Sarcoidosis and musculoskeletal disease
Sarcoidosis is a disease characterised by the growth of tiny collections of inflammatory cells (granulomas) in any body tissue — most commonly the lungs and lymph nodes. But it can also affect the eyes, skin, heart and other organs.
The cause of sarcoidosis is unknown, but it is most likely an autoimmune response to an external antigen such infectious agents, chemicals, and dust. There is a genetic predisposition to sarcoidosis.
Muscular involvement is a common feature of sarcoidosis but is usually asymptomatic. The four clinical subtypes of muscular sarcoidosis have been characterised as:
- Acute myositis
- Chronic myopathic
- Palpable nodular
In general, acute myositis is accompanied by fevers, muscle pain and elevated muscle enzymes. Chronic myopathic types tend to be associated with muscle atrophy and weakness. The palpable nodular type presents as non-tender masses within muscles.
This case report highlights an unusual presentation of calcific tendinitis secondary to sarcoidosis, in an even more unusual place, the piriformis tendon.
- 42-year-old man presented with a 7-day history of left hip pain.
- Started after he went for a 30-minute evening run.
- He developed non-specific pain around his left hip later that evening and over the following days.
- Pain got progressively worse to the point he was bed bound and unable to walk.
- Seen at LBSM on day 7, he was unable to fully weight bear and was mobilising with a crutch.
- He denied systemic symptoms such as fatigue, myalgia, anorexia and weight loss.
- He had a similar episode to this 8 years ago at which time he was diagnosed with a gluteal abscess which was self-limiting. Blood tests at the time revealed normal white cell count and inflammatory markers.
Past Medical history;
- Sarcoidosis affecting his lungs, skin and eyes. No previous joint involvement. He had not had flare for 10 years and was not taking any medication.
- Serum corrected calcium levels were consistently elevated over many years at 2.55 mmol/L.
- He is fit and active, running three or four times a week.
He works as an accountant and had been working for home through the COVID-19 pandemic.
- On initial examination he was unable to fully weight bear on his left leg and was walking with a limp.
- Unable to walk up or down stairs and could not maintain a single leg balance.
- Reduced range in all movements of the left hip
- Pain could not be directly reproduced through palpation.
- Urgent left hip and pelvis MRI was ordered and the patient was advised to offload until the results were back.
Left Image – MRI (STIR 1 sequencing) imaging demonstrating a coronal view of calcific changes within the left piriformis muscle and tendon.
Right image – MRI imaging with axial view of calcific changes within the left piriformis muscle and tendon.
- Patient asked to partially weight bear through left hip for one week, with the use 2 crutches.
- Transitioned onto a gentle isometric loading programme with body weight and bands by end of first week.
- Returned to full weight bearing gradually over a period of 2 weeks.
- Restricted step count to 3000/day until completely pain free and then progressively increased to 10000/day (over period of 2 weeks).
- Heavier loading programme for deep gluteal muscles and piriformis specific stretches started at 4 weeks.
- Ultrasound guided corticosteroid and local anaesthetic injection into calcific portion of piriformis tendon insertion in first week which produced immediate positive response to pain.
- Patient then prescribed 1 month course of anti-inflammatories and PPI cover.
Patient Self-monitoring tools
Patient completed LBSM pain and symptom diary throughout treatment
Key Summary – Calcific tendinitis and Sarcoidosis
- Calcific tendonitis refers to a build-up of calcium in the tendon complex.
- This can cause a build up of pressure in the tendon, as well causing a chemical irritation.
- Typically calcific tendinitis is acute or acute on chronic and extremely painful when “flares”.
- In addition to the chemical irritation and pressure, the calcific deposit reduces the space between adjacent structures and inflammation (demonstrated by the high signal in the muscle).
- It typically occurs in in the rotator cuff, patella tendon and gluteus medius tendon.
- Conditions that elevation serum calcium, will naturally predispose to calcium deposits in the body.
- No laboratory tests are diagnostic of sarcoidosis.
- Elevated serum calcium is a recognised abnormality associated with sarcoidosis and is seen in 10% of all patients with sarcoidosis.
- Hypercalcaemia in sarcoidosis is thought to be due to the overproduction of vitamin D by macrophages in the sarcoid granuloma due to disruption in feedback regulation.
- Malignancy should always be considered as a differential diagnosis in patients with elevated hypercalcaemia.