Sacroiliac joint pain: symptoms, causes and treatment

A private hospital spinal-services page describes the joints as a source of low back, buttock and leg pain, with pins and needles and numbness sometimes referred down the leg. It says function can be limited and sleep restricted, particularly when trying to turn over in bed.

Pain from the joint does not follow one tidy path. The same page says that, unlike sciatica caused by back nerves, symptoms do not follow a specific distribution, and can resemble pain from the back joints or hip, so diagnosis can be difficult.

For comparison, the NHS says sciatica happens when the sciatic nerve is irritated or compressed, with symptoms usually affecting the bottom and the back of one leg, so a careful history and examination are used to separate the two.

You have two sacroiliac joints, one on each side. Each joins the sacrum, the triangular bone at the base of the spine, to the iliac bone of the pelvis. Milton Keynes University Hospital describes them as large joints in the lower back.

They can become a source of pain. The hospital leaflet says inflammation or arthritic changes in the joints can cause pain in the back, or pain referred to the buttocks, sides or lower limbs.

Each joint has its own nerve supply, called the lateral branch nerves, which carry information about the joint, including pain from inflammation. This detail matters later because treatments such as nerve blocks and denervation target those nerves.

A private hospital spinal-services page lists several routes. Trauma, for example through normal childbirth or a traction or compression injury such as a road accident or fall, can set it off. Degenerative change, which may be age-related or linked to more load passing through the joint, for example after lumbar spinal fusion, is another.

A third group is inflammatory conditions of the spinal joints, called spondyloarthropathies, which include psoriatic arthritis and ankylosing spondylitis. Less commonly, Crohn's disease and ulcerative colitis can be linked to this type of arthritis.

Pregnancy is a further context. The NHS describes pelvic girdle pain in pregnancy as stiffness of the pelvic joints, or joints moving unevenly, at the back or front of the pelvis. Pain can be across one or both sides of the lower back, and worse when walking, climbing stairs or turning over in bed.

Ankylosing spondylitis is a long-term condition in which the spine and other areas become inflamed. The NHS says it is a type of axial spondyloarthritis and tends to develop first in teenagers and young adults. A closely related form, non-radiographic axial spondyloarthritis, shows changes on MRI but not on X-ray.

Symptoms usually involve back pain and stiffness, pain and swelling in other parts of the body, and extreme tiredness. They tend to develop gradually, usually over months or years, and may come and go.

The NHS says to see your GP if you have persistent symptoms, and that a GP who suspects it should refer you to a rheumatologist for tests. There is no cure, but exercise, physiotherapy and medicines such as anti-TNF treatment can relieve symptoms and help delay progression.

After a careful history, there are specific examination tests for the sacroiliac joint. A private hospital spinal-services page says clues in the history often raise suspicion, but the page acknowledges diagnosis can be difficult.

Blood tests can help look for an underlying inflammatory condition. Raised inflammatory markers or a positive test for the gene HLA-B27 can raise suspicion, but the page cautions these findings also occur in people without symptoms, so they are weighed alongside other findings.

Imaging has limits. X-rays of the sacroiliac joints and spine often show nothing in early problems, which can be falsely reassuring. MRI with specific sequences can pick up inflammatory or degenerative change but does not always show changes. The page adds that anti-inflammatory medicines may need to be stopped two weeks before an MRI, so follow the imaging team's instructions.

A diagnostic injection can confirm the source: local anaesthetic is placed around the nerves supplying the joint under X-ray guidance, and a change in symptoms while it works suggests the joint is responsible.

Early pain relief is emphasised. A private hospital spinal-services page says most pain medicines reduce symptoms without removing them entirely, and that evidence suggests people who have some relief move better, sleep better and recover more quickly. It states that anti-inflammatories are recommended for sacroiliac pain, and that a GP can prescribe other pain relief if they are unsuitable.

Manual therapy, particularly manipulation, has been shown to help people recover from sacroiliac joint pain, according to the same page. Learning how to exercise and manage flare-ups makes episodes easier to handle, and being physically fit makes recurrence less likely.

For back and joint problems in general, the NHS says some areas allow self-referral to community musculoskeletal services for physiotherapy without a GP referral, though waiting times can be long.

If pain persists despite medicines and manual therapy, orthopaedic and pain options exist. A sacroiliac block uses local anaesthetic to test whether the joint is the pain source. If symptoms change while it works, the person may be considered for radiofrequency denervation or fusion.

Radiofrequency denervation uses heat from a needle tip to interrupt the nerves carrying pain from the joint. The Milton Keynes leaflet explains that a diagnostic block is done first, then the heat treatment later, with a radiofrequency signal passed down the needle for 90 seconds. A private hospital spinal-services page notes nerves can grow back, so symptoms can return.

Risks listed by the leaflet include soreness or bruising, a temporary increase in pain for days or weeks, no pain relief, infection, bleeding, allergic reaction, temporary numbness or weakness in a leg, and rarely nerve injury. Steroid injected afterwards can disturb blood sugar control in people with diabetes for at least a week.

A private hospital spinal-services page describes minimally invasive fusion of the joint as approved by NICE for selected people who have had a diagnostic reduction in symptoms after a block. It is a considered decision with a spinal surgeon, after risks are discussed.

The NHS describes pelvic girdle pain (PGP) in pregnancy as a collection of uncomfortable symptoms caused by stiffness of the pelvic joints or the joints moving unevenly at the back or front of the pelvis. Pain may be felt over the pubic bone, across one or both sides of the lower back, between the vagina and anus, or spreading to the thighs, and can be worse when walking, going up or down stairs, standing on one leg or turning over in bed.

The NHS says PGP is not harmful to your baby, that most women with PGP can have a vaginal birth, and that you should call your midwife or GP if it is hard to move around, hurts to get out of a car or turn over in bed, or is painful on stairs. You may be referred to a specialist physiotherapy service and offered exercises or a pelvic support belt; the pain tends not to get completely better until the baby is born.

Back and pelvic pain are usually not serious, but the NHS says to call 999 or go to A&E if you have back pain with pain, tingling, weakness or numbness in both legs, a loss of feeling around the genitals or anus, changes in bladder or bowel control, chest pain, or if it started after a serious accident.

Ask for an urgent GP appointment or call NHS 111 if the pain is severe and starts suddenly or is getting worse quickly, or if you feel hot, cold, shivery or generally unwell. See a GP if pain has not improved after a few weeks of home treatment, is stopping you doing daily activities or is worse at night.

On the NHS, a GP can assess back and buttock pain and the NHS says in many areas you can refer yourself to community musculoskeletal (MSK) services for physiotherapy without a GP referral. Diagnostic blocks, radiofrequency denervation and fusion are provided through NHS pain and spinal services for selected patients. Private physiotherapy, pain clinics and spinal surgeons offer the same assessments and procedures with different waiting times; the hospital leaflets used for this page describe the steps in the same order.