PA23.5-7 | Intestinal TB, Appendicitis, IBD & Malabsorption — Summary & Reflection

REFLECT

You have now covered four conditions that collectively underpin a large part of GI medicine and surgery in India. Take a few minutes to reflect:

1. A patient with ileocaecal disease and granulomas on biopsy — list the three steps you would take to confidently distinguish intestinal TB from Crohn disease before prescribing.

1. In a child with right iliac fossa pain, what is the earliest definitive histological change you would look for on the appendix specimen?

1. You have a patient with chronic diarrhoea and weight loss. Construct a two-step laboratory algorithm that first localises the defect and then identifies the most likely cause in an Indian patient.

Compare your answers with the content of this module. Discuss the TB vs Crohn distinction with a clinical colleague — this is a decision you will face in practice.

KEY TAKEAWAYS

Intestinal tuberculosis preferentially affects the ileocaecal region. Ulcerative form: transverse girdle ulcers with caseating granulomas in all layers. Hyperplastic form: fibrotic mass/stricture. Distinguished from Crohn by caseating granulomas, transverse ulcers, positive AFB/IGRA, and absence of fistulae.

Acute appendicitis follows a cascade: luminal obstruction → pressure → ischaemia → bacterial invasion → transmural inflammation. Stages: acute → suppurative → gangrenous → perforation. Diagnostic histology: neutrophils in muscularis propria. Complications include peritonitis, abscess, portal pyaemia.

Crohn disease vs ulcerative colitis: Crohn is transmural, skip lesions, any GI segment, non-caseating granulomas, fistulae, cobblestone mucosa. UC is mucosal, continuous from rectum, crypt abscesses, pseudopolyps, lead-pipe colon. UC has higher colorectal cancer risk; Crohn is not cured by surgery. PSC is strongly associated with UC.

Malabsorption syndrome: confirm with faecal fat; localise with D-xylose (low = mucosal, normal = luminal/pancreatic); identify cause with anti-tTG/biopsy (coeliac), tetracycline response (tropical sprue), Schilling test (B12 pathway), hydrogen breath test (lactase/SIBO). Coeliac biopsy hallmarks: villous atrophy, crypt hyperplasia, increased intraepithelial lymphocytes.