Describe the general principles.
Management of CD is complex and includes medications with potentially significant adverse effects.
Tailor therapy to the severity of CD, phase of the disease (acute flare or remission), and risk of progression of CD.
Surgery may be required to manage complications and is an option for isolated short-segment disease.
Lifestyle modifications (e.g., smoking cessation) may decrease the incidence of complications.
Regular monitoring of disease activity and screening for complications are essential aspects of long-term management.
Used to manage acute flares.
Agents that have a rapid onset of action (e.g., corticosteroids, biologics) are used.
Used to maintain remission, typically in patients with moderate or severe CD and those at high risk of progression of CD. 
Biologics and immunomodulators are the principal agents of maintenance therapy.
Symptoms do not accurately correlate with disease activity. Use objective markers of disease severity (e.g., biomarkers, imaging, endoscopy) to assess the severity of CD, guide treatment, and verify remission.
Describe the use of corticosteroids.
Primarily used to induce remission
Agents used (depending on severity of CD):
Controlled ileal release budesonide
A formulation of the synthetic steroid budesonide that is released in environments with a pH ≥ 5.5, which facilitates drug delivery distal to the proximal small bowel
Used to treat Crohn disease that involves sites of inflammation in the ileum and/or ascending colon
Describe the use of biologics.
Anti-TNF-α antibodies: e.g., adalimumab, infliximab, certolizumab
Increasingly used as a primary agent to induce remission.
Also used to maintain remission and manage CD refractory to immunomodulators
Anti-leukocyte trafficking antibody (vedolizumab) and anti-p40 antibody (ustekinumab) : used mainly to induce and maintain remission in moderate to severe CD
Describe the use of immunomodulators.
e.g., thiopurine analogs (azathioprine, 6-mercaptopurine), methotrexate
Primarily used to maintain remission
Can be used as a steroid-sparing regimen to induce remission
Describe the use of 5-aminosalicylic acid derivative.
sulfasalazine (mesalamine is not routinely recommended)
May be considered to induce remission of mild to moderate colonic or ileocolonic CD
Not effective in isolated small bowel disease
Describe the supportive therapy.
Antidiarrheal therapy: loperamide OR cholestyramine
Stress, depression, and anxiety management
Enteral nutrition is preferred over parenteral nutrition.
Identify and treat micronutrient deficiency: Iron deficiency, vitamin D deficiency, and vitamin B12 deficiency are common.
Identify and treat malabsorption syndrome: E.g., supplement calories, protein, and micronutrients (vitamins, zinc, calcium, iron).
Poor pain control and/or increased opioid use may indicate inadequate disease management.
Antidiarrheals should not be used in patients with bowel obstruction, abdominal tenderness, or signs of systemic infection (e.g., fever).
Describe surgery as a treatment option.
Half of patients with CD require major abdominal surgery within 10 years of diagnosis.
Severe complications (e.g., bowel obstruction, intraabdominal abscess, perianal abscess)
Unsuccessful medical therapy
Symptom control in disease localized to a short segment of the bowel
Surgical drainage of abscess
Laparoscopic or open resection of the diseased bowel segment (small bowel resection, segmental colectomy)
Strictureplasty (bowel-sparing technique)
Surgery can lead to remission but is not curative, and short bowel syndrome may occur following multiple procedures.
Describe the long-term management.
Chronic inflammation increases the risk of intestinal cancer. 
Schedule surveillance colonoscopy with biopsies 
After 8 years after CD onset in patients with ≥ 30% colonic involvement.
At diagnosis in patients with primary sclerosing cholangitis
Anemia and malnutrition: e.g., CBC, iron-binding studies, folate, vitamin B12, LDH, vitamin D, albumin 
Osteoporosis: DXA in patients with > 3 months cumulative lifetime exposure to corticosteroids
List other DDs.
Noninfectious colitis (ischemic, after radiation therapy, after ingestion of drugs, etc.)
Irritable bowel syndrome
Malignant intestinal transformations