Thursday, 9 September 2010

MRCP revision battle 6.1: ankylosing spondylitis

Today's revision threw up a mixed bag of topics... a splash of rheumatology with a dash of respiratory and a hint of ophthalmology.


Battle 6.1: ankylosing spondylitis
Battle 6.2: acute iritis
Battle 6.3: Reiters syndrome
Battle 6.4: pleural effusion
Battle 6.5 yellow nail syndrome

Lets get started!

6.1: Ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease of the spine and sacroiliac joints.

It affects males more than females, intially around 6:1 but altering to around 2:1 by the age of 30.

 95% of patients are + for HLA B27

Patients often present with low back pain which is worse at night and improves on moving.

Clinically, the things to observe on regarding a patient with AS are:
  • a loss of lumbar lordosis
  • a fixed kyphosis which is compensated by extension of the cervical spine leading to the classical 
  • 'question mark' posture
  • if the patient turns their head to the side, the whole body may turn
  • there may be decreased chest expansion forcing increased diaphragmatic excursion and hence a
  • prominent abdomen
A possible test to undertake is Schobers test - find L5 (roughly level with the sacral dimples) then mark a level 5cm below and 10cm above.  Get the patient to bend over; this 15cm distance should increase to at least 20cm, if it doesn't is suggests AS.

    Associations of AS include:
    • iritis
    • aortic regurgitation
    • fibrosis (rare)
    • cardiac conduction abnormalities (around 10%, mostly long PR)
    • secondary amyloidosis

    Management is keeping mobile, NSAIDs and in severe cases tumour necrosis factor alpha blockers such as infliximab.

    As an aside, if considering a TNF alpha blocker its a good idea to check TB status as it is likely to reactivate latent TB.

    Onwards.... 6.2!