Crohn's disease is a disorder of uncertain etiology that causes chronic inflammation in the gastrointestinal tract. While it was once thought to be an autoimmune disease, current research suggests the immune system may be attacking harmless bacteria or viruses in the gut, leading to inflammation and bowel injury. Genetics, immune system problems, and environmental factors are all believed to play a role in Crohn's disease, though none have been proven as the sole cause. Symptoms can vary but often include diarrhea, abdominal pain, weight loss, and bleeding, and in severe cases may lead to complications affecting other parts of the body. Diagnosis involves examinations, medical history, lab tests, and imaging to rule out other conditions and determine the affected areas.

1. Crohn's Disease
Abdulaziz Hamad Aldhlous
Abdulrahman Alqahtani

2. Crohn’s is a disorder of uncertain etiology.
It has often been thought of as an autoimmune disease but research suggests that
the chronic inflammation may not be due to the immune system attacking the body
itself, but rather a result of the immune system attacking harmless virus, bacteria or
food in the gut causing inflammation that leads to bowel injury.
Crohn's disease can cause other parts of the body to become inflamed (due to
chronic inflammatory activity) including the joints, eyes, mouth, and skin.

3. Although there are many theories about what causes Crohn's disease, none of them
have been proven.
There is a benefit, though, in understanding the possible causes of Crohn's
disease and how they interact with one another.
Doing so can help one better understand the symptoms, diagnosis, and treatment
of Crohn's disease.
Scientists believe that Crohn's disease is caused by a combination of these factors:
1-Immune system problems
2-Genetics
3-Environmental factors

4. How do immune system problems relate to Crohn's disease?
Scientists have linked immune system problems to inflammatory bowel disease (IBD), including
Crohn's. Usually, cells of the immune system defend the body from harmful microbes -- bacteria,
viruses, fungi, and other foreign substances -- that have entered it.
The body doesn't usually respond to all microbes, however. Many microbes are helpful, especially for
digestion.
And so the immune system leaves them alone.
If there is an invader that needs to be eliminated, your body's defense reaction begins.
This immune system response causes inflammation.

5. Is genetics connected to Crohn's disease?
Brothers, sisters, children, and parents of persons with IBD, including Crohn's disease, are slightly more likely
develop the disease themselves.
About 10% to 20% of people with Crohn's disease have at least one other family member who also has the
disease.
Is this tendency toward IBD and Crohn's disease passed genetically? Scientists have identified a gene
associated with Crohn's disease.
This gene helps the body decide how to react to certain microbes.
If the gene has changed or mutated in some way, your body's reaction to microbes may also be different
the normal reaction.
Over time, IBD or Crohn's disease may develop.
People with Crohn's disease have this mutated gene twice as often as people who do not have the disease.

6. Do environmental factors play a role in Crohn's disease?
Environmental factors may help trigger Crohn's disease.
Also, it should be noted that because a potential trigger is linked or associated
a condition does not mean that it causes it.
Associated environmental factors may include any of the following:
1-Substances from something you've eaten.
2-Microbes such as bacteria or viruses.
3-Cigarette smoke.
4-Other substances that are yet unknown.

7. What Are the Symptoms of Crohn's Disease?
Lots of people have stomach cramps with diarrhea or constipation.
It’s uncomfortable, but you usually get over it and forget about it.
But when you have these symptoms often, and they’re severe, there’s a chance you could have Crohn’s disease.
Symptoms
You may have:
1-Diarrhea.
2-Stomach pain.
3-Weight loss.
4-Bleeding from your rectum.
5-Constipation.
6-Fatigue.
7-Nausea.
8-Fever.
9-Sudden and frequent need to go to the bathroom.
You might not have all these.
The disease affects different people in different ways.
The symptoms can be mild, or they can leave you very weak.
At its worst, Crohn’s can cause severe complications.

8. The most serious cases of Crohn’s can cause:
1-Painful tears called fissures in the lining of the anus, mostly during bowel movements.
2-Fistulas (passages that form between loops of the intestine, or between the intestines and
the vagina, skin, or bladder).
3-Thickening of intestine walls, which makes it hard for food and waste to move
4-A partly or totally blocked intestine, for which you would need medical care right away.
5-Open sores called ulcers in the intestines, mouth, or anus.
6-Malnutrition.
7-Pain, swelling, and burning in other parts of your body, such as your skin, eyes, or joints.

9. There isn't any one test that can tell you whether or not you have Crohn's disease.
And Crohn's disease has many possible symptoms that are the same as symptoms for
other health problems.
So, to make a diagnosis of Crohn's disease, your doctor is likely to gather information
from multiple sources.
You'll probably go through a combination of exams, lab tests, and imaging studies
with these goals in mind:
1-Rule out other health problems that have similar symptoms.
2-Make a clear diagnosis of Crohn's disease.
3-Determine exactly which part of the digestive tract is affected.

10. Diagnosing Crohn's disease: Physical Exam and History:
Your doctor will begin by gathering information about your health history and
conducting a physical exam. Findings that may indicate further tests are needed
include:
1-Diarrhea, which may be bloody.
2-Family history of Crohn's disease.
3-Fever.
4-Pain in the abdomen.

11. Diagnosing Crohn's Disease: Lab Tests
Your doctor may request lab tests in order to look for any
problems that might be linked to Crohn's disease.
These tests check for signs of infection, inflammation, internal
bleeding, and low levels of substances such as iron, protein,
minerals.
Lab tests may include:
1-Blood protein levels.
2-Body mineral levels.
3-Red blood cell counts.
4-Stool samples to check for blood or infectious microbes.
5-White blood cell counts.

12. Diagnosing Crohn's Disease: CT Scans
CT scanning uses computer-aided X-ray
techniques to produce more detailed
of the abdomen and pelvis than can be
in traditional X-rays.
CT scans can help detect abscesses that
might not show up on other X-rays.