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The megacolon is the dilation of the large intestine, accompanied by difficulty in eliminating feces and gases, caused by lesions in the nerve endings of the intestine. It can be a consequence of a baby's congenital disease, known as Hirschsprung's disease, or it can be acquired throughout life, due to Chagas disease, for example.
Another form of megacolon is due to acute and severe intestinal inflammation, called toxic megacolon, which is usually developed by people with inflammatory bowel disease, causing intense bowel dilation, fever, rapid heartbeat and risk of death.
With the loss of contractions and bowel movements in this disease, signs and symptoms appear, such as constipation that worsens over time, vomiting, bloating and abdominal pain. Despite having no cure, the megacolon can be treated according to its cause, and consists of the relief of symptoms, with the use of laxatives and intestinal washes, or in the performance of surgery to remove the affected part of the intestine, correcting in a way more definitive changes.
Main signs and symptoms
Due to impaired bowel movement capacity, megacolon signs and symptoms include:
- Intestinal constipation, or constipation, which worsens over time, and can even stop stool and gas elimination;
- Need to use laxatives or intestinal lavage to evacuate;
- Bloating and abdominal discomfort;
- Nausea and vomiting, which can be severe and even eliminate the contents of the stool.
The intensity of these symptoms varies according to the severity of the disease, so the symptoms can be noticed already in the first days of life, as in the case of congenital megacolon, or can be seen after months or years of onset, as in case of acquired megacolon, as the disease progresses slowly.
Main causes
Megacolon can happen for several causes, which can arise from birth or be acquired throughout life. The most common causes are:
1. Congenital megacolon
This alteration, known as Hirschsprung's disease, is a disease that is born with the baby, due to a deficiency or absence of nerve fibers in the intestine, which prevents its proper functioning for the elimination of feces, which accumulate and cause symptoms.
This disease is rare, caused by genetic changes, and the symptoms can already appear from the first hours or days after birth. However, if the changes and symptoms are mild, it may take weeks or months to correctly identify the disease and, in these cases, it is common for the baby to have a delay in growth, due to a lesser absorption capacity of nutrients from foods.
How to confirm: the diagnosis of congenital megacolon is made by observing the child's symptoms by the doctor, performing a physical examination, in addition to requesting tests such as an x-ray of the abdomen, an opaque enema, anorectal manometry and rectal biopsy, which allow the disease to be confirmed. .
How to treat: Initially, a temporary colostomy surgery can be performed to allow the baby to pass stool through a small bag that is attached to the belly. Then, a definitive surgery is scheduled, around 10-11 months of age, with removal of the impaired intestinal part and restructuring of the intestinal transit.
2. Megacolon acquired
The main cause and acquired megacolon is Chagas Disease, a situation known as chagasic megacolon, which occurs due to lesions in the intestinal nerve endings caused by infection with the protozoanTrypanosoma cruzi, transmitted by the bite of the insect barber.
Other causes of dilation and stopped intestinal functioning that are acquired throughout life are:
- Cerebral palsy;
- Diabetic neuropathy;
- Spinal cord injuries;
- Endocrinological diseases such as hypothyroidism, pheochromocytoma or porphyria;
- Changes in blood electrolytes, such as deficiencies in potassium, sodium and chlorine;
- Systemic diseases such as scleroderma or amyloidosis;
- Intestinal scars, caused by radiotherapy or intestinal ischemia;
- Chronic use of constipating drugs, such as anticholinergics and anti-spasmodics, or laxatives;
The megacolon can also be of the functional type, in which the exact cause is not known, but which probably originates due to a chronic, severe intestinal constipation that is not properly treated and worsens over time.
How to confirm: in order to diagnose the acquired megacolon, an evaluation by the gastroenterologist or coloproctologist is necessary, who will analyze the clinical history and physical examination, and order tests such as an x-ray of the abdomen, an opaque enema and, in cases of doubt as to the cause intestinal biopsy, allowing confirmation.
How to treat: the treatment is done to allow the elimination of feces and gases by the intestine, and can initially be done with the help of laxatives, such as Lactulose or Bisacodyl, for example, and intestinal washes, however, when the symptoms are intense and with little improvement, a surgery to remove the affected part of the intestine is scheduled by the coloproctologist.
3. Toxic megacolon
Toxic megacolon is an acute and severe complication of some type of intestinal inflammation, mainly due to Crohn's disease or ulcerative colitis, although it can be associated with any type of colitis, whether due to an intestinal torsion, diverticulitis, intestinal ischemia or a colon cancer obstruction.
During a picture of toxic megacolon, there is an intense dilation of the intestine that has a fast, severe evolution and that causes death risk, due to the intense inflammation that happens in the organism. In addition, signs and symptoms appear, such as fever above 38.5ºC, heart rate above 120 beats per minute, excess of white blood cells in the bloodstream, anemia, dehydration, mental confusion, alteration of blood electrolytes and drop in blood pressure.
How to confirm: the confirmation of the toxic megacolon is made by medical evaluation through the analysis of the abdomen x-ray, which shows an intestinal dilation greater than 6 cm in width, physical examination and clinical signs and symptoms.
How to treat: The treatment is aimed at controlling symptoms, replacing blood electrolytes, using antibiotics and other medications to reduce intestinal inflammation, such as corticosteroids and anti-inflammatories. However, if the disease continues to worsen, surgery for complete removal of the large intestine may be indicated as a way to eliminate the focus of inflammation and allow the affected person to recover.
Created by: Tua Saúde Editorial Team