Crohn Disease

What is Crohn Disease?

Crohn’s disease is a type of inflammatory bowel disease, similar to ulcerative colitis but usually shows less obvious symptoms. It involves inflammation of the entire thickness of the digestive tract wall, triggered by the immune system.

The inflammation can occur anywhere along the digestive tract. Research from Minnesota reveals that within three months of diagnosis, 19% of patients develop complications such as strictures (narrowing of the tract) or fistulas (abnormal connections between different parts of the tract). Almost half of all patients develop some sort of intestinal complication, like fistulas, inflammations, strictures, or abscesses, within 20 years from when they were diagnosed. Studies from Northern Europe and Minnesota show that a third of cases involve the last part of the small intestine, the junction of the small and large intestine, or the colon respectively. Only around 6% to 14% of patients show a shift in disease location. Patients having the disease in the upper digestive tract or at the junction of small and large intestine face a bigger risk of strictures and fistulas than those with the disease in the colon. Crohn’s disease can also affect other areas of the body, commonly the eyes, skin, liver, and joints.

The disease continuously persists and often gets worse over time. Typical symptoms include diarrhea, stomach pain, nausea, or vomiting. Weight loss, fever, and tiredness are the body’s general responses to this disease. If left untreated, the long-term inflammation can lead to serious complications. Early detection and management of Crohn’s disease can significantly improve the patient’s quality of life and health outcomes.

What Causes Crohn Disease?

The exact cause of Inflammatory Bowel Disease (IBD), which includes conditions like Crohn’s disease, is still unclear. However, research suggests it might be due to an overly strong immune response to things in the environment. These can include things like medications, toxins, infections, or bacteria in the gut. This reaction generally happens in individuals who are genetically prone to it. Wide-ranging studies of our genetic material have pinpointed over 200 genes linked to IBD, and 71 locations on genes that increase the risk of Crohn’s disease.

Certain genetic differences are connected to specific variations of Crohn’s disease. For instance, changes in genes called NOD2/CARD15 have been found in people with Crohn’s disease that affects the last part of the small intestine and is more severe. These people are usually younger and often need surgery. In the future, studying a person’s genes may provide clues about how severe their disease might be. However, for now, this genetic testing is mostly used for research purposes.

Risk Factors and Frequency for Crohn Disease

Crohn’s disease, more often found in North America, Northern Europe, and New Zealand, usually develops in people during two age periods: between 15 to 30 and 40 to 60. It’s noticed more frequently in city dwellers than people living in rural areas. Furthermore, it’s common in people of Northern European ancestry and Jews, with about 3.2 in every 1000 individuals affected. On the other hand, its occurrence in Asian, African, and South American populations is comparatively few. However, recent research has observed an increasing number of cases in rapidly industrializing regions of Asia, Africa, and Australasia.

• Crohn’s disease is most commonly seen in North America, Northern Europe, and New Zealand.
• It often starts in two age groups: between 15 to 30 and 40 to 60.
• People living in cities are more likely to have it than those in rural areas.
• Northern Europeans and Jewish people have a high rate, reaching about 3.2 in every 1000 individuals.
• Conversely, it’s less common among Asian, African, and South American populations.
• Nonetheless, there’s a significant rise in incidence in areas of Asia, Africa, and Australasia that are rapidly industrializing.

Signs and Symptoms of Crohn Disease

Crohn’s disease is a condition where parts of the digestive system become inflamed. How this disease shows up can greatly differ, dependent on the person and the parts of the digestive system affected. Some people may experience frequent episodes of mild belly pain, diarrhea, passing gas, and fever. These uncomfortable episodes often happen during times of mental or physical stress and are followed by periods of no symptoms, which can last weeks to months.

For some individuals with Crohn’s disease, their symptoms might seem close to acute appendicitis. These might include fever, diarrhea, and pain in the lower right side of the abdomen. If Crohn’s disease affects the little intestine (ileum) and the large intestine (colon), one may feel recurring pain in the lower right side of the abdomen and frequent diarrhea. Higher temperatures are mostly a sign of a different health condition, such as an abscess. Rapid weight loss may happen over time due to the diarrhea and fear of eating food as it worsens the pain.

• Recurrences of mild belly pain
• Diarrhea
• Pain in the lower right abdomen
• Fever
• Rapid weight loss

Crohn’s disease, across time, can lead to complications like thinning of the intestinal walls and creating abnormal connections between organs. These connections, known as fistulas, may cause bothersome symptoms. For example, recurrent urinary tract infections might be caused by a fistula connecting the intestine and the bladder.

Moreover, if the disease affects the part of the small intestines, called the jejunum, it can cause poor absorption of nutrients from food resulting in nutritional deficiencies. Therefore, nutrients like iron, protein, calcium, magnesium, and vitamins may not be properly absorbed leading to various symptoms depending on the deficiency.

Crohn’s disease relating to the colon presents with symptoms like blood in the stool, painful bowel movements, and complications like fistulas and abscesses around the anus. In severe cases, surgery might be required due to obstruction in the colon. In women, this form can lead to an abnormal connection between the rectum and the vagina, known as a rectovaginal fistula.

Furthermore, people suffering from Crohn’s disease might experience symptoms related to the upper digestive tract, such as vomiting, nausea, and stomach pain.

• Bleeding in the stool
• Pain during bowel movements
• Vomiting
• Nausea
• Stomach pain

Implications of Crohn’s disease aren’t limited to the digestive system. Various parts of the body can show signs of the disease:

• Eyes: inflammation of different parts of the eye
• Mouth: inflammatory mouth sores
• Liver: conditions like gallstones or infection of the bile duct
• Kidneys: formation of kidney stones or urinary tract infections
• Joints: inflammation of joints
• Skin: inflammatory skin conditions

People with Crohn’s disease also have an increased risk of getting blood clots. Hospitalized patients with limited ability to move are particularly susceptible to serious complications such as deep vein thrombosis, stroke, or blockage in the lungs.

Physical examination is crucial for diagnosing and managing Crohn’s disease. Symptoms such as pale complexion and low weight might suggest poor nutrition. In advanced stages of Crohn’s disease, the skin over the affected area of the abdomen might show signs of a fistula, a complication of the disease. Tenderness on touch or guarding (voluntary contraction of the abdominal wall) are also important signs that help clinicians assess the area affected by the disease and its severity. Examination of the skin, eyes, mouth, and joints can help detect any symptoms of Crohn’s disease outside of the digestive system. Additionally, other organs, like the liver and kidneys, might be affected.

Examinations to determine neurological deficits due to vitamin deficiencies, such as reduced sensation or muscle wasting, also form an integral part of the overall physical assessment. Therefore, it’s important for doctors to conduct a detailed physical examination not only to diagnose Crohn’s disease, but also to assess its severity, detect any complications, and determine the best course of treatment.

Testing for Crohn Disease

In order to rule out certain infections, your doctor might request stool tests. These can help identify active Crohn’s disease and are used to monitor its activity.

Your doctor might also order a blood test, which can reveal issues like anemia or liver disease, caused by deficiencies in vitamins like B12 and iron. A blood test can also indicate if your kidneys and liver are functioning properly and if there are imbalances in your electrolytes, which might happen due to diarrhea. A urinalysis can show if there are bacteria and white blood cells. Tests measuring specific nutrients, such as iron and calcium, can help your doctor identify any deficiencies.

There are also special blood tests, for instance, c-reactive protein (CRP) tests and erythrocyte sedimentary rate tests, which can give information about the severity of inflammation in your body.

An X-ray might be requested if there is a suspicion of bowel obstruction. Small bowel follow-through, a type of X-ray, is often used to check if the lower part of the small intestine is involved. It can also identify abnormal connections (fistulas) between body parts.

Your doctor might also request to perform an abdominal ultrasound during flare-ups of the disease or to monitor how you are responding to treatment. Ultrasound does not involve radiation and is widely available; however, it may not provide very detailed images. It can help identify some features such as fistulas, fluid in the abdomen, abscesses, and increased blood flow in the superior mesenteric artery.

An MRI or a CT scan of the abdomen and pelvis can provide clearer images and can identify abscesses, strictures, and fistulas. MRI is often preferred over CT scan, especially in children, because it exposes them to less radiation.

Your doctor might also suggest an upper endoscopy or a colonoscopy, which allows the inside of your intestine to be visualized and biopsied. These tests can assess the extent of inflammation in the bowels and confirm a diagnosis of Crohn’s disease.

Video capsule endoscopy can visualize the small intestines, which might not be reachable with a conventional endoscopy or colonoscopy. However, it should be used carefully in patients with known strictures, as it could potentially get stuck.

Before starting treatment for Crohn’s disease, your doctor would need to know your vaccination history, as these treatments suppress the immune system. They would also test for tuberculosis, particularly if you’re starting anti-TNF biologics. Another important test before starting treatment is for thiopurine methyltransferase (TPMT) levels. Low TPMT levels can increase the risk of side effects, and high levels may affect the effectiveness of treatment.

Treatment Options for Crohn Disease

Crohn’s disease is typically managed with medication, surgery, and diet. The process generally involves controlling inflammation within the first three months, followed by a maintenance phase that aims to extend the symptom-free period. The choice of medication will depend on the individual’s risks and the severity of their condition.

Here are some of the commonly used medications:

• Mesalamine and sulfasalazine are anti-inflammatory drugs used to treat mild to moderate disease. They may not be as effective for Crohn’s disease as they are for ulcerative colitis, and they are not effective for disease in the small intestine.
• Corticosteroids are used to control flare-ups and stabilize the condition until other treatments can take effect. They should not be used long-term because of side effects like osteoporosis, osteonecrosis, and adrenal insufficiency.
• Immunomodulators help manage moderate Crohn’s disease and are used as steroid-sparing drugs in maintenance therapy. They are not used to induce remission immediately as they tend to act slowly. The dosages and specific drugs used varies, and these drugs may be initially combined with steroids.
• Anti-TNF agents are used for moderate to severe disease and can come into effect within two weeks of initiation.
• Leukocyte trafficking agents inhibit certain proteins on T cells, preventing them from binding to cells in the gut lining and causing inflammation.
• IL-12/23 agents are used in patients who haven’t responded to corticosteroids, immunomodulators, or anti-TNF treatment.
• JAK inhibitors affect the function of certain kinases that contribute to the immune response. They come into effect relatively quickly, within about two weeks of initiation.

In some cases, surgery may be necessary to treat complications such as bowel obstruction, fistulas, abscesses, perforated bowel, dysplasia, cancer, or condition that doesn’t respond to medication. Depending on the circumstance, surgical resection or stricturoplasty may be considered. In some cases, a total colectomy may be needed for patients with severe disease.

Monitoring of disease activity is essential, and this usually involves tracking symptoms and levels of certain biomarkers. This can be done routinely every 6 to 12 months for patients in remission and more frequently for those needing dosage adjustment.

Following a special diet can also be an important part of managing Crohn’s disease. Since individuals with this disease are at risk of malnutrition and deficiencies in certain nutrients, advice from a dietitian and nutritional supplementation may be beneficial. Some dietary therapies, such as elemental and semielemental diets, can effectively reduce inflammation. However, their benefits may not be long-lasting due to the return of inflammation once the patient resumes a normal diet.

What else can Crohn Disease be?

When a doctor is evaluating a patient for possible Crohn’s disease, there are several other conditions they must consider before making their final diagnosis. This process is critical to ensure that any similar conditions are not mistaken for Crohn’s disease.

These other conditions fall into three categories:

• Infections that affect the small intestine and the end of the small intestine:
  • Coccidioides (a type of fungus)
  • Histoplasma (another type of fungus)
  • Salmonella (a type of bacteria that cause food poisoning)
  • Tuberculosis (a serious infectious disease that mainly affects the lungs)
  • Yersinia (a bacteria that can cause various illnesses depending on the strain)
• Infections that affect the large intestine:
  • Amebiasis (a parasitic infection of the intestines)
  • Campylobacter (a type of bacteria causing food poisoning)
  • C.difficile (a bacteria that can cause infections affecting the colon)
  • Cytomegalovirus (a herpes virus that can cause a variety of diseases)
  • E.coli (a bacteria that can cause diarrhea and other illnesses)
  • Salmonella (a type of bacteria that causes food poisoning)
  • Shigella (a bacteria causing dysentery)
• Noninfectious conditions:
  • Behcet’s disease (a rare disorder causing blood vessel inflammation)
  • Common variable immunodeficiency (an immune disorder)
  • Diverticulitis (inflammation of pouches in the colon)
  • Drug-induced colitis (inflammation of the colon caused by medication, such as nonsteroidal anti-inflammatory drugs and immunotherapy)
  • Ischemic colitis (inflammation of the colon caused by reduced blood flow)
  • Sarcoidosis (an inflammatory disease that could affect any organ)
  • Segmental colitis associated with diverticulosis
  • Small vessel vasculitis (an inflammatory condition affecting small blood vessels)
  • Solitary rectal ulcer syndrome

In order to accurately diagnose Crohn’s disease, it’s important to review the patient’s history of travel and possible exposures to infections. A series of appropriate laboratory, imaging, and tissue tests can also aid in differentiating these various conditions from Crohn’s disease.

What to expect with Crohn Disease

High-risk patients with severe Crohn’s disease usually present certain symptoms and conditions. They are typically under 30 years old and have a history of tobacco use. Elevated levels of CRP or fecal calprotectin and deep ulcers observed during a colonoscopy are also common. Risk factors also include problems affecting a long section of the bowel, issues around the anus, and symptoms impacting areas outside of the intestines. Having had previous bowel removal surgeries is another contributor.

Without certain therapies, up to half of these patients may build up a dependency on steroids or become resistant to treatment. After diagnosis, the need for abdominal surgery over the next decade increases to 46.6%. After surgery, there’s a 90% risk of the disease recurring at or above the surgical joint. Factors that increase early recurrence risk include cigarette smoking, a short time between diagnosis and first surgery, a need for multiple surgical procedures, and penetrating disease. Therefore, doctors recommend checking the status of the surgical area within 6 to 12 months after surgery and repeat the procedure every 1 to 3 years if there is no recurrence.

Previous studies suggest a slight increase in mortality rate in patients with Crohn’s disease compared to the general population, with a standard mortality rate ranging from 1.4 to 1.5. Death is usually linked to gastrointestinal disease, gastrointestinal cancer, and lung disease. Current use of corticosteroids is also associated with increased mortality.

Possible Complications When Diagnosed with Crohn Disease

Crohn’s disease is a condition that affects the body as a whole, and has numerous effects both inside and outside of the intestines. Below are some potential complications that can arise from this condition. It’s important to detect the disease early and follow the treatment plan closely to lessen the likelihood of these complications.

• Narrowing of the intestines (Stricture formation)
• Abnormal connections and pus-filled pockets in the intestines (Fistulae and abscesses)
• Cancer in the colon and rectum (Colorectal carcinoma)
• Spinal inflammation (Ankylosing spondylitis)
• Inflammation in the white part of the eye and the iris (Episcleritis, iritis)
• Skin disorders causing tender lumps and painful sores (Erythema nodosum, pyoderma gangrenosum)
• Kidney stones (Nephrolithiasis)
• Gallstones (Cholelithiasis)
• Anemia or low red blood cells
• A high risk of blood clots (Hypercoagulable state)
• Weak and brittle bones (Osteoporosis)
• Death of bone tissue (Osteonecrosis)
• Lack of vital nutrients (Macro and micronutrient deficiencies)
• Infections

Preventing Crohn Disease

Preventing Crohn’s disease is a difficult task as we don’t exactly know what causes it yet. Yet, there are some things you can do that might help lower the risk of developing this disease or lessen its impact if you do have it:

Genetic counseling: If your family has a history of Crohn’s disease, you can benefit from genetic counseling. This helps you to understand if you might develop the disease and discuss ways you could potentially prevent it or tests you could take to detect it early.

Watch for early symptoms and treat them: Keep an eye on symptoms such as ongoing stomach pain, diarrhea, bleeding while passing stools, unexplained weight loss, and tiredness. These may suggest you have Crohn’s disease, so seek medical help if you have these symptoms. Early treatment can help prevent further issues and lead to better long-term results.

Make changes to your diet: Although there isn’t a specific diet that has been proven to prevent Crohn’s disease, limiting sugar intake and staying away from foods that seem to trigger symptoms could help to avoid flare-ups.

Avoid environmental triggers: Certain aspects of the environment like cigarette smoke, air pollution, certain drugs like nonsteroidal anti-inflammatory drugs, and infections may make your symptoms worse or increase your likelihood of developing the disease, so these should be avoided.

In addition to these preventative measures, steps can be taken to prevent other health issues which are common in people with a Crohn’s disease diagnosis:

Adhere to medication: It’s important to stick to the treatment plan set by your doctor to manage symptoms, lessen inflammation, prevent a worsening of the disease, and decrease the risk of other problems.

Cancer screening: People suffering from Crohn’s disease are more prone to some types of cancer, including skin and gastrointestinal (digestive system) cancer. Regular screening can help to catch those cancers early and improve odds of successful treatment. For instance, a regular colonoscopy, once every one to three years, can help in early detection of colon cancer.

Prevent bone thinning: The medicine used for Crohn’s disease and possible lack of vitamins related to the disease can result in osteoporosis, or thinning of bones. Regular bone density checks help to detect osteoporosis early and manage it in a timely manner.

Prevent infections: The medications used for controlling Crohn’s disease can make the patient more prone to infections. Hence, vaccinations against lung infections caused by pathogens like pneumococcus, H influenzae, and influenza virus are recommended. Vaccination against other diseases might also be necessary, depending on the patient’s health condition and geographical location.

It’s important to note that the effectiveness of these measures might vary from person to person. Therefore, not every measure may work for everyone. More research needs to be done to understand the causes of Crohn’s disease and to find ways to more effectively prevent and treat it.