<s>[INST] context: The information in question are 40yr male Morning stiffness in spine Limited chest expansion *****all fit into clinical criteria for diagnosis of Ankylosing spondylitis x ray of ankylosing spondylitis -BAMBOO SPINE AS is a chronic, progressive immune-mediated inflammatory disorder that results in ankylosis of the veebral column and sacroiliac joints . * The spine and sacroiliac joints are the common affected sites -- Chronic spinal inflammation (spondylitis) can lead to fusion of veebrae (ankylosis) . Characteristic Pathologic Features : * Chronic inflammation in: - Axial structures (sacroiliac joint, spine, anterior chest wall, shoulder and hip) - Possibly large peripheral joints, mainly at the lower limbs (oligoahritis) - Entheses (enthesitis) * Bone formation paicularly in the axial joints Axial manifestations: * Chronic low back pain * With or without buttock pain * Inflammatory characteristics: - Occurs at night (second pa) - Sleep disturbance - Morning stiffness * Limited lumbar motion * Onset before age of 40 years Refer maheswari 9th ed [/INST] question: 40yr old male patient having pain with daily morning stiffness of spine for 30 minutes and reduced chest movements. Most probable diagnosis is | options: A: Ankylosing spondylitis B: Rheumatoid ahritis C: Gouty ahritis D: Osteoahritis | answer: A </s>