Cauda Equina Syndrome in Ankylosing Spondylitis: Challenges in Diagnosis, Management, and Pathogenesis.

OBJECTIVE: Cauda equina syndrome (CES) is a rare neurologic complication of longstanding ankylosing spondylitis (AS). It is unclear what causes CES, and no proven or effective therapy has been reported to date. We have encountered 6 patients with longstanding AS diagnosed with CES. We set about to study their features, review the literature, and generate hypotheses regarding pathophysiology, as well as to speculate on the possibilities of early recognition and prevention. METHODS: We obtained permission from 6 patients with longstanding AS and CES to access their medical records and imaging studies for research purposes related to this paper. We collected and reviewed each patient's medical history, imaging studies, disease duration, past therapies especially those that relate to AS, laboratory data, as well as any treatment they received for CES and followup results of each case to the present time. RESULTS: The 6 cases of CES with AS have remarkable similarity to each other in that several decades of the disease had passed before neurologic symptoms and later signs appeared. All cases have fused spines and facet joints without spinal fractures, spinal stenosis, or disc herniation. CONCLUSION: CES is a rare yet debilitating neurologic complication of longstanding AS. The pathophysiology and treatments are far from clear. We postulate that chronic enthesitis of the vertebral column initiates the process that results in dural stiffening and formation of ectasias, causing downstream nerve root damage.

Visual assessment of the spine bruckel instrument, a novel status tool to reflect appearance of the spine in patients with ankylosing spondylitis.

OBJECTIVE: The Visual Assessment of the Spine Bruckel Instrument (VASBI) is a new status tool developed by the Spondylitis Association of America and the University of Toronto to reflect spinal appearance in patients with ankylosing spondylitis (AS). Our objective was to validate the VASBI according to the Outcome Measures in Rheumatoid Arthritis Clinical Trials filter (truth, discrimination, and feasibility). METHODS: Three hundred patients with AS were asked to rate their degree of perceived spinal deformity using the VASBI. To evaluate construct validity, VASBI scores were compared with functional outcome, spinal mobility, and radiographic spinal damage. Test-retest reliability was evaluated using kappa statistic (kappa). RESULTS: Patient VASBI demonstrated strong correlation with spinal mobility (r = 0.543) and moderate correlation with functional impairment (r = 0.490) and structural damage (r = 0.309). Reliability for VASBI was very good (kappa = 0.973, p < 0.001). CONCLUSION: The VASBI is a novel tool with practical applications in a busy clinical setting as it simplifies assessment of AS spinal deformity. Our study demonstrates that the VASBI has good feasibility, construct validity, and reliability.

Juvenile-onset ankylosing spondylitis is associated with worse functional outcomes than adult-onset ankylosing spondylitis.

OBJECTIVE: To compare functional outcome of patients with juvenile-onset ankylosing spondylitis (JoAS; defined as AS with symptom onset before 16 years of age) with that of patients with adult-onset AS (AoAS) and to identify variables associated with a poor functional outcome of JoAS. METHODS: A cross-sectional study was performed of 326 JoAS patients who participated in a postal survey conducted by the Spondylitis Association of America. This cohort was compared with 2,021 AoAS patients who participated in the same survey. Simple and multiple logistic regression analyses were performed to identify differences with respect to clinical features, demographic features, and functional outcome (defined by the Bath Ankylosing Spondylitis Functional Index [BASFI]) between the 2 groups. A validation cohort of 255 AS patients was also surveyed. RESULTS: The mean +/- SD BASFI score (controlled for disease duration) for JoAS was 51.3 +/- 1.5 compared with 46.4 +/- 0.6 for AoAS (P < 0.0001). Multiple logistic regression identified only age (P < 0.0001) and income status (P < 0.0001) as factors associated with functional impairment. CONCLUSION: It appears that JoAS is a progressive disease and is associated with significant delay in diagnosis and worse functional outcome compared with AoAS. Furthermore, women do worse than men with JoAS. This would argue for the importance of early diagnosis and treatment of AS, particularly in the subgroup of patients with JoAS.

Genetic studies in familial ankylosing spondylitis susceptibility.

OBJECTIVE: To define the genetic basis of susceptibility to ankylosing spondylitis (AS), especially non-major histocompatibility complex (MHC) genes. METHODS: The study group comprised 244 affected sibling pairs from 180 pedigrees of primarily European ancestry. Sibling pairs were concordant for AS by the modified New York criteria and had available sacroiliac radiographs. The subjects were genotyped for 400 markers in ABI PRISM linkage map MD-10 and for 17 additional markers on chromosomes 6p, 6q, and 11q (including HLA-B, DRB1, DQA1, DQB1, and DPB1 alleles). Two-point and multipoint nonparametric linkage (NPL) analyses were conducted using the NPL statistic and 1-parameter allele-sharing model logarithm of odds (LOD) scores, calculated using the Allele-Sharing Model (ASM) computer program. RESULTS: Linkage of the MHC region was supported by both 2-point and multipoint analyses, with the strongest peak (45.90 cM) in the MHC at the HLA-DRB1 locus (NPL score 8.720, ASM LOD score 20.49; P = 6.8 x 10(-20) for 2-point analysis). A second region was found to have positive linkage at the q arm of chromosome 6 (D6S441) in 2-point analysis; this was supported by a 39.13-cM region (135.58-174.71 cM) in multipoint analysis, with the smallest P value (4.2 x 10(-3)) at 166.39 cM. A third region was found on chromosome 11q, with the strongest evidence for linkage for D11S4094 at 123 cM (NPL score 2.235, ASM LOD score 1.939) and, on transmission disequilibrium test analysis, D11S4090 at 105.74 cM (P = 6.2 x 10(-5)). Linkage in this area was supported by multipoint analysis, spanning 22.19 cM continuously from 101.68 cM to 123.87 cM, with the strongest peak at 112.33 cM (P = 0.014); this was confirmed by subsequent fine mapping studies. CONCLUSION: Thus, this genome-wide scan implicates, in addition to the MHC, regions outside the MHC in AS susceptibility, especially on chromosomes 6q and 11q.

Spondylitis association of America: the member-directed, nonprofit health organization addressing the needs of ankylosing spondylitis patients.

Ankylosing spondylitis (AS) involves a spinal arthritis that affects young adults, with an onset usually between 17 and 35 years of age. Although historically underdiagnosed, AS strikes at least 1 million Americans. Enhancing the quality of lives of AS patients in the United States is one of the goals of the Spondylitis Association of America (SAA). To this end, the SAA strives to expand the knowledge and resources available for AS patients and for health professionals. This article explores how the SAA addresses the needs of patients living with spondylitis. This article explains that through its effective collaborations, the SAA dedicates itself to the eradication of AS and related diseases through education, advocacy, awareness, and research.