📋 Key Information Summary
- Inflammatory bowel disease (IBD) encompasses Crohn's disease (CD) and ulcerative colitis (UC), with an estimated 85 000 Australians affected and rising incidence, particularly in paediatric and adolescent populations.
- Key clinical features suggesting IBD include chronic diarrhoea (>4 weeks), rectal bleeding, unintentional weight loss, nocturnal symptoms, and extraintestinal manifestations (arthritis, erythema nodosum, uveitis, oral aphthae).
- Red-flag features requiring urgent gastroenterology referral: significant or ongoing rectal bleeding, weight loss >5%, systemic symptoms (fever, tachycardia), iron-deficiency anaemia, suspected stricture or abscess, and failure of empirical therapy.
- First-line investigations in primary care include full blood count (FBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), faecal calprotectin, basic metabolic profile, liver function tests, iron studies, and stool microscopy/culture to exclude infection.
- Faecal calprotectin ≥250 µg/g in adults strongly suggests mucosal inflammation and warrants specialist referral; values of 50–249 µg/g require clinical correlation and repeat testing.
- Always exclude infectious causes of diarrhoea (Clostridioides difficile, Salmonella, Shigella, Campylobacter, parasites) before attributing symptoms to IBD.
- Avoid NSAIDs in suspected or confirmed IBD — they are associated with disease flares, GI ulceration, and IBD-related hospitalisation.
- Patients with significant bleeding, weight loss, systemic symptoms, or markers of inflammation should be referred as urgent (ideally seen within 2–4 weeks); those with milder or indolent presentations may be referred routinely.
- Interim management includes aggressive hydration, nutritional optimisation with dietitian input, iron supplementation (oral or IV) for iron-deficiency anaemia, and symptom control with loperamide only when infection has been excluded and colitis is not severe.
- Aboriginal and Torres Strait Islander Australians may present later with more aggressive disease; culturally safe care, point-of-care testing in remote communities, and engagement with Indigenous health workers are essential.
- Pregnant patients with suspected IBD require urgent referral as untreated active disease carries greater fetal risks than appropriate treatment; paediatric patients (especially <6 years) should be referred to paediatric gastroenterology.
- Definitive diagnosis requires ileocolonoscopy with biopsies and small-bowel imaging (MRI enterography); primary care role is recognition, initial workup, and timely referral — not endoscopic diagnosis.
Introduction & Australian Epidemiology
Inflammatory bowel disease (IBD) is a chronic, relapsing–remitting inflammatory condition of the gastrointestinal tract comprising two principal entities: Crohn's disease (CD) and ulcerative colitis (UC). A minority of patients (approximately 10–15%) are classified as IBD-unclassified (IBD-U) when colonic disease cannot be confidently categorised. IBD arises from a dysregulated immune response to gut microbiota in genetically susceptible individuals, modulated by environmental factors including diet, smoking, antibiotic exposure, and early-life events.
In Australia, IBD is a significant and growing health burden. Current estimates suggest approximately 85 000–100 000 Australians live with IBD, with the highest incidence and prevalence rates recorded in the Southern Hemisphere and comparable to Northern Europe and North America. Key Australian epidemiological data include:
- Incidence: Approximately 24–30 per 100 000 population per year for UC and 15–17 per 100 000 for CD.
- Prevalence: Estimated 0.4–0.7% of the Australian population, with projections suggesting continued increases over the coming decades.
- Age of onset: Bimodal, with a primary peak between ages 15–30 and a smaller secondary peak between 50–70 years. Paediatric-onset IBD (≤17 years) accounts for approximately 20–25% of new diagnoses.
- Geographic variation: Higher incidence in urban compared with rural settings; increasing incidence noted in migrants from low-prevalence regions after settling in Australia, supporting environmental triggers.
- Aboriginal and Torres Strait Islander Australians: Historically considered to have lower IBD rates, but emerging data suggest rising incidence and potential under-diagnosis due to healthcare access barriers, with later presentation and more complicated disease at diagnosis in some cohorts.
- Economic burden: The total annual cost of IBD in Australia has been estimated at over .7 billion, including direct healthcare costs, productivity losses, and carer burden (Crohn's & Colitis Australia, 2022).
The diagnosis of IBD is confirmed by specialist assessment including endoscopy with histopathology and cross-sectional imaging. However, the critical first step occurs in primary care — recognising suggestive clinical features, performing appropriate initial investigations, excluding infectious mimics, and initiating timely referral. Early diagnosis and treatment improve long-term outcomes, reduce complication rates (strictures, abscesses, fistulae in CD; toxic megacolon in UC), and decrease the need for surgery.
Diagnostic delay matters: Studies from Australian tertiary centres show that diagnostic delay >12 months in Crohn's disease is independently associated with higher rates of stricturing and penetrating complications. Primary care recognition and timely referral are pivotal.
Clinical Features Suggesting IBD
IBD should be considered in any patient presenting with chronic or recurrent gastrointestinal symptoms, particularly when the clinical picture extends beyond simple functional bowel complaints. The clinical features differ somewhat between UC and CD but overlap significantly. A high index of suspicion is required, especially in younger patients with multiple symptom domains.
Core Gastrointestinal Symptoms
| Symptom | Crohn's Disease | Ulcerative Colitis | Clinical Significance |
|---|---|---|---|
| Chronic diarrhoea | Watery or loose; often with crampy abdominal pain | Frequent, small-volume, often bloody | >4 weeks duration warrants investigation; nocturnal diarrhoea is particularly suggestive of organic disease |
| Rectal bleeding | Less common unless colonic involvement | Present in >90% at diagnosis; hallmark feature | Any rectal bleeding >2 weeks or recurrent should prompt IBD screening; always consider and exclude colorectal malignancy in patients >40 years |
| Abdominal pain | Right iliac fossa most common; colicky, post-prandial | Diffuse or left-sided cramping; improves with defecation | Constant or severe pain may indicate stricture, abscess, or perforation — urgent evaluation |
| Weight loss | Common; reflects malabsorption and systemic inflammation | Less prominent unless severe disease | Unintentional weight loss >5% over 3–6 months is a red flag |
| Nocturnal symptoms | Nocturnal pain, waking to defecate | Nocturnal diarrhoea, urgency | Highly suggestive of organic pathology; functional disorders (IBS) rarely cause true nocturnal waking |
| Tenesmus / urgency | If rectal or perianal disease present | Very common with proctitis or left-sided colitis | Impacts quality of life significantly; indicates active mucosal inflammation |
| Perianal disease | Fissures, fistulae, abscesses, skin tags (25–35% at diagnosis) | Rare | Perianal disease in a young patient with diarrhoea is strongly suggestive of Crohn's disease |
Extraintestinal Manifestations (EIMs)
Extraintestinal manifestations occur in 25–40% of IBD patients and may precede, coincide with, or occur independently of gastrointestinal symptoms. Recognition of EIMs is important as they may be the presenting feature that prompts IBD investigation.
Musculoskeletal
Arthralgia & Arthritis
Most common EIM (20–30%). Peripheral large-joint pauciarticular arthritis tracks with disease activity. Axial spondyloarthropathy (ankylosing spondylitis, sacroiliitis) may run an independent course.
Consider: HLA-B27, sacroiliac joint imaging if back pain present
Dermatological
Erythema Nodosum & Pyoderma Gangrenosum
Erythema nodosum (tender red nodules on shins) tracks with disease activity. Pyoderma gangrenosum (deep ulcers, often on lower limbs) can occur independently and requires urgent dermatology input.
Referral: Dermatology if pyoderma gangrenosum suspected
Ocular
Uveitis, Episcleritis, Scleritis
Uveitis (pain, photophobia, visual changes) is a sight-threatening emergency requiring same-day ophthalmology review. Episcleritis is usually self-limiting and tracks with disease activity.
Urgent: Ophthalmology referral within 24 hours for uveitis
Perianal disease as the presenting feature: A young adult presenting with recurrent perianal abscesses or fistulae-in-ano should be evaluated for underlying Crohn's disease. Up to one-third of CD patients have perianal disease at some point, and it may be the initial manifestation before intestinal symptoms appear.
Features Distinguishing IBD from Irritable Bowel Syndrome (IBS)
IBS is far more prevalent than IBD in Australian primary care (~15% of the adult population). Overlap exists, but certain features favour organic disease:
- Any rectal bleeding (IBS does not cause bleeding)
- Nocturnal diarrhoea or pain waking the patient from sleep
- Unintentional weight loss
- Fever or systemic symptoms
- Iron-deficiency anaemia
- Elevated inflammatory markers (CRP, ESR, faecal calprotectin)
- Family history of IBD
- Extraintestinal manifestations (arthritis, skin lesions, eye inflammation)
- Onset after age 50 (IBS more likely to present before age 40)
Never dismiss rectal bleeding as haemorrhoids without investigation. In patients >40 years or with any red-flag features, exclude colorectal cancer and IBD with appropriate testing and referral. Faecal occult blood testing alone is insufficient to rule out IBD.
Initial Primary Care Workup
When IBD is clinically suspected based on history and examination, a structured initial workup in primary care serves three purposes: (1) objectively assess for systemic and mucosal inflammation, (2) exclude infectious and other causes of symptoms, and (3) provide baseline data for the receiving specialist. Importantly, the primary care workup does not aim to confirm IBD — definitive diagnosis requires endoscopy and histopathology.
Recommended Investigations
Essential
Full Blood Count (FBC)
Microcytic anaemia (low Hb, low MCV, low ferritin) suggests chronic GI blood loss or iron malabsorption. Normocytic anaemia of chronic disease may coexist. Thrombocytosis may reflect systemic inflammation. Leucocytosis suggests active inflammation or infection. MBS item 66551.
Essential
C-Reactive Protein (CRP) & Erythrocyte Sedimentation Rate (ESR)
CRP >5 mg/L and/or ESR >20 mm/hr support active inflammation. CRP has higher specificity; ESR may be elevated independently of disease activity. Normal CRP does not exclude IBD — up to 20% of CD patients with active disease have normal CRP, particularly with isolated ileal or perianal disease. MBS item 66552.
Essential
Faecal Calprotectin
A neutrophil-derived protein measured in stool that reflects intestinal mucosal inflammation. The single most useful non-invasive test for distinguishing IBD from IBS in primary care. Values <50 µg/g in adults make active IBD unlikely (NPV ~99%). Values 50–249 µg/g are intermediate — repeat in 4–6 weeks. Values ≥250 µg/g are highly suggestive of IBD (PPV ~80–90%) and warrant urgent specialist referral. False positives occur with NSAIDs, PPIs, GI infections, and colorectal malignancy. MBS item 69234.
Essential
Stool Microscopy, Culture & Sensitivity
Must exclude infectious colitis before attributing symptoms to IBD. Request bacterial culture (Salmonella, Shigella, Campylobacter, Yersinia), ova and parasites, and C. difficile toxin (PCR or GDH + toxin EIA). Acute bloody diarrhoea with fever requires urgent stool MCS. MBS item 69300.
Available
Basic Metabolic Profile (Urea, Electrolytes, Creatinine)
Assesses for dehydration and renal function, particularly relevant in patients with significant diarrhoea. Establishes baseline before potential nephrotoxic therapies (e.g., 5-ASA agents). MBS item 66515.
Available
Liver Function Tests (LFTs)
Elevated ALP/GGT may indicate primary sclerosing cholangitis (PSC), which coexists with UC in 3–5% of patients. Establishes baseline before hepatotoxic medications (azathioprine, methotrexate). MBS item 66515.
Available
Iron Studies (Ferritin, Iron, Transferrin Saturation)
Iron-deficiency anaemia (low ferritin <30 µg/L, low transferrin saturation <20%) is present in 30–60% of IBD patients at diagnosis. Functional iron deficiency (ferritin 30–100 µg/L with low TSAT) may occur with chronic inflammation. Guides need for iron supplementation pre-referral. MBS item 66548.
Available
Vitamin B12 & Folate
B12 deficiency may occur with ileal Crohn's disease (site of B12 absorption). Folate deficiency may reflect malnutrition or methotrexate-related deficiency. Assess if CD is suspected or if there is macrocytic anaemia. MBS item 66548.
Additional Investigations to Consider
- Coeliac serology (anti-tTG IgA + total IgA): Consider if CD is suspected or the patient has features of malabsorption; coeliac disease and IBD can coexist. Available in Australian laboratories; MBS item 66570.
- Thyroid function tests (TSH): To exclude hyperthyroidism as a cause of diarrhoea, particularly in younger women.
- HIV testing: If risk factors present or chronic diarrhoea remains unexplained; chronic diarrhoea may be an initial presentation of HIV enteropathy.
- Abdominal X-ray: May show dilated loops, faecal loading, or exclude toxic megacolon (colonic diameter >6 cm with systemic toxicity). Useful in acute presentations with significant abdominal pain. MBS item 57905.
Investigations Not Recommended at Primary Care Stage
- CT abdomen/pelvis: Not a first-line investigation for suspected IBD. Reserved for specialist-guided assessment of complications (abscess, stricture, fistula). Exposes to radiation; MRI enterography is preferred in younger patients.
- Colonoscopy in primary care: Should be performed by or arranged through a gastroenterologist. Primary care clinicians should not independently request endoscopy for IBD suspicion — referral to a gastroenterologist allows appropriate endoscopic planning with biopsies.
- pANCA and ASCA serology: Limited utility in primary care; sensitivity and specificity are insufficient for diagnostic purposes. May be requested by specialists in indeterminate cases.
Faecal calprotectin testing in Australian general practice: Faecal calprotectin is funded under Medicare (MBS item 69234) and is widely available through major Australian pathology providers (Sullivan Nicolaides, Douglass Hanly Moir, Clinical Labs, Laverty). Results are typically available within 3–5 business days. Provide the patient with a specimen container and request form at the consultation to avoid delay.
Urgent vs Routine Referral
All patients with suspected IBD require gastroenterology assessment for definitive diagnosis and management planning. The urgency of referral is determined by the clinical severity, laboratory findings, and presence of red-flag features. Accurate triage ensures that patients with aggressive or complicated disease are seen promptly, while those with milder presentations are assessed within an appropriate timeframe.
Urgent Referral
Target: Specialist Review Within 2–4 Weeks
- Significant or ongoing rectal bleeding
- Unintentional weight loss >5%
- Systemic features: fever >38°C, tachycardia, signs of sepsis
- Iron-deficiency anaemia (Hb <100 g/L or symptomatic)
- Faecal calprotectin ≥500 µg/g
- Significantly elevated CRP (>50 mg/L) with GI symptoms
- Suspected perianal fistula or abscess
- Clinical suspicion of stricture (crampy post-prandial pain, vomiting, distension)
- Young patient (<16 years) with suspected IBD
- Failure of empirical treatment with persistent symptoms >4–6 weeks
Action: Fax or electronic referral to gastroenterologist; call specialist rooms directly if available; consider ED if acute deterioration
Routine Referral
Target: Specialist Review Within 4–8 Weeks
- Mild, intermittent symptoms without alarm features
- Faecal calprotectin 50–249 µg/g (borderline) with mild symptoms
- Mildly elevated CRP (5–50 mg/L) with chronic diarrhoea
- Family history of IBD with new GI symptoms (mild presentation)
- Chronic diarrhoea >6 weeks with normal or mildly abnormal bloods
- Mild extraintestinal features (arthralgia, aphthous ulcers) with GI symptoms
Action: Standard gastroenterology referral; follow up if no appointment within 8 weeks; interim management in primary care
Writing an Effective Referral
To facilitate timely specialist triage, the referral should include:
- Duration and nature of symptoms (diarrhoea frequency, bleeding, weight loss)
- Nocturnal symptoms (waking from sleep)
- Extraintestinal features (joints, skin, eyes, mouth)
- Perianal symptoms (pain, discharge, skin tags)
- Smoking status (smoking worsens CD; protective in UC)
- Family history of IBD, coeliac disease, or colorectal cancer
- Current medications — especially NSAIDs, antibiotics, and oral contraceptive pill
- Results of FBC, CRP, ESR, faecal calprotectin, stool MCS
- Previous GI investigations (endoscopy reports, imaging)
- Any interim treatment commenced
Acute severe presentation: If the patient presents with signs of acute severe colitis — bloody diarrhoea >6/day, fever, tachycardia >90 bpm, anaemia, ESR >30 mm/hr, or signs of peritonitis — this is a medical emergency. Transfer to the emergency department and contact the gastroenterology registrar on call. Do not delay for outpatient referral.
Perianal disease referral: Patients with suspected perianal Crohn's disease (recurrent perianal abscesses, fistulae, complex fissures, or non-healing perianal wounds) should be referred urgently. They may benefit from examination under anaesthesia (EUA) with MRI pelvis and should not be managed with repeated incision and drainage alone, as the underlying fistulising disease requires specialist medical and surgical co-management.
Interim Symptom Management
While awaiting specialist review, primary care plays an essential role in supporting the patient, managing symptoms, correcting nutritional deficiencies, and preventing harm. The following measures are appropriate interim strategies that do not compromise subsequent specialist assessment.
1. Hydration & Fluid Management
Patients with chronic diarrhoea are at risk of dehydration and electrolyte disturbance, particularly the elderly and those with comorbidities.
- Encourage oral fluid intake of at least 2–2.5 L/day; water and oral rehydration solutions (ORS) are preferred.
- Commercial ORS solutions (Gastrolyte®, Hydrolyte®) are useful for patients with significant diarrhoea (>4 loose stools/day). Available OTC at Australian pharmacies.
- Avoid high-sugar carbonated beverages and excessive caffeine, which may worsen osmotic diarrhoea.
- Monitor for signs of dehydration: postural hypotension, reduced urine output, dry mucous membranes, confusion (elderly).
- Patients unable to maintain oral hydration or with signs of moderate–severe dehydration should be assessed for IV fluid resuscitation in an acute care setting.
2. Nutritional Optimisation
Malnutrition is common at IBD diagnosis (prevalence 20–50% depending on disease extent) and is associated with poorer outcomes, increased surgical complications, and reduced quality of life.
- Refer to an accredited practising dietitian (APD) early — ideally at the time of referral. MBS items 10950–10970 are available for patients with chronic disease management (CDM) plans (GP Management Plan, Item 721).
- Assess dietary intake with a brief food diary or validated screening tool (MUST — Malnutrition Universal Screening Tool, or the Malnutrition Screening Tool [MST]).
- Patients with significant weight loss or BMI <18.5 kg/m² should be flagged as nutritionally at risk.
- No specific dietary intervention has been proven to induce remission in IBD, but general recommendations include adequate protein intake (1.0–1.5 g/kg/day), micronutrient-rich foods, and avoidance of known dietary triggers during flares.
- Exclusive enteral nutrition (EEN) is a first-line induction therapy for paediatric CD and may be discussed with the specialist, but initiation is generally deferred to the gastroenterology team.
3. Medication Review — Avoid Harmful Agents
Avoid NSAIDs in suspected IBD. Non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, diclofenac, aspirin at analgesic doses) are associated with disease flares, GI ulceration, and IBD-related hospitalisation in both CD and UC. Use paracetamol as the preferred analgesic. If additional pain relief is needed, consult the gastroenterologist before initiating therapy.
Antibiotic caution: Do not prescribe empirical antibiotics for suspected IBD. Antibiotics may be indicated if concurrent GI infection is identified (e.g., C. difficile colitis), but unnecessary antibiotic use may disrupt gut microbiota and worsen IBD symptoms. If C. difficile is confirmed, oral vancomycin 125 mg QID for 10 days is first-line per Australian guidelines.
4. Iron Supplementation for Anaemia
Iron-deficiency anaemia affects 30–60% of IBD patients and contributes significantly to fatigue and reduced quality of life. Correction should be initiated in primary care where possible.
Ferrous Sulphate
Ferro-Gradumet® · Generic · Oral iron (first-line)
Adult dose
325 mg (105 mg elemental iron) PO once daily or on alternate days
Frequency
Alternate-day dosing is preferred (improved fractional absorption, reduced GI side effects)
Duration
Continue until ferritin >100 µg/L and Hb normalised (typically 3–6 months); reassess at 4–6 weeks
Key notes
May worsen GI symptoms (nausea, cramping, constipation); often poorly tolerated in active IBD. If oral iron not tolerated or Hb <90 g/L, consider IV iron
PBS status
✔ PBS General Benefit
Ferric Carboxymaltose (IV Iron)
Ferinject® · IV iron infusion
Adult dose
Up to 1000 mg IV infusion over 15 minutes (single session); may repeat after 1 week if total iron deficit exceeds 1000 mg
Indications
Oral iron intolerance, Hb <90 g/L, ongoing blood loss, or failed oral iron trial (>4 weeks with no response)
Setting
Day infusion centre, hospital outpatient, or GP practice with resuscitation facilities; observe for 30 min post-infusion
Key notes
Risk of hypophosphataemia; check phosphate at 1–2 weeks if symptomatic. Anaphylaxis risk is very low (~1:200 000) but infusion must occur in a monitored setting
PBS status
⚕ PBS Authority Required
Loperamide
Imodium® · Generic · Antimotility agent
Adult dose
2 mg PO after each loose stool; maximum 16 mg/day
Indication
Symptomatic relief of diarrhoea only after infection excluded and only in mild–moderate suspected IBD (not acute severe colitis)
Key notes
Contraindicated in acute severe colitis (risk of toxic megacolon). Do not use if C. difficile or invasive bacterial infection suspected. Short-term use only pending specialist review
PBS status
✔ PBS General Benefit
5. Symptom Monitoring & Safety Netting
Establish a clear safety-netting plan while the patient awaits specialist review:
- Advise the patient to return immediately if: bleeding worsens, new fever develops, pain becomes severe or constant, or they feel systemically unwell.
- Schedule a follow-up appointment at 2–4 weeks to review symptoms, check investigation results, and confirm referral status.
- Recheck FBC and CRP at 4–6 weeks if initially abnormal — assess for trajectory.
- If the patient has not been seen by the specialist within 8 weeks (routine referral), follow up and escalate the referral.
- Document the safety-netting advice and follow-up plan in the patient's record.
6. Psychosocial Support
A new diagnosis of suspected IBD can generate significant anxiety. Primary care should acknowledge the patient's concerns and provide support:
- Refer to Crohn's & Colitis Australia (crohnsandcolitis.com.au) for patient education resources, support groups, and a nurse helpline.
- Consider a mental health treatment plan (MBS item 721/723) if the patient reports significant anxiety or depression symptoms.
- Engage a GP Management Plan (Item 721) and Team Care Arrangement (Item 723) early to facilitate coordinated chronic disease management and access allied health services.
Special Populations
Pregnancy
Key considerations
Active IBD during pregnancy increases the risk of preterm birth, low birth weight, and miscarriage. Paradoxically, untreated disease poses greater fetal risk than appropriate treatment. Women of childbearing age with suspected IBD should be referred urgently to allow diagnosis and stabilisation before conception where possible.
Investigations
Faecal calprotectin and blood tests are safe in pregnancy. Avoid MRI with gadolinium (first trimester); non-contrast MRI is acceptable. Colonoscopy is generally deferred unless clinically urgent.
Medications
Mesalazine (5-ASA) is considered safe in pregnancy (Category A). Avoid methotrexate (Category X — teratogenic). Corticosteroids may be used if needed. Thiopurines (azathioprine) are generally continued. Seek specialist guidance early.
Paediatrics
Key considerations
Paediatric IBD (particularly very early-onset <6 years) may present atypically with isolated growth failure, delayed puberty, or isolated iron-deficiency anaemia without prominent GI symptoms. Monogenic causes should be considered in very young children.
Faecal calprotectin
Normal values are higher in children <4 years (up to ~200 µg/g may be physiological). Values ≥250 µg/g in children >4 years are highly suspicious. Interpret with age-specific reference ranges.
Referral
All paediatric patients with suspected IBD should be referred to a paediatric gastroenterologist (available at children's hospitals in all Australian capital cities). Referral should be urgent if any red-flag features present. Endoscopy under general anaesthesia is standard in paediatrics.
Growth monitoring
Plot height and weight on WHO/CDC growth charts. Declining growth velocity may be the earliest sign of IBD in children. Calculate BMI z-score. Refer if growth faltering is unexplained.
Elderly (≥65 years)
Key considerations
IBD diagnosed in the elderly (≥60 years at onset) accounts for 10–15% of new cases. UC is more common than CD in this age group. Colorectal cancer and diverticular disease are important differentials that may coexist with IBD.
Polypharmacy risk
Review all medications for GI-harming agents (NSAIDs, low-dose aspirin, anticoagulants, bisphosphonates, SSRIs). Increased infection risk with immunosuppression. Ensure Pneumococcal, influenza, and herpes zoster vaccination before initiating immunosuppressants.
Dehydration risk
Elderly patients with diarrhoea are at high risk of acute kidney injury and electrolyte derangement. Lower threshold for checking renal function (U&E) and for IV fluid resuscitation if required.
Renal Impairment
Key considerations
Patients with CKD and chronic diarrhoea may develop significant electrolyte derangement (hypokalaemia, hypomagnesaemia, hyponatraemia). Mesalazine (5-ASA) rarely causes interstitial nephritis — baseline renal function must be established. Iron supplementation may require IV formulation if oral not tolerated.
Investigations
Check U&E, eGFR, magnesium, and phosphate at baseline and at follow-up. Urinalysis for proteinuria (nephrotoxicity screening). Adjust any prescribed medications for renal function.
Immunocompromised
Key considerations
Patients on immunosuppressive therapy (transplant recipients, biologics, corticosteroids) with chronic diarrhoea must be evaluated for opportunistic infections (CMV colitis, C. difficile, Mycobacterium avium complex, cryptosporidiosis) before attributing symptoms to IBD flare.
CMV colitis
Consider CMV colitis in immunocompromised patients with bloody diarrhoea and systemic symptoms. Request CMV PCR on stool or blood. Tissue diagnosis via colonoscopy biopsy is gold standard. CMV may also complicate established IBD, particularly in those on corticosteroids or thiopurines.
Vaccination status
Ensure hepatitis B serology, varicella status, HIV testing, and TB screening (IGRA) are checked before immunosuppressant initiation, as these tests form part of the pre-biologic workup.
Hepatic Impairment
Key considerations
Primary sclerosing cholangitis (PSC) coexists with UC in 3–5% of patients. Elevated ALP/GGT in a patient with suspected IBD should prompt MRCP and specialist hepatology referral. LFTs should be checked at baseline and monitored.
Medications
Hepatic impairment may affect clearance of corticosteroids, azathioprine (risk of hepatotoxicity), and methotrexate (contraindicated in significant liver disease). LFTs required at baseline before any hepatotoxic agent.
Aboriginal and Torres Strait Islander Health Considerations
Aboriginal and Torres Strait Islander Health
IBD in Aboriginal and Torres Strait Islander Australians remains under-researched but is increasingly recognised as a significant health concern. Available data suggest that Indigenous Australians may present later, have more complicated disease at diagnosis, and experience greater barriers to accessing specialist gastroenterology services. Culturally safe, trauma-informed care is essential at every stage of the patient journey.
Key principle: Chronic diarrhoea in Aboriginal and Torres Strait Islander Australians should not be automatically attributed to infectious causes without investigating for IBD, especially when symptoms persist beyond 4–6 weeks despite appropriate antimicrobial treatment, or when red-flag features (weight loss, bleeding, anaemia, nocturnal symptoms) are present.
📚 References
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