Introduction:
One of the many body parts a human has is the large intestine. It is also called the colon medically. Although the colon has numerous important bodily functions, certain conditions can affect the colon and cause it to work badly. One such condition is a megacolon. As the name suggests, a bigger-sized colon than usual is what it means. This condition could occur due to many reasons but not due to obstruction. There are many variations pertaining to this condition based on the cause, how long it has been present, the damage it causes, and so on. Read further to know it all.
What Is a Megacolon?
Abnormal expansion (dilation) of the colon due to reasons other than obstruction is called a megacolon. Though not a serious condition initially, it can become a serious life-threatening condition if left untreated. The colon or the large intestine does not have a standard diameter throughout; its diameter varies depending upon the part of the colon (cecum, ascending, transverse, descending, and sigmoid). The standard measurement for it to fall under a megacolon is a diameter of more than 6.5 cm at the sigmoid region and more than 8 cm at the ascending colon.
What Are the Types of Megacolon?
Megacolon is classified as;
- Acute Megacolon - It is a temporarily occurring, non-toxic megacolon in which no inflammation is noted. It is also called the Ogilvie syndrome. Acute megacolon can result from damage to the autonomic nervous system, infections, and certain lifestyle habits, and it is always an acquired condition (not present since birth).
- Toxic Megacolon - It is an acute type of megacolon that presents with inflammation. It is a serious and life-threatening condition that starts with irritation and infection in the large intestine and progresses to systemic toxicity (failure of various body organs).
- Chronic Megacolon - It can be either an acquired or a congenital condition resulting from malfunctioning of the colon's neurological and muscular activity, usually from birth.
What Could Cause a Megacolon?
Though the exact cause of megacolon still stands a query, many factors could be the possible causes of this condition. The cause varies with the type of megacolon.
1) Infections: Infections caused by certain microorganisms like viruses, bacteria, and parasites are the most common cause of megacolon. The common organisms responsible for megacolon-causing infections include Clostridioides difficile, Salmonella, Campylobacter, etc. These infections lead to acute or toxic megacolon.
2) Certain Medications: Megacolon might also appear due to certain adverse effects that result from taking a drug. The common drugs that could cause megacolon include, Loperamide, Risperidone, Clozapine, etc. This is an uncommon cause and is usually acute.
3) Underlying Diseases:
- Inflammatory bowel diseases like ulcerative colitis and Crohn's disease are also the most common causes of megacolon. These conditions inflame the large intestine and expand it, resulting in toxic megacolon.
- Other systemic diseases like hypothyroidism, muscle dystrophies, lupus erythematosus (an autoimmune disease in which the body's immune system attacks its own cells), and neurological diseases like Parkinson's disease, diabetic neuropathy, etc., could cause megacolon.
- Acquired megacolon can occur in children due to the child's refusal to defecate as a result of certain emotional disturbances such as anger toward parents, lack of toilet training, or faulty toilet training by the parent.
4) Congenital Megacolon:
- Lack of nerve fibers in the end part of the large intestine results in congenital megacolon.
- This compromises the colon's normal function, causing improper peristalsis (continuous contractions of the muscles to push the digested food through the digestive tract), resulting in stagnation of the stomach contents.
- While the intestine tries to push down the stagnated contents further, there is inflammation and enlargement of the colon. Congenital megacolon is also named Hirschsprung's disease.
5) Other causes: Megacolon can also result from long-term constipation, electrolyte or fluid imbalance in the body, as a complication of certain surgeries and a rare complication in pregnant women.
What Are the Symptoms of Megacolon?
The commonly occurring symptoms of megacolon include;
- Stomach pain and tenderness.
- Bloating.
- Constipation.
When there is inflammation, that is, in toxic megacolon; the following symptoms occur in addition to the common symptoms;
- Fever.
- Swollen abdomen.
- Continuous diarrhea. It can even involve blood.
- Feeling faint and dizzy due to continuous diarrhea.
- Rapid heartbeat.
- Painful defecation.
- Shock (a life-threatening condition in which any type of infection in the body rapidly decreases blood pressure).
How Is Megacolon Diagnosed?
Other than history taking and physical examination, the doctors advise getting,
- CBC (complete blood count).
- Blood electrolytes.
Megacolon can be ruled out by
- X-rays.
- CT (computed tomography) scan.
- Colonoscopy (In cases when the CT is not clear).
Colonoscopy is risky to be performed in patients with toxic megacolon as perforation could occur.
How Is Megacolon Treated?
Treatment for megacolon starts with identifying the cause and the type of megacolon. Following this, the mode of treatment is decided accordingly.
- In the case of acute megacolon, the first step is to rule out if inflammation is present or not; if no inflammation is noted, then a nasogastric tube (food tube that is inserted through the nose and the throat into the stomach) is placed after asking the patient to stop any food (body solid and liquid diet). Following this, a Neostigmine bromide tablet is administered.
- In chronic megacolon, the main concern is to increase the mobility of the stomach and intestinal contents and promote defecation. Medications such as laxatives and enema drugs are given, along with a few alterations in the diet.
- In toxic megacolon; the first step is to try and minimize the infection for which broad-spectrum antibiotics are administered; if the infection does not subside in two to three days following the treatment, surgery (colectomy, a procedure to remove the colon as a whole or a part of the colon depending upon the need) is indicated. Also, antibiotics are prescribed post-surgery to promote proper healing and prevent further infections.
- Acute and toxic megacolon can mostly be cured as a whole if the patient responds well to the treatment. But, chronic megacolon is not completely curable.
Conclusion:
Megacolon is not a severe condition if proper treatment is sought at the right time. As most of the causes of megacolon are lifestyle-based and are easily correctable, managing a proper diet and following a proper lifestyle can prevent the acquired type of megacolon. Even if diagnosed with a megacolon, following the instructions suggested by the physician can help one fight it.
