Page 849 - Textbook of Pathology, 6th Edition

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Figure 28.4 Osteomyelitis of the vertebral body.

COMPLICATIONS. Osteomyelitis may result in the from infection elsewhere, usually from the lungs, and
following complications: infrequently by direct extension from the pulmonary or
1. Septicaemia. gastrointestinal tuberculosis (page 156). The disease affects
2. Acute bacterial arthritis. adolescents and young adults more often. Most frequently
3. Pathologic fractures. involved are the spine and bones of extremities.
4. Development of squamous cell carcinoma in long-
standing cases. MORPHOLOGIC FEATURES. The bone lesions in tuber-
5. Secondary amyloidosis in long-standing cases. culosis have the same general histological appearance as
6. Vertebral osteomyelitis may cause vertebral collapse with in tuberculosis elsewhere and consist of central caseation CHAPTER 28
paravertebral abscess, epidural abscess, cord compression necrosis surrounded by tuberculous granulation tissue
and neurologic deficits. and fragments of necrotic bone (Fig. 28.5). The tuberculous
lesions appear as a focus of bone destruction and replace-
Tuberculous Osteomyelitis ment of the affected tissue by caseous material and
formation of multiple discharging sinuses through the soft
Tuberculous osteomyelitis, though rare in developed tissues and skin. Involvement of joint spaces and
countries, continues to be a common condition in under- intervertebral disc are frequent. Tuberculosis of the spine,
developed and developing countries of the world. The Pott’s disease, often commences in the vertebral body and
tubercle bacilli, M. tuberculosis, reach the bone marrow and may be associated with compression fractures and
synovium most commonly by haematogenous dissemination
destruction of intervertebral discs, producing permanent
damage and paraplegia. Extension of caseous material
along with pus from the lumbar vertebrae to the sheaths The Musculoskeletal System
of psoas muscle produces psoas abscess or lumbar cold
abscess (Fig. 28.4,B). The cold abscess may burst through
the skin and form sinus. Long-standing cases may develop
systemic amyloidosis.

AVASCULAR NECROSIS (OSTEONECROSIS)
Avascular necrosis of the bones or osteonecrosis results from
ischaemia. It is a relatively common condition.

ETIOPATHOGENESIS. It may occur from following
causes:
1. Fracture or dislocation
2. Sickle cell disease
3. Corticosteroid administration
4. Radiation therapy
5. Chronic alcoholism
6. Idiopathic
The pathogenetic mechanism of osteonecrosis in many
cases remains obscure, while in others it is by interruption
Figure 28.5 Tuberculous osteomyelitis. There are epithelioid cell in the blood supply to the bones induced by direct trauma,
granulomas with minute areas of caseation necrosis and surrounded by
Langhans’ giant cells. Pieces of necrotic bone are also seen. compression, or thromboembolic obstruction.