What is the primary care approach for a patient with a 6-week history of altered stools, characterized by urgency and soft stools, without changes in diet?

Primary Care Approach to 6-Week History of Soft Stools with Urgency

You should perform basic screening blood and stool tests now, then make a positive diagnosis of irritable bowel syndrome with diarrhea (IBS-D) if these tests are normal and no alarm features are present. 1

Initial Assessment and Red Flags

First, assess for alarm features that would mandate urgent gastroenterology referral and more aggressive investigation: 2, 3

• Unintentional weight loss 2, 3
• Rectal bleeding or positive fecal occult blood 1, 2
• Nocturnal diarrhea (waking from sleep to defecate) 2, 3
• Fever 2, 3
• Age >45 years with new-onset symptoms 2, 3
• Family history of colorectal cancer or inflammatory bowel disease 3

If any alarm features are present, refer to gastroenterology for colonoscopy. 1, 2

Required Baseline Investigations in Primary Care

Before making a diagnosis of IBS, you must complete these screening tests: 1

Blood Tests:

• Complete blood count (to exclude anemia) 1, 2
• C-reactive protein or erythrocyte sedimentation rate (to exclude inflammation) 1, 2
• Anti-tissue transglutaminase IgA with total IgA (to exclude celiac disease - this is mandatory) 1, 2, 3
• Thyroid function tests 2, 3

Stool Tests:

• Fecal calprotectin (mandatory in patients <45 years with diarrhea to exclude inflammatory bowel disease) 1, 2
• Fecal immunochemical test (FIT) for occult blood 2

Making a Positive Diagnosis of IBS

If investigations are normal and no alarm features exist, make a confident positive diagnosis of IBS based on symptoms alone. 1 The British Society of Gastroenterology recommends using the NICE definition rather than restrictive Rome criteria: abdominal pain or discomfort associated with altered bowel habit for at least 6 weeks, in the absence of alarm symptoms. 1

Key diagnostic features to confirm: 1

• Relationship between abdominal pain and bowel habit change (pain relieved or worsened by defecation, or temporally associated with diarrhea) 1
• Urgency and soft/loose stools 1
• Bloating (if present, highly suggestive of IBS) 1

Initial Management Strategy

Patient Education and Reassurance

Provide empathic explanation that validates the patient's symptoms as real and taken seriously. 1 Explain that IBS is a disorder of gut-brain interaction, not a psychological condition, and that there is no serious underlying disease. 1

Set realistic expectations: there is no cure for IBS, but treatments can significantly improve quality of life and are likely needed long-term. 1

First-Line Symptomatic Treatment

For diarrhea-predominant symptoms, start loperamide: 2

• Initial dose: 4 mg, then 2 mg after each unformed stool 2
• Average maintenance dose: 4-8 mg daily 2

Dietary Counseling

Recommend keeping a 2-week symptom and food diary to identify triggers. 1 Common dietary factors to address: 1, 4

• Excess caffeine or stimulants 1
• High intake of poorly absorbed sugars (fructose, sorbitol) 1, 4
• Fermentable carbohydrates (FODMAPs) 1, 4

Consider referral to a specialist gastroenterology dietitian for low FODMAP diet if symptoms are moderate to severe and patient is receptive. 1 However, avoid this in patients with eating disorders or severe mental illness. 1

When to Refer to Gastroenterology

Refer if: 1

• Diagnostic uncertainty persists after initial workup 1
• Symptoms are severe or refractory to first-line treatments 1
• Patient specifically requests specialist opinion 1
• Fecal calprotectin is elevated (≥250 μg/g warrants colonoscopy; 100-249 μg/g should be repeated off NSAIDs/PPIs) 1

Common Pitfalls to Avoid

• Do not make an IBS diagnosis without completing basic blood and stool screening first - this risks missing celiac disease, inflammatory bowel disease, or microscopic colitis 2
• Do not perform exhaustive investigations - focus on making an early positive diagnosis to facilitate treatment 1
• Do not dismiss the patient's concerns - lack of empathy and validation worsens outcomes 1
• Do not forget to screen for psychological comorbidities (depression, anxiety) which frequently coexist and may require concurrent management 1