This 45-year-old gentleman came to see me for some analgesia. His back had been playing up for years. A succession of physiotherapy appointments, an acupuncture session and some private osteopathy hadn’t helped.
But more apparent to me was the way he held his neck. It was flexed and seemed quite rigid. I asked him about it. He admitted he couldn’t even drink out of a can anymore without bending his knees and moving his whole trunk back.
He hadn’t been able to bend his neck back to look up at the sky either. When I asked him to bend over and touch his toes, there was barely any widening of his inter-vertebral distance (Schober’s test). An alarm bell rang in my head.
Something wasn’t right about this man generally. His whole axial skeleton seemed stiff. It was as if he had been in a freezer.
I wondered about an inflammatory arthropathy and ankylosing spondylitis was top of my list.
• Ankylosing spondylitis
• Cervical spondylosis
• Rheumatoid arthritis.
Anklyosing spondylitis is a rare (0.1-0.2% of the population), chronic, seronegative arthritis characterised by axial skeleton enthesopathy.
Some 90-95% of sufferers carry the human leucocyte antigen B27, compared with just 7% of the normal population. Only 1% of HLA-B27 carriers progress onto ankylosing spondylitis, a process thought to be triggered by an unknown environmental factor. This was a diagnosis I had to rule out.
Cervical spondylosis is a degenerative condition of the cervical vertebrae typically associated with age.
There can be associated hypertrophy of the ligamentum flavum and ossification of the posterior longitudinal ligament. I would expect blood results to be normal with this.
Rheumatoid arthritis was a possibility, but usually affects the proximal joints symmetrically. Around 70% of rheumatoid patients are rheumatoid factor positive, and 30% anti-nuclear antibody positive. Some 2% of the healthy young population are rheumatoid factor positive too, a proportion that increases to as high as 20% after 65 years of age.
Getting on the right track
I dug out his old notes and interestingly he had been complaining of back ache and a sore neck as early as 1994. The first step was some blood tests and an X-ray. His CRP was slightly raised at 15 but his ESR was normal at 11 and rheumatoid factor was negative.
An X-ray of his lower back showed loss of lumbar lordosis and sclerotic changes at the sacroiliac joints. The HLA-B27 I ordered was positive.
Two months later, a consultant rheumatologist confirmed the diagnosis of ankylosing spondylitis clinically using the New York criteria.1
The patient is now undergoing tuberculosis screening prior to receiving a monoclonal antibody therapy and is having aquatherapy.
Average time to diagnosis for ankylosing spondylitis is said to be 14 years, so we were a little over at 16 years.
Dr Oliver Starr is a sessional GP in Hertfordshire
Back ache and rigid neck Back ache