Dr Lucy Birtwistle1, Dr Neha Chandrasekar1, Dr Rivindu Wijayaratne1, Dr Akshay Athavale1,2,3
1Department of Renal Medicine, Gosford Hospital, Gosford, Australia, 2School of Medicine and Public Health, University of Newcastle, Newcastle, Australia , 3Faculty of Medicine and Health, Macquarie University, Macquarie, Australia
Biography:
Lucy Birtwistle is a Basic Physician Trainee with a budding interest in nephrology. She recently completed her term in renal medicine at Gosford Hospital and has trained as a junior doctor at Royal North Shore Hospital and Port Macquarie Base Hospital. She has an interest in clinical and translational research having studied medicine and advanced science at the University of Sydney. She has conducted research into therapeutic role of mesenchymal stem cell-derived extracellular vesicles in acute kidney injury, operative outcomes of adrenal tumours, CAR T-cell therapy, and presented a case on neonatal autoimmune haemolytic disease secondary to maternal Evans syndrome.
Background:
Pruritus associated with chronic kidney disease (CKD-aP) is a prevalent, burdensome, and underdiagnosed condition linked with depression and a reduced quality of life. The pathophysiology of CKD-aP is poorly understood and multifactorial involving immune dysregulation, peripheral neuropathy and endogenous opioid imbalance, with subsequent inflammation and xerosis. Current treatments including emollients, antihistamines, gabapentinoids, and corticosteroids have limited efficacy. Difelikefalin acetate is the first drug approved in Australia to treat moderate to severe CKD-aP. It is a selective kappa-opioid receptor agonist resulting in reduced pruritus and inflammation in CKD. Usual dosing is 0.5 mcg/kg three times per week after haemodialysis.
Case Report:
We report a case of refractory CKD-aP treated with difelakefalin in a 57-year-old male receiving twice weekly in-centre haemodialysis. The patient was receiving dialysis for nine months after sustaining a severe anuric acute kidney injury. Pruritus was a prominent feature since dialysis initiation and severely impacted his quality of life. Severe excoriations secondary to pruritus, diffuse rash and hyperalgesia, resulted in severe agitation, and sleep and mood disturbance. Standard treatments including emollients, sedating and non-sedating antihistamines, and gabapentinoids were ineffective. Dermatologic recommendations including topical corticosteroids resulted in temporary benefit, though effects were not sustained. After months of unsuccessful treatment, difelikefalin acetate 25 mcg twice weekly on haemodialysis was initiated. This resulted in a rapid and sustained improvement in itch intensity, tolerability and quality of life without incidence of adverse events.
Conclusion:
This unique case highlights the benefits of difelikefalin in alleviating severe CKD-aP even using a reduced dose frequency of twice weekly. While the product information for difelakefalin indicates three times a week dosing, less frequent dosing may still yield positive outcomes for patients.