Past exam of the medicine course of the University of Oxford / 1866 / Second examination / Pathology / 4

Describe the structure of the lesions of the bowels in continued fever and phthisis.

The classical contrast is between ulceration centred on intestinal lymphoid tissue in enteric fever and granulomatous, often circumferential ulceration in intestinal tuberculosis. The historical expression continued fever covered more than one illness. The characteristic bowel lesions meant here point especially to typhoid fever; they should not be attributed indiscriminately to typhus or every prolonged fever.

In typhoid fever, Peyer's patches and solitary lymphoid follicles, particularly in the terminal ileum, enlarge and become infiltrated. Their breakdown and necrosis lead to sloughing and ulceration. The larger ulcers characteristically follow the long axis of the intestine, reflecting the shape of the affected aggregated lymphoid patch on the side opposite the mesentery. Depending on their stage, one may see swollen patches, necrotic sloughs, open ulcers or healing surfaces. Depth varies; erosion into a blood vessel can cause haemorrhage, while full-thickness destruction can cause intestinal perforation and peritonitis.

Microscopically, the important cellular component includes swollen macrophages with ingested organisms and cellular debris; this is not simply a dense collection of neutrophils forming an ordinary abscess. The surrounding mucosal architecture may become severely disturbed. These current cellular descriptions refine the gross lesion recognized before the causative organism was identified.^[ref][ref]

In historical phthisis, bowel disease frequently meant intestinal tuberculosis associated with pulmonary tuberculosis. Lesions commonly involve the terminal ileum and ileocaecal region, although other sites occur. Nodules in mucosal or submucosal lymphoid tissue undergo caseous necrosis, coalesce and break through the mucosa. The ulcerated surface tends to spread transversely and may encircle the bowel. The edges can be irregular and undermined, with additional tuberculous granulomas in the wall, serosal surface or draining lymph nodes. Progressive fibrosis may narrow the lumen and produce a stricture; thickened masses as well as ulcers can occur.^[ref]

A section from a tuberculous ulcer may show central caseous necrosis bordered by epithelioid macrophages, giant cells and lymphocytes. A section from an enteric-fever ulcer instead emphasizes destruction of lymphoid patches with macrophage-rich infiltration. A practical anatomical examination records site, orientation, depth, edges, intervening mucosa, serosal nodules and draining lymph nodes, rather than judging one detached fragment in isolation.

Longitudinal lymphoid-patch ulcers favour the classical enteric-fever pattern; transverse, caseating and often stenosing lesions favour intestinal tuberculosis. These are useful patterns rather than absolute rules. Modern microbiological culture, organism-specific molecular tests and appropriately sampled histology can establish the cause when gross appearances overlap.