An Update on Inflammatory Bowel Disease

Key points

Epidemiology

Both UC and CD have similar ages of onset with peak incidence in the second to fourth decade and no significant gender prevalence.⁴ The incidence and prevalence of IBD is increasing worldwide but is highest in westernized areas.⁴ Data surrounding race and ethnicity are sparse, showing the highest incidence in white and Jewish people, but a more recent increase in Asian and Hispanic populations.⁵ A recent systematic review reported the highest annual incidence of UC in North America as 19.2 per

Pathogenesis

Although the pathogenesis of both UC and CD is still unclear, the resulting bowel inflammation seems to be due to dysregulation of the immune system in response to changes in commensal (nonpathogenic) gut flora.¹² Genetic studies have shown that host-microbe interactions serve a prominent role in the pathogenesis of both UC and CD and involve genomic regions that regulate microbial defense and intestinal inflammation.¹³

Clinical course and prognosis

In both UC and CD, the typical course is recurrent flares and remissions, but stable patients more often remain stable (a patient with clinically inactive disease has an 80%–90% probability to remain so in the following year), and those with flares more frequently relapse (a patient with clinically active disease has a 70%–80% possibility of relapse the following year).

Most patients with UC have mild to moderate symptoms at the time of diagnosis.¹⁴ Having an interval of less than 2 years from

Extraintestinal manifestations

Both UC and CD cause extraintestinal manifestations, seen in 25% to 40% of patients with IBD patients (Table 1).²⁰ Almost every organ system can be affected, but symptoms involving the eyes, skin, liver, and joints are considered primary manifestations. Having one extraintestinal manifestation increases the risk of developing another.²¹ Symptoms often parallel disease activity and many of them, such as peripheral arthritis, erythema nodosum, and episcleritis, respond to the treatment of the

Diagnosis

A 32-year-old woman presents to your office with 14 days of blood in her stools. It started with mild loose stools and has progressed over the 2 weeks to include frank blood and mucous. She describes cramps and urgency of stool. She denies abdominal pain. She describes fatigue but no fever. She does not smoke. She has no history of bowel issues and has not been recently on antibiotics.

The preceding clinical vignette highlights the difficulty in the clinical differentiation of CD, UC, and other

Treatment

IBD is not curable. Treatment goals are to minimize symptoms, improve quality of life, and minimize progression and complications of disease. The potential negative consequences of toxic immunosuppressive and anti-inflammatory drugs must be considered in treatment decisions.

Although diagnosis of CD versus UC follows a similar pathway, treatment of these diseases differs significantly and is considered individually.

Living with inflammatory bowel disease

Considerations beyond pharmacologic treatment are important in remission therapy for both diseases. These include smoking cessation, vaccinations (hepatitis B, influenza, pneumococcus, varicella, human papilloma virus),⁹¹ osteoporosis screening, psychological stress, anemia, and colon cancer surveillance for patients with extensive colon burden of disease.

UC and CD are both lifelong conditions with impacts on quality of life, which the primary care physician should assess and address in the

Collaborative care

Given the complexity of care for patients with IBD and the fact that these are lifelong conditions, a multidisciplinary team of providers is important to help the primary care provider provide holistic care to patients with IBD. A primary care provider can work with a gastroenterologist who can assist with diagnosis and treatment decisions. A dietician or nutritionist may be especially important in the care of pediatric and elderly patients. Referral to a perinatal specialist can be helpful for