A deceptive presentation of Tuberculosis hip as Staphylococcal infection, its successful management and literature review

Correspondence to Chetan Muralidhara Rao Dojode, [email protected]

Background 

Tuberculosis (TB) arthritis constitutes approximately 1–3% of all TB cases and 10–11% of extrapulmonary cases.¹ The skeletal TB accounts for 2.2–4.7% of all TB cases in Europe and USA.² Skeletal TB shows bimodal age distribution; in developed countries it affects older, whereas in immigrants and endemic areas it affects younger individuals.² TB mainly involves the large weight-bearing joints particularly hips, knees and ankles.¹

TB as a concomitant infection with Staphylococcus is rare and has been reported in the knee and the ankle.^{3 4} Diagnosis of joint TB is often delayed due to lack of awareness, insidious onset, lack of characteristic early radiographic findings and often lack of constitutional or pulmonary involvement.¹

Case presentation

A 71-year-old patient who is a retired farmer was referred by the general practitioner for arthritis of the hip. He had no history of contact with TB and the farm animals where he had worked 12 years ago were tested regularly.

While awaiting an orthopaedic outpatient review, he was admitted under the medical team for confusion and sepsis associated with raised inflammatory markers; C reactive protein (CRP) of 210. Plain radiographs showed hip with features consistent with septic arthritis (figure 1).⁵ An MRI scan also showed effusion of the hip and extension into the psoas and the pattern of bone destruction was better delineated on a CT scan (figures 2–4).

As there was no other focus of infection identified and the blood culture was negative, an aspiration of the hip was done on the basis of a clinical diagnosis of septic arthritis. The culture grew methicillin-sensitive Staphylococcus aureus and the patient was started on high dose of intravenous flucloxacillin therapy.

Radiologically, there was destruction of femur head contained in enlarged acetabulum raising suspicion of a pestle and mortar appearance of TB hip. Patient was not improving with intravenous antibiotic therapy, so later he underwent debridement and excision of the femoral head and insertion of a antibiotic impregnated cement spacer (figure 5). The cement spacer was loaded with 1 g of gentamycin per 40 mg of cement. There was some caseous necrosis of the femoral head so the specimen was sent for acid fast bacilli (AFB) staining and...