How Is Ulcerative Colitis Diagnosed?
Medically reviewed by Jay N. Yepuri, MD
A gastroenterologist (who specializes in bowel disease) can use endoscopic tests and biopsies to diagnose ulcerative colitis. Endoscopic tests include a colonoscopy or flexible sigmoidoscopy, according to StatPearls.
Ulcerative colitis is an inflammatory bowel disease (IBD) that causes irritation and sores in the lining of the colon and rectum (the last sections of the large intestine). The most common symptoms are diarrhea (with or without blood) and abdominal pain.
supersizer / Getty Images
Related: How Is Crohn’s Disease Diagnosed?
Medical History
The first step toward an ulcerative colitis diagnosis is collecting your medical history. A healthcare provider will ask about symptoms, timing, family history, and past health conditions. Some questions involve bowel habits and your sexual history. These questions may feel intrusive, but your answers can provide clues to help your provider rule out similar diseases.
Questions they may ask include:
Could you possibly have a sexually transmitted infection (STI)?
Did these symptoms come on suddenly or over time?
Do you ever have constipation?
Do you have any problems with your immune system?
Do you have blood or pus in your stool?
Do you have diarrhea?
Do you have pain or cramping in your abdomen?
Do you have rectal pain? (The rectum is the last part of the intestines, close to where stool exits the body)
Do you take over-the-counter (OTC) pain medications, such as Advil or Motrin (ibuprofen) and Bayer (aspirin)?
Have you ever had diarrhea that wakes you up at night?
Have you ever had radiation therapy?
Have you had strong urges (urgency) to have bowel movements after you’ve already emptied your bowels?
Have you recently stopped smoking?
Have you traveled out of the country recently?
How frequently do you experience urgency but cannot have a bowel movement?
How long have you had diarrhea?
How many times a day do you have diarrhea?
What medications do you take?
When was the last time you took antibiotics?
Diarrhea (with and without blood) and abdominal pain are the two most common ulcerative colitis symptoms. Onset is typically gradual and gets worse over time. A healthcare provider may suspect ulcerative colitis if you have chronic diarrhea that lasts over four weeks.
Physical Exam
The next step is typically a physical exam. A healthcare provider will look for a fever, low blood pressure, increased heart rate, abdominal tenderness, and malnutrition. They may perform a rectal exam to look for blood in your stool. Normal physical exam findings, however, do not rule out ulcerative colitis.
Lab Tests
Lab tests won't confirm ulcerative colitis, but they provide essential information and can help rule out similar diseases. Blood tests may include:
Albumin: Low blood levels of this protein may indicate malnutrition.
C-reactive protein (CRP) test: CRP is a protein made in the liver. A high CRP level indicates excess inflammation, a hallmark of ulcerative colitis.
Chemistry panel: A chemistry panel (chem 8 or chem 20) provides information about your electrolyte levels and whether you're dehydrated.
Complete blood count (CBC): This checks your red and white blood cells. A CBC provides clues about potential infections and blood loss.
Erythrocyte sedimentation rate (ESR): This test, like CRP, detects inflammation.
P-ANCA and ASCA: These tests look for specific antibodies and antigens to help differentiate ulcerative colitis from related conditions, such as Crohn's disease.
Polymerase chain reaction (PCR): This test detects the DNA or RNA (genetic material) of certain pathogens, or microorganisms that cause disease.
Stool samples can detect blood, infections, and fecal calprotectin levels, which provide clues about inflammation in the digestive tract. A healthcare provider may check your blood or genital fluid for STIs.
Colonoscopy
A colonoscopy is an endoscopic exam that visualizes the large intestine. A gastroenterologist inserts a small tube with a video camera into your rectum. This allows them to look for irritation, sores, or scar tissue on the lining of the rectum and colon.
Flexible Sigmoidoscopy
A flexible sigmoidoscopy is an endoscopic exam similar to a colonoscopy. The difference is that the tube does not go as far into the intestines. This test may replace a colonoscopy if you are severely sick or at risk for a potential complication called a toxic megacolon.
Biopsy
A biopsy is a sample of tissue sent to the lab for testing. A gastroenterologist will collect an intestinal sample for biopsy from several different areas of the colon during an endoscopic exam. The only way to definitively confirm ulcerative colitis is through endoscopic exams that include a biopsy.
Imaging
An ulcerative colitis diagnosis does not require imaging tests like X-rays, computerized tomography (CT), or a barium enema. A healthcare provider may order these tests to help rule out other diseases. Normal imaging results do not rule out or confirm ulcerative colitis.
Stages of Ulcerative Colitis
The diagnostic criteria for ulcerative colitis include a combination of these factors:
Chronic diarrhea for more than four weeks
Endoscopic findings (e.g., inflammation, sores, bleeding, vascular pattern, scar tissue)
Exclusion of other causes of colitis by history, lab work, and biopsy
Histology (biopsy findings)
A healthcare provider will also stage ulcerative colitis to note the extent and severity of the disease. Staging helps when planning treatment.
The Mayo Score
Healthcare providers use several different scoring systems to stage ulcerative colitis. The Mayo score is one of the most popular systems. This scoring system considers stool frequency, rectal bleeding, endoscopy findings, and a healthcare provider's global assessment. Global assessment refers to quality of life, discomfort, sense of well-being, and disability.
A healthcare provider will typically grade ulcerative from remission to severe as follows:
Remission: Free of symptoms
Mild: Fewer than four stools per day, with or without blood; no signs of systemic toxicity or inflammation; pain is minimal
Moderate: Frequent bloody diarrhea; more than four episodes per day; mild anemia, not requiring blood transfusion; minimal signs of toxicity, adequate nutrition, and mild weight loss
Severe: More than six episodes of bloody diarrhea per day; symptoms may include extreme pain, fever, elevated heart rate, anemia, malnutrition, weight loss, and an increased ESR
Healthcare providers also classify ulcerative colitis by the area of irritation and how far it spreads. These classifications include:
Left-sided colitis: Inflammation extends up the color to the left side of the body and around the spleen
Pancolitis: Inflammation in the whole colon
Proctosigmoiditis: Irritation in the rectum and sigmoid colon (lower end of the large intestines)
Ulcerative proctitis: Inflammation in the rectum
Screening for Related Conditions
A differential diagnosis means ruling out similar diseases. Crohn's disease is the most commonly mistaken for ulcerative colitis. Both ulcerative colitis and Crohn's disease are types of IBD.
These diseases occur in different areas of the digestive tract. Crohn's disease can affect any part of the digestive tract. Ulcerative colitis affects the colon and the rectum. These are the areas closest to the anus, where stool exits the body.
Healthcare providers will also consider the following health conditions:
Gastrointestinal (GI) infections
Other types of colitis (inflamed colon)
Some STIs, depending on symptoms
Toxic megacolon
Tuberculosis
Healthcare providers can exclude similar health conditions through a medical history, endoscopy, lab tests, and biopsies. A raised fecal calprotectin narrows the focus to IBD (ulcerative colitis or Crohn's disease). This test cannot differentiate ulcerative colitis from Crohn's since it does not show the location of the inflammation.
A healthcare provider may order these lab tests to differentiate ulcerative colitis from Crohn's disease:
ASCA: ASCAs are found in both types of IBD but are more prevalent in Crohn's disease.
P-ANCA: Sixty to 70% of those with ulcerative colitis have P-ANCA antibodies. P-ANCA can be present in some with Crohn's disease.
Comorbid Conditions
Comorbidities are other health conditions that may occur with a disease. A healthcare provider may screen you for these common comorbidities:
Cancer
Cardiovascular (heart and blood vessels) disease
Liver disease
Migraines or severe headaches
Respiratory (lung) disease
Related: What Is Celiac Disease?
A Quick Review
Ulcerative colitis is a type of inflammatory bowel disease, or IBD, that causes irritation and sores in the lining of the colon and rectum. After collecting your medical history, a gastroenterologist will use an endoscopic exam and biopsy to make a definitive diagnosis. They will also order tests and gather information to rule out similar diseases, like Crohn's disease, and screen for comorbidities, such as arthritis, cancer, and kidney disease.
If diagnosed, a healthcare provider will grade your ulcerative colitis as in remission, mild, moderate, and severe and classify it by the area of irritation and how far it spreads. These classifications include left-sided colitis, pancolitis, proctosigmoiditis, and ulcerative proctitis.
For more Health.com news, make sure to sign up for our newsletter!
Read the original article on Health.com.
