Crohn disease

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Crohn disease

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A 37-year-old woman with Crohn ileocolitis presents to the office because of urinary burning, urgency and frequency since yesterday. She also reports passage of air at the end of urination. Review of systems reveals fatigue, weight loss, and intermittent diarrhea. Past medical history is significant for 3 urinary tract infections in the past 6 months treated with antibiotics, as well as Crohn disease, for which she is currently taking 5-aminosalicylic acid. She does not smoke or drink alcohol. Temperature is 38.8°C (102°F), pulse is 103/min, respirations are 20/min, and blood pressure is 135/85 mmHg. Physical examination shows multiple aphthous ulcers on the oral mucosa and a mildly distended lower abdomen with tenderness. Urinalysis reveals brown-colored urine with positive nitrites. Serum creatinine is 0.9 mg/dL. Which of the following is the most likely cause of this patient’s symptoms?  

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Adalimumab p. 120, 497

for Crohn disease p. 389

Aphthous stomatitis

Crohn disease p. 389

Arthritis p. 472

Crohn disease p. 389

Azathioprine

for Crohn disease p. 389

Cholelithiasis p. 403

Crohn disease p. 389

Ciprofloxacin

for Crohn disease p. 389

Corticosteroids

Crohn disease p. 389

Crohn disease p. 389

azathioprine p. 118

BNaN deficiency p. 426

cholelithiasis and p. 403

as granulomatous disease p. NaN

lesions in p. 732

natalizumab p. 120

spondyloarthritis and p. 475

sulfasalazine for p. 407

vitamin BNaN deficiency p. 67

Infliximab p. 120, 497

for Crohn disease p. 389

Kidney stones p. 620

Crohn disease association p. 389

Metronidazole p. 192

for Crohn disease p. 389

Ulcers (gastrointestinal)

Crohn disease p. 389

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Crohn’s disease, now more frequently referred to as Crohn disease, is an inflammatory bowel disease that, well, causes inflammation of the bowel.

Unlike its cousin, ulcerative colitis, which only affects the large intestine, Crohn disease causes inflammation and tissue destruction anywhere along the gastrointestinal tract, from the mouth to the anus.

Although ulcerative colitis is classified and treated as an autoimmune disease, Crohn disease isn’t technically classified as an autoimmune disease, but rather an immune-related disorder...what does that mean exactly?

Well, with “auto” immune, we think that your own cells and proteins trigger the immune system to start attacking itself.

In Crohn disease, the immune system is thought to be triggered by some foreign pathogen in the gastrointestinal tract.

Several pathogens have been implicated, like Mycobacterium paratuberculosis as well Pseudomona and Listeria species.

So the immune system’s reacting to foreign pathogens...isn’t that what it’s supposed to be doing? Well, yes and no; yes because it’s targeting a foreign invader, no because the inflammatory response is large and uncontrolled and leads to destruction of the cells in the gastrointestinal tract.

So what’s thought to happen is one of these pathogens activates the immune system by antigen presentation, meaning one of the gastrointestinal cells is like “here, I think this is an infectious molecule”, and that’s fine, because it is.

At that point T helper cells, or Th1 cells swoop in and release cytokines—which are cell signaling molecules—like interferon-gamma, and tumor necrosis factor alpha, which further stimulate the inflammatory response.

The cytokines attract Inflammatory cells like macrophages which start releasing even more inflammatory substances like proteases, platelet activating factor, and free radicals, all which contribute to inflammation.

Although not definitively understood, it’s thought that for patients with Crohn disease, one of the steps in this process is dysfunctional and leads to an unregulated and out-of-control inflammatory response.

Sources

  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "Crohn's disease" The Lancet (2012)
  6. "Crohn’s Disease: an Immune Deficiency State" Clinical Reviews in Allergy & Immunology (2009)