contents. When megekolone changes often relate to the sigmoid colon: it happens the SAN (megasigmoid) in combination with a simultaneous lengthening (megadolihosigma).
Hirschsprung's disease) characterized agangliozom - lack of nerve plexus within the walls of the colon rektosigmoidalnogo department. Deinnervirovanny colon narrowed portion, devoid of peristalsis and an organic obstacle to the passage of stool. In addition to Hirschsprung's disease, congenital megacolon may be due to idiopathic causes (chronic constipation of any origin) or the presence of mechanical obstruction in the distal colon (rectum stenosis, fistula forms anus atresia and others.). Clinic congenital megacolon develops in early childhood.
Formation of acquired megacolon may be due to secondary changes as a result of colon tumors, injuries, fistulas, kinks, colitis, followed by scarring of mucous, and so on. In addition, the cause of acquired megacolon may be a loss of parasympathetic ganglia due to hypovitaminosis B1.
According to various etiological factor isolated form megacolon: aganglionarny (Hirschsprung's disease), idiopathic (35%), obstructive (8-10%), psychogenic (3-5%), endocrine (1%), toxic (1.2%) neurogenic (1%) megacolon.
According to the location and extent of hypertrophy of the rectal area are distinguished, rektosigmoidalnuyu, segmental, subtotal and total form of megacolon. When the rectal form of the disease is affected perineal rectum department and its ampullar nadampulyarnaya part. Rektosigmoidalnaya form of megacolon is characterized by partial or total lesion of the sigmoid colon. In the form of segmental megacolon changes can be localized in one segment of rectosigmoid junction or sigmoid colon, or two segments, between which a portion of the intestine intact. Subtotal option involves megacolon defeat of the colon and the descending colon department; at total shape it affected the entire colon.
The clinical course may be compensated megacolon (chronic) subcompensated (subacute) and decompensated (heavy).
Parkinson's disease, trauma, tumors, fistulas, scar contraction, constipation drug, collagen diseases (scleroderma, etc.), hypothyroidism, amyloidosis of the intestine and so forth. These factors cause a violation of the motor function of the colon in one or another over and organic narrowing of its lumen.
Violation of innervation or mechanical barriers impede the passage of feces on narrowed part of the intestine, causing a sharp increase in the expansion and departments located above. Activation of peristalsis and hypertrophy of the top departments of a compensatory and formed for the promotion of intestinal contents through aganglionarnuyu or stenotic area. Later in the extended section there is a destruction of hypertrophied muscle fibers and their replacement by connective tissue, which is accompanied by atony altered bowel department. Slows the promotion of intestinal contents, there are long-term constipation (no stools at 5-7 sometimes 30 days), inhibits the urge to defecate, are absorbed toxins, dysbiosis development and fecal intoxication. Similar processes in megacolon inevitably accompanied by delayed development of the child or a sharp decline of adult disability.
chronic constipation and flatulence with megacolon lead to thinning and sagging abdominal wall, forming the so-called "frog stomach". Through the abdominal wall can be seen in the swollen bowel motility hinges.
The expansion and swelling of the colon if megacolon associated with high standing dome of the diaphragm, a decrease in lung respiratory excursions, offset mediastinal organs, change the size and shape of the chest (barrel chest). Against this background develop cyanosis, dyspnea, tachycardia, recorded changes in the electrocardiogram, the conditions for recurrent pneumonia and bronchitis.
Frequent complications megacolon are bacteria overgrowth and development of acute intestinal obstruction. When dysbacteriosis in the gut develops secondary inflammation, there is ulceration of the mucous that is shown "paradoxical" diarrhea. The development of obstructive ileus is accompanied by uncontrollable vomiting and abdominal pain, in severe cases - perforation of the colon and fecal peritonitis. When you roll the nodulation or bowel may occur strangulation intestinal obstruction.
fecal bacteria overgrowth, coprogram, histology).
In the general survey draws attention to an enlarged, asymmetric stomach. On palpation of the intestinal loops filled with feces, have testovatoy consistency, and in the case of fecal stones - tight. When megacolon marked symptom of "clay" - finger pressure on the anterior abdominal wall to let any traces of depressions.
Survey abdominal radiography reveals swollen with megacolon and colon extended intestinal loop, located high dome of the diaphragm. Radiopaque barium enema to determine aganglionarnuyu area - site of narrowing of the colon with the expansion of its overlying departments, flattening their contours, no folding and haustrum. This may dominate the expansion line (megarektum), sigmoid (megasigmoid) or the entire colon (megacolon).
With sigmoidoscopy and colonoscopy are examined colon, performed transanal endoscopic biopsy. Lack of muscle biopsy of the rectum sheath of nerve cells auerbahovskogo plexus confirms the diagnosis of Hirschsprung's disease.
Carrying anorectal manometry with megacolon is necessary to assess rectal reflex and differentiation of congenital and acquired megacolon. Safety reflex indicates no intact ganglia and Hirschsprung's disease.
Differential diagnosis for megacolon held from colon tumors, chronic colitis, irritable bowel syndrome, diverticular disease, habitual constipation, caused by anal fissures.
Exercise therapy and electrical stimulation of the rectum.
In Hirschsprung's disease require surgery - resection aganglionarnoy zone and the extended part of the colon, which takes place at the age of 2-3 years. In the case of obstructive megacolon required emergency colostomy and preparation for radical intervention.
Volume colon resection for megacolon is determined by the length of lesion and may include anterior resection of the rectum, bryushnoanalnuyu resection with bringing down the colon, proctosigmoidectomy overlay colorectal anastomosis, subtotal resection of the colon with the formation ileorektalnogo anastomosis and others. In the course of radical intervention or after a separate step performed a colostomy closure.
Treatment of other forms of megacolon is to eliminate the causes - mechanical obstacles (fistula atresia of the anus, cicatricial stenosis, adhesions), chronic constipation, vitamin deficiencies, intestinal inflammation (colitis rektosigmoidita).
Further prognosis determined by the form and causes of megacolon, the correctness of the amount and method of operation.