Clinical Presentation
Irritable Bowel Syndrome_Initial Assesment 1Recurrent Abdominal Pain
The pain in irritable bowel syndrome is intermittent and the patient may describe the pain as crampy in nature with variable intensity and periodic exacerbations. The location and character of pain may vary, and defecation or passing of flatus often provides relief.
Altered Bowel Habits
Diarrhea, constipation, alternating diarrhea and constipation, or normal bowel habits alternating with either diarrhea and/or constipation may be noted in patients suspected with irritable bowel syndrome.
Other Gastrointestinal (GI) Symptoms
Gastroesophageal reflux, dysphagia, early satiety, intermittent dyspepsia, nausea, and non-cardiac chest pain are other gastrointestinal symptoms present in patients with irritable bowel syndrome.
Extraintestinal Symptoms
Extracolonic symptoms such as urinary frequency and urgency, sexual dysfunction, fibromyalgia, dyspareunia, poor sleep, menstrual difficulties, lower back pain, headaches, chronic fatigue, and insomnia may be noted. The more extracolonic symptoms present, the greater the likelihood of having severe irritable bowel syndrome.
History
Irritable Bowel Syndrome_Initial Assesment 2A careful history should include factors and medications that may mimic or exacerbate irritable bowel syndrome symptoms. Lactose, Sorbitol, magnesium-containing antacids, proton pump inhibitors, antibiotics, Metformin and Colchicine could cause diarrhea. Anticholinergics, calcium antagonists, diuretics, and opioids could cause constipation.
The features in the history that may be indicative of irritable bowel syndrome are symptoms started >6 months ago; are aggravated by stress; are aggravated by meals; frequent visits to the clinic due to abdominal problems without a clear diagnosis; symptoms that worsen with anxiety or depression; and with or without nausea, dyspepsia, and/or heartburn.
Physical Examination
The physical examinations of patients with irritable bowel syndrome are generally normal and should reveal no evidence of organic disease that is responsible for the patient's symptoms.
Abdominal Exam
The abdominal exam may reveal nonspecific tenderness in the left lower abdomen over the sigmoid colon. Abdominal distention may be present.
Rectal Exam
A rectal exam should exclude anorectal abnormalities. In patients with abnormal rectal examinations suggesting dyssynergia or those with refractory constipation unresponsive to conventional therapy and with symptoms of a pelvic floor disorder, anorectal physiology testing may be considered to identify patients who could benefit from biofeedback therapy.
Screening
Other Factors that May Lead the Clinician to Perform Routine Diagnostic Tests:
Other factors that may lead the clinician to perform routine diagnostic tests include a history of travel to locations with endemic parasitic diseases; a family history of inflammatory bowel disease; a relation to menstruation; the consumption of known foods that cause intolerance (especially milk), artificial sweeteners, dieting products, or alcohol; arthritis or skin findings on physical exam; signs or symptoms of malabsorption; and signs or symptoms of thyroid dysfunction.
Diagnosis or Diagnostic Criteria
There are no structural, biochemical, or physiological abnormalities that are demonstrated consistently in irritable bowel syndrome patients. Diagnosis is thus symptom-based, and therefore, an accurate history of the patient's symptoms is imperative. A positive diagnostic strategy is recommended compared to a diagnosis of exclusion in order to avoid unnecessary testing and reduce cost.
Symptom-Based Criteria for Diagnosis of Irritable Bowel Syndrome (Rome IV Criteria)
A recurrent abdominal pain for at least 1 day/week in the past 3 months with ≥2 of the following:
- Related to defecation
- Associated with change in stool frequency
- Associated with change in stool form (appearance)
The above criteria must be met for the past 3 months, with symptoms starting at least 6 months prior to diagnosis. A recent prospective study suggests that the upcoming Rome V criteria for diagnosing irritable bowel syndrome should focus more on pain instead of discomfort and consider modifying the abdominal pain requirement from once a week to 3 days per month.
Symptoms Cumulatively Supporting the Diagnosis of Irritable Bowel Syndrome
Symptoms cumulatively supporting the diagnosis of irritable bowel syndrome are bloating, abnormal stool frequency (>3x/day or <3x/week), abnormal stool form (hard/lumpy or mushy/watery), abnormal stool passage (straining, urgency, or feeling of incomplete evacuation), and passage of mucus.
The Rome criteria are reliable only when there is no other metabolic or organic explanation that would account for the patient's symptoms.
Subclassification of Irritable Bowel Syndrome (Rome IV Criteria)
- Irritable bowel syndrome with predominant diarrhea (IBS-D)
- Mushy or watery stools >25% of bowel movements (Bristol Stool Form Scale [BSFS] 6-7)
- Hard or lumpy stools <25% of bowel movements
- Irritable bowel syndrome with predominant constipation (IBS-C)
- Hard or lumpy stools >25% of bowel movements (BSFS 1-2)
- Mushy or watery stools <25% of bowel movements
- Irritable bowel syndrome with mixed bowel habits (IBS-M)
- Both hard or lumpy and mushy or watery stools >25% of bowel movements
- Irritable bowel syndrome unclassified (IBS-U)
- Diagnostic criteria for irritable bowel syndrome are met, but bowel habits cannot be classified into one of the three groups above. This may result from frequent changes in medications or diet or inability to discontinue medications affecting GI transit
Patients commonly transition between subclasses, at which diarrhea and constipation are commonly misinterpreted; thus, subclass clarification should be routinely performed. Patients who complain of “diarrhea” may refer to the frequent passing of formed stools. In some patients, “constipation” may refer to complaints associated with attempts at defecation and not lesser frequency of bowel movements.