What additional work up should be considered for a pediatric GI consult?

This is a broad question, as the workup varies considerably depending on the presenting complaint. Here's a structured overview of the investigations commonly considered before or alongside a paediatric GI referral, organised by clinical presentation.

Baseline Investigations (Applicable to Most Referrals)

Bloods

• FBC with differential: looking for anaemia, thrombocytosis, leucocytosis
• Inflammatory markers: CRP and ESR
• Albumin (hypoalbuminaemia is common in Crohn's disease)
• Iron studies: ferritin, transferrin saturation
• Coeliac serology: tissue transglutaminase (tTG) IgA + total IgA (on a gluten-containing diet)
• LFTs including transaminases and GGT

Stool

• Faecal calprotectin (FC): the most useful non-invasive marker to distinguish organic from functional GI disease; a normal FC substantially reduces the likelihood of IBD
• Stool culture: to exclude Salmonella, Shigella, Yersinia, Campylobacter
• Stool for C. difficile toxin
• Stool microscopy for ova, cysts and parasites (especially Giardia)

Growth Assessment

• Plot weight, height, and BMI on percentile charts
• Weight loss, faltering growth, or declining growth velocity are red flags warranting further investigation and warrant more urgent referral

Physical Examination

• Perianal examination: skin tags (particularly if inflamed, multiple, or in atypical positions), fistulae, or abscess may indicate Crohn's disease
• Abdominal examination: hepatosplenomegaly, masses, tenderness
• Extra-intestinal features: oral ulcers, erythema nodosum, joint involvement, uveitis

Presentation-Specific Workup

Suspected IBD (chronic diarrhoea, bloody stools, abdominal pain, weight loss)

• All baseline bloods and stool tests above
• FC is particularly valuable here
• Endoscopy (ileocolonoscopy + EGD with biopsies) is the gold standard and is typically arranged by the GI specialist
• MRI enterography (MRE) for small bowel assessment: sensitive and specific, avoids radiation; should supersede barium studies where available

Iron Deficiency Anaemia

• FBC, iron studies, ESR/CRP, coeliac screen
• Consider nutritional assessment and dietitian referral if dietary intake is inadequate

Chronic Abdominal Pain (without alarm features)

• Baseline bloods and coeliac serology
• FC to help exclude IBD
• Stool MCS/OCP
• Consider H. pylori testing in appropriate populations
• Note: In functional abdominal pain disorders (Rome IV criteria) without red flags, extensive investigation has low diagnostic yield

Liver Disease

• LFTs (ALT, AST, GGT, bilirubin, albumin)
• INR, ammonia
• Age-based aetiological workup (viral serology, metabolic screen, autoimmune markers)
• Abdominal ultrasound

Pancreatic Disease

• Amylase and lipase
• Abdominal ultrasound is often the initial imaging modality
• CT or MRCP may be required for further characterisation

Red Flags Warranting Urgent or Emergency Referral

• Acute significant GI bleeding / melaena
• Acute liver failure (INR >1.5)
• Acute pancreatitis
• Caustic ingestion
• Oesophageal foreign body / food impaction
• Acute diarrhoea with dehydration