Ankylosing spondylitis and a diagnostic dilemma: coccydynia.

ABSTRACT

OBJECTIVES: Coccydynia is defined as pain in or around the tail bone area. The most common cause of coccydynia is either a trauma such as a fall directly on to the coccyx or repetitive minor trauma. The etiology remains obscure in up to 30% of patients. The literature on the contribution of rheumatic diseases to coccydynia is scarce. Our objective was to investigate the prevalence of coccydynia in ankylosing spondylitis (AS) patients. METHODS: One hundred and seven consecutive patients with AS were evaluated for coccydynia were enrolled between January and November 2012 for a cross-sectional analysis. Seventy-four consecutive patients were followed for mechanical back pain as controls and the AS patients were interviewed for the presence of coccydynia. The data collected was evaluated on SPSS® version 11.5 and Microsoft Excel® Programmes. RESULTS: Prevalence of coccydynia in AS (38.3%) was significantly higher than the control group (p<0.0001) in both female and male AS patients (female AS vs. control=40.9% vs. 18.4%, p=0.015 and male AS vs. control=36.5% vs. 8.0%, p=0.005). Both genders were affected equally in the AS group whereas coccydynia was slightly more frequent in female patients in the control group. CONCLUSIONS: Coccydynia is a previously neglected symptom of AS and it is almost three times more common in AS than in non-specific chronic low back pain. Our observation may implicate that inflammatory diseases have a role in the etiology of coccydynia, especially in those without a history of recent or past trauma and coccydynia may be a factor associated with the severity of AS as well.