Histopathologic evidence that sacroiliitis in ankylosing spondylitis is not merely enthesitis.

OBJECTIVE: To systematically study the histopathology of sacroiliitis in ankylosing spondylitis (AS) at 5 different stages of the disease. METHODS: Two independent observers assessed 75 microscopic features in the sacroiliac (SI) joints in 12 cases of AS (5 biopsies, 7 autopsies) and in 22 control cases (all autopsies). RESULTS: In AS, synovitis, pannus formation, myxoid marrow, superficial cartilage destruction, enthesitis, intraarticular fibrous strands, new bone formation, and bony ankylosis were significantly more frequent than in control cases, in which there was more endochondral bone within deep-zone articular cartilage. Cartilaginous fusion occurred in both groups, but much earlier in AS. There was no residual synovium when the joint lumen was totally occluded. Mild but destructive synovitis and myxoid subchondral bone marrow were the earliest changes identified in AS. These lesions destroyed the adjacent articular tissues, a loss that was followed to varying degrees by fibrous scarring, woven bone, and new cartilage. The original cartilages also fused, and chondral fusion was the predominant mode of ankylosis. Both the original and the reparative cartilaginous tissues were replaced by bone. Active enthesitis occurred in 2 advanced and 3 late cases; fibrous scar tissue, presumed to represent previous enthesitis, was observed in all stages except the earliest. Paraarticular bone was at first dense, and later porotic. CONCLUSION: In the sacroiliitis of AS, two findings predominate: 1) synovitis and subchondral bone marrow changes offer a more rational explanation for widespread joint destruction than does enthesitis; and 2) an unusual form of chondroid metaplasia contributes to ankylosis.

Commented glossary for rheumatic spinal diseases, based on pathology.

OBJECTIVES: To redefine and comment on terms on a pathological basis, in order to avoid the confusion due to the use of terms with different meanings, to standardise usage among clinicians, radiologists and pathologists, and to facilitate literature searches. METHODS: Within the Committee of Pathology of the European League against Rheumatism, a study group was set up to analyse the medical literature and common practice concerning the nomenclature of rheumatic spinal diseases. The group tried to amalgamate the main trends in the field, to reconcile etymology, historical background, morphology, and common practice. RESULTS: The group warns against use of the terms 'acquired hyperostosis syndrome', '(von) Bechterew's disease', 'Kümmel's disease', 'pseudospondylolisthesis', 'rheumatoid spondylitis', 'spondylarthropathy' in the sense of spondarthritis, and 'spondylosis'. It recommends intercorporal or interapophyseal rather than intervertebral (osteo) chondrosis, zygapophyseal diverticulum rather than cyst, disc hernia rather than prolapse, spondyloarthritis rather than spondyloarthropathy, marginal rather than anterior spondylitis, and discarthrosis. It proposes 'zygarthrosis' to designate zygapophyseal osteoarthrosis. CONCLUSIONS: Knowledge of the pathological basis of diseases and an understanding of the original definitions given by those who coined new terms make it possible to avoid most of the confusion arising from improper use of spinal terms.

Historical aspects of the aetiology of rheumatoid arthritis.

Since the first description of the disease in the early part of the nineteenth century, the aetiology of rheumatoid arthritis has been associated with the interacting concepts of diathesis or internal factors and environment or external factors.

Monarticular rheumatoid-like arthritis of seven years' duration following fracture of the radial head.

We report a patient who developed rheumatoid-like arthritis in an elbow joint following a fracture. The arthritis has remained localised to that joint for seven years.

Illustrated glossary for spinal anatomy. With explanations and a French and German translation.

The authors define, explain, and illustrate a number of concepts pertaining to normal spinal anatomy that are of practical use but omitted in standard anatomical sources or are the subject of conflicting views: bony and cartilaginous end-plate, marginal ring, cortex of the vertebral body, isthmus, neurocentral junction, uncus, uncovertebral joint, zygapophyseal joint, annulus fibrosus, shorter and longer perivertebral ligaments, interspinous bursa, mamillo-accessory ligament. A French and German translation of recommended terms is provided as well.

Historical perspectives in the aetiology of ankylosing spondylitis.

A brief historical review of the aetiology of ankylosing spondylitis is presented. A recurrent theme has been diathesis and infection. Diathesis has now been pinpointed to the 6th chromosome in the form of HLA-B27, but, as yet, we know little of any infective aetiology for ankylosing spondylitis itself.

Rheumatoid and other diseases of the cervical interspinous bursae, and changes in the spinous processes.

Bursal spaces between the cervical interspinous processes were found at necropsy in 14 out of 27 "normal' adult necks, especially when the spines were close together. In this random series they were the seat of crystallopathic disease in 2 instances out of 14 cases. In spines from 9 cases of adult-onset rheumatoid arthritis, rheumatoid bursitis was seen in 2 and banal bursitis in 2. In juvenile-onset chronic arthritis inflammatory bursal changes of rheumatoid nature were found in 2 out of 5 cases, and are compared with the "normal'. A third case showed crystallopathic destruction. In one instance of adult RA very severe changes were seen, with destruction of the spinous processes, and this was associated with hypermobile segments dependent on discal destruction starting in the oncovertebral joints. An association is described between discal lesions, spinous erosion, enthesopathy, and interspinous bursitis.

Adult-onset Still's disease. Twenty-year followup and further studies of patients with active disease.

Eleven female patients with adult-onset Still's disease were followed for 7-36 years (mean 20.2 years) after the onset of their illness. Ten of these patients had a chronic course characterized by remissions and exacerbations of arthritis associated with fever and rash. Five patients had terminal interphalangeal involvement, and carpal ankylosis was demonstrated on x-ray film in 10. Two patients developed a widespread polyarthritis, and renal amyloidosis was diagnosed 10 years after disease onset in the most severely affected patient. In 4 patients studied during an exacerbation of the disease, circulating immune complexes were detected by the staphylococcal A binding assay, but not by the C1q binding assay. Synovial fluid analysis in 1 patient revealed a low C3 level and total hemolytic complement (CH50) together with immune complexes and IgG rheumatoid factor. Immune complexes were not identified in the characteristic Still's rash by immunofluorescence or electron microscopy, although mast cell degranulation, neutrophil lysis, and perivascular fibrin deposition were reminiscent of immune complex--mediated vascular injury. The clinical and laboratory features as well as the long-term course of adult- and juvenile-onset systemic Still's disease are similar, but further studies of genetic markers and immunopathology are required to establish a common pathophysiology.

The lumbar interspinous bursae and Baastrup's syndrome. An autopsy study.

This study describes the prevalence, distribution, pathology and pathogenesis of lumbar interspinous bursitis (described as a clinical syndrome by Baastrup in 1933). It is based on an anatomic study of 152 lumbar spines derived from routine and random postmortem material, together with selected specimens from autopsies on patients with various rheumatic diseases. From a statistical study of 50 randomly chosen spines, bursae are found when the interspinous distance is small compared with the total height of the lumbar spine ('bursal index'): nearly all bursal spaces show some sign of inflammation and a few show severe bony erosion. Crystal deposits therein are also described.

Observations on chronic polyarthritis in monkeys.

Erosion and inflammatory changes in the carpus, fingers and toes of a rhesus monkey, Macaca mulatta, are described; this was one of 152 animals in each of which four fixed limbs were available for examination. The histological changes resembled closely those found in adult human rheumatoid arthritis. The limited literature is reviewed (including cases with amyloid disease).

Thoracic intervertebral discitis in rheumatoid arthritis due to costovertebral joint involvement.

Discitis (with intervertebral disc destruction), found pathologically in the thoracic region of 8 out of 114 rheumatoid patients, is shown to derive and spread from primary rheumatoid involvement of the costovertebral joints. Erosion and destruction of bone may occur, followed by healing, visible radiologically as disc narrowing and posterolateral bony sclerosis and sometimes with ankylosis. There are few clinical symptoms, since most of these patients have limited locomotor function.