 |
2006 Case #8 |  |
| The following patient was seen on the 36-bed tropical disease unit of the Tropical Medicine Institute. |
 History: 31 yo female patient admitted with an 18 month history of low grade fever, right hip pain and progressive difficulty in walking. No improvement on NSAIDs. Eights year earlier after an accident she had an extensive hip reconstructive procedure which included insertion of prosthetic material. No history of obstetric or gynecologic problems.
Epidemiology: Born in the jungle but living in Lima for most of her life. No history of TB contact, but reports ingestion of unpasteurized cheese. Physical Examination: Afebrile, right inguinal lymphadenopathy. Pain on movement of the right hip with marked functional limitation. Laboratory Examination: Hematocrit 31%, WBC 5360 (56% neutrophils, 28% lymphs, 6% eos), ESR 45 mm/h. Widal negative, Brucella negative. ELISA-HIV negative. LFT normal. Chest x-ray normal. Hip x-rays and an MRI of the right hip are shown in Images A, B, C. A diagnostic procedure was performed.
|
| Diagnosis: Mycobacterium tuberculosis infection of the right hip. |
| Discussion: Needle aspiration of the right hip disclosed purulent material with negative Gram and Ziehl-Neelsen stains. Open drainage of the right hip disclosed 100cc of purulent odorless material. Gram, Ziehl-Nielsen and fungal stains were negative again as were routine bacterial and fungal cultures. Culture for mycobacteria is pending. Biopsy of articular tissue disclosed caseating granulomas with extensive areas of necrosis and fibrosis. No AFB organisms were seen. PPD skin test was 16mm.
The plain films of the hip [Image A] disclose the old fracture with prosthetic material on the left side. The close-up of the right hip [Image B] shows marked narrowing of the superior margin of the hip, erosive lesions on the medial-inferior surface of the femoral head, and marked irregularities on the surface of the acetabulum. Image C is a T2 weighted MRI that shows narrowing of the superior margin of the right hip, and disappearance of the cartilage in the remaining joint space. The medial and inferior part of the joint is widened and occupied by a white material consistent with fluid inside the joint. Irregularities and erosions on the acetabulum are also seen. These images (bone destruction with effusion) and clinical picture are consistent with chronic hip arthritis. In Peru, tuberculosisis is by far the most common diagnosis. Other considerations would be chronic pyogenic arthritis (no granulomas would be expected), brucellosis (negative serology for Brucella in this case and culture is still negative), and fungal arthritis (sporotrichosis and histoplasmosis occur in Peru but are a rare cause of chronic arthritis). Skeletal infection accounts for up to a third of cases of extrapulmonary tuberculosis with spinal tuberculosis (Pott?s disease) being the most common. Tuberculous arthritis occurs mostly in the weight-bearing joints, the hip and the knee, and is usually monoarticular. Most often other manifestations of TB are not present and infection is likely due to hematogenous seeding from a self-contained primary lung infection. Constitutional symptoms are present in the minority and progression of joint destruction and disability is usually indolent. Aspiration of joint fluid is usually unhelpful and synovial biopsy should be performed in suspected tuberculosis though acid-fast organisms are often not seen in tissue. Culture in our case is still pending but given the positive PPD, the caseating granulomas and all other cultures and stains being negative, we have begun the patient on four-drug tuberculosis therapy. Traditionally, because of poor drug penetration into bone, skeletal tuberculosis has been an indication for 12-18 months of therapy but a number of recent studies have suggested that standard-duration therapy may be adequate.
|