Ulcerative colitis

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Ulcerative colitis

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Questions

USMLE® Step 1 style questions USMLE

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A 32-year-old man comes to the office with complaints of pain in the hip joint and stiffness in the lower back for the past month. The symptoms are worse in the morning and improve with activity and exercise. Review of systems reveals intermittent abdominal pain and frequent episodes of small-volume bloody diarrhea for the last 3 months. He tried over-the-counter analgesics, which helped the joint pain but made the diarrhea worse. He does not have any pain with urination and has not traveled recently. The remainder of his history is noncontributory. Vitals are within normal limits. BMI is 22 kg/m2. Physical examination shows mild tenderness in the hip joints and limited spinal flexion. Laboratory analysis is shown below:

 
 Laboratory value  Results 
 Complete blood count 
 Hemoglobin  9.8 g/dL 
 Platelet count  460,000/mm3 
 Leukocyte count  8,000/mm3 

Plain radiographs show signs of sacroiliac joint inflammation. Which of the following is the most likely cause of this patient’s joint pain?  

External References

First Aid

2024

2023

2022

2021

Arthritis p. 472

ulcerative colitis p. 389

Bloody diarrhea p. 176

ulcerative colitis p. 389

Digestion

ulcerative colitis and p. 389

Infliximab p. 120, 497

for ulcerative colitis p. 389

ulcerative colitis p. 723

p-ANCA

ulcerative colitis p. 389

Primary sclerosing cholangitis p. 402

ulcerative colitis p. 389

Sclerosing cholangitis p. 400, 402

ulcerative colitis association p. 389

6-mercaptopurine p. 444

for ulcerative colitis p. 389

ulcerative colitis p. 723

Ulcerative colitis p. 389

autoantibody p. 113

spondyloarthritis p. 475

sulfasalazine for p. 407

treatment p. 723

Transcript

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Inflammatory bowel disease can cause inflammation in the small and large intestine, in other words...inflammation of the bowel.

Colitis refers specifically to inflammation in the colon, or the large intestine. Ulcerative colitis is a type of inflammatory bowel disease that tends to form ulcers along the inner-surface or lumen of the large intestine, including both the colon and the rectum.

These ulcers are spots in the mucosa where the tissue has eroded away and left behind open sores or breaks in the membrane.

Sometimes there is a flare which means that new damage has occurred, and then there are periods of remission when the tissue starts to heal up.

Ulcerative colitis is actually the most common type of inflammatory bowel disease, not that there are that many, but this one causes inflammation and ulcers in the mucosa and submucosa of the large intestine only, which is an important point that sets it apart from Crohn disease, another inflammatory bowel disease.

Now although certain environmental factors like diet and stress were once thought to be the culprit behind these ulcers forming in the gut, now it’s thought that these are more secondary, meaning they seem to make symptoms worse, but ulcerative colitis is now ultimately thought to be autoimmune in origin.

In fact, cytotoxic T cells from the immune system are often found in the epithelium lining the colon, so the thought is that inflammation and ulceration in the large intestine is caused by T cells destroying the cells lining the walls of the large intestine, leaving behind these eroded areas or ulcers.

It’s unclear what exactly these T cells are meant to be targeting though.

Some patients have p-ANCAs in their blood, or perinuclear antineutrophilic cytoplasmic antibodies, which are a kind of antibodies that target antigens in the body’s own neutrophils.

Although not completely understood, some theories suggest this may be partly due to an immune reaction to gut bacteria that have some structural similarity to our own cells, allowing antibodies to those gut bacteria, or p-ANCAs, to “cross-react” with neutrophils.

Summary

Ulcerative colitis is a type of inflammatory bowel disease that causes inflammation and ulcers in the mucosa and submucosa of the large intestine, specifically in the colon and rectum. The cause of the disease is believed to be autoimmune in origin, with cytotoxic T cells destroying the cells lining the walls of the large intestine, leaving behind eroded areas or ulcers. Environmental stimuli and genetic predisposition also play a role. Diagnosis typically requires colonoscopy and radiological imaging. Treatment includes anti-inflammatory medications, drugs that suppress the immune system, and biologic treatments. In severe cases, colectomy may be necessary.