Crohn Disease

Welcome to today’s episode where we’re diving into Crohn disease, exploring its symptoms, diagnosis, risk factors, treatment options, and potential complications. 

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Transcript

Welcome to today’s episode of AudioBoards. In this session, we’re discussing Crohn disease, a condition that most commonly affects the small bowel, particularly the terminal ileum and some adjacent parts of the proximal ascending colon. Crohn’s can also present as perianal disease, including fistulas, fissures, and abscesses and less than 5% of patients have symptomatic involvement of the upper intestinal tract. Crohn disease is a transmural process resulting in mucosal inflammation, ulceration, stricturing, fistula development, and abscess formation.

Cigarette smoking is strongly associated with the development of Crohn disease, resistance to medical therapy, and early disease relapse. 

When assessing a patient, it’s essential to ask about symptoms like fevers, weight loss, abdominal pain, how many liquid bowel movements they have each day, their general sense of well-being, and any prior surgical resections. During physical examination, focus on the patient’s temperature, weight, and nutritional status. Check for abdominal tenderness or any masses. A rectal examination is important, and be sure to look for extraintestinal manifestations of the disease.

Luminal inflammatory disease is the most common presentation at diagnosis. Patients will often report malaise, weight loss, and a loss of energy. In patients with ileitis or ileocolitis, diarrhea is common, typically non-bloody and often intermittent. However, if the rectum or left colon is affected, patients may experience bloody diarrhea and fecal urgency, which can mimic symptoms of ulcerative colitis. Cramping or steady right lower quadrant or periumbilical pain is also common, and physical examination may reveal focal tenderness, usually in the right lower quadrant. A palpable, tender mass—representing thickened or matted loops of inflamed intestine—may be present.

If a patient has an intestinal stricture, they may report symptoms like postprandial bloating, cramping pains, and loud borborygmi. In addition, sinus tracts can penetrate through the bowel and may be contained or form fistulas to adjacent structures. If penetration occurs, it can lead to an intra-abdominal or retroperitoneal abscess or phlegmon, presenting with fevers, chills, a tender abdominal mass, and leukocytosis.

Fistulas can form between the small intestine and colon, which may result in diarrhea, weight loss, bacterial overgrowth, and malnutrition. If the fistula connects to the bladder, recurrent infections may occur, and if it reaches the vagina, there may be malodorous drainage.

Perianal disease presents as large, painful skin tags, anal fissures, perianal abscesses, and fistulas. Extraintestinal manifestations include arthralgias, arthritis, iritis or uveitis, pyoderma gangrenosum, and erythema nodosum. Oral aphthous lesions are also quite common.

CBC and serum albumin should be obtained for all patients. Anemia may indicate chronic inflammation, mucosal blood loss, iron deficiency, or vitamin B12 malabsorption. Lab Work is significant for leukocytosis, hypoalbuminemia, and an elevated ESR or CRP. One of the best non-invasive tests is fecal calprotectin, which correlates with active inflammation. Stool specimens should also be examined for routine pathogens and C. difficile.

A colonoscopy is typically performed first to evaluate the colon and terminal ileum, as well as to obtain mucosal biopsies. It typically shows aphthoid, linear, or stellate ulcers, strictures, and segmental involvement, with areas of normal-appearing mucosa adjacent to inflamed areas. If small bowel involvement is suspected, CT or M.R enterography is obtained. Capsule imaging is also an option.

When making a differential diagnosis, remember that chronic cramping abdominal pain and diarrhea can also be symptoms of Irritable Bowel Syndrome or IBS and Crohn disease, though radiographic exams will be normal in IBS. Other conditions to consider include celiac disease, appendicitis, Yersinia enterocolitica enteritis, intestinal lymphoma, or undiagnosed AIDS. In tuberculosis-endemic areas, distinguishing active intestinal tuberculosis from Crohn disease can be challenging. NSAIDs can also exacerbate IBD and may cause NSAID-induced colitis.

Risk factors for an aggressive disease course include: Young age at disease onset, Early need for corticosteroids, Perianal disease, fistulizing or stricturing disease, or upper GI involvement, Laboratory markers of severe inflammation, such as low albumin or hemoglobin, elevated CRP, or elevated fecal calprotectin and Endoscopic findings of deep ulcerations.

Patients with mild disease have symptoms like minimal weight loss, normal or mildly elevated inflammatory markers, and no significant intestinal complications. Treatment for these patients should focus on a well-balanced diet, as few restrictions as possible, and fluid intake to avoid dehydration. Loperamide may be given for diarrhea as needed. For those with terminal ileum or ascending colon involvement, extended-release budesonide is given for 8 weeks. If remission is achieved, budesonide is tapered over 2-4 weeks, and the patient is observed. 5-Aminosalicylic Acid or ASA agents may also be used.

For those with left-sided or diffuse colon involvement, oral corticosteroids are given once daily for 1-2 weeks, followed by tapering over 4-8 weeks in patients who respond. If successful, sulfasalazine may be continued for long-term maintenance.

In patients who respond to initial therapy with budesonide or prednisone, treatment should be discontinued, and periodic monitoring for disease recurrence should occur every 1-2 years. Patients who respond to sulfasalazine or other 5-ASA formulations should continue long-term maintenance therapy. Those who either don’t respond to initial therapy or experience symptom relapse more than once every 1-2 years after tapering corticosteroids should be considered for moderate to high risk of disease progression and may be “stepped up” to more potent therapies.

For moderate to severe or high-risk Crohn disease, early treatment with biologic agents is recommended.Nutrition management involves a low-roughage diet—that is, no raw fruits, vegetables, or nuts. Total parenteral nutrition may sometimes be used short-term in patients with active disease. Parenteral vitamin B12 and oral vitamin D supplementation are also recommended. Involvement of the terminal ileum or prior ileal resection can reduce bile acid absorption, leading to secretory diarrhea from the colon. Treatment for this involves cholestyramine, colestipol, or colesevelam. 

Patients with extensive ileal disease may develop severe bile salt malabsorption and steatorrhea, in which case a low-fat diet is advised and Bile salt–binding agents should be avoided in these patients as they can exacerbate diarrhea. Small intestinal bacterial overgrowth is a common risk, and these patients may benefit from a course of broad-spectrum antibiotics.

Due to the rapid onset, corticosteroids are frequently used to achieve early symptomatic improvement in patients with moderate to severe disease. However, if a palpable inflammatory abdominal mass is present, a CT should be done first to rule out an abscess. If no abscess is found, parenteral corticosteroids should be administered. For outpatients with moderate to severe disease, oral prednisone or methylprednisolone is given for 1-2 weeks, followed by tapering over 4-8 weeks. During tapering, it’s recommended to start a biologic agent to prevent flare-ups. If needed, long-term treatment with an immunomodulator like azathioprine, mercaptopurine, or methotrexate can be considered.

Induction therapy with a biologic agent is recommended for almost all patients with moderate to severe Crohn disease. Current options include anti-TNF monoclonal antibodies like infliximab, adalimumab, and certolizumab pegol. Combination therapy with immunomodulators has shown improved efficacy. Ustekinumab, vedolizumab, and risankizumab are also options for patients who have failed anti-TNF therapy. When starting biologic therapy, patients should be evaluated for latent TB and other opportunistic infections.

Surgical interventions are indicated for patients who do not respond to medical treatment, or for those with complications like abscess formation, severe bleeding, intestinal obstruction, or perforation. The main surgeries are bowel resection or stricturoplasty, which can provide long-term symptom relief.

Common complications include abscess formation. Smaller abscesses less than 3 cm are managed with antibiotics, but larger abscesses may require surgical drainage. Small bowel obstructions should be treated with IV fluids and nasogastric suction. If the obstruction is due to active disease, corticosteroids may help. If conservative management fails, surgical intervention may be required.

Abdominal fistulas and rectovaginal fistulas are often treated with anti-TNF agents to close the fistulas, but relapses are common. Surgical drainage is also frequently needed. For anorectal abscesses, surgery is required, but only after optimizing medical therapy. Perianal abscesses require proper peri-anal care, such as sitz baths and moisture management with perianal pads.

Due to the risk of colon cancer in patients with long-standing Crohn colitis, annual colonoscopies are recommended after eight years of diagnosis. Patients who have undergone surgical resections may also experience malabsorption, particularly of vitamin B12.

That’s all for today’s episode. Thanks for listening to AudioBoards. Stay tuned for more educational content in our next episode! The views and opinions expressed on the AudioBoards Podcast do not necessarily reflect those of our employers. This podcast is for educational purposes only and should not be used to diagnose or treat any medical conditions. It is not a substitute for professional medical advice. Always consult a qualified, board-certified healthcare provider for any medical concern.