Lower gastrointestinal symptoms – supporting earlier diagnosis

Specialist gastroenterology nurse Pearl Avery explains how nurses can use new diagnostic pathways to support earlier diagnosis and appropriate management in patients with lower gastrointestinal symptoms     

Diagnosis of gastrointestinal (GI) conditions is the UK is improving but unfortunately we are still seeing avoidable delays in diagnosis, due to stigma associated with symptoms, mixed knowledge and management of GI conditions, long waiting times for interventional diagnostics and multiple referral routes into specialist care.¹

The focus in NHS care is often on the red flags of cancer and of course this is essential. However, many symptoms of GI conditions overlap and it is crucial to explore diagnoses systematically.

NICE guidance on suspected cancer provides a clear framework on when and how to refer for GI signs and symptoms,² but once cancer is ruled out there has been much less clarity on how to investigate and diagnose more benign GI conditions, including but not limited to inflammatory bowel disease (IBD), coeliac disease and bile salt malabsorption.

These conditions place a significant burden on people when left undiagnosed, despite the importance of early diagnosis in improving patient outcomes. In particular, diagnostic delays in lower GI conditions, including IBD and coeliac disease, have significant implications for patient outcomes:³ studies have shown that delays in diagnosis are common in these conditions, which leads to worse disease progression and treatment outcomes.^4,5

Diagnosis of irritable bowel syndrome (IBS), which should be made once other conditions are excluded, can still be positively made using the Rome criteria, but may require a challenge if testing has not occurred.⁶ A proportion of patients with this diagnosis of IBS potentially have a treatable underlying cause.⁷  

A national primary care diagnostic pathway for lower GI symptoms

A new national resource for primary care healthcare professionals has recently been developed and is now available online on the dedicated website What’s up with my gut?⁸

The website provides clear direction for healthcare professionals, aiming to help patients get a diagnosis. Following the pathway can help shorten the diagnosis time, reduce variation among healthcare professionals and their teams and improve patient care experiences.

There are two pathways, one for adults and one for children, both available to download and display in your consulting room and covering:

• Considerations to make when taking a history.
• Possible presenting symptoms.
• Red flags for cancer.
• Conditions to consider.
• Investigations to consider.
• Referral pathways for secondary care.
• Safety netting.

The adult pathway has been endorsed by the Royal College of General Practitioners (RCGP), the Royal Pharmaceutical Society (RPS), the British Society of Gastroenterology (BSG) and the Royal College of Nursing (RCN). The paediatric pathway has received endorsement from the British Society of Paediatric Gastroenterology, Hepatology and Nutrition (BSPGHAN).

The project is a joint collaboration between the BSG, BSPGHAN, the Association of Coloproctology of Great Britain and Ireland (ACPGBI) and various charities including Coeliac UK and Guts UK, alongside a range of primary care healthcare professionals, including GPs and nurses, as well as individuals with lived experience.

Related Article: Supporting healthy childhood nutrition in primary care

What are the key points for nurses in primary care?

Each of the pathways is presented as a downloadable flow-chart with logical steps. The pathway supports access to local guidance and offers tips for standard screening investigations.

In summary, each step in the adult pathway covers:

1. Red flags for cancer (see Box 1).

Patients with red flags will require a faecal immunohistochemical test (FIT) to support an urgent referral for suspected colorectal cancer, or CA125 test for suspected ovarian cancer. Refer to guidelines for England, Wales, Scotland and Northern Ireland for specific requirements.

2. Common lower GI symptoms

The next step starts with the broad symptoms to consider in seeking a diagnosis. Common symptoms are:

• Change in bowel habit, for example, frequency, urgency, faecal incontinence, tenesmus.
• Abdominal pain, cramping, bloating, excessive wind.
• Rectal bleeding.

Symptoms may also include:

• Reduced appetite
• Nausea with or without vomiting
• Symptoms made worse with eating
• Persistent mouth ulcers
• Ongoing fatigue

At this stage, it is important to establish the duration of symptoms and history – in particular to rule out a self-limiting illness. If symptoms are of less than two weeks duration consider, eg, recent travel, changes in diet, alcohol, medications, an infection causing gastroenteritis, menstrual symptoms, possibility of haemorrhoids and fissures.

Consider a stool test to exclude infection (see also step 4 – investigations).

3. Conditions to think about

The pathway then prompts nurses to think which conditions may be relevant, and their characteristic features including potential distinguishing symptoms, for example:

• IBD. Often presents with diarrhoea, abdominal pain, rectal bleeding or weight loss, but may also present with symptoms in Box 1.

Presents at any age, but mainly at 18-35, with second peak in those aged 65 and over. Family history increases risk.

Potential distinguishing symptoms: Nocturnal defecation, fevers, recurrent/persistent anal abscesses, extra intestinal manifestations in joints, skin, eyes or perianal area.

• Coeliac disease. Occurs in 1 in 100 people and undiagnosed in two-thirds of cases. Can present in non-specific ways, including commons symptoms in Table 1.

Family history increases risk. More common in Down’s/Turner syndromes or history of autoimmune conditions like type 1 diabetes and thyroid disease; associated with iron deficiency anaemia or B12 or folate deficiency.

Potential distinguishing symptoms: Dermatitis herpetiformis, tooth enamel problems, reduced bone mineral density, unexplained fertility problems or repeated miscarriages, neurological problems such as unexplained ataxia or peripheral neuropathy.

• IBS. Longstanding illness with frequent abdominal discomfort and bowel symptoms that cannot be explained by any other disease.

Uncommon for people to present over the age of 50 for the first time.

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Abdominal pain or discomfort (present for at least 6 months) and relieved by defecation or associated with altered bowel frequency or stool form; straining, urgency or incomplete evacuation; abdominal bloating (particularly in women); passage of mucus.

4. Investigations to consider

The next step advises on appropriate lower GI investigations to support the initial history and clinical assessment.

Baseline blood tests include:

• Full Blood Count and Ferritin: looking for anaemia or infection or systemic inflammation.
• C-reactive protein (CRP): for inflammation and autoimmune disease.
• Coeliac screen. Advise patient not eliminate or reduce gluten in the diet.
• Thyroid function tests (TFTs): hyperthyroidism can cause diarrhoea, while hypothyroidism can cause constipation.
• Renal and liver function tests (LFTs) including albumin and calcium.

Stool tests

• Stool sample for infection (if not already excluded). Consider also parasites and specific requests for testing – eg, C difficile
• Faecal calprotectin and/or FIT to support diagnosis or exclusion of IBD.

(Note a negative FIT as part of the national bowel cancer screening programme does not mean a person with symptoms does not have colorectal cancer – the test used for screening the whole population [without symptoms] is less sensitive than that used for symptomatic patients.)

4. When to make a referral to a specialist

This step outlines when and where to refer based on investigation results.

In summary:

• If coeliac screen positive – refer to secondary care for diagnosis. If confirmed, this will involve treatment with a gluten-free diet in primary care, with dietetic support.
• If faecal calprotectin positive or FIT positive – refer to local pathway for next steps in diagnosis.
• If above ruled out, consider IBS – if baseline tests suggestive this should be diagnosed and treated in primary care.

5. Safety netting

Finally, the pathway emphasises the importance of safety netting – giving the patient permission to return if symptoms persist, and offering understanding of the impact of these symptoms.

Remember the GI tract is one long connected system of organs, and presenting symptoms could be related to upper GI conditions like bile salt malabsorption or upper GI cancer, and in women, gynaecological conditions including cancer, ovarian cysts, ectopic pregnancy and insidious hidden conditions such as endometriosis.

What should be considered with persistent symptoms:

• IBD or cancer should still be explored, even if stool tests were negative/normal.
• Upper GI cancer, eg, pancreatic or gastric.
• Non-site specific cancer.
• False-negative coeliac screen – eg, due to too little gluten in diet.
• Severe IBS symptoms may need GI referral.
• Other lower GI conditions, eg: microscopic colitis (if persistent watery diarrhoea, faecal calprotectin can be normal); bile acid malabsorption (common after cholecystectomy); diverticulitis; small bowel bacterial overgrowth; pancreatic insufficiency (causes weight loss, test for faecal elastase).

In summary…

Each pathway provides an easy-to-use, one-stop template that incorporates next steps beyond cancer diagnosis.

Related Article: CPD: Gastro-oesophageal reflux disease (GORD) in adults 

If integrated into daily practice, this will improve access to diagnosis and treatment, improving the quality of life for people living with often debilitating symptoms of lower GI conditions left undiagnosed.

Pearl Avery is a Consultant Nurse Practitioner in primary care with a specialist interest in gastroenterology and the lead for IBD nursing for Crohn’s & Colitis UK

References

1. Din S et al. Primary care diagnostic pathways for lower gastrointestinal symptoms. Lancet Gastroenterol Hepatol 2025 Jan;10(1):9-11
2. NICE. Suspected cancer: recognition and referral. [NG12] Last updated May 2025
3. Crohn’s and Colitis UK. Understanding diagnostic delays in Crohn’s and Colitis: an evidence review for Crohn’s and Colitis UK. 2022
4. Khalilipour B et al. Diagnostic delay in paediatric inflammatory bowel disease – a systematic investigation. J Clin Med 2022 Jul 18;11(14):4161
5. Cross E et al. Diagnostic delay in adult inflammatory bowel disease: A systematic review. Indian J Gastroenterol 2023 Feb;42(1):40-52
6. Black C. Review article: Diagnosis and investigation of irritable bowel syndrome. Aliment Pharmacol Ther 2021;54(Suppl 1):S33-S43
7. Goodory V et al. Validating simple modifications to the Rome IV criteria for the diagnosis of irritable bowel syndrome in secondary care. Aliment Pharmacol Ther2024; 61(2):354-62
8. Crohn’s and Colitis UK: What’s up with my gut?