Urinary tract infections (UTIs) are painful and usually short-lived – but in many people low levels of infection can be found long after it's thought to have cleared.
The latest research led by Flinders University has now identified a link between UTI and bladder pain – caused by the immune system's fight against the infection.
The research suggests this could be a leading cause of chronic bladder dysfunction.
The new insights investigate how the immune system's defence against bladder infection causes nerves to magnify the sensations felt by patients, giving hope for new treatments to combat debilitating symptoms including pain, discomfort and a constant urge to urinate.
Flinders University researchers at SAHMRI, in collaboration with Griffith University on the Gold Coast, have analysed how the immune system responds to urinary tract infections and the direct link this response has to increase bladder pain.
Clinical Pharmacology Research Fellow and Head of Bladder Research, Dr Luke Grundy, says understanding how nerves in the bladder transmit different sensations to the brain could potentially help limit bladder dysfunction in overactive bladder patients.
"We believe that chronic pain and bladder dysfunction are a failure of these nerves to reset after inflammation, so by understanding how these nerves function with a UTI and what causes them to become more sensitive over time, we can develop effective treatments," Dr Grundy says.
"This is important, as many people diagnosed with an overactive bladder, a disorder that is currently considered to have no specific cause, have a history of urinary tract infections, and have been shown to have persistent low levels of UTI.
"This may lead to enhanced patient diagnosis and alternative treatment options for those suffering with an overactive bladder."
With the number of antibiotic-resistant UTIs growing globally each year, many can no longer be treated with common antibiotics despite the fact one in every two women will develop a UTI in their lifetime.
Dr Grundy says this study provides new information into how UTI causes hypersensitivity of the nerves that carry sensation from the bladder to the brain, resulting in the symptoms of urinary frequency, urgency, and pelvic or suprapubic pain.
"Our study provides a new understanding of why some overactive bladder patients do not respond to traditional medications and continue to suffer in silence, and opens the door for the development of more specific and effective treatments in the future."
The research paper, 'Innate immune response to bacterial urinary tract infection sensitises high-threshold bladder afferents and recruits silent nociceptors' (2020) by SM Brierley, KGK Goh, MJ Sullivan, KH Moore, GC Ulett and L Grundy has been published in the journal Pain. DOI: 10.1097/j.pain.0000000000001692
TNext month, Flinders University will co-host and present at the 4th Meeting of the Federation of NeuroGastroenterology and Motility in Adelaide from 24 to 28 March 2020.
Leading gut researchers, including Flinders Professor Nick Spencer and Professor Stuart Brierley, will chair sessions during the week-long conference which will also delve into the latest gut-brain research and developments.
