Hyperuricaemia & Gout by Z Ngwira-unza

Description

This lecture by Z Ngwira provides a comprehensive overview of hyperuricaemia and gout, detailing the biochemistry, pathophysiology, clinical presentation, and management of these conditions. It begins by explaining that uric acid is the end product of purine catabolism from adenine and guanine, existing in plasma as sodium urate. Hyperuricaemia, an elevated serum urate concentration, arises from increased production or decreased excretion, with most primary cases due to reduced renal clearance. The formation of urate occurs through de novo synthesis, metabolism of endogenous purines, and breakdown of dietary nucleic acids, while excretion is primarily renal, involving complex filtration, reabsorption, and secretion processes, with a minor gut component via uricolysis. The presentation highlights genetic disorders like Lesch-Nyhan syndrome, caused by an enzyme deficiency leading to excessive uric acid production and neurological issues. Gout is characterized by hyperuricaemia and acute arthritis triggered by sodium urate crystal deposition in joints, causing intense inflammation, and can become chronic with tophaceous deposits. Exacerbating factors include alcohol, which increases urate production and impairs excretion, and conditions like diabetic ketoacidosis that elevate organic acids. Treatment strategies for acute gout involve anti-inflammatory drugs like indomethacin, while long-term management focuses on lowering serum urate with uricosuric agents (e.g., probenecid), xanthine oxidase inhibitors (e.g., allopurinol), and dietary modifications. The lecture also covers renal complications, such as urate nephropathy and stones, and the risk of acute renal failure during tumour lysis in malignancies, where urate oxidase may be used prophylactically. Additionally, it notes the monitoring of serum urate in pregnancy-associated hypertension. This resource is essential for biomedical science and medical students in Zambia, offering foundational knowledge for understanding, diagnosing, and managing disorders of purine metabolism and their clinical consequences. Use this guide to enhance your proficiency in metabolic pathology and therapeutic approaches.