Psoas abscess without spinal disease: the value of lymphangiography in tuberculous lymphadenitis.

THE ASSOCIATION of psoas abscess with tuberculosis of the spine or sacroiliac joints is well recognized and occurs in about a fifth of such cases (Mercer & Duthie, 1964). It has long been known that psoas abscess may also occur without evidence of spinal disease, when it is often not of tuberculous origin. Mynter (1881) described cases of 'acute psoitis', and of the seven psoas abscesses without spinal disease reported by Rogers (1911), only two were tuberculous. The non-tuberculous psoas abscess often appears to be of primary haematogenous origin (Zadek, 1950; Lam & Hodgson, 1966), and is particularly liable to occur in children (Mynter, 1881; Lam & Hodgson, 1966), in whom it may present as an 'irritable hip'. Of the various organisms responsible the commonest is the staphylococcus, and where antibiotics have been given the pus might be sterile (Lam & Hodgson, 1966). Occasionally secondary infection occurs in a haematoma due to trauma (Binns, 1966) or haemophilia (Tordoir, 1951). Another mode of infection, both pyogenic and tuberculous, is by direct spread from adjacent structures. The psoas sheath is not a continuous sheet of tissue as suggested by Mynter (1881), but has defects where vessels and nerves penetrate. Perinephric infection can enter it via the defect inferiorly in the perinephric fascial layers (Aird, 1957). Appendix abscess, diverticulitis coli, intestinal perforations and even pleural infection were sometimes implicated (Tordoir, 1951). Rogers (1911) postulated that suppurating or caseating lymph nodes in contact with the sheath could lead to psoas abscess, and anatomical considerations suggest that this could occur with posterior mediastinal as well as with retro-peritoneal nodes. Thus psoas abscess presenting without a spinal lesion may require careful investigation in order to diagnose completely the underlying disease. Two cases of tuberculous psoas abscess without spinal disease are reported below.