Ankylosing Spondylitis Presenting as a Severe Kyphotic Deformity Without Pain: A Case Report and Literature Review

Ankylosing spondylitis (AS) is a chronic inflammatory disease predominantly affecting the axial skeleton and sacroiliac joints. Progressive structural remodeling may lead to syndesmophyte formation, spinal ankylosis, and the characteristic "bamboo spine" appearance. In advanced stages, spinal deformities and functional impairment may occur. We report the case of a 32-year-old male presenting with progressive spinal deformity and cosmetic concern without significant current pain. The deformity had progressively developed since adolescence, beginning at the age of 15, and was initially associated with alternating hip pain. Clinical examination revealed marked cervicothoracic hyperkyphosis, sagittal imbalance, left shoulder elevation, and right pelvic tilt. Spinal mobility assessment demonstrated severe limitation, with a Schober index of 1 cm and thoracic expansion reduced to 4 cm. Imaging studies revealed a bamboo spine appearance with fusion of the posterior vertebral elements, while pelvic radiography demonstrated bilateral sacroiliac ankylosis. Laboratory investigations confirmed HLA-B27 positivity. Pulmonary function tests showed a restrictive ventilatory pattern. Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Bath Ankylosing Spondylitis Functional Index (BASFI) scores indicated clinically significant disease activity and moderate functional impairment, respectively. The patient was enrolled in a multidisciplinary management program including motor and respiratory rehabilitation, rheumatological follow-up, and referral for surgical evaluation of the fixed kyphotic deformity. This case highlights an advanced presentation of AS presenting primarily with spinal deformity rather than active pain. It emphasizes the importance of early recognition and regular assessment of spinal mobility in order to prevent irreversible structural damage and long-term functional impairment.