Crohn’s disease is a chronic inflammatory bowel disease (IBD) that causes inflammation anywhere along the digestive tract, from the mouth to the anus. While severe gastrointestinal distress is common, the disease is highly variable. It is possible to have Crohn’s disease and not know it, especially in the early stages, because inflammation can manifest subtly or be mistaken for more common, less serious issues.
The Spectrum of Crohn’s Severity
Crohn’s disease exists on a wide spectrum of severity that can change over time. Many people initially experience a mild, localized form, sometimes referred to as indolent disease, that causes little disruption. This low level of inflammation may not produce the classic, debilitating symptoms like severe abdominal pain or persistent diarrhea.
The disease is characterized by periods of active inflammation (flare-ups), interspersed with periods of remission where symptoms are minimal or absent. A person in clinical remission may feel perfectly healthy. However, symptomatic remission does not always mean the underlying inflammation has fully resolved, a condition known as mucosal healing or endoscopic remission.
Feeling well can create a disconnect between a patient’s perception of health and the actual disease activity. Without noticeable symptoms, low-level inflammation can still be present and cause damage. This variability and the existence of long, symptom-free periods are primary reasons why a diagnosis can be significantly delayed.
Subtle Signs That Mimic Other Conditions
Crohn’s is often missed in its early stages because initial signs are vague or easily attributed to everyday stress, diet, or other benign conditions like Irritable Bowel Syndrome (IBS). Chronic fatigue is one of the most common complaints, often dismissed as simply being tired. This fatigue is tied to the systemic inflammation and nutrient malabsorption caused by the disease.
Many manifestations occur outside the digestive tract, known as extraintestinal manifestations (EIMs), affecting 25% to 40% of patients. For example, intermittent joint pain (arthralgia) affects the large joints. This discomfort may be mistaken for a minor sports injury or early-onset arthritis.
Other subtle signs include mild anemia, often due to chronic blood loss or poor iron absorption, which contributes to low energy. The appearance of mouth sores (aphthous ulcers) can signal Crohn’s activity, though they are confused with common canker sores. Additionally, a persistent, unexplained low-grade fever, not tied to a cold or flu, can signal ongoing, silent inflammation.
Risks of Undiagnosed Disease Progression
Even when Crohn’s disease is mild or silent, the underlying inflammation continues to cause progressive, structural damage to the bowel wall. If left untreated, this can lead to serious complications that may require surgical intervention. One such complication is the formation of a stricture, a narrowing of the intestinal tract caused by the buildup of scar tissue.
Strictures can eventually lead to a bowel obstruction, where food or stool cannot pass through the intestine, causing severe abdominal pain and vomiting. Another serious complication is the development of fistulas. These are abnormal tunnel-like connections that burrow through the bowel wall to another organ (e.g., bladder, vagina, or skin). Fistulas affect about one in three people with Crohn’s.
Chronic inflammation also significantly impairs nutrient absorption, leading to deficiencies even in the absence of severe symptoms. Common deficiencies include Vitamin D (which can lead to bone loss and osteoporosis), and Vitamin B12 and iron (which contribute to anemia). Over time, sustained inflammation of the colon raises the risk for developing colorectal cancer, especially after having the disease for eight to ten years.
The Diagnostic Process
If a healthcare provider suspects Crohn’s disease based on subtle symptoms or a family history, a comprehensive diagnostic process is initiated to confirm the diagnosis and rule out other conditions. Initial steps typically involve non-invasive laboratory tests, including blood tests that check for markers of inflammation like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), as well as signs of anemia.
A stool test is commonly used to measure fecal calprotectin, a protein released by white blood cells into the bowel, which serves as a specific marker for inflammation within the gastrointestinal tract. To visualize the inflammation and assess the extent of the disease, an endoscopic procedure, such as a colonoscopy, is often performed. During this procedure, a flexible tube is inserted to examine the large intestine lining and take biopsies for analysis.
Finally, imaging studies are used to evaluate sections of the small intestine that are inaccessible by standard endoscopy and to look for complications like strictures or fistulas. These often include Magnetic Resonance Enterography (MRE) or Computed Tomography (CT) Enterography, which provide detailed images of the entire bowel wall. No single test confirms the diagnosis; a combination of these clinical, laboratory, and imaging results is required for a definitive diagnosis.