Ulcerative colitis is an inflammatory bowel disease that affects the large intestine, especially the lower colon and rectum. Inflammatory bowel disease is a term that describes a group of diseases that affects the gastrointestinal tract. Inflammatory bowel disease involves Crohn’s disease and ulcerative colitis. Ulcerative colitis affects the inner lining of the colon, rectum, or both, which leads to inflammation, irritation, and ulceration. Ulcerative colitis may cause mild or severe symptoms, such as abdominal pain, diarrhea, bleeding per rectum, anemia, and weight loss. It may be dangerous and cause life-threatening complications that affect the skin, joint, bone, eye, liver, and lung. Also, ulcerative colitis may end in toxic megacolon or cancer colon. Ulcerative colitis is a chronic disease, and its symptoms develop gradually over a long period. Ulcerative colitis usually occurs in an intermittent course. Intermittent course means that there are asymptomatic periods between acute attacks of symptoms.
Ulcerative colitis affects both sexes in equal rate. It is common in those between 15 and 30 years old, but it also may occur in children or the elderly. Ulcerative colitis affects about 20 per 100000 people every year. In 2015, inflammatory bowel disease (ulcerative colitis and Crohn’s disease) affected about 11 million people and caused about 50000 death. It is more common in the United States, Canada, and Europe than in other areas of the world.
The exact cause of ulcerative colitis is unknown. It may be autoimmune, genetic, or environmental.
The diagnosis of ulcerative colitis depends on imaging by endoscopy and taking a biopsy from the affected tissue. Other tests and diagnostic tools may be useful to differentiate ulcerative colitis from other causes that may cause similar symptoms. Also, we need to screen for colon cancer as it is one of the most dangerous complications of ulcerative colitis.
Treatment of ulcerative colitis may be only with medications or surgery. Surgery may be essential in some conditions, such as severe complications or failure of medical treatment to control the symptoms. Also, some dietary changes may improve the symptoms.
» Now, we will discuss the ulcerative colitis in detail, and we will cover the following questions:
- What is the etiology of ulcerative colitis?
- What are the symptoms, signs, and complications of ulcerative colitis?
- What are the types of ulcerative colitis?
- How can your doctor diagnose ulcerative colitis?
- What are the components of the management plan of ulcerative colitis?
- What is the prognosis of ulcerative colitis?
– Finally, we will discuss ulcerative colitis in comparison to Crohn’s disease.
Etiology of ulcerative colitis
The exact cause of ulcerative colitis is unknown. The most accepted theory about its etiology is that ulcerative colitis is an autoimmune disorder. Also, genetic and environmental factors play a role.
- Autoimmune theory: Normally, the immune system protects the body against the harmful invaders, and it achieves that using the white blood cells. The healthy immune system can identify the invaders and destroy them without attacking the body tissue. In ulcerative colitis, the immune system treats the lining of the large intestine, normal beneficial bacteria, and food as foreign invaders and attacks them. When the immune system attacks the normal large intestine, this causes inflammation and ulceration.
- Genetic factors: Some researchers found abnormal genes in people with ulcerative colitis. These abnormal genes suggest a link between genetics and ulcerative colitis. Also, the increased risk in some ethnic groups, such as Ashkenazi Jewish, implies a role for genetics. Also, the risk of ulcerative colitis is higher in those with positive family history. Abnormal genes may alter the immune response and direct it to attack the body tissues in the large intestine.
- Environmental factors: Ulcerative colitis is more common in urban areas, such as western Europe and America. Some environmental factors may increase the risk of ulcerative colitis, such as air pollution, some diets, stress, and some medications. Medications, such as antibiotics, contraceptive pills, and non-steroidal anti-inflammatory drugs, may increase the risk of getting ulcerative colitis. Also, foods rich in unsaturated fats may increase the risk. The previous factors may raise the risk of developing ulcerative colitis or worsening of the symptoms.
Unlike Crohn’s disease, smoking doesn’t represent a risk factor in ulcerative colitis. The incidence of ulcerative colitis is lower among smokers; 80% of the patients are nonsmokers.
The clinical picture of ulcerative colitis
Ulcerative colitis mainly affects the colon and rectum. Also, ulcerative colitis doesn’t affect the gastrointestinal tract only. The autoimmune nature of the disease may lead to extraintestinal symptoms, such as skin, joints, eyes, blood cells, lungs, and liver.
A) Gastrointestinal symptoms:
The main presentation of ulcerative colitis is diarrhea, which is usually severe and with dysentery (mucus and blood in the stool). Other symptoms include:
- Tenesmus: It means the urgency to defecate with the inability to defecate despite this urgency.
- Abdominal pain in the left lower quadrant of the abdomen that varies in severity from discomfort to severe pain and cramping.
- Bleeding per rectum: The ulceration in the colon and the chronic nature of the disease leads to chronic bleeding that may result in anemia. Thus, patients with ulcerative colitis often feel fatigued due to this anemia.
- During flares up of the disease, fever, nausea, malnutrition, weight loss, and high frequency of abdominal movement may occur.
- In children, ulcerative colitis may lead to failure of growth and development.
The gastrointestinal symptoms depend on the severity of and the extent of inflammation along the colon and rectum.
B) Extraintestinal symptoms:
The autoimmune nature of the ulcerative colitis may cause manifestations outside the colon. These symptoms are less common than intestinal symptoms.
These symptoms include:
♦ Skeletal manifestations: In ulcerative colitis, the joint inflammation (arthritis) may affect the small peripheral joints in the hands and feet (peripheral arthritis), vertebrae (ankylosing spondylitis), or large joints. The inflamed joint is red, painful, warm, swollen, and with limited movement. Also, osteoporosis may occur, either secondary to the disease process or some medications used for treatment, such as corticosteroids.
♦ Skin manifestations: The skin of these patients may show:
- Erythema nodosum (painful and red subcutaneous nodules) on the front of the legs
- Pyoderma gangrenosa (ulcerated skin lesions)
- Aphthous stomatitis (shallow and tender ulcers in the mouth)
♦ Eye manifestations: Uveitis and iritis may occur, leading to a blurring of vision, eye pain, and photophobia. Without proper treatment, uveitis may end in permanent blindness. Also, scleritis and episcleritis may occur.
♦ Autoimmune hemolytic anemia due to the autoimmune destruction of red blood cells
♦ The risk of clot formation increases in patients with ulcerative colitis, especially in the legs and lungs. The painful red swelling in the legs may indicate a deep venous thrombosis. Dyspnea (difficult breathing), chest pain, and cough may indicate pulmonary embolism.
♦ Liver manifestations: Primary sclerosing cholangitis affects 5% of people with ulcerative colitis. It means inflammation of the small and large bile ducts that leads to fibrous thickening and multiple strictures in the ducts. Also, fatty liver (fat deposition in the liver) may occur and cause pain and discomfort in the right hypochondrium.
♦ Interstitial pulmonary fibrosis may occur and cause breathing problems, such as dyspnea.
Most people with ulcerative colitis show mild to moderate manifestations. Only about 10% may show severe symptoms, such as fever and severe abdominal pain.
Complications of ulcerative colitis
Ulcerative colitis may lead to complications, such as anemia, dehydration, and disability (due to extraintestinal involvement). It also may cause growth retardation in children. But, the most dangerous complications are cancer colon and toxic megacolon.
1. Cancer colon: Patients with ulcerative colitis shows a significant risk of cancer colon 10-20 years after disease onset. Thus, these patients should undergo regular screening for colon cancer.
2. Toxic megacolon: It is a condition in which the colon becomes atonic and distended due to the accumulation of gases. It is a life-threatening condition because the colon may rupture, and the bacteria enter the blood, causing septicemia. It causes fever, tachycardia (rapid heart rate), dehydration, and abdominal pain. It may require surgical resection of the colon to save the patient’s life.
Types of ulcerative colitis
Types of ulcerative colitis depends on the site of the inflammation. Doctors classified ulcerative colitis into the following types:
- Ulcerative proctitis: This type only affects the rectum, and the rectal bleeding may be the only sign of this type. It is the mildest form of ulcerative colitis.
- Proctosigmoiditis: This type affects the rectum and sigmoid colon (the lower end of the colon). The manifestations of this type include abdominal pain, bloody diarrhea, and tenesmus (urgency to defecate with the inability to defecate despite this urgency).
- Left-sided colitis: This type affects the rectum, sigmoid colon, and left part of the colon (descending colon). This type shows left-sided abdominal pain, bloody diarrhea, and weight loss.
- Acute severe ulcerative colitis: It is a rare type of ulcerative colitis, and it causes fever, severe abdominal pain, bleeding, profuse diarrhea, and nausea.
- Pancolitis: This type affects the whole colon. It causes severe bloody diarrhea, abdominal pain and cramps, fatigue, and significant weight loss.
Also, we can classify ulcerative colitis according to its severity into the mild, moderate, severe, and fulminant, as follows:
- Mild ulcerative colitis means defecation at a rate lower than four times daily. Also, it may show mild abdominal pain and rectal bleeding. Signs of toxicity, such as fever and weight loss, don’t occur in this type. Also, inflammatory markers (ESR and CRP) are within a healthy range.
- Moderate ulcerative colitis means defecation at a rate higher than four times daily. The signs of toxicity are minimal in this type. This type shows low-grade fever (37.2:38.5 degrees), moderate abdominal pain, and anemia that doesn’t need a blood transfusion.
- Severe ulcerative colitis means defecation at a rate higher than six times daily. This type also shows bloody stools and toxicity signs, such as fever, anemia, tachycardia, and high levels of inflammatory markers.
- Fulminant ulcerative colitis is a life-threatening condition. It shows defecation at a rate higher than ten times daily, abdominal pain and tenderness, abdominal distension, and toxicity signs. It also exhibits continuous bleeding that requires a blood transfusion to compensate for the blood loss. It may cause toxic megacolon and bowel perforation, which are fatal conditions.
Diagnosis of ulcerative colitis
Frist, the doctor will hear your complaint and ask you about your symptoms, such as bloody diarrhea, rectal bleeding, and abdominal pain. He will ask you about general health and your medical history. He also will ask you about your family history.
After history taking, your doctor will perform a physical examination to see findings, such as abdominal pain and tenderness, abdominal distension and swelling, paleness of anemia, and other extraintestinal manifestations. He also will listen to the intestinal sounds by stethoscope.
After history taking and physical examination, your doctor will suspect more than a disease can cause these symptoms. Thus, he will request further investigations to rule out other conditions, confirm his diagnosis, and determine the extent and severity of the disease.
These investigations include:
- Blood examination: Complete blood count (CBC) may show low red blood cell count, which indicates anemia. Also, blood examination may show inflammatory markers and specific antibodies, such as pANCA (perinuclear antineutrophil cytoplasmic antibodies), that appear in 70% of the cases.
- Stool examination: Stool samples may reveal white blood cells and lactoferrin, which indicates intestinal inflammation. It also rules out infections, such as bacterial, viral, or parasitic infections. The fecal calprotectin test is sensitive to ulcerative colitis. This test becomes elevated early in the disease even before inflammatory markers, which helps in the prevention of disease progression.
Blood and stool examination are helpful, but confirmation of ulcerative colitis requires visualization of the large intestine to see the lesion. The most accurate techniques that enable the doctor to visualize the large intestine are endoscopies that include:
The Flexible sigmoidoscopy is a thin, flexible tube that contains a camera to visualize the rectum and sigmoid colon. The doctor will insert this endoscope through the anus, and the camera will send a video image for the lining of the rectum and sigmoid colon. The doctor may need to take a biopsy by the endoscope to send it to a pathologist for examination. If the diagnosis is unclear or the doctor thinks that ulcerative colitis affects more than the rectum and sigmoid colon, he may do a full colonoscopy.
The Colonoscopy is a thin, flexible tube attached to a camera like the flexible sigmoidoscopy, but it allows the doctor to examine the entire colon during the procedure. Like flexible sigmoidoscopy, the doctor can take biopsies from the colon to send it for pathological examination.
In ulcerative colitis, the previous endoscopic techniques will show:
-
- Erythema (redness) and friability of the colonic mucosa
- Ulcers in the colon
- Loss of the natural appearance of the colon
- Abnormal growths called polyps (in 15% of the cases)
- The lesion in ulcerative colitis always involves the rectum and extends to the colon in a continuous pattern.
Endoscopy determines the type of disease according to the extent of the lesion.
If the diagnosis is still unclear, the doctor will request a biopsy from the affected area of the bowel at the time of endoscopy. Histological examination of a biopsy can make a definitive diagnosis and exclude Crohn’s disease.
In ulcerative colitis, the biopsy will show the following:
-
- The lesion is limited to the mucosal and submucosal layers of the bowel wall. Unlike ulcerative colitis, Crohn’s disease affects the entire bowel wall (mucosa, submucosa, and muscle layer)
- Crypt abscesses
- Hemorrhage and inflammatory cells
Also, biopsies are useful in screening for cancer colon, which is the most dangerous complication of ulcerative colitis.
Other imaging techniques, such as X-ray and CT scan, are less useful in the diagnosis of ulcerative colitis. But, the doctor may need them to see if there are dangerous complications, such as toxic megacolon or perforated colon.
After the diagnosis of ulcerative colitis, the doctor can put his management plan, according to what he found. The management plan will depend on the severity and the extent of the disease, how often the condition flares up, and the presence of complications.
» Now, let’s discuss the treatment options of ulcerative colitis.
Treatment of ulcerative colitis
The treatment of ulcerative colitis aims to induction a remission and maintenance of remission. Induction of remission treatment aims to relieve the symptoms and give a chance for the colon to heal from the ulcers. Maintenance remission means the prevention of further relapse.
Treatment of ulcerative colitis includes medications, surgery, and diet modifications. The treatment differs among the cases; thus, your doctor may time to adjust the treatment plan to achieve the goals of treatment. The duration of treatment will depend on the severity of the disease and the response to treatment, but most cases require a long course of treatment that may take many years.
A) Medications for ulcerative colitis include:
Amino salicylates (for example, Sulfasalazine)
It is the first choice in the treatment of ulcerative colitis, especially in mild and moderate cases. It reduces and maintains remission by reduction of the inflammation. Its initial dose is 1 gm per 6 hours to induce a remission, then a maintenance dose 2 gm daily after the remission and for two years. The route of administration depends on the site of the disease; it is available in oral, enema, and suppository forms.
Corticosteroids (for example, Prednisone)
They are potent anti-inflammatory medications, but due to their many side effects, the doctors use them only for short periods as possible. The main indication of corticosteroids is during an active flare-up of the disease if the Amino salicylates can’t control the condition alone. As Aminosalicylates, corticosteroids are available in oral, enema, and suppository forms.
Immunosuppressive drugs (for example, Azathioprine and Cyclosporine)
These drugs act by reducing the inflammation by inhibition of the immune system to make it unable to attack the colon. These drugs may lead to a lot of dangerous side effects, such as recurrent infections and bone marrow depression, which limits their use to the cases that didn’t achieve remission by Amino salicylates or corticosteroids.
Biologic agents (for example, Infliximab and Vedolizumab)
These medications act by inhibiting tumor necrosis factor protein, which is one of the immune system proteins. These medications are powerful, and their response rate is high. But, these medications may lead to dangerous side effects, such as the increased risk of cancers and dangerous infections, heart failure, incoordination, and allergic reaction. Patients who take these medications should undergo a continuous evaluation to assess the effectiveness of the drug and to prevent any dangerous side effects. Doctors may apply these drugs either early in the treatment or after the failure of the previous medications to induce a remission.
Other symptomatic treatments may be useful in ulcerative colitis, such as:
-
- Antibiotics: to prevent infections that may interfere with the healing of the colon
- Antidiarrheal medications: Don’t take these medications without consulting your doctor
- Bacterial recolonization (probiotics): They are beneficial living bacteria that improve the status of the colon by restoring the normal intestinal flora. Probiotics help in the induction and maintenance of remission.
- Iron therapy and blood transfusion: to treat the anemia
Hospitalization of patients with ulcerative colitis
Hospitalization may be necessary for severe cases to correct the dehydration and any electrolyte disturbance that results from severe diarrhea. Also, other complications may require hospitalization as severe bleeding, toxic megacolon, and colon perforation.
B) Surgery in ulcerative colitis:
Surgery is curative in ulcerative colitis, but the extraintestinal symptoms may persist after surgery. About 25% of patients with ulcerative colitis need surgical intervention. The doctors keep this surgical intervention to specific circumstances.
Indications of surgery include:
- Failure of medical treatment to control the symptoms and frequent flares-up that impair the quality of life
- Severe bleeding that may lead to death
- Toxic megacolon and colon perforation require immediate surgery
- Strong suspicion of colon carcinoma
- Any severe complications or symptoms that threats the patient’s life or disable him
Although surgery is curative, doctors don’t prefer them in early and mild cases that can be controlled by medical treatment because surgical procedures may lead to impacts on the patient life and may carry risks.
The standard surgical procedure in ulcerative colitis is proctocolectomy. It means the total removal of the large intestine (rectum and colon). The surgeon can perform proctocolectomy by two procedures:
-
- Proctocolectomy with ileal pouch-anal anastomosis
- Proctocolectomy with end ileostomy.
Let’s discuss each of them in some detail.
1) Proctocolectomy with ileal pouch-anal anastomosis (J-pouch surgery):
It is the most performed surgery in ulcerative colitis. In this procedure, the surgeon removes the colon and rectum, then creates a pouch (J-pouch) by the small intestine. Then, the surgeon connects this pouch to the anus, which allows the stool to pass through its normal pathway from the anus.
The surgeon may perform this procedure in one, two, or three stages, as follow:
-
- The first stage involves subtotal colectomy, which means the removal of the colon only without the rectum. In this stage, the surgeon creates a temporary ileostomy.
- The second stage involves proctectomy (removal of the rectum) and the creation of the pouch. But, the surgeon will create a new ileostomy to allow the pouch to heal with the small intestine and anus. During this period, the intestinal wastes will pass into a removable ostomy bag.
The surgeon will determine the way of the procedure based on your general health and the severity of the disease. This procedure doesn’t restore the normal bowel function immediately. You may have up to 15 bowel movements daily, and your stools may be liquid or soft in the following months after the procedure. The bowel status will improve gradually, as the pouch increase in size, and the anal muscles strengthen. Most patients have six bowel movements daily after one year.
This surgery cures ulcerative colitis, but some complications may occur, such as pouchitis. Pouchitis means inflammation of the pouch, which leads to symptoms, such as diarrhea, abdominal cramps, fever, and joint pain. Pouchitis need antibiotic treatment. Pouchitis is the most common complication, but there are other rare complications, such as fistulas and pouch failure. According to the severity of the condition, your doctor may need revision surgery to decide the need to repeat the surgery.
2) Proctocolectomy with end ileostomy:
In this procedure, the surgeon will remove the entire large intestine (colon, rectum, and anus). After that, he will create a new pathway for the stools. The surgeon will create a stoma (small hole in the abdominal wall) and connect the terminal ileum (the terminal part of the small intestine) to this stoma. Thus, the intestinal contents will pass through this stoma to the external ostomy pouch (or bag) that you should evacuate several times daily.
Some complications may occur, such as infection, prolapse (bulging), or retraction of the stoma. These complications require immediate seeing of your doctor.
You may need an adaptation period for about one year to adapt to the changes in your body. Follow your doctor’s instructions about diet and physical activity after surgery. In the first days after surgery, you should be on liquids and soft foods. Gradually, you will return to solid foods, but you should avoid foods that cause irritation and diarrhea. Also, it is useful to drink a lot of water. Also, your doctor may recommend the limitation of physical activity for a period.
After surgery, you can return to your active life with an ileostomy. See your doctor or a mental health professional if you felt depression or anxiety because your mental health is important as your physical health.
Cancer surgery and screening:
Patients with ulcerative colitis have a high risk of colorectal cancer. Thus, they should undergo screening by colonoscopies every one or two years. The doctor takes biopsies with the colonoscope to send it for pathological examination. If the doctor found any precancerous tissue, such as dysplasia or polyps, he should recommend the surgical removal of the colon and the rectum. This surgery eliminates the risk of colorectal cancer.
C) Lifestyle and diet:
There is no specific diet plan that can affect ulcerative colitis. The research didn’t find certain foods causing ulcerative colitis. But, some foods may worsen your symptoms or increase the incidence of flare-ups. Some dietary changes may help in the control of the symptoms during a flare-up and may prolong the remission between the flares.
Some beneficial dietary changes:
- Eat small frequent meals instead of two or three large meals.
- Drink a lot of water: In ulcerative colitis, dehydration may occur due to fluid loss on diarrhea; thus, drinking plenty of water is useful to compensate for this fluid loss and avoid dehydration.
- Avoid alcohol, caffeine, fizzy drinks, and spicy food because these drinks and foods may worsen your symptoms, especially diarrhea.
- Limit the high-fiber foods, especially during the flare-ups. If you want fruits and vegetables, you should bake them and don’t eat them fresh.
- Talk with your doctor about if you need food supplements, such as vitamin-C. You may not take adequate vitamins and minerals in your diet; thus, you may need supplementary foods.
- Avoid dairy diet because it may worsen diarrhea and abdominal pain. Your body may be unable to digest lactose (lactose intolerance); thus, it is useful to limit the dairy diet and consume a lactose-free diet.
- Avoid high-fat diet. Some studies suggested that the low-fat diet decreases the frequency of flares. Also, it is useful to take a healthy fat, such as omega-3 fatty acids and olive oil.
- Eat a high-caloric and low-salt diet.
- Consult a dietitian about your dieter changes and talk to him if you felt weight loss.
A food diary is a useful and smart way to track your diet and see what affects you and how you feel after certain foods. Record the foods and identify what may cause diarrhea or abdominal discomfort to eliminate them. Discuss the foods that you eliminated with your doctor to compensate for any nutrient loss.
Stress doesn’t cause ulcerative colitis, but it may worsen the symptoms and increase the incidence of flares. Stress management helps to improve the condition and reduces the incidence of flares.
Stress management techniques include methods, such as:
-
- Exercise relieves stress and improves mood. Discuss a suitable exercise program with your doctor.
- Relaxation and breathing exercises, yoga, and meditation
- Don’t give in to isolation, depression, or anxiety due to your condition. Discuss your mental status with your doctor and communicate with your society.
Prognosis of ulcerative colitis
Ulcerative colitis is an intermittent disease with periods of remission and exacerbation. Proctitis and left-sided colitis are mild types with a benign course. The diseases progress proximally only in 15% of people with these types, and 20% of them have remission for long periods independent of treatment. People with more extensive types have shorter periods of remission. Some patients have rapidly progressive disease, and these people usually don’t respond to the treatment, and they will need surgery within a few years of the disease onset.
The need for surgery varies according to the patient’s condition, but some risk factors raise this need, such as:
- An extensive disease that involves most of the large intestine
- Severe inflammation and persistent elevated inflammatory markers
- Previous history of hospitalization due to ulcerative colitis
- Young age patients
Ulcerative colitis doesn’t usually affect the fertility of patients, especially female patients. But, infertility may occur as a complication of surgery, especially pouch surgery. The risk of infertility is lower in the end ileostomy surgical procedure.
Female patients, who decide to be pregnant, will mostly get a healthy child without problems in pregnancy. But, pregnant females with ulcerative colitis should review the management plan with the health care team. Doctors may change some medication to avoid any adverse effects. Also, the doctor will recommend the control of ulcerative colitis before pregnancy to prevent flares during the pregnancy.
Ulcerative colitis in children manifests as in adults. But, it may impact the child growth and development. Some medications may be unsuitable for children, such as enemas and immunosuppressants. Thus, surgery may be essential to control the disease in children.
The risk of colorectal cancer increases -after ten years of disease onset-, especially when the disease involves more than the descending (left-sided) colon. People with only proctitis don’t have a high risk of cancer. Screening colonoscopies and biopsies are essential to identify any precancerous lesion and remove it.
The risk of mortality in ulcerative colitis isn’t higher than the general population. But, the causes of death in these patients differ from the general population. Infection with some organisms, such as clostridium difficile and cytomegalovirus (CMV), may predict a higher risk of mortality.
Ulcerative colitis vs. Crohn’s disease
Let’s discuss how they differ:
1) The affected site
Crohn’s disease affects any part of the gastrointestinal tract, especially the ileocecal regions, and it usually doesn’t affect the rectum. The lesion extends in a discontinuous pattern (Skip lesions) and affects all three layers of the intestinal wall (transmural lesion).
Ulcerative colitis always affects the rectum and extends proximally to involve the colon. It affects the terminal part of the ileum only in 5% of the cases. The lesion extends in a continuous pattern and affects only the first two layers of the intestinal wall (mucosa and submucosa).
2) Pathology
Crohn’s disease shows granuloma on biopsy and severe stricture on endoscopy.
Ulcerative colitis shows crypts abscesses on biopsy, but there is no stricture or granulomas.
Also, biopsies show a transmural lesion in Crohn’s disease. But, they show only mucosal and submucosal affection in ulcerative colitis.
3) Age and gender
Crohn’s disease affects males and females equally and doesn’t have a specific age.
Ulcerative colitis slightly more in females, and it is more common in those between 15 and 30 years old.
4) Smoking
The incidence of Crohn’s disease is higher among smokers; thus, smoking increases the risk of Crohn’s disease.
The incidence of ulcerative colitis is lower among smokers. 80% of patients with ulcerative colitis are nonsmokers.
5) Clinical picture
› Diarrhea
Diarrhea occurs in both diseases, but in ulcerative colitis, it is severe and usually with dysentery (mucus and blood in the stool). In Crohn’s disease, diarrhea is porridge-like and may occur with steatorrhea (excess fat in the stool).
› Tenesmus
It is more common in ulcerative colitis than Crohn’s disease.
› Abdominal pain
In Crohn’s disease, there is more prominent pain in the right lower quadrant of the abdomen.
In Ulcerative colitis, there is less prominent pain in the left lower quadrant of the abdomen.
› Bleeding per rectum
It occurs with ulcerative colitis, but it is uncommon with Crohn’s disease.
› Fever
Fever is common with Crohn’s disease, but it indicates a severe condition in ulcerative colitis.
› Weight loss
It often accompanies Crohn’s disease, but it is rare with ulcerative colitis.
› Anal and oral lesions occur with Crohn’s disease, but they are rare with ulcerative colitis.
› Intestinal fistula commonly occurs with Crohn’s disease, but it is rare with ulcerative colitis.
› Intestinal obstruction may happen only with Crohn’s disease; it doesn’t occur with ulcerative colitis.
› Malabsorption syndrome may happen with Crohn’s disease; it doesn’t occur with ulcerative colitis.
› Nutrient deficiency
In ulcerative colitis, there is no nutrient deficiency. But, in Crohn’s disease, there is a high risk of vitamin B12 deficiency, which causes megaloblastic anemia, neurological manifestations, and gastrointestinal manifestations.
Crohn’s disease causes vitamin B12 deficiency because it affects the terminal ileum, which is the site of vitamin B12 absorption.
› Primary sclerosing cholangitis is frequent in ulcerative colitis and infrequent in Crohn’s disease.
6) Complications
› The risk of cancer
The risk of cancer is low in Crohn’s disease while it is high in ulcerative colitis, especially after ten years of the disease onset.
› Toxic megacolon
It is rare in Crohn’s disease because it usually doesn’t involve the colon and rectum. But, in ulcerative colitis, the risk is high. Toxic megacolon is a life-threatening complication of ulcerative colitis.
7) Diagnosis
› Endoscopy and biopsy will show:
– In Crohn’s disease: There is an affection of the entire intestinal wall of any part of the gastrointestinal tract, especially the terminal ileum, in a discontinuous pattern, and granuloma formation
– In ulcerative colitis: There is an affection of the rectum with or without the colon in a continuous pattern. Only the mucosa and submucosa are affected. Crypt abscesses appear in 30% of the cases.
› Laboratory tests
– In ulcerative colitis, blood examination shows an autoantibody called pANCA (perinuclear antineutrophil cytoplasmic antibodies). Also, the fecal calprotectin test is sensitive to ulcerative colitis.
– In Crohn’s disease, blood examination shows an autoantibody called ASCA (Anti-saccharomyces cerevisiae antibody).
8) Management
› Sulfasalazine is more useful in ulcerative colitis than in Crohn’s disease.
› Antibiotics are more effective in the long term in Crohn’s disease.
› Surgery usually cures ulcerative colitis, but Crohn’s disease often returns after removal of the affected part.