Megacolon is the dilatation 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 congenital disease of the baby, known as Hirschsprung's disease, or can be acquired throughout life due to Chagas disease, for example.
Another form of megacolon is an 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 like constipation that worsens over time, vomiting, bloating and abdominal pain appear. Although it has no cure, megacolon can be treated according to its cause, and consists of relieving symptoms, using laxatives and intestinal lavage, or performing surgery to remove the affected part of the intestine, correcting more definitive changes.
Signs and symptoms
Due to impairment of bowel movement capacity, the signs and symptoms of megacolon include:
- Intestinal constipation, or constipation, worsens over time, and can go as far as stool and gas elimination altogether;
- Need to use laxatives or intestinal lavage to evacuate;
- Abdominal swelling and discomfort ;
- Nausea and vomiting, which can be serious and even eliminate the contents of the stool.
The intensity of these symptoms varies according to the severity of the disease. Therefore, the symptoms may be noticed in the first days of life, as in the case of congenital megacolon, or they can be evidenced after months or years of onset of the disease, as in case of acquired megacolon, since the disease progresses slowly.
Main causes
Megacolon can occur from a variety of causes, which can arise from birth or are acquired over a lifetime. The most common causes are:
1. Congenital Megacolon
This disorder, known as Hirschsprung's disease, is a disease that is already 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 the symptoms.
This disease is rare, caused by genetic changes, and the symptoms may already arise from the first few hours or days after birth. However, if the changes and symptoms are mild, it may take weeks or months to properly identify the disease, and in these cases, it is common for the baby to have a growth retardation due to a lower absorption capacity of the nutrients foods.
How to confirm : the diagnosis of the congenital megacolon is made by the observation of the child's symptoms by the doctor, physical examination, besides the request of exams such as x-ray of the abdomen, opaque enema, anorectal manometry and rectal biopsy, which confirm the disease .
How to treat : Initially, temporary colostomy surgery can be done to allow the baby to excrete the stool through a small pouch that is stuck to the belly. Thereafter, 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 megacolon acquired is Chagas Disease, a condition known as chagasic megacolon, which occurs due to intestinal nerve endings caused by infection by the protozoan Trypanosoma cruzi transmitted by the bite of the insect barber.
Other causes of dilatation and stopping of bowel 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 potassium, sodium, and chlorine deficiencies;
- Systemic diseases such as scleroderma or amyloidosis;
- Intestinal scars, caused by radiotherapy or intestinal ischemia;
- Chronic use of constipating drugs, such as anti-cholinergic and anti-spasmodic drugs, or laxatives;
Megacolon may also be of the functional type, where the exact cause is not known, but is probably caused by chronic and severe intestinal constipation that is not properly treated and worsens over time.
How to confirm : To diagnose acquired megacolon, an evaluation of the gastroenterologist or coloproctologist, who will analyze the clinical history and the physical examination, and to request tests such as x-ray of the abdomen, opaque enema and, in cases of doubts about the cause of the disease, intestinal biopsy, allowing confirmation.
How to treat : The treatment is done to allow the elimination of feces and gases through the intestine, and can initially be done with the help of laxatives such as Lactulose or Bisacodyl, for example, and intestinal lavage, however, when the symptoms are intense and with little improvement, surgery is scheduled for removal of the affected part of the intestine by the coloproctologist.
3. Toxic megacolon
Toxic megacolon is an acute and severe complication of some type of intestinal inflammation, especially in cases of Crohn's disease or ulcerative colitis, although it may be associated with any type of colitis, due to intestinal twisting, diverticulitis, intestinal ischemia or obstruction due to colon cancer.
During a picture of toxic megacolon, there is an intense dilatation of the intestine that has fast, serious evolution and that causes risk of death, due to the intense inflammation that happens in the organism. In addition, there are signs and symptoms such as fever over 38.5 ° C, heart rate above 120 beats per minute, excess white blood cells in the bloodstream, anemia, dehydration, mental confusion, altered blood electrolytes and blood pressure drop.
How to confirm : The confirmation of toxic megacolon is made by medical evaluation through analysis of the abdomen x-ray, which shows an intestinal dilatation greater than 6 cm wide, physical examination and clinical signs and symptoms.
How to treat : Treatment is directed to symptom control, replacement of blood electrolytes, use of antibiotics and other drugs to decrease intestinal inflammation such as corticosteroids and anti-inflammatories. However, if the condition continues to worsen, full bowel removal surgery may be indicated as a way to eliminate the inflammation focus and allow recovery of the affected person.
