Pain in Paget's disease

The Michael Davie Student Research Bursary was awarded to Kathryn Berg from the University of Edinburgh. [2019-2023]

Deciphering the mechanisms of pain in Paget’s

Kathryn Berg is a Research Assistant at the Institute of Genetics and Molecular Medicine, within the University of Edinburgh. With a Paget’s Association Student Bursary Funding her MSc she studied Pain in Paget’s (PiP). The Paget’s Association, in conjunction with the Michael Davie Research Foundation, awarded Kathryn a Student Research Bursary, which is enabling her to use her involvement with the Pain in Paget’s research study to work towards a master’s degree (MSc). Kathryn provides an insight into the study below.

The PiP project aims to achieve a greater understanding of the causes of pain in Paget’s disease. The research team are looking at the bacterial makeup of the mouth and gut, the markers of disease activity in the blood, and the genetics of volunteers recruited from hospitals across the UK. We are looking for 250 volunteers from across the country to help them with this important project. Patients who volunteer to get involved in the study are required to answer a questionnaire, undergo sensory testing, and provide blood and saliva samples. This takes about an hour and a half. Kathryn demonstrated the simple sensory tests and explained why they might help us to understand the pain associated with Paget’s disease.

Pain is one of the most common symptoms in patients with Paget’s Disease of Bone, affecting up to more than two-thirds of people diagnosed with the disorder. Although many patients experience a reduction in pain with bisphosphonate treatment (drugs such as Zoledronate and Risedronate are often used to treat Paget’s disease), it is becoming increasingly clear that pain can persist beyond treatment. The Paget’s Randomised trial of Intensive versus Symptomatic Management (PRISM) study, which was conducted by the Chair of the Paget’s Association, Professor Stuart Ralston, indicated that there was no significant difference in the pain experienced by patients who received symptomatic treatment with bisphosphonates, when compared to patients who received intensive treatment, indicating that managing bone turnover does not necessarily improve pain in all cases.

There are several likely causes of pain in patients with Paget’s disease. Pain could be from symptoms directly related to Paget’s disease, such as increased bone turnover, bone deformity, fractures, and nerve compression. Pain could also be unrelated to Paget’s disease, caused by a number of other conditions such as osteoarthritis, fibromyalgia, and neuropathic pain.

Aside from bisphosphonates, there are many different treatments available for patients who experience pain in Paget’s disease. In many cases, pain can be managed with analgesics such as ibuprofen and paracetamol, although opioids may be more appropriate in some cases. When nerve compression is a problem, specific drugs which aim to block this type of pain can be used. Immobilisation of joints can reduce pain in patients with more severe Paget’s, though this is rare. Non-drug treatments for pain include physiotherapy, occupational therapy, mindfulness, and peer support. The Paget’s Association runs support groups and events throughout the year.

The aim of the Pain in Paget’s (PiP) study is to reach a greater understanding of the prevalence and causes of pain in patients with Paget’s disease. The study team will look at the genetics of patients with the disease by carrying out a blood test. They will also look at the microbiome of Paget’s patients, using stool and saliva samples to examine whether there are any differences in the microorganisms living inside of patients. The microbiome is made up of around one trillion of these microorganisms which mostly live on our skin and in our gut. The microbiome is important for our health and is influenced by our diets. It is thought that the microbiome can influence bone metabolism and this could be a trigger for Paget’s disease and the pain associated with it. Using a process called Quantitative Sensory Testing (QST), the study team compared the skin above affected bone, with the skin above unaffected bone, to assess differences in sensation detection and pain thresholds. So far, the team have noticed a difference in the way that sensation is processed in the skin above Pagetic bone. From the data collected so far, it seems as though the skin overlying Pagetic bone is generally less sensitive to touch than the skin overlaying normal bone, although we must certain until all of the participants have been recruited!

Recruitment for the study has now ended and the results will be published in due course but at the time of writing, of the participants who were recruited to the study so far, 65% reported that they have musculoskeletal pain. Clinicians have determined that the cause of pain in around half of these participants is actually osteoarthritis. On the 12th March 2020, the PiP study hit the incredible milestone of 50 participants who have come into hospitals across the country to help them with this important research! The PiP team are incredibly grateful to the participants who came to clinic. 

Kathryn Berg